已选分类
工学材料科学与工程
单选题在定向凝固中，希望获得最大程度的提纯，有效分配系数应该______。
单选题对Fe-Cr-C三元系合金进行渗C的反应扩散，则该合金中不能出现______。
单选题Anaerobic adhesives set up into hard, strong adhesives when ______. A．The two parts of resin and catalyst are mixed B．Squeezed into thin joints which block the oxygen C．The solvents evaporate or penetrate porous adherends D．The heat source is removed
单选题铸铁(cast iron)与碳钢(carbon steel)的区别在于有无______。
单选题Which term describes well-defined methods for solving specific problems, such as those used to develop an approach to materials selection? A) JIT B) Design C) Algorithm D) CIM
单选题合金在凝固时产生成分过冷的条件是______。(其中TL是成分为CL的合金开始凝固温度)
单选题立方晶体中(110)和(211)面同属于______晶带。
单选题Trade name for aramid fiber, which is used for bulletproof vests and advanced composites for aerospace applications. A) E-glass B) Kevlar C) Borsic D) Graphite
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______。