ChaTwoUnitThree上课定.ppt

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1、Chapter TwoUnit Three Shortwave Communication,New Words and Expressions,wireless wails adj.用无线电波传送的medium mi:dim adj.中等的；平均的；convenience kn vi:nins n.方便，便利；AM ei em amplitude modulation 调幅 mplitju:d mdjleinimplement implimnt vt.实施，执行；使生效；layer lei n.层，层次；放置者，计划者；atmosphere tmsfi(r)n.大气，空气；大气层；风格，基调；

2、气氛verification verifi kein n.证明；证实；核实,New Words and Expressions,ionosphere ai nsfi n.电离层skywave skaiweiv n.天波groundwave randweiv n.地波vacuum vkjm n.真空，空白；空间；amateur mt(r)n.业余爱好者；外行；inevitable in evitbl adj.不可避免的；必然发生的；,Text,Medium wave was one of wireless radio used early by human,which covered broad

3、cast GPS,telecommunication and so on.,中波是人们较早利用的无线电波段之一，主要用于广播、导航和通信等方面。,Shortwave across ocean was transmitted firstly in 1921.Instead of famous expert,the pioneer was an amateur.,1921年，人类首次实现了短波跨越海洋的传播。开创者并不是赫赫有名的专家，而是名不见经传的业余无线电爱好者。,there was an electronic particle layer in the atmosphere.,大气层中有一

4、个带电粒子层。,This suppose could not be valued enough in this period.,这个假设在这一段时间没有得到人们足够的重视。,Radio wave transmitted by shortwave,named shortwave communication.Sky wave was transmitted by ionospheres reflection.,用短波进行的无线电通信，称为短波通信。天波传播正是靠电离层的反射进行的。,Text,In Mar.1899,Marconi made experiment successful,which

5、wireless radio could be transmitted across the English Channel 45,000 meters wide.At that time,it was medium wave that Marconi used,which was radio signal with length between 1000 and 100 meters(frequency between 300一3000khz).Medium wave was one of wireless radio used early by human,which covered br

6、oadcast GPS,telecommunication and so on.1899年3月，马可尼成功地进行了使无线电波越过45千米宽的英吉利海峡进行传送的实验。当时，马可尼所用的是中波，即波长为1000100米（相应频率为3003000千赫）的无线电波。中波是人们较早利用的无线电波段之一，主要用于广播、导航和通信等方面。,Shortwave across ocean was transmitted firstly in 1921.Instead of famous expert,the pioneer was an amateur.Shortwave is radio between 1

7、00一10 meters(frequency between 3一30khz).Because of long-distance transmission,cheapness and convenience,shortwave exceeded AM in the telecommunication and broadcast.,1921年，人类首次实现了短波跨越海洋的传播。开创者并不是赫赫有名的专家，而是名不见经传的业余无线电爱好者。短波是波长10010米(相应频率为330兆赫)的无线电波。由于短波传播距离远、经济方便，在通信和广播领域，短波传播很快超过了中波传播。,Transmitting

8、 to 3000 kilometers,Marconi implemented transmission,radio across ocean in Dec.1901.Many scientists begin to reflect from then on,that it was impossible for telecommunication across ocean,because longer radio wave was transmitted on earth,weaker signal was,according to traditional theory.However,how

9、 could this radio wave be transmitted from Britain to Newfoundland in North America 3000 km far.,1901年12月，马可尼实现了无线电波的越洋传播，传送距离达3000千米。这促使许多科学家思考这样的问题：按照传统理论，无线电波沿地面传输时会随距离增加而急剧衰减，越洋通信是不可能实现的，这一次无线电波怎么会从英国传播到3000千米之外北美的纽芬兰呢？,In order to explain it,British electric engineer Heaviside and American thel

10、ecom engineer Kennelly supposed bravely that,Marconis radio wave could travel deviously around the planet,the reason was that,there was an electronic particle layer in the atmosphere,which could exist by sun ultraviolet playing ionization with air in the atmosphere.,为了解释上述现象，英国电气工程师亥维赛及美国的通信工程师肯内利(生

11、于印度)大胆地做出猜测：马可尼的无线电信号所以能绕地球弯曲传播，可能是大气层有带电粒子层的缘故，而这个带电粒子层，是由于太阳紫外线对大气层中空气的电离作用而产生的。,In the 1919,British physicist and radar expert Walson Watt proofed indirectly on theory that,there was a conductive layer in the atmosphere in the research of radio waves transmission in the vertical radiation device.

12、Because of lacking experimental verification,this suppose by Heaviside and Kennelly could not be valued enough in this period.,1919年，在研究无线电波在垂直辐射器中的传播时，英国物理学家、雷达专家沃森瓦特，从理论上间接证明了大气层上空存在一个导电的气层。由于没有经过实验验证，亥维赛及肯内利有关带电粒子层反射电磁波的假设，在这一段时间没有得到人们足够的重视。,British famous physicist Appleton found in 1926 the App

13、leton ionosphere(F-ionosphere),who won Nobel Prize in 1947 because of this contribution.1926年，英国著名物理学家阿普尔顿发现了阿普尔顿电离层(F电离层)。由于这一突出贡献，1947年他荣获诺贝尔物理学奖。,1930,British physicist Walson Watt named this conductive particle layer on the atmosphere as ionosphere formally.1930年，英国物理学家沃森瓦特正式把存在于高空大气层中的带电粒子层命名为“

14、电离层”。,Radio wave transmitted by shortwave,named shortwave communication,was transmitting through skywave and groundwave.Skywave was transmitted by ionospheres reflection.For less depletion,little power and light cost,it can play communication and broadcast in long distance.Shortwave was a major meth

15、od in the international broadcast,which was also usual wave band in the modern amateur radio telecommunication.,用短波进行的无线电通信，称为短波通信，它主要靠天波和地波两种方式传播。天波传播正是靠电离层的反射进行的，它的传播衰耗小，因此用较小的功率、较低的成本，就能进行远距离的通信和广播。短波广播至今仍是国际广播的主要手段，短波波段也是现代业余无线电通信常用的波段。,The former Soviet Union built up a shortwave broadcast stat

16、ion with 120kilowatt in 1938,which had the biggest power in the world at that time.,1938年，前苏联建成了一个功率为120千瓦的短波无线电广播电台PB?6，它是当时世界上功率最大的一个电台。,In fact,from American chemist Lan Mauer invented vacuum electronic tube in 1912,which was put into practice.And set up in 1921,Radio Corporation of America put r

17、elated tubes and radio components together,which authorized by Marconi,Bell Telephone,and General Electric Corporations.So these products began to be manufactured in massive scale,and electronics became an independent industry.Not only development of radio broadcast and telecommunication industry wa

18、s promoted,but also huge energy was brought into radio amateurs activities.In this way,it was inevitable for them to find shortwave.,20年代问世的短波通信，改变了无线电通信发展的历史进程。它起源于无线电业余爱好者的发现，这似乎有点偶然。实际上，自从1912年美国化学家兰茂尔研制出高真空电子管后，电子管便进入了实用阶段，加上1921年美国无线电公司成立，它把原属于“马可尼”、“贝尔电话”、“通用电气”等公司有关电子管及无线电元器件的专利统统集中起来，使上述产品的制

19、造进入大规模工业化生产的阶段，电子工业开始形成一门独立的产业。这些不仅推动了无线电广播和通信事业的迅速发展，还给无线电业余爱好者的活动带来了巨大的活力，所以，由无线电业余爱好者发现短波通信，也带有某种必然性。,1 Choose the correct item in the following sentences.(1)Which was used early by human,which covered broadcast GPS,telecommunication and so on?A.wireless radio B.shortwave C.medium D.long wave(2)W

20、hat is the advantages of shortwave exceeded AM in the telecommunication and broadcast?A.long distance transmission.B.cheapnessC.convenience D.all of them(3)Why is it impossible for telecommunication across ocean?A.because longer radio wave was transmitted on earth,weaker signal was,according to trad

21、itional theory.B.many scientists said.C.ocean is more difficult to transmit than earth.D.not mentioned.,Exercises,the more the more句型,1.“the more.,the more.”句型常表示“越就越”,是一个复合句,其中前面的句子是状语从句,后面的句子是主句。the用在形容词或副词的比较级前,more代表形容词或副词的比较级。例如:The more he gets,the more he wants.他越来越贪婪。The more she learns,the

22、more she wants to learn.她越学越想学。,the more the more句型,2.“the more.,the more.”句型,主从句的时态常用一般现在时或一般过去时。例如:The higher the ground is,the thinner air becomes.离地面越高,空气就越稀薄。The harder he worked,the more he got.他工作越努力,得到的就越多。,the more the more句型,3.若主句的谓语动词用一般将来时,从句的谓语动词要用一般现在时表示将来。例如:The harder you work,the gr

23、eater progress you will make.你越用功,进步就越大。The longer the war lasts,the more the people there will suffer.战争持续得越久,那里的人们受难就越多。,the more the more句型,4.若比较级作表语且不位于句首时,可以不用the。例如:When we are more in danger,we should be braver.越是危险,我们越应勇敢。5.在这种句型中,主句在程度上随着从句变化而变化,常把被强调部分提前。例如:The faster you run,the better it

24、 will be.你跑得越快越好。,the more the more句型,6.这种句型的特点是前后都可以有所省略。特别是谚语、俗语,只要意义明确,越简练越好。例如:The more,the better.多多益善。The sooner,the better.越早越好。,(4)Why could Marconis radio could travel deviously around the planet?A.British electric engineer Heaviside and American thelecom engineer Kennelly proofed that.B.Th

25、ere was an electronic particle layer in the atmosphere.C.Marconi proofed thatD.None of them(5)Who built up a shortwave broadcast station with 120 kilowatt in 1938?A.China B.America C.The former Soviet Union D.Japan,2.Translate following sentences from English into Chinese?(1)In Mar.1899,Marconi made

26、 experiment successful,which wireless radio could be transmitted across the English Channel 45,000 meters wide.(2)In the 1919,British physicist and radar expert Walson Watt proofed indirectly on theory that,there was a conductive layer in the atmosphere in the research of radio waves transmission in

27、 the vertical radiation device.(3)In fact,from American chemist Lan Mauer invented vacuum electronic tube in 1912,which was put into practice.,Talking Face to Face,Part Three,A:I have intended to go to the library to find some information（资料、信息）for my graduate paper（毕业论文）.But it has closed now.B:Why

28、 not search（查找）the information on the Internet?In modern（现代的）society（社会）,we should try to utilize（使用）the high technology.A:Where can I find those information?B:I recommend（建议）you.It is a Chinese versatile（多功能）site（网站）.A:Oh,could you introduce（介绍）some other information related（与有关）to the website（网站）?B:There are a lot of famous websites in our daily（日常的）life.For example:.It is a very famous searcher.,it is an internet shopping website where you can buy various（各种）of things by it.,