专业英语5讲述优秀PPT.ppt

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1、The course ofSpecial English for Mechanical EngineeringTeacher：Li Yujuan转换词性是依据翻译的须要将英语某一词性的词译为汉转换词性是依据翻译的须要将英语某一词性的词译为汉语另一词性的方法。语另一词性的方法。例：例：The workers have succeeded in making high quality semiconductor devices of all types.工人们成功地制造了各种类型高质量的半导体装置。工人们成功地制造了各种类型高质量的半导体装置。(汉汉语不说工人们在语不说工人们在方面成功，而把动词方

2、面成功，而把动词“succeed”译为译为副词副词成功地成功地)在以下状况下可考虑转换词性：在以下状况下可考虑转换词性：-当英语某一词性的词相当于汉语另一词性时；当英语某一词性的词相当于汉语另一词性时；-当某词按同一词性翻译不能精确表达该词的意义时；当某词按同一词性翻译不能精确表达该词的意义时；-当某词按同一词性翻译而使得汉语句子不通顺时。当某词按同一词性翻译而使得汉语句子不通顺时。翻译的基本方法翻译的基本方法4转换词性转换词性Skills of Translation transform part of speech 1.转换为汉语的名词转换为汉语的名词1）动词转换为汉语名词）动词转换为汉语

3、名词Has the house been wired for electricity?这房子的电线装好了吗？（动词这房子的电线装好了吗？（动词wired 译为译为“装线装线”“给给装电装电线线”）Vacuum rectifiers are characterized by the following.真空整流器具有如下的特性。真空整流器具有如下的特性。Properties of non-metals vary widely.非金属材料的各种性能有很大的差异。非金属材料的各种性能有很大的差异。(不宜译为不宜译为“性能变更性能变更很大很大”)However,we observe that the

4、a.c.ammeter reads about 1A.然而然而,我们看到我们看到,沟通电表的读数为大约沟通电表的读数为大约1安培。安培。(不译不译:读为大约读为大约1安安)转换词性转换词性2 2）形容词转换为汉语名词）形容词转换为汉语名词）形容词转换为汉语名词）形容词转换为汉语名词Most materials used in engineering are elastic.Most materials used in engineering are elastic.工程中所用的大多数材料都具有弹性。（而不说工程中所用的大多数材料都具有弹性。（而不说工程中所用的大多数材料都具有弹性。（而不说工程

5、中所用的大多数材料都具有弹性。（而不说“是弹性的是弹性的是弹性的是弹性的”）Computers are more flexible,and can do a greater Computers are more flexible,and can do a greater variety of jobs.(variety of jobs.(汉语不说汉语不说汉语不说汉语不说“计算机是更灵敏的计算机是更灵敏的计算机是更灵敏的计算机是更灵敏的”，把，把，把，把“灵敏的灵敏的灵敏的灵敏的”改译成改译成改译成改译成“灵敏性灵敏性灵敏性灵敏性”)”)计算机的灵敏性比较大，因此能做更多种不同的工作。计算机的灵

6、敏性比较大，因此能做更多种不同的工作。计算机的灵敏性比较大，因此能做更多种不同的工作。计算机的灵敏性比较大，因此能做更多种不同的工作。Jet engines are very powerful.Jet engines are very powerful.喷气发动机的功率特殊大。喷气发动机的功率特殊大。喷气发动机的功率特殊大。喷气发动机的功率特殊大。(若将若将若将若将“Powerful”“Powerful”译为强大的，译为强大的，译为强大的，译为强大的，未能表达未能表达未能表达未能表达“功率功率功率功率”这一概念，使词义不明确。这一概念，使词义不明确。这一概念，使词义不明确。这一概念，使词义不明

7、确。)The microscope serves to render the small larger.The microscope serves to render the small larger.显微镜能使小物体变大。显微镜能使小物体变大。显微镜能使小物体变大。显微镜能使小物体变大。(the small(the small 转换成名词转换成名词转换成名词转换成名词“小物体小物体小物体小物体”)”)转换词性转换词性3)副词转换为汉语名词副词转换为汉语名词Sodium and copper have one electron in the outer shell and are chemic

8、ally similar.钠和铜在外壳上具有一个电子，因而其化学性质相像。（不说钠和铜在外壳上具有一个电子，因而其化学性质相像。（不说“化化学地相像学地相像”而是将而是将chemically 译为译为“化学性质化学性质”）This loss may be partially reduced by using cores of silicon steel or of certain other alloys.(汉语不说汉语不说“部分地削减部分地削减”)接受硅钢芯或其它合金做的芯可使这种损耗削减一部分。接受硅钢芯或其它合金做的芯可使这种损耗削减一部分。4)代词转换为汉语名词代词转换为汉语名词The

9、 properties of semiconductors are different from those of conductors.半导体的性质与导体的性质大不相同。（将半导体的性质与导体的性质大不相同。（将these还原译为还原译为“性质性质”）转换词性转换词性2.转换为汉语的动词转换为汉语的动词1)名词或动名词转换为汉语动词名词或动名词转换为汉语动词One of the principal rules of the lathe maintenance is timely lubrication of all friction surfaces.车床维护的主要规律之一就是刚好润滑全部摩

10、擦面。车床维护的主要规律之一就是刚好润滑全部摩擦面。The voltmeter is an electrical instrument for measurement of voltage.伏特计是用来测量电压的仪表。伏特计是用来测量电压的仪表。2）形容词或）形容词或“形容词形容词+介词介词”转换为汉语动词转换为汉语动词We are also familiar with other transformations of energy.我们还熟悉别的能量转换现象。我们还熟悉别的能量转换现象。The force is perpendicular to the surface.此力垂直于表面。此力垂

11、直于表面。转换词性转换词性3）副词转换为汉语动词）副词转换为汉语动词Engineers took the machine apart yesterday.工程师昨天把这台机器拆开了。工程师昨天把这台机器拆开了。Now the experiment is over.现在试验结束。现在试验结束。The reaction force to this action force pushes rocket ship along.这个作用力所产生的反作用力推动宇宙飞船前进。这个作用力所产生的反作用力推动宇宙飞船前进。4）介词或介词短语转换为汉语动词）介词或介词短语转换为汉语动词The applicatio

12、n of plastics is on the increase.塑料的应用正在增多。塑料的应用正在增多。The number of tools stored in the drum is above forty.刀库中储存的刀具超过四十把。刀库中储存的刀具超过四十把。转换词性转换词性3.转换为汉语的形容词转换为汉语的形容词1）副词转换为汉语形容词）副词转换为汉语形容词Why is electricity widely used in industry?为什么电在工业中得到广泛的运用呢？为什么电在工业中得到广泛的运用呢？Gases and liquids are perfectly elast

13、ic.气体与液体都有良好的弹性。气体与液体都有良好的弹性。2）名词转换为汉语形容词）名词转换为汉语形容词When an excess of electrons is present,we may call the material n-type;when a lack of orbital electrons occurs,we call the material p-type.当呈现多余的电子时，我们称之为当呈现多余的电子时，我们称之为n型材料，当缺乏轨道电子时，型材料，当缺乏轨道电子时，我们称之为我们称之为p型材料。（将型材料。（将“电子的过剩电子的过剩”译为译为“多余的电子多余的电子”）

14、转换词性转换词性4.转换为汉语的副词转换为汉语的副词1)形容词转换为汉语副词形容词转换为汉语副词A graph gives a visual representation of the relationship.图能直观地表示所要说明的关系。图能直观地表示所要说明的关系。(形容词形容词visual“视觉的视觉的”转换成副词转换成副词“直观地直观地”)To the successful research,manufacture and launching of Chinas astronautic vehicle,our space industry has already make great

15、 contributions.我国航天工业对成功地探讨、生产和放射宇宙飞船做出了巨大的贡我国航天工业对成功地探讨、生产和放射宇宙飞船做出了巨大的贡献。（形容词献。（形容词successful 转换成副词）转换成副词）The molecules are still free to move about.分子仍可自由运动。（形容词分子仍可自由运动。（形容词free 译成副词，修饰动词译成副词，修饰动词“运动运动”。）。）转换词性转换词性2 2）动词转换为汉语副词）动词转换为汉语副词）动词转换为汉语副词）动词转换为汉语副词In the long and laborious search,Marie

16、Curie In the long and laborious search,Marie Curie succeeded in isolating two new substances.succeeded in isolating two new substances.在长期辛勤的探讨中，玛利居里成功地分解出两种新物质。在长期辛勤的探讨中，玛利居里成功地分解出两种新物质。在长期辛勤的探讨中，玛利居里成功地分解出两种新物质。在长期辛勤的探讨中，玛利居里成功地分解出两种新物质。（动词（动词（动词（动词succeed succeed 转译成副词转译成副词转译成副词转译成副词“成功地成功地成功地成功地

17、”）3 3）名词转换为汉语副词）名词转换为汉语副词）名词转换为汉语副词）名词转换为汉语副词Gears may be form cut on a milling machine.Gears may be form cut on a milling machine.齿轮可以在铣床上成形切削。（齿轮可以在铣床上成形切削。（齿轮可以在铣床上成形切削。（齿轮可以在铣床上成形切削。（form form 修饰修饰修饰修饰 cut cut）Most of machine parts are mass produced.Most of machine parts are mass produced.大多数机器零

18、件是批量生产的。（大多数机器零件是批量生产的。（大多数机器零件是批量生产的。（大多数机器零件是批量生产的。（mass mass 修饰修饰修饰修饰 produced produced）Several cutters are arbor mounted on the spindle of a Several cutters are arbor mounted on the spindle of a milling machine.milling machine.铣床主轴上可借助刀杆装上几把铣刀。（铣床主轴上可借助刀杆装上几把铣刀。（铣床主轴上可借助刀杆装上几把铣刀。（铣床主轴上可借助刀杆装上几把铣

19、刀。（arbor arbor 修饰修饰修饰修饰 mountedmounted）转换词性转换词性Lesson5 Keys,Couplings and Seals A Key is the machinery component placed at the A Key is the machinery component placed at the interface between a shaft and the hub of a power-interface between a shaft and the hub of a power-transmitting element for the

20、 purpose of transmitting element for the purpose of transmitting torque(see Figure 1.6(a).The key is transmitting torque(see Figure 1.6(a).The key is demountable to facilitate assembly and disassembly demountable to facilitate assembly and disassembly of the shaft system.It is installed in an axial

21、groove of the shaft system.It is installed in an axial groove machined into the shaft,called a keyset.machined into the shaft,called a keyset.键是一种位于轴和动力传递的轮毂之间用于传递扭键是一种位于轴和动力传递的轮毂之间用于传递扭键是一种位于轴和动力传递的轮毂之间用于传递扭键是一种位于轴和动力传递的轮毂之间用于传递扭矩的机械零件（参见图矩的机械零件（参见图矩的机械零件（参见图矩的机械零件（参见图1.61.6（a a）。键是可拆卸的，）。键是可拆卸的，）。

22、键是可拆卸的，）。键是可拆卸的，以便利轴系统的装配和拆卸。它安装在一个轴向槽以便利轴系统的装配和拆卸。它安装在一个轴向槽以便利轴系统的装配和拆卸。它安装在一个轴向槽以便利轴系统的装配和拆卸。它安装在一个轴向槽加工成的轴，称为键槽。加工成的轴，称为键槽。加工成的轴，称为键槽。加工成的轴，称为键槽。A similar groove in the hub of the power-A similar groove in the hub of the power-transmitting element is usually called a keyway,transmitting element i

23、s usually called a keyway,but it is more properly also a keyset.The key is but it is more properly also a keyset.The key is typically installed into the shaft keyset first;then typically installed into the shaft keyset first;then the hub keyseat is aligned with the key,and the the hub keyseat is ali

24、gned with the key,and the hub is said into position.hub is said into position.一个类似的在动力传输元素间枢纽凹槽，通常被一个类似的在动力传输元素间枢纽凹槽，通常被一个类似的在动力传输元素间枢纽凹槽，通常被一个类似的在动力传输元素间枢纽凹槽，通常被称为键沟，但更恰当的应当叫键槽。键通常被首称为键沟，但更恰当的应当叫键槽。键通常被首称为键沟，但更恰当的应当叫键槽。键通常被首称为键沟，但更恰当的应当叫键槽。键通常被首先安装到轴的键槽，然后轮毂键槽与键对齐，轮先安装到轴的键槽，然后轮毂键槽与键对齐，轮先安装到轴的键槽，然后轮

25、毂键槽与键对齐，轮先安装到轴的键槽，然后轮毂键槽与键对齐，轮毂就安装到位了。毂就安装到位了。毂就安装到位了。毂就安装到位了。1.Square and Rectangular parallel Keys1.Square and Rectangular parallel KeysThe most common type of key for shafts up to 6.5 inches The most common type of key for shafts up to 6.5 inches in diameter is the square key,as illustrated in Fi

26、gure in diameter is the square key,as illustrated in Figure 1.6(b).The rectangular key(illustrated in Figure 1.6(c)1.6(b).The rectangular key(illustrated in Figure 1.6(c)is recommended for larger shafts and is used for smaller is recommended for larger shafts and is used for smaller shafts where the

27、 shorter height can be tolerated.Both shafts where the shorter height can be tolerated.Both the square and the rectangular keys are referred to as the square and the rectangular keys are referred to as parallel keys because the top,bottom and the sides of the parallel keys because the top,bottom and

28、 the sides of the key are parallel.key are parallel.1.1.方键和矩形键方键和矩形键方键和矩形键方键和矩形键最常见的键是轴直径为最常见的键是轴直径为最常见的键是轴直径为最常见的键是轴直径为6.56.5英寸的方键，如在图英寸的方键，如在图英寸的方键，如在图英寸的方键，如在图1.61.6（b b）项所示。长方形键（在图项所示。长方形键（在图项所示。长方形键（在图项所示。长方形键（在图1.61.6（C C）所示）一般用于较大）所示）一般用于较大）所示）一般用于较大）所示）一般用于较大的轴，或用于较短的可承受载荷的小轴。方形和长方形的轴，或用于较短的

29、可承受载荷的小轴。方形和长方形的轴，或用于较短的可承受载荷的小轴。方形和长方形的轴，或用于较短的可承受载荷的小轴。方形和长方形都因为顶部，底部和键的两侧是平行的被称为平行键。都因为顶部，底部和键的两侧是平行的被称为平行键。都因为顶部，底部和键的两侧是平行的被称为平行键。都因为顶部，底部和键的两侧是平行的被称为平行键。The keyseats in the shaft and the hub are designed The keyseats in the shaft and the hub are designed so that exactly one-half of the height

30、of the key is so that exactly one-half of the height of the key is bearing on the side of the shaft keyseat and the bearing on the side of the shaft keyseat and the other half on the side of the hub keyseat.other half on the side of the hub keyseat.特地设计了在轴和轮毂的键槽，因此事实上键高特地设计了在轴和轮毂的键槽，因此事实上键高特地设计了在轴和轮

31、毂的键槽，因此事实上键高特地设计了在轴和轮毂的键槽，因此事实上键高度的度的度的度的1.51.5倍在承受轴的键槽的力，另一半力轮毂的倍在承受轴的键槽的力，另一半力轮毂的倍在承受轴的键槽的力，另一半力轮毂的倍在承受轴的键槽的力，另一半力轮毂的轴承受。轴承受。轴承受。轴承受。2.Couplings2.Couplings The term coupling refers to a device used to The term coupling refers to a device used to connect two shafts together at their ends for the co

32、nnect two shafts together at their ends for the purpose of transmitting power.There are two purpose of transmitting power.There are two general types of couplings:rigid and flexible.general types of couplings:rigid and flexible.2.2.联轴器联轴器联轴器联轴器联轴器就是一种用来连接两根轴末端的，用于联轴器就是一种用来连接两根轴末端的，用于联轴器就是一种用来连接两根轴末端

33、的，用于联轴器就是一种用来连接两根轴末端的，用于传递动能的装置。一般分为两种：刚性和柔性。传递动能的装置。一般分为两种：刚性和柔性。传递动能的装置。一般分为两种：刚性和柔性。传递动能的装置。一般分为两种：刚性和柔性。1).rigid couplings1).rigid couplings Rigid couplings are designed to draw two shafts Rigid couplings are designed to draw two shafts together tightly so that no relative motion can occur toget

34、her tightly so that no relative motion can occur between them.This design is desirable for certain between them.This design is desirable for certain kinds of equipment in which precise alignment of kinds of equipment in which precise alignment of two shafts is required and can be provided.In such tw

35、o shafts is required and can be provided.In such cases,the coupling must be designed to be capable cases,the coupling must be designed to be capable of transmitting the torque in the shafts.of transmitting the torque in the shafts.1).1).刚性联轴器刚性联轴器刚性联轴器刚性联轴器刚性联轴器被设计了用于将两个轴紧密联系在一起，刚性联轴器被设计了用于将两个轴紧密联系在

36、一起，刚性联轴器被设计了用于将两个轴紧密联系在一起，刚性联轴器被设计了用于将两个轴紧密联系在一起，所以它们之间没有相对运动可以发生。这种设计是所以它们之间没有相对运动可以发生。这种设计是所以它们之间没有相对运动可以发生。这种设计是所以它们之间没有相对运动可以发生。这种设计是为满足部分部分设备，必需将两轴精确对准。在这为满足部分部分设备，必需将两轴精确对准。在这为满足部分部分设备，必需将两轴精确对准。在这为满足部分部分设备，必需将两轴精确对准。在这种状况下，联轴器必需被设计成能够传送轴的扭矩。种状况下，联轴器必需被设计成能够传送轴的扭矩。种状况下，联轴器必需被设计成能够传送轴的扭矩。种状况下，联

37、轴器必需被设计成能够传送轴的扭矩。A typical rigid coupling is shown in Figure 1.7,in A typical rigid coupling is shown in Figure 1.7,in which flanges are mounted on the ends of each which flanges are mounted on the ends of each shaft and are drawn together by a series of bolts.shaft and are drawn together by a serie

38、s of bolts.The load path is then from the driving shaft to its The load path is then from the driving shaft to its flange,through the bolts,into the mating flange,flange,through the bolts,into the mating flange,and out to the drive shaft.The torque places the and out to the drive shaft.The torque pl

39、aces the bolts in shear.The total shear force on the bolts bolts in shear.The total shear force on the bolts depends on the radius of the bolt circle and the depends on the radius of the bolt circle and the torque.torque.如图如图如图如图1.71.7所示，刚性联轴器的凸缘安装在每个轴的两端，并所示，刚性联轴器的凸缘安装在每个轴的两端，并所示，刚性联轴器的凸缘安装在每个轴的两端，

40、并所示，刚性联轴器的凸缘安装在每个轴的两端，并用螺栓固定。传动路径从传动轴到联轴器的凸缘，螺栓，用螺栓固定。传动路径从传动轴到联轴器的凸缘，螺栓，用螺栓固定。传动路径从传动轴到联轴器的凸缘，螺栓，用螺栓固定。传动路径从传动轴到联轴器的凸缘，螺栓，通过另一个相连接的联轴器，传送到输出轴。扭矩在螺栓通过另一个相连接的联轴器，传送到输出轴。扭矩在螺栓通过另一个相连接的联轴器，传送到输出轴。扭矩在螺栓通过另一个相连接的联轴器，传送到输出轴。扭矩在螺栓上产生了剪切力。螺栓的总剪切力取决于螺栓圆周的半径上产生了剪切力。螺栓的总剪切力取决于螺栓圆周的半径上产生了剪切力。螺栓的总剪切力取决于螺栓圆周的半径上产

41、生了剪切力。螺栓的总剪切力取决于螺栓圆周的半径和扭矩的大小。和扭矩的大小。和扭矩的大小。和扭矩的大小。Rigid couplings should be used only when the alignment of Rigid couplings should be used only when the alignment of the two shafts can be maintained very accurately,not only the two shafts can be maintained very accurately,not only at the time of in

42、stallation but also during operation of the at the time of installation but also during operation of the machines.If significant angular,radial,or axial machines.If significant angular,radial,or axial misalignment occurs,stresses that are difficult to predict misalignment occurs,stresses that are di

43、fficult to predict and that may lead to early failure due to fatigue will be and that may lead to early failure due to fatigue will be induced in the shafts.These difficulties can be overcome by induced in the shafts.These difficulties can be overcome by the use of flexible couplings.the use of flex

44、ible couplings.两个轴不仅在安装时，而且在机器的运作过程中都要求保两个轴不仅在安装时，而且在机器的运作过程中都要求保两个轴不仅在安装时，而且在机器的运作过程中都要求保两个轴不仅在安装时，而且在机器的运作过程中都要求保持精确对心，这时应接受刚性联轴器。假如发生显著的角持精确对心，这时应接受刚性联轴器。假如发生显著的角持精确对心，这时应接受刚性联轴器。假如发生显著的角持精确对心，这时应接受刚性联轴器。假如发生显著的角度，径向或轴向偏差，应力很难预料并且可能会因乏累导度，径向或轴向偏差，应力很难预料并且可能会因乏累导度，径向或轴向偏差，应力很难预料并且可能会因乏累导度，径向或轴向偏差，

45、应力很难预料并且可能会因乏累导致轴的早期失效。这些困难是可以运用弹性联轴器进行克致轴的早期失效。这些困难是可以运用弹性联轴器进行克致轴的早期失效。这些困难是可以运用弹性联轴器进行克致轴的早期失效。这些困难是可以运用弹性联轴器进行克服。服。服。服。2).Flexible Couplings2).Flexible Couplings Flexible Couplings are designed to transmit Flexible Couplings are designed to transmit torque smoothly while permitting some axial,to

46、rque smoothly while permitting some axial,radial,and angular misalignment.The flexibility is radial,and angular misalignment.The flexibility is such that when misalignment does occur,parts of such that when misalignment does occur,parts of the coupling move with little or no resistance.Thus,the coup

47、ling move with little or no resistance.Thus,no significant axial or bending stresses are no significant axial or bending stresses are developed in the shaft.developed in the shaft.2).2).柔性联轴器柔性联轴器柔性联轴器柔性联轴器弹性联轴器被设计用于平稳传递扭矩，同时也允许弹性联轴器被设计用于平稳传递扭矩，同时也允许弹性联轴器被设计用于平稳传递扭矩，同时也允许弹性联轴器被设计用于平稳传递扭矩，同时也允许一些的轴向，

48、径向和角度偏差。柔性是指当轴心不一些的轴向，径向和角度偏差。柔性是指当轴心不一些的轴向，径向和角度偏差。柔性是指当轴心不一些的轴向，径向和角度偏差。柔性是指当轴心不重合时，联轴器的零件有不会发生相对移动。因此，重合时，联轴器的零件有不会发生相对移动。因此，重合时，联轴器的零件有不会发生相对移动。因此，重合时，联轴器的零件有不会发生相对移动。因此，轴上不存在显著的轴向弯曲应力。轴上不存在显著的轴向弯曲应力。轴上不存在显著的轴向弯曲应力。轴上不存在显著的轴向弯曲应力。Many types of flexible couplings are available Many types of flexi

49、ble couplings are available commercially.Each of them is designed to commercially.Each of them is designed to transmit a given limiting torque.The transmit a given limiting torque.The manufactures catalog lists the design data from manufactures catalog lists the design data from which you can choose

50、 a suitable coupling.which you can choose a suitable coupling.Remember that torque equals power divided by Remember that torque equals power divided by rotational speed.rotational speed.市面上有很多类型的柔性联轴器。每个联轴器只市面上有很多类型的柔性联轴器。每个联轴器只市面上有很多类型的柔性联轴器。每个联轴器只市面上有很多类型的柔性联轴器。每个联轴器只传递一个给定的有限的扭矩。生产商的产品书目传递一个给定的有限