【正文】 The PM manufacturing process can b。 Economic advantage due to the low costs of process.material sciences39。life science39。materials sciences39。life sciences39。 and puts forward that nature reached a tremendous level of control and plexity with a limited number of chemical systems. In synthetic chemistry on the contrary, we can synthesize an unlimited number of monomers, building blocks and backbones but, until recently, with very limited control and plexity().Biology biotechnology Molecular nanotechnology Synthetic chemistry controlled plexity diversity Natural and synthetic chemistry In recent years progress has been made in two ways. The diversity in molecules synthesized by living organisms is increased by biotechnology. On the other hand a substantial jump has been made in synthetic chemistry towards more control and plexity, the socalled molecular nanotechnology or nanochemistry. J. M. Lehn drew an arrow in the diagram and said that progress would he made in that direction. This means that continuous mutual interaction between the two fieldsbiotechnology and molecular nanotechnologycould offer countless opportunities for new concepts.Time amp。 against 39。 pounds in a very nice picture in which he puts 39。 and 39。, JeanMarie Lehn pares39。 and materials for medical applications will certainly boom.Changes in science and technologyThe integration of biotechnology and nanotechnology can best be illustrated by a picture that I borrowed from JeanMarie Lehn. I have taken the liberty to adapt it slightly. In the last chapter of his book on 39。s, it is now in its fast growing phase. The next wave is the nanotechnology, only in itS embryonic phase at this moment. It is the bination or the integration of the latter two technology waves that will bring about the next change. It is hard to predict what the needs of this changing society will be. But, as far as materials are concerned, one can foresee that functional or smart materials for39。advanced materials39。 furthermore, they have very large molecular structures. These materials typically have low densities and may be extremely flexible. Composites: A number of posite materials have been engineered that consist of more than one material type. Fiberglass is a familiar example, in which glass fibers are embedded within a polymeric material. A posite is designed to display a bination of the best characteristics of each of the ponent materials. Fiberglass acquires strength from the glass and flexibility from the polymer. Many of the recent material developments have involved posite materials. Semiconductors: 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. The semiconductors have made possible the advent of integrated circuitry that has totally revolutionized the electronics and puter industries over the past two decades. Biomaterials: Biomaterials are employed in ponents implanted into the human body for replacement of diseased or damaged body parts. These materials must not produce toxic substances and must be patible with body tissue (. must not cause adverse biological reactions). All of the above materialsmetals, ceramics, polymers, posites and semiconductorsmay be used as biomaterials. For example, some of the biomaterials such as CF/C (carbon fibers/carbon) and CF/PS (polysulfone) are utilized in artificial hip replacements. Advanced MaterialsMaterials that are utilized in hightechnology (or hightech) 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。 that is, these electrons are not bound to particular atoms. Many properties of metals are directly attributable to these electrons. Metals are extremely good conductors of electricity and heat, and are not transparent to visible light。Exercises for discussion (1) What is materials science? What is materials engineering? (2) Why do we study materials science and engineering? (3) Give the important properties of solid materials. the following into Chinese materials science Stone Age naked eye Bronze age optical property integrated circuit mechanical strength thermal conductivity .Materials science is an interdisciplinary study that bines chemistry, physics, metallurgy, engineering and very recently life sciences. One aspect of materials science involves studying and designing materials to make them useful and reliable in the service of human kind. .Virtually all important properties of solid materials may be grouped into six different categories: mechanical, electrical, thermal, magnetic, optical, and deteriorative. .In addition to structure and properties, two other important ponents are involved in the science and engineering of materials, namely processing and performance. .The more familiar an engineer or scientist is with the various characteristics and structureproperty relationships, as well as processing techniques of materials, the more proficient and confident he or she will be to make judicious materials choices based on these criteria. the following into English 交叉學(xué)科 介電常數(shù) 固體材料 熱容 力學(xué)性質(zhì) 電磁輻射 材料加工 彈性系數(shù)（模數(shù)） Unit 2 Classification of MaterialsBasic Classifications and Engineering Materials Solid materials have been conveniently grouped into three basic classifications: metals, ceramics and polymers. This scheme is based primarily on chemical makeup and atomic structure, and most materials fall into one distinct grouping or an