《专业英语 English for Special Purpose》课程PPT教学课件：第一篇 专业英语基础 第1章 绪论

专业英语 Lecturer: Mr Lu Hongming Te:0515-3127908 Email:Thmyg@sina.com

Lecturer：Mr. Lü Hongming Tel：0515-3127908 Email: lhmyg@sina.com

第一篇专业英语基础 第1章绪论 1.1概述 1.课程教学目的 培养学生对专业语言的理解能力和应用能 力;让学生承担专业阅读必需的基本技能和 知识,使学生能够以英语为工具获取专业科 技知识及其他与专业有关的信息

1.1 概述 第一篇 专业英语基础 第1章 绪 论 1. 课程教学目的 培养学生对专业语言的理解能力和应用能 力；让学生承担专业阅读必需的基本技能和 知识，使学生能够以英语为工具获取专业科 技知识及其他与专业有关的信息

2.专业英语的起源 最初出现于20世纪50年代。 3.专业英语的教学特点 语言教学密切结合专业知识,教材大都 来源于相关的专业文献

2. 专业英语的起源 最初出现于20世纪50年代。 3. 专业英语的教学特点 语言教学密切结合专业知识，教材大都 来源于相关的专业文献

4.专业英语的学习方法 专业英语阅读与普通英语的快速阅读的方 法也所不同,专业英语阅读要把准理解放在 首位,在准往确理解的基础上提高阅读速度。 和其他的英语能力一祥,专业英语阅读能力 需要通过长期的实践才能获得,不可能一蹴 而就,多读多练是提高专业英语阅读能力的 最有效的方法

4. 专业英语的学习方法 专业英语阅读与普通英语的快速阅读的方 法也所不同，专业英语阅读要把准理解放在 首位，在准确理解的基础上提高阅读速度。 和其他的英语能力—祥，专业英语阅读能力， 需要通过长期的实践才能获得，不可能一蹴 而就，多读多练是提高专业英语阅读能力的 最有效的方法

1.2专业英语的基本特点 为了了解专业英语的特点,我们先阅读下面一段关于许用应力的课文 Despite the tests described in Chapters 1l and 12, materials may still fail in service, sometimes with disastrous results (e.g. when the failure occurs in aircraft. bridges, ships, etc. ) To try to avoid such disastrous occurring, the designer avoids using materials continuously at their maximum allowable stress. This is done by employing a factor ot satety Unfortunately, increasing the strength of a component in the interests of safety not only increases the initial material costs, but also the operating costs. For example, the stronger and heavier the structure members of an aircraft, the fewer passengers it can carry and the more fuel it consumers. Therefore a balance has to be maintained between safety, initial cost and operating costs. The designer is constantly striving to improve the former whilst reducing the latter

1.2 专业英语的基本特点 为了了解专业英语的特点，我们先阅读下面一段关于许用应力的课文。 Despite the tests described in Chapters 1l and 12，materials may still fail in service，sometimes with disastrous results (e.g. when the failure occurs in aircraft．bridges，ships，etc.). To try to avoid such disastrous occurring，the designer avoids using materials continuously at their maximum allowable stress. This is done by employing a factor of safety. Unfortunately，increasing the strength of a component in the interests of safety not only increases the initial material costs，but also the operating costs. For example，the stronger and heavier the structure members of an aircraft，the fewer passengers it can carry and the more fuel it consumers．Therefore a balance has to be maintained between safety，initial cost and operating costs．The designer is constantly striving to improve the former whilst reducing the latter．

Allowable working stress is taken as a proportion of the yield or proof stress; that is, the component is only stressed within its elastic range when in service. For example, consider the screwed fastening shown in Fig. 1.I. When the nut is tightened normally the bolt is stretched slightly and, providing it is stressed within its elastic range, it will behave like a very powerful spring and will pull the joint faces together very firmly. 上投代 Figl.1 Screwed Fastening

Allowable working stress is taken as a proportion of the yield or proof stress；that is，the component is only stressed within its elastic range when in service．For example, consider the screwed fastening shown in Fig. 1.l. When the nut is tightened normally the bolt is stretched slightly and，providing it is stressed within its elastic range，it will behave like a very powerful spring and will pull the joint faces together very firmly．

The stress in the bolt is made up of two elements. Firstly. the stress imparted by the initial tightening of the bolt: secondly, the stress imparted by the load on the fastening in service. The sum of these stress must not be allowed to approach, let alone ceed, the yield stress for the material of it will cease to act in an elastic manner. Therefore the designer proportions the fastening(another components) so as that there is a factor of safety. Usually the designer assumes an allowable working stress of only half the yield stress for the material

The stress in the bolt is made up of two elements. Firstly, the stress imparted by the initial tightening of the bolt; secondly， the stress imparted by the load on the fastening in service．The sum of these stress must not be allowed to approach，let alone exceed，the yield stress for the material of it will cease to act in an elastic manner．Therefore the designer proportions the fastening (another components) so as that there is a factor of safety．Usually the designer assumes an allowable working stress of only half the yield stress for the material

If the fastening shown in Fig. 1. 1 is overstressed by applying excess torque to the nut(for example, by extending the length of the spanner with a tube), the bolt will be stressed beyond its elastic range. Once the yield stress for the bolt has been exceeded it exhibits plastic properties and takes a permanent set that is, it becomes permanently lengthened, the spring back "is seriously reduced and the joint faces are no longer held firmly together. Thus for critical assemblies, the designer will seek to control the stress in the fastening and associated components by specifying the torque to be applied to the nut as it is tightened by the use of a torque spanner"set to a specific value

If the fastening shown in Fig. 1.1 is overstressed by applying excess torque to the nut (for example，by extending the length of the spanner with a tube)，the bolt will be stressed beyond its elastic range．Once the yield stress for the bolt has been exceeded it exhibits plastic properties and takes a permanent set that is，it becomes permanently lengthened，the “spring back” is seriously reduced and the joint faces are no longer held firmly together. Thus for critical assemblies，the designer will seek to control the stress in the fastening and associated components by specifying the torque to be applied to the nut as it is tightened by the use of a “torque spanner” set to a specific value

可以得出专业英语的特点: 1.在文章结构方面,逻辑严谨,层次分明,复杂长句多; 2.在用词方面,必然要用到专业术语和专业单词,以及词 性变换多; 3.在语法方面,非谓语动词多,较多地使用被动语态; 4.另一个重要特点是采用图表等非语言因素表达思想

1. 在文章结构方面，逻辑严谨，层次分明，复杂长句多； 2. 在用词方面，必然要用到专业术语和专业单词，以及词 性变换多； 3. 在语法方面，非谓语动词多，较多地使用被动语态； 4. 另一个重要特点是采用图表等非语言因素表达思想。 可以得出专业英语的特点：

★复杂长句多 ■语法分析 符合汉语习惯 以短代长、化难为易 Factories will not buy machines unless they believe that the machine will produce goods that they are able to sell to consumers at a price that will cover all cost

★复杂长句多 ■语法分析 ■符合汉语习惯 ■以短代长、化难为易 Factories will not buy machines unless they believe that the machine will produce goods that they are able to sell to consumers at a price that will cover all cost