表面工程形成一门独立的学科虽然只是近20年的事，但其发展之快、涉及范围之广、对人们生产生活影响之大是当初大多数人所始料未及的。表面工程的概念由英格兰伯明翰大学教授汤·贝尔（TomBell）于1983年首次提出，现已发展成为跨学科的边缘性、综合性、复合型学科。表面工程是将材料表面与基体一起作为一个系统进行设计，利用表面改性技术、薄膜技术和涂镀层技术，使材料表面获得材料本身没有而又希望具有的性能的系统工程。可以说，在材料表面上所发生的各种技术都是表面工程的一部分

一、 学习和掌握投入产出分析的基本原理 二、学习和掌握在环境决策中进行投入产出分析的方法和步骤

The C—X bond of alkyl halides is polarized. The carbon atom bears a partial positive charge, The halogen atom a partial negative charge

First order overall (一级反应) The reaction is a unimolecular nucleophilic substitution（单分子亲核取代反应）

There is a group of compounds in which carbon forms only two bonds. These neutral divalent carbon compounds are called carbenes. Most carbenes are highly unstable compounds that are capable of only fleeting existence. Soon after carbenes are formed they usually react with another molecule

How are molecular structures determined? One way is though the use of spectroscopic methods. Spectroscopy is the study of the interaction of energy with matter. When energy is applied to matter it can be absorbed, emitted, cause a chemical change, or be transmitted

A mass spectrometer produces a spectrum of masses based on the structure of a molecule. It is a spectrum or plot of the distribution of ion masses corresponding to the formula weight of a molecule, fragments derived from the molecule, or both

These spectra are often called carbon magnetic resonance (CMR) spectra or 13C NMR spectra. In some important ways 13C spectra are usually les complex and easier to interpret than proton (1H) NMR spectra

In the addition of HX to an unsymmetrically substituted alkene, the hydrogen atom adds to the carbon atom of the double bond that already has the greater number of hydrogen atoms and that the X group adds to the carbon having more alkyl substituents. Markovnikov’s rule can be restated by saying that, in the addition of HX to an alkene, the more stable carbocation intermediate is formed

1. The experimental conditions — temperature and acid concentration — that are required to being about dehydration are closely related to the structure of the individual alcohol. The relative ease with which alcohols undergo dehydration is in the following order: