已选分类
工学材料科学与工程
单选题Which statement of elements is NOT correct? A) An element is a substance whose atoms all have the same atomic number. B) The atoms ofan element all contain the same number ofprotons C) The atoms ofan element all contain the same numbers of neutrons D) An element is a substance that cannot be broken down any further by chemical reaction
单选题The maximum number of electrons in the M energy level is ______. A) 2 B) 8 C) 18 D) 32
单选题根据三元相图的垂直截面图，可以______。 (A) 分析相成分的变化规律 (B) 分析合金的凝固过程 (C) 用杠杆法则计算各相的相对量
单选题四元合金在常压下，其恒温转变时应为______平衡。
单选题______ are composites with a substance that is reinforced with nanometer size particles which enhance the substrates physical properties A．Foam composites B．Laminar composites C．Nanocomposites D．Sandwich composites
单选题The following compounds are all unsaturated hydrocarbons except______ A) Acetylene B) Alkenes C) Alkynes D) Methane
单选题空间群为Fm3m的晶体结构属于{{U}} (A) {{/U}}晶族，{{U}} (B) {{/U}}晶系。
a．高级 b．中级 c．低级 d．等轴
e．六方 f．四方 g．正交
单选题在尖晶石(MgAl
2
O
3
)结构中，O
2-
作立方密堆，Mg
2+
离子填入______。
单选题能进行交滑移的位错必然是______。
单选题测定某种晶体凝固时生长速度(vg)与液固相界面前端动态过冷度(△TK)的关系为vg正比于△TK2，则该晶体的属于______方式。
单选题铁碳合金中莱氏体在冷却过程中，该组织中的奥氏体______后称为变态莱氏体。
单选题从高分子的重复结构单元的对称性可知，最易结晶的是______。
单选题______ can be applied to thermoplastics only. A) Reaction injection molding B) Compression molding C) Blow molding D) Casting
单选题What are (or is) not the conditions on which the substitutional solid solution form? A) The solute atoms and the solvent atoms are of similar size. Specifically, the size oftheir atoms do not differ by more than 15/% B) The interstitial atoms are sufficiently small C) The electron configurations ofthe solute atoms and the solvent atoms are comparable D) The solute atoms and the solvent atoms have a common crystalline structure
单选题形成临界晶核时体积自由能的减少只能补偿表面能的______。 (A) 1/3(B) 2/3(C) 3/4
单选题Miller indices for crystal directions are expressed in ______ with no commas separating the numbers. A) ＜ ＞ B) ( ) C) [ ] D) { }
单选题晶体的对称轴中不存在______。
单选题根据整数定律，晶体结构中的坐标轴应该选取______的方向。
a．相互垂直 b．密排面 c．晶体中行列
单选题伯氏矢量为______的位错属于不可滑移位错。
单选题Among the following properties, temperatures have the greatest effect on ______. A) ductility B) impactstrength C) hardness D) strength