已选分类
工学材料科学与工程
单选题肖特基(Schottky)型空位表示形成______的无序分布缺陷。
单选题在非化学计量化合物UO2+x中存在的晶格缺陷是______。 A．阴离子空位 B．阳离子空位 C．阴离子填隙 D．阳离子填隙
单选题晶体长大时如生长速率与动态过冷度成正比，则______
单选题______ is a transparent crystalline carbon. A) Graphite B) Coke C) Diamond D) Charcoal
单选题
高分子链能产生不同构象的根本原因是________。
A、氢键的内旋转 B、键的内旋转 C、键的内旋转
单选题形成临界晶核(critical nucleus)时体积自由能(volume free energy)的减少只能补偿表面能(surface energy)的______。
单选题相图表示的是体系的热力学平衡状态。
单选题Which ofthe following is the type ofbond holding Na+ and Cl- ions in NaCl? A) Ionicbond B) Covalentbond C) Hydrogenbond D) Metallicbond
单选题______ is a measure of heat flow through a material. It relates heat flow (the flow of heat energy per unit area, per unit time) to the temperature gradient, causing the heat to flow. A) Heatcapacity B) Specificheat C) Thermalconductivity D) Coefficient ofthermal expansion
单选题能进行攀移的位错可能是______。
单选题Which of the following substance is not used to produce carbon fibers? A) Rayon B) Polyacrylonitrile C) Pitch D) Pregreg
单选题______ retain their fluid state when exposed to oxygen, but when squeezed into thin joints that block the oxygen, they set up into hard, strong adhesives. A) Hot-melt adhesives B) Loss-of solvent adhesives C) Anaerobic adhesives D) Two-part mix adhesives
单选题在fcc、bcc和hcp三种单晶材料中，形变时各向异性行为最显著的是______。
单选题灰口铸铁，为获得高的耐磨性，应选用( )。 A．孕育处理 B．正火 C．表面淬火
单选题Which concept of the materials cycle has been LEAST AFFECTED by recent trends? A) Concern for the entire cycle that includes effects of harmful by-products and unrecycled old products B) Ability to design materials to meet ever-increasing demands of technology rather than use off-the shelf materials C) Need for a more highly educated workforce to support new manufacturing techniques D) Desire to achieve the maximum properties from any given materials
单选题共晶层片(α+β)共在特定过冷度下生长时，扩散所消耗的驱动力约为______。
单选题在合金非平衡凝固中将会产生各种成分偏析，其中最难消除的偏析是______。
单选题在低碳钢的应力一应变曲线中出现上屈服点和下屈服的的现象，可用______解释。
单选题______ is a homogeneous mixture of chemically distinct substances that forms a phase. The components (substances) lose their individual identities. A) Alloy B) Solute C) Solution D) Solvent
单选题Hollow products (barrels, bottles, tanks) can be produced through ______. A．extrusion B．blowing molding C．compression molding D．calendering