5696 lines
309 KiB
Plaintext
5696 lines
309 KiB
Plaintext
处理第 1/832 条数据...
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[
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{
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"question": "Temperature indicators are sometimes produced from a coiled metal strip that uncoils a specific amount when the temperature increases. How does this work?",
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"answer": "Bimetallic materials are produced by bonding two materials having different coefficients of thermal expansion to one another, forming a laminar composite. When the temperature changes, one of the materials will expand or contract more than the other material. This difference in expansion or contraction causes the bimetallic material to change shape; if the original shape is that of a coil, then the device will coil or uncoil, depending on the direction of the temperature change."
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},
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{
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"question": "From what kind of material would the temperature indicator be made?",
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"answer": "The temperature indicator is made from bimetallic materials, which consist of two materials with different coefficients of thermal expansion bonded together."
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},
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{
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"question": "What are the important properties that the material in the temperature indicator must possess?",
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"answer": "In order for the material to perform well, the two materials must have very different coefficients of thermal expansion and should have high enough modulus of elasticity so that no permanent deformation of the material occurs."
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}
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]
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[
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{
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"question": "What properties should the head of a carpenter's hammer possess?",
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"answer": "The striking face and claws of the hammer should be hard-the metal should not dent or deform when driving or removing nails. Yet these portions must also possess some impact resistance, particularly so that chips do not flake off the striking face and cause injuries."
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},
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{
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"question": "How would you manufacture a hammer head?",
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"answer": "The head for a carpenter's hammer is produced by forging, a metalworking process; a simple steel shape is heated and formed in several steps while hot into the required shape. The head is then heat treated to produce the required mechanical and physical properties."
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}
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]
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```json
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[
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{
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"question": "Using the densities and atomic weights, calculate the number of atoms per cubic centimeter in lead.",
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"answer": "3.3 × 10^22 atoms/cm^3"
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},
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{
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"question": "Using the densities and atomic weights, calculate the number of atoms per cubic centimeter in lithium.",
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"answer": "4.63 × 10^22 atoms/cm^3"
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}
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]
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```
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```json
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[
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{
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"question": "In order to plate a steel part having a surface area of 200 in.^2 with a 0.002 in. thick layer of nickel, how many atoms of nickel are required?",
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"answer": "5.98 x 10^23 atoms"
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},
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{
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"question": "In order to plate a steel part having a surface area of 200 in.^2 with a 0.002 in. thick layer of nickel, how many moles of nickel are required?",
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"answer": "0.994 mol ni required"
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}
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]
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```
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[
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{
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"question": "Calculate the atomic radius in cm for a BCC metal with a0=0.3294 nm and one atom per lattice point.",
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"answer": "1.426 x 10^-8 cm"
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},
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{
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"question": "Calculate the atomic radius in cm for an FCC metal with a0=4.0862 A and one atom per lattice point.",
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"answer": "1.4447 x 10^-8 cm"
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}
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]
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[
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{
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"question": "Determine the crystal structure for a metal with a0=4.9489 Å, r=1.75 Å and one atom per lattice point.",
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"answer": "fcc."
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},
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{
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"question": "Determine the crystal structure for a metal with a0=0.42906 nm, r=0.1858 nm and one atom per lattice point.",
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"answer": "bcc."
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}
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]
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[
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{
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"question": "The density of potassium, which has the BCC structure and one atom per lattice point, is 0.855 g/cm3. The atomic weight of potassium is 39.09 g/mol. Calculate the lattice parameter.",
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"answer": "5.3355 x 10^-8 cm"
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},
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{
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"question": "The density of potassium, which has the BCC structure and one atom per lattice point, is 0.855 g/cm3. The atomic weight of potassium is 39.09 g/mol. Calculate the atomic radius of potassium.",
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"answer": "2.3103 x 10^-8 cm"
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}
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]
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```json
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[
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{
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"question": "The density of thorium, which has the FCC structure and one atom per lattice point, is 11.72 g/cm³. The atomic weight of thorium is 232 g/mol. Calculate the lattice parameter.",
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"answer": "5.0856 x 10⁻⁸ cm"
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},
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{
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"question": "The density of thorium, which has the FCC structure and one atom per lattice point, is 11.72 g/cm³. The atomic weight of thorium is 232 g/mol. Calculate the atomic radius of thorium.",
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"answer": "1.7980 x 10⁻⁸ cm"
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}
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]
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```
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[
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{
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"question": "Bismuth has a hexagonal structure, with a0=0.4546 nm and c0=1.186 nm. The density is 9.808 g/cm3 and the atomic weight is 208.98 g/mol. Determine the volume of the unit cell.",
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"answer": "0.21226 nm3 or 2.1226 x 10^-22 cm3"
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},
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{
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"question": "Bismuth has a hexagonal structure, with a0=0.4546 nm and c0=1.186 nm. The density is 9.808 g/cm3 and the atomic weight is 208.98 g/mol. Determine the number of atoms in each unit cell.",
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"answer": "6 atoms/cell"
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}
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]
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```json
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[
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{
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"question": "Gallium has an orthorhombic structure, with a0=0.45258 nm, b0=0.45186 nm, and c0=0.76570 nm. The atomic radius is 0.1218 nm. The density is 5.904 g/cm3 and the atomic weight is 69.72 g/mol. Determine the number of atoms in each unit cell.",
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"answer": "8 atoms/cell."
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},
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{
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"question": "Gallium has an orthorhombic structure, with a0=0.45258 nm, b0=0.45186 nm, and c0=0.76570 nm. The atomic radius is 0.1218 nm. The density is 5.904 g/cm3 and the atomic weight is 69.72 g/mol. Determine the packing factor in the unit cell.",
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"answer": "0.387."
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}
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]
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```
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[
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{
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"question": "Beryllium has a hexagonal crystal structure, with a0=0.22858 nm and c0=0.35842 nm. The atomic radius is 0.1143 nm, the density is 1.848 g/cm3, and the atomic weight is 9.01 g/mol. Determine the number of atoms in each unit cell.",
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"answer": "2 atoms/cell."
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},
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{
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"question": "Beryllium has a hexagonal crystal structure, with a0=0.22858 nm and c0=0.35842 nm. The atomic radius is 0.1143 nm, the density is 1.848 g/cm3, and the atomic weight is 9.01 g/mol. Determine the packing factor in the unit cell.",
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"answer": "0.77"
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}
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]
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[
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{
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"question": "A typical paper clip weighs 0.59 g and consists of BCC iron. Calculate the number of unit cells in the paper clip.",
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"answer": "3.185 × 10^21 cells"
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},
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{
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"question": "A typical paper clip weighs 0.59 g and consists of BCC iron. Calculate the number of iron atoms in the paper clip.",
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"answer": "6.37 × 10^21 atoms"
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}
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]
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```json
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[
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{
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"question": "Determine the planar density for BCC lithium in the (100) plane.",
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"answer": "planar density = 0.0812 x 10^16 points/cm^2"
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},
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{
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"question": "Determine the packing fraction for BCC lithium in the (100) plane.",
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"answer": "packing fraction = 0.589"
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},
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{
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"question": "Determine the planar density for BCC lithium in the (110) plane.",
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"answer": "planar density = 0.1149 x 10^16 points/cm^2"
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},
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{
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"question": "Determine the packing fraction for BCC lithium in the (110) plane.",
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"answer": "packing fraction = 0.833"
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},
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{
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"question": "Determine the planar density for BCC lithium in the (111) plane.",
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"answer": "planar density = 0.0469 x 10^16 points/cm^2"
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},
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{
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"question": "Determine the packing fraction for BCC lithium in the (111) plane.",
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"answer": "packing fraction = 1/2 / 0.866 a0^2 sqrt(3) a0 / 4"
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},
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{
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"question": "Which, if any, of these planes is close packed in BCC lithium?",
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"answer": "there is no close-packed plane in bcc structures."
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}
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]
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```
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```json
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[
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{
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"question": "Determine the minimum radius of an atom that will just fit into the tetrahedral interstitial site in FCC nickel.",
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"answer": "0.2797 \aa"
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},
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{
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"question": "Determine the minimum radius of an atom that will just fit into the octahedral interstitial site in BCC lithium.",
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"answer": "0.629 \aa"
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}
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]
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```
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API调用错误: Invalid \escape: line 4 column 27 (char 170)
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处理第 43/832 条数据...
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```json
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[
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{
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"question": "Would you expect BeO to have the sodium chloride, zinc blende, or fluorite structure?",
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"answer": "BeO has the zinc blende structure."
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},
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{
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"question": "Based on the zinc blende structure of BeO, determine the lattice parameter.",
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"answer": "The lattice parameter is 3.8567 Å."
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},
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{
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"question": "Based on the zinc blende structure of BeO, determine the density.",
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"answer": "The density is 2.897 g/cm³."
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},
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{
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"question": "Based on the zinc blende structure of BeO, determine the packing factor.",
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"answer": "The packing factor is 0.684."
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}
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]
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```
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[
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{
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"question": "Would you expect CsBr to have the sodium chloride, zinc blende, fluorite, or cesium chloride structure?",
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"answer": "CsBr is expected to have the cesium chloride structure."
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},
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{
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"question": "Based on the cesium chloride structure, determine the lattice parameter for CsBr.",
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"answer": "The lattice parameter a0 = 4.1916 Å."
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},
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{
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"question": "Based on the cesium chloride structure, determine the density for CsBr.",
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"answer": "The density ρ = 4.8 g/cm3."
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},
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{
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"question": "Based on the cesium chloride structure, determine the packing factor for CsBr.",
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"answer": "The packing factor pf = 0.693."
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}
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]
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```json
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[
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{
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"question": "Sketch the ion arrangement on the (110) plane of ZnS (with the zinc blende structure).",
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"answer": ""
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},
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{
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"question": "Sketch the ion arrangement on the (110) plane of CaF2 (with the fluorite structure).",
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"answer": ""
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},
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{
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"question": "Compare the ion arrangement on the (110) plane of ZnS (with the zinc blende structure) to that on the (110) plane of CaF2 (with the fluorite structure).",
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"answer": ""
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},
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{
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"question": "Calculate the planar packing fraction (ppf) on the (110) plane for ZnS (with the zinc blende structure).",
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"answer": "0.492"
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},
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{
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"question": "Calculate the planar packing fraction (ppf) on the (110) plane for CaF2 (with the fluorite structure).",
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"answer": "0.699"
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},
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{
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"question": "Compare the planar packing fraction (ppf) on the (110) planes for ZnS (with the zinc blende structure) and CaF2 (with the fluorite structure).",
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"answer": ""
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}
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]
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```
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处理第 46/832 条数据...
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[
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{
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"question": "MgO, which has the sodium chloride structure, has a lattice parameter of 0.396 nm. Determine the planar density and the planar packing fraction for the (111) plane of MgO. What ions are present on this plane?",
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"answer": "(111) plane:\n- planar density (p.d.): 0.1473 x 10^16 points/cm^2\n- planar packing fraction (ppf): 0.202\n- ions present: mg^2+ and o^2-"
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},
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{
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"question": "MgO, which has the sodium chloride structure, has a lattice parameter of 0.396 nm. Determine the planar density and the planar packing fraction for the (222) plane of MgO. What ions are present on this plane?",
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"answer": "(222) plane:\n- planar density (p.d.): 0.1473 x 10^16 points/cm^2\n- planar packing fraction (ppf): 0.806\n- ions present: mg^2+ and o^2-"
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}
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]
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```json
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[
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{
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"question": "The density of a sample of HCP beryllium is 1.844 g/cm³ and the lattice parameters are a₀=0.22858 nm and c₀=0.35842 nm. Calculate the fraction of the lattice points that contain vacancies.",
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"answer": "0.0008"
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},
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{
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"question": "The density of a sample of HCP beryllium is 1.844 g/cm³ and the lattice parameters are a₀=0.22858 nm and c₀=0.35842 nm. Calculate the total number of vacancies in a cubic centimeter.",
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"answer": "0.986 × 10²⁰ vacancies/cm³"
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}
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]
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```
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处理第 51/832 条数据...
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[
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{
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"question": "BCC lithium has a lattice parameter of 3.5089 × 10^-8 cm and contains one vacancy per 200 unit cells. Calculate the number of vacancies per cubic centimeter.",
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"answer": "1.157 × 10^20 vacancies/cm³"
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},
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{
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"question": "BCC lithium has a lattice parameter of 3.5089 × 10^-8 cm and contains one vacancy per 200 unit cells. Calculate the density of Li.",
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"answer": "0.532 g/cm³"
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}
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]
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[
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{
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"question": "FCC lead has a lattice parameter of 0.4949 nm and contains one vacancy per 500 Pb atoms. Calculate the density.",
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"answer": "the density is 11.335 g/cm3."
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},
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{
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"question": "FCC lead has a lattice parameter of 0.4949 nm and contains one vacancy per 500 Pb atoms. Calculate the number of vacancies per gram of Pb.",
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"answer": "the number of vacancies per gram of pb is 5.82 × 10^18 vacancies/g."
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}
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]
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[
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{
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"question": "Suppose we introduce one carbon atom for every 100 iron atoms in an interstitial position in BCC iron, giving a lattice parameter of 0.2867 nm. For the Fe-C alloy, find the density.",
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"answer": "7.89 g/cm³"
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},
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{
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"question": "Suppose we introduce one carbon atom for every 100 iron atoms in an interstitial position in BCC iron, giving a lattice parameter of 0.2867 nm. For the Fe-C alloy, find the packing factor.",
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"answer": "0.681"
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}
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]
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```json
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[
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{
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"question": "The density of BCC iron is 7.882 g/cm³ and the lattice parameter is 0.2886 nm when hydrogen atoms are introduced at interstitial positions. Calculate the atomic fraction of hydrogen atoms.",
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"answer": "0.004"
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},
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{
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"question": "The density of BCC iron is 7.882 g/cm³ and the lattice parameter is 0.2886 nm when hydrogen atoms are introduced at interstitial positions. Calculate the number of unit cells required on average that contain hydrogen atoms.",
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"answer": "123.5"
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}
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]
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```
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[
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{
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"question": "Suppose one Schottky defect is present in every tenth unit cell of MgO. MgO has the sodium chloride crystal structure and a lattice parameter of 0.396 nm. Calculate the number of anion vacancies per cm3.",
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"answer": "the number of anion vacancies per cm3 is 1.61 × 10^21 vacancies/cm^3."
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},
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{
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"question": "Suppose one Schottky defect is present in every tenth unit cell of MgO. MgO has the sodium chloride crystal structure and a lattice parameter of 0.396 nm. Calculate the density of the ceramic.",
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"answer": "the density of the ceramic is 4.205 g/cm^3."
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}
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]
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```json
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||
[
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{
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"question": "ZnS has the zinc blende structure. If the density is 3.02 g/cm3 and the lattice parameter is 0.59583 nm, determine the number of Schottky defects per unit cell.",
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"answer": "0.0535 defects per unit cell."
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},
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{
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"question": "ZnS has the zinc blende structure. If the density is 3.02 g/cm3 and the lattice parameter is 0.59583 nm, determine the number of Schottky defects per cubic centimeter.",
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"answer": "2.517 × 10^20 defects per cm3."
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}
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]
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```
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[
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{
|
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"question": "Calculate the length of the Burgers vector in BCC niobium",
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"answer": "b = 2.853 \u00c5"
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},
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{
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"question": "Calculate the length of the Burgers vector in FCC silver",
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"answer": "b = 2.889 \u00c5"
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},
|
||
{
|
||
"question": "Calculate the length of the Burgers vector in diamond cubic silicon",
|
||
"answer": "b = 3.840 \u00c5"
|
||
}
|
||
]
|
||
处理第 61/832 条数据...
|
||
[
|
||
{
|
||
"question": "A single crystal of an FCC metal is oriented so that the direction is parallel to an applied stress of 5000 psi. Calculate the resolved shear stress acting on the (111) slip plane in the [T slip direction.",
|
||
"answer": "the resolved shear stress acting on the (111) slip plane in the [T slip direction is 0."
|
||
},
|
||
{
|
||
"question": "A single crystal of an FCC metal is oriented so that the direction is parallel to an applied stress of 5000 psi. Calculate the resolved shear stress acting on the (111) slip plane in the [T] slip direction.",
|
||
"answer": "the resolved shear stress acting on the (111) slip plane in the [T] slip direction is 2040 psi (active)."
|
||
},
|
||
{
|
||
"question": "A single crystal of an FCC metal is oriented so that the direction is parallel to an applied stress of 5000 psi. Which slip system(s) will become active first?",
|
||
"answer": "the slip systems that will become active first are λ011 and λ101."
|
||
}
|
||
]
|
||
处理第 62/832 条数据...
|
||
[
|
||
{
|
||
"question": "A single crystal of a BCC metal is oriented so that the direction is parallel to the applied stress. If the critical resolved shear stress required for slip is 12,000 psi, calculate the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction on the (110) slip plane.",
|
||
"answer": "the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction is: on the (110) slip plane: σ = ∞"
|
||
},
|
||
{
|
||
"question": "A single crystal of a BCC metal is oriented so that the direction is parallel to the applied stress. If the critical resolved shear stress required for slip is 12,000 psi, calculate the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction on the (011) slip plane.",
|
||
"answer": "the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction is: on the (011) slip plane: σ = 29,412 psi"
|
||
},
|
||
{
|
||
"question": "A single crystal of a BCC metal is oriented so that the direction is parallel to the applied stress. If the critical resolved shear stress required for slip is 12,000 psi, calculate the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction on the (101) slip plane.",
|
||
"answer": "the magnitude of the applied stress required to cause slip to begin in the [1,-1,1] direction is: on the (101) slip plane: σ = 29,412 psi"
|
||
}
|
||
]
|
||
处理第 63/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "The strength of titanium is found to be 65,000 psi when the grain size is 17 x 10^-6 m and 82,000 psi when the grain size is 0.8 x 10^-6 m. Determine the constants in the Hall-Petch equation.",
|
||
"answer": "the constants in the hall-petch equation are k = 19.4 psi/sqrt(d) and σ_o = 60,290 psi."
|
||
},
|
||
{
|
||
"question": "The strength of titanium is found to be 65,000 psi when the grain size is 17 x 10^-6 m and 82,000 psi when the grain size is 0.8 x 10^-6 m. Determine the strength of the titanium when the grain size is reduced to 0.2 x 10^-6 m.",
|
||
"answer": "the strength of the titanium when the grain size is reduced to 0.2 x 10^-6 m is 103,670 psi."
|
||
}
|
||
]
|
||
```
|
||
处理第 64/832 条数据...
|
||
[
|
||
{
|
||
"question": "For an ASTM grain size number of 8, calculate the number of grains per square inch at a magnification of 100.",
|
||
"answer": "128 grains/in.^2"
|
||
},
|
||
{
|
||
"question": "For an ASTM grain size number of 8, calculate the number of grains per square inch with no magnification.",
|
||
"answer": "1.28 × 10^6 grains/in.^2"
|
||
}
|
||
]
|
||
处理第 65/832 条数据...
|
||
It's a single issue.
|
||
处理第 66/832 条数据...
|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
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|
||
处理第 70/832 条数据...
|
||
[
|
||
{
|
||
"question": "The diffusion coefficient for Cr+3 in Cr2O3 is 6x10^-15 cm^2/s at 727C and is 1x10^-9 cm^2/s at 1400C. Calculate the activation energy q.",
|
||
"answer": "the activation energy q is 59,230 cal/mol."
|
||
},
|
||
{
|
||
"question": "The diffusion coefficient for Cr+3 in Cr2O3 is 6x10^-15 cm^2/s at 727C and is 1x10^-9 cm^2/s at 1400C. Calculate the constant d0.",
|
||
"answer": "the constant d0 is 0.055 cm^2/s."
|
||
}
|
||
]
|
||
处理第 71/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 0.2-mm thick wafer of silicon is treated so that a uniform concentration gradient of antimony is produced. One surface contains 1 Sb atom per 10^8 Si atoms and the other surface contains 500 Sb atoms per 10^8 Si atoms. The lattice parameter for Si is 5.407 A. Calculate the concentration gradient in (a) atomic percent Sb per cm.",
|
||
"answer": "-0.02495 at% sb/cm"
|
||
},
|
||
{
|
||
"question": "A 0.2-mm thick wafer of silicon is treated so that a uniform concentration gradient of antimony is produced. One surface contains 1 Sb atom per 10^8 Si atoms and the other surface contains 500 Sb atoms per 10^8 Si atoms. The lattice parameter for Si is 5.407 A. Calculate the concentration gradient in (b) Sb atoms/cm^3·cm.",
|
||
"answer": "-1.246 × 10^19 sb atoms/cm^3·cm"
|
||
}
|
||
]
|
||
处理第 72/832 条数据...
|
||
[
|
||
{
|
||
"question": "When a Cu-Zn alloy solidifies, one portion of the structure contains 25 atomic percent zinc and another portion 0.025 mm away contains 20 atomic percent zinc. The lattice parameter for the FCC alloy is 3.63 x 10^-8 cm. Determine the concentration gradient in (a) atomic percent Zn per cm.",
|
||
"answer": "-2000 at% zn/cm"
|
||
},
|
||
{
|
||
"question": "When a Cu-Zn alloy solidifies, one portion of the structure contains 25 atomic percent zinc and another portion 0.025 mm away contains 20 atomic percent zinc. The lattice parameter for the FCC alloy is 3.63 x 10^-8 cm. Determine the concentration gradient in (b) weight percent Zn per cm.",
|
||
"answer": "-2032 wt% zn/cm"
|
||
}
|
||
]
|
||
处理第 73/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 0.001 -in. BCC iron foil is used to separate a high hydrogen gas from a low hydrogen gas at 650^{\circ} \mathrm{C} .5 \times 10^{8} \mathrm{H} atoms / \mathrm{cm}^{3} are in equilibrium with the hot side of the foil, while 2 \times 10^{3} \mathrm{H} atoms / \mathrm{cm}^{3} are in equilibrium with the cold side. Determine the concentration gradient of hydrogen.",
|
||
"answer": "-1969 \times 10^{8} h atoms/cm^3 \cdot cm"
|
||
},
|
||
{
|
||
"question": "A 0.001 -in. BCC iron foil is used to separate a high hydrogen gas from a low hydrogen gas at 650^{\circ} \mathrm{C} .5 \times 10^{8} \mathrm{H} atoms / \mathrm{cm}^{3} are in equilibrium with the hot side of the foil, while 2 \times 10^{3} \mathrm{H} atoms / \mathrm{cm}^{3} are in equilibrium with the cold side. Determine the flux of hydrogen through the foil.",
|
||
"answer": "0.33 \times 10^{8} h atoms/cm^2 \cdot s"
|
||
}
|
||
]
|
||
API调用错误: Invalid \escape: line 3 column 121 (char 128)
|
||
处理第 74/832 条数据...
|
||
It's a single issue.
|
||
处理第 75/832 条数据...
|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 77/832 条数据...
|
||
It's a single issue.
|
||
处理第 78/832 条数据...
|
||
It's a single issue.
|
||
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|
||
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|
||
处理第 80/832 条数据...
|
||
[
|
||
{
|
||
"question": "Iron containing 0.05 % C is heated to 912 degrees C in an atmosphere that produces 1.20 % C at the surface and is held for 24 h. Calculate the carbon content at 0.05 cm beneath the surface if the iron is BCC.",
|
||
"answer": "For BCC iron, the carbon content at 0.05 cm beneath the surface is 0.95 % C."
|
||
},
|
||
{
|
||
"question": "Iron containing 0.05 % C is heated to 912 degrees C in an atmosphere that produces 1.20 % C at the surface and is held for 24 h. Calculate the carbon content at 0.05 cm beneath the surface if the iron is FCC.",
|
||
"answer": "For FCC iron, the carbon content at 0.05 cm beneath the surface is 0.95 % C."
|
||
}
|
||
]
|
||
处理第 81/832 条数据...
|
||
It's a single issue.
|
||
处理第 82/832 条数据...
|
||
It's a single issue.
|
||
处理第 83/832 条数据...
|
||
It's a single issue.
|
||
处理第 84/832 条数据...
|
||
It's a single issue.
|
||
处理第 85/832 条数据...
|
||
It's a single issue.
|
||
处理第 86/832 条数据...
|
||
It's a single issue.
|
||
处理第 87/832 条数据...
|
||
It's a single issue.
|
||
处理第 88/832 条数据...
|
||
It's a single issue.
|
||
处理第 89/832 条数据...
|
||
It's a single issue.
|
||
处理第 90/832 条数据...
|
||
[
|
||
{
|
||
"question": "A ceramic part made of MgO is sintered successfully at 1700 degrees C in 90 minutes. To minimize thermal stresses during the process, we plan to reduce the temperature to 1500 degrees C. Which will limit the rate at which sintering can be done: diffusion of magnesium ions or diffusion of oxygen ions?",
|
||
"answer": "diffusion of oxygen is the slower of the two, due to the larger ionic radius of the oxygen."
|
||
},
|
||
{
|
||
"question": "A ceramic part made of MgO is sintered successfully at 1700 degrees C in 90 minutes. To minimize thermal stresses during the process, we plan to reduce the temperature to 1500 degrees C. What time will be required at the lower temperature?",
|
||
"answer": "the time required at the lower temperature is 955 min or 15.9 h."
|
||
}
|
||
]
|
||
处理第 91/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A 850-lb force is applied to a 0.15-in. diameter nickel wire having a yield strength of 45,000 psi and a tensile strength of 55,000 psi. Determine whether the wire will plastically deform.",
|
||
"answer": "the wire will plastically deform (48,100 psi)."
|
||
},
|
||
{
|
||
"question": "A 850-lb force is applied to a 0.15-in. diameter nickel wire having a yield strength of 45,000 psi and a tensile strength of 55,000 psi. Determine whether the wire will experience necking.",
|
||
"answer": "no necking will occur (48,100 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 92/832 条数据...
|
||
[
|
||
{
|
||
"question": "A force of 100000 N is applied to a 10 mm × 20 mm iron bar having a yield strength of 400 MPa. Determine whether the bar will plastically deform.",
|
||
"answer": "the bar will plastically deform because the applied stress of 500 MPa exceeds the yield strength of 400 MPa."
|
||
},
|
||
{
|
||
"question": "A force of 100000 N is applied to a 10 mm × 20 mm iron bar having a tensile strength of 480 MPa. Determine whether the bar will experience necking.",
|
||
"answer": "the bar will experience necking because the applied stress of 500 MPa exceeds the tensile strength of 480 MPa."
|
||
}
|
||
]
|
||
处理第 93/832 条数据...
|
||
It's a single issue.
|
||
处理第 94/832 条数据...
|
||
[
|
||
{
|
||
"question": "A force of 20,000 N will cause a 1 cm × 1 cm bar of magnesium to stretch from 10 cm to 10.045 cm. Calculate the modulus of elasticity in GPa.",
|
||
"answer": "the modulus of elasticity is 44.4 GPa."
|
||
},
|
||
{
|
||
"question": "A force of 20,000 N will cause a 1 cm × 1 cm bar of magnesium to stretch from 10 cm to 10.045 cm. Calculate the modulus of elasticity in psi.",
|
||
"answer": "the modulus of elasticity is 6.44 × 10^6 psi."
|
||
}
|
||
]
|
||
处理第 95/832 条数据...
|
||
It's a single issue.
|
||
处理第 96/832 条数据...
|
||
It's a single issue.
|
||
处理第 97/832 条数据...
|
||
It's a single issue.
|
||
处理第 98/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 0.4-in. diameter, 12-in-long titanium bar has a yield strength of 50,000 psi, a modulus of elasticity of 16x10^6 psi, and Poisson's ratio of 0.30. Determine the length of the bar when a 500-lb load is applied.",
|
||
"answer": "the final length of the bar is 12.00298 in."
|
||
},
|
||
{
|
||
"question": "A 0.4-in. diameter, 12-in-long titanium bar has a yield strength of 50,000 psi, a modulus of elasticity of 16x10^6 psi, and Poisson's ratio of 0.30. Determine the diameter of the bar when a 500-lb load is applied.",
|
||
"answer": "the final diameter of the bar is 0.39997 in."
|
||
}
|
||
]
|
||
处理第 99/832 条数据...
|
||
[
|
||
{
|
||
"question": "A three-point bend test is performed on a block of ZrO2 that is 8 in. long, 0.50 in. wide, and 0.25 in. thick and is resting on two supports 4 in. apart. When a force of 400 lb is applied, the specimen deflects 0.037 in. and breaks. Calculate the flexural strength.",
|
||
"answer": "flexural strength = 76,800 psi"
|
||
},
|
||
{
|
||
"question": "A three-point bend test is performed on a block of ZrO2 that is 8 in. long, 0.50 in. wide, and 0.25 in. thick and is resting on two supports 4 in. apart. When a force of 400 lb is applied, the specimen deflects 0.037 in. and breaks. Calculate the flexural modulus, assuming that no plastic deformation occurs.",
|
||
"answer": "flexural modulus = 22.14 x 10^6 psi"
|
||
}
|
||
]
|
||
处理第 100/832 条数据...
|
||
[
|
||
{
|
||
"question": "A three-point bend test is performed on a block of silicon carbide that is 10 cm long, 1.5 cm wide, and 0.6 cm thick and is resting on two supports 7.5 cm apart. The sample breaks when a deflection of 0.09 mm is recorded. Calculate the force that caused the fracture. The flexural modulus for silicon carbide is 480 GPa. Assume that no plastic deformation occurs.",
|
||
"answer": "the force that caused the fracture is 1327 n."
|
||
},
|
||
{
|
||
"question": "A three-point bend test is performed on a block of silicon carbide that is 10 cm long, 1.5 cm wide, and 0.6 cm thick and is resting on two supports 7.5 cm apart. The sample breaks when a deflection of 0.09 mm is recorded. Calculate the flexural strength. The flexural modulus for silicon carbide is 480 GPa. Assume that no plastic deformation occurs.",
|
||
"answer": "the flexural strength is 276 mpa."
|
||
}
|
||
]
|
||
处理第 101/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A thermosetting polymer containing glass beads is required to deflect 0.5 mm when a force of 500 N is applied. The polymer part is 2 cm wide, 0.5 cm thick, and 10 cm long. If the flexural modulus is 6.9 GPa, determine the minimum distance between the supports.",
|
||
"answer": "the minimum distance between the supports is 41 mm."
|
||
},
|
||
{
|
||
"question": "Will the polymer fracture if its flexural strength is 85 MPa? Assume that no plastic deformation occurs.",
|
||
"answer": "the applied stress is 61.5 MPa, which is less than the flexural strength of 85 MPa; the polymer is not expected to fracture."
|
||
}
|
||
]
|
||
```
|
||
处理第 102/832 条数据...
|
||
It's a single issue.
|
||
处理第 103/832 条数据...
|
||
It's a single issue.
|
||
处理第 104/832 条数据...
|
||
It's a single issue.
|
||
处理第 105/832 条数据...
|
||
It's a single issue.
|
||
处理第 106/832 条数据...
|
||
It's a single issue.
|
||
处理第 107/832 条数据...
|
||
It's a single issue.
|
||
处理第 108/832 条数据...
|
||
It's a single issue.
|
||
处理第 109/832 条数据...
|
||
[
|
||
{
|
||
"question": "To survive for one million cycles under conditions that provide for equal compressive and tensile stresses, what is the fatigue strength, or maximum stress amplitude, required?",
|
||
"answer": "The fatigue strength at one million cycles is 22 mpa."
|
||
},
|
||
{
|
||
"question": "What are the maximum stress, the minimum stress, and the mean stress on the part during its use under conditions that provide for equal compressive and tensile stresses?",
|
||
"answer": "The maximum stress is +22 mpa, the minimum stress is -22 mpa, and the mean stress is 0 mpa."
|
||
},
|
||
{
|
||
"question": "What effect would the frequency of the stress application have on the fatigue strength, maximum stress, minimum stress, and mean stress?",
|
||
"answer": "A high frequency will cause heating of the polymer. As the temperature of the polymer increases, the fatigue strength will decrease. If the applied stress is not reduced, then the polymer will fail in a shorter time."
|
||
}
|
||
]
|
||
处理第 110/832 条数据...
|
||
It's a single issue.
|
||
处理第 111/832 条数据...
|
||
It's a single issue.
|
||
处理第 112/832 条数据...
|
||
[
|
||
{
|
||
"question": "Using the data in Figure 7-27 for an iron-chromium-nickel alloy, determine the activation energy \(Q_{r}\) for rupture in the temperature range 980 to \(1090^{\circ} \mathrm{C}\).",
|
||
"answer": "the activation energy \(q_{r}\) is \(117,000 \text{ cal/mol}\)."
|
||
},
|
||
{
|
||
"question": "Using the data in Figure 7-27 for an iron-chromium-nickel alloy, determine the constant \(m\) for rupture in the temperature range 980 to \(1090^{\circ} \mathrm{C}\).",
|
||
"answer": "the constant \(m\) for rupture is \(3.9\)."
|
||
}
|
||
]
|
||
API调用错误: Invalid \escape: line 3 column 119 (char 126)
|
||
处理第 113/832 条数据...
|
||
It's a single issue.
|
||
处理第 114/832 条数据...
|
||
It's a single issue.
|
||
处理第 115/832 条数据...
|
||
It's a single issue.
|
||
处理第 116/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Suppose that liquid nickel is undercooled until homogeneous nucleation occurs. Calculate the critical radius of the nucleus required. Assume that the lattice parameter of the solid FCC nickel is 0.356 nm.",
|
||
"answer": "the critical radius of the nucleus required is 6.65 × 10^-8 cm."
|
||
},
|
||
{
|
||
"question": "Suppose that liquid nickel is undercooled until homogeneous nucleation occurs. Calculate the number of nickel atoms in the nucleus. Assume that the lattice parameter of the solid FCC nickel is 0.356 nm.",
|
||
"answer": "the number of nickel atoms in the nucleus is 109 atoms."
|
||
}
|
||
]
|
||
```
|
||
处理第 117/832 条数据...
|
||
[
|
||
{
|
||
"question": "Suppose that liquid iron is undercooled until homogeneous nucleation occurs. Calculate the critical radius of the nucleus required. Assume that the lattice parameter of the solid BCC iron is 2.92 Å.",
|
||
"answer": "10.128 × 10⁻⁸ cm"
|
||
},
|
||
{
|
||
"question": "Suppose that liquid iron is undercooled until homogeneous nucleation occurs. Calculate the number of iron atoms in the nucleus. Assume that the lattice parameter of the solid BCC iron is 2.92 Å.",
|
||
"answer": "350 atoms"
|
||
}
|
||
]
|
||
处理第 118/832 条数据...
|
||
It's a single issue.
|
||
处理第 119/832 条数据...
|
||
It's a single issue.
|
||
处理第 120/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when iron nucleates at 10 degrees Celsius undercooling. The specific heat of iron is 5.78 J/cm^3·°C.",
|
||
"answer": "0.0333"
|
||
},
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when iron nucleates at 100 degrees Celsius undercooling. The specific heat of iron is 5.78 J/cm^3·°C.",
|
||
"answer": "0.333"
|
||
},
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when iron nucleates homogeneously. The specific heat of iron is 5.78 J/cm^3·°C.",
|
||
"answer": "all dendritically."
|
||
}
|
||
]
|
||
```
|
||
处理第 121/832 条数据...
|
||
[
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when silver nucleates at 10 degrees Celsius undercooling. The specific heat of silver is 3.25 J/cm^3·°C.",
|
||
"answer": "0.0237"
|
||
},
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when silver nucleates at 100 degrees Celsius undercooling. The specific heat of silver is 3.25 J/cm^3·°C.",
|
||
"answer": "0.337"
|
||
},
|
||
{
|
||
"question": "Calculate the fraction of solidification that occurs dendritically when silver nucleates homogeneously. The specific heat of silver is 3.25 J/cm^3·°C.",
|
||
"answer": "0.842"
|
||
}
|
||
]
|
||
处理第 122/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A 2-in. cube solidifies in 4.6 min. Calculate (a) the mold constant in Chvorinov's rule. Assume that n=2.",
|
||
"answer": "the mold constant in chvorinov's rule is 41.48 min/in^2."
|
||
},
|
||
{
|
||
"question": "A 2-in. cube solidifies in 4.6 min. Calculate (b) the solidification time for a 0.5 in. x 0.5 in. x 6 in. bar cast under the same conditions. Assume that n=2.",
|
||
"answer": "the solidification time for the bar is 0.60 min."
|
||
}
|
||
]
|
||
```
|
||
处理第 123/832 条数据...
|
||
It's a single issue.
|
||
处理第 124/832 条数据...
|
||
[
|
||
{
|
||
"question": "Calculate the diameter of the cylindrical riser required to prevent shrinkage in a 4 in. × 10 in. × 20 in. casting if the H / D of the riser is 1.5.",
|
||
"answer": "the diameter of the riser d ≥ 6.67 in."
|
||
},
|
||
{
|
||
"question": "Calculate the height of the cylindrical riser required to prevent shrinkage in a 4 in. × 10 in. × 20 in. casting if the H / D of the riser is 1.5.",
|
||
"answer": "the height of the riser h ≥ 10 in."
|
||
},
|
||
{
|
||
"question": "Calculate the volume of the cylindrical riser required to prevent shrinkage in a 4 in. × 10 in. × 20 in. casting if the H / D of the riser is 1.5.",
|
||
"answer": "the volume of the riser v ≥ 349 in.^3"
|
||
}
|
||
]
|
||
处理第 125/832 条数据...
|
||
[
|
||
{
|
||
"question": "Calculate the diameter of the cylindrical riser required to prevent shrinkage in a 1 in. x 6 in. x 6 in. casting if the H/D of the riser is 1.0.",
|
||
"answer": "the diameter of the riser must be at least 2.25 in."
|
||
},
|
||
{
|
||
"question": "Calculate the height of the cylindrical riser required to prevent shrinkage in a 1 in. x 6 in. x 6 in. casting if the H/D of the riser is 1.0.",
|
||
"answer": "the height of the riser must be at least 2.25 in."
|
||
},
|
||
{
|
||
"question": "Calculate the volume of the cylindrical riser required to prevent shrinkage in a 1 in. x 6 in. x 6 in. casting if the H/D of the riser is 1.0.",
|
||
"answer": "the volume of the riser must be at least 8.95 in^3."
|
||
}
|
||
]
|
||
处理第 126/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 4-in-diameter sphere of liquid copper is allowed to solidify, producing a spherical shrinkage cavity in the center of the casting. Determine the volume and diameter of the shrinkage cavity in the copper casting.",
|
||
"answer": "shrinkage volume: 1.709 in.^{3}; diameter of shrinkage cavity: 1.30 in."
|
||
},
|
||
{
|
||
"question": "A 4-in-diameter sphere of liquid iron is allowed to solidify, producing a spherical shrinkage cavity in the center of the casting. Determine the volume and diameter of the shrinkage cavity in the iron casting.",
|
||
"answer": "shrinkage volume: 1.139 in.^{3}; diameter of shrinkage cavity: 1.30 in."
|
||
}
|
||
]
|
||
处理第 127/832 条数据...
|
||
It's a single issue.
|
||
处理第 128/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 2 cm x 4 cm x 6 cm magnesium casting is produced. After cooling to room temperature, what is the volume of the shrinkage cavity at the center of the casting?",
|
||
"answer": "the volume of the shrinkage cavity at the center of the casting is 46.03 cm3."
|
||
},
|
||
{
|
||
"question": "A 2 cm x 4 cm x 6 cm magnesium casting is produced. After cooling to room temperature, what is the percent shrinkage that must have occurred during solidification?",
|
||
"answer": "the percent shrinkage that must have occurred during solidification is 4.1%."
|
||
}
|
||
]
|
||
处理第 129/832 条数据...
|
||
[
|
||
{
|
||
"question": "A 2 in. × 8 in. × 10 in. iron casting is produced and, after cooling to room temperature, is found to weigh 43.9 lb. Determine the percent shrinkage that must have occurred during solidification.",
|
||
"answer": "The percent shrinkage that must have occurred during solidification is 3.4%."
|
||
},
|
||
{
|
||
"question": "A 2 in. × 8 in. × 10 in. iron casting is produced and, after cooling to room temperature, is found to weigh 43.9 lb. Determine the number of shrinkage pores in the casting if all of the shrinkage occurs as pores with a diameter of 0.05 in.",
|
||
"answer": "The number of shrinkage pores in the casting is 83,354 pores."
|
||
}
|
||
]
|
||
处理第 130/832 条数据...
|
||
It's a single issue.
|
||
处理第 131/832 条数据...
|
||
[
|
||
{
|
||
"question": "A liquid cast iron has a density of 7.65 g/cm3. Immediately after solidification, the density of the solid cast iron is found to be 7.71 g/cm3. Determine the percent volume change that occurs during solidification.",
|
||
"answer": "the percent volume change during solidification is 0.77%."
|
||
},
|
||
{
|
||
"question": "Does the cast iron expand or contract during solidification?",
|
||
"answer": "the cast iron contracts during solidification."
|
||
}
|
||
]
|
||
处理第 132/832 条数据...
|
||
It's a single issue.
|
||
处理第 133/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Au-Ag be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "Yes"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Al-Cu be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "No"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Al-Au be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "No"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system U-W be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "No"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Mo-Ta be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "Yes"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Nb-W be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "No"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Mg-Zn be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "No"
|
||
},
|
||
{
|
||
"question": "Based on Hume-Rothery's conditions, would the system Mg-Cd be expected to display unlimited solid solubility? Explain.",
|
||
"answer": "Yes"
|
||
}
|
||
]
|
||
```
|
||
处理第 134/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Suppose 1 at% of the following elements is added to copper (forming a separate alloy with each element) without exceeding the solubility limit. Which one would be expected to give the higher strength alloy? For copper: r_Cu=1.278 Å (a) Au: r=1.442, φr=+12.8% (b) Mn: r=1.12, φr=-12.4% (c) Sr: r=2.151, φr=+68.3% (d) Si: r=1.176, φr=-8.0% (e) Co: r=1.253, φr=-2.0%",
|
||
"answer": "The Cu-Sr alloy would be expected to be strongest (largest size difference)."
|
||
},
|
||
{
|
||
"question": "Is any of the alloying elements expected to have unlimited solid solubility in copper? For copper: r_Cu=1.278 Å (a) Au: r=1.442, φr=+12.8% (b) Mn: r=1.12, φr=-12.4% (c) Sr: r=2.151, φr=+68.3% (d) Si: r=1.176, φr=-8.0% (e) Co: r=1.253, φr=-2.0%",
|
||
"answer": "The Cu-Au alloy satisfies Hume-Rothery's conditions and might be expected to display complete solid solubility-in fact it freezes like an isomorphous series of alloys, but a number of solid-state transformations occur at lower temperatures."
|
||
}
|
||
]
|
||
```
|
||
处理第 135/832 条数据...
|
||
It's a single issue.
|
||
处理第 136/832 条数据...
|
||
It's a single issue.
|
||
处理第 137/832 条数据...
|
||
It's a single issue.
|
||
处理第 138/832 条数据...
|
||
It's a single issue.
|
||
处理第 139/832 条数据...
|
||
It's a single issue.
|
||
处理第 140/832 条数据...
|
||
It's a single issue.
|
||
处理第 141/832 条数据...
|
||
[
|
||
{
|
||
"question": "A Nb-W alloy held at 2800°C is partly liquid and partly solid. If possible, determine the composition of each phase in the alloy.",
|
||
"answer": "l: 49% w; α: 70% w"
|
||
},
|
||
{
|
||
"question": "A Nb-W alloy held at 2800°C is partly liquid and partly solid. If possible, determine the amount of each phase in the alloy.",
|
||
"answer": "not possible unless we know the original composition of the alloy."
|
||
}
|
||
]
|
||
处理第 142/832 条数据...
|
||
[
|
||
{
|
||
"question": "A Nb-W alloy contains 55% α at 2600°C. Determine the composition of each phase.",
|
||
"answer": "l: 22% w; α: 42% w"
|
||
},
|
||
{
|
||
"question": "A Nb-W alloy contains 55% α at 2600°C. Determine the original composition of the alloy.",
|
||
"answer": "33% w"
|
||
}
|
||
]
|
||
处理第 143/832 条数据...
|
||
[
|
||
{
|
||
"question": "Suppose a 1200-lb bath of a Nb-40 wt % W alloy is held at 2800 degrees C. How many pounds of tungsten can be added to the bath before any solid forms?",
|
||
"answer": "212 additional pounds of W must be added before any solid forms."
|
||
},
|
||
{
|
||
"question": "Suppose a 1200-lb bath of a Nb-40 wt % W alloy is held at 2800 degrees C. How many pounds of tungsten must be added to cause the entire bath to be solid?",
|
||
"answer": "1200 additional pounds of W must be added to cause the entire bath to be solid."
|
||
}
|
||
]
|
||
处理第 144/832 条数据...
|
||
It's a single issue.
|
||
处理第 145/832 条数据...
|
||
[
|
||
{
|
||
"question": "A NiO-60 mol% MgO ceramic is allowed to solidify. Determine the composition of the first solid to form under equilibrium conditions.",
|
||
"answer": "80% mgo"
|
||
},
|
||
{
|
||
"question": "A NiO-60 mol% MgO ceramic is allowed to solidify. Determine the composition of the last liquid to solidify under equilibrium conditions.",
|
||
"answer": "35% mgo"
|
||
}
|
||
]
|
||
处理第 146/832 条数据...
|
||
[
|
||
{
|
||
"question": "A Nb-35% W alloy is allowed to solidify. Determine the composition of the first solid to form under equilibrium conditions.",
|
||
"answer": "55% w"
|
||
},
|
||
{
|
||
"question": "A Nb-35% W alloy is allowed to solidify. Determine the composition of the last liquid to solidify under equilibrium conditions.",
|
||
"answer": "18% w"
|
||
}
|
||
]
|
||
处理第 147/832 条数据...
|
||
It's a single issue.
|
||
处理第 148/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider a Pb-15% Sn alloy. During solidification, determine the composition of the first solid to form.",
|
||
"answer": "8%Sn"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-15% Sn alloy. During solidification, determine the liquidus temperature, solidus temperature, solvus temperature, and freezing range of the alloy.",
|
||
"answer": "liquidus temperature =290 c, solidus temperature =240 c, solvus temperature =170 c, freezing range =50 c"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-15% Sn alloy. During solidification, determine the amounts and compositions of each phase at 260 c.",
|
||
"answer": "l: 30% sn, α: 12% sn; % l=17%, % α=83%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-15% Sn alloy. During solidification, determine the amounts and compositions of each phase at 183 c.",
|
||
"answer": "α: 15% sn; 100% α"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-15% Sn alloy. During solidification, determine the amounts and compositions of each phase at 25 c.",
|
||
"answer": "α: 2% pb, β: 100% sn; % α=87%, % β=13%"
|
||
}
|
||
]
|
||
```
|
||
处理第 149/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine if the alloy is hypoeutectic or hypereutectic.",
|
||
"answer": "hypoeutectic"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine the composition of the first solid to form during solidification.",
|
||
"answer": "14% sn"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine the amounts and compositions of each phase at 184°C.",
|
||
"answer": "α: 19% sn, l: 61.9% sn, % α = 63%, % l = 37%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine the amounts and compositions of each base at 182°C.",
|
||
"answer": "α: 19% sn, β: 97.5% sn, % α = 80%, % β = 20%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine the amounts and compositions of each microconstituent at 182°C.",
|
||
"answer": "primary α: 19% sn, % primary α = 63%, eutectic: 61.9% sn, % eutectic = 37%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-35% Sn alloy. Determine the amounts and compositions of each phase at 25°C.",
|
||
"answer": "α: 2% sn, β: 100% sn, % α = 66%, % β = 34%"
|
||
}
|
||
]
|
||
```
|
||
处理第 150/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine if the alloy is hypoeutectic or hypereutectic.",
|
||
"answer": "hypereutectic"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine the composition of the first solid to form during solidification.",
|
||
"answer": "98% sn"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine the amounts and compositions of each phase at 184 degrees C.",
|
||
"answer": "beta: 97.5% sn, l: 61.9% sn, % beta = 22.8%, % l = 77.2%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine the amounts and compositions of each phase at 182 degrees C.",
|
||
"answer": "alpha: 19% sn, beta: 97.5% sn, % alpha = 35%, % beta = 65%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine the amounts and compositions of each microconstituent at 182 degrees C.",
|
||
"answer": "primary beta: 97.5% sn, % primary beta = 22.8%, eutectic: 61.9% sn, % eutectic = 77.2%"
|
||
},
|
||
{
|
||
"question": "Consider a Pb-70% Sn alloy. Determine the amounts and compositions of each phase at 25 degrees C.",
|
||
"answer": "alpha: 2% sn, beta: 100% sn, % alpha = 30%, % beta = 70%"
|
||
}
|
||
]
|
||
```
|
||
处理第 151/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine if the alloy is hypo eutectic or hyper eutectic.",
|
||
"answer": "hypo eutectic"
|
||
},
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine the composition of the first solid to form during solidification.",
|
||
"answer": "1% si"
|
||
},
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine the amounts and compositions of each phase at 578 degrees C.",
|
||
"answer": "alpha: 1.65% si, l: 12.6% si, % alpha=78.5%, % l=21.5%"
|
||
},
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine the amounts and compositions of each phase at 576 degrees C.",
|
||
"answer": "alpha: 1.65% si, beta: 99.83% si, % alpha=97.6%, % beta=2.4%"
|
||
},
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine the amounts and compositions of each microconstituent at 576 degrees C.",
|
||
"answer": "primary alpha: 1.65% si, % primary alpha=78.5%, eutectic: 12.6% si, % eutectic=21.5%"
|
||
},
|
||
{
|
||
"question": "Consider an Al-4% Si alloy. Determine the amounts and compositions of each phase at 25 degrees C.",
|
||
"answer": "alpha: 0% si, beta: 100% si, % alpha=96%, % beta=4%"
|
||
}
|
||
]
|
||
```
|
||
处理第 152/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine if the alloy is hypo eutectic or hyper eutectic.",
|
||
"answer": "hyper eutectic"
|
||
},
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine the composition of the first solid to form during solidified.",
|
||
"answer": "100% si"
|
||
},
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine the amounts and compositions of each phase at 578 degrees C.",
|
||
"answer": "β: 99.83% si, l: 12.6% si, %l: 85.8%, %β: 14.2%"
|
||
},
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine the amounts and compositions of each phase at 576 degrees C.",
|
||
"answer": "α: 1.65% si, β: 99.83% si, %α: 76.2%, %β: 23.8%"
|
||
},
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine the amounts and compositions of each microconstituent at 576 degrees C.",
|
||
"answer": "primary β: 99.83% si, % primary β: 14.2%; eutectic: 12.6% si, % eutectic: 85.8%"
|
||
},
|
||
{
|
||
"question": "Consider a Al-25% Si alloy. Determine the amounts and compositions of each phase at 25 degrees C.",
|
||
"answer": "α: 0% si, β: 100% si, %α: 75%, %β: 25%"
|
||
}
|
||
]
|
||
```
|
||
处理第 153/832 条数据...
|
||
[
|
||
{
|
||
"question": "A Pb-Sn alloy contains 45% alpha and 55% beta at 100C. Determine the composition of the alloy.",
|
||
"answer": "56.15% sn"
|
||
},
|
||
{
|
||
"question": "Is the alloy hypoeutectic or hypereutectic?",
|
||
"answer": "hypoeutectic"
|
||
}
|
||
]
|
||
处理第 154/832 条数据...
|
||
[
|
||
{
|
||
"question": "An Al-Si alloy contains 85 % α and 15 % β at 500°C. Determine the composition of the alloy.",
|
||
"answer": "15.85% Si"
|
||
},
|
||
{
|
||
"question": "Is the alloy hypoeutectic or hypereutectic?",
|
||
"answer": "hypereutectic"
|
||
}
|
||
]
|
||
处理第 155/832 条数据...
|
||
It's a single issue.
|
||
处理第 156/832 条数据...
|
||
It's a single issue.
|
||
处理第 157/832 条数据...
|
||
[
|
||
{
|
||
"question": "Observation of a microstructure shows that there is 28% eutectic and 72% primary β in an Al-Li alloy. Determine the composition of the alloy and whether it is hypoeutectic or hypereutectic.",
|
||
"answer": "17.46% li, hypereutectic"
|
||
},
|
||
{
|
||
"question": "Observation of a microstructure shows that there is 28% eutectic and 72% primary β in an Al-Li alloy. How much α and β are in the eutectic microconstituent?",
|
||
"answer": "% α_est = 64% and % β_est = 36%"
|
||
}
|
||
]
|
||
处理第 158/832 条数据...
|
||
[
|
||
{
|
||
"question": "Calculate the total amount of alpha and beta in a Pb-50% Sn alloy at 182°C.",
|
||
"answer": "total amount of alpha = 60.5%, beta = 39.5%."
|
||
},
|
||
{
|
||
"question": "Calculate the amount of each microconstituent in a Pb-50% Sn alloy at 182°C.",
|
||
"answer": "microconstituents: primary alpha = 27.7%, eutectic = 72.3%."
|
||
},
|
||
{
|
||
"question": "What fraction of the total alpha in the alloy is contained in the eutectic microconstituent?",
|
||
"answer": "fraction of total alpha in the eutectic microconstituent f = 0.54."
|
||
}
|
||
]
|
||
处理第 159/832 条数据...
|
||
[
|
||
{
|
||
"question": "Recommend an artificial age-hardening heat treatment for a Cu-1.2% Be alloy (see Figure 12-34). Include appropriate temperatures.",
|
||
"answer": "For the Cu-1.2% Be alloy, solution treat between 530°C and 870°C (typical at 780°C), quench, and age below 530°C (typical at 330°C)."
|
||
},
|
||
{
|
||
"question": "Compare the amount of the γ2 precipitate that forms by artificial aging at 400°C with the amount of the precipitate that forms by natural aging for a Cu-1.2% Be alloy.",
|
||
"answer": "The amount of γ2 precipitate at 400°C is 5.4%, and at room temperature, it is 8.5%."
|
||
}
|
||
]
|
||
处理第 160/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For an Fe-0.35% C alloy, determine the temperature at which austenite first begins to transform on cooling.",
|
||
"answer": "795°C"
|
||
},
|
||
{
|
||
"question": "For an Fe-0.35% C alloy, determine the primary microconstituent that forms.",
|
||
"answer": "primary α-ferrite"
|
||
},
|
||
{
|
||
"question": "For an Fe-0.35% C alloy, determine the composition and amount of each phase present at 728°C.",
|
||
"answer": "α: 0.0218% C, 56.1% γ: 0.77% C, 43.9%"
|
||
},
|
||
{
|
||
"question": "For an Fe-0.35% C alloy, determine the composition and amount of each phase present at 726°C.",
|
||
"answer": "α: 0.0218% C, 93.3% Fe3C: 6.67% C, 4.9%"
|
||
},
|
||
{
|
||
"question": "For an Fe-0.35% C alloy, determine the composition and amount of each microconstituent present at 726°C.",
|
||
"answer": "primary α: 0.0218% C, 56.1% pearlite: 0.77% C, 43.9%"
|
||
}
|
||
]
|
||
```
|
||
处理第 161/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For an Fe-1.15% C alloy, determine the temperature at which austenite first begins to transform on cooling.",
|
||
"answer": "880 degrees c"
|
||
},
|
||
{
|
||
"question": "For an Fe-1.15% C alloy, determine the primary microconstituent that forms.",
|
||
"answer": "primary Fe3C"
|
||
},
|
||
{
|
||
"question": "For an Fe-1.15% C alloy, determine the composition and amount of each phase present at 728 degrees C.",
|
||
"answer": "Fe3C: 6.67% C, 6.4%; gamma: 0.77% C, 93.6%"
|
||
},
|
||
{
|
||
"question": "For an Fe-1.15% C alloy, determine the composition and amount of each phase present at 720 degrees C.",
|
||
"answer": "alpha: 0.0218% C, 83%; Fe3C: 6.67% C, 17%"
|
||
},
|
||
{
|
||
"question": "For an Fe-1.15% C alloy, determine the composition and amount of each microconstituent present at 726 degrees C.",
|
||
"answer": "primary Fe3C: 6.67% C, 6.4%; pearlite: 0.77% C, 93.6%"
|
||
}
|
||
]
|
||
```
|
||
处理第 162/832 条数据...
|
||
[
|
||
{
|
||
"question": "A steel contains 8 % cementite and 92 % ferrite at room temperature. Estimate the carbon content of the steel.",
|
||
"answer": "the carbon content of the steel is 0.53 % c."
|
||
},
|
||
{
|
||
"question": "Is the steel hypoeutectoid or hypereutectoid?",
|
||
"answer": "the steel is hypoeutectoid."
|
||
}
|
||
]
|
||
处理第 163/832 条数据...
|
||
[
|
||
{
|
||
"question": "A steel contains 18 % cementite and 82 % ferrite at room temperature. Estimate the carbon content of the steel.",
|
||
"answer": "the carbon content of the steel is 1.20 % c."
|
||
},
|
||
{
|
||
"question": "Is the steel hypoeutectoid or hypereutectoid?",
|
||
"answer": "the steel is hypereutectoid."
|
||
}
|
||
]
|
||
处理第 164/832 条数据...
|
||
[
|
||
{
|
||
"question": "A steel contains 18 % pearlite and 82 % primary ferrite at room temperature. Estimate the carbon content of the steel.",
|
||
"answer": "the carbon content of the steel is 0.156 %c."
|
||
},
|
||
{
|
||
"question": "Is the steel hypoeutectoid or hypereutectoid?",
|
||
"answer": "the steel is hypoeutectoid."
|
||
}
|
||
]
|
||
处理第 165/832 条数据...
|
||
[
|
||
{
|
||
"question": "A steel contains 94 % pearlite and 6 % primary cementite at room temperature. Estimate the carbon content of the steel.",
|
||
"answer": "the carbon content of the steel is 1.124 % c."
|
||
},
|
||
{
|
||
"question": "Is the steel hypoeutectoid or hypereutectoid?",
|
||
"answer": "the steel is hypereutectoid."
|
||
}
|
||
]
|
||
处理第 166/832 条数据...
|
||
It's a single issue.
|
||
处理第 167/832 条数据...
|
||
It's a single issue.
|
||
处理第 168/832 条数据...
|
||
[
|
||
{
|
||
"question": "A steel is heated until 40% austenite, with a carbon content of 0.5%, forms. Estimate the temperature.",
|
||
"answer": "the temperature is about 760 degrees c."
|
||
},
|
||
{
|
||
"question": "A steel is heated until 40% austenite, with a carbon content of 0.5%, forms. Estimate the overall carbon content of the steel.",
|
||
"answer": "the overall carbon content of the steel is 0.212% c."
|
||
}
|
||
]
|
||
处理第 169/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "An isothermally transformed eutectoid steel is found to have a yield strength of 410 MPa. Estimate the transformation temperature.",
|
||
"answer": "transformation temperature =615 C"
|
||
},
|
||
{
|
||
"question": "An isothermally transformed eutectoid steel is found to have a yield strength of 410 MPa. Estimate the interlamellar spacing in the pearlite.",
|
||
"answer": "1 / lambda=60,000 or lambda=1.67 × 10^-5 cm"
|
||
}
|
||
]
|
||
```
|
||
处理第 170/832 条数据...
|
||
[
|
||
{
|
||
"question": "Determine the required transformation temperature and microconstituent if an eutectoid steel is to have the hardness value HRC 38",
|
||
"answer": "600 degrees C"
|
||
},
|
||
{
|
||
"question": "Determine the required transformation temperature and microconstituent if an eutectoid steel is to have the hardness value HRC 42",
|
||
"answer": "400 degrees C"
|
||
},
|
||
{
|
||
"question": "Determine the required transformation temperature and microconstituent if an eutectoid steel is to have the hardness value HRC 48",
|
||
"answer": "340 degrees C"
|
||
},
|
||
{
|
||
"question": "Determine the required transformation temperature and microconstituent if an eutectoid steel is to have the hardness value HRC 52",
|
||
"answer": "300 degrees C"
|
||
}
|
||
]
|
||
处理第 171/832 条数据...
|
||
It's a single issue.
|
||
处理第 172/832 条数据...
|
||
It's a single issue.
|
||
处理第 173/832 条数据...
|
||
It's a single issue.
|
||
处理第 174/832 条数据...
|
||
It's a single issue.
|
||
处理第 175/832 条数据...
|
||
It's a single issue.
|
||
处理第 176/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the austenitizing temperature required to produce a quenched and tempered eutectoid steel with a HRC hardness of less than 50?",
|
||
"answer": "Austenitize at approximately 75 degrees Celsius."
|
||
},
|
||
{
|
||
"question": "What is the quenching temperature required to produce a quenched and tempered eutectoid steel with a HRC hardness of less than 50?",
|
||
"answer": "Quench to below the M_gamma (less than 130 degrees Celsius)."
|
||
},
|
||
{
|
||
"question": "What is the tempering temperature range required to produce a quenched and tempered eutectoid steel with a HRC hardness of less than 50?",
|
||
"answer": "Temper at a temperature higher than 330 degrees Celsius, but less than 727 degrees Celsius."
|
||
}
|
||
]
|
||
```
|
||
处理第 177/832 条数据...
|
||
It's a single issue.
|
||
处理第 178/832 条数据...
|
||
It's a single issue.
|
||
处理第 179/832 条数据...
|
||
It's a single issue.
|
||
处理第 180/832 条数据...
|
||
It's a single issue.
|
||
处理第 181/832 条数据...
|
||
It's a single issue.
|
||
处理第 182/832 条数据...
|
||
It's a single issue.
|
||
处理第 183/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "The nucleus of an atom contains electrons?",
|
||
"answer": "No, the nucleus of an atom does not contain electrons."
|
||
},
|
||
{
|
||
"question": "The nucleus of an atom contains neutrons?",
|
||
"answer": "Yes, the nucleus of an atom contains neutrons."
|
||
},
|
||
{
|
||
"question": "The nucleus of an atom contains protons?",
|
||
"answer": "Yes, the nucleus of an atom contains protons."
|
||
}
|
||
]
|
||
```
|
||
处理第 184/832 条数据...
|
||
It's a single issue.
|
||
处理第 185/832 条数据...
|
||
It's a single issue.
|
||
处理第 186/832 条数据...
|
||
It's a single issue.
|
||
处理第 187/832 条数据...
|
||
It's a single issue.
|
||
处理第 188/832 条数据...
|
||
It's a single issue.
|
||
处理第 189/832 条数据...
|
||
It's a single issue.
|
||
处理第 190/832 条数据...
|
||
It's a single issue.
|
||
处理第 191/832 条数据...
|
||
It's a single issue.
|
||
处理第 192/832 条数据...
|
||
It's a single issue.
|
||
处理第 193/832 条数据...
|
||
It's a single issue.
|
||
处理第 194/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Calculate % IC of the interatomic bonds for the intermetallic compound TiAl3.",
|
||
"answer": "the percent ionic character is 0 %."
|
||
},
|
||
{
|
||
"question": "(b) On the basis of this result what type of interatomic bonding would you expect to be found in TiAl3 ? - van der Waals - ionic - metallic - covalent",
|
||
"answer": "because the percent ionic character is zero and this intermetallic compound is composed of two metals, the bonding is completely metallic."
|
||
}
|
||
]
|
||
处理第 195/832 条数据...
|
||
It's a single issue.
|
||
处理第 196/832 条数据...
|
||
It's a single issue.
|
||
处理第 197/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Some metal is known to have a cubic unit cell with an edge length of 0.437 nm. In addition, it has a density of 4.37 g/cm3 and an atomic weight of 54.85 g/mol. Determine the crystal structure of the metal.",
|
||
"answer": "The metal has an FCC crystal structure."
|
||
},
|
||
{
|
||
"question": "Some metal is known to have a cubic unit cell with an edge length of 0.437 nm. In addition, it has a density of 4.37 g/cm3 and an atomic weight of 54.85 g/mol. Determine the atomic radius of the metal.",
|
||
"answer": "The metal has an atomic radius of 0.155 nm."
|
||
},
|
||
{
|
||
"question": "Some metal is known to have a cubic unit cell with an edge length of 0.437 nm. In addition, it has a density of 4.37 g/cm3 and an atomic weight of 54.85 g/mol. Indicate the letter of the metal listed in the following table that has these characteristics.",
|
||
"answer": "The metal with these characteristics is metal C, which has an atomic radius of 0.155 nm and an FCC crystal structure."
|
||
}
|
||
]
|
||
```
|
||
处理第 198/832 条数据...
|
||
It's a single issue.
|
||
处理第 199/832 条数据...
|
||
It's a single issue.
|
||
处理第 200/832 条数据...
|
||
It's a single issue.
|
||
处理第 201/832 条数据...
|
||
It's a single issue.
|
||
处理第 202/832 条数据...
|
||
It's a single issue.
|
||
处理第 203/832 条数据...
|
||
It's a single issue.
|
||
处理第 204/832 条数据...
|
||
It's a single issue.
|
||
处理第 205/832 条数据...
|
||
It's a single issue.
|
||
处理第 206/832 条数据...
|
||
It's a single issue.
|
||
处理第 207/832 条数据...
|
||
It's a single issue.
|
||
处理第 208/832 条数据...
|
||
It's a single issue.
|
||
处理第 209/832 条数据...
|
||
It's a single issue.
|
||
处理第 210/832 条数据...
|
||
It's a single issue.
|
||
处理第 211/832 条数据...
|
||
It's a single issue.
|
||
处理第 212/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Polyethylene may be fluorinated by inducing the random substitution of fluorine atoms for hydrogen. For this polymer, determine the concentration of F (in wt %) that must be added if this substitution occurs for 18.6 % of all of the original hydrogen atoms. Atomic weights for several elements are included in the following table: Carbon 12.01 g/mol, Chlorine 35.45 g/mol, Fluorine 19.00 g/mol, Hydrogen 1.008 g/mol, Oxygen 16.00 g/mol.",
|
||
"answer": "the concentration of F that must be added is 18.0 wt %."
|
||
},
|
||
{
|
||
"question": "Polyethylene may be fluorinated by inducing the random substitution of fluorine atoms for hydrogen. For this polymer, determine the concentration of F (in wt %) that must be added to completely fluorinate the material, i.e. to produce polytetrafluoroethylene (PTFE). Atomic weights for several elements are included in the following table: Carbon 12.01 g/mol, Chlorine 35.45 g/mol, Fluorine 19.00 g/mol, Hydrogen 1.008 g/mol, Oxygen 16.00 g/mol.",
|
||
"answer": "the concentration of F required to completely fluorinate the material is 76.0 wt %."
|
||
}
|
||
]
|
||
```
|
||
处理第 213/832 条数据...
|
||
It's a single issue.
|
||
处理第 214/832 条数据...
|
||
It's a single issue.
|
||
处理第 215/832 条数据...
|
||
It's a single issue.
|
||
处理第 216/832 条数据...
|
||
It's a single issue.
|
||
处理第 217/832 条数据...
|
||
It's a single issue.
|
||
处理第 218/832 条数据...
|
||
It's a single issue.
|
||
处理第 219/832 条数据...
|
||
It's a single issue.
|
||
处理第 220/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MnO? Explain your answers for MgO.",
|
||
"answer": "For MgO, the ionic radii of the Mn2+ and Mg2+ are 0.067 nm and 0.072 nm, respectively. Therefore the percentage difference in ionic radii, Δr% is determined as follows: Δr% = (0.072 nm - 0.067 nm) / 0.072 nm × 100 = 6.9%, which value is within the acceptable range for a high degree of solubility."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MnO? Explain your answers for CaO.",
|
||
"answer": "For CaO, the ionic radii of the Mn2+ and Ca2+ are 0.067 nm and 0.100 nm, respectively. Therefore, the percentage difference in ionic radii, Δr% is determined as follows: Δr% = (0.100 nm - 0.067 nm) / 0.100 nm × 100 = 33%. This Δr% value is much larger than the ±15% range, and, therefore, CaO is not expected to experience any appreciable solubility in MnO."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MnO? Explain your answers for BeO.",
|
||
"answer": "For BeO, the ionic radii of the Mn2+ and Be2+ are 0.067 nm and 0.035 nm, respectively. Therefore, the percentage difference in ionic radii, Δr% is determined as follows: Δr% = (0.067 nm - 0.035 nm) / 0.067 nm × 100 = 48%. This Δr% value is much larger than the ±15% range, and, therefore, BeO is not expected to experience any appreciable solubility in MnO."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MnO? Explain your answers for NiO.",
|
||
"answer": "For NiO, the ionic radii of the Mn2+ and Ni2+ are 0.067 nm and 0.069 nm, respectively. Therefore, the percentage difference in ionic radii Δr% is determined as follows: Δr% = (0.069 nm - 0.067 nm) / 0.069 nm × 100 = 3%, which value is, of course, within the acceptable range for a high degree of solubility."
|
||
}
|
||
]
|
||
```
|
||
处理第 221/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of these elements would you expect to form a substitutional solid solution having complete solubility with copper? The elements are: Ni, O, H, Pt, Pd, Co, C, Zn, Ag, Al, Cr, Fe. The criteria for complete solubility are: 1) the difference in atomic radii between Cu and the other element must be less than ±15%, 2) the crystal structures must be the same, 3) the electronegativities must be similar, and 4) the valences should be the same, or nearly the same.",
|
||
"answer": "Ni, Pd, and Pt meet all of the criteria and thus form substitutional solid solutions having complete solubility. At elevated temperatures Co and Fe experience allotropic transformations to the FCC crystal structure, and thus display complete solid solubility at these temperatures."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form a substitutional solid solution of incomplete solubility with copper? The elements are: Pd, Al, Cr, Fe, H, Pt, Ni, Zn, C, Ag, O, Co. The criteria for incomplete solubility are: these metals have either BCC or HCP crystal structures, and/or the difference between their atomic radii and that for Cu are greater than ±15%, and/or have a valence different than 2+.",
|
||
"answer": "Ag, Al, Co, Cr, Fe, and Zn form substitutional solid solutions of incomplete solubility. All these metals have either BCC or HCP crystal structures, and/or the difference between their atomic radii and that for Cu are greater than ±15%, and/or have a valence different than 2+."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form an interstitial solid solution with copper? The elements are: C, Pd, Pt, H, Cr, O, Zn, Ag, Al, Co, Fe, Ni. The criteria for interstitial solid solutions are: these elements have atomic radii that are significantly smaller than the atomic radius of Cu.",
|
||
"answer": "C, H, and O form interstitial solid solutions. These elements have atomic radii that are significantly smaller than the atomic radius of Cu."
|
||
}
|
||
]
|
||
```
|
||
处理第 222/832 条数据...
|
||
It's a single issue.
|
||
处理第 223/832 条数据...
|
||
It's a single issue.
|
||
处理第 224/832 条数据...
|
||
It's a single issue.
|
||
处理第 225/832 条数据...
|
||
It's a single issue.
|
||
处理第 226/832 条数据...
|
||
It's a single issue.
|
||
处理第 227/832 条数据...
|
||
It's a single issue.
|
||
处理第 228/832 条数据...
|
||
It's a single issue.
|
||
处理第 229/832 条数据...
|
||
It's a single issue.
|
||
处理第 230/832 条数据...
|
||
It's a single issue.
|
||
处理第 231/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "If an increased steady-state flow rate of O2 (oxygen molecules per second) to the cornea is desired, is increasing the contact lens thickness likely to be useful? Note: the flow rate is equal to product of the diffusion flux and an area of interest through which diffusion occurs.",
|
||
"answer": "If the contact lens thickness is increased and all other factors are preserved, the concentration gradient decrease and the oxygen diffusion flux should decrease."
|
||
},
|
||
{
|
||
"question": "If an increased steady-state flow rate of O2 (oxygen molecules per second) to the cornea is desired, is increasing the diffusivity of oxygen gas by decreasing the contact lens porosity likely to be useful? Note: the flow rate is equal to product of the diffusion flux and an area of interest through which diffusion occurs.",
|
||
"answer": "If the lens features more voids, we expect the oxygen to permeate the membrane faster since oxygen should be able to transit voids faster than the bulk lens material."
|
||
},
|
||
{
|
||
"question": "If an increased steady-state flow rate of O2 (oxygen molecules per second) to the cornea is desired, is increasing the ambient temperature likely to be useful? Note: the flow rate is equal to product of the diffusion flux and an area of interest through which diffusion occurs.",
|
||
"answer": "Increasing the temperature should increase the diffusivity and therefore increase the diffusion flux and flow rate."
|
||
},
|
||
{
|
||
"question": "If an increased steady-state flow rate of O2 (oxygen molecules per second) to the cornea is desired, is increasing the ambient partial pressure of oxygen gas likely to be useful? Note: the flow rate is equal to product of the diffusion flux and an area of interest through which diffusion occurs.",
|
||
"answer": "Increasing the concentration of oxygen in the ambient environment will increase the concentration gradient, thereby increasing the diffusion flux of oxygen."
|
||
}
|
||
]
|
||
```
|
||
处理第 232/832 条数据...
|
||
It's a single issue.
|
||
处理第 233/832 条数据...
|
||
It's a single issue.
|
||
处理第 234/832 条数据...
|
||
It's a single issue.
|
||
处理第 235/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For a bronze alloy, the stress at which plastic deformation begins is 277 MPa and the modulus of elasticity is 117 GPa. What is the maximum load that may be applied to a specimen having a cross-sectional area of 327 mm^2 without plastic deformation?",
|
||
"answer": "the maximum load that may be applied without plastic deformation is 86,700 N."
|
||
},
|
||
{
|
||
"question": "For a bronze alloy, the stress at which plastic deformation begins is 277 MPa and the modulus of elasticity is 117 GPa. If the original specimen length is 148 mm, what is the maximum length to which it may be stretched without causing plastic deformation?",
|
||
"answer": "the maximum length to which the specimen may be stretched without causing plastic deformation is 131.30 mm."
|
||
}
|
||
]
|
||
```
|
||
处理第 236/832 条数据...
|
||
It's a single issue.
|
||
处理第 237/832 条数据...
|
||
It's a single issue.
|
||
处理第 238/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A cylindrical rod 380 mm (15.0 in.) long and having a diameter of 10.0 mm (0.40 in.), is to be subjected to a tensile load of 24,500 N (5500 lbf). Which of the four metals or alloys listed below will not experience plastic deformation under this load? The materials are: Aluminum alloy (Yield Strength: 255 MPa), Brass alloy (Yield Strength: 345 MPa), Copper (Yield Strength: 250 MPa), Steel alloy (Yield Strength: 450 MPa).",
|
||
"answer": "The materials that will not experience plastic deformation under the load of 24,500 N are the Brass alloy and Steel alloy, as their yield strengths (345 MPa and 450 MPa, respectively) are greater than the applied stress."
|
||
},
|
||
{
|
||
"question": "A cylindrical rod 380 mm (15.0 in.) long and having a diameter of 10.0 mm (0.40 in.), is to be subjected to a tensile load of 24,500 N (5500 lbf). Which of the four metals or alloys listed below will experience an elongation of no more than 0.9 mm (0.035 in.) under this load? The materials are: Aluminum alloy (Modulus of Elasticity: 70 GPa), Brass alloy (Modulus of Elasticity: 100 GPa), Copper (Modulus of Elasticity: 110 GPa), Steel alloy (Modulus of Elasticity: 207 GPa).",
|
||
"answer": "The materials that will experience an elongation of no more than 0.9 mm under the load of 24,500 N are the Brass alloy, Copper, and Steel alloy, as their calculated elongations (0.57 mm, 0.52 mm, and 0.57 mm, respectively) are less than or equal to 0.9 mm."
|
||
},
|
||
{
|
||
"question": "Based on the previous two sub-questions, which of the four metals or alloys listed below are possible candidates for the cylindrical rod that will neither experience plastic deformation nor an elongation of more than 0.9 mm under a tensile load of 24,500 N?",
|
||
"answer": "The only candidate material that satisfies both conditions is the Steel alloy, with an elongation of 0.57 mm."
|
||
}
|
||
]
|
||
```
|
||
处理第 239/832 条数据...
|
||
It's a single issue.
|
||
处理第 240/832 条数据...
|
||
It's a single issue.
|
||
处理第 241/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A three-point transverse bending test is conducted on a cylindrical specimen of aluminum oxide having a reported flexural strength of 390 MPa (56,600 psi). If the specimen radius is 2.5 mm (0.10 in.) and the support point separation distance is 30 mm (1.2 in.), predict whether or not you would expect the specimen to fracture when a load of 620 N (140 lbf) is applied.",
|
||
"answer": "Since the flexural strength for this test is 379 MPa (53,500 psi), which is less than the reported flexural strength of 390 MPa, fracture is not predicted. However, there is some chance of fracture due to variability in material strength."
|
||
},
|
||
{
|
||
"question": "Calculate the value of flexural strength for this test given a cylindrical specimen of aluminum oxide with a radius of 2.5 mm (0.10 in.) and a support point separation distance of 30 mm (1.2 in.) when a load of 620 N (140 lbf) is applied.",
|
||
"answer": "The flexural strength for this test is 379 MPa (53,500 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 242/832 条数据...
|
||
[
|
||
{
|
||
"question": "The flexural strength and associated volume fraction porosity for two specimens of the same ceramic material are as follows: \begin{tabular}{cc} \hline \(\sigma_{\mathrm{fs}}\) (MPa) & \(\mathbf{P}\) \\ \hline 100 & 0.05 \\ 50 & 0.20 \\ \hline \end{tabular} (a) Compute the flexural strength for a completely nonporous specimen of this material.",
|
||
"answer": "the flexural strength for a completely nonporous specimen of this material is 126 mpa."
|
||
},
|
||
{
|
||
"question": "The flexural strength and associated volume fraction porosity for two specimens of the same ceramic material are as follows: \begin{tabular}{cc} \hline \(\sigma_{\mathrm{fs}}\) (MPa) & \(\mathbf{P}\) \\ \hline 100 & 0.05 \\ 50 & 0.20 \\ \hline \end{tabular} (b) Compute the flexural strength for a 0.10 volume fraction porosity.",
|
||
"answer": "the flexural strength for a 0.10 volume fraction porosity is 79.4 mpa."
|
||
}
|
||
]
|
||
API调用错误: Invalid \escape: line 3 column 167 (char 174)
|
||
处理第 243/832 条数据...
|
||
It's a single issue.
|
||
处理第 244/832 条数据...
|
||
It's a single issue.
|
||
处理第 245/832 条数据...
|
||
It's a single issue.
|
||
处理第 246/832 条数据...
|
||
It's a single issue.
|
||
处理第 247/832 条数据...
|
||
It's a single issue.
|
||
处理第 248/832 条数据...
|
||
It's a single issue.
|
||
处理第 249/832 条数据...
|
||
It's a single issue.
|
||
处理第 250/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is some of the internal strain energy relieved?",
|
||
"answer": "Some of the internal strain energy is relieved."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is all of the internal strain energy relieved?",
|
||
"answer": "All of the internal strain energy is not relieved."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is there some reduction in the number of dislocations?",
|
||
"answer": "There is some reduction in the number of dislocations."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is there a significant reduction in the number of dislocations, to approximately the number found in the precold-worked state?",
|
||
"answer": "There is not a significant reduction in the number of dislocations, to approximately the number found in the precold-worked state."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is the electrical conductivity recovered to its precold-worked state?",
|
||
"answer": "The electrical conductivity is recovered to its precold-worked state."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, is the thermal conductivity recovered to its precold-worked state?",
|
||
"answer": "The thermal conductivity is recovered to its precold-worked state."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, does the metal become more ductile, as in its precold-worked state?",
|
||
"answer": "The metal does not become more ductile, as in its precold-worked state."
|
||
},
|
||
{
|
||
"question": "During the recovery of a cold-worked material, are grains with high strains replaced with new, unstrained grains?",
|
||
"answer": "Grains with high strains are not replaced with new, unstrained grains."
|
||
}
|
||
]
|
||
```
|
||
处理第 251/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "During the recrystallization of a cold-worked material, is some of the internal strain energy relieved?",
|
||
"answer": "All of the internal strain energy is relieved."
|
||
},
|
||
{
|
||
"question": "During the recrystallization of a cold-worked material, is there some reduction in the number of dislocations?",
|
||
"answer": "There is significant reduction in the number of dislocations."
|
||
},
|
||
{
|
||
"question": "During the recrystallization of a cold-worked material, does the metal become more ductile, as in its precold-worked state?",
|
||
"answer": "The metal becomes more ductile, as in its precold-worked state."
|
||
},
|
||
{
|
||
"question": "During the recrystallization of a cold-worked material, are grains with high strains replaced with new, unstrained grains?",
|
||
"answer": "Grains with high strains are replaced with new, unstrained grains."
|
||
}
|
||
]
|
||
```
|
||
处理第 252/832 条数据...
|
||
It's a single issue.
|
||
处理第 253/832 条数据...
|
||
It's a single issue.
|
||
处理第 254/832 条数据...
|
||
It's a single issue.
|
||
处理第 255/832 条数据...
|
||
It's a single issue.
|
||
处理第 256/832 条数据...
|
||
It's a single issue.
|
||
处理第 257/832 条数据...
|
||
[
|
||
{
|
||
"question": "Deformation of a semicrystalline polymer by drawing produces which of the following in the direction of drawing?",
|
||
"answer": "Increase in strength in the direction of drawing."
|
||
},
|
||
{
|
||
"question": "Deformation of a semicrystalline polymer by drawing produces which of the following perpendicular to the direction of drawing?",
|
||
"answer": "Decrease in strength perpendicular to the direction of drawing."
|
||
}
|
||
]
|
||
处理第 258/832 条数据...
|
||
It's a single issue.
|
||
处理第 259/832 条数据...
|
||
It's a single issue.
|
||
处理第 260/832 条数据...
|
||
It's a single issue.
|
||
处理第 261/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which kind of fracture (ductile or brittle) is associated with intergranular crack propagation?",
|
||
"answer": "Intergranular fracture is brittle."
|
||
},
|
||
{
|
||
"question": "Which kind of fracture (ductile or brittle) is associated with transgranular crack propagation?",
|
||
"answer": "Transgranular fracture is brittle."
|
||
}
|
||
]
|
||
```
|
||
处理第 262/832 条数据...
|
||
It's a single issue.
|
||
处理第 263/832 条数据...
|
||
It's a single issue.
|
||
处理第 264/832 条数据...
|
||
It's a single issue.
|
||
处理第 265/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Does increasing temperature favor brittle fracture in polymers?",
|
||
"answer": "No, increasing temperature does not favor brittle fracture in polymers."
|
||
},
|
||
{
|
||
"question": "Does increasing strain rate favor brittle fracture in polymers?",
|
||
"answer": "Yes, increasing strain rate favors brittle fracture in polymers."
|
||
},
|
||
{
|
||
"question": "Does the presence of a sharp notch favor brittle fracture in polymers?",
|
||
"answer": "Yes, the presence of a sharp notch favors brittle fracture in polymers."
|
||
},
|
||
{
|
||
"question": "Does decreasing specimen thickness favor brittle fracture in polymers?",
|
||
"answer": "No, decreasing specimen thickness does not favor brittle fracture in polymers."
|
||
}
|
||
]
|
||
```
|
||
处理第 266/832 条数据...
|
||
It's a single issue.
|
||
处理第 267/832 条数据...
|
||
It's a single issue.
|
||
处理第 268/832 条数据...
|
||
It's a single issue.
|
||
处理第 269/832 条数据...
|
||
It's a single issue.
|
||
处理第 270/832 条数据...
|
||
It's a single issue.
|
||
处理第 271/832 条数据...
|
||
It's a single issue.
|
||
处理第 272/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Is solid ductile cast iron (ferrite solid solution + embedded graphite spheres) a two-phase material system?",
|
||
"answer": "Yes, it is a two-phase system because there is a physical boundary beyond the particle level that separates chemically and structurally distinct volumes."
|
||
},
|
||
{
|
||
"question": "Is solid sodium chloride (salt, NaCl) a two-phase material system?",
|
||
"answer": "No, it is a single-phase compound, not a solution. The ratio of the two ions is in a fixed stoichiometry and they adopt an orderly arrangement in the crystal."
|
||
},
|
||
{
|
||
"question": "Is liquid bronze (Cu + Sn liquid solution) a two-phase material system?",
|
||
"answer": "No, it is a liquid solution, and solutions are single-phase by definition."
|
||
},
|
||
{
|
||
"question": "Is solid gray cast iron (ferrite solid solution + embedded graphite flakes) a two-phase material system?",
|
||
"answer": "Yes, it is a two-phase system because there is a physical boundary beyond the particle level that separates chemically and structurally distinct volumes."
|
||
},
|
||
{
|
||
"question": "Is solid aluminum featuring dissolved silicon a two-phase material system?",
|
||
"answer": "No, it is a solid solution since silicon is implied to substitute for aluminum. Solutions are single-phase by definition."
|
||
},
|
||
{
|
||
"question": "Is solid lead-tin solder (a mixture of Pb-rich and Sn-rich solid solutions) a two-phase material system?",
|
||
"answer": "Yes, it is a two-phase system because there is a physical boundary beyond the particle level that separates chemically and structurally distinct volumes."
|
||
},
|
||
{
|
||
"question": "Is partially melted aluminum a two-phase material system?",
|
||
"answer": "No, the physical boundary merely separates volumes that are structurally distinct (crystalline and liquid)."
|
||
},
|
||
{
|
||
"question": "Is frozen water with trapped air bubbles a two-phase material system?",
|
||
"answer": "Yes, it is a two-phase system because there is a physical boundary beyond the particle level that separates chemically and structurally distinct volumes."
|
||
},
|
||
{
|
||
"question": "Is epoxy embedded with carbon fibers a two-phase material system?",
|
||
"answer": "Yes, it is a two-phase system because there is a physical boundary beyond the particle level that separates chemically and structurally distinct volumes."
|
||
}
|
||
]
|
||
```
|
||
处理第 273/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Complete the following statement regarding conditions that must be satisfied in order for a solid solution to exhibit extensive solubility. The solute and host species must have a very [w] sizes. (w = similar, different)",
|
||
"answer": "The solute and host species must have a very similar sizes."
|
||
},
|
||
{
|
||
"question": "Complete the following statement regarding conditions that must be satisfied in order for a solid solution to exhibit extensive solubility. The solute and host species must attempt to pack with [x] crystal structure. (x = a similar (or the same), a different)",
|
||
"answer": "The solute and host species must attempt to pack with a similar (or the same) crystal structure."
|
||
},
|
||
{
|
||
"question": "Complete the following statement regarding conditions that must be satisfied in order for a solid solution to exhibit extensive solubility. The solute and host species must feature [y] valence electron configuration. (y = a similar (or the same), a different)",
|
||
"answer": "The solute and host species must feature a similar (or the same) valence electron configuration."
|
||
},
|
||
{
|
||
"question": "Complete the following statement regarding conditions that must be satisfied in order for a solid solution to exhibit extensive solubility. The solute and host species must feature [z] ability to attract electrons (electronegativity). (z = a similar, a different)",
|
||
"answer": "The solute and host species must feature a similar ability to attract electrons (electronegativity)."
|
||
}
|
||
]
|
||
```
|
||
处理第 274/832 条数据...
|
||
It's a single issue.
|
||
处理第 275/832 条数据...
|
||
It's a single issue.
|
||
处理第 276/832 条数据...
|
||
It's a single issue.
|
||
处理第 277/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of the following kinds of information may be determined with the aid of a phase diagram? The phase(s) present at a specified temperature and composition.",
|
||
"answer": "With the aid of a phase diagram the following may be determined: The phase(s) present at a specified temperature and composition."
|
||
},
|
||
{
|
||
"question": "Which of the following kinds of information may be determined with the aid of a phase diagram? The composition(s) of phase(s) present at a specified temperature and composition.",
|
||
"answer": "With the aid of a phase diagram the following may be determined: The composition(s) of phase(s) present at a specified temperature and composition."
|
||
},
|
||
{
|
||
"question": "Which of the following kinds of information may be determined with the aid of a phase diagram? The fraction(s) of phase(s) present at specified temperature and composition.",
|
||
"answer": "With the aid of a phase diagram the following may be determined: The fraction(s) of phase(s) present at a specified temperature and composition."
|
||
}
|
||
]
|
||
```
|
||
处理第 278/832 条数据...
|
||
It's a single issue.
|
||
处理第 279/832 条数据...
|
||
It's a single issue.
|
||
处理第 280/832 条数据...
|
||
It's a single issue.
|
||
处理第 281/832 条数据...
|
||
It's a single issue.
|
||
处理第 282/832 条数据...
|
||
It's a single issue.
|
||
处理第 283/832 条数据...
|
||
It's a single issue.
|
||
处理第 284/832 条数据...
|
||
It's a single issue.
|
||
处理第 285/832 条数据...
|
||
It's a single issue.
|
||
处理第 286/832 条数据...
|
||
It's a single issue.
|
||
处理第 287/832 条数据...
|
||
It's a single issue.
|
||
处理第 288/832 条数据...
|
||
It's a single issue.
|
||
处理第 289/832 条数据...
|
||
It's a single issue.
|
||
处理第 290/832 条数据...
|
||
It's a single issue.
|
||
处理第 291/832 条数据...
|
||
It's a single issue.
|
||
处理第 292/832 条数据...
|
||
It's a single issue.
|
||
处理第 293/832 条数据...
|
||
It's a single issue.
|
||
处理第 294/832 条数据...
|
||
It's a single issue.
|
||
处理第 295/832 条数据...
|
||
It's a single issue.
|
||
处理第 296/832 条数据...
|
||
It's a single issue.
|
||
处理第 297/832 条数据...
|
||
It's a single issue.
|
||
处理第 298/832 条数据...
|
||
It's a single issue.
|
||
处理第 299/832 条数据...
|
||
It's a single issue.
|
||
处理第 300/832 条数据...
|
||
It's a single issue.
|
||
处理第 301/832 条数据...
|
||
It's a single issue.
|
||
处理第 302/832 条数据...
|
||
It's a single issue.
|
||
处理第 303/832 条数据...
|
||
It's a single issue.
|
||
处理第 304/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Select T/F for the following statement regarding aluminum / aluminum alloys: Aluminum alloys are generally not viable as lightweight structural materials in humid environments because they are highly susceptible to corrosion by water vapor.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "Select T/F for the following statement regarding aluminum / aluminum alloys: Aluminum alloys are generally superior to pure aluminum, in terms of yield strength, because their microstructures often contain precipitate phases that strain the lattice, thereby hardening the alloy relative to pure aluminum.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "Select T/F for the following statement regarding aluminum / aluminum alloys: Aluminum is not very workable at high temperatures in air, in terms of extrusion and rolling, because a non-protective oxide grows and consumes the metal, converting it to a hard and brittle ceramic.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "Select T/F for the following statement regarding aluminum / aluminum alloys: Compared to most other metals, like steel, pure aluminum is very resistant to creep deformation.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "Select T/F for the following statement regarding aluminum / aluminum alloys: The relatively low melting point of aluminum is often considered a significant limitation for structural applications.",
|
||
"answer": "T"
|
||
}
|
||
]
|
||
```
|
||
处理第 305/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "[a] Aluminum alloys are generally viable as lightweight structural materials in humid environments because they are not very susceptible to corrosion by water vapor.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[b] Aluminum is not very workable at high temperatures in air, in terms of extrusion and rolling, because a non-protective oxide grows and consumes the metal, converting it to a hard and brittle ceramic.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[c] Aluminum alloys are generally superior to pure aluminum, in terms of yield strength, because their microstructures often contain precipitate phases that strain the lattice, thereby hardening the alloy relative to pure aluminum.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[d] Compared to other metals, like steel, pure aluminum is very resistant to failure via fatigue.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[e] Aluminum exhibits one of the highest melting points of all metals, which makes it difficult and expensive to cast.",
|
||
"answer": "F"
|
||
}
|
||
]
|
||
```
|
||
处理第 306/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "[a] Copper has a higher elastic modulus than aluminum.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[b] The density of copper is closer to that of aluminum than it is to iron.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[c] Bronze is an alloy of copper and zinc.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[d] Copper and its alloys form a green tarnish over time, consisting of sulfides and carbonates.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[e] Copper is relatively resistant to corrosion by neutral and even mildly basic water, making it useful for freshwater plumbing applications.",
|
||
"answer": "T"
|
||
}
|
||
]
|
||
```
|
||
处理第 307/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Select T / F for the following statement regarding copper & copper alloys: Copper is much more abundant in the earth's crust compared to iron or aluminum.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "Select T / F for the following statement regarding copper & copper alloys: Copper is one of just a few metals that can be found in metallic form in nature.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "Select T / F for the following statement regarding copper & copper alloys: Pure and/or annealed copper is more difficult to machine compared to its work-hardened form or its alloys.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "Select T / F for the following statement regarding copper & copper alloys: Copper is a minor component (by weight) of most brass & bronze alloys.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "Select T / F for the following statement regarding copper & copper alloys: Amongst metals and alloys copper is one of the best conductors of heat.",
|
||
"answer": "T"
|
||
}
|
||
]
|
||
```
|
||
处理第 308/832 条数据...
|
||
[
|
||
{
|
||
"question": "[a] Nickel is majority component (by mass) in certain superalloys such as Waspaloy TM.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[b] Tungsten is the lowest density metal that has structural use.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[c] Tantalum offers extremely good corrosion resistance, especially at low temperatures.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[d] Magnesium metal is very similar to aluminum, in terms of its physical and mechanical properties.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[e] Beryllium metal is commonly used as an alloying agent in copper metal.",
|
||
"answer": "T"
|
||
}
|
||
]
|
||
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|
||
It's a single issue.
|
||
处理第 310/832 条数据...
|
||
It's a single issue.
|
||
处理第 311/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "As the porosity of refractory ceramic bricks increases, what happens to the strength?",
|
||
"answer": "Strength decreases."
|
||
},
|
||
{
|
||
"question": "As the porosity of refractory ceramic bricks increases, what happens to the chemical resistance?",
|
||
"answer": "Chemical resistance decreases."
|
||
},
|
||
{
|
||
"question": "As the porosity of refractory ceramic bricks increases, what happens to the thermal insulation?",
|
||
"answer": "Thermal insulation increases."
|
||
}
|
||
]
|
||
```
|
||
处理第 312/832 条数据...
|
||
It's a single issue.
|
||
处理第 313/832 条数据...
|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 320/832 条数据...
|
||
It's a single issue.
|
||
处理第 321/832 条数据...
|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 323/832 条数据...
|
||
It's a single issue.
|
||
处理第 324/832 条数据...
|
||
It's a single issue.
|
||
处理第 325/832 条数据...
|
||
[
|
||
{
|
||
"question": "[a] Composites are single-phase materials by definition.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[b] The term \"composite\" applies to materials that feature polymeric materials only.",
|
||
"answer": "F"
|
||
},
|
||
{
|
||
"question": "[c] Structural composites are, in general, highly regarded for their specific strengths.",
|
||
"answer": "T"
|
||
},
|
||
{
|
||
"question": "[d] Composites featuring continuous and aligned fibers for reinforcement generally offer properties that are highly isotropic compared to most metals (random polycrystals).",
|
||
"answer": "F"
|
||
}
|
||
]
|
||
处理第 326/832 条数据...
|
||
It's a single issue.
|
||
处理第 327/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Match the fiber type 'Whiskers' with its description.",
|
||
"answer": "Whiskers are single crystals with extremely large length-to-diameter ratios."
|
||
},
|
||
{
|
||
"question": "Match the fiber type 'Fibers' with its description.",
|
||
"answer": "Fibers are polycrystalline or amorphous materials with small diameters."
|
||
},
|
||
{
|
||
"question": "Match the fiber type 'Wires' with its description.",
|
||
"answer": "Wires are large-diameter metals."
|
||
}
|
||
]
|
||
```
|
||
处理第 328/832 条数据...
|
||
It's a single issue.
|
||
处理第 329/832 条数据...
|
||
It's a single issue.
|
||
处理第 330/832 条数据...
|
||
It's a single issue.
|
||
处理第 331/832 条数据...
|
||
It's a single issue.
|
||
处理第 332/832 条数据...
|
||
[
|
||
{
|
||
"question": "Carbon fiber-reinforced composites have relatively high strengths?",
|
||
"answer": "Carbon fiber-reinforced composites have relatively high strengths."
|
||
},
|
||
{
|
||
"question": "Carbon fiber-reinforced composites have relatively high stiffnesses?",
|
||
"answer": "Carbon fiber-reinforced composites have relatively high stiffnesses."
|
||
},
|
||
{
|
||
"question": "Carbon fiber-reinforced composites have high service temperatures (>200 degrees C)?",
|
||
"answer": "Carbon fiber-reinforced composites have high service temperatures (>200 degrees C)."
|
||
}
|
||
]
|
||
处理第 333/832 条数据...
|
||
It's a single issue.
|
||
处理第 334/832 条数据...
|
||
It's a single issue.
|
||
处理第 335/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compared to other ceramic materials, do ceramic-matrix composites have better fracture toughnesses?",
|
||
"answer": "Ceramic-matrix composites have higher fracture toughnesses than other ceramic materials."
|
||
},
|
||
{
|
||
"question": "Compared to other ceramic materials, do ceramic-matrix composites have better oxidation resistance?",
|
||
"answer": "The answer is not provided in the given information."
|
||
},
|
||
{
|
||
"question": "Compared to other ceramic materials, do ceramic-matrix composites have better stability at elevated temperatures?",
|
||
"answer": "The answer is not provided in the given information."
|
||
}
|
||
]
|
||
```
|
||
处理第 336/832 条数据...
|
||
It's a single issue.
|
||
处理第 337/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit high tensile moduli at elevated temperatures?",
|
||
"answer": "Carbon-carbon composites have high tensile moduli at elevated temperatures."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit high tensile strengths at elevated temperatures?",
|
||
"answer": "Carbon-carbon composites have high tensile strengths at elevated temperatures."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit resistance to creep?",
|
||
"answer": "Carbon-carbon composites are highly resistant to creep."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit large fracture toughness values?",
|
||
"answer": "Carbon-carbon composites have large fracture toughness values."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit high thermal conductivities?",
|
||
"answer": "Carbon-carbon composites have high thermal conductivities."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit low coefficients of thermal expansion?",
|
||
"answer": "Carbon-carbon composites have low coefficients of thermal expansion."
|
||
},
|
||
{
|
||
"question": "Do carbon-carbon composites exhibit resistance to oxidation at elevated temperatures?",
|
||
"answer": "The answer does not specify resistance to oxidation at elevated temperatures."
|
||
},
|
||
{
|
||
"question": "Are carbon-carbon composites low cost?",
|
||
"answer": "The answer does not specify low cost."
|
||
}
|
||
]
|
||
```
|
||
处理第 338/832 条数据...
|
||
It's a single issue.
|
||
处理第 339/832 条数据...
|
||
It's a single issue.
|
||
处理第 340/832 条数据...
|
||
It's a single issue.
|
||
处理第 341/832 条数据...
|
||
It's a single issue.
|
||
处理第 342/832 条数据...
|
||
It's a single issue.
|
||
处理第 343/832 条数据...
|
||
It's a single issue.
|
||
处理第 344/832 条数据...
|
||
It's a single issue.
|
||
处理第 345/832 条数据...
|
||
It's a single issue.
|
||
处理第 346/832 条数据...
|
||
It's a single issue.
|
||
处理第 347/832 条数据...
|
||
It's a single issue.
|
||
处理第 348/832 条数据...
|
||
It's a single issue.
|
||
处理第 349/832 条数据...
|
||
It's a single issue.
|
||
处理第 350/832 条数据...
|
||
It's a single issue.
|
||
处理第 351/832 条数据...
|
||
It's a single issue.
|
||
处理第 352/832 条数据...
|
||
It's a single issue.
|
||
处理第 353/832 条数据...
|
||
It's a single issue.
|
||
处理第 354/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of the following characteristics are displayed by soft magnetic materials in terms of hysteresis loop size?",
|
||
"answer": "Soft materials have relatively small relative hysteresis loops."
|
||
},
|
||
{
|
||
"question": "Which of the following characteristics are displayed by soft magnetic materials in terms of magnetization and demagnetization fields?",
|
||
"answer": "Magnetization and demagnetization may be achieved using relatively low applied fields."
|
||
}
|
||
]
|
||
```
|
||
处理第 355/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of the following characteristics are displayed by hard magnetic materials in terms of hysteresis loop size?",
|
||
"answer": "Hard materials have relatively large hysteresis loops."
|
||
},
|
||
{
|
||
"question": "Which of the following characteristics are displayed by hard magnetic materials in terms of magnetization and demagnetization field requirements?",
|
||
"answer": "Magnetization and demagnetization require relatively high applied fields."
|
||
}
|
||
]
|
||
```
|
||
处理第 356/832 条数据...
|
||
It's a single issue.
|
||
处理第 357/832 条数据...
|
||
It's a single issue.
|
||
处理第 358/832 条数据...
|
||
It's a single issue.
|
||
处理第 359/832 条数据...
|
||
[
|
||
{
|
||
"question": "Match the type of light transmission with its description: Transmits light with relative little absorption.",
|
||
"answer": "A transparent material transmits light with relatively little absorption."
|
||
},
|
||
{
|
||
"question": "Match the type of light transmission with its description: Transmits light diffusely.",
|
||
"answer": "A translucent material transmits light diffusely."
|
||
},
|
||
{
|
||
"question": "Match the type of light transmission with its description: Is impervious to light transmission.",
|
||
"answer": "An opaque material is impervious to light transmission."
|
||
}
|
||
]
|
||
处理第 360/832 条数据...
|
||
It's a single issue.
|
||
处理第 361/832 条数据...
|
||
It's a single issue.
|
||
处理第 362/832 条数据...
|
||
It's a single issue.
|
||
处理第 363/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Match the following material types with their light transmission characteristics: Single crystal electrical insulators - Opaque, Translucent, Transparent",
|
||
"answer": "Single crystal electrical insulators are transparent."
|
||
},
|
||
{
|
||
"question": "Match the following material types with their light transmission characteristics: Polycrystalline and nonporous electrical insulators - Translucent, Transparent, Opaque",
|
||
"answer": "Polycrystalline and nonporous electrical insulators are translucent."
|
||
},
|
||
{
|
||
"question": "Match the following material types with their light transmission characteristics: Porous electrical insulators - Transparent, Opaque, Translucent",
|
||
"answer": "Porous electrical insulators are opaque to visible light."
|
||
}
|
||
]
|
||
```
|
||
处理第 364/832 条数据...
|
||
It's a single issue.
|
||
处理第 365/832 条数据...
|
||
It's a single issue.
|
||
处理第 366/832 条数据...
|
||
It's a single issue.
|
||
处理第 367/832 条数据...
|
||
It's a single issue.
|
||
处理第 368/832 条数据...
|
||
It's a single issue.
|
||
处理第 369/832 条数据...
|
||
It's a single issue.
|
||
处理第 370/832 条数据...
|
||
It's a single issue.
|
||
处理第 371/832 条数据...
|
||
It's a single issue.
|
||
处理第 372/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "How many grams are there in one amu of a material?",
|
||
"answer": "1.66 x 10^-24 g/amu"
|
||
},
|
||
{
|
||
"question": "Mole, in the context of this book, is taken in units of gram-mole. On this basis, how many atoms are there in a pound-mole of a substance?",
|
||
"answer": "2.73 x 10^26 atoms/lb-mol"
|
||
}
|
||
]
|
||
```
|
||
处理第 373/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Cite two important quantum-mechanical concepts associated with the Bohr model of the atom.",
|
||
"answer": "Two important quantum-mechanical concepts associated with the Bohr model of the atom are (1) that electrons are particles moving in discrete orbitals, and (2) electron energy is quantized into shells."
|
||
},
|
||
{
|
||
"question": "(b) Cite two important additional refinements that resulted from the wave-mechanical atomic model.",
|
||
"answer": "Two important refinements resulting from the wave-mechanical atomic model are (1) that electron position is described in terms of a probability distribution, and (2) electron energy is quantized into both shells and subshells--each electron is characterized by four quantum numbers."
|
||
}
|
||
]
|
||
处理第 374/832 条数据...
|
||
[
|
||
{
|
||
"question": "Relative to electrons and electron states, what does the n quantum number specify?",
|
||
"answer": "The n quantum number designates the electron shell."
|
||
},
|
||
{
|
||
"question": "Relative to electrons and electron states, what does the l quantum number specify?",
|
||
"answer": "The l quantum number designates the electron subshell."
|
||
},
|
||
{
|
||
"question": "Relative to electrons and electron states, what does the mj quantum number specify?",
|
||
"answer": "The mj quantum number designates the number of electron states in each electron subshell."
|
||
},
|
||
{
|
||
"question": "Relative to electrons and electron states, what does the ms quantum number specify?",
|
||
"answer": "The ms quantum number designates the spin moment on each electron."
|
||
}
|
||
]
|
||
处理第 375/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the L shell (n=2), write the four quantum numbers for all of the electrons and note which correspond to the s and p subshells.",
|
||
"answer": "For the L state, n=2, and eight electron states are possible. Possible l values are 0 and 1, while possible ml values are 0 and ±1; and possible ms values are ±1/2. Therefore, for the s states, the quantum numbers are 200(1/2) and 200(-1/2). For the p states, the quantum numbers are 210(1/2), 210(-1/2), 211(1/2), 211(-1/2), 21(-1)(1/2), and 21(-1)(-1/2)."
|
||
},
|
||
{
|
||
"question": "For the M shell (n=3), write the four quantum numbers for all of the electrons and note which correspond to the s, p, and d subshells.",
|
||
"answer": "For the M state, n=3, and 18 states are possible. Possible l values are 0, 1, and 2; possible ml values are 0, ±1, and ±2; and possible ms values are ±1/2. Therefore, for the s states, the quantum numbers are 300(1/2), 300(-1/2), for the p states they are 310(1/2), 310(-1/2), 311(1/2), 311(-1/2), 31(-1)(1/2), and 31(-1)(-1/2); for the d states they are 320(1/2), 320(-1/2), 321(1/2), 321(-1/2), 32(-1)(1/2), 32(-1)(-1/2), 322(1/2), 322(-1/2), 32(-2)(1/2), and 32(-2)(-1/2)."
|
||
}
|
||
]
|
||
```
|
||
处理第 376/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Give the electron configuration for the ion Fe2+.",
|
||
"answer": "The electron configuration for an Fe2+ ion is 1s2 2s2 2p6 3s2 3p6 3d6."
|
||
},
|
||
{
|
||
"question": "Give the electron configuration for the ion Al3+.",
|
||
"answer": "The electron configuration for an Al3+ ion is 1s2 2s2 2p6."
|
||
},
|
||
{
|
||
"question": "Give the electron configuration for the ion Cu+.",
|
||
"answer": "The electron configuration for a Cu+ ion is 1s2 2s2 2p6 3s2 3p6 3d10."
|
||
},
|
||
{
|
||
"question": "Give the electron configuration for the ion Ba2+.",
|
||
"answer": "The electron configuration for a Ba2+ ion is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6."
|
||
},
|
||
{
|
||
"question": "Give the electron configuration for the ion Br-.",
|
||
"answer": "The electron configuration for a Br- ion is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6."
|
||
},
|
||
{
|
||
"question": "Give the electron configuration for the ion O2-.",
|
||
"answer": "The electron configuration for an O2- ion is 1s2 2s2 2p6."
|
||
}
|
||
]
|
||
```
|
||
处理第 377/832 条数据...
|
||
[
|
||
{
|
||
"question": "The Na+ ion has an electron structure that is identical to which inert gas?",
|
||
"answer": "The Na+ ion has an electron configuration the same as neon."
|
||
},
|
||
{
|
||
"question": "The Cl- ion has an electron structure that is identical to which inert gas?",
|
||
"answer": "The Cl- ion has an electron configuration the same as argon."
|
||
}
|
||
]
|
||
处理第 378/832 条数据...
|
||
It's a single issue.
|
||
处理第 379/832 条数据...
|
||
It's a single issue.
|
||
处理第 380/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{7} 4 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{7} 4 s^{2}\) electron configuration is that of a transition metal because of an incomplete \(d\) subshell."
|
||
},
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6}\) electron configuration is that of an inert gas because of filled \(3 s\) and \(3 p\) subshells."
|
||
},
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{5}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{5}\) electron configuration is that of a halogen because it is one electron deficient from having a filled \(L\) shell."
|
||
},
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\) electron configuration is that of an alkaline earth metal because of two \(s\) electrons."
|
||
},
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{2} 4 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{2} 4 s^{2}\) electron configuration is that of a transition metal because of an incomplete \(d\) subshell."
|
||
},
|
||
{
|
||
"question": "Determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}\) electron configuration is that of an alkali metal because of a single \(s\) electron."
|
||
}
|
||
]
|
||
```
|
||
API调用错误: Invalid \escape: line 3 column 67 (char 74)
|
||
处理第 381/832 条数据...
|
||
[
|
||
{
|
||
"question": "What electron subshell is being filled for the rare earth series of elements on the periodic table?",
|
||
"answer": "The 4 f subshell is being filled for the rare earth series of elements."
|
||
},
|
||
{
|
||
"question": "What electron subshell is being filled for the actinide series?",
|
||
"answer": "The 5 f subshell is being filled for the actinide series of elements."
|
||
}
|
||
]
|
||
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|
||
It's a single issue.
|
||
处理第 383/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly cite the main differences between ionic, covalent, and metallic bonding.",
|
||
"answer": "The main differences between the various forms of primary bonding are: Ionic--there is electrostatic attraction between oppositely charged ions. Covalent--there is electron sharing between two adjacent atoms such that each atom assumes a stable electron configuration. Metallic--the positively charged ion cores are shielded from one another, and also 'glued' together by the sea of valence electrons."
|
||
},
|
||
{
|
||
"question": "State the Pauli exclusion principle.",
|
||
"answer": "The Pauli exclusion principle states that each electron state can hold no more than two electrons, which must have opposite spins."
|
||
}
|
||
]
|
||
处理第 384/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What type(s) of bonding would be expected for brass (a copper-zinc alloy)?",
|
||
"answer": "For brass, the bonding is metallic since it is a metal alloy."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for rubber?",
|
||
"answer": "For rubber, the bonding is covalent with some van der Waals. (Rubber is composed primarily of carbon and hydrogen atoms.)"
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for barium sulfide (BaS)?",
|
||
"answer": "For BaS, the bonding is predominantly ionic (but with some covalent character) on the basis of the relative positions of Ba and S in the periodic table."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for solid xenon?",
|
||
"answer": "For solid xenon, the bonding is van der Waals since xenon is an inert gas."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for bronze?",
|
||
"answer": "For bronze, the bonding is metallic since it is a metal alloy (composed of copper and tin)."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for nylon?",
|
||
"answer": "For nylon, the bonding is covalent with perhaps some van der Waals. (Nylon is composed primarily of carbon and hydrogen.)"
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for aluminum phosphide (AlP)?",
|
||
"answer": "For AlP the bonding is predominantly covalent (but with some ionic character) on the basis of the relative positions of Al and P in the periodic table."
|
||
}
|
||
]
|
||
```
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 391/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For alloy A with atomic weight 77.4 g/mol, density 8.22 g/cm³, and atomic radius 0.125 mm, determine whether its crystal structure is FCC, BCC, or simple cubic and then justify your determination.",
|
||
"answer": "for alloy a, its crystal structure is simple cubic."
|
||
},
|
||
{
|
||
"question": "For alloy B with atomic weight 107.6 g/mol, density 13.42 g/cm³, and atomic radius 0.133 mm, determine whether its crystal structure is FCC, BCC, or simple cubic and then justify your determination.",
|
||
"answer": "for alloy b, its crystal structure is fcc."
|
||
},
|
||
{
|
||
"question": "For alloy C with atomic weight 127.3 g/mol, density 9.23 g/cm³, and atomic radius 0.142 mm, determine whether its crystal structure is FCC, BCC, or simple cubic and then justify your determination.",
|
||
"answer": "for alloy c, its crystal structure is simple cubic."
|
||
}
|
||
]
|
||
```
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 394/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "List the point coordinates of all carbon atoms that occupy the corner positions of the diamond cubic unit cell.",
|
||
"answer": "The coordinates of these atoms are as follows: 000, 100, 110, 010, 001, 101, 111, and 011."
|
||
},
|
||
{
|
||
"question": "List the point coordinates of all carbon atoms that reside on the face-centered positions of the diamond cubic unit cell.",
|
||
"answer": "The coordinates of these atoms are as follows: 1/2 1/2 0, 1/2 1/2 1, 1/2 0 1/2, 0 1/2 1/2, and 1/2 1/2 1/2."
|
||
},
|
||
{
|
||
"question": "List the point coordinates of all carbon atoms that are positioned within the interior of the diamond cubic unit cell.",
|
||
"answer": "The coordinates of these atoms are as follows: 3/4 1/4 1/4, 1/4 3/4 3/4, 1/4 1/4 3/4, and 3/4 3/4 1/4."
|
||
}
|
||
]
|
||
```
|
||
处理第 395/832 条数据...
|
||
It's a single issue.
|
||
处理第 396/832 条数据...
|
||
[
|
||
{
|
||
"question": "Convert the (010) plane into the four-index Miller-Bravais scheme for hexagonal unit cells.",
|
||
"answer": "the (010) plane in the four-index miller-bravais scheme is (01 -1 0)."
|
||
},
|
||
{
|
||
"question": "Convert the (101) plane into the four-index Miller-Bravais scheme for hexagonal unit cells.",
|
||
"answer": "the (101) plane in the four-index miller-bravais scheme is (10 -1 1)."
|
||
}
|
||
]
|
||
处理第 397/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Derive the planar density expression for the HCP (0001) plane in terms of the atomic radius R.",
|
||
"answer": "the planar density expression for the hcp (0001) plane in terms of the atomic radius r is: pd_{0001} = 1 / (2 r^{2} sqrt(3))"
|
||
},
|
||
{
|
||
"question": "(b) Compute the planar density value for this same plane for magnesium.",
|
||
"answer": "the planar density value for the (0001) plane for magnesium is: pd_{0001}(mg) = 1.128 × 10^{19} m^{-2}"
|
||
}
|
||
]
|
||
```
|
||
处理第 398/832 条数据...
|
||
It's a single issue.
|
||
处理第 399/832 条数据...
|
||
[
|
||
{
|
||
"question": "The metal iridium has an FCC crystal structure. If the angle of diffraction for the (220) set of planes occurs at 69.22 degrees (first-order reflection) when monochromatic x-radiation having a wavelength of 0.1542 nm is used, compute the interplanar spacing for this set of planes.",
|
||
"answer": "the interplanar spacing for the (220) set of planes for iridium is 0.1357 nm."
|
||
},
|
||
{
|
||
"question": "The metal iridium has an FCC crystal structure. Given the interplanar spacing for the (220) set of planes is 0.1357 nm, compute the atomic radius for an iridium atom.",
|
||
"answer": "the atomic radius for an iridium atom is 0.1357 nm."
|
||
}
|
||
]
|
||
处理第 400/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of these elements would you expect to form with copper a substitutional solid solution having complete solubility? Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for several elements; for those that are nonmetals, only atomic radii are indicated.",
|
||
"answer": "Ni, Pd, and Pt meet all of the criteria and thus form substitutional solid solutions having complete solubility. At elevated temperatures Co and Fe experience allotropic transformations to the FCC crystal structure, and thus display complete solid solubility at these temperatures."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form with copper a substitutional solid solution of incomplete solubility? Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for several elements; for those that are nonmetals, only atomic radii are indicated.",
|
||
"answer": "Ag, Al, Co, Cr, Fe, and Zn form substitutional solid solutions of incomplete solubility. All these metals have either BCC or HCP crystal structures, and/or the difference between their atomic radii and that for Cu are greater than ±15%, and/or have a valence different than 2+."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form with copper an interstitial solid solution? Below, atomic radius, crystal structure, electronegativity, and the most common valence are tabulated, for several elements; for those that are nonmetals, only atomic radii are indicated.",
|
||
"answer": "C, H, and O form interstitial solid solutions. These elements have atomic radii that are significantly smaller than the atomic radius of Cu."
|
||
}
|
||
]
|
||
```
|
||
处理第 401/832 条数据...
|
||
It's a single issue.
|
||
处理第 402/832 条数据...
|
||
It's a single issue.
|
||
处理第 403/832 条数据...
|
||
It's a single issue.
|
||
处理第 404/832 条数据...
|
||
It's a single issue.
|
||
处理第 405/832 条数据...
|
||
It's a single issue.
|
||
处理第 406/832 条数据...
|
||
It's a single issue.
|
||
处理第 407/832 条数据...
|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
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|
||
It's a single issue.
|
||
处理第 410/832 条数据...
|
||
[
|
||
{
|
||
"question": "For a given material, would you expect the surface energy to be greater than, the same as, or less than the grain boundary energy? Why?",
|
||
"answer": "The surface energy will be greater than the grain boundary energy. For grain boundaries, some atoms on one side of a boundary will bond to atoms on the other side; such is not the case for surface atoms. Therefore, there will be fewer unsatisfied bonds along a grain boundary."
|
||
},
|
||
{
|
||
"question": "The grain boundary energy of a small-angle grain boundary is less than for a high-angle one. Why is this so?",
|
||
"answer": "The small-angle grain boundary energy is lower than for a high-angle one because more atoms bond across the boundary for the small-angle, and, thus, there are fewer unsatisfied bonds."
|
||
}
|
||
]
|
||
处理第 411/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Briefly describe a twin and a twin boundary.",
|
||
"answer": "A twin boundary is an interface such that atoms on one side are located at mirror image positions of those atoms situated on the other boundary side. The region on one side of this boundary is called a twin."
|
||
},
|
||
{
|
||
"question": "(b) Cite the difference between mechanical and annealing twins.",
|
||
"answer": "Mechanical twins are produced as a result of mechanical deformation and generally occur in BCC and HCP metals. Annealing twins form during annealing heat treatments, most often in FCC metals."
|
||
}
|
||
]
|
||
处理第 412/832 条数据...
|
||
It's a single issue.
|
||
处理第 413/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Briefly explain the concept of a driving force.",
|
||
"answer": "The driving force is that which compels a reaction to occur."
|
||
},
|
||
{
|
||
"question": "(b) What is the driving force for steady-state diffusion?",
|
||
"answer": "The driving force for steady-state diffusion is the concentration gradient."
|
||
}
|
||
]
|
||
处理第 414/832 条数据...
|
||
It's a single issue.
|
||
处理第 415/832 条数据...
|
||
It's a single issue.
|
||
处理第 416/832 条数据...
|
||
It's a single issue.
|
||
处理第 417/832 条数据...
|
||
[
|
||
{
|
||
"question": "The diffusion coefficients for iron in nickel are given at two temperatures: 1273 K with D = 9.4 x 10^-16 m^2/s and 1473 K with D = 2.4 x 10^-14 m^2/s. Determine the values of D0 and the activation energy Qd.",
|
||
"answer": "the values are d0 = 2.2 x 10^-5 m^2/s and the activation energy qd = 252,400 j/mol."
|
||
},
|
||
{
|
||
"question": "The diffusion coefficients for iron in nickel are given at two temperatures: 1273 K with D = 9.4 x 10^-16 m^2/s and 1473 K with D = 2.4 x 10^-14 m^2/s. What is the magnitude of D at 1100°C (1373 K)?",
|
||
"answer": "the magnitude of d at 1100°c (1373 k) is 5.4 x 10^-15 m^2/s."
|
||
}
|
||
]
|
||
处理第 418/832 条数据...
|
||
[
|
||
{
|
||
"question": "The diffusion coefficients for silver in copper are given at two temperatures: T(°C) = 650, D(m2/s) = 5.5 × 10^-16 and T(°C) = 900, D(m2/s) = 1.3 × 10^-13. Determine the values of D0 and Qd.",
|
||
"answer": "the values are d0 = 7.5 × 10^-5 m2/s and qd = 196,700 j/mol."
|
||
},
|
||
{
|
||
"question": "The diffusion coefficients for silver in copper are given at two temperatures: T(°C) = 650, D(m2/s) = 5.5 × 10^-16 and T(°C) = 900, D(m2/s) = 1.3 × 10^-13. What is the magnitude of D at 875°C?",
|
||
"answer": "the magnitude of d at 875°c is 8.3 × 10^-14 m2/s."
|
||
}
|
||
]
|
||
处理第 419/832 条数据...
|
||
It's a single issue.
|
||
处理第 420/832 条数据...
|
||
It's a single issue.
|
||
处理第 421/832 条数据...
|
||
[
|
||
{
|
||
"question": "For a bronze alloy, the stress at which plastic deformation begins is 275 MPa (40,000 psi), and the modulus of elasticity is 115 GPa (16.7 x 10^6 psi). What is the maximum load that may be applied to a specimen with a cross-sectional area of 325 mm^2 (0.5 in.^2) without plastic deformation?",
|
||
"answer": "the maximum load that may be applied without plastic deformation is 89,375 n (20,000 lb_f)."
|
||
},
|
||
{
|
||
"question": "For a bronze alloy, the stress at which plastic deformation begins is 275 MPa (40,000 psi), and the modulus of elasticity is 115 GPa (16.7 x 10^6 psi). If the original specimen length is 115 mm (4.5 in.), what is the maximum length to which it may be stretched without causing plastic deformation?",
|
||
"answer": "the maximum length to which the specimen may be stretched without causing plastic deformation is 115.28 mm (4.51 in)."
|
||
}
|
||
]
|
||
处理第 422/832 条数据...
|
||
It's a single issue.
|
||
处理第 423/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compute the elastic modulus for titanium, whose stress-strain behavior may be observed in the 'Tensile Tests' module of Virtual Materials Science and Engineering (VMSE). How does this value compare with that presented in Table 6.1 for the same metal?",
|
||
"answer": "(a) the elastic modulus for titanium is 106.4 gpa, which is in very good agreement with the value of 107 gpa from table 6.1."
|
||
},
|
||
{
|
||
"question": "Compute the elastic modulus for tempered steel, whose stress-strain behavior may be observed in the 'Tensile Tests' module of Virtual Materials Science and Engineering (VMSE). How does this value compare with that presented in Table 6.1 for the same metal?",
|
||
"answer": "(b) the elastic modulus for tempered steel is 204.7 gpa, which is in reasonably good agreement with the value of 207 gpa from table 6.1."
|
||
},
|
||
{
|
||
"question": "Compute the elastic modulus for aluminum, whose stress-strain behavior may be observed in the 'Tensile Tests' module of Virtual Materials Science and Engineering (VMSE). How does this value compare with that presented in Table 6.1 for the same metal?",
|
||
"answer": "(c) the elastic modulus for aluminum is 69.1 gpa, which is in excellent agreement with the value of 69 gpa from table 6.1."
|
||
},
|
||
{
|
||
"question": "Compute the elastic modulus for carbon steel, whose stress-strain behavior may be observed in the 'Tensile Tests' module of Virtual Materials Science and Engineering (VMSE). How does this value compare with that presented in Table 6.1 for the same metal?",
|
||
"answer": "(d) the elastic modulus for carbon steel is 215 gpa, which is in reasonable agreement with the value of 207 gpa from table 6.1."
|
||
}
|
||
]
|
||
```
|
||
处理第 424/832 条数据...
|
||
It's a single issue.
|
||
处理第 425/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A cylindrical rod 100 mm long and having a diameter of 10.0 mm is to be deformed using a tensile load of 27,500 N. It must not experience plastic deformation. Of the materials listed as follows, which are possible candidates? Justify your choice(s).",
|
||
"answer": "Of the alloys listed, the steel alloy is a possible candidate because it meets the criterion of not experiencing plastic deformation."
|
||
},
|
||
{
|
||
"question": "A cylindrical rod 100 mm long and having a diameter of 10.0 mm is to be deformed using a tensile load of 27,500 N. It must not experience a diameter reduction of more than 7.5 x 10^-3 mm. Of the materials listed as follows, which are possible candidates? Justify your choice(s).",
|
||
"answer": "Of the alloys listed, the steel alloy is a possible candidate because it meets the criterion regarding diameter reduction. The titanium alloy is not a candidate as it fails this criterion."
|
||
}
|
||
]
|
||
```
|
||
处理第 426/832 条数据...
|
||
[
|
||
{
|
||
"question": "A cylindrical metal specimen having an original diameter of 12.8 mm (0.505 in.) and gauge length of 50.80 mm (2.000 in.) is pulled in tension until fracture occurs. The diameter at the point of fracture is 6.60 mm (0.260 in.), and the fractured gauge length is 72.14 mm (2.840 in.). Calculate the ductility in terms of percent reduction in area.",
|
||
"answer": "the ductility in terms of percent reduction in area is 73.4%."
|
||
},
|
||
{
|
||
"question": "A cylindrical metal specimen having an original diameter of 12.8 mm (0.505 in.) and gauge length of 50.80 mm (2.000 in.) is pulled in tension until fracture occurs. The diameter at the point of fracture is 6.60 mm (0.260 in.), and the fractured gauge length is 72.14 mm (2.840 in.). Calculate the ductility in terms of percent elongation.",
|
||
"answer": "the ductility in terms of percent elongation is 42%."
|
||
}
|
||
]
|
||
处理第 427/832 条数据...
|
||
It's a single issue.
|
||
处理第 428/832 条数据...
|
||
It's a single issue.
|
||
处理第 429/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "To provide some perspective on the dimensions of atomic defects, consider a metal specimen that has a dislocation density of 10^4 mm^-2. Suppose that all the dislocations in 1000 mm^3 (1 cm^3) were somehow removed and linked end to end. How far (in miles) would this chain extend?",
|
||
"answer": "for a dislocation density of 10^4 mm^-2, the chain would extend 6.2 miles."
|
||
},
|
||
{
|
||
"question": "Now suppose that the density is increased to 10^10 mm^-2 by cold working. What would be the chain length of dislocations in 1000 mm^3 of material?",
|
||
"answer": "for a dislocation density of 10^10 mm^-2, the chain would extend 6.2 x 10^6 miles."
|
||
}
|
||
]
|
||
```
|
||
处理第 430/832 条数据...
|
||
[
|
||
{
|
||
"question": "For edge dislocation, cite the relationship between the direction of the applied shear stress and the direction of dislocation line motion.",
|
||
"answer": "edge dislocation--parallel"
|
||
},
|
||
{
|
||
"question": "For screw dislocation, cite the relationship between the direction of the applied shear stress and the direction of dislocation line motion.",
|
||
"answer": "screw dislocation--perpendicular"
|
||
},
|
||
{
|
||
"question": "For mixed dislocation, cite the relationship between the direction of the applied shear stress and the direction of dislocation line motion.",
|
||
"answer": "mixed dislocation--neither parallel nor perpendicular"
|
||
}
|
||
]
|
||
处理第 431/832 条数据...
|
||
[
|
||
{
|
||
"question": "Define a slip system.",
|
||
"answer": "A slip system is a crystallographic plane, and, within that plane, a direction along which dislocation motion (or slip) occurs."
|
||
},
|
||
{
|
||
"question": "Do all metals have the same slip system? Why or why not?",
|
||
"answer": "All metals do not have the same slip system. The reason for this is that for most metals, the slip system will consist of the most densely packed crystallographic plane, and within that plane the most closely packed direction. This plane and direction will vary from crystal structure to crystal structure."
|
||
}
|
||
]
|
||
处理第 432/832 条数据...
|
||
It's a single issue.
|
||
处理第 433/832 条数据...
|
||
[
|
||
{
|
||
"question": "A single crystal of aluminum is oriented for a tensile test such that its slip plane normal makes an angle of 28.1 degrees with the tensile axis. Three possible slip directions make angles of 62.4 degrees, 72.0 degrees, and 81.1 degrees with the same tensile axis. Which of these three slip directions is most favored?",
|
||
"answer": "the most favored slip direction is at an angle of 62.4 degrees with the tensile axis."
|
||
},
|
||
{
|
||
"question": "A single crystal of aluminum is oriented for a tensile test such that its slip plane normal makes an angle of 28.1 degrees with the tensile axis. The most favored slip direction makes an angle of 62.4 degrees with the tensile axis. If plastic deformation begins at a tensile stress of 1.95 MPa (280 psi), determine the critical resolved shear stress for aluminum.",
|
||
"answer": "the critical resolved shear stress for aluminum is 0.80 mpa (114 psi)."
|
||
}
|
||
]
|
||
处理第 434/832 条数据...
|
||
It's a single issue.
|
||
处理第 435/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the difference between deformation by twinning and deformation by slip relative to mechanism?",
|
||
"answer": "With slip deformation there is no crystallographic reorientation, whereas with twinning there is a reorientation."
|
||
},
|
||
{
|
||
"question": "What is the difference between deformation by twinning and deformation by slip relative to conditions of occurrence?",
|
||
"answer": "For slip, the atomic displacements occur in atomic spacing multiples, whereas for twinning, these displacements may be other than by atomic spacing multiples. Slip occurs in metals having many slip systems, whereas twinning occurs in metals having relatively few slip systems."
|
||
},
|
||
{
|
||
"question": "What is the difference between deformation by twinning and deformation by slip relative to final result?",
|
||
"answer": "Normally slip results in relatively large deformations, whereas only small deformations result for twinning."
|
||
}
|
||
]
|
||
```
|
||
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|
||
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|
||
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|
||
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|
||
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|
||
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|
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|
||
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|
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|
||
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|
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|
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|
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|
||
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|
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|
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|
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|
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|
||
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|
||
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|
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|
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|
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|
||
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|
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|
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|
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|
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|
||
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|
||
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|
||
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|
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|
||
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|
||
处理第 453/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly explain the difference between fatigue striations and beachmarks in terms of size.",
|
||
"answer": "With regard to size, beachmarks are normally of macroscopic dimensions and may be observed with the naked eye; fatigue striations are of microscopic size and it is necessary to observe them using electron microscopy."
|
||
},
|
||
{
|
||
"question": "Briefly explain the difference between fatigue striations and beachmarks in terms of origin.",
|
||
"answer": "With regard to origin, beachmarks result from interruptions in the stress cycles; each fatigue striation corresponds to the advance of a fatigue crack during a single load cycle."
|
||
}
|
||
]
|
||
处理第 454/832 条数据...
|
||
It's a single issue.
|
||
处理第 455/832 条数据...
|
||
[
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for nickel.",
|
||
"answer": "for ni: 418 degrees c (785 degrees f)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for copper.",
|
||
"answer": "for cu: 270 degrees c (518 degrees f)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for iron.",
|
||
"answer": "for fe: 450 degrees c (845 degrees f)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for tungsten.",
|
||
"answer": "for w: 1200 degrees c (2190 degrees f)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for lead.",
|
||
"answer": "for pb: -33 degrees c (-27 degrees f)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for aluminum.",
|
||
"answer": "for al: 100 degrees c (212 degrees f)"
|
||
}
|
||
]
|
||
处理第 456/832 条数据...
|
||
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|
||
处理第 457/832 条数据...
|
||
It's a single issue.
|
||
处理第 458/832 条数据...
|
||
[
|
||
{
|
||
"question": "For alloys of two hypothetical metals A and B, there exist an α, A-rich phase and a β, B-rich phase. From the mass fractions of both phases for two different alloys provided in the table below, (which are at the same temperature), determine the composition of the phase boundary (or solubility limit) for the α phase at this temperature.",
|
||
"answer": "the composition of the phase boundary for the α phase is 90 wt% A-10 wt% B."
|
||
},
|
||
{
|
||
"question": "For alloys of two hypothetical metals A and B, there exist an α, A-rich phase and a β, B-rich phase. From the mass fractions of both phases for two different alloys provided in the table below, (which are at the same temperature), determine the composition of the phase boundary (or solubility limit) for the β phase at this temperature.",
|
||
"answer": "the composition of the phase boundary for the β phase is 20.2 wt% A-79.8 wt% B."
|
||
}
|
||
]
|
||
处理第 459/832 条数据...
|
||
It's a single issue.
|
||
处理第 460/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For 11.20 kg of a magnesium-lead alloy of composition 30 wt% Pb-70 wt% Mg, is it possible, at equilibrium, to have α and Mg2Pb phases having respective masses of 7.39 kg and 3.81 kg?",
|
||
"answer": "yes, it is possible to have a 30 wt% pb-70 wt% mg alloy with masses of 7.39 kg and 3.81 kg for the α and mg2pb phases, respectively."
|
||
},
|
||
{
|
||
"question": "What will be the approximate temperature of the alloy?",
|
||
"answer": "the approximate temperature of the alloy is 190 degrees c."
|
||
}
|
||
]
|
||
```
|
||
处理第 461/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Briefly describe the phenomenon of coring and why it occurs.",
|
||
"answer": "Coring is the phenomenon whereby concentration gradients exist across grains in polycrystalline alloys, with higher concentrations of the component having the lower melting temperature at the grain boundaries. It occurs, during solidification, as a consequence of cooling rates that are too rapid to allow for the maintenance of the equilibrium composition of the solid phase."
|
||
},
|
||
{
|
||
"question": "Cite one undesirable consequence of coring.",
|
||
"answer": "One undesirable consequence of a cored structure is that, upon heating, the grain boundary regions will melt first and at a temperature below the equilibrium phase boundary from the phase diagram; this melting results in a loss in mechanical integrity of the alloy."
|
||
}
|
||
]
|
||
```
|
||
处理第 462/832 条数据...
|
||
It's a single issue.
|
||
处理第 463/832 条数据...
|
||
It's a single issue.
|
||
处理第 464/832 条数据...
|
||
It's a single issue.
|
||
处理第 465/832 条数据...
|
||
It's a single issue.
|
||
处理第 466/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compute the mass fraction of α ferrite in pearlite.",
|
||
"answer": "the mass fraction of α ferrite in pearlite is 0.89."
|
||
},
|
||
{
|
||
"question": "Compute the mass fraction of cementite in pearlite.",
|
||
"answer": "the mass fraction of cementite in pearlite is 0.11."
|
||
}
|
||
]
|
||
处理第 467/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the distinction between hypoeutectoid and hypereutectoid steels?",
|
||
"answer": "A \"hypoeutectoid\" steel has a carbon concentration less than the eutectoid; on the other hand, a \"hypereutectoid\" steel has a carbon content greater than the eutectoid."
|
||
},
|
||
{
|
||
"question": "In a hypoeutectoid steel, both eutectoid and proeutectoid ferrite exist. Explain the difference between them. What will be the carbon concentration in each?",
|
||
"answer": "For a hypoeutectoid steel, the proeutectoid ferrite is a microconstituent that formed above the eutectoid temperature. The eutectoid ferrite is one of the constituents of pearlite that formed at a temperature below the eutectoid. The carbon concentration for both ferrites is 0.022 wt% C."
|
||
}
|
||
]
|
||
```
|
||
处理第 468/832 条数据...
|
||
It's a single issue.
|
||
处理第 469/832 条数据...
|
||
It's a single issue.
|
||
处理第 470/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider 1.0 kg of austenite containing 1.15 wt % C, cooled to below 727 C (1341 F). What is the proeutectoid phase?",
|
||
"answer": "the proeutectoid phase is fe3c."
|
||
},
|
||
{
|
||
"question": "Consider 1.0 kg of austenite containing 1.15 wt % C, cooled to below 727 C (1341 F). How many kilograms each of total ferrite and cementite form?",
|
||
"answer": "the total ferrite formed is 0.83 kg, and the total cementite formed is 0.17 kg."
|
||
},
|
||
{
|
||
"question": "Consider 1.0 kg of austenite containing 1.15 wt % C, cooled to below 727 C (1341 F). How many kilograms each of pearlite and the proeutectoid phase form?",
|
||
"answer": "the pearlite formed is 0.93 kg, and the proeutectoid phase (cementite) formed is 0.07 kg."
|
||
}
|
||
]
|
||
```
|
||
处理第 471/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider 2.5 kg of austenite containing 0.65 wt % C, cooled to below 727 C (1341 F). What is the proeutectoid phase?",
|
||
"answer": "ferrite is the proeutectoid phase."
|
||
},
|
||
{
|
||
"question": "Consider 2.5 kg of austenite containing 0.65 wt % C, cooled to below 727 C (1341 F). How many kilograms each of total ferrite and cementite form?",
|
||
"answer": "the total ferrite formed is 2.27 kg, and the total cementite formed is 0.23 kg."
|
||
},
|
||
{
|
||
"question": "Consider 2.5 kg of austenite containing 0.65 wt % C, cooled to below 727 C (1341 F). How many kilograms each of pearlite and the proeutectoid phase form?",
|
||
"answer": "the pearlite formed is 2.12 kg, and the proeutectoid ferrite formed is 0.38 kg."
|
||
}
|
||
]
|
||
```
|
||
处理第 472/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compute the mass fraction of proeutectoid ferrite that forms in an iron-carbon alloy containing 0.25 wt% C.",
|
||
"answer": "the mass fraction of proeutectoid ferrite is 0.69."
|
||
},
|
||
{
|
||
"question": "Compute the mass fraction of pearlite that forms in an iron-carbon alloy containing 0.25 wt% C.",
|
||
"answer": "the mass fraction of pearlite is 0.31."
|
||
}
|
||
]
|
||
处理第 473/832 条数据...
|
||
It's a single issue.
|
||
处理第 474/832 条数据...
|
||
It's a single issue.
|
||
处理第 475/832 条数据...
|
||
It's a single issue.
|
||
处理第 476/832 条数据...
|
||
[
|
||
{
|
||
"question": "Consider 2.0 kg of a 99.6 wt % Fe-0.4 wt % C alloy that is cooled to a temperature just below the eutectoid. How many kilograms of proeutectoid ferrite form?",
|
||
"answer": "0.98 kg of proeutectoid ferrite forms."
|
||
},
|
||
{
|
||
"question": "Consider 2.0 kg of a 99.6 wt % Fe-0.4 wt % C alloy that is cooled to a temperature just below the eutectoid. How many kilograms of eutectoid ferrite form?",
|
||
"answer": "0.90 kg of eutectoid ferrite forms."
|
||
},
|
||
{
|
||
"question": "Consider 2.0 kg of a 99.6 wt % Fe-0.4 wt % C alloy that is cooled to a temperature just below the eutectoid. How many kilograms of cementite form?",
|
||
"answer": "0.114 kg of cementite forms."
|
||
}
|
||
]
|
||
处理第 477/832 条数据...
|
||
It's a single issue.
|
||
处理第 478/832 条数据...
|
||
It's a single issue.
|
||
处理第 479/832 条数据...
|
||
It's a single issue.
|
||
处理第 480/832 条数据...
|
||
It's a single issue.
|
||
处理第 481/832 条数据...
|
||
[
|
||
{
|
||
"question": "Is it possible to determine the composition of an iron-carbon alloy if the mass fraction of eutectoid cementite is 0.104?",
|
||
"answer": "yes, it is possible to determine the alloy composition, and there are two possible answers."
|
||
},
|
||
{
|
||
"question": "What is the composition of the alloy if eutectoid cementite exists in addition to proeutectoid cementite?",
|
||
"answer": "the alloy composition is 1.11 wt% c."
|
||
},
|
||
{
|
||
"question": "What is the composition of a hypoeutectoid alloy where all cementite is eutectoid cementite and the mass fraction of total cementite is 0.104?",
|
||
"answer": "the composition can be determined using the lever rule."
|
||
}
|
||
]
|
||
处理第 482/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Is it possible to determine the composition of an iron-carbon alloy if the mass fraction of eutectoid ferrite is 0.82?",
|
||
"answer": "yes, it is possible to determine the alloy composition; and, in fact, there are two possible answers."
|
||
},
|
||
{
|
||
"question": "What is the first possible composition of the alloy if the mass fraction of eutectoid ferrite is 0.82?",
|
||
"answer": "for the first case, the composition is c0 = 0.70 wt % c."
|
||
},
|
||
{
|
||
"question": "What is the second possible composition of the alloy if the mass fraction of eutectoid ferrite is 0.82?",
|
||
"answer": "for the second case, the composition is c0 = 1.22 wt % c."
|
||
}
|
||
]
|
||
```
|
||
处理第 483/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the first stage involved in the formation of particles of a new phase? Briefly describe it.",
|
||
"answer": "The first stage is nucleation. The nucleation process involves the formation of normally very small particles of the new phase(s) which are stable and capable of continued growth."
|
||
},
|
||
{
|
||
"question": "What is the second stage involved in the formation of particles of a new phase? Briefly describe it.",
|
||
"answer": "The second stage is growth. The growth stage is simply the increase in size of the new phase particles."
|
||
}
|
||
]
|
||
```
|
||
处理第 484/832 条数据...
|
||
It's a single issue.
|
||
处理第 485/832 条数据...
|
||
It's a single issue.
|
||
处理第 486/832 条数据...
|
||
It's a single issue.
|
||
处理第 487/832 条数据...
|
||
[
|
||
{
|
||
"question": "In terms of heat treatment and the development of microstructure, what is one major limitation of the iron-iron carbide phase diagram related to nonequilibrium phases?",
|
||
"answer": "The nonequilibrium martensite does not appear on the diagram."
|
||
},
|
||
{
|
||
"question": "In terms of heat treatment and the development of microstructure, what is one major limitation of the iron-iron carbide phase diagram related to time-temperature relationships?",
|
||
"answer": "The diagram provides no indication as to the time-temperature relationships for the formation of pearlite, bainite, and spheroidite, all of which are composed of the equilibrium ferrite and cementite phases."
|
||
}
|
||
]
|
||
处理第 488/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly describe the phenomena of superheating and supercooling.",
|
||
"answer": "Superheating and supercooling correspond, respectively, to heating or cooling above or below a phase transition temperature without the occurrence of the transformation."
|
||
},
|
||
{
|
||
"question": "Why do these phenomena occur?",
|
||
"answer": "These phenomena occur because right at the phase transition temperature, the driving force is not sufficient to cause the transformation to occur. The driving force is enhanced during superheating or supercooling."
|
||
}
|
||
]
|
||
处理第 489/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly cite the differences between pearlite, bainite, and spheroidite relative to microstructure.",
|
||
"answer": "The microstructures of pearlite, bainite, and spheroidite all consist of α-ferrite and cementite phases. For pearlite, the two phases exist as layers which alternate with one another. Bainite consists of very fine and parallel needle-shaped particles of cementite that are surrounded an α-ferrite matrix. For spheroidite, the matrix is ferrite, and the cementite phase is in the shape of sphere-shaped particles."
|
||
},
|
||
{
|
||
"question": "Briefly cite the differences between pearlite, bainite, and spheroidite relative to mechanical properties.",
|
||
"answer": "Bainite is harder and stronger than pearlite, which, in turn, is harder and stronger than spheroidite."
|
||
}
|
||
]
|
||
处理第 490/832 条数据...
|
||
It's a single issue.
|
||
处理第 491/832 条数据...
|
||
[
|
||
{
|
||
"question": "Name the microstructural products of eutectoid iron-carbon alloy (0.76 wt% C) specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 200°C/s.",
|
||
"answer": "At a rate of 200°C/s, only martensite forms."
|
||
},
|
||
{
|
||
"question": "Name the microstructural products of eutectoid iron-carbon alloy (0.76 wt% C) specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 100°C/s.",
|
||
"answer": "At a rate of 100°C/s, both martensite and pearlite form."
|
||
},
|
||
{
|
||
"question": "Name the microstructural products of eutectoid iron-carbon alloy (0.76 wt% C) specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 20°C/s.",
|
||
"answer": "At a rate of 20°C/s, only fine pearlite forms."
|
||
}
|
||
]
|
||
处理第 492/832 条数据...
|
||
[
|
||
{
|
||
"question": "What is one important difference between continuous cooling transformation diagrams for plain carbon and alloy steels regarding the presence of a bainite nose?",
|
||
"answer": "For an alloy steel, a bainite nose will be present, which nose will be absent for plain carbon alloys."
|
||
},
|
||
{
|
||
"question": "What is one important difference between continuous cooling transformation diagrams for plain carbon and alloy steels regarding the position of the pearlite-proeutectoid noses?",
|
||
"answer": "The pearlite-proeutectoid noses for plain carbon steel alloys are positioned at shorter times than for the alloy steels."
|
||
}
|
||
]
|
||
处理第 493/832 条数据...
|
||
It's a single issue.
|
||
处理第 494/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Name the microstructural products of 4340 alloy steel specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 10°C/s.",
|
||
"answer": "only martensite forms."
|
||
},
|
||
{
|
||
"question": "Name the microstructural products of 4340 alloy steel specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 1°C/s.",
|
||
"answer": "both martensite and bainite form."
|
||
},
|
||
{
|
||
"question": "Name the microstructural products of 4340 alloy steel specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 0.1°C/s.",
|
||
"answer": "martensite, proeutectoid ferrite, and bainite form."
|
||
},
|
||
{
|
||
"question": "Name the microstructural products of 4340 alloy steel specimens that are first completely transformed to austenite, then cooled to room temperature at a rate of 0.01°C/s.",
|
||
"answer": "martensite, proeutectoid ferrite, pearlite, and bainite form."
|
||
}
|
||
]
|
||
```
|
||
处理第 495/832 条数据...
|
||
It's a single issue.
|
||
处理第 496/832 条数据...
|
||
It's a single issue.
|
||
处理第 497/832 条数据...
|
||
It's a single issue.
|
||
处理第 498/832 条数据...
|
||
It's a single issue.
|
||
处理第 499/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly explain why the hardness of tempered martensite diminishes with tempering time at constant temperature.",
|
||
"answer": "The hardness of tempered martensite diminishes with tempering time at constant temperature because the microstructure consists of small sphere-like particles of cementite embedded within a ferrite matrix. As tempering time increases, the cementite particles grow, which reduces the ferrite-cementite phase boundary area. Since these phase boundaries act as barriers to dislocation motion, the reduction in phase boundary area leads to a decrease in hardness."
|
||
},
|
||
{
|
||
"question": "Briefly explain why the hardness of tempered martensite diminishes with increasing temperature at constant tempering time.",
|
||
"answer": "The hardness of tempered martensite diminishes with increasing temperature at constant tempering time because higher temperatures accelerate the rate of cementite particle growth. This growth reduces the ferrite-cementite phase boundary area, which acts as barriers to dislocation motion. Consequently, the reduction in phase boundary area results in a decrease in hardness."
|
||
}
|
||
]
|
||
处理第 500/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Briefly describe the microstructural difference between spheroidite and tempered martensite.",
|
||
"answer": "Both tempered martensite and spheroidite have sphere-like cementite particles within a ferrite matrix; however, these particles are much larger for spheroidite."
|
||
},
|
||
{
|
||
"question": "Explain why tempered martensite is much harder and stronger.",
|
||
"answer": "Tempered martensite is harder and stronger inasmuch as there is much more ferrite-cementite phase boundary area for the smaller particles; thus, there is greater reinforcement of the ferrite phase, and more phase boundary barriers to dislocation motion."
|
||
}
|
||
]
|
||
```
|
||
处理第 501/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "List the four classifications of steels.",
|
||
"answer": "Low Carbon Steels, Medium Carbon Steels, High Carbon Steels, High Alloy Steels (Stainless and Tool)"
|
||
},
|
||
{
|
||
"question": "For Low Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: nonresponsive to heat treatments; relatively soft and weak; machinable and weldable. Typical applications: automobile bodies, structural shapes, pipelines, buildings, bridges, and tin cans."
|
||
},
|
||
{
|
||
"question": "For Medium Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: heat treatable, relatively large combinations of mechanical characteristics. Typical applications: railway wheels and tracks, gears, crankshafts, and machine parts."
|
||
},
|
||
{
|
||
"question": "For High Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: hard, strong, and relatively brittle. Typical applications: chisels, hammers, knives, and hacksaw blades."
|
||
},
|
||
{
|
||
"question": "For High Alloy Steels (Stainless and Tool), briefly describe the properties and typical applications.",
|
||
"answer": "Properties: hard and wear resistant; resistant to corrosion in a large variety of environments. Typical applications: cutting tools, drills, cutlery, food processing, and surgical tools."
|
||
}
|
||
]
|
||
```
|
||
处理第 502/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Cite three reasons why ferrous alloys are used so extensively.",
|
||
"answer": "Ferrous alloys are used extensively because: (1) Iron ores exist in abundant quantities. (2) Economical extraction, refining, and fabrication techniques are available. (3) The alloys may be tailored to have a wide range of properties."
|
||
},
|
||
{
|
||
"question": "Cite three characteristics of ferrous alloys that limit their utilization.",
|
||
"answer": "Disadvantages of ferrous alloys are: (1) They are susceptible to corrosion. (2) They have a relatively high density. (3) They have relatively low electrical conductivities."
|
||
}
|
||
]
|
||
```
|
||
处理第 503/832 条数据...
|
||
It's a single issue.
|
||
处理第 504/832 条数据...
|
||
It's a single issue.
|
||
处理第 505/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compare white and nodular cast irons with respect to composition and heat treatment.",
|
||
"answer": "White iron--2.5 to 4.0 wt% C and less than 1.0 wt% Si. No heat treatment; however, cooling is rapid during solidification. Nodular cast iron--2.5 to 4.0 wt% C, 1.0 to 3.0 wt% Si, and a small amount of Mg or Ce. A heat treatment at about 700°C may be necessary to produce a ferritic matrix."
|
||
},
|
||
{
|
||
"question": "Compare white and nodular cast irons with respect to microstructure.",
|
||
"answer": "White iron--There are regions of cementite interspersed within pearlite. Nodular cast iron--Nodules of graphite are embedded in a ferrite or pearlite matrix."
|
||
},
|
||
{
|
||
"question": "Compare white and nodular cast irons with respect to mechanical characteristics.",
|
||
"answer": "White iron--Extremely hard and brittle. Nodular cast iron--Moderate strength and ductility."
|
||
}
|
||
]
|
||
```
|
||
处理第 506/832 条数据...
|
||
It's a single issue.
|
||
处理第 507/832 条数据...
|
||
It's a single issue.
|
||
处理第 508/832 条数据...
|
||
It's a single issue.
|
||
处理第 509/832 条数据...
|
||
It's a single issue.
|
||
处理第 510/832 条数据...
|
||
[
|
||
{
|
||
"question": "Cite advantages of cold working.",
|
||
"answer": "The advantages of cold working are: (1) A high quality surface finish. (2) The mechanical properties may be varied. (3) Close dimensional tolerances."
|
||
},
|
||
{
|
||
"question": "Cite disadvantages of cold working.",
|
||
"answer": "The disadvantages of cold working are: (1) High deformation energy requirements. (2) Large deformations must be accomplished in steps, which may be expensive. (3) A loss of ductility."
|
||
},
|
||
{
|
||
"question": "Cite advantages of hot working.",
|
||
"answer": "The advantages of hot working are: (1) Large deformations are possible, which may be repeated. (2) Deformation energy requirements are relatively low."
|
||
},
|
||
{
|
||
"question": "Cite disadvantages of hot working.",
|
||
"answer": "The disadvantages of hot working are: (1) A poor surface finish. (2) A variety of mechanical properties is not possible."
|
||
}
|
||
]
|
||
处理第 511/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Cite advantages of forming metals by extrusion as opposed to rolling.",
|
||
"answer": "The advantages of extrusion as opposed to rolling are as follows: (1) Pieces having more complicated cross-sectional geometries may be formed. (2) Seamless tubing may be produced."
|
||
},
|
||
{
|
||
"question": "Cite some disadvantages of forming metals by extrusion as opposed to rolling.",
|
||
"answer": "The disadvantages of extrusion over rolling are as follows: (1) Nonuniform deformation over the cross-section. (2) A variation in properties may result over a cross-section of an extruded piece."
|
||
}
|
||
]
|
||
```
|
||
处理第 512/832 条数据...
|
||
It's a single issue.
|
||
处理第 513/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compare sand casting technique",
|
||
"answer": "For sand casting, sand is the mold material, a two-piece mold is used, ordinarily the surface finish is not an important consideration, the sand may be reused (but the mold may not), casting rates are low, and large pieces are usually cast."
|
||
},
|
||
{
|
||
"question": "Compare die casting technique",
|
||
"answer": "For die casting, a permanent mold is used, casting rates are high, the molten metal is forced into the mold under pressure, a two-piece mold is used, and small pieces are normally cast."
|
||
},
|
||
{
|
||
"question": "Compare investment casting technique",
|
||
"answer": "For investment casting, a single-piece mold is used, which is not reusable; it results in high dimensional accuracy, good reproduction of detail, and a fine surface finish; and casting rates are low."
|
||
},
|
||
{
|
||
"question": "Compare lost foam casting technique",
|
||
"answer": "For lost foam casting, the pattern is polystyrene foam, whereas the mold material is sand. Complex geometries and tight tolerances are possible. Casting rates are higher than for investment, and there are few environmental wastes."
|
||
},
|
||
{
|
||
"question": "Compare continuous casting technique",
|
||
"answer": "For continuous casting, at the conclusion of the extraction process, the molten metal is cast into a continuous strand having either a rectangular or circular cross-section; these shapes are desirable for subsequent secondary metal-forming operations. The chemical composition and mechanical properties are relatively uniform throughout the cross-section."
|
||
}
|
||
]
|
||
```
|
||
处理第 514/832 条数据...
|
||
It's a single issue.
|
||
处理第 515/832 条数据...
|
||
[
|
||
{
|
||
"question": "Cite three sources of internal residual stresses in metal components.",
|
||
"answer": "Three sources of residual stresses in metal components are plastic deformation processes, nonuniform cooling of a piece that was cooled from an elevated temperature, and a phase transformation in which parent and product phases have different densities."
|
||
},
|
||
{
|
||
"question": "What are two possible adverse consequences of internal residual stresses in metal components?",
|
||
"answer": "Two adverse consequences of these stresses are distortion (or warpage) and fracture."
|
||
}
|
||
]
|
||
处理第 516/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Give the approximate minimum temperature at which it is possible to austenitize a 0.20 wt% C iron-carbon alloy during a normalizing heat treatment.",
|
||
"answer": "At least 905°C (1660°F)"
|
||
},
|
||
{
|
||
"question": "Give the approximate minimum temperature at which it is possible to austenitize a 0.76 wt% C iron-carbon alloy during a normalizing heat treatment.",
|
||
"answer": "At least 782°C (1440°F)"
|
||
},
|
||
{
|
||
"question": "Give the approximate minimum temperature at which it is possible to austenitize a 0.95 wt% C iron-carbon alloy during a normalizing heat treatment.",
|
||
"answer": "At least 840°C (1545°F)"
|
||
}
|
||
]
|
||
```
|
||
处理第 517/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Give the approximate temperature at which it is desirable to heat a 0.25 wt% C iron-carbon alloy during a full anneal heat treatment.",
|
||
"answer": "About 880°C (1510°F)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which it is desirable to heat a 0.45 wt% C iron-carbon alloy during a full anneal heat treatment.",
|
||
"answer": "About 830°C (1525°F)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which it is desirable to heat a 0.85 wt% C iron-carbon alloy during a full anneal heat treatment.",
|
||
"answer": "About 777°C (1430°F)"
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which it is desirable to heat a 1.10 wt% C iron-carbon alloy during a full anneal heat treatment.",
|
||
"answer": "About 777°C (1430°F)"
|
||
}
|
||
]
|
||
```
|
||
处理第 518/832 条数据...
|
||
[
|
||
{
|
||
"question": "What is the purpose of a spheroidizing heat treatment?",
|
||
"answer": "The purpose of a spheroidizing heat treatment is to produce a very soft and ductile steel alloy having a spheroiditic microstructure."
|
||
},
|
||
{
|
||
"question": "On what classes of alloys is a spheroidizing heat treatment normally used?",
|
||
"answer": "It is normally used on medium- and high-carbon steels, which, by virtue of carbon content, are relatively hard and strong."
|
||
}
|
||
]
|
||
处理第 519/832 条数据...
|
||
It's a single issue.
|
||
处理第 520/832 条数据...
|
||
It's a single issue.
|
||
处理第 521/832 条数据...
|
||
It's a single issue.
|
||
处理第 522/832 条数据...
|
||
It's a single issue.
|
||
处理第 523/832 条数据...
|
||
[
|
||
{
|
||
"question": "The zinc blende crystal structure is one that may be generated from close-packed planes of anions. Will the stacking sequence for this structure be FCC or HCP? Why?",
|
||
"answer": "The stacking sequence of close-packed planes of anions for the zinc blende crystal structure will be the same as FCC (and not HCP) because the anion packing is FCC."
|
||
},
|
||
{
|
||
"question": "The zinc blende crystal structure is one that may be generated from close-packed planes of anions. Will cations fill tetrahedral or octahedral positions? Why?",
|
||
"answer": "The cations will fill tetrahedral positions since the coordination number for cations is four."
|
||
},
|
||
{
|
||
"question": "The zinc blende crystal structure is one that may be generated from close-packed planes of anions. What fraction of the positions will be occupied?",
|
||
"answer": "Only one-half of the tetrahedral positions will be occupied because there are two tetrahedral sites per anion, and yet only one cation per anion."
|
||
}
|
||
]
|
||
处理第 524/832 条数据...
|
||
It's a single issue.
|
||
处理第 525/832 条数据...
|
||
It's a single issue.
|
||
处理第 526/832 条数据...
|
||
It's a single issue.
|
||
处理第 527/832 条数据...
|
||
It's a single issue.
|
||
处理第 528/832 条数据...
|
||
It's a single issue.
|
||
处理第 529/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Suppose that Li2O is added as an impurity to CaO. If the Li+ substitutes for Ca2+, what kind of vacancies would you expect to form? How many of these vacancies are created for every Li+ added?",
|
||
"answer": "oxygen vacancies. Two Li+ ions added, a single oxygen vacancy is formed."
|
||
},
|
||
{
|
||
"question": "(b) Suppose that CaCl2 is added as an impurity to CaO. If the Cl substitutes for O2-, what kind of vacancies would you expect to form? How many of the vacancies are created for every Cl- added?",
|
||
"answer": "calcium vacancies. Two Cl- ions will lead to the formation of one calcium vacancy."
|
||
}
|
||
]
|
||
```
|
||
处理第 530/832 条数据...
|
||
[
|
||
{
|
||
"question": "What point defects are possible for Al2O3 as an impurity in MgO?",
|
||
"answer": "For every Al3+ ion that substitutes for Mg2+ in MgO, a single positive charge is added. Thus, in order to maintain charge neutrality, either a positive charge must be removed or a negative charge must be added. Negative charges are added by forming O2- interstitials, which are not likely to form. Positive charges may be removed by forming Mg2+ vacancies."
|
||
},
|
||
{
|
||
"question": "How many Al2+ ions must be added to form each of these defects?",
|
||
"answer": "One magnesium vacancy would be formed for every two Al3+ ions added."
|
||
}
|
||
]
|
||
处理第 531/832 条数据...
|
||
[
|
||
{
|
||
"question": "When kaolinite clay [Al2(Si2O5)(OH)4] is heated to a sufficiently high temperature, chemical water is driven off. Under these circumstances, what is the composition of the remaining product (in weight percent Al2O3)?",
|
||
"answer": "the composition of the remaining product is 45.9% Al2O3 by weight."
|
||
},
|
||
{
|
||
"question": "When kaolinite clay [Al2(Si2O5)(OH)4] is heated to a sufficiently high temperature, chemical water is driven off. What are the liquidus and solidus temperatures of this material?",
|
||
"answer": "the liquidus and solidus temperatures of this material are 1825 degrees C and 1587 degrees C, respectively."
|
||
}
|
||
]
|
||
处理第 532/832 条数据...
|
||
[
|
||
{
|
||
"question": "Why may there be significant scatter in the fracture strength for some given ceramic material?",
|
||
"answer": "There may be significant scatter in the fracture strength for some given ceramic material because the fracture strength depends on the probability of the existence of a flaw that is capable of initiating a crack; this probability varies from specimen to specimen of the same material."
|
||
},
|
||
{
|
||
"question": "Why does fracture strength increase with decreasing specimen size?",
|
||
"answer": "The fracture strength increases with decreasing specimen size because as specimen size decreases, the probability of the existence of a flaw that is capable of initiating a crack diminishes."
|
||
}
|
||
]
|
||
处理第 533/832 条数据...
|
||
It's a single issue.
|
||
处理第 534/832 条数据...
|
||
It's a single issue.
|
||
处理第 535/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A three-point transverse bending test is conducted on a cylindrical specimen of aluminum oxide having a reported flexural strength of 390 MPa (56,600 psi). If the specimen radius is 2.5 mm (0.10 in.) and the support point separation distance is 30 mm (1.2 in.), predict whether or not you would expect the specimen to fracture when a load of 620 N (140 lbf) is applied. Justify your prediction.",
|
||
"answer": "the calculated stress is 379 mpa (53,500 psi), which is less than the flexural strength of 390 mpa. therefore, fracture is not predicted."
|
||
},
|
||
{
|
||
"question": "Would you be 100% certain of the prediction in part (a)? Why or why not?",
|
||
"answer": "the certainty of this prediction is not 100% because there is always some variability in the flexural strength for ceramic materials. since the calculated stress 379 mpa is relatively close to the flexural strength 390 mpa, there is some chance that fracture will occur."
|
||
}
|
||
]
|
||
```
|
||
处理第 536/832 条数据...
|
||
It's a single issue.
|
||
处理第 537/832 条数据...
|
||
[
|
||
{
|
||
"question": "The modulus of elasticity for beryllium oxide (BeO) having 5 vol% porosity is 310 GPa (45 x 10^6 psi). Compute the modulus of elasticity for the nonporous material.",
|
||
"answer": "the modulus of elasticity for the nonporous material is 342 gpa (49.6 x 10^6 psi)."
|
||
},
|
||
{
|
||
"question": "The modulus of elasticity for beryllium oxide (BeO) having 5 vol% porosity is 310 GPa (45 x 10^6 psi). Compute the modulus of elasticity for 10 vol% porosity.",
|
||
"answer": "the modulus of elasticity for 10 vol% porosity is 280 gpa (40.6 x 10^6 psi)."
|
||
}
|
||
]
|
||
处理第 538/832 条数据...
|
||
[
|
||
{
|
||
"question": "The modulus of elasticity for boron carbide (B4C) having 5 vol% porosity is 290 GPa (42 x 10^6 psi). Compute the modulus of elasticity for the nonporous material.",
|
||
"answer": "320 GPa (46.3 x 10^6 psi)"
|
||
},
|
||
{
|
||
"question": "The modulus of elasticity for boron carbide (B4C) having 5 vol% porosity is 290 GPa (42 x 10^6 psi). At what volume percent porosity will the modulus of elasticity be 235 GPa (34 x 10^6 psi)?",
|
||
"answer": "the modulus of elasticity will be 235 GPa (34 x 10^6 psi) at a porosity of 15.1 vol%"
|
||
}
|
||
]
|
||
处理第 539/832 条数据...
|
||
It's a single issue.
|
||
处理第 540/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is crystallization?",
|
||
"answer": "Crystallization is the process whereby a glass material is caused to transform to a crystalline solid, usually as a result of a heat treatment."
|
||
},
|
||
{
|
||
"question": "Cite two properties that may be improved by crystallization.",
|
||
"answer": "Two properties that may be improved by crystallization are (1) a lower coefficient of thermal expansion, and (2) higher strength."
|
||
}
|
||
]
|
||
```
|
||
处理第 541/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For refractory ceramic materials, cite three characteristics that improve with increasing porosity.",
|
||
"answer": "For refractory ceramic materials, three characteristics that improve with increasing porosity are (1) decreased thermal expansion and contraction upon thermal cycling, (2) improved thermal insulation, and (3) improved resistance to thermal shock."
|
||
},
|
||
{
|
||
"question": "For refractory ceramic materials, cite two characteristics that are adversely affected by increasing porosity.",
|
||
"answer": "For refractory ceramic materials, two characteristics that are adversely affected by increasing porosity are (1) load-bearing capacity and (2) resistance to attack by corrosive materials."
|
||
}
|
||
]
|
||
```
|
||
处理第 542/832 条数据...
|
||
[
|
||
{
|
||
"question": "How do the aggregate particles become bonded together in clay-based mixtures during firing?",
|
||
"answer": "For clay-based aggregates, a liquid phase forms during firing, which infiltrates the pores between the unmelted particles; upon cooling, this liquid becomes a glass, that serves as the bonding phase."
|
||
},
|
||
{
|
||
"question": "How do the aggregate particles become bonded together in cements during setting?",
|
||
"answer": "With cements, the bonding process is a chemical, hydration reaction between the water that has been added and the various cement constituents. The cement particles are bonded together by reactions that occur at the particle surfaces."
|
||
}
|
||
]
|
||
处理第 543/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the glass transition temperature for a noncrystalline ceramic?",
|
||
"answer": "The glass transition temperature is, for a noncrystalline ceramic, that temperature at which there is a change of slope for the specific volume versus temperature curve."
|
||
},
|
||
{
|
||
"question": "What is the melting temperature for a crystalline material?",
|
||
"answer": "The melting temperature is, for a crystalline material and upon cooling, that temperature at which there is a sudden and discontinuous decrease in the specific-volume-versus-temperature curve."
|
||
}
|
||
]
|
||
```
|
||
处理第 544/832 条数据...
|
||
It's a single issue.
|
||
处理第 545/832 条数据...
|
||
[
|
||
{
|
||
"question": "Explain why residual thermal stresses are introduced into a glass piece when it is cooled.",
|
||
"answer": "Residual thermal stresses are introduced into a glass piece when it is cooled because surface and interior regions cool at different rates, and, therefore, contract different amounts; since the material will experience very little, if any deformation, stresses are established."
|
||
},
|
||
{
|
||
"question": "Are thermal stresses introduced upon heating? Why or why not?",
|
||
"answer": "Yes, thermal stresses will be introduced because of thermal expansion upon heating for the same reason as for thermal contraction upon cooling."
|
||
}
|
||
]
|
||
处理第 546/832 条数据...
|
||
It's a single issue.
|
||
处理第 547/832 条数据...
|
||
It's a single issue.
|
||
处理第 548/832 条数据...
|
||
It's a single issue.
|
||
处理第 549/832 条数据...
|
||
It's a single issue.
|
||
处理第 550/832 条数据...
|
||
[
|
||
{
|
||
"question": "What are the three main components of a whiteware ceramic such as porcelain?",
|
||
"answer": "clay, quartz, and a flux."
|
||
},
|
||
{
|
||
"question": "What role does each component play in the forming and firing procedures?",
|
||
"answer": "Quartz acts as a filler material. Clay facilitates the forming operation since, when mixed with water, the mass may be made to become either hydroplastic or form a slip. Also, since clays melt over a range of temperatures, the shape of the piece being fired will be maintained. The flux facilitates the formation of a glass having a relatively low melting temperature."
|
||
}
|
||
]
|
||
处理第 551/832 条数据...
|
||
[
|
||
{
|
||
"question": "Why is it so important to control the rate of drying of a ceramic body that has been hydroplastically formed or slip cast?",
|
||
"answer": "It is important to control the rate of drying inasmuch as if the rate of drying is too rapid, there will be nonuniform shrinkage between surface and interior regions, such that warping and/or cracking of the ceramic ware may result."
|
||
},
|
||
{
|
||
"question": "Cite three factors that influence the rate of drying, and explain how each affects the rate.",
|
||
"answer": "Three factors that affect the rate of drying are temperature, humidity, and rate of air flow. The rate of drying is enhanced by increasing both the temperature and rate of air flow, and by decreasing the humidity of the air."
|
||
}
|
||
]
|
||
处理第 552/832 条数据...
|
||
It's a single issue.
|
||
处理第 553/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Name three factors that influence the degree to which vitrification occurs in clay-based ceramic wares.",
|
||
"answer": "(1) composition (2) the temperature of firing(3) the time at the firing temperature."
|
||
},
|
||
{
|
||
"question": "(b) Explain how density, firing distortion, strength, corrosion resistance, and thermal conductivity are affected by the extent of vitrification.",
|
||
"answer": "Density will increase with degree of vitrification since the total remaining pore volume decreases. Firing distortion will increase with degree of vitrification since more liquid phase will be present at the firing temperature. Strength will also increase with degree of vitrification inasmuch as more of the liquid phase forms, which fills in a greater fraction of pore volume. Upon cooling, the liquid forms a glass matrix of relatively high strength. Corrosion resistance normally increases also, especially at service temperatures below that at which the glass phase begins to soften. The rate of corrosion is dependent on the amount of surface area exposed to the corrosive medium; hence, decreasing the total surface area by filling in some of the surface pores, diminishes the corrosion rate. Thermal conductivity will increase with degree of vitrification. The glass phase has a higher conductivity than the pores that it has filled."
|
||
}
|
||
]
|
||
```
|
||
处理第 554/832 条数据...
|
||
It's a single issue.
|
||
处理第 555/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compute repeat unit molecular weight for poly(vinyl chloride)",
|
||
"answer": "62.49g/mol"
|
||
},
|
||
{
|
||
"question": "Compute repeat unit molecular weight for poly(ethylene terephthalate)",
|
||
"answer": "192.16g/mol"
|
||
},
|
||
{
|
||
"question": "Compute repeat unit molecular weight for polycarbonate",
|
||
"answer": "254.27g/mol"
|
||
},
|
||
{
|
||
"question": "Compute repeat unit molecular weight for polydimethylsiloxane",
|
||
"answer": "74.16g/mol"
|
||
}
|
||
]
|
||
```
|
||
处理第 556/832 条数据...
|
||
It's a single issue.
|
||
处理第 557/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compute the repeat unit molecular weight of polystyrene.",
|
||
"answer": "the repeat unit molecular weight of polystyrene is 104.14 g/mol."
|
||
},
|
||
{
|
||
"question": "Compute the number-average molecular weight for a polystyrene for which the degree of polymerization is 25,000.",
|
||
"answer": "the number-average molecular weight for a polystyrene with a degree of polymerization of 25,000 is 2.60 x 10^6 g/mol."
|
||
}
|
||
]
|
||
处理第 558/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "High-density polyethylene may be chlorinated by inducing the random substitution of chlorine atoms for hydrogen. Determine the concentration of Cl (in wt%) that must be added if this substitution occurs for 5% of all the original hydrogen atoms.",
|
||
"answer": "the concentration of Cl that must be added is 20.3 wt%."
|
||
},
|
||
{
|
||
"question": "In what ways does this chlorinated polyethylene differ from poly(vinyl chloride)?",
|
||
"answer": "chlorinated polyethylene differs from poly(vinyl chloride) in that, for pvc, (1) 25% of the side-bonding sites are substituted with Cl, and (2) the substitution is probably much less random."
|
||
}
|
||
]
|
||
```
|
||
处理第 559/832 条数据...
|
||
[
|
||
{
|
||
"question": "Make comparisons of thermoplastic and thermosetting polymers on the basis of mechanical characteristics upon heating.",
|
||
"answer": "Thermoplastic polymers soften when heated and harden when cooled, whereas thermosetting polymers harden upon heating, while further heating will not lead to softening."
|
||
},
|
||
{
|
||
"question": "Make comparisons of thermoplastic and thermosetting polymers according to possible molecular structures.",
|
||
"answer": "Thermoplastic polymers have linear and branched structures, while for thermosetting polymers, the structures will normally be network or crosslinked."
|
||
}
|
||
]
|
||
处理第 560/832 条数据...
|
||
[
|
||
{
|
||
"question": "Is it possible to grind up and reuse phenol-formaldehyde? Why or why not?",
|
||
"answer": "It is not possible to grind up and reuse phenol-formaldehyde because it is a network thermoset polymer and, therefore, is not amenable to remolding."
|
||
},
|
||
{
|
||
"question": "Is it possible to grind up and reuse polypropylene? Why or why not?",
|
||
"answer": "Yes, it is possible to grind up and reuse polypropylene since it is a thermoplastic polymer, will soften when reheated, and, thus, may be remolded."
|
||
}
|
||
]
|
||
处理第 561/832 条数据...
|
||
It's a single issue.
|
||
处理第 562/832 条数据...
|
||
It's a single issue.
|
||
处理第 563/832 条数据...
|
||
It's a single issue.
|
||
处理第 564/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Determine the ratio of butadiene to styrene repeat units in a copolymer having a number-average molecular weight of 350,000 g/mol and degree of polymerization of 4425.",
|
||
"answer": "the ratio of butadiene to styrene repeat units is (f_{b})/(f_{s}) = (0.50)/(0.50) = 1.0."
|
||
},
|
||
{
|
||
"question": "(b) Which type(s) of copolymer(s) will this copolymer be, considering the following possibilities: random, alternating, graft, and block? Why?",
|
||
"answer": "the copolymer can be alternating, random, graft, or block. the alternating copolymer requires a 1:1 ratio, which is satisfied here, but the other types (random, graft, and block) are also possible without any ratio restrictions."
|
||
}
|
||
]
|
||
```
|
||
处理第 565/832 条数据...
|
||
It's a single issue.
|
||
处理第 566/832 条数据...
|
||
It's a single issue.
|
||
处理第 567/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (a) Linear and syndiotactic poly(vinyl chloride); linear and isotactic polystyrene.",
|
||
"answer": "Yes, for these two polymers it is possible to decide. The linear and syndiotactic poly(vinyl chloride) is more likely to crystallize; the phenyl side-group for polystyrene is bulkier than the Cl side-group for poly(vinyl chloride). Syndiotactic and isotactic isomers are equally likely to crystallize."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (b) Network phenol-formaldehyde; linear and heavily crosslinked cis-isoprene.",
|
||
"answer": "No, it is not possible to decide for these two polymers. Both heavily crosslinked and network polymers are not likely to crystallize."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (c) Linear polyethylene; lightly branched isotactic polypropylene.",
|
||
"answer": "Yes, it is possible to decide for these two polymers. The linear polyethylene is more likely to crystallize. The repeat unit structure for polypropylene is chemically more complicated than is the repeat unit structure for polyethylene. Furthermore, branched structures are less likely to crystallize than are linear structures."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (d) Alternating poly(styrene-ethylene) copolymer; random poly(vinyl chloride-tetrafluoroethylene) copolymer.",
|
||
"answer": "Yes, it is possible to decide for these two copolymers. The alternating poly(styrene-ethylene) copolymer is more likely to crystallize. Alternating copolymers crystallize more easily than do random copolymers."
|
||
}
|
||
]
|
||
```
|
||
处理第 568/832 条数据...
|
||
It's a single issue.
|
||
处理第 569/832 条数据...
|
||
It's a single issue.
|
||
处理第 570/832 条数据...
|
||
It's a single issue.
|
||
处理第 571/832 条数据...
|
||
It's a single issue.
|
||
处理第 572/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Contrast the manner in which stress relaxation and viscoelastic creep tests are conducted.",
|
||
"answer": "Stress relaxation tests are conducted by rapidly straining the material elastically in tension, holding the strain level constant, and then measuring the stress as a function of time. For viscoelastic creep tests, a stress (usually tensile) is applied instantaneously and maintained constant while strain is measured as a function of time."
|
||
},
|
||
{
|
||
"question": "(b) For each of these tests, cite the experimental parameter of interest and how it is determined.",
|
||
"answer": "The experimental parameters of interest from the stress relaxation and viscoelastic creep tests are the relaxation modulus and creep modulus (or creep compliance), respectively. The relaxation modulus is the ratio of stress measured after 10 s and strain; creep modulus is the ratio of stress and strain taken at a specific time."
|
||
}
|
||
]
|
||
处理第 573/832 条数据...
|
||
It's a single issue.
|
||
处理第 574/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the pair of polymers: random acrylonitrile-butadiene copolymer with 10% of possible sites crosslinked; alternating acrylonitrile-butadiene copolymer with 5% of possible sites crosslinked, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why.",
|
||
"answer": "No, it is not possible. The random acrylonitrile-butadiene copolymer will tend to a lower degree of crystallinity than the alternating acrylonitrile-butadiene copolymer inasmuch as random copolymers don't normally crystallize. On this basis only, the alternating material would have a higher modulus inasmuch as tensile modulus increases with degree of crystallinity. On the other hand, the random copolymer has a higher degree of crosslinking (10% versus 5% for the alternating copolymer), and, on this basis only would have the higher tensile modulus-an increase in crosslinking leads to an increase in E. Thus, this determination is not possible; with regard to degree of crystallinity the alternating material has the higher E, whereas the random copolymer would have a higher E value on the basis of degree of crosslinking."
|
||
},
|
||
{
|
||
"question": "For the pair of polymers: branched and syndiotactic polypropylene with a degree of polymerization of 5000; linear and isotactic polypropylene with a degree of polymerization of 3000, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why.",
|
||
"answer": "Yes, it is possible. The linear and isotactic polypropylene will have a greater tensile modulus. Linear polymers are more likely to crystallize that branched ones. The likelihood of crystallization for both syndiotactic and isotactic polypropylene is about the same, and, therefore, degree is crystallization is not a factor. Furthermore, tensile modulus is relatively insensitive to degree of polymerization (i.e., molecular weight)-the fact that branched PP has the higher molecular weight is not important."
|
||
},
|
||
{
|
||
"question": "For the pair of polymers: branched polyethylene with a number-average molecular weight of 250000 g/mol; linear and isotactic poly(vinyl chloride) with a number-average molecular weight of 200000 g/mol, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why.",
|
||
"answer": "No, it is not possible. Linear polymers have higher degrees of crystallization (and higher tensile moduli) than branched polymers - on this basis, the PVC material should have the higher value of E. On the other hand, PVC has a more complex repeat unit structure than does polyethylene, which means that, on this basis, the PE would have a higher degree of crystallinity and also a greater tensile modulus. Also, tensile modulus is relatively independent of number-average molecular weight. Therefore, this determination is not possible since it is not possible to determine which of the two materials has the greater degree of crystallinity."
|
||
}
|
||
]
|
||
```
|
||
处理第 575/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why. Syndiotactic polystyrene having a number-average molecular weight of 600,000 g/mol; atactic polystyrene having a number-average molecular weight of 500,000 g/mol",
|
||
"answer": "Yes it is possible. The syndiotactic polystyrene has the higher tensile strength. Syndiotactic polymers are more likely to crystallize than atactic ones; the greater the crystallinity, the higher the tensile strength. Furthermore, the syndiotactic also has a higher molecular weight; increasing molecular weight also enhances the strength."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why. Random acrylonitrile-butadiene copolymer with 10% of possible sites crosslinked; block acrylonitrile-butadiene copolymer with 5% of possible sites crosslinked",
|
||
"answer": "No it is not possible. The random acrylonitrile-butadiene copolymer has more crosslinking; increased crosslinking leads to an increase in strength. However, the block copolymeric material will most likely have a higher degree of crystallinity; and increasing crystallinity improves the strength."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and then cite the reason(s) for your choice; and (3) if it is not possible to decide, then state why. Network polyester; lightly branched polypropylene",
|
||
"answer": "Yes it is possible. The network polyester will display a greater tensile strength. Relative chain motion is much more restricted than for the lightly branched polypropylene since there are many more of the strong covalent bonds for the network structure."
|
||
}
|
||
]
|
||
```
|
||
处理第 576/832 条数据...
|
||
It's a single issue.
|
||
处理第 577/832 条数据...
|
||
It's a single issue.
|
||
处理第 578/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Isotactic polystyrene that has a density of 1.12 g/cm3 and a weight-average molecular weight of 150,000 g/mol; syndiotactic polystyrene that has a density of 1.10 g/cm3 and a weight-average molecular weight of 125,000 g/mol",
|
||
"answer": "Yes, it is possible to determine which of the two polystyrenes has the higher Tm. The isotactic polystyrene will have the higher melting temperature because it has a higher density (i.e., less branching) and also the greater weight-average molecular weight."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Linear polyethylene that has a degree of polymerization of 5,000; linear and isotactic polypropylene that has a degree of polymerization of 6,500",
|
||
"answer": "Yes, it is possible to determine which polymer has the higher melting temperature. The polypropylene will have the higher Tm because it has a bulky phenyl side group in its repeat unit structure, which is absent in the polyethylene. Furthermore, the polypropylene has a higher degree of polymerization."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether or not it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Branched and isotactic polystyrene that has a degree of polymerization of 4,000; linear and isotactic polypropylene that has a degree of polymerization of 7,500",
|
||
"answer": "No, it is not possible to determine which of the two polymers has the higher melting temperature. The polystyrene has a bulkier side group than the polypropylene; on the basis of this effect alone, the polystyrene should have the greater Tm. However, the polystyrene has more branching and a lower degree of polymerization; both of these factors lead to a lowering of the melting temperature."
|
||
}
|
||
]
|
||
```
|
||
处理第 579/832 条数据...
|
||
It's a single issue.
|
||
处理第 580/832 条数据...
|
||
It's a single issue.
|
||
处理第 581/832 条数据...
|
||
It's a single issue.
|
||
处理第 582/832 条数据...
|
||
It's a single issue.
|
||
处理第 583/832 条数据...
|
||
[
|
||
{
|
||
"question": "Estimate the maximum thermal conductivity value for a cermet that contains 85 vol % titanium carbide (TiC) particles in a cobalt matrix. Assume thermal conductivities of 27 and 69 W/m-K for TiC and Co, respectively.",
|
||
"answer": "the maximum thermal conductivity k_max is 33.3 W/m-K."
|
||
},
|
||
{
|
||
"question": "Estimate the minimum thermal conductivity value for a cermet that contains 85 vol % titanium carbide (TiC) particles in a cobalt matrix. Assume thermal conductivities of 27 and 69 W/m-K for TiC and Co, respectively.",
|
||
"answer": "the minimum thermal conductivity k_min is 29.7 W/m-K."
|
||
}
|
||
]
|
||
处理第 584/832 条数据...
|
||
It's a single issue.
|
||
处理第 585/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) What is the distinction between cement and concrete?",
|
||
"answer": "Concrete consists of an aggregate of particles that are bonded together by a cement."
|
||
},
|
||
{
|
||
"question": "(b) Cite three important limitations that restrict the use of concrete as a structural material.",
|
||
"answer": "Three limitations of concrete are: (1) it is a relatively weak and brittle material; (2) it experiences relatively large thermal expansions (contractions) with changes in temperature; and (3) it may crack when exposed to freeze-thaw cycles."
|
||
},
|
||
{
|
||
"question": "(c) Briefly explain three techniques that are utilized to strengthen concrete by reinforcement.",
|
||
"answer": "Three reinforcement strengthening techniques are: (1) reinforcement with steel wires, rods, etc.; (2) reinforcement with fine fibers of a high modulus material; and (3) introduction of residual compressive stresses by prestressing or postensioning."
|
||
}
|
||
]
|
||
处理第 586/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Cite one similarity between precipitation hardening and dispersion strengthening.",
|
||
"answer": "The similarity between precipitation hardening and dispersion strengthening is the strengthening mechanism--i.e., the precipitates/particles effectively hinder dislocation motion."
|
||
},
|
||
{
|
||
"question": "Cite two differences between precipitation hardening and dispersion strengthening.",
|
||
"answer": "The two differences are: (1) the hardening/strengthening effect is not retained at elevated temperatures for precipitation hardening--however, it is retained for dispersion strengthening; and (2) the strength is developed by a heat treatment for precipitation hardening--such is not the case for dispersion strengthening."
|
||
}
|
||
]
|
||
```
|
||
处理第 587/832 条数据...
|
||
[
|
||
{
|
||
"question": "A continuous and aligned fiber-reinforced composite is to be produced consisting of 30 vol% aramid fibers and 70 vol% of a polycarbonate matrix; mechanical characteristics of these two materials are as follows: Modulus of Elasticity for Aramid fiber is 131 GPa (19x10^6 psi) and Tensile Strength is 3600 MPa (520,000 psi); Modulus of Elasticity for Polycarbonate is 2.4 GPa (3.5x10^5 psi) and Tensile Strength is 65 MPa (9425 psi). Also, the stress on the polycarbonate matrix when the aramid fibers fail is 45 MPa (6500 psi). For this composite, compute the longitudinal tensile strength.",
|
||
"answer": "the longitudinal tensile strength is 1100 mpa (160,000 psi)."
|
||
},
|
||
{
|
||
"question": "A continuous and aligned fiber-reinforced composite is to be produced consisting of 30 vol% aramid fibers and 70 vol% of a polycarbonate matrix; mechanical characteristics of these two materials are as follows: Modulus of Elasticity for Aramid fiber is 131 GPa (19x10^6 psi) and Tensile Strength is 3600 MPa (520,000 psi); Modulus of Elasticity for Polycarbonate is 2.4 GPa (3.5x10^5 psi) and Tensile Strength is 65 MPa (9425 psi). Also, the stress on the polycarbonate matrix when the aramid fibers fail is 45 MPa (6500 psi). For this composite, compute the longitudinal modulus of elasticity.",
|
||
"answer": "the longitudinal modulus of elasticity is 41 gpa (5.95x10^6 psi)."
|
||
}
|
||
]
|
||
处理第 588/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For a continuous and oriented fiber-reinforced composite, the modulus of elasticity in the longitudinal direction is 19.7 GPa (2.8 x 10^5 psi). If the volume fraction of fibers is 0.25, determine the modulus of elasticity of the fiber phase.",
|
||
"answer": "the modulus of elasticity of the fiber phase e_f is 70.4 GPa (10.2 x 10^6 psi)."
|
||
},
|
||
{
|
||
"question": "For a continuous and oriented fiber-reinforced composite, the modulus of elasticity in the transverse direction is 3.66 GPa (5.3 x 10^5 psi). If the volume fraction of fibers is 0.25, determine the modulus of elasticity of the matrix phase.",
|
||
"answer": "the modulus of elasticity of the matrix phase e_m is 2.79 GPa (4.04 x 10^5 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 589/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "In an aligned and continuous glass fiber-reinforced nylon 6,6 composite, the fibers are to carry 94% of a load applied in the longitudinal direction. Using the data provided, determine the volume fraction of fibers that will be required.",
|
||
"answer": "the required volume fraction of fibers is 0.393."
|
||
},
|
||
{
|
||
"question": "In an aligned and continuous glass fiber-reinforced nylon 6,6 composite, the fibers are to carry 94% of a load applied in the longitudinal direction. What will be the tensile strength of this composite? Assume that the matrix stress at fiber failure is 30 MPa (4350 psi).",
|
||
"answer": "the tensile strength of this composite is 1354 mpa (196,400 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 590/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For a polymer-matrix fiber-reinforced composite, list three functions of the matrix phase.",
|
||
"answer": "For polymer-matrix fiber-reinforced composites, three functions of the polymer-matrix phase are: (1) to bind the fibers together so that the applied stress is distributed among the fibers; (2) to protect the surface of the fibers from being damaged; and (3) to separate the fibers and inhibit crack propagation."
|
||
},
|
||
{
|
||
"question": "For a polymer-matrix fiber-reinforced composite, compare the desired mechanical characteristics of matrix and fiber phases.",
|
||
"answer": "The matrix phase must be ductile and is usually relatively soft, whereas the fiber phase must be stiff and strong."
|
||
},
|
||
{
|
||
"question": "For a polymer-matrix fiber-reinforced composite, cite two reasons why there must be a strong bond between fiber and matrix at their interface.",
|
||
"answer": "There must be a strong interfacial bond between fiber and matrix in order to: (1) maximize the stress transmittance between matrix and fiber phases; and (2) minimize fiber pull-out, and the probability of failure."
|
||
}
|
||
]
|
||
```
|
||
处理第 591/832 条数据...
|
||
[
|
||
{
|
||
"question": "What is the distinction between matrix and dispersed phases in a composite material?",
|
||
"answer": "The matrix phase is a continuous phase that surrounds the noncontinuous dispersed phase."
|
||
},
|
||
{
|
||
"question": "Contrast the mechanical characteristics of matrix and dispersed phases for fiber-reinforced composites.",
|
||
"answer": "In general, the matrix phase is relatively weak, has a low elastic modulus, but is quite ductile. On the other hand, the fiber phase is normally quite strong, stiff, and brittle."
|
||
}
|
||
]
|
||
处理第 592/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly explain the difference between oxidation and reduction electrochemical reactions.",
|
||
"answer": "Oxidation is the process by which an atom gives up an electron (or electrons) to become a cation. Reduction is the process by which an atom acquires an extra electron (or electrons) and becomes an anion."
|
||
},
|
||
{
|
||
"question": "Which reaction occurs at the anode and which at the cathode?",
|
||
"answer": "Oxidation occurs at the anode; reduction at the cathode."
|
||
}
|
||
]
|
||
处理第 593/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Write the possible oxidation and reduction half-reactions that occur when magnesium is immersed in each of the following solutions: (i) HCl",
|
||
"answer": "In HCl, possible reactions are Mg -> Mg2+ + 2 e- (oxidation) and 2 H+ + 2 e- -> H2 (reduction)."
|
||
},
|
||
{
|
||
"question": "(a) Write the possible oxidation and reduction half-reactions that occur when magnesium is immersed in each of the following solutions: (ii) an HCl solution containing dissolved oxygen",
|
||
"answer": "In an HCl solution containing dissolved oxygen, possible reactions are Mg -> Mg2+ + 2 e- (oxidation) and 4 H+ + O2 + 4 e- -> 2 H2O (reduction)."
|
||
},
|
||
{
|
||
"question": "(a) Write the possible oxidation and reduction half-reactions that occur when magnesium is immersed in each of the following solutions: (iii) an HCl solution containing dissolved oxygen and, in addition, Fe2+ ions",
|
||
"answer": "In an HCl solution containing dissolved oxygen and Fe2+ ions, possible reactions are Mg -> Mg2+ + 2 e- (oxidation), 4 H+ + O2 + 4 e- -> 2 H2O (reduction), and Fe2+ + 2 e- -> Fe (reduction)."
|
||
},
|
||
{
|
||
"question": "(b) In which of these solutions would you expect the magnesium to oxidize most rapidly? Why?",
|
||
"answer": "The magnesium would probably oxidize most rapidly in the HCl solution containing dissolved oxygen and Fe2+ ions because there are two reduction reactions that will consume electrons from the oxidation of magnesium."
|
||
}
|
||
]
|
||
处理第 594/832 条数据...
|
||
[
|
||
{
|
||
"question": "Demonstrate that the value of F in Equation 17.19 is 96,500 C/mol.",
|
||
"answer": "The faraday constant F is 96,500 C/mol."
|
||
},
|
||
{
|
||
"question": "Demonstrate that at 25 C (298 K), (RT)/(nF) ln x = (0.0592)/(n) log x.",
|
||
"answer": "At 25 C (298 K), (RT)/(nF) ln x = (0.0592)/(n) log x. This gives units in volts since a volt is a J/C."
|
||
}
|
||
]
|
||
处理第 595/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Is a voltage generated between the two cell halves of a Zn/Zn2+ concentration cell where both electrodes are pure zinc, with Zn2+ concentrations of 1.0 M and 10^-2 M?",
|
||
"answer": "Yes, a voltage is generated."
|
||
},
|
||
{
|
||
"question": "What is the magnitude of the voltage generated in the Zn/Zn2+ concentration cell with Zn2+ concentrations of 1.0 M and 10^-2 M?",
|
||
"answer": "The magnitude of the voltage is 0.0592 v."
|
||
},
|
||
{
|
||
"question": "Which electrode will be oxidized in the Zn/Zn2+ concentration cell with Zn2+ concentrations of 1.0 M and 10^-2 M?",
|
||
"answer": "The electrode in the cell half with the Zn2+ concentration of 10^-2 M will be oxidized."
|
||
}
|
||
]
|
||
```
|
||
处理第 596/832 条数据...
|
||
It's a single issue.
|
||
处理第 597/832 条数据...
|
||
It's a single issue.
|
||
处理第 598/832 条数据...
|
||
[
|
||
{
|
||
"question": "Cite the major differences between activation and concentration polarizations.",
|
||
"answer": "Activation polarization is the condition wherein a reaction rate is controlled by one step in a series of steps that takes place at the slowest rate. For corrosion, activation polarization is possible for both oxidation and reduction reactions. Concentration polarization occurs when a reaction rate is limited by diffusion in a solution. For corrosion, concentration polarization is possible only for reduction reactions."
|
||
},
|
||
{
|
||
"question": "Under what conditions is activation polarization rate controlling?",
|
||
"answer": "Activation polarization is rate controlling when the reaction rate is low and/or the concentration of active species in the liquid solution is high."
|
||
},
|
||
{
|
||
"question": "Under what conditions is concentration polarization rate controlling?",
|
||
"answer": "Concentration polarization is rate controlling when the reaction rate is high and/or the concentration of active species in the liquid solution is low."
|
||
}
|
||
]
|
||
处理第 599/832 条数据...
|
||
[
|
||
{
|
||
"question": "Assuming that activation polarization controls both oxidation and reduction reactions, determine the rate of corrosion of metal M (in mol/cm2-s) given the following corrosion data: For Metal M: V(M/M2+)=-0.47 V, i0=5x10-10 A/cm2, β=+0.15; For Hydrogen: V(H+/H2)=0 V, i0=2x10-9 A/cm2, β=-0.12.",
|
||
"answer": "the rate of corrosion of metal m is 2.64x10-13 mol/cm2-s."
|
||
},
|
||
{
|
||
"question": "Compute the corrosion potential for this reaction given the following corrosion data: For Metal M: V(M/M2+)=-0.47 V, i0=5x10-10 A/cm2, β=+0.15; For Hydrogen: V(H+/H2)=0 V, i0=2x10-9 A/cm2, β=-0.12.",
|
||
"answer": "the corrosion potential for this reaction is -0.169 v."
|
||
}
|
||
]
|
||
处理第 600/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly describe the phenomenon of passivity.",
|
||
"answer": "Passivity is the loss of chemical reactivity, under particular environmental conditions, of normally active metals and alloys."
|
||
},
|
||
{
|
||
"question": "Name two common types of alloy that passivate.",
|
||
"answer": "Stainless steels and aluminum alloys often passivate."
|
||
}
|
||
]
|
||
处理第 601/832 条数据...
|
||
It's a single issue.
|
||
处理第 602/832 条数据...
|
||
It's a single issue.
|
||
处理第 603/832 条数据...
|
||
It's a single issue.
|
||
处理第 604/832 条数据...
|
||
[
|
||
{
|
||
"question": "What are inhibitors?",
|
||
"answer": "Inhibitors are substances that, when added to a corrosive environment in relatively low concentrations, decrease the environment's corrosiveness."
|
||
},
|
||
{
|
||
"question": "What possible mechanisms account for their effectiveness?",
|
||
"answer": "Possible mechanisms that account for the effectiveness of inhibitors are: (1) elimination of a chemically active species in the solution; (2) attachment of inhibitor molecules to the corroding surface so as to interfere with either the oxidation or reduction reaction; and (3) the formation of a very thin and protective coating on the corroding surface."
|
||
}
|
||
]
|
||
处理第 605/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly describe the sacrificial anode technique used for galvanic protection.",
|
||
"answer": "A sacrificial anode is electrically coupled to the metal piece to be protected, which anode is also situated in the corrosion environment. The sacrificial anode is a metal or alloy that is chemically more reactive in the particular environment. It (the anode) preferentially oxidizes, and, upon giving up electrons to the other metal, protects it from electrochemical corrosion."
|
||
},
|
||
{
|
||
"question": "Briefly describe the impressed current technique used for galvanic protection.",
|
||
"answer": "An impressed current from an external dc power source provides excess electrons to the metallic structure to be protected."
|
||
}
|
||
]
|
||
处理第 606/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compute the electrical conductivity of a 5.1-mm (0.2-in.) diameter cylindrical silicon specimen 51 mm (2 in.) long in which a current of 0.1 A passes in an axial direction. A voltage of 12.5 V is measured across two probes that are separated by 38 mm (1.5 in.).",
|
||
"answer": "the electrical conductivity is σ = 14.9 (ω·m)^-1."
|
||
},
|
||
{
|
||
"question": "Compute the resistance over the entire 51 mm (2 in.) of the specimen.",
|
||
"answer": "the resistance is r = 168 ω."
|
||
}
|
||
]
|
||
处理第 607/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Calculate the drift velocity of electrons in germanium at room temperature and when the magnitude of the electric field is 1000 V/m.",
|
||
"answer": "the drift velocity of electrons in germanium is 380 m/s."
|
||
},
|
||
{
|
||
"question": "Under these circumstances, how long does it take an electron to traverse a 25-mm (1-in.) length of crystal?",
|
||
"answer": "the time required for an electron to traverse a 25-mm length of crystal is 6.6 × 10^-5 s."
|
||
}
|
||
]
|
||
```
|
||
处理第 608/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "At room temperature the electrical conductivity and the electron mobility for copper are 6.0 x 10^7 (Ω·m)^-1 and 0.0030 m^2/V·s, respectively. Compute the number of free electrons per cubic meter for copper at room temperature.",
|
||
"answer": "the number of free electrons per cubic meter for copper at room temperature is 1.25 x 10^29 m^-3."
|
||
},
|
||
{
|
||
"question": "At room temperature the electrical conductivity and the electron mobility for copper are 6.0 x 10^7 (Ω·m)^-1 and 0.0030 m^2/V·s, respectively. What is the number of free electrons per copper atom? Assume a density of 8.9 g/cm^3.",
|
||
"answer": "the number of free electrons per copper atom is 1.48."
|
||
}
|
||
]
|
||
```
|
||
处理第 609/832 条数据...
|
||
It's a single issue.
|
||
处理第 610/832 条数据...
|
||
[
|
||
{
|
||
"question": "Define the term 'intrinsic' as it pertains to semiconducting materials and provide an example.",
|
||
"answer": "intrinsic--high purity (undoped) Si, GaAs, CdS, etc."
|
||
},
|
||
{
|
||
"question": "Define the term 'extrinsic' as it pertains to semiconducting materials and provide an example.",
|
||
"answer": "extrinsic--P-doped Ge, B-doped Si, S-doped GaP, etc."
|
||
},
|
||
{
|
||
"question": "Define the term 'compound' as it pertains to semiconducting materials and provide an example.",
|
||
"answer": "compound--GaAs, InP, CdS, etc."
|
||
},
|
||
{
|
||
"question": "Define the term 'elemental' as it pertains to semiconducting materials and provide an example.",
|
||
"answer": "elemental--Ge and Si."
|
||
}
|
||
]
|
||
处理第 611/832 条数据...
|
||
[
|
||
{
|
||
"question": "Explain why no hole is generated by the electron excitation involving a donor impurity atom.",
|
||
"answer": "No hole is generated by an electron excitation involving a donor impurity atom because the excitation comes from a level within the band gap, and thus, no missing electron is created within the normally filled valence band."
|
||
},
|
||
{
|
||
"question": "Explain why no free electron is generated by the electron excitation involving an acceptor impurity atom.",
|
||
"answer": "No free electron is generated by an electron excitation involving an acceptor impurity atom because the electron is excited from the valence band into the impurity level within the band gap; no free electron is introduced into the conduction band."
|
||
}
|
||
]
|
||
处理第 612/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Germanium to which 5 × 10^22 m^-3 Sb atoms have been added is an extrinsic semiconductor at room temperature, and virtually all the Sb atoms may be thought of as being ionized (i.e., one charge carrier exists for each Sb atom). Is this material n-type or p-type?",
|
||
"answer": "this germanium material to which has been added 5 × 10^22 m^-3 sb atoms is n-type since sb is a donor in ge."
|
||
},
|
||
{
|
||
"question": "Germanium to which 5 × 10^22 m^-3 Sb atoms have been added is an extrinsic semiconductor at room temperature, and virtually all the Sb atoms may be thought of as being ionized (i.e., one charge carrier exists for each Sb atom). Calculate the electrical conductivity of this material, assuming electron and hole mobilities of 0.1 and 0.05 m^2/V-s, respectively.",
|
||
"answer": "the electrical conductivity of this material is 800 (ω·m)^-1."
|
||
}
|
||
]
|
||
```
|
||
处理第 613/832 条数据...
|
||
It's a single issue.
|
||
处理第 614/832 条数据...
|
||
It's a single issue.
|
||
处理第 615/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is one function that a transistor may perform in an electronic circuit?",
|
||
"answer": "In an electronic circuit, a transistor may be used to amplify an electrical signal."
|
||
},
|
||
{
|
||
"question": "What is another function that a transistor may perform in an electronic circuit?",
|
||
"answer": "In an electronic circuit, a transistor may act as a switching device in computers."
|
||
}
|
||
]
|
||
```
|
||
处理第 616/832 条数据...
|
||
It's a single issue.
|
||
处理第 617/832 条数据...
|
||
It's a single issue.
|
||
处理第 618/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) For each of the three types of polarization, briefly describe the mechanism by which dipoles are induced and/or oriented by the action of an applied electric field.",
|
||
"answer": "(a) For electronic polarization, the electric field causes a net displacement of the center of the negatively charged electron cloud relative to the positive nucleus. With ionic polarization, the cations and anions are displaced in opposite directions as a result of the application of an electric field. Orientation polarization is found in substances that possess permanent dipole moments; these dipole moments become aligned in the direction of the electric field."
|
||
},
|
||
{
|
||
"question": "(b) For solid lead titanate (PbTiO3), gaseous neon, diamond, solid KCl, and liquid NH3 what kind(s) of polarization is (are) possible? Why?",
|
||
"answer": "(b) Electronic, ionic, and orientation polarizations would be observed in lead titanate. The lead, titanium, and oxygen would undoubtedly be largely ionic in character. Furthermore, orientation polarization is also possible inasmuch as permanent dipole moments may be induced in the same manner as for BaTiO3. Only electronic polarization is to be found in gaseous neon; being an inert gas, its atoms will not be ionized nor possess permanent dipole moments. Only electronic polarization is to be found in solid diamond; this material does not have molecules with permanent dipole moments, nor is it an ionic material. Both electronic and ionic polarizations will be found in solid KCl, since it is strongly ionic. In all probability, no permanent dipole moments will be found in this material. Both electronic and orientation polarizations are found in liquid NH3. The NH3 molecules have permanent dipole moments that are easily oriented in the liquid state."
|
||
}
|
||
]
|
||
```
|
||
处理第 619/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For aluminum, the heat capacity at constant volume Cv at 30 K is 0.81 J/mol-K, and the Debye temperature is 375 K. Estimate the specific heat at 50 K.",
|
||
"answer": "the specific heat at 50 K is 139 J/kg-K."
|
||
},
|
||
{
|
||
"question": "For aluminum, the heat capacity at constant volume Cv at 30 K is 0.81 J/mol-K, and the Debye temperature is 375 K. Estimate the specific heat at 425 K.",
|
||
"answer": "the specific heat at 425 K is 923 J/kg-K."
|
||
}
|
||
]
|
||
```
|
||
处理第 620/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Briefly explain why Cv rises with increasing temperature at temperatures near 0 K.",
|
||
"answer": "The reason that Cv rises with increasing temperature at temperatures near 0 K is because, in this temperature range, the allowed vibrational energy levels of the lattice waves are far apart relative to the available thermal energy, and only a portion of the lattice waves may be excited. As temperature increases, more of the lattice waves may be excited by the available thermal energy, and, hence, the ability of the solid to absorb energy (i.e., the magnitude of the heat capacity) increases."
|
||
},
|
||
{
|
||
"question": "(b) Briefly explain why Cv becomes virtually independent of temperature at temperatures far removed from 0 K.",
|
||
"answer": "At temperatures far removed from 0 K, Cv becomes independent of temperature because all of the lattice waves have been excited and the energy required to produce an incremental temperature change is nearly constant."
|
||
}
|
||
]
|
||
处理第 621/832 条数据...
|
||
It's a single issue.
|
||
处理第 622/832 条数据...
|
||
It's a single issue.
|
||
处理第 623/832 条数据...
|
||
It's a single issue.
|
||
处理第 624/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly explain why porosity decreases the thermal conductivity of ceramic and polymeric materials, rendering them more thermally insulative.",
|
||
"answer": "Porosity decreases the thermal conductivity of ceramic and polymeric materials because the thermal conductivity of a gas phase that occupies pore space is extremely small relative to that of the solid material. Furthermore, contributions from gaseous convection are generally insignificant."
|
||
},
|
||
{
|
||
"question": "Briefly explain how the degree of crystallinity affects the thermal conductivity of polymeric materials and why.",
|
||
"answer": "Increasing the degree of crystallinity of a semicrystalline polymer enhances its thermal conductivity; the vibrations, rotations, etc. of the molecular chains are more effective modes of thermal transport when a crystalline structure prevails."
|
||
}
|
||
]
|
||
处理第 625/832 条数据...
|
||
It's a single issue.
|
||
处理第 626/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Pure copper; aluminum bronze (95 wt% Cu-5 wt% Al).",
|
||
"answer": "Pure copper will have a larger conductivity than aluminum bronze because the impurity atoms in the latter will lead to a greater degree of free electron scattering."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Fused silica; quartz.",
|
||
"answer": "Quartz will have a larger conductivity than fused silica because fused silica is noncrystalline (whereas quartz is crystalline) and lattice vibrations are more effectively scattered in noncrystalline materials."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Linear polyethylene; branched polyethylene.",
|
||
"answer": "The linear polyethylene will have the larger conductivity than the branched polyethylene because the former will have the higher degree of crystallinity. Linear polymers have higher degrees of crystallinity than branched polymers. Since heat transfer is accomplished by molecular chain vibrations, and the coordination of these vibrations increases with percent crystallinity, the higher the crystallinity, the greater the thermal conductivity."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Random poly(styrene-butadiene) copolymer; alternating poly(styrene-butadiene) copolymer.",
|
||
"answer": "The alternating poly(styrene-butadiene) copolymer will have a higher crystallinity than the random copolymer; alternating copolymers crystallize more easily than random ones. The influence of crystallinity on conductivity is explained in part (c)."
|
||
}
|
||
]
|
||
```
|
||
处理第 627/832 条数据...
|
||
[
|
||
{
|
||
"question": "Explain the two sources of magnetic moments for electrons.",
|
||
"answer": "The two sources of magnetic moments for electrons are the electron's orbital motion around the nucleus, and also, its spin."
|
||
},
|
||
{
|
||
"question": "Do all electrons have a net magnetic moment? Why or why not?",
|
||
"answer": "Each electron will have a net magnetic moment from spin, and possibly, orbital contributions, which do not cancel for an isolated atom."
|
||
},
|
||
{
|
||
"question": "Do all atoms have a net magnetic moment? Why or why not?",
|
||
"answer": "All atoms do not have a net magnetic moment. If an atom has completely filled electron shells or subshells, there will be a cancellation of both orbital and spin magnetic moments."
|
||
}
|
||
]
|
||
处理第 628/832 条数据...
|
||
It's a single issue.
|
||
处理第 629/832 条数据...
|
||
It's a single issue.
|
||
处理第 630/832 条数据...
|
||
It's a single issue.
|
||
处理第 631/832 条数据...
|
||
[
|
||
{
|
||
"question": "Why does the magnitude of the saturation magnetization decrease with increasing temperature for ferromagnetic materials?",
|
||
"answer": "The saturation magnetization decreases with increasing temperature because the atomic thermal vibrational motions counteract the coupling forces between the adjacent atomic dipole moments, causing some magnetic dipole misalignment."
|
||
},
|
||
{
|
||
"question": "Why does ferromagnetic behavior cease above the Curie temperature for ferromagnetic materials?",
|
||
"answer": "Ferromagnetic behavior ceases above the Curie temperature because the atomic thermal vibrations are sufficiently violent so as to completely destroy the mutual spin coupling forces."
|
||
}
|
||
]
|
||
处理第 632/832 条数据...
|
||
It's a single issue.
|
||
处理第 633/832 条数据...
|
||
[
|
||
{
|
||
"question": "Visible light having a wavelength of 6 x 10^-7 m appears orange. Compute the frequency of a photon of this light.",
|
||
"answer": "the frequency of the photon is 5 x 10^14 s^-1."
|
||
},
|
||
{
|
||
"question": "Visible light having a wavelength of 6 x 10^-7 m appears orange. Compute the energy of a photon of this light.",
|
||
"answer": "the energy of the photon is 3.31 x 10^-19 j (2.07 ev)."
|
||
}
|
||
]
|
||
处理第 634/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What are the characteristics of opaque materials in terms of their appearance and light transmittance?",
|
||
"answer": "Opaque materials are impervious to light transmission; it is not possible to see through them."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of translucent materials in terms of their appearance and light transmittance?",
|
||
"answer": "Light is transmitted diffusely through translucent materials (there is some internal light scattering). Objects are not clearly distinguishable when viewed through a translucent material."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of transparent materials in terms of their appearance and light transmittance?",
|
||
"answer": "Virtually all of the incident light is transmitted through transparent materials, and one can see clearly through them."
|
||
}
|
||
]
|
||
```
|
||
处理第 635/832 条数据...
|
||
It's a single issue.
|
||
处理第 636/832 条数据...
|
||
It's a single issue.
|
||
处理第 637/832 条数据...
|
||
It's a single issue.
|
||
处理第 638/832 条数据...
|
||
It's a single issue.
|
||
处理第 639/832 条数据...
|
||
It's a single issue.
|
||
处理第 640/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly explain what determines the characteristic color of a metal.",
|
||
"answer": "The characteristic color of a metal is determined by the distribution of wavelengths of the nonabsorbed light radiation that is reflected."
|
||
},
|
||
{
|
||
"question": "Briefly explain what determines the characteristic color of a transparent nonmetal.",
|
||
"answer": "The characteristic color of a transparent nonmetal is determined by the distribution of wavelengths of the nonabsorbed light radiation that is transmitted through the material."
|
||
}
|
||
]
|
||
处理第 641/832 条数据...
|
||
It's a single issue.
|
||
处理第 642/832 条数据...
|
||
It's a single issue.
|
||
处理第 643/832 条数据...
|
||
It's a single issue.
|
||
处理第 644/832 条数据...
|
||
It's a single issue.
|
||
处理第 645/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Potassium iodide (KI) exhibits predominantly ionic bonding. The K+ ion has an electron structure that is identical to which inert gas?",
|
||
"answer": "The K+ ion is just a potassium atom that has lost one electron; therefore, it has an electron configuration the same as argon."
|
||
},
|
||
{
|
||
"question": "Potassium iodide (KI) exhibits predominantly ionic bonding. The I- ion has an electron structure that is identical to which inert gas?",
|
||
"answer": "The I- ion is an iodine atom that has acquired one extra electron; therefore, it has an electron configuration the same as xenon."
|
||
}
|
||
]
|
||
```
|
||
处理第 646/832 条数据...
|
||
It's a single issue.
|
||
处理第 647/832 条数据...
|
||
It's a single issue.
|
||
处理第 648/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{5}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{5}\) electron configuration is that of a halogen because it is one electron deficient from having a filled \(p\) subshell."
|
||
},
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{7} 4 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{7} 4 s^{2}\) electron configuration is that of a transition metal because of an incomplete \(d\) subshell."
|
||
},
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6}\) electron configuration is that of an inert gas because of filled \(4 s\) and \(4 p\) subshells."
|
||
},
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 4 s^{1}\) electron configuration is that of an alkali metal because of a single \(s\) electron."
|
||
},
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{5} 5 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2} 3 p^{6} 3 d^{10} 4 s^{2} 4 p^{6} 4 d^{5} 5 s^{2}\) electron configuration is that of a transition metal because of an incomplete \(d\) subshell."
|
||
},
|
||
{
|
||
"question": "Without consulting Figure or Table, determine whether the electron configuration \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\) is an inert gas, a halogen, an alkali metal, an alkaline earth metal, or a transition metal. Justify your choice.",
|
||
"answer": "The \(1 s^{2} 2 s^{2} 2 p^{6} 3 s^{2}\) electron configuration is that of an alkaline earth metal because of two \(s\) electrons."
|
||
}
|
||
]
|
||
```
|
||
API调用错误: Invalid \escape: line 3 column 103 (char 110)
|
||
处理第 649/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Differentiate \(E_{N}\) with respect to \(r\), and then set the resulting expression equal to zero, because the curve of \(E_{N}\) versus \(r\) is a minimum at \(E_{0}\).",
|
||
"answer": "The derivative of \(E_{N}\) with respect to \(r\) is set to zero to find the minimum."
|
||
},
|
||
{
|
||
"question": "Solve for \(r\) in terms of \(A, B\), and \(n\), which yields \(r_{0}\), the equilibrium interionic spacing.",
|
||
"answer": "The equilibrium interionic spacing \(r_{0}\) is solved in terms of \(A, B\), and \(n\)."
|
||
},
|
||
{
|
||
"question": "Determine the expression for \(E_{0}\) by substitution of \(r_{0}\) into Equation.",
|
||
"answer": "The bonding energy \(e_{0}\) is given by: \(e_{0}=-\frac{a}{\left(\frac{a}{nb}\right)^{1 /(1-n)}}+\frac{b}{\left(\frac{a}{nb}\right)^{n /(1-n)}}\)"
|
||
}
|
||
]
|
||
```
|
||
API调用错误: Invalid \escape: line 3 column 36 (char 43)
|
||
处理第 650/832 条数据...
|
||
It's a single issue.
|
||
处理第 651/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What type(s) of bonding would be expected for solid xenon?",
|
||
"answer": "For solid xenon, the bonding is van der Waals since xenon is an inert gas."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for calcium fluoride (CaF2)?",
|
||
"answer": "For CaF2, the bonding is predominantly ionic (but with some slight covalent character) on the basis of the relative positions of Ca and F in the periodic table."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for bronze?",
|
||
"answer": "For bronze, the bonding is metallic since it is a metal alloy (composed of copper and tin)."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for cadmium telluride (CdTe)?",
|
||
"answer": "For CdTe, the bonding is predominantly covalent (with some slight ionic character) on the basis of the relative positions of Cd and Te in the periodic table."
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for rubber?",
|
||
"answer": "For rubber, the bonding is covalent with some van der Waals. (Rubber is composed primarily of carbon and hydrogen atoms.)"
|
||
},
|
||
{
|
||
"question": "What type(s) of bonding would be expected for tungsten?",
|
||
"answer": "For tungsten, the bonding is metallic since it is a metallic element from the periodic table."
|
||
}
|
||
]
|
||
```
|
||
处理第 652/832 条数据...
|
||
It's a single issue.
|
||
处理第 653/832 条数据...
|
||
It's a single issue.
|
||
处理第 654/832 条数据...
|
||
It's a single issue.
|
||
处理第 655/832 条数据...
|
||
It's a single issue.
|
||
处理第 656/832 条数据...
|
||
It's a single issue.
|
||
处理第 657/832 条数据...
|
||
It's a single issue.
|
||
处理第 658/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Titanium (Ti) has an HCP crystal structure and a density of 4.51 g/cm^3. What is the volume of its unit cell in cubic meters?",
|
||
"answer": "the volume of the ti unit cell is 1.058 x 10^-28 m^3."
|
||
},
|
||
{
|
||
"question": "Titanium (Ti) has an HCP crystal structure and a density of 4.51 g/cm^3. If the c/a ratio is 1.58, compute the values of c and a.",
|
||
"answer": "the values of a and c are 0.296 nm and 0.468 nm, respectively."
|
||
}
|
||
]
|
||
```
|
||
处理第 659/832 条数据...
|
||
[
|
||
{
|
||
"question": "Magnesium (Mg) has an HCP crystal structure and a density of 1.74 g/cm3. What is the volume of its unit cell in cubic centimeters?",
|
||
"answer": "the volume of the unit cell is 1.39 × 10^-22 cm3."
|
||
},
|
||
{
|
||
"question": "Magnesium (Mg) has an HCP crystal structure and a density of 1.74 g/cm3. If the c/a ratio is 1.624, compute the values of c and a.",
|
||
"answer": "the values of a and c are 0.321 nm and 0.521 nm, respectively."
|
||
}
|
||
]
|
||
处理第 660/832 条数据...
|
||
It's a single issue.
|
||
处理第 661/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Indium (In) has a tetragonal unit cell for which the a and c lattice parameters are 0.459 and 0.495 nm, respectively. If the atomic packing factor and atomic radius are 0.693 and 0.1625 nm, respectively, determine the number of atoms in each unit cell.",
|
||
"answer": "4.0 atoms/unit cell"
|
||
},
|
||
{
|
||
"question": "Indium (In) has a tetragonal unit cell for which the a and c lattice parameters are 0.459 and 0.495 nm, respectively. The atomic weight of indium is 114.82 g/mol; compute its theoretical density.",
|
||
"answer": "7.31 g/cm3"
|
||
}
|
||
]
|
||
```
|
||
处理第 662/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Beryllium (Be) has an HCP unit cell for which the ratio of the lattice parameters \(c / a\) is 1.568. If the radius of the Be atom is \(0.1143 \mathrm{~nm}\), determine the unit cell volume.",
|
||
"answer": "the unit cell volume for be is \(4.87 \times 10^{-23} \mathrm{~cm}^{3}\)."
|
||
},
|
||
{
|
||
"question": "Beryllium (Be) has an HCP unit cell for which the ratio of the lattice parameters \(c / a\) is 1.568. If the radius of the Be atom is \(0.1143 \mathrm{~nm}\), calculate the theoretical density of Be and compare it with the literature value.",
|
||
"answer": "the theoretical density of be is \(1.84 \mathrm{~g/cm}^3\), and the literature value is \(1.85 \mathrm{~g/cm}^{3}\)."
|
||
}
|
||
]
|
||
```
|
||
API调用错误: Invalid \escape: line 3 column 104 (char 111)
|
||
处理第 663/832 条数据...
|
||
It's a single issue.
|
||
处理第 664/832 条数据...
|
||
It's a single issue.
|
||
处理第 665/832 条数据...
|
||
It's a single issue.
|
||
处理第 666/832 条数据...
|
||
It's a single issue.
|
||
处理第 667/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Iron titanate, FeTiO3, forms in the ilmenite crystal structure that consists of an HCP arrangement of O2- ions. Which type of interstitial site will the Fe2+ ions occupy? Why?",
|
||
"answer": "From Table, the cation-anion radius ratio is 0.077 nm / 0.140 nm = 0.550. Since this ratio is between 0.414 and 0.732, the Fe2+ ions will occupy octahedral sites."
|
||
},
|
||
{
|
||
"question": "Iron titanate, FeTiO3, forms in the ilmenite crystal structure that consists of an HCP arrangement of O2- ions. Which type of interstitial site will the Ti4+ ions occupy? Why?",
|
||
"answer": "The titanium-oxygen ionic radius ratio is 0.0601 nm / 0.140 nm = 0.436. Since this ratio is between 0.414 and 0.723, the Ti4+ ions will also occupy octahedral sites."
|
||
},
|
||
{
|
||
"question": "Iron titanate, FeTiO3, forms in the ilmenite crystal structure that consists of an HCP arrangement of O2- ions. What fraction of the total tetrahedral sites will be occupied?",
|
||
"answer": "Since both Fe2+ and Ti4+ ions occupy octahedral sites, no tetrahedral sites will be occupied."
|
||
},
|
||
{
|
||
"question": "Iron titanate, FeTiO3, forms in the ilmenite crystal structure that consists of an HCP arrangement of O2- ions. What fraction of the total octahedral sites will be occupied?",
|
||
"answer": "For every FeTiO3 formula unit, there are three O2- ions, and, therefore, three octahedral sites; since there is one ion each of Fe2+ and Ti4+ per formula unit, two-thirds of these octahedral sites will be occupied."
|
||
}
|
||
]
|
||
```
|
||
处理第 668/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "To what equation does the expression for interplanar spacing \(d_{\text {hkl }}\) reduce for crystals having cubic symmetry, given that \(a, b\), and \(c\) are the lattice parameters?",
|
||
"answer": "For the crystals having cubic symmetry, \(a=b=c\). Making this substitution into the given equation leads to \(\frac{1}{d_{h k l}^{2}}=\frac{h^{2}}{a^{2}}+\frac{k^{2}}{a^{2}}+\frac{l^{2}}{a^{2}} = \frac{h^{2}+k^{2}+l^{2}}{a^{2}}\)."
|
||
},
|
||
{
|
||
"question": "To what equation does the expression for interplanar spacing \(d_{\text {hkl }}\) reduce for crystals having tetragonal symmetry, given that \(a, b\), and \(c\) are the lattice parameters?",
|
||
"answer": "For crystals having tetragonal symmetry, \(a=b \neq c\). Replacing \(b\) with \(a\) in the given equation leads to \(\frac{1}{d_{h k l}^{2}}=\frac{h^{2}}{a^{2}}+\frac{k^{2}}{a^{2}}+\frac{l^{2}}{c^{2}} = \frac{h^{2}+k^{2}}{a^{2}}+\frac{l^{2}}{c^{2}}\)."
|
||
}
|
||
]
|
||
```
|
||
API调用错误: Invalid \escape: line 3 column 83 (char 90)
|
||
处理第 669/832 条数据...
|
||
It's a single issue.
|
||
处理第 670/832 条数据...
|
||
[
|
||
{
|
||
"question": "High-density polyethylene may be chlorinated by inducing the random substitution of chlorine atoms for hydrogen. Determine the concentration of Cl (in wt%) that must be added if this substitution occurs for 8% of all the original hydrogen atoms.",
|
||
"answer": "the concentration of Cl that must be added is 29.0 wt%."
|
||
},
|
||
{
|
||
"question": "High-density polyethylene may be chlorinated by inducing the random substitution of chlorine atoms for hydrogen. In what ways does this chlorinated polyethylene differ from poly(vinyl chloride)?",
|
||
"answer": "chlorinated polyethylene differs from poly(vinyl chloride) in that, for pvc, (1) 25% of the side-bonding sites are substituted with Cl, and (2) the substitution is probably much less random."
|
||
}
|
||
]
|
||
处理第 671/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compare thermoplastic and thermosetting polymers on the basis of mechanical characteristics upon heating.",
|
||
"answer": "Thermoplastic polymers soften when heated and harden when cooled, whereas thermosetting polymers harden upon heating, while further heating will not lead to softening."
|
||
},
|
||
{
|
||
"question": "Compare thermoplastic and thermosetting polymers according to possible molecular structures.",
|
||
"answer": "Thermoplastic polymers have linear and branched structures, while for thermosetting polymers, the structures will normally be network or crosslinked."
|
||
}
|
||
]
|
||
处理第 672/832 条数据...
|
||
It's a single issue.
|
||
处理第 673/832 条数据...
|
||
It's a single issue.
|
||
处理第 674/832 条数据...
|
||
It's a single issue.
|
||
处理第 675/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Determine the ratio of butadiene to acrylonitrile repeat units in a copolymer having a number-average molecular weight of 250,000 g/mol and a degree of polymerization of 4640.",
|
||
"answer": "the ratio of butadiene to acrylonitrile repeat units in the copolymer is fb/fa = 4.0."
|
||
},
|
||
{
|
||
"question": "(b) Which type(s) of copolymer(s) will this copolymer be, considering the following possibilities: random, alternating, graft, and block? Why?",
|
||
"answer": "of the possible copolymers, the only one for which there is a restriction on the ratio of repeat unit types is alternating; the ratio must be 1:1. therefore, on the basis of the result in part (a), the possibilities for this copolymer are random, graft, and block."
|
||
}
|
||
]
|
||
处理第 676/832 条数据...
|
||
It's a single issue.
|
||
处理第 677/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) State whether it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (a) Linear and atactic poly(vinyl chloride); linear and isotactic polypropylene",
|
||
"answer": "No, it is not possible to decide for these two polymers. On the basis of tacticity, the isotactic PP is more likely to crystallize than the atactic PVC. On the other hand, with regard to side-group bulkiness, the PVC is more likely to crystallize."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) State whether it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (b) Linear and syndiotactic polypropylene; crosslinked cis-polyisoprene",
|
||
"answer": "Yes, it is possible to decide for these two copolymers. The linear and syndiotactic polypropylene is more likely to crystallize than crosslinked cis-isoprene because linear polymers are more likely to crystallize than crosslinked ones."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) State whether it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (c) Network phenol-formaldehyde; linear and isotactic polystyrene",
|
||
"answer": "Yes, it is possible to decide for these two polymers. The linear and isotactic polystyrene is more likely to crystallize than network phenol-formaldehyde; network polymers rarely crystallize, whereas isotactic ones crystallize relatively easily."
|
||
},
|
||
{
|
||
"question": "For the following pairs of polymers, do the following: (1) State whether it is possible to determine whether one polymer is more likely to crystallize than the other; (2) if it is possible, note which is the more likely and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. (d) Block poly(acrylonitrile-isoprene) copolymer; graft poly(chloroprene-isobutylene) copolymer",
|
||
"answer": "Yes, it is possible to decide for these two copolymers. The block poly(acrylonitrileisoprene) copolymer is more likely to crystallize than the graft poly(chloroprene-isobutylene) copolymer. Block copolymers crystallize more easily than graft ones."
|
||
}
|
||
]
|
||
```
|
||
处理第 678/832 条数据...
|
||
It's a single issue.
|
||
处理第 679/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Calculate the fraction of atom sites that are vacant for copper (Cu) at its melting temperature of 1084°C (1357 K). Assume an energy for vacancy formation of 0.90 eV/atom.",
|
||
"answer": "the fraction of atom sites that are vacant for copper at 1357 k is 4.56 × 10^-4."
|
||
},
|
||
{
|
||
"question": "(b) Repeat this calculation at room temperature (298 K). Assume an energy for vacancy formation of 0.90 eV/atom.",
|
||
"answer": "the fraction of atom sites that are vacant for copper at 298 k is 6.08 × 10^-16."
|
||
},
|
||
{
|
||
"question": "(c) What is ratio of N_V/N(1357 K) and N_V/N(298 K) ?",
|
||
"answer": "the ratio of n_v/n(1357 k) to n_v/n(298 k) is 7.5 × 10^11."
|
||
}
|
||
]
|
||
```
|
||
处理第 680/832 条数据...
|
||
It's a single issue.
|
||
处理第 681/832 条数据...
|
||
It's a single issue.
|
||
处理第 682/832 条数据...
|
||
It's a single issue.
|
||
处理第 683/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Under conditions where cupric oxide (CuO) is exposed to reducing atmospheres at elevated temperatures, some of the Cu2+ ions will become Cu+. Name one crystalline defect that you would expect to form in order to maintain charge neutrality.",
|
||
"answer": "For a Cu2+ O2- compound in which a small fraction of the copper ions exist as Cu+, for each Cu+ formed there is one less positive charge introduced (or one more negative charge). In order to maintain charge neutrality, we must either add an additional positive charge or subtract a negative charge. This may be accomplished be either creating Cu2+ interstitials or O2- vacancies."
|
||
},
|
||
{
|
||
"question": "Under conditions where cupric oxide (CuO) is exposed to reducing atmospheres at elevated temperatures, some of the Cu2+ ions will become Cu+. How many Cu+ ions are required for the creation of each defect?",
|
||
"answer": "There will be two Cu+ ions required for each of these defects."
|
||
},
|
||
{
|
||
"question": "Under conditions where cupric oxide (CuO) is exposed to reducing atmospheres at elevated temperatures, some of the Cu2+ ions will become Cu+. How would you express the chemical formula for this nonstoichiometric material?",
|
||
"answer": "The chemical formula for this nonstoichiometric material is Cu1+ O or CuO1-x, where x is some small fraction."
|
||
}
|
||
]
|
||
```
|
||
处理第 684/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MgO? Explain your answer for FeO.",
|
||
"answer": "For FeO, the ionic radii of the Mg2+ and Fe2+ are 0.072 nm and 0.077 nm, respectively. The percentage difference in ionic radii is 6.5%, which is within the acceptable range for a high degree of solubility. Additionally, both MgO and FeO have rock salt crystal structures. Therefore, FeO and MgO are expected to form high degrees of solid solubility, and experimentally, they exhibit 100% solubility."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MgO? Explain your answer for BaO.",
|
||
"answer": "For BaO, the ionic radii of the Mg2+ and Ba2+ are 0.072 nm and 0.136 nm, respectively. The percentage difference in ionic radii is 47%, which is much larger than the acceptable range. Therefore, BaO is not expected to experience any appreciable solubility in MgO. Experimentally, the solubility of BaO in MgO is very small."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MgO? Explain your answer for PbO.",
|
||
"answer": "For PbO, the ionic radii of the Mg2+ and Pb2+ are 0.072 nm and 0.120 nm, respectively. The percentage difference in ionic radii is 40%, which is much larger than the acceptable range. Therefore, PbO is not expected to experience any appreciable solubility in MgO."
|
||
},
|
||
{
|
||
"question": "Which of the following oxides would you expect to form substitutional solid solutions that have complete (i.e., 100%) solubility with MgO? Explain your answer for CoO.",
|
||
"answer": "For CoO, the ionic radii of the Mg2+ and Co2+ are 0.072 nm and 0.072 nm, respectively. The percentage difference in ionic radii is 0%, which is within the acceptable range for a high degree of solubility. Therefore, CoO and MgO are expected to form high degrees of solid solubility, likely 100%."
|
||
}
|
||
]
|
||
```
|
||
处理第 685/832 条数据...
|
||
[
|
||
{
|
||
"question": "Suppose that CaO is added as an impurity to Li2O. If the Ca2+ substitutes for Li+, what kind of vacancies would you expect to form? How many of these vacancies are created for every Ca2+ added?",
|
||
"answer": "For Ca2+ substituting for Li+ in Li2O, lithium vacancies would be created. For each Ca2+ substituting for Li+, one positive charge is added; in order to maintain charge neutrality, a single positive charge may be removed. Positive charges are eliminated by creating lithium vacancies, and for every Ca2+ ion added, a single lithium vacancy is formed."
|
||
},
|
||
{
|
||
"question": "Suppose that CaO is added as an impurity to CaCl2. If the O2- substitutes for Cl-, what kind of vacancies would you expect to form? How many of these vacancies are created for every O2- added?",
|
||
"answer": "For O2- substituting for Cl- in CaCl2, chlorine vacancies would be created. For each O2- substituting for a Cl-, one negative charge is added; negative charges are eliminated by creating chlorine vacancies. In order to maintain charge neutrality, one O2- ion will lead to the formation of one chlorine vacancy."
|
||
}
|
||
]
|
||
处理第 686/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Which of these elements would you expect to form a substitutional solid solution having complete solubility with nickel? The four Hume-Rothery rules must be satisfied: (1) the difference in atomic radii between Ni and the other element (ΔR%) must be less than ±15%; (2) the crystal structures must be the same; (3) the electronegativities must be similar; and (4) the valences should be the same.",
|
||
"answer": "Pt is the only element that meets all of the criteria and thus forms a substitutional solid solution having complete solubility. At elevated temperatures Co and Fe experience allotropic transformations to the FCC crystal structure, and thus display complete solid solubility at these temperatures."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form a substitutional solid solution of incomplete solubility with nickel? The four Hume-Rothery rules must be satisfied: (1) the difference in atomic radii between Ni and the other element (ΔR%) must be less than ±15%; (2) the crystal structures must be the same; (3) the electronegativities must be similar; and (4) the valences should be the same.",
|
||
"answer": "Ag, Al, Co, Cr, Fe, and Zn form substitutional solid solutions of incomplete solubility. All these metals have either BCC or HCP crystal structures, and/or the difference between their atomic radii and that for Ni are greater than ±15%, and/or have a valence different than 2+."
|
||
},
|
||
{
|
||
"question": "Which of these elements would you expect to form an interstitial solid solution with nickel? The four Hume-Rothery rules must be satisfied: (1) the difference in atomic radii between Ni and the other element (ΔR%) must be less than ±15%; (2) the crystal structures must be the same; (3) the electronegativities must be similar; and (4) the valences should be the same.",
|
||
"answer": "C, H, and O form interstitial solid solutions. These elements have atomic radii that are significantly smaller than the atomic radius of Ni."
|
||
}
|
||
]
|
||
```
|
||
处理第 687/832 条数据...
|
||
It's a single issue.
|
||
处理第 688/832 条数据...
|
||
It's a single issue.
|
||
处理第 689/832 条数据...
|
||
It's a single issue.
|
||
处理第 690/832 条数据...
|
||
It's a single issue.
|
||
处理第 691/832 条数据...
|
||
It's a single issue.
|
||
处理第 692/832 条数据...
|
||
It's a single issue.
|
||
处理第 693/832 条数据...
|
||
It's a single issue.
|
||
处理第 694/832 条数据...
|
||
It's a single issue.
|
||
处理第 695/832 条数据...
|
||
It's a single issue.
|
||
处理第 696/832 条数据...
|
||
It's a single issue.
|
||
处理第 697/832 条数据...
|
||
It's a single issue.
|
||
处理第 698/832 条数据...
|
||
It's a single issue.
|
||
处理第 699/832 条数据...
|
||
It's a single issue.
|
||
处理第 700/832 条数据...
|
||
It's a single issue.
|
||
处理第 701/832 条数据...
|
||
It's a single issue.
|
||
处理第 702/832 条数据...
|
||
It's a single issue.
|
||
处理第 703/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For an ASTM grain size of 6, approximately how many grains would there be per square inch at a magnification of 100x?",
|
||
"answer": "32 grains/in.^2"
|
||
},
|
||
{
|
||
"question": "For an ASTM grain size of 6, approximately how many grains would there be per square inch without any magnification?",
|
||
"answer": "320000 grains/in.^2"
|
||
}
|
||
]
|
||
```
|
||
处理第 704/832 条数据...
|
||
It's a single issue.
|
||
处理第 705/832 条数据...
|
||
It's a single issue.
|
||
处理第 706/832 条数据...
|
||
It's a single issue.
|
||
处理第 707/832 条数据...
|
||
It's a single issue.
|
||
处理第 708/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compare interstitial and vacancy atomic mechanisms for diffusion.",
|
||
"answer": "With vacancy diffusion, atomic motion is from one lattice site to an adjacent vacancy. Self-diffusion and the diffusion of substitutional impurities proceed via this mechanism. On the other hand, atomic motion is from interstitial site to adjacent interstitial site for the interstitial diffusion mechanism."
|
||
},
|
||
{
|
||
"question": "Cite two reasons why interstitial diffusion is normally more rapid than vacancy diffusion.",
|
||
"answer": "Interstitial diffusion is normally more rapid than vacancy diffusion because: (1) interstitial atoms, being smaller, are more mobile; and (2) the probability of an empty adjacent interstitial site is greater than for a vacancy adjacent to a host (or substitutional impurity) atom."
|
||
}
|
||
]
|
||
处理第 709/832 条数据...
|
||
It's a single issue.
|
||
处理第 710/832 条数据...
|
||
It's a single issue.
|
||
处理第 711/832 条数据...
|
||
It's a single issue.
|
||
处理第 712/832 条数据...
|
||
It's a single issue.
|
||
处理第 713/832 条数据...
|
||
It's a single issue.
|
||
处理第 714/832 条数据...
|
||
It's a single issue.
|
||
处理第 715/832 条数据...
|
||
It's a single issue.
|
||
处理第 716/832 条数据...
|
||
It's a single issue.
|
||
处理第 717/832 条数据...
|
||
It's a single issue.
|
||
处理第 718/832 条数据...
|
||
It's a single issue.
|
||
处理第 719/832 条数据...
|
||
It's a single issue.
|
||
处理第 720/832 条数据...
|
||
[
|
||
{
|
||
"question": "For a brass alloy, the stress at which plastic deformation begins is 345 MPa (50,000 psi), and the modulus of elasticity is 103 GPa (15.0 x 10^6 psi). What is the maximum load that can be applied to a specimen with a cross-sectional area of 130 mm^2 (0.2 in.^2) without plastic deformation?",
|
||
"answer": "the maximum load that can be applied without plastic deformation is 44,850 n (10,000 lb_f)."
|
||
},
|
||
{
|
||
"question": "For a brass alloy, the stress at which plastic deformation begins is 345 MPa (50,000 psi), and the modulus of elasticity is 103 GPa (15.0 x 10^6 psi). If the original specimen length is 76 mm (3.0 in.), what is the maximum length to which it can be stretched without causing plastic deformation?",
|
||
"answer": "the maximum length to which the specimen can be stretched without causing plastic deformation is 76.25 mm (3.01 in.)."
|
||
}
|
||
]
|
||
处理第 721/832 条数据...
|
||
It's a single issue.
|
||
处理第 722/832 条数据...
|
||
It's a single issue.
|
||
处理第 723/832 条数据...
|
||
It's a single issue.
|
||
处理第 724/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A cylindrical rod 500 mm (20.0 in.) long and having a diameter of 12.7 mm (0.50 in.) is to be subjected to a tensile load of 29,000 N (6500 lb). Which of the four metals or alloys listed in the table can experience neither plastic deformation nor an elongation of more than 1.3 mm (0.05 in.)?",
|
||
"answer": "Of the four metal alloys listed, only brass and steel satisfy the stipulated criteria. Brass has an elongation of 1.15 mm, and steel has an elongation of 0.56 mm, both of which are less than the maximum allowed elongation of 1.3 mm."
|
||
},
|
||
{
|
||
"question": "Why is aluminum alloy not a candidate for the cylindrical rod subjected to a tensile load of 29,000 N (6500 lb) with a maximum allowed elongation of 1.3 mm (0.05 in.)?",
|
||
"answer": "Aluminum alloy is not a candidate because its elongation of 1.64 mm exceeds the limit."
|
||
},
|
||
{
|
||
"question": "Why is copper not considered for the cylindrical rod subjected to a tensile load of 29,000 N (6500 lb) with a maximum allowed elongation of 1.3 mm (0.05 in.)?",
|
||
"answer": "Copper is not considered due to its lower yield strength."
|
||
}
|
||
]
|
||
```
|
||
处理第 725/832 条数据...
|
||
[
|
||
{
|
||
"question": "A cylindrical metal specimen having an original diameter of 12.8 mm (0.505 in.) and gauge length of 50.80 mm (2.000 in.) is pulled in tension until fracture occurs. The diameter at the point of fracture is 8.13 mm (0.320 in.). Calculate the ductility in terms of percent reduction in area.",
|
||
"answer": "the ductility in terms of percent reduction in area is 60%."
|
||
},
|
||
{
|
||
"question": "A cylindrical metal specimen having an original diameter of 12.8 mm (0.505 in.) and gauge length of 50.80 mm (2.000 in.) is pulled in tension until fracture occurs. The fractured gauge length is 74.17 mm (2.920 in.). Calculate the ductility in terms of percent elongation.",
|
||
"answer": "the ductility in terms of percent elongation is 46%."
|
||
}
|
||
]
|
||
处理第 726/832 条数据...
|
||
It's a single issue.
|
||
处理第 727/832 条数据...
|
||
It's a single issue.
|
||
处理第 728/832 条数据...
|
||
It's a single issue.
|
||
处理第 729/832 条数据...
|
||
[
|
||
{
|
||
"question": "A three-point transverse bending test is conducted on a cylindrical specimen of aluminum oxide having a reported flexural strength of 300 MPa (43,500 psi). If the specimen radius is 5.0 mm (0.20 in.) and the support point separation distance is 15.0 mm (0.61 in.), would you expect the specimen to fracture when a load of 7500 N (1690 lbf) is applied? Justify your answer.",
|
||
"answer": "the flexural stress is 286.5 mpa. since this value is less than the flexural strength of 300 mpa, fracture is not predicted."
|
||
},
|
||
{
|
||
"question": "Would you be 100% certain of the answer in part (a)? Why or why not?",
|
||
"answer": "the certainty of this prediction is not 100% because there is always some variability in the flexural strength for ceramic materials, and the calculated stress is relatively close to the flexural strength, so there is some chance that fracture will occur."
|
||
}
|
||
]
|
||
处理第 730/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compute the modulus of elasticity for the nonporous material given that the modulus of elasticity for spinel (MgAl2O4) having 5 vol% porosity is 240 GPa (35 x 10^6 psi).",
|
||
"answer": "the modulus of elasticity for the nonporous material is 265 gpa (38.6 x 10^6 psi)."
|
||
},
|
||
{
|
||
"question": "Compute the modulus of elasticity for 15 vol% porosity given that the modulus of elasticity for spinel (MgAl2O4) having 5 vol% porosity is 240 GPa (35 x 10^6 psi).",
|
||
"answer": "the modulus of elasticity for 15 vol% porosity is 195 gpa (28.4 x 10^6 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 731/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compute the modulus of elasticity for the nonporous titanium carbide (TiC) given that the modulus of elasticity for titanium carbide (TiC) having 5 vol% porosity is 310 GPa (45 x 10^6 psi).",
|
||
"answer": "the modulus of elasticity for the nonporous material is 342 gpa (49.6 x 10^6 psi)."
|
||
},
|
||
{
|
||
"question": "At what volume percent porosity will the modulus of elasticity for titanium carbide (TiC) be 240 GPa (35 x 10^6 psi)?",
|
||
"answer": "the volume percent porosity at which the modulus of elasticity is 240 gpa (35 x 10^6 psi) is 17.1 vol%."
|
||
}
|
||
]
|
||
```
|
||
处理第 732/832 条数据...
|
||
[
|
||
{
|
||
"question": "The flexural strength and associated volume fraction porosity for two specimens of the same ceramic material are as follows: \begin{tabular}{ll} \hline \(\sigma_{f_{S}}(\mathbf{M P a})\) & \(\boldsymbol{P}\) \\ \hline 70 & 0.10 \\ 60 & 0.15 \\ \hline \end{tabular} (a) Compute the flexural strength for a completely nonporous specimen of this material.",
|
||
"answer": "the flexural strength for a completely nonporous specimen of this material is 95.3 mpa."
|
||
},
|
||
{
|
||
"question": "The flexural strength and associated volume fraction porosity for two specimens of the same ceramic material are as follows: \begin{tabular}{ll} \hline \(\sigma_{f_{S}}(\mathbf{M P a})\) & \(\boldsymbol{P}\) \\ \hline 70 & 0.10 \\ 60 & 0.15 \\ \hline \end{tabular} (b) Compute the flexural strength for a 0.20 volume fraction porosity.",
|
||
"answer": "the flexural strength for a 0.20 volume fraction porosity is 51.5 mpa."
|
||
}
|
||
]
|
||
API调用错误: Invalid \escape: line 3 column 167 (char 174)
|
||
处理第 733/832 条数据...
|
||
It's a single issue.
|
||
处理第 734/832 条数据...
|
||
It's a single issue.
|
||
处理第 735/832 条数据...
|
||
It's a single issue.
|
||
处理第 736/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the first criterion upon which factors of safety are based?",
|
||
"answer": "The first criterion is consequences of failure."
|
||
},
|
||
{
|
||
"question": "What is the second criterion upon which factors of safety are based?",
|
||
"answer": "The second criterion is previous experience."
|
||
},
|
||
{
|
||
"question": "What is the third criterion upon which factors of safety are based?",
|
||
"answer": "The third criterion is accuracy of measurement of mechanical forces and/or material properties."
|
||
},
|
||
{
|
||
"question": "What is the fourth criterion upon which factors of safety are based?",
|
||
"answer": "The fourth criterion is economics."
|
||
}
|
||
]
|
||
```
|
||
处理第 737/832 条数据...
|
||
It's a single issue.
|
||
处理第 738/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "A single crystal of zinc is oriented for a tensile test such that its slip plane normal makes an angle of 65 degrees with the tensile axis. Three possible slip directions make angles of 30 degrees, 48 degrees, and 78 degrees with the same tensile axis. Which of these three slip directions is most favored?",
|
||
"answer": "the most favored slip direction is at an angle of 30 degrees with the tensile axis."
|
||
},
|
||
{
|
||
"question": "A single crystal of zinc is oriented for a tensile test such that its slip plane normal makes an angle of 65 degrees with the tensile axis. The most favored slip direction makes an angle of 30 degrees with the same tensile axis. If plastic deformation begins at a tensile stress of 2.5 MPa (355 psi), determine the critical resolved shear stress for zinc.",
|
||
"answer": "the critical resolved shear stress for zinc is 0.91 mpa (130 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 739/832 条数据...
|
||
It's a single issue.
|
||
处理第 740/832 条数据...
|
||
It's a single issue.
|
||
处理第 741/832 条数据...
|
||
It's a single issue.
|
||
处理第 742/832 条数据...
|
||
It's a single issue.
|
||
处理第 743/832 条数据...
|
||
It's a single issue.
|
||
处理第 744/832 条数据...
|
||
[
|
||
{
|
||
"question": "What is the driving force for recrystallization?",
|
||
"answer": "The driving force for recrystallization is the difference in internal energy between the strained and unstrained material."
|
||
},
|
||
{
|
||
"question": "What is the driving force for grain growth?",
|
||
"answer": "The driving force for grain growth is the reduction in grain boundary energy as the total grain boundary area decreases."
|
||
}
|
||
]
|
||
处理第 745/832 条数据...
|
||
[
|
||
{
|
||
"question": "The average grain diameter for a brass material was measured as a function of time at 650 degrees C, which is shown in the following table at two different times: Time (min) 40, Grain Diameter (mm) 5.6 x 10^-2; Time (min) 100, Grain Diameter (mm) 8.0 x 10^-2. What was the original grain diameter?",
|
||
"answer": "the original grain diameter was 0.031 mm."
|
||
},
|
||
{
|
||
"question": "The average grain diameter for a brass material was measured as a function of time at 650 degrees C, which is shown in the following table at two different times: Time (min) 40, Grain Diameter (mm) 5.6 x 10^-2; Time (min) 100, Grain Diameter (mm) 8.0 x 10^-2. What grain diameter would you predict after 200 min at 650 degrees C?",
|
||
"answer": "the predicted grain diameter after 200 min at 650 degrees C is 0.109 mm."
|
||
}
|
||
]
|
||
处理第 746/832 条数据...
|
||
It's a single issue.
|
||
处理第 747/832 条数据...
|
||
It's a single issue.
|
||
处理第 748/832 条数据...
|
||
It's a single issue.
|
||
处理第 749/832 条数据...
|
||
It's a single issue.
|
||
处理第 750/832 条数据...
|
||
It's a single issue.
|
||
处理第 751/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Branched and atactic poly(vinyl chloride) with a weight-average molecular weight of 100,000 g/mol; linear and isotactic poly(vinyl chloride) having a weight-average molecular weight of 75,000 g/mol",
|
||
"answer": "Yes, it is possible. The linear and isotactic poly(vinyl chloride) will display a greater tensile modulus. Linear polymers are more likely to crystallize that branched ones. In addition, polymers having isotactic structures will normally have a higher degree of crystallinity that those having atactic structures. Increasing a polymer's crystallinity leads to an increase in its tensile modulus. In addition, tensile modulus is independent of molecular weight - the atactic/branched material has the higher molecular weight."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Random styrene-butadiene copolymer with 5% of possible sites crosslinked; block styrene-butadiene copolymer with 10% of possible sites crosslinked",
|
||
"answer": "Yes, it is possible. The block styrene-butadiene copolymer with 10% of possible sites crosslinked will have the higher modulus. Block copolymers normally have higher degrees of crystallinity than random copolymers of the same material. A higher degree of crystallinity favors larger moduli. In addition, the block copolymer also has a higher degree of crosslinking; increasing the amount of crosslinking also enhances the tensile modulus."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile modulus than the other; (2) if this is possible, note which has the higher tensile modulus and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Branched polyethylene with a number-average molecular weight of 100,000 g/mol; atactic polypropylene with a number-average molecular weight of 150,000 g/mol",
|
||
"answer": "No, it is not possible. Branched polyethylene will tend to have a low degree of crystallinity since branched polymers don't normally crystallize. The atactic polypropylene probably also has a relatively low degree of crystallinity; atactic structures also don't tend to crystallize, and polypropylene has a more complex repeat unit structure than does polyethylene.Tensile modulus increases with degree of crystallinity, and it is not possible to determine which polymer is more crystalline. Furthermore, tensile modulus is independent of molecular weight."
|
||
}
|
||
]
|
||
```
|
||
处理第 752/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Linear and isotactic poly(vinyl chloride) with a weight-average molecular weight of 100,000 g/mol; branched and atactic poly(vinyl chloride) having a weight-average molecular weight of 75,000 g/mol",
|
||
"answer": "Yes, it is possible. The linear and isotactic material will have the higher tensile strength. Both linearity and isotacticity favor a higher degree of crystallinity than do branching and atacticity; and tensile strength increases with increasing degree of crystallinity. Furthermore, the molecular weight of the linear/isotactic material is higher (100,000 g/mol versus 75,000 g/mol), and tensile strength increases with increasing molecular weight."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Graft acrylonitrile-butadiene copolymer with 10% of possible sites crosslinked; alternating acrylonitrile-butadiene copolymer with 5% of possible sites crosslinked",
|
||
"answer": "No, it is not possible. Alternating copolymers tend to be more crystalline than graft copolymers, and tensile strength increases with degree of crystallinity. However, the graft material has a higher degree of crosslinking, and tensile strength increases with the percentage of crosslinks."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to decide whether one polymer has a higher tensile strength than the other; (2) if this is possible, note which has the higher tensile strength and cite the reason(s) for your choice; and (3) if it is not possible to decide, state why. Network polyester; lightly branched polytetrafluoroethylene",
|
||
"answer": "Yes, it is possible. The network polyester will display a greater tensile strength. Relative chain motion is much more restricted than for the lightly branched polytetrafluoroethylene since there are many more of the strong covalent bonds for the network structure."
|
||
}
|
||
]
|
||
```
|
||
处理第 753/832 条数据...
|
||
It's a single issue.
|
||
处理第 754/832 条数据...
|
||
It's a single issue.
|
||
处理第 755/832 条数据...
|
||
It's a single issue.
|
||
处理第 756/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "An aircraft component is fabricated from an aluminum alloy that has a plane strain fracture toughness of 40 MPa sqrt(m) (36.4 ksi sqrt(in)). It has been determined that fracture results at a stress of 300 MPa (43,500 psi) when the maximum (or critical) internal crack length is 4.0 mm (0.16 in.). For this same component and alloy, will fracture occur at a stress level of 260 MPa (38,000 psi) when the maximum internal crack length is 6.0 mm (0.24 in.)? Why or why not?",
|
||
"answer": "fracture will occur since the value 42.4 MPa sqrt(m) is greater than the fracture toughness K_IC of the material, 40 MPa sqrt(m)."
|
||
}
|
||
]
|
||
```
|
||
处理第 757/832 条数据...
|
||
It's a single issue.
|
||
处理第 758/832 条数据...
|
||
It's a single issue.
|
||
处理第 759/832 条数据...
|
||
It's a single issue.
|
||
处理第 760/832 条数据...
|
||
It's a single issue.
|
||
处理第 761/832 条数据...
|
||
[
|
||
{
|
||
"question": "Why may there be significant scatter in the fracture strength for some given ceramic material?",
|
||
"answer": "There may be significant scatter in the fracture strength for some given ceramic material because the fracture strength depends on the probability of the existence of a flaw that is capable of initiating a crack; this probability varies from specimen to specimen of the same material."
|
||
},
|
||
{
|
||
"question": "Why does the fracture strength increase with decreasing specimen size?",
|
||
"answer": "The fracture strength increases with decreasing specimen size because as specimen size decreases, the probably of the existence of a flaw of that is capable of initiating a crack diminishes."
|
||
}
|
||
]
|
||
处理第 762/832 条数据...
|
||
It's a single issue.
|
||
处理第 763/832 条数据...
|
||
It's a single issue.
|
||
处理第 764/832 条数据...
|
||
[
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for tin.",
|
||
"answer": "for sn, -71°c or -96°f."
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for molybdenum.",
|
||
"answer": "for mo, 776°c or 1429°f."
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for iron.",
|
||
"answer": "for fe, 451°c or 845°f."
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for gold.",
|
||
"answer": "for au, 262°c or 504°f."
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for zinc.",
|
||
"answer": "for zn, 4°c or 39°f."
|
||
},
|
||
{
|
||
"question": "Give the approximate temperature at which creep deformation becomes an important consideration for chromium.",
|
||
"answer": "for cr, 586°c or 1087°f."
|
||
}
|
||
]
|
||
处理第 765/832 条数据...
|
||
It's a single issue.
|
||
处理第 766/832 条数据...
|
||
It's a single issue.
|
||
处理第 767/832 条数据...
|
||
It's a single issue.
|
||
处理第 768/832 条数据...
|
||
It's a single issue.
|
||
处理第 769/832 条数据...
|
||
It's a single issue.
|
||
处理第 770/832 条数据...
|
||
It's a single issue.
|
||
处理第 771/832 条数据...
|
||
It's a single issue.
|
||
处理第 772/832 条数据...
|
||
It's a single issue.
|
||
处理第 773/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly cite the differences among pearlite, bainite, and spheroidite relative to microstructure.",
|
||
"answer": "The microstructures of pearlite, bainite, and spheroidite all consist of α-ferrite and cementite phases. For pearlite, the two phases exist as layers, which alternate with one another. Bainite consists of very fine and parallel needle-shaped particles of cementite that are surrounded by an α-ferrite matrix. For spheroidite, the matrix is ferrite, and the cementite phase is in the shape of sphere-shaped particles."
|
||
},
|
||
{
|
||
"question": "Briefly cite the differences among pearlite, bainite, and spheroidite relative to mechanical properties.",
|
||
"answer": "Bainite is harder and stronger than pearlite, which, in turn, is harder and stronger than spheroidite."
|
||
}
|
||
]
|
||
处理第 774/832 条数据...
|
||
It's a single issue.
|
||
处理第 775/832 条数据...
|
||
It's a single issue.
|
||
处理第 776/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Branched polyethylene having a number-average molecular weight of 850,000 g/mol; linear polyethylene having a number-average molecular weight of 850,000 g/mol",
|
||
"answer": "Yes, it is possible to determine which polymer has the higher melting temperature. The linear polyethylene will most likely have a higher percent crystallinity, and, therefore, a higher melting temperature than the branched polyethylene. The molecular weights of both materials are the same and, thus, molecular weight is not a consideration."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Polytetrafluoroethylene having a density of 2.14 g/cm3 and a weight-average molecular weight of 600,000 g/mol; PTFE having a density of 2.20 g/cm3 and a weight-average molecular weight of 600,000 g/mol",
|
||
"answer": "Yes, it is possible to determine which polymer has the higher melting temperature. Of these two polytetrafluoroethylene polymers, the PTFE with the higher density (2.20 g/cm3) will have the higher percent crystallinity, and, therefore, a higher melting temperature than the lower density PTFE. The molecular weights of both materials are the same and, thus, molecular weight is not a consideration."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Linear and syndiotactic poly(vinyl chloride) having a number-average molecular weight of 500,000 g/mol; linear polyethylene having a number-average molecular weight of 225,000 g/mol",
|
||
"answer": "Yes, it is possible to determine which polymer has the higher melting temperature. The linear polyethylene will have the greater melting temperature inasmuch as it will have a higher degree of crystallinity; polymers having a syndiotactic structure do not crystallize as easily as those polymers having identical single-atom side groups. With regard to molecular weight, or rather, degree of polymerization, it is about the same for both materials (8000), and therefore, is not a consideration."
|
||
},
|
||
{
|
||
"question": "For the following pair of polymers, do the following: (1) state whether it is possible to determine whether one polymer has a higher melting temperature than the other; (2) if it is possible, note which has the higher melting temperature and then cite reason(s) for your choice; and (3) if it is not possible to decide, then state why. Linear and syndiotactic polypropylene having a weight-average molecular weight of 500,000 g/mol; linear and atactic polypropylene having a weight-average molecular weight of 750,000 g/mol",
|
||
"answer": "No, it is not possible to determine which of the two polymers has the higher melting temperature. The syndiotactic polypropylene will have a higher degree of crystallinity than the atactic material. On the basis of this effect alone, the syndiotactic PP should have the greater Tm, since melting temperature increases with degree of crystallinity. However, the molecular weight for the syndiotactic polypropylene (500,000 g/mol) is less than for the atactic material (750,000 g/mol); a lowering of molecular weight generally results in a reduction of melting temperature."
|
||
}
|
||
]
|
||
```
|
||
处理第 777/832 条数据...
|
||
[
|
||
{
|
||
"question": "Compute the electrical conductivity of a cylindrical silicon specimen 7.0 mm (0.28 in.) diameter and 57 mm (2.25 in.) in length in which a current of 0.25 A passes in an axial direction. A voltage of 24 V is measured across two probes that are separated by 45 mm (1.75 in.).",
|
||
"answer": "the electrical conductivity of the silicon specimen is 12.2 (omega \cdot m)^{-1}."
|
||
},
|
||
{
|
||
"question": "Compute the resistance over the entire 57 mm (2.25 in.) of the specimen.",
|
||
"answer": "the resistance over the entire specimen length is 121.4 omega."
|
||
}
|
||
]
|
||
API调用错误: Invalid \escape: line 4 column 87 (char 392)
|
||
处理第 778/832 条数据...
|
||
It's a single issue.
|
||
处理第 779/832 条数据...
|
||
It's a single issue.
|
||
处理第 780/832 条数据...
|
||
It's a single issue.
|
||
处理第 781/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Briefly state what is meant by the drift velocity of a free electron.",
|
||
"answer": "The drift velocity of a free electron is the average electron velocity in the direction of the force imposed by an electric field."
|
||
},
|
||
{
|
||
"question": "Briefly state what is meant by the mobility of a free electron.",
|
||
"answer": "The mobility is the proportionality constant between the drift velocity and the electric field. It is also a measure of the frequency of scattering events (and is inversely proportional to the frequency of scattering)."
|
||
}
|
||
]
|
||
```
|
||
处理第 782/832 条数据...
|
||
[
|
||
{
|
||
"question": "(a) Calculate the drift velocity of electrons in silicon at room temperature and when the magnitude of the electric field is 500 V/m.",
|
||
"answer": "the drift velocity of electrons in silicon at room temperature and when the magnitude of the electric field is 500 V/m is 72.5 m/s."
|
||
},
|
||
{
|
||
"question": "(b) Under these circumstances, how long does it take an electron to traverse a 25-mm length of crystal?",
|
||
"answer": "under these circumstances, it takes an electron 3.45 x 10^-4 s to traverse a 25-mm length of crystal."
|
||
}
|
||
]
|
||
处理第 783/832 条数据...
|
||
[
|
||
{
|
||
"question": "At room temperature the electrical conductivity and the electron mobility for aluminum are 3.8 x 10^7 (Ω·m)^-1 and 0.0012 m^2/V·s, respectively. Compute the number of free electrons per cubic meter for aluminum at room temperature.",
|
||
"answer": "the number of free electrons per cubic meter for aluminum at room temperature is 1.98 x 10^29 m^-3."
|
||
},
|
||
{
|
||
"question": "At room temperature the electrical conductivity and the electron mobility for aluminum are 3.8 x 10^7 (Ω·m)^-1 and 0.0012 m^2/V·s, respectively. What is the number of free electrons per aluminum atom? Assume a density of 2.7 g/cm^3.",
|
||
"answer": "the number of free electrons per aluminum atom is 3.28 electrons/al atom."
|
||
}
|
||
]
|
||
处理第 784/832 条数据...
|
||
It's a single issue.
|
||
处理第 785/832 条数据...
|
||
It's a single issue.
|
||
处理第 786/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Predict whether Nitrogen (N) will act as a donor or an acceptor when added to Silicon (Si). Assume that the impurity elements are substitutional.",
|
||
"answer": "Nitrogen will act as a donor in Si. Since it (N) is from group VA of the periodic table, and an N atom has one more valence electron than an Si atom."
|
||
},
|
||
{
|
||
"question": "Predict whether Boron (B) will act as a donor or an acceptor when added to Germanium (Ge). Assume that the impurity elements are substitutional.",
|
||
"answer": "Boron will act as an acceptor in Ge. Since it (B) is from group IIIA of the periodic table, a B atom has one less valence electron than a Ge atom."
|
||
},
|
||
{
|
||
"question": "Predict whether Sulfur (S) will act as a donor or an acceptor when added to Indium Antimonide (InSb). Assume that the impurity elements are substitutional.",
|
||
"answer": "Sulfur will act as a donor in InSb. Since S is from group VIA of the periodic table, it will substitute for Sb; an S atom has one more valence electron than an Sb atom."
|
||
},
|
||
{
|
||
"question": "Predict whether Indium (In) will act as a donor or an acceptor when added to Cadmium Sulfide (CdS). Assume that the impurity elements are substitutional.",
|
||
"answer": "Indium will act as a donor in CdS. Since In is from group IIIA of the periodic table, it will substitute for Cd; an In atom has one more valence electron than a Cd atom."
|
||
},
|
||
{
|
||
"question": "Predict whether Arsenic (As) will act as a donor or an acceptor when added to Zinc Telluride (ZnTe). Assume that the impurity elements are substitutional.",
|
||
"answer": "Arsenic will act as an acceptor in ZnTe. Since As is from group VA of the periodic table, it will substitute for Te; furthermore, an As atom has one less valence electron than a Te atom."
|
||
}
|
||
]
|
||
```
|
||
处理第 787/832 条数据...
|
||
[
|
||
{
|
||
"question": "Germanium to which 10^24 m^-3 As atoms have been added is an extrinsic semiconductor at room temperature, and virtually all the As atoms may be thought of as being ionized (i.e., one charge carrier exists for each As atom). Is this material n-type or p-type?",
|
||
"answer": "this germanium material to which has been added 10^24 m^-3 as atoms is n-type since as is a donor in ge."
|
||
},
|
||
{
|
||
"question": "Germanium to which 10^24 m^-3 As atoms have been added is an extrinsic semiconductor at room temperature, and virtually all the As atoms may be thought of as being ionized (i.e., one charge carrier exists for each As atom). Calculate the electrical conductivity of this material, assuming electron and hole mobilities of 0.1 and 0.05 m^2/V-s, respectively.",
|
||
"answer": "the conductivity is equal to 1.60 × 10^4 (ω·m)^-1."
|
||
}
|
||
]
|
||
处理第 788/832 条数据...
|
||
It's a single issue.
|
||
处理第 789/832 条数据...
|
||
It's a single issue.
|
||
处理第 790/832 条数据...
|
||
It's a single issue.
|
||
处理第 791/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Consider a parallel-plate capacitor having an area of 3225 mm2 (5 in.2), a plate separation of 1 mm (0.04 in.), and a material having a dielectric constant of 3.5 positioned between the plates. What is the capacitance of this capacitor?",
|
||
"answer": "the capacitance of this capacitor is 100 pf."
|
||
},
|
||
{
|
||
"question": "Consider a parallel-plate capacitor having an area of 3225 mm2 (5 in.2), a plate separation of 1 mm (0.04 in.), and a material having a dielectric constant of 3.5 positioned between the plates. Compute the electric field that must be applied for 2 × 10−8 C to be stored on each plate.",
|
||
"answer": "the electric field that must be applied is 2.0 × 105 v/m."
|
||
}
|
||
]
|
||
```
|
||
处理第 792/832 条数据...
|
||
[
|
||
{
|
||
"question": "The polarization P of a dielectric material positioned within a parallel-plate capacitor is to be 4.0 × 10^-6 C/m^2. What must be the dielectric constant if an electric field of 10^5 V/m is applied?",
|
||
"answer": "the dielectric constant εr must be 5.52."
|
||
},
|
||
{
|
||
"question": "The polarization P of a dielectric material positioned within a parallel-plate capacitor is to be 4.0 × 10^-6 C/m^2. What will be the dielectric displacement D?",
|
||
"answer": "the dielectric displacement d will be 4.89 × 10^-6 c/m^2."
|
||
}
|
||
]
|
||
处理第 793/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For each of the three types of polarization, briefly describe the mechanism by which dipoles are induced and/or oriented by the action of an applied electric field.",
|
||
"answer": "For electronic polarization, the electric field causes a net displacement of the center of the negatively charged electron cloud relative to the positive nucleus. With ionic polarization, the cations and anions are displaced in opposite directions as a result of the application of an electric field. Orientation polarization is found in substances that possess permanent dipole moments; these dipole moments become aligned in the direction of the electric field."
|
||
},
|
||
{
|
||
"question": "For gaseous argon, solid LiF, liquid H2O, and solid Si, what kind(s) of polarization is (are) possible? Why?",
|
||
"answer": "Only electronic polarization is found in gaseous argon; being an inert gas, its atoms will not be ionized nor possess permanent dipole moments. Both electronic and ionic polarizations are found in solid LiF, since it is strongly ionic. In all probability, no permanent dipole moments will be found in this material. Both electronic and orientation polarizations are found in liquid H2O. The H2O molecules have permanent dipole moments that are easily oriented in the liquid state. Only electronic polarization is to be found in solid Si; this material does not have molecules with permanent dipole moments, nor is it an ionic material."
|
||
}
|
||
]
|
||
```
|
||
处理第 794/832 条数据...
|
||
[
|
||
{
|
||
"question": "List the four classifications of steels.",
|
||
"answer": "The four classifications of steels are: Low Carbon Steels, Medium Carbon Steels, High Carbon Steels, and High Alloy Steels (Stainless and Tool)."
|
||
},
|
||
{
|
||
"question": "For Low Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: nonresponsive to heat treatments; relatively soft and weak; machinable and weldable. Typical applications: automobile bodies, structural shapes, pipelines, buildings, bridges, and tin cans."
|
||
},
|
||
{
|
||
"question": "For Medium Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: heat treatable, relatively large combinations of mechanical characteristics. Typical applications: railway wheels and tracks, gears, crankshafts, and machine parts."
|
||
},
|
||
{
|
||
"question": "For High Carbon Steels, briefly describe the properties and typical applications.",
|
||
"answer": "Properties: hard, strong, and relatively brittle. Typical applications: chisels, hammers, knives, and hacksaw blades."
|
||
},
|
||
{
|
||
"question": "For High Alloy Steels (Stainless and Tool), briefly describe the properties and typical applications.",
|
||
"answer": "Properties: hard and wear resistant; resistant to corrosion in a large variety of environments. Typical applications: cutting tools, drills, cutlery, food processing, and surgical tools."
|
||
}
|
||
]
|
||
处理第 795/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Compare gray and malleable cast irons with respect to composition and heat treatment",
|
||
"answer": "Gray iron--2.5 to 4.0 wt% C and 1.0 to 3.0 wt% Si. For most gray irons there is no heat treatment after solidification. Malleable iron--2.5 to 4.0 wt% C and less than 1.0 wt% Si. White iron is heated in a nonoxidizing atmosphere and at a temperature between 800 and 900°C for an extended time period."
|
||
},
|
||
{
|
||
"question": "Compare gray and malleable cast irons with respect to microstructure",
|
||
"answer": "Gray iron--Graphite flakes are embedded in a ferrite or pearlite matrix. Malleable iron--Graphite clusters are embedded in a ferrite or pearlite matrix."
|
||
},
|
||
{
|
||
"question": "Compare gray and malleable cast irons with respect to mechanical characteristics",
|
||
"answer": "Gray iron--Relatively weak and brittle in tension; good capacity for damping vibrations. Malleable iron--Moderate strength and ductility."
|
||
}
|
||
]
|
||
```
|
||
处理第 796/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What are the distinctive features, limitations, and applications of titanium alloys?",
|
||
"answer": "Distinctive features: relatively low density, high melting temperatures, and high strengths are possible. Limitation: because of chemical reactivity with other materials at elevated temperatures, these alloys are expensive to refine. Applications: aircraft structures, space vehicles, and in chemical and petroleum industries."
|
||
},
|
||
{
|
||
"question": "What are the distinctive features, limitations, and applications of refractory metals?",
|
||
"answer": "Distinctive features: extremely high melting temperatures; large elastic moduli, hardnesses, and strengths. Limitation: some experience rapid oxidation at elevated temperatures. Applications: extrusion dies, structural parts in space vehicles, incandescent light filaments, x-ray tubes, and welding electrodes."
|
||
},
|
||
{
|
||
"question": "What are the distinctive features, limitations, and applications of superalloys?",
|
||
"answer": "Distinctive features: able to withstand high temperatures and oxidizing atmospheres for long time periods. Applications: aircraft turbines, nuclear reactors, and petrochemical equipment."
|
||
},
|
||
{
|
||
"question": "What are the distinctive features, limitations, and applications of noble metals?",
|
||
"answer": "Distinctive features: highly resistant to oxidation, especially at elevated temperatures; soft and ductile. Limitation: expensive. Applications: jewelry, dental restoration materials, coins, catalysts, and thermocouples."
|
||
}
|
||
]
|
||
```
|
||
处理第 797/832 条数据...
|
||
[
|
||
{
|
||
"question": "For the MgO-Al2O3 system, what is the maximum temperature that is possible without the formation of a liquid phase?",
|
||
"answer": "This problem asks that we specify, for the MgO-Al2O3 system, the maximum temperature without the formation of a liquid phase; it is approximately 2800 degrees Celsius."
|
||
},
|
||
{
|
||
"question": "For the MgO-Al2O3 system, at what composition or over what range of compositions will this maximum temperature be achieved?",
|
||
"answer": "This maximum temperature is possible for pure MgO."
|
||
}
|
||
]
|
||
处理第 798/832 条数据...
|
||
[
|
||
{
|
||
"question": "What are the characteristics of sand casting technique?",
|
||
"answer": "For sand casting, sand is the mold material, a two-piece mold is used, ordinarily the surface finish is not an important consideration, the sand may be reused (but the mold may not), casting rates are low, and large pieces are usually cast."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of die casting technique?",
|
||
"answer": "For die casting, a permanent mold is used, casting rates are high, the molten metal is forced into the mold under pressure, a two-piece mold is used, and small pieces are normally cast."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of investment casting technique?",
|
||
"answer": "For investment casting, a single-piece mold is used, which is not reusable; it results in high dimensional accuracy, good reproduction of detail, and a fine surface finish; and casting rates are low."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of lost-foam casting technique?",
|
||
"answer": "For lost foam casting, the pattern is polystyrene foam, whereas the mold material is sand. Complex geometries and tight tolerances are possible. Casting rates are higher than for investment, and there are few environmental wastes."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of continuous casting technique?",
|
||
"answer": "For continuous casting, at the conclusion of the extraction process, the molten metal is cast into a continuous strand having either a rectangular or circular cross-section; these shapes are desirable for subsequent secondary metal-forming operations. The chemical composition and mechanical properties are relatively uniform throughout the cross-section."
|
||
}
|
||
]
|
||
处理第 799/832 条数据...
|
||
It's a single issue.
|
||
处理第 800/832 条数据...
|
||
It's a single issue.
|
||
处理第 801/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is the process of compression molding used to form plastic materials?",
|
||
"answer": "For compression molding, both heat and pressure are applied after the polymer and necessary additives are situated between the mold members."
|
||
},
|
||
{
|
||
"question": "What is the process of transfer molding used to form plastic materials?",
|
||
"answer": "For transfer molding, the solid materials (normally thermosetting in nature) are first melted in the transfer chamber prior to being forced into the die."
|
||
},
|
||
{
|
||
"question": "What is the process of injection molding used to form plastic materials?",
|
||
"answer": "For injection molding (normally used for thermoplastic materials), the raw materials are impelled by a ram through a heating chamber, and finally into the die cavity."
|
||
}
|
||
]
|
||
```
|
||
处理第 802/832 条数据...
|
||
[
|
||
{
|
||
"question": "Why must fiber materials that are melt-spun be thermoplastic?",
|
||
"answer": "Fiber materials that are melt spun must be thermoplastic because they must be capable of forming a viscous liquid when heated, which is not possible for thermosets."
|
||
},
|
||
{
|
||
"question": "Why must fiber materials that are drawn be thermoplastic?",
|
||
"answer": "Fiber materials that are drawn must be thermoplastic because during drawing, mechanical elongation must be possible; inasmuch as thermosetting materials are, in general, hard and relatively brittle, they are not easily elongated."
|
||
}
|
||
]
|
||
处理第 803/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Estimate the maximum thermal conductivity value for a cermet that contains 90 vol% titanium carbide (TiC) particles in a nickel matrix. Assume thermal conductivities of 27 and 67 W/m·K for TiC and Ni, respectively.",
|
||
"answer": "the maximum thermal conductivity k_max is 31.0 W/m·K."
|
||
},
|
||
{
|
||
"question": "Estimate the minimum thermal conductivity value for a cermet that contains 90 vol% titanium carbide (TiC) particles in a nickel matrix. Assume thermal conductivities of 27 and 67 W/m·K for TiC and Ni, respectively.",
|
||
"answer": "the minimum thermal conductivity k_min is 28.7 W/m·K."
|
||
}
|
||
]
|
||
```
|
||
处理第 804/832 条数据...
|
||
It's a single issue.
|
||
处理第 805/832 条数据...
|
||
It's a single issue.
|
||
处理第 806/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "In an aligned and continuous carbon fiber-reinforced nylon 6,6 composite, the fibers are to carry 97% of a load applied in the longitudinal direction. Using the data provided, determine the volume fraction of fibers required.",
|
||
"answer": "the volume fraction of fibers required is 0.258."
|
||
},
|
||
{
|
||
"question": "In an aligned and continuous carbon fiber-reinforced nylon 6,6 composite, the fibers are to carry 97% of a load applied in the longitudinal direction. What will be the tensile strength of this composite? Assume that the matrix stress at fiber failure is 50 MPa (7250 psi).",
|
||
"answer": "the tensile strength of this composite is 1070 mpa (155,000 psi)."
|
||
}
|
||
]
|
||
```
|
||
处理第 807/832 条数据...
|
||
[
|
||
{
|
||
"question": "Cite several reasons why fiberglass-reinforced composites are used extensively.",
|
||
"answer": "Reasons why fiberglass-reinforced composites are utilized extensively are: (1) glass fibers are very inexpensive to produce; (2) these composites have relatively high specific strengths; and (3) they are chemically inert in a wide variety of environments."
|
||
},
|
||
{
|
||
"question": "Cite several limitations of fiberglass-reinforced composites.",
|
||
"answer": "Several limitations of these composites are: (1) care must be exercised in handling the fibers inasmuch as they are susceptible to surface damage; (2) they are lacking in stiffness in comparison to other fibrous composites; and (3) they are limited as to maximum temperature use."
|
||
}
|
||
]
|
||
处理第 808/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "What is a hybrid composite?",
|
||
"answer": "A hybrid composite is a composite that is reinforced with two or more different fiber materials in a single matrix."
|
||
},
|
||
{
|
||
"question": "List two important advantages of hybrid composites over normal fiber composites.",
|
||
"answer": "Two advantages of hybrid composites are: (1) better overall property combinations, and (2) failure is not as catastrophic as with single-fiber composites."
|
||
}
|
||
]
|
||
```
|
||
处理第 809/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Write an expression for the modulus of elasticity for a hybrid composite in which all fibers of both types are oriented in the same direction.",
|
||
"answer": "the expression for the modulus of elasticity for a hybrid composite with all fibers aligned in the same direction is: e_cl = e_m v_m + e_f1 v_f1 + e_f2 v_f2"
|
||
},
|
||
{
|
||
"question": "(b) Using this expression, compute the longitudinal modulus of elasticity of a hybrid composite consisting of aramid and glass fibers in volume fractions of 0.25 and 0.35 , respectively, within a polyester resin matrix [E_m=4.0 GPa (6x10^5 psi)].",
|
||
"answer": "the longitudinal modulus of elasticity of the hybrid composite is: e_cl = 59.7 gpa (8.67x10^6 psi)"
|
||
}
|
||
]
|
||
```
|
||
处理第 810/832 条数据...
|
||
[
|
||
{
|
||
"question": "Briefly describe laminar composites.",
|
||
"answer": "Laminar composites are a series of sheets or panels, each of which has a preferred high-strength direction. These sheets are stacked and then cemented together such that the orientation of the high-strength direction varies from layer to layer."
|
||
},
|
||
{
|
||
"question": "What is the prime reason for fabricating laminar composites?",
|
||
"answer": "These composites are constructed in order to have a relatively high strength in virtually all directions within the plane of the laminate."
|
||
}
|
||
]
|
||
处理第 811/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Is a voltage generated between the two cell halves of an Fe/Fe2+ concentration cell where both electrodes are pure iron, with Fe2+ concentrations of 0.5 M and 2 × 10^-2 M?",
|
||
"answer": "Yes, a voltage is generated."
|
||
},
|
||
{
|
||
"question": "What is the magnitude of the voltage generated in an Fe/Fe2+ concentration cell with Fe2+ concentrations of 0.5 M and 2 × 10^-2 M?",
|
||
"answer": "The magnitude of the voltage is 0.0414 V."
|
||
},
|
||
{
|
||
"question": "Which electrode will be oxidized in an Fe/Fe2+ concentration cell with Fe2+ concentrations of 0.5 M and 2 × 10^-2 M?",
|
||
"answer": "Oxidation occurs in the cell half with the lower Fe2+ concentration (2 × 10^-2 M)."
|
||
}
|
||
]
|
||
```
|
||
处理第 812/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the aluminum and cast iron pair that are coupled in seawater, predict the possibility of corrosion; if corrosion is probable, note which metal/alloy will corrode.",
|
||
"answer": "For the aluminum-cast iron couple, corrosion is possible, and aluminum will corrode."
|
||
},
|
||
{
|
||
"question": "For the Inconel and nickel pair that are coupled in seawater, predict the possibility of corrosion; if corrosion is probable, note which metal/alloy will corrode.",
|
||
"answer": "For the Inconel-nickel couple, corrosion is unlikely inasmuch as both alloys appear within the same set of brackets (in both active and passive states)."
|
||
},
|
||
{
|
||
"question": "For the cadmium and zinc pair that are coupled in seawater, predict the possibility of corrosion; if corrosion is probable, note which metal/alloy will corrode.",
|
||
"answer": "For the cadmium-zinc couple, corrosion is possible, and zinc will corrode."
|
||
},
|
||
{
|
||
"question": "For the brass and titanium pair that are coupled in seawater, predict the possibility of corrosion; if corrosion is probable, note which metal/alloy will corrode.",
|
||
"answer": "For the brass-titanium pair, corrosion is possible, and brass will corrode."
|
||
},
|
||
{
|
||
"question": "For the low-carbon steel and copper pair that are coupled in seawater, predict the possibility of corrosion; if corrosion is probable, note which metal/alloy will corrode.",
|
||
"answer": "For the low-carbon steel-copper couple, corrosion is possible, and the low-carbon steel will corrode."
|
||
}
|
||
]
|
||
```
|
||
处理第 813/832 条数据...
|
||
It's a single issue.
|
||
处理第 814/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "Assuming that activation polarization controls both oxidation and reduction reactions, determine the rate of corrosion of metal M (in mol/cm^2-s). The following corrosion data are known about the metal and solution: For Metal M: V_(MM^2+) = -0.90 V, i_0 = 10^-12 A/cm^2, beta = +0.10. For Hydrogen: V_(H^-/H_2) = 0 V, i_0 = 10^-10 A/cm^2.",
|
||
"answer": "the rate of corrosion of metal M is 3.27 x 10^-13 mol/cm^2-s."
|
||
},
|
||
{
|
||
"question": "Compute the corrosion potential for this reaction. The following corrosion data are known about the metal and solution: For Metal M: V_(MM^2+) = -0.90 V, i_0 = 10^-12 A/cm^2, beta = +0.10. For Hydrogen: V_(H^-/H_2) = 0 V, i_0 = 10^-10 A/cm^2.",
|
||
"answer": "the corrosion potential for this reaction is -0.420 V."
|
||
}
|
||
]
|
||
```
|
||
处理第 815/832 条数据...
|
||
It's a single issue.
|
||
处理第 816/832 条数据...
|
||
It's a single issue.
|
||
处理第 817/832 条数据...
|
||
[
|
||
{
|
||
"question": "For copper, the heat capacity at constant volume C_V at 20 K is 0.38 J/mol-K and the Debye temperature is 340 K. Estimate the specific heat at 40 K.",
|
||
"answer": "the specific heat for copper at 40 K is 47.8 J/kg-K."
|
||
},
|
||
{
|
||
"question": "For copper, the heat capacity at constant volume C_V at 20 K is 0.38 J/mol-K and the Debye temperature is 340 K. Estimate the specific heat at 400 K.",
|
||
"answer": "the specific heat for copper at 400 K is 392 J/kg-K."
|
||
}
|
||
]
|
||
处理第 818/832 条数据...
|
||
It's a single issue.
|
||
处理第 819/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Pure silver; sterling silver (92.5 wt% Ag-7.5 wt% Cu)",
|
||
"answer": "Pure silver will have a larger conductivity than sterling silver because the impurity atoms in the latter will lead to a greater degree of free electron scattering."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Fused silica; polycrystalline silica",
|
||
"answer": "Polycrystalline silica will have a larger conductivity than fused silica because fused silica is noncrystalline and lattice vibrations are more effectively scattered in noncrystalline materials."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Linear and syndiotactic poly(vinyl chloride) (DP =1000); linear and syndiotactic polystyrene (DP=1000)",
|
||
"answer": "The poly(vinyl chloride) will have the larger conductivity than the polystyrene because the former will have the higher degree of crystallinity. Both polymers are syndiotactic and have the same degree of polymerization. However, with regard to side-group bulkiness, the PVC is more likely to crystallize. Since heat transfer is by molecular chain vibrations, and the coordination of these vibrations increases with percent crystallinity, the higher the crystallinity, the greater the thermal conductivity."
|
||
},
|
||
{
|
||
"question": "For the following pair of materials, decide which has the larger thermal conductivity. Justify your choice. Atactic polypropylene (Mw=10^6 g/mol); isotactic polypropylene (Mw=10^5 g/mol)",
|
||
"answer": "The isotactic polypropylene will have a larger thermal conductivity than the atactic polypropylene because isotactic polymers have higher degrees of crystallinity. The influence of crystallinity on conductivity is explained in part (c)."
|
||
}
|
||
]
|
||
```
|
||
处理第 820/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "(a) Briefly explain why thermal stresses may be introduced into a structure by rapid heating or cooling.",
|
||
"answer": "Thermal stresses may be introduced into a structure by rapid heating or cooling because temperature gradients are established across the cross section due to more rapid temperature changes at the surface than within the interior; thus, the surface will expand or contract at a different rate than the interior and since this surface expansion or contraction will be restrained by the interior, stresses will be introduced."
|
||
},
|
||
{
|
||
"question": "(b) For cooling, what is the nature of the surface stresses?",
|
||
"answer": "For cooling, the surface stresses will be tensile in nature since the interior contracts to a lesser degree than the cooler surface."
|
||
},
|
||
{
|
||
"question": "(c) For heating, what is the nature of the surface stresses?",
|
||
"answer": "For heating, the surface stresses will be compressive in nature since the interior expands to a lesser degree than the hotter surface."
|
||
}
|
||
]
|
||
```
|
||
处理第 821/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "The magnetic flux density within a bar of some material is 0.630 tesla at an H field of 5 x 10^5 A/m. Compute the magnetic permeability for this material.",
|
||
"answer": "1.260 x 10^-6 h/m."
|
||
},
|
||
{
|
||
"question": "The magnetic flux density within a bar of some material is 0.630 tesla at an H field of 5 x 10^5 A/m. Compute the magnetic susceptibility for this material.",
|
||
"answer": "2.387 x 10^-3."
|
||
},
|
||
{
|
||
"question": "The magnetic flux density within a bar of some material is 0.630 tesla at an H field of 5 x 10^5 A/m. What type(s) of magnetism would you suggest is (are) being displayed by this material? Why?",
|
||
"answer": "This material would display both diamagnetic and paramagnetic behavior. All materials are diamagnetic, and since χm is positive and on the order of 10^-3, there would also be a paramagnetic contribution."
|
||
}
|
||
]
|
||
```
|
||
处理第 822/832 条数据...
|
||
It's a single issue.
|
||
处理第 823/832 条数据...
|
||
It's a single issue.
|
||
处理第 824/832 条数据...
|
||
```json
|
||
[
|
||
{
|
||
"question": "The formula for samarium iron garnet (Sm3Fe5O12) may be written in the form Sm3^aFe2^cFe3^dO12, where the superscripts a, c, and d represent different sites on which the Sm^3+ and Fe^3+ ions are located. The spin magnetic moments for the Sm^3+ and Fe^3+ ions positioned in a and c sites are oriented parallel to one another and antiparallel to the Fe^3+ ions in d sites. Compute the number of Bohr magnetons associated with each Sm^3+ ion, given the following information: (1) each unit cell consists of eight formula (Sm3Fe5O12) units; (2) the unit cell is cubic with an edge length of 1.2529 nm; (3) the saturation magnetization for this material is 1.35 × 10^5 A/m; and (4) there are 5 Bohr magnetons associated with each Fe^3+ ion.",
|
||
"answer": "2.86 bm."
|
||
}
|
||
]
|
||
```
|
||
处理第 825/832 条数据...
|
||
It's a single issue.
|
||
处理第 826/832 条数据...
|
||
It's a single issue.
|
||
处理第 827/832 条数据...
|
||
It's a single issue.
|
||
处理第 828/832 条数据...
|
||
[
|
||
{
|
||
"question": "Visible light having a wavelength of 5 x 10^-7 m appears green. Compute the frequency of a photon of this light.",
|
||
"answer": "the frequency of the photon is 6 x 10^14 s^-1."
|
||
},
|
||
{
|
||
"question": "Visible light having a wavelength of 5 x 10^-7 m appears green. Compute the energy of a photon of this light.",
|
||
"answer": "the energy of the photon is 3.98 x 10^-19 j (2.48 ev)."
|
||
}
|
||
]
|
||
处理第 829/832 条数据...
|
||
[
|
||
{
|
||
"question": "What are the characteristics of opaque materials in terms of their appearance and light transmittance?",
|
||
"answer": "Opaque materials are impervious to light transmission; it is not possible to see through them."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of translucent materials in terms of their appearance and light transmittance?",
|
||
"answer": "Light is transmitted diffusely through translucent materials (there is some internal light scattering). Objects are not clearly distinguishable when viewed through a translucent material."
|
||
},
|
||
{
|
||
"question": "What are the characteristics of transparent materials in terms of their appearance and light transmittance?",
|
||
"answer": "Virtually all of the incident light is transmitted through transparent materials, and one can see clearly through them."
|
||
}
|
||
]
|
||
处理第 830/832 条数据...
|
||
It's a single issue.
|
||
处理第 831/832 条数据...
|
||
It's a single issue.
|
||
处理第 832/832 条数据...
|
||
It's a single issue.
|
||
处理完成，结果已保存到 single_select.json
|