同济大学机械工程专业英语翻译

同济大学机械工程专业英语翻译内容摘要：

glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from ：核心由高折射指数高纯光传输玻璃制成，中间层为低折射指数玻璃，是保护核心玻璃表面不被擦伤和完整性不被破坏的所谓覆层，外层是聚 合物护套，用于保护光导纤维不受损。 In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light. 为了使核心玻 璃有比覆层大的折射指数，在其中掺入微小的、可控数量的能减缓光速而不会吸收光线的杂质或搀杂剂。 Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle. 由于核心玻璃的折射指数比覆层大，只要在全内反射过程中光线照射核心 /覆层分界面的角度比临界角大，在核心玻璃中传送的光线将仍保留在核心玻璃中。 5 The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of 璃的高纯度一样，使光线几乎无强度损耗传递长距离成为可能。 Composites 复合材料 Composites are formed from two or more types of materials. Examples include polymer/ceramic and metal/ceramic posites. Composites are used because overall properties of the posites are superior to those of the individual。 例子有聚合物 /陶瓷和金属 /陶瓷复合材料。 之所以使用复合材料是因为其全面性能优于组成部分单独的性能。 For example: polymer/ceramic posites have a greater modulus than the polymer ponent, but aren’t as brittle as types of posites are: fiberreinforced posites and particlereinforced ：聚合物 /陶瓷复合材料具有比聚合物成分更大的模量，但又不像陶瓷那样易碎。 复合材料有两种：纤维加强型复合材料和微粒加强型复合材料。 Fiberreinforced Composites 纤维加强型复合材料 Reinforcing fibers can be made of metals, ceramics, glasses, or polymers that have been turned into graphite and known as carbon fibers. Fibers increase the modulus of the matrix material. 加强纤维可以是金属、陶瓷、玻璃或是已变成石墨的被称为碳纤维的聚合物。 纤维能加强基材的模量。 The strong covalent bonds along the fiber’s length giv e them a very high modulus in this direction because to break or extend the fiber the bonds must also be broken or 纤维长度有很强结合力的共价结合在这个方向上给予复合材料很高的模量，因为要损坏或拉伸纤维就必须破坏或移除这种结合。 Fibers are difficult to process into posites, making fiberreinforced posites relatively ，这使得制造纤维加强型复合材料相对昂贵。 Fiberreinforced posites are used in some of the most advanced, and therefore most expensive sports equipment, such as a timetrial racing bicycle frame which consists of carbon fibers in a thermoset polymer matrix. 纤维加强型复合材料用于某些最先进也是最昂贵的运动设备，例如计时赛竞赛用自行车骨架就是用含碳纤维的热固塑料基材制成的。 Body parts of race cars and some automobiles are posites made of glass fibers (or fiberglass) in a thermoset matrix. 竞赛用汽车和某些机动车的车体部件是由含玻璃纤维 (或玻璃丝 )的热固塑料基材制成的。 Fibers have a very high modulus along their axis, but have a low modulus perpendicular to their axis. Fiber posite manufacturers often rotate layers of fibers to avoid directional variations in the ，但垂直于其轴向的模量却较低。 纤维复合材料的制造者往往旋转纤维层以防模量产生方向变 化。 Particlereinforced posites 微粒加强型复合材料 Particles used for reinforcing include ceramics and glasses such as small mineral particles, metal particles such as aluminum, and amorphous materials, including polymers and carbon 类的矿物微粒、铝之类的金属微粒以及包括聚合物和碳黑的非结晶质微粒。 6 Particles are used to increase the modulus of the matrix, to decrease the permeability of the matrix, to decrease the ductility of the matrix. An example of particlereinforced posites is an automobile tire which has carbon black particles in a matrix of polyisobutylene elastomeric 、减少基材的渗透性和延展性。 微粒加强型复合材料的一个例子是机动车胎，它就是在聚异丁烯人造橡胶聚合物基材中加入了碳黑微粒。 Polymers 聚合材料 A polymer has a repeating structure, usually based on a carbon backbone. The repeating structure results in large chainlike molecules. Polymers are useful because they are lightweight, corrosion resistant, easy to process at low temperatures and generally。 这种重复结构产生链状大分子。 由于重量轻、耐腐蚀、容易在较低温度下加工并且通常较便宜，聚合物是很有用的。 Some important characteristics of polymers include their size (or molecular weight), softening and melting points, crystallinity, and structure. The mechanical properties of polymers generally include low strength and high toughness. Their strength is often improved using reinforced posite ，包括尺寸 (或分子量 )、软化及熔化点、结晶度和结构。 聚合材料的机械性能一般表现为低强度和高韧性。 它们的强度通常可采用加强复合结构来改善。 Important Characteristics of Polymers 聚合材料的重要特性 Size. Single polymer molecules typically have m。