已选分类
工学
单选题In which of the following fiber orientations, a maximum of fiber loading in composites can be achieved? A．unidirectional B．Bidirectional C．Multidirectional D．Random
单选题三种组元组成的试样在空气中用X射线衍射(XRD)分析其随温度变化而发生相变的情况，则最多可记录到______共存。
单选题在三元相图(ternary phase diagram)浓度三角形(equilateral triangle)中，凡成分(composition)位于______上的合金，它们含有另两个顶角所代表的两组元(component)含量相等。
单选题Which of the following polymers with little water-absorption resistance? A．high-density polyethylene B．nylon 6/6 C．fluorocarbons D．polyester
单选题Which feature is not associated with the compression molding technique? A．Producing parts with complex shapes and close tolerances B．High part-to-part uniformity and reproducibility C．Excellent control of fiber-to-resin ratios and low void content D．Producing parts with constant cross-section shape in a continuous way
单选题______ is used in curing system to speed up the sulfur vulcanizing. A．Lubricants, B．Plasticizer C．Hardener D．Accelerators
单选题The term for synthetic polymers used on soil, rock, and earth in construction. A．Aramide B．Earthscreens C．Geosynthetics D．Styrofoams
单选题任一合金的有序结构形成温度______无序结构形成温度。 (A) 低于 (B) 高于 (C) 可能低于或高于
单选题What is the CN for a bcc unit cell? A) 5 B) 8 C) 12 D) 24
单选题螺位错的位错线平行于滑移方向。
单选题The strength of a thermoplastic polymer such as polyethylene tends to increase after uniaxial deformation, because______. A．cross linking occurs during deformation B．oxidation occurs during deformation in air at room temperature C．polymer chains tend to align themselves with the chain axis oriented along the direction of deformation D．none of the above
单选题冷形变金属在回复阶段可消除______。
单选题菲克第一定律描述了稳态扩散的特征，即浓度不随______变化。 (A) 距离 (B) 时间 (C) 温度
单选题菲克第一定律(Fick's first law)描述了稳态扩散(steady-state diffusion)的特征，即浓度不随______变化。
单选题在MgO离子化合物中，最可能取代化合物中Mg2+的正离子(已知各正离子半径(nm)分别是：(Mg2+)0.066、(Ca2+)0.099、(Li+)0.066、(Fe2+)0.074)是______。
单选题______ involves transforming gases, liquids, and solid elements by chemical and physical means. where atoms and molecules are combined to form solid materials. A) Analysis B) Processing C) Synthesis D) Wroughting
单选题高分子的熔点随其晶片厚度的增加而______。
单选题影响淬火后残余奥氏体量的主要因素是( )。 A．钢材本身含碳量 B．奥氏体含碳量 C．加热时保温时间的长短 D．加热速度
单选题A field that involves the generation and application of knowledge relating to the composition, structure and processing of materials to their properties and use. A) Engineering Materials Technology B) Materials Engineering C) Materials Science D) Materials ScienceAnd Engineering
单选题不易产生交滑移的晶体结构为______。