科技英语短文-职称英语专用.pdf

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1、Unit 1 METALLURGYMetallurgy,Metallurgy is the study of metals and alloys.The mostimportant branch of metallurgy is the study of the methods ofextracting metals from the earth.Most metals occur only ascompounds in minerals.Only a few,such as gold,are founduncombined.Minerals that are mined for their

2、metals are called ores.Ores usually contained a mixture of different minerals.The amount ofmetals in an ore can vary greatly.Most iron is obtained from an orethat is almost pure iron oxide.Gold ore,on the other hand,may onlycontain one part of gold in a million.The first step is to crush the ore.The

3、n the material containing themetal is separated from the rest of the ore.The unwanted material iscalled the gangue.The material containing the metal is called theconcentrate.There are various methods of obtaining the metal fromthe concentrate.The method used depends on the metal.One common method is

4、 to heat the concentrate in air.Theoxygen in the air converts the metal into the metal oxide.Usually theoxide is then heated with carbon and a flux in a furnace.The carbonremoves the oxygen from the oxide and forms the gas carbon dioxide.This leaves behind the melted metal.The flux combines with oth

5、erimpurities in the concentrate.The impurities form a slag.Because themetals are heavy,the slag floats on top of the molten metal.The slagis then skimmed off.This method is used for metals such as iron andlead.Some ores are treated with an acid or some other substance.Thesubstance combines with the

6、metal to form a compound can beextracted by dissolving it in water.Gold is sometimes extracted by thismethod.The other common method is electrolysis.This method is usedfor very reactive metals such as aluminum and sodium.冶金学的研究对象是金属和合金，冶金学的最重要的分支是从矿物上提取金属。大多数金属以化合物的形式存在于矿物质中。只有少数金属如金，是单独存在的。用于提取金属的矿

7、物称为矿石，矿石通常含有不同矿物。矿石中的金属的含量很高。多数铁几乎是从纯的氧化铁的矿石中分离出来的。而金矿石，可能只包含百分之一的金子。首选是粉碎矿石。然后，将含有该金属的原料从矿石中分离出来。不需要部分被称为脉石，含有金属的部分被称为精矿。有各种方法将金属从精矿中分离出来。具体用方法取决于金属的性质。常用的方法是浓缩物在空气中加热。空气中的氧将金属氧化成金属氧化物。一般情况下，氧化物与碳和熔剂，在炉中的加热。碳与氧结合，形成的气体二氧化碳。反映后留下熔融金属。而溶剂和精矿中的杂质形成炉渣。因为金属的比重大，熔渣浮在熔融金属表面。然后被分离出去。此方法用于冶炼的金属包括铁和铅。某些矿石处理用

8、酸或一些其他物质处理。以化合物形式存在的金属（选择性地）溶解，可以通过将其溶解在水中好后提取出来。黄金有时通过该方法提取。另一种常见的方法是电解法。用于此方法适用于非常活泼的金属，如铝和钠。Questions:1 Whats metallurgy?Metallurgy is the study of metals and alloys.2、What are the methods used to get metals from the ores?One common method is to heat the concentrate in air.The oxygenin the air co

9、nverts the metal into the metal oxide.Some ores are treated with an acid or some other substance；The other common method is electrolysis.问题：1,什么是冶金吗？冶金是金属和合金的研究。2,什么是所使用的方法从矿石中的金属？一个常用的方法是浓缩物在空气中加热。的空气中的氧转化成金属氧化物的金属。某些矿石处理用酸或一些其他物质；另一种常见的方法是电解法。Unit 2 FURNACEA furnace is any enclosed structure in wh

10、ich fuel is burned toproduce heat.A furnace is usually made of metals or brick,or acombination of these or other fireproof substances.Furnaces aredesigned to produce the greatest amount of heat from the fuel used.They are also designed to direct the heat where it is most needed.Furnaces are used to

11、produce heat for comfort.They are also used toboil water to make steam,or to heat various substances.There are two main groups of furnaces.The first group consists offurnaces used for heating homes.Warm air furnaces may burn severalfuels,such as coal,coke,gasz or oil.These fuels heat air.Homefurnace

12、s must be cared for regularly.Cleaning furnaces maintains theirefficiency.It also helps to prevent fires.All furnaces,chimneys,and airducts should be serviced once every year.The sealing of furnace jointsshould be periodically checked.The second group of furnaces,what are those used in industry,are

13、used mainly to heat metals and make steam.They are also used inmaking cement,glass,bricks,steel,and many other materials.Industrial furnaces produce extremely high temperatures.Many ofthem use coal or coke for fuel.Other use gasz oil,or electricity.Oneindustrial furnace,the blast furnace,is a cone-s

14、haped structure ofbrick,concrete,and steel.The blast furnace is used to fuse,or melt,iron ore with coke to make pig iron.It also used to make iron from ironore.Fans blow air under pressure into the furnace.This makes the fireextremely hot.Electric furnaces are widely used.Metalworkers ofen needtempe

15、ratures ranging from 1830 to 2800 35000 F to 5000 F.日ectric furnace can produce these temperatures.There are threemain types of electric furnaces.In arc furnaces,heat comes from anelectric arc formed between carbon electrodes.A resistance furnacesworks like a bread toaster.A resistance furnace produ

16、ces heat bypassing an electric current through a substance.The substance,inresisting the electric current,becomes vey hot.An induction furnacesends an alternating current through a conductor.Atomic furnaces or nuclear reactors are designed to producepower by nuclear fission.Their fuel is usually ura

17、nium or plutonium.Solar furnaces produce temperatures of 4400 8000 F orhigher.In a solar furnace,a certain group of mirrors focuses the sunsrays to a specific spot in an oven.熔炉为封闭结构，燃料在其中燃烧时产生的热量。通常是由金属或砖砌成，或其他耐火材料砌成。炉的设计所使用的燃料，产生最大的量的热量。它们也被设计以直接供热的形式。用于取暖，或者用来烧开水产生蒸汽，或加热的各种物质。大约有2大类熔炉。第一类用于家庭取暖的火

18、炉。暖空气的熔炉可以燃烧多种燃料，如煤，焦炭，天然气或石油。这些燃料通过将空气加热而工作。家用炉子使用时必须小心。经常清洁保持其工作效率。同时有于防火，所有炉，烟囱和通风管道应该是每年进行维修一次。炉子连接处的密封接头应定期检查。第二类炉子为工业用炉，主要用于金属加热，制造蒸汽。它们也可以用来生产水泥，玻璃，砖，钢，以及许多其他材料。工业炉产生极高的温度，所使用的燃料多为煤或焦炭为燃料。也有使用天然气、油或电力。高炉是一种工业炉子。高炉炉体为锥形，由砖，混凝土和钢组成。高炉用于将铁矿石融化提炼生铁。压力风机将空气吹入高炉，提高炉温。电炉炼钢被广泛使用。金属制造工人的奥芬需要的温度范围从1830

19、C至28003500叩到5000。日。电炉可以达到这些温度。有三种主要类型的电炉。电弧炉是利用碳电极之间产生的电弧提供热量。而电阻炉的工作原理就像烤箱，其热量的产生是电阻材料通电流后产生高温实现的，电磁感应炉则是通过导体产生交变电流提供热量。原子炉或核反应炉由核裂变反应产生动力，他们使用的燃料通常为铀或钵。太阳能炉产生的温度为44008000平 或更高。在太阳能炉内设有许多镜子，可将太阳光线的热量聚焦在烘箱中的一个特定的区域。Questions:whats a furnace?2 Why electric furnace are widely used?3 Whats fuel for ind

20、ustrial furnaces?问题：1,什么是一个炉?2,为什么电炉被广泛采用？3,什么是工业炉的燃料吗？Unit 3 WELDING AND CUTTINGWelding is a means of joining similar metals by melting them,together so that they fuse(blend together),and then allowing thefused metal parts to harden.Welding involves very high temperatures.The temperature is often p

21、roduced by jets of burning gases.Oxygenand acetylene are often used,producing an oxyacetylene flame.Another flame that can be used is the oxyhydrogen flame.The flame heats the metal parts to be joined until the surfacesbecome molten metal and fuse together.Additional metal may beadded to the joint b

22、y melting wires or rods.The extra metal is addedand built up around the parts to make a solid joint.There are many different kinds of welding.Electric arc weldinguses a heavy current of electricity passed between electrodes.Thiskind of welding is often used in automatic welding machines.In atomichyd

23、rogen welding a stream of hydrogen gas is passed between twotungsten electrodes and an electric arc is struck between theelectrodes.Atomic hydrogen welding is used for high-quality alloysteels.Other kind of welding use beams of electrons,intense beams oflaser light,and streams of gas so hot that the

24、y become plasmas.Welding is an extremely important process in engineering.Itmany be used to join metal pipes,to fix the parts of bridges tightlytogether;and to construct the metal frames of buildings.It is also usedin shipbuilding and in the aircraft industry.Using rivets or nuts andbolts to join pa

25、rts in a structure adds weight to the structure.This isone instance in which welding is better than the other ways of joiningparts,because it dose not add as much weight.Large metal structurescan now be made by joining smaller pieces together on the spot.Inthe past it was necessary to cast large amo

26、unts of metal in molds.Cutting through metals by means of concentrated,very hotflames is widely used in heavy industry.Sheet of steel or other metalcan be shapped with such cutting flames.Thermal cutting is oftenused in the shipbuilding industry and in structural engineering.Acutting torch is used.T

27、his heats the steel to a point at which it is readyto ignite.A jet of oxygen is then passed through the center of theflame,and then the iron in the steel actually burns into iron oxide.Theburnt metal sprays from the other side of the cut in showers of sparks.This method can only be used on steel tha

28、t dose not containmuch chromium.Steel that contains a high proportion of chromiumforms oxides,which burn at a much higher temperature.To counteractthis,powdered iron may be blown in with the jet of oxygen.Thislowers the melting point of the waste metal or slag.Thermal cuttingcan be performed automat

29、ically or by hand.焊接是将金属熔化连接在一起的方法。焊接时将金属熔化（相互熔合），然后熔化的部分冷却变硬（从而成为一体）。焊接在高温下进行，通常是燃烧的气体产生的高温。常用气体为氧气和乙快，产生氧快焰；另一种火焰为氢氧焰。火焰将金属连接部分加热直至熔化，熔合在一起，也可以增加金属焊丝或焊条，这样可使焊接处更加牢固。焊接方法多种，电弧焊采用电极间产生的大电流，应用于自动焊接机上，氢原子焊接的原理是利用氢气流经鸨电极在电极间激发电弧。该种方式应用高质量合金钢焊接，其他的焊接方法采用电极束、激光束以及高热称为等离子体的气流来进行。焊接是工程机械上极为重要的加工工序。可用于连接金属管

30、线，紧固桥梁各组件，以及构造建筑物的框架，也应用于造船业和航空业。采用抑钉、螺钉、螺母连接会增加结构件重量，在这一点上，焊接由于其他连接方法。大的金属结构件可现场用小的部件组装。过去需要大规模铸造金属来制造。金属切割采用火焰切割，重工业应用十分广泛，钢板或其他金属板可用此方法切割成型，热切割常应用于造船业和结构工程上。采用火焰切割机进行切割，首先将钢加热至高温，然后向火焰中心吹氧，钢中的铁元素氧化，切割时产生大量的火花。钢中如果含有过多倍则不宜采用火焰切割，因为铝氧化物的熔点很高。为解决这个问题，吹氧时需要加入铁粉，来降低熔点。火焰切割可自动或人工进行操作。Question:1、Whats w

31、elding?2 Whats cutting?问题：1,什么是焊接？2,什么是切割？Unit 4 Installation1.UnpackingIn unpacking,the shipping list must be first examined to ensurethe proper configuration of the required system.All the parts,attachments and spare parts of the shipped system have then to bechecked item by item according to the

32、shipping list for their types,quantities and external appearances to exclude confusions,mistakepacking,shortages and damages.The control Unit Classis must besubject to a further inspection for the correct types,good mechanicalfastening and reliable electrical connections of all its components,such a

33、s PCBs switches and keys,transformers and so forth.2.MountingMount the Control Unit Classis safely on the machine tool at aposition convenient to operator.A cantilever bracket shown in Fig.3-1might be quire helpful.In some systems,the driver circuitry with thepower transformer are packed in a separa

34、te chassis,it should be fixedsecurely also.Mount the stepper motors to the feed mechanism ofmachine tool.3.Powering-OnConnect the motor drives,the stepper motors and the mainpower supply to the Control Unit classis according to the Assemblyand Wiring Diagram.Before the main source is turned on,the L

35、oadButton for the power amplifier must be set OFF”.Turn on the mainsource switch,and the Control Unit is now put in work.At this instant,the ventilator blowers must work properly,as the blowers prohibit theControl Unit work without the forced ventilation.1、拆箱在拆箱的过程中，必须先检查运输清单，以保证系统所需的的构件齐全。然后运输系统所有的

36、零件，附件和备件必须依照备件清单，逐一检查他们的型号、数量、外形特征一排除混乱的、错装的、缺损等情况。控制部件底盘必须进行进一步检查，包括所有元件的正确型号、完好的机械固定、导线连接，例如印刷电路板的开关、调节器、变压器、等等。2、安装安全地将控制部件底盘安装在机床上易操作的部分。图三所示悬臂支架可能会有帮助。在某些系统中，带变压器的驾驶员电路安装在单独的底盘上，它也需要固定安全。安装步进电动机供给机床的机械装置。3、供给动力依照装配及接线图接通电动驱动器、步进电动机及主电源，供给控制部件底盘在主电源打开前，功率放大器负债按钮必须为“关”。打开主电源开关时控制部件将开始工作。在这一刻，通风机、

37、送风机必须很好地工作，因为没有强制通风，送风机将阻止控制部件的工作。Exercise:1.Dsecribe the step of Installation2.Translsting:A:In unpacking,the shipping list must be first examined to ensurethe proper configuration of the required system.B:Before the main source is turned on,the Load Button for thepower amplifier must be set OFF.练习

38、:1 o的安装Dsecribe步骤2。Translsting：A：在拆包，发货清单必须先检查，以确保正确的配置所需的系统。B：开启之前的主要来源，按钮功率放大器的负载必须设置为“OFF”。Unit 5 Machine ElementsMachine elements are elementary parts used as building blocksfor the construction of most devices,apparatus,and machinery.Thegradual development of these building blocks,following the

39、 inventionof the roller or wheel and arm or lever in ancient times,brought aboutthe industrial Revolution,starting with the assembly of James Wattsengine for harnessing the force of steam and proceeding into theadvanced mechanization of present automatic control.The most common example of a machine

40、element is a gear,which,fundamentally,is a combination of the wheel and the lever to from atoothed wheel as illustrated.The rotation of this gear on a hub of shaftdrives other gears which may rotate faster or slower;depending uponthe number of teeth on the basic wheel.The material from which thegear

41、 is made establishes its strength,and the hardness of its surfacedetermines its resistance to wear.Knowledge of the forces on the gearmakes possible the determination of its size.Change in its shape allowmodification in its use.These applications,as in most machine elements,have developedinto many s

42、tandard forms,such as spur;bevel,helical,and worm gears.Each of these forms has required the development of a specialtechnology for its production and use.Other fundamental machineelements have evolved from wheels and levers.A wheel must have ashaft on which it may rotate.The wheel is fastened to th

43、e shaft with akey,and the shaft is joined to other shafts with couplings.The shaftmust test in bearings,such as journal bearing,ball bearings,or rollerbearings.The shaft may be starred by a clutch or stopped with a brake.It may be turned by pulley with a flat belt,a V belt,or C chainconnecting it to

44、 a pulley on a second shaft.The supporting structuremay be assembled with bolts or rivets or by welding.Properapplication of the materials employed.In the design,calculations must accommodate the forces to thematerials in the simplest construction.Other machine elements havebeen evolved whose applic

45、ations are more specific in construction.Machine parts which are commonly used have been developed intostandardized designs.Manufacturing specialists have concentratedupon development of standard elements and have mass-producedthese parts with a high degree of perfection at reduced cost.机元素是基本的部分，大部

46、分的设备，仪器，机械的建设作为构建块。的逐步发展，这些构建块，以下的短或轮和手臂或杠杆在古代的发明，带来了关于工业革命，开始组装詹姆斯瓦特的发动机利用蒸汽和诉讼的力量到的先进的机械化目前的自动控制。一台机器元件的最常见的例子是一个齿轮，其中，从根本上说，是从所示的带齿的轮的组合和车轮的杆。该齿轮的轴的轮毂上的旋转驱动器等的可旋转的齿轮更快或更慢，取决于齿的数目上的基本轮。由齿轮的材料，从建立其强度，和其表面上的硬度决定其耐磨性。知识的力量上的齿轮，可以测定其大小。变更其形状，在其使用允许修改。这些应用程序，在大多数机器元素，已经发展成为许多标准的形式，如正齿轮，伞齿轮，斜齿轮，蜗轮蜗杆。这些形

47、式中的每一个已经需要一种特殊的技术的发展，其生产和使用。其他基本的机械元件已经从轮毂和杠杆。一种车轮必须有一个轴，在其上，它可以旋转。轮用键固定在轴上，与轴连接到其他的联接器的轴。的轴的轴承，如轴颈轴承，球轴承或滚子轴承必须测试。可能会出演轴通过离合器或制动停了下来。与平皮带，V形皮带，或C链，将其连接到一个滑轮上的第二轴，它可转动皮带轮。可组装的支撑结构，用螺栓或抑钉，或通过焊接。正确应用的材料。在设计中，计算必须容纳的力量，在最简单的施工的材料。其他机械元件上发展起来的，其应用更具体的建设。这是常用的机械零件已经发展成为标准化的设计。制造专家已经开发标准元素后，浓缩，并具有大规模生产的这些

48、部件具有高的完善程度，在降低成本的Translating:A:Machine elements are elementary parts used as buildingblocks for the construction of most devices,apparatus,and machinery.B:Manufacturing specialists have concentrated upondevelopment of standard elements and have mass-produced theseparts with a high degree of perfecti

49、on at reduced cost.翻译：A：机械零件作为构建块的建设大部分的设备，仪器，机械的基本部分。B：制造专家已经开发标准元素后，浓缩，并已大规模生产这些部件具有高的完善程度在降低成本的。Unit 6 Introduction to PLCA PLC(Programmable Logic Controller)is a device that wasinvented to replace the necessary sequential reply circuits formachine control.The PLC work by looking at its inputs an

50、d dependingupon their state,turning on/off its outputs.The user enters a program,usually via software,which gives the desired results.PLCs are used inmany“real word“applications.If there is an industry present,chancesare good that there is a PLC present.If you are involved in machining,packaging,mat