材料科学与工程专业英语Unit2ClaificationofMaterials译文_草业科学专业英语
材料科学与工程专业英语Unit2ClaificationofMaterials译文由刀豆文库小编整理，希望给你工作、学习、生活带来方便，猜你可能喜欢“草业科学专业英语”。
Claification of Materials（材料分类）
Solid materials have been conveniently grouped into three basic claifications: metals, ceramics, and polymers.This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or another, although there are some intermediates.In addition, there are three other groups of important engineering materials—composites, semiconductors, and biomaterials.译文：固体材料被便利的分为三个基本的类型：金属，陶瓷和聚合物。这个分类是首先基于化学组成和原子结构来分的，大多数材料落在明显的一个类别里面，尽管有许多中间品。除此之外，有三类其他重要的工程材料－复合材料，半导体材料和生物材料。
Composites consist of combinations of two or more different materials, whereas semiconductors are utilized because of their unusual electrical characteristics;biomaterials are implanted into the human body.A brief explanation of the material types and representative characteristics is offered next.译文：复合材料由两种或者两种以上不同的材料组成，然而半导体由于它们非同寻常的电学性质而得到使用；生物材料被移植进入人类的身体中。关于材料类型和他们特殊的特征的一个简单的解释将在后面给出。Metallic materials are normally combinations of metallic elements.They have large numbers of nonlocalized electrons;that is, these electrons are not bound to particular atoms.Many properties of metals are directly able to these electrons.译文：金属材料通常由金属元素组成。它们有大量无规则运动的电子。也就是说，这些电子不是被约束于某个特定的原子。金属的许多性质直接归属这些不规则运动的电子。
Metals are extremely good conductors of electricity and heat and are not transparent to visible light;a polished metal surface has a lustrous appearance.Furthermore, metals are quite strong, yet deformable, which accounts for their extensive use in structural applications.译文：金属是十分好的电和热的导体，它们对可见光不透明；一个抛光的金属表面有光辉的外表。除此之外，金属是十分硬的，也是可变形的，这个性质解释了它们广泛使用在结构方面的应用。
Ceramics are compounds between metallic and nonmetallic elements;they are most frequently oxides, nitrides, and carbides.The wide range of materials that falls within this claification includes ceramics that are composed of clay minerals, cement, and gla.译文：陶瓷是介于金属和非金属元素之间的化合物；它们通常是氧化物，氮化物和碳化物。落在这个分类种类中的宽的材料范围包括陶瓷，它们由粘土矿物，水泥和玻璃组成。
These materials are typically insulative to the paage of electricity and heat, and are more resistant to high temperatures and harsh environments than metals and polymers.With regard to mechanical behavior, ceramics are hard but very brittle.译文：这些材料是典型的电和热的绝缘体，并且它们比金属和聚合物更加耐高温和耐苛刻的环境。至于机械性能，陶瓷是硬的但是却很脆。
Polymers include the familiar plastic and rubber materials.Many of them are organic compounds that are chemically based on carbon, hydrogen, and other nonmetallic elements;furthermore, they have very large molecular structures.These materials typically have low densities and may be extremely flexible.译文：聚合物包括常见的塑料和橡胶材料。它们中的大多数是有机化合物，这些化合物是以化学的方法把碳、氢和其他非金属元素组合而成。因此，它们有非常大的分子结构。这些材料通常有低的密度并且可能十分柔软。
A number of composite materials have been engineered that consist of more than one material type.Fibergla is a familiar example, in which gla fibers are embedded within a polymeric material.译文：许多复合材料被作用工程使用，它们由至少一种类型的材料组成。玻璃丝是一个熟悉的例子，玻璃纤维被埋入聚合物材料中。
A composite is designed to display a combination of the best characteristics of each of the component materials.Fibergla acquires strength from the gla and flexibility from the polymer.Many of the recent material developments have involved composite materials.译文：为了联合显示每一种组分材料最好的特性，一种复合材料被设计出来。玻璃丝从玻璃中获得强度并且从聚合物中获得柔软性。最近发展中的绝大多数材料包含了复合材料。
Semiconductors have electrical properties that are intermediate between the electrical conductors and insulators.Furthermore, the electrical characteristics of these materials are extremely sensitive to the presence of minute concentrations of impurity atoms, which concentrations may be controlled over very small spatial regions.译文：半导体有电的性质，它们是介于电导体和绝缘体之间的中间物。除此之外，这些材料的电学性质对微量杂质原子的存在十分敏感，杂质原子浓度可能只是在一个十分小的区域内可以控制。
Biomaterials are employed in components implanted into the human body for replacement of diseased or damaged body parts.These materials must not produce toxic substances and must be compatible with body tiues(i.e., must not cause adverse biological reactions).译文：生物材料被应用于移植进入人类身体以取代病变的或者损坏的身体部件。这些材料不能产生有毒物质而且必须同人身体器官要相容（比如，不能导致相反的生物反应）。
Materials that are utilized in high-technology(or high-tech)applications are sometimes termed advanced materials.By high technology we mean a device or product that operates or functions using relatively intricate and sophisticated principles;examples include electronic equipment , computers, fiberoptic systems, spacecraft, aircraft, and military rocketry.译文：用在高科技中的材料有时被称作先进材料。借助于高科技，我们预定一个装置或者产品，这些产品用相对复杂和熟练的原理运转或者起作用；这些例子包括电子设备，计算机，光纤系统，宇宙飞船，航天飞机和军事火箭。
In spite of the tremendous progre that has been made in the discipline of materials science and engineering within the past few years, there still remain technological challenges, including the development of even more sophisticated and specialized materials, as well as consideration of the environmental impact of materials production.Some comment is appropriate relative to these iues so as to round out this perspective.译文：在过去几年内，不论材料科学与工程的规律取得了巨大的进步，仍然有一些技术挑战，包括开发更加熟练的专业化的材料，并且考虑材料生产对环境导致的影响。针对这个问题，一些评论是十分相关的。
Nuclear energy holds some promise, but the solutions to the many problems that remain will necearily involve materials, from fuels to containment structures to facilities for the disposal of radioactive waste.译文：核能还保持着一些承诺，但是解决许多仍然存在的问题，将有必要把材料包括在里，从燃料到保护结构以便方便处置这些放射性废料。
Significant quantities of energy are involved in transportation.Reducing the weight of transportation vehicles(automobiles, aircraft, trains, etc.), as well as increasing engine operating temperatures, will enhance fuel efficiency.New high strength, low-density structural materials remain to be developed, as well as materials that have higher-temperature capabilities, for use in engine components.译文：相当数量的能源用在交通上。减少交通工具（汽车，飞机，火车等）的重量，和提高引擎操作温度，将提高燃料的使用效率。新的高强，低密度结构材料仍在发展，用作引擎部位能耐高温材料也在发展中。
Furthermore, there is a recognized need to find new,economical sources of energy, and to use the present resources more efficiently.Materials will undoubtedly play a significant role in these developments.译文：除此之外，寻找新的、经济的能源资源，并且更加有效的使用目前现存的资源是公认为必须的。材料将毫无疑问的在这些发展过程中扮演重要的角色。
For example, the direct conversion of solar into electrical energy has been demonstrated.Solar cells employ some rather complex and expensive materials.To ensure a viable technology, materials that are highly efficient in this conversion proce yet le costly must be developed.译文：比如，太阳能直接转化为电能已经被证实了。太阳能电池使用相当复杂并且昂贵的材料。为了保证技术的可行，在这个转化过程中的高效但不贵的材料必须被发展。
Furthermore, environmental quality depends on our ability to control air and water pollution.Pollution control techniques employ various materials.In addition, materials proceing and refinement methods need to be improved so that they produce le environmental degradation, that is, le pollution and le despoilage of the landscape from the mining of raw materials.译文：除此之外，环境质量取决于我们控制大气和水污染的能力。污染控制技术使用了各种材料。再者，材料加工和精制的方法需要改善以便它们产生很少的环境退化，也就是说，在生材料加工过程中，带来更少的污染和更少的对自然环境的破坏。
Also, in some materials manufacturing procees, toxic substances are produced, and the ecological impact of their disposal must be considered.Many materials that we use are derived from resources that are nonrenewable, that is, not capable of being regenerated.These include polymers, for which the prime raw material is oil, and some metals.These nonrenewable resources are gradually becoming depleted.译文：也，在一些材料生产过程中，有毒物质产生了，并且它们的处置对生态产生的影响必须加以考虑。
我们使用的许多材料来源于不可再生的资源，不可再生也就是说不能再次生成的。这些材料包括聚合物，最初的原生材料是油和一些金属。这些不可再生的资源逐渐变得枯竭
