Unit2
Materials Science and Engineering
Materials are properly more deep-seated in our culture than most of us realize.
材料可能比我们大部分人所意识到的更加深入地存在于我们的文化当中。Transportation,housing,clothing,communication,recreation and food production－virtually every segment of our lives is influenced to one degree or another by materials.运输、住房、衣饰、通讯、娱乐，还有食品生产——实际上我们日常生活的每个部分都或多或少地受到材料的影响。
Historically,the development and advancement of societies have been intimately tied to the members’abilities to produce and manipulate materials to fill their needs.从历史上看，社会的发展和进步已经与社会成员生产和利用材料来满足自身需求的能力紧密地联系在一起。
In fact,early civilizations have been designated by the level of their materials development.事实上，早期文明是以当时材料的发展水平来命名的。（也就是石器时代，青铜器时代）
The earliest humans has access to only a very limited number of materials, those that occur naturally stone,wood,clay,skins,and so on.
最早的人类只能利用非常有限数量的材料，象那些自然界的石头，木头，黏土和毛皮等等。With time they discovered techniques for producing materials that had properties superior to those of the natural ones:these new materials included pottery and various metals.随着时间的推延，人类发现了性能优于自然材料的制造新材料的技术：这些新材料包括陶器，各种金属。
Furthermore,it was discovered that the properties of a material could be altered by heat treatments and by the addition of other substances.而且，人类发现通过对这些材料进行热处理和添加新的元素可以改变材料的性能。
At this point,materials utilization was totally a selection process,that is,deciding from a given,rather limited set of materials the one that was best suited for an application by virtue of its characteristic.从这一点来说，材料利用完全地是一个选择过程，也就是说，在给定的相当有些限的一批材料中根据材料的特性,为某种具体的应用选择最适合的材料。
It was not until relatively recent times that scientists came to understand
直到前不久的一段时间里，科学家们才开始了解材料的
the relationships between the structural elements of materials and their properties.
组成元素与其性质之间的关系。
This knowledge,acquired in the past60years or so,has
这个在过去60年左右的时间里得到的结论已经
empowered them to fashion,to a large degree,the characteristics of materials.
促使科学家们更广泛地运用材料的这些特性。
Thus,tens of thousands of different materials have evolved with rather,
因此，数以万计的具有专门特性的不同材料应运而生。
specialized characteristics that meet the needs of our modern and complex society.它们满足了现代复杂社会的需要。
The development of many technologies that make our existence so comfortable 许多使我们的生活如此舒适的技术的发展都
has been intimately associated with the accessibility of suitable materials.
与（人类）能够获得合适的材料密切相关。
Advancement in the understanding of a material type is often the forerunner to
往往对一种材料类型的理解的进步会成为某一技术
the stepwise progression of a technology.
发展历程的第一步。
Materials Science and Engineering
Materials science is an interdisciplinary study that combines chemistry,physics, metallurgy,engineering and very recently life sciences.材料科学是一门结合了化学，物理，冶金，工程以及最近结合的生命科学的跨专业研究科学。One aspect of materials science involves studying and designing materials to make them useful and reliable in the service of human-kind.材料科学研究的一个方面是研究开发服务于人类使用的可靠的材料。
It strives for basic understanding of how structures and processes on the atomic scale result in the properties and functions familiar at the engineering level.它力争对原子层次上物质的结构及加工对我们熟悉的工程上材料的性能和功能的影响有一个基本的认识。Materials scientists are interested in physical and chemical phenomena acting across large magnitudes of space and time scales.材料科学家们感兴趣的是大跨度空间与时间上发生的物理化学现象。In this regard it differs from physics or chemistry where the emphasis is more on explaining the properties of pure substances.在这一点，它不同于把重点更多的放在解释纯粹物质特征现象的物理和化学专业。In materials science there is also an emphasis on developing and using knowledge to understand how the properties of materials can be controllably designed by the varying the compositions,structures,and the way in which the bulk and surfaces phase materials are processed.材料科学还有一个重点是发展使用知识来了解如何通过更改材料的成分，结构和大量表面相材料的处理方法来控制设计材料的性能。
materials engineering is,on the basis of those structure properties correlations, designing or engineering the structure of a material to produce a predetermined set of properties.材料工程是在（材料）结构和性能相互联系的基础上，设计策划一种材料的结构来实现一系列预知的性能。In other words,material engineering mainly deals with the use of materials in design and how materials are manufactured.换句话讲，材料工程主要涉及材料设计方面的用途和生产方案的问题。
“structure”is a nebulous term that deserves some explanation.“结构”是一个应当予以解释的模糊概念。In brief,the structure of a material usually relates to the arrangement of its internal components.简言之，一种材料的结构通常与其内部成分的排列有关。Subatomic structure involves electrons within the individual atoms and interactions with their nuclei.亚原子结构包括单个原子内部的电子以及它们和原子核之间的相互作用。On anatomic level,structure encompasses the organization of atoms or molecules relative to another.The next large structural realm, which contains large groups of atoms that are normally agglomerated together,is termed“microscopic”meaning that which is subject to direct observation using some type of microscope.在原子水平上，结构包括与另外的原子或分子相对的原子或分子的组织，更高层次的结构领域包含我们称作“微观的”结构，该结构是凝聚成一
