（4） 表示递进：进而，并且。
He did it，and did it well. 他做了，并且做得很好。 More and more companies are installing automatic process controls as means of insuring product uniformity，and thus，quality． 越来越多的公司正在建立自动过程控制系统，作 为保证产品稳定，进而保证产品质量的手段。
第二部分 专业文章阅读与翻译
Lesson 1 Size of atoms and ions
Word study
1．ium：词尾 元素周期表中金属元素的词尾；有机阳离 子词尾，鎓(代表包含氢或一个或多个有机基与 一个中心原子配位的络阳离子) 。 例词：lithium 锂 oxonium 氧鎓 beryllium 铍 sulfonium 锍，锍鎓 sodium 钠 nitronium 硝鎓 ammonium 铵
1 氢 H Hydrogen 3 锂 Li Lithium 5 硼 B Boron 7 氮 N Nitrogen 9 氟 F Fluorine 11 钠 Na Sodium 13 铝 Al Aluminum 15 磷 P Phosphorus 17 氯 Cl Chlorine 19 钾 K Potassium
2 氦 He Helium 4 铍 Be Berillium 6 碳 C Carbon 8 氧 O Oxygen 10 氖 Ne Neon 12 镁 Mg Magnesium 14 硅 Si Silicon 16 硫 S Sulfur 18 氩 Ar Argon 20 钙 Ca Calcium
21 钪 Sc Scandium 22 钛 Ti Titanium 23 钒 V Vanadium 24 铬 Cr Chromium 25 锰 Mn manganese 26 铁 Fe Iron 27 钴 Co Cobalt Gold, silver, mercury, bromine, iodine, Platinum等等
此外，原子核的正电荷与轨道电子数目的比率增加了， 这样就使有效核电荷数增加，从而将电子拉向原子核。因 此，正离子的半径小于相应的原子半径，而且失去电子数 越多（即离子带有更多的电荷），离子半径就越小。


atomic radius Na 0.157 nm ionic radius Na+ 0.098 nm

（5） 表示时序：于是，然后。
She washed the beakers and dried them。 她把烧杯洗净，然后烘干。 when the solution in the tank has reached the desired temperature，it is discharged，a new batch of cool solution is added，and the process is repeated. 当罐内溶液达到所需要的温度时，就卸料，装入新 的一批冷溶液，于是过程再次重复。
(3) 表示转折：而，但是，然而。

An acid was once defined as a substance that would form hydrogen ions(H+) in water solution and a base as one that would form hydroxide ions(OH-) in the same. 人们曾把酸定义为在水溶液中能产生氢离子的物 质，而碱则是在同样的溶液中能产生氢氧离子的 物质。
2．and
and给人先入为主的联想是“和”，其实， and有多种含义，见下列例句。在科技英语 翻译中，应予以注意。
(1) 表示并列：和，与，跟，以及，并且。
(2) 表示结果：因此，所以，而，则。


The principles of both absorption and desorption are basically the same，and we may study both operations at the same time. 吸收和解吸这两个过程的原理基本相同，因此可 以同时研究这种操作。 Beginning from butane it is possible for the hydrocarbons to have one or more branch chains and isomerism results. 从丁烷开始这种烃就可能含有一个或更多个支链， 这就产生了异构现象。
Abstract：
In this thesis, the batch cooling crystallization process of fine granular vitamin C was investigated and analyzed systematically, based on the former research of the crystal structure and the thermodynamics of vitamin C. The mechanism of the crystallization process was explored and the crystallization kinetics of fine granular vitamin C was determined experimentally. We also develop a new crystallization technology of fine granular vitamin C and finally establish a mathematic model of this process. The present work settled some experimental and theoretical foundations for the design and scale-up of the industrial crystallization process of fine granular vitamin C.
atomic radius Fe 0.117 nm ionic radius Fe2+ 0.076 nm ionic radius Fe3+ 0.064 nm

when a negative ion is formed, one or more electrons are added to an atom，the effective nuclear charge is reduced and hence the electron cloud expands. Negative ions are bigger than the corresponding atom.


The consequence is a severance of carbon linkage at the point of the original double bond with the formation of two oxidation fragments, and ketones, acids and aldehydes result． 其结果是在最初双键处碳键断裂，形成两个氧化 碎片，结果形成酮、酸和醛。 when concentrated nitric acid is dissolved in concentrated sulphuric acid it ionizes and gives a nitronium ion． 当浓硝酸溶于浓硫酸中时，就发生离子化而产生 硝鎓离子。

（6） 表示选择：或，或者。

This will include property taxable for state and county purposes.
这将包括州或县支配的应征税的财产。
（7）表示条件：要是……就。

Give him some money and he will help you．
要是你给他钱，他就给你帮忙。
（8）表示目的：为了。也可不译。

Let us join and proceed together.
让我们联合起来共同前进。
Lesson 1 Size of atoms and ions

The size of atoms decreases from left to right across a period in the periodic table. For example, on moving from lithium to beryllium, the number of charges on the nucleus is increased by one, so that all the orbital electrons are pulled in closer to the nucleus.
在周期表中，沿着周期表从左到右原子的半径 逐渐减小。例如，从锂到铍，核电荷数增加了一 个，因此，轨道电子就被吸引得更靠近原子核。
In a given period, the alkali metal is the largest atom and the halogen the smallest. When a row of ten transition elements or fourteen inner transition elements occurs in a horizontal period, the contraction in size is even more marked.
原子失去一个或多个电子形成正离子。通常， 由于外层电子的失去，内层电子不能跑到空间上 更远的地方，阳离子比金属原子要小些。
In addition, the ratio of positive charges on the nucleus to the number of orbital electrons is increased. Thus the effective nuclear charge is increased and the electrons are pulled in. A positive ion is therefore smaller than the corresponding atom and the more electrons removed (that is, the greater the charge on the ion), the smaller it becomes.