已选分类
工学材料科学与工程
单选题在晶体中形成空位的同时又产生间隙原子，这样的缺陷称为______。
单选题在SiO2七种晶型(polymorphic form)转变中，存在两种转变方式：一种为位移转变(displacive transformation)，另一种为重构转变(reconstructive transformation)，位移转变需要的激活能(activation energy)______重构转变的激活能。
单选题在柯肯达尔效应中，标记漂移主要原因是扩散偶中______。 (A) 两组元的原子尺寸不同 (B) 仅一组元的扩散 (C) 两组元的扩散速率不同
单选题离子晶体中阳离子比阴离子扩散速率______。
单选题在面心立方晶体中(111)密排面抽取一层将形成______。
单选题A和A-B合金焊合后发生柯肯达尔效应，测得界面向A试样方向移动，则______。
单选题Directional properties in fiber composites are achieved mainly due to ______. A．fiber orientation B．laminate plane C．interphase D．prepregs
单选题______ is not a chemical reaction in which simple molecules are added to each other to form long chain molecules without by products. A．Addition polymerization B．Condensation polymerization C．Ring-opening polymerization D．Bulk polymerization
单选题室温下橡胶与塑料的不同柔顺性表明______。
单选题形变后的材料再升温时发生回复和再结晶现象，则点缺陷浓度下降明显发生在______。
单选题影响钢的淬透性的决定性因素是( )。 A．钢的临界冷却速度 B．工件尺寸的大小 C．淬火介质冷却能力 D．钢的含碳量
单选题______ crystal system has mutually perpendicular axes (α=β=γ=90°) but unequal lattice parameters, among which the z-intercept is larger than the x- or y- intercepts (c＞a=b). A) Cubic B) Hexagonal C) Monoclinic D) Tetragonal
单选题作为塑料使用的高分子，在室温使用应处在______。
单选题______ is the amount of heat necessary to raise the temperature of exactly one gram of a material by exactly one degree (1℃ or 1K). A) Heat capacity B) Specific heat C) Thermal conductivity D) Coefficient of thermal expansion
单选题下述有关自扩散的描述中正确的为______。
单选题立方晶体中含有[111]晶向的晶面为______。
单选题在RO-SiO2的系统中：(1)MgO-SiO2；(2)CaO-SiO2；(3)SrO-SiO2；(4)BaO-SiO2的分相区范围的大小次序为______。
A.(1)＞(2)＞(3)＞(4)
B.(4)＞(3)＞(2)＞(1)
C.(2)＞(1)＞(3)＞(4)
D.(3)＞(4)＞(2)＞(1)
单选题Which ofthe followings is a continuous fiber composite processing? A) Compression molding B) Reaction inj ection molding C) Resin transfer molding D) Filament winding
单选题有序一无序转变是指晶体与非晶体之间的转变。
单选题Which statement is false concerning the objectives of applying coupling agent onto fiber? A．To protect the fiber surface from damage and bind fibers together for ease of processing. B．To lubricate the fibers for less abrasion during subsequent processing operations. C．To impart thermal and electric conductivity. D．To provide a chemicallink between the fiber surface and the matrix and improve the bonding at the interface.