已选分类
工学
多选题水型物质在熔融成液态时，其体积发生______现象。
a.膨胀
b.收缩
c.不变
多选题钢中的奥氏体：
多选题金刚石的晶体结构为______，其中碳原子的配位数是______。
a．面心立方格子b．简单立方格子c．体心立方格子 d．3
e．4 f．6 g．8
多选题金属断裂的断口特征：
多选题固态扩散：
多选题The key word in describing ionic bonding is ______. A) Transferring B) Sharing C) Swapping D) Swarming
多选题铁碳合金平衡相图：
多选题Which of the following statement about the diffusion of atoms, molecules or ions is NOT correct? A) The rate of diffusion will decrease with an increase in temperature. B) A lattice structure that contains loosely packed atoms (less dense) will offer greater resistance to diffusing atoms than one whose structure contains tightly packed atoms. C) The stronger the bonding forces between the atoms the more difficult for the atoms to diffuse. D) Smaller permeating atoms stand better chance of diffusion through a structure oflarger atoms.
多选题与玻璃软化温度Tf相对应的粘度为______。
a.105dPa·s
b.109dPa·s
c.1011dPa·s
d.1013dPa·s
多选题在同一体系和相同的过冷度下，非均匀成核速率总是______均匀成核速率。
a.大于或等于
b.小于或等于
c.等于
d.不一定
多选题______ is not a structural adhesive. A) casein B) urea-formaldehyde C) phenol-resorcinol-formaldehyde D) poly (vinyl acetate)
多选题What terms describe cross-linking in rubber? A) netting index B) vulcanization C) polymerization D) hardness
多选题在七大晶系中属于高级晶族的晶系有______。
a.1个
b.2个
c.3个
d.4个
多选题菲克第一定律可直接用于求解______的问题。
a.稳定扩散
b.不稳定扩散
c.任何扩散
多选题在下列几类晶体中，形成间隙型固溶体的次序是______。
a.沸石＞CaF2＞TiO2＞MgO
b.MgO＞TiO2＞CaF2＞沸石
c.CaF2TiO2＞MgO＞沸石
d.TiO2＞MgO＞CaF2＞沸石
多选题Which ofthe following comparison is not correct? A) Thermal conductivity: metal ＜ plastics B) Thermal expansion: metal ＞ plastics C) Density: metal ＞ plastics D) Thermal conductivity: metal ＞ plastics
多选题The adhesive can achieve wetting on an adherend when ______. A) The adhesive have a surface tension greater than the adhesive forces between the adherend and adhesive. B) The adhesive must have surface energy lower than does the adherend have. C) The adhesive must have zero or very small contact angle. D) The adhesive must not have cohesive forces.
多选题在低温下，一般固体材料中发生的扩散是______。
a.本征扩散
b.非本征扩散
c.无序扩散
多选题An elastomer has physical cross-links in the network structure. A) NR B) SBS C) SIS D) NBR
多选题矿渣水泥适用于( )的混凝土工程。 A．抗渗性要求较高 B．早期强度要求较高 C．大体积 D．耐热 E．软水侵蚀