大学化工专业英语Lesson-3

第三章 单
词
• 单词是构成句子的基本要素之一，因此， 单词的翻译直接关系到句子3.1.1 可数名词复数前没有数量词时，一般要 把复数含义翻译出来，即在名词前加译“一 些，这些，许多”等词，例如： • The teacher may be asked questions. 可以向老师提一些问题。 • Our first electronic computers were made in 1958. 我国首批电子计算机是1958年制成的。 • we are students of Henan University. 我们是河南大学的学生。
3.1.3 a(an)+名词（可数，不可数）单数表示“一类” 时，不能译出不定冠词“a(an)”
Salts may also be found by the replacement of hydrogen from an acid with a metal. 盐也能通过用金属置换酸中的氢而获得。
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，而碱则是在同样溶液中会产生氢氧根离子 的物质。
• 注：对于billion及其以上的数字，英语和美语的 译法不同，翻译时应视此句出于何种国家的刊物 而定。 英语 美语 million 106 106 billion 1012（万亿） 109（十亿） trillion 1018（百万兆） 1012（兆,百万个百万） quadrillion 1024（百万的四次方）1015（一千的五次方） quintillion 1030（百万的五次方） 1018（百万之三次方）

deci-分 decigram 分克(1/10克)；decimeter 分米
centi- 厘 centimeter 厘米；centigram厘克
nano- 纳
nanometer纳米；
nanosecond十亿分之一秒（10-9秒）
milli-毫 millimeter毫米；millilitre毫升； milligram毫克
需要注意的是，表中物质的数目词头除前四个另 有名称外，其它均为表上的数目词头。
数字 拉丁或希 烷烃-ane 烷基-yl 烯烃-ene 腊前缀 alkane alkyl Alkene
炔烃-yne 醇-ol alkyne alcohol
醛-al aldehyde
one mono- methane methyl
4.名词+动名词（n.+v.ing）
paper-making 造纸 ship-building 造船 Machine-shaping ？
5.其他构成方式
By-product 副产品（介词+名词） Make-up 化妆品（动词+副词） Out-of-door 户外 （副词+介词+名词） Pick-me-up 兴奋剂 （动词+代词+副词）
2.形容词+名词（adj.+n.）
其意义关系是前者修饰后者 Blueprint periodic table mixed-powder atomic weight
3.动名词+名词（v.ing+n.）
动名词所表示的是与被修饰词有关的 动作，而名词所表示的是可用的场所或物 品。 Launching site 发射场 flying-suit 飞行衣 navigating instrument ？

前几课翻译链接：/s/1o6qiyuQLesson 10 ThermodynamicsThermodynamics is the physics of energy, heat, work, entropy and the spontaneity of processes. Thermodynamics is closely related to statistical mechanics from which many thermodynamic relationships can be derived.热力学是物理能量，热，工作过程，熵和自发性。

热力学是密切相关的统计力学，热力学关系可以推导出。

While dealing with processes in which systems exchange matter or energy, classical thermodynamics is not concerned with the rate at which such processes take place, termed kinetics. For this reason, the use of the term “thermodynamics”usually refers to equilibrium thermodynamics. In this connection, a central concept in thermodynamics is that of quasistatic processes, which are idealized, “infinitely slow”processes. Time-dependent thermodynamic processes are studied by non-equilibrium thermodynamics.在处理中，系统交换物质或能量的过程，经典热力学不关心这些过程发生的速率，称为动力学。

元素是单纯的物质，不能通过一般的化学变化分解成为更简单的物质。目前已知有109个元素。一些你熟悉的常见元素是碳、氧、铝、铁、氮和金。元素是组成物质的基本单元，就象0到9的数字是组成数的基本单元一样。就我们所知，已经在地球上发现的元素也是组成整个宇宙的元素。
About 85% of (85 percent of) the elements can be found in nature , usually combined with other elements in minerals and vegetable matter or in substances like water and carbon dioxide. Copper, silver, gold, and about 20 other elements can be found in highly pure forms. Sixteen elements are not found in nature; they
Lesson one Elements and Compounds
元素与化合物
Elements are pure substances that can not be decomposed(分解) into simpler substances by ordinary chemical changes. At present there are 109 known elements. Some common elements that are familiar to you are carbon, oxygen, aluminum, iron, copper, nitrogen, and gold. The elements are the building blocks of matter just as the numerals 0 through 9 are the building blocks for numbers. To the best of1 our knowledge, the elements that have been found on the earth also comprise(包含) the entire universe.

H2SO3 sulfurous acid
HNO3 nitric acid HNO2 nitrous acid HPO3 metaphosphoric acid 偏磷酸
3. Nomenclature of bases （碱的命名）
元素名称 + hydroxide
NaOH sodium hydroxide KOH potassium hydroxide
H3O＋ hydronium ion
1.2. Names of Anions（阴离子的命名）
1.2.1 monatomic anions (单原子阴离子)： 以-ide结尾
H－ hydride ion (H: hydrogen)
O2 oxide ion (O: oxygen)
N3 nitride ion (N: nitrogen)
旧的方法: 用bi-前缀来表示：HSO4－ bisulfate ion
HCO3 bicarbonate ion
2. Nomenclature of Acids （酸的命名）
2.1 无氧酸 (即阴离子以-ide结尾的酸)
前缀hydro- + 元素名称 + 后缀-ic acid
HCl hydrochloric acid
•Silicon 铝•G[ deʒrəm:'maeniniuiəmm (]锗)
• • •
Potassium • Rubidium (铷) Cesium (铯) •
Strontium (锶)
[ 'strɔntiəm ]
Barium (钡)
•Gallium (镓) •Tin 锡 •Indium (铟) •Lead 铅 •Thallium (铊)

Here is an important list of rules to follow:
1. The parent chain is numbered so that the multiple bonds have the lowest numbers (double and triple bonds have priority over alkyl and halo substituents).
3. When both double and triple bonds are present, the -en suffix follows the parent chain directly and the -yne suffix follows the -en suffix (notice that the e is left off, -en instead of -ene). The location of the double bond(s) is(are) indicated before the parent name as before, and the location of the triple bond(s) is(are) indicated between the -en and -yne suffixes. See below for examples.
CH3 CH H2C CH2
methylcyclopropane
CH3
CH3
CH3 CH CH2 CH2 CH CH2 CH CH2 CH3
CH CH3
CH2 CH3
5-sec-butyl-2,7-dimethylnonane
CH3 CH2 CH CH CH2 CH3 CH3 CH2 CH3

化工专业英语翻译（全21单元）化学工程与工艺专业英语课文翻译Unit 1 Chemical Industry化学工业...................................................................................... - 1 -Unit 2 Research and Development研究和开发................................................................... - 3 -Unit 3 Typical Activities of Chemical Engineers化学工程师的例行工作............................ - 5 -Unit 4 Sources of Chemicals化学资源................................................................................. - 7 -Unit 5 Basic Chemicals基本化学品...................................................................................... - 9 -Unit 6 Chlor-Alkali and Related Processes氯碱及其相关过程.......................................... - 10 -Unit 7 Ammonia, Nitric Acid and Urea氯、硝酸和尿素................................................... - 12 -Unit 8 Petroleum Processing石油加工 .............................................................................. - 15 -Unit 9 Polymers 聚合物 ................................................................................................... - 16 -Unit 10 What Is Chemical Engineering?什么是化学工程学 .............................................. - 18 -Unit 11 Chemical and Process Thermodynamics化工热力学 ........................................... - 21 -Unit 12 What do we mean by transport phenomena ?如何定义传递现象...................... - 23 -Unit 13 Unit Operations in Chemical Engineering化学工程中的单元操作...................... - 24 -Unit14 Distillation蒸馏....................................................................................................... - 26 -Unit 15 Solvent Extraction, Leaching and Adsorption溶剂萃取，浸取和吸附................ - 28 -Unit 16 Evaporation, Crystallization and Drying 蒸发、结晶和干燥................................. - 31 -Unit 17 Chemical Reaction Engineering化学反应工程 ..................................................... - 33 -Unit18 Chemical Engineering Modeling化工建模 ............................................................. - 36 -Unit 19 Introduction to Process Design过程设计简介...................................................... - 37 -Unit 20 Material Science and Chemical Engineer材料科学和化学工程........................... - 39 -Unit 21 Chemical Industry and Environment化学工业与环境 ......................................... - 42 - Unit 1 Chemical Industry化学工业1．化学工业的起源尽管化学品的使用可以追溯到古代文明时代，我们所谓的现代化学工业的发展却是非常近代（才开始的）。

第二部分化学化工专业基础知识第二节Nomenclature of Organic Chemistry一．The Need for Classification of Organic Compounds The field of organic chemistry is vast, for it includes not only the composition of all living organisms but also of a great many other materials that we use daily.It is physically impossible for one to study the properties of each of the hundreds of thousands of known organic compounds. Hence organic compounds with similar structural features are grouped into series or classes. Some of the classes of organic compounds are hydrocarbons, alcohols,aldehydes,ketones,ethers, carboxylic acids, esters, carbohydrates, and proteins. Each of these classes of compounds is identified by certain characteristic structural features.⏹hydrocarbons, 烃类，碳氢化合物⏹alcohols, 醇类⏹aldehydes, 醛类⏹ketones, 酮类⏹ethers, 醚类⏹carboxylic acids, 羧酸⏹esters, 酯类⏹carbohydrates,糖类，碳水化合物1. HydrocarbonsHydrocarbons are composed entirely of carbon and hydrogen atoms bonded to each other by covalent bonds.Several series of hydrocarbons are known. These include the alkanes, alkenes, alkynes, and aromatic hydrocarbons.alkanes, [‘ælkeinz]烷烃alkenes, [‘ælki:nz]烯烃alkynes, [‘ælkainz]炔烃aromatic hydrocarbons，芳香烃Classification of Hydrocarbons：1.1 Aliphatic compounds (脂肪烃)Rule A-1. Saturated Unbranched-chain Compounds and Univalent RadicalsRule A-2. Saturated Branched-chain Compounds and Univalent RadicalsRule A-3. Unsaturated Compounds and Univalent Radicals1.1.1 Alkanes (C n H2n+2)1.1.1.1 Straight-Chain Alkanes一．“元素”和“单质”的英文意思都是―element‖，有时为了区别，在强调―单质‖时可用―free element‖。

《化学工程与工艺专业英语》课文翻译-Unit3 Typical Activities of ChemicalEngineers本文将介绍化学工程师在日常工作中的一些典型活动。

化学工程师旨在将化学与工程学的原理应用于产业中，解决生产过程中的各种问题并开发新产品。

化学工程师随着技术的发展和市场的变化而发展和变化。

但以下是其典型活动：第一，设计新的工艺流程。

化学工程师需要了解化学反应原理、物质转化和热量传递方程式，以及流体力学和系统分析等方面的知识，创造出新的工艺流程。

在此基础上，他们可以设计出化学反应器、分离装置和加工设备等。

而在设计之前，化学工程师会根据产品需求和工厂生产线等因素，制定经济可行性和技术可行性分析，制定整个流程方案。

第二，工厂的设计和规划。

这些安装要求使用化学工程师的技能和知识。

工程师需要考虑由工厂所需的供电、供水和废物处理等各个方面。

他们需要选择合适的材料和设备，也需要在设计中采用节能和环境保护技术。

他们也必须为紧密的安全要求和法律法规做好准备。

第三，处理产品的生产和质量控制。

生产线上的任何错误都有可能导致生产过程劣化和生产失败。

化学工程师通过控制生产过程的不同参数和调整生产中的机器设备、材料流程和成品质量保障等，确保产品的质量和产品的性能。

如果有任何生产上的问题，他们都需要快速响应，并及时寻找解决方法。

第四，进行研究和开发。

在工业生产中，研究和开发是至关重要的。

化学工程师必须熟悉当前和未来的技术发展。

他们需要收集和分析大量的数据和材料，以探索和开发新的技术和产品，面对多种工艺流程，为生产线输入新的元素。

第五，进行销售和市场分析。

销售和市场分析也是化学工程师需要了解的另一个方面。

他们需要熟悉市场需求和市场潜力。

工程师必须在市场竞争激烈的环境中发挥创新、争取同行的业务和合作伙伴，为他们的产品寻找最佳销售渠道。

第六，维护和管理设备。

对于工厂设备的维护和管理是保证生产线平稳运转的必要条件。

增加回收利用的动力和无废物排放工厂的理想在下个十年里是影响工业开展 的主要因素。
5
Bulk chemical industry: 大化工
Unit 6 Chlor-Alkali and Related Processes
The segment is normally taken to include~~~~.
9
These are used by industries that need the liquid sodium, mainly in the production of tetra-alkyl lead petroleum additives, though the petroleum additive companies are diversifying and other uses may appear.
The industry will move more to serving the rest of the chemical industry and less to serving the farming industry.
工业将趋向于效劳化学工业的其余局部，而不是农业。
Another threat is the perceived environmental messiness of many large-scale
Extent of branching: 支链长度 Crossing-linking: 交联
Random copolymer: 无规共聚物 Alternating copolymer:交替共聚物 Block copolymer: 嵌段共聚物
Multiply: 增加
同一聚合物根据最终的应用有许多不同级别，例如说，不同的分子量、分子量分布、 支链长度、交联等等，当考虑到共聚物时〔无规共聚物，交替共聚物，嵌段共聚物〕， 这些级别还会增加。

Lesson 1Chemical Engineering1、What is chemical engineering and its content?The Institution of Chemical Engineers defines chemical engineering as “that branch of engineering which is concerned with processes in which materials undergo a required change in composition, energy content or physical state: with the means of processing; with the resulting products, and with their application to useful ends”.2、What concept is the landmark in the development of chemical engineering?Unit operations3、What are the basic laws of chemical engineering science?The principles of chemistry, physics, and mathematics.The laws of physical chemical and physics govern the practicability and efficiency of chemical engineering operations. Energy changes, deriving from thermodynamics consideration, are particularly important. Mathematics is a basic tool in optimization and modeling.4、Name the functions and branches of chemical engineering you know.Chemical Engineering Functions: The design and development of both processes and plant items.Branches of Chemical Engineering: Plastics, polymers, synthetic fibers, dyeing, pulp and paper manufactures, pharmaceutical industry, and separation of rare metals.Lesson 2 Chemical Equilibrium and Kinetics1、Which factors influence the reaction rates?a)Temperatureb)concentrations of reactants (or partial pressure of gaseous reactants)c)presence of a catalyst.2、How to determine the reaction equilibrium constants?For a reversible reaction：aA + bB = cC +dDthe equilibrium constant expression is written as follows:K = C c D d / A a B bLesson 3 The Second Law of Thermodynamics1、What are the applications of chemical thermodynamics?There is two major applications of thermodynamics:( i ) The calculation of heat and work effect associated with processes as well as the calculation of the maximum work obtainable from a process or the minimum work required to drive a process.( ii ) The establishment of relationship among the variables describing systems at equilibrium.Lesson 4 Chemical Reaction Engineering1、Homogeneous Reactions vs. Heterogeneous ReactionsHomogeneous reactions are those in which the reactants, products, and any catalyst used form one continuous phase; gaseous and liquid.Heterogeneous reactions are those in which two or more phases exist, and the overriding problem in the reactor design is to promote mass transfer between the phases. The possible combinations of phase are:( i ) Liquid-liquid ( ii ) Liquid-solid ( iii ) Liquid-solid-gas( iv ) Gas-solid ( v ) Gas-liquid2、Reactor Geometry(type)Stirred Tank ReactorsTubular ReactorsPacked Bed ReactorsFluidized Bed ReactorsLesson 5 Chlor-Alkali and Related Processes1、What are the mechanisms of chlor-alkali process?The reaction are based on the idea of using electrons as a reagent in chemical reactions. The basic reactions of brine electrolysis can be written as follows:Anode 2Cl- - 2e-—> Cl2Cathode 2H2O + 2e-—> H2 + 2OH-The overall reaction is: 2Na+ + 2Cl- + 2H2O —> NaOH + Cl2 + H2Lesson 7 Momentum, Heat, and Mass Transfer1、In some cases, momentum , heat and mass transfer all occurs simultaneously, explain with examples.In a water-cooling tower, where transfer of sensible heat (heat transfer) and evaporation (mass transfer) both take place from the surface of the water droplets. Momentum transfer take place between the water droplets and air.2、What will happen for two adjacent layers of fluid with different moving velocities?There will be a tendency for the faster moving layer to be retarded and the slower moving layer to be accelerated by virtue of the continuous passage of molecules in each direction. There will be a net transfer of momentum from the fast to the slow moving stream.Lesson 10 Gas Absorption1、There are three ways in which a large contact area can be established:1. The liquid is brought in contact with the gas in the form of thin films ( film scrubbers).2. The liquid is dispersed in the gas in the form of minute drops (spray scrubbers).3. The gas is dispersed in the liquid in the form of small bubbles (bubble scrubbers). All apparatus applied in gas absorption practice is based on one of these three principles or on a combination of them.Lesson 13 Filtration1、Which factors should be considered in the operation of filtration?a)The properties of the liquid , particularly its viscosity, density and corrosive properties.b)The nature of the solid - its particle size and shape, size distribution, and packing characteristics.c)The concentration of solids in suspension.d)The quality of material to be handled, and its value.e)Whether the valuable product is the solid, the fluid, or both.f)Whether it is necessary to wash the filtered solids.g)Whether very slight contamination caused by contact of the suspension or filtrate with the various components of the equipment is detrimental to the product.h)Whether the feed liquor may be heated.i)Whether any form of pretreatment would be helpful.2、Which factors will have a close relation with the rate of filtration?a) The drop in pressure from the feed to the far side of the filter medium.b) The area of the filtering surface.c) The viscosity of the filtrate,d) The resistance of the filter cake.e) The resistance of the filter medium and initial layers of cake.Lesson 15 Computer-Assisted Design of New Process1、Design for new processed proceed through at least three stagesConceptual Design: the generation of ideas for new processes (processed synthesis) and their translation into an initial design. This stage includes preliminary cost estimates to asses the potential profitability of the process, as well as analyses of process safety andenvironmental considerations.Final Design: a rigorous set of design calculations to specify all the significance details of a process,Detailed Design: preparation of engineering drawing and equipment lists needed for construction.TBC ...Lesson 16 Catalysis1、Catalytic reactions can be classified into three types:The most common is heterogeneous catalysis, in which the catalyst is a solid and the reactants and products are either gases or liquids. The second type is homogeneous catalysis, in which the reactants, products and catalyst are molecularly dispersed in a single phase, usually the liquid phase. The third type is enzyme catalysis.Lesson 18 Polymers and Polymerization Techniques1、There are five general methods of polymerization:( i ) Bulk (or mass) ( ii ) Solution ( iii ) Slurry (or precipitation)( iv ) Suspension(or dispersion) ( v) EmulsionFurther lesser-used methods include:( vi ) Interfacial ( vii ) Reaction injection moulding (RIM)( viii ) Reactive processing of molten polymers2、A polymerization process consists of three stages:( i ) Monomer preparation ( ii ) Polymerization ( iii ) Polymer recover。

Fine 1.n.罚金，罚款
2.v.以（sb）以罚款
3.adj.美好的完美的优秀的/纤细的，尖细的thin thick厚，粗大
4.adv=well好
14.the longer the wire，the greater is its resistance导线越长，他的电阻越大
The area of its cross section横截面积
Electric cell /battery：电池
Chemical action化学反应
One…the other …：一个…另一个（两个）
One…another…：一个…另一个(三个以上)
2.mechanical energy机械的用机械的制
Electric energy：电能
Change…into…把…转化成…
Go out烧坏
ed up用尽耗光
There is therefore因此
At any one instant of time在任何时刻
12.the resistance of any conductor任何导体的电阻
The same diameter直径
13.fine wires have greater resistance than big wires of the same length
Direct currentDC
Alternating current AC
In the same direction在相同的方向
7.A generator converts mechanical rotational power into electric energy and may be called a prime same of emf发电机将旋转的机械能，可以被称为电动势的主要来源

Periodic Trends for Ionization Energy Ionization Energy is the amount of energy required to remove an electron from a neutral atom in its gaseous phase. Conceptually, ionization energy is considered the opposite of electronegativity. The lower this energy is, the more readily the atom becomes a cation.
As you move to the right across a period of elements, electronegativity increases. When the valence shell of an atom is less than half full, it requires less energy to lose an electron than gain one and thus, it is easier to lose an electron. Conversely, when the valence shell is more than half full, it is easier to pull an electron into the valence shell than to donate one.
Lesson 3 Periodic Table
2015-5-12 1
• 在元素周期表（periodic tablet of elements）中， 元素可分为几大类（category）：碱金属（alkali metals）、碱土金属（alkaline earth metals）、 内过渡元素（inner transition elements）、镧系 金属（lanthanides）、锕系金属（actinides）、 过渡元素（transition elements）、其它金属 （other metals）、准金属/半金属元素 （metalloids）、其它非金属（other nonmetals） 、卤素（halogens）、惰性气体（noble gases）及 未知（unknown）。

• Throughout （表示时间）自始至终； 在…期间； 遍及…地域；
• Manufacture of chemicals in the mid-19th century consisted of modest craft operations. • Craft 工艺；手艺；技巧；技能
• Increase in demand,public concern at the emission of noxious effluents,and competition between rival processes provided the incentives for greater
• The laws of physical chemistry and physics govern
the practicability and efficiency of chemical engineering operations. • Practicability 实用性
• Energy changes,deriving from thermodynamic considerations, are particulary important.
• The number of unit operation-the building blocks of a chemical plant-is not large.
• The complexity arises from the variety of conditions under which the unit operations are conducted.
Specialized English for chemistry
Chemical Enineering and Technology

2)Check work. Ask the Ss to read out their new words in individuals.Get each of them read one or two words, if he or she makes any mistakes, ask the class to correct them.
教学方法与手段
5
Mins
10
mins
Step 1 Greeting
Try to cheer up the Ss with interesting greeting and short humor.
Step 2 Introduction
A titration is an analytical procedure in which a reagent called a titrant is slowly added to another substance. A rapid stoichiometric reaction takes place as the titrant is added, and both the addition and
amount, or the concentration, of one of the reactants, which can be
done if the amount, or concentration and volume, of the other reactant required to reach the endpoint of the titration is known.
广西石化高级技工学校
课堂教案（理论）
任课教师：莫竹浪科目：化学化工专业英语授课班级：12化工1/2/3/石油化工

Part 2 Unit 1. 元素、化合物和物质元素是用一般的化学方法无法使之分解为更简单物质的纯物质。

总的来说, 到2008年, 已经发现的元素有117种, 其中94种是地球上天然存在的元素。

人们熟悉的一些常见元素有碳、氢、氧、氮、磷、钾、硫、铝、铁、铜和金。

这些元素是物质组成的基本单元, 就像数字但是由0 - 9组成一样。

众所周知, 整个宇宙也同样是由这些已经在地球上发现的元素所构成。

这些自然界中存在的元素和其他元素结合在一起形成了矿物质、植物或水和二氧化碳等物质。

铜、银、金和其它20多种元素可以以高纯度形式存在于自然界中。

还有16种元素是自然界中没有发现的，这些元素是在核爆炸和核研究中所产生的少量物质。

因而，他们都是人造元素。

由两个或两个以上元素组成的纯物质称为化合物。

因为化合物含有两种或更多的元素, 因而其与元素的性质不同, 他们可以通过化学变化分解成更简单的物质。

化合物经化学分解最终产生的物质正是组成化合物的元素。

组成化合物的元素的原子以整数比例，而非以分数比，结合在一起。

(组成化合物的元素各原子间以整数比例而非分数比结合在一起)原子间相互结合形成的化合物以分子或离子状态存在。

一个化合物的分子是由两个或两个以上的原子组成的，化合物的分子体积很小，而且不带电(呈电中性).如果我们把一滴水细分成越来越小的微粒, 我们最终可以得到一个水的单体，即一个水分子。

这个水分子是由两个氢原子和一个氧原子键合在一起。

人们通常无法进一步分解分子单元, 只有破坏分子结构才能将其分解成所组成的元素。

因此, 水分子是水这种化合物的最小单元。

离子是带正电的或负电的原子或元素簇。

一个化合物中的离子依靠它们正电和负电基团间的相互引力结合在一起, 形成晶体结构。

由离子组成的化合物中不存在分子。

氯化钠是一种典型的非分子结构的化合物。

这类化合物包含大量的正、负离子, 其分子式如分子结构的化合物那样，通常采用组成化合物的原子间以简单比例式方式来表达。

The Second Law of Thermodynamics热力学第二定律Thermodynamics is concerned with transformation of energy, and the laws of thermodynamics describe the bounds within which these transformation are observed to occur.热力学讨论的是能量的转换，热力学定律描述了这些转变能够发生的边界条件。

The first law, stating that energy must be conserved in all ordinary processes, has been the underlying principle of the preceding chapters.第一定律指出了在一般过程中，能量是守恒的，它是前面章节遵循的根本原则。

The first law imposes no restriction on the direction of energy transformation.第一定律对能量转换的方向性没有限制。

Yet, all our experience indicates the existence of such a restriction.然而，我们的经验说明这种限制的存在。

To complete the foundation for the science of thermodynamics, it is necessary to formulate this second limitation. Its concise statement constitutes the second law.为了完善热力学的科学基础，有必要规定第二个限制条件，它简洁的容构成了第二定律。

The differences between the two forms of energy, heat and work, provide some insight into the second law.两种形式的能量：热和功之间的不同，为第二定律提供了一些见解。