[电子信息工程][课件][Unit05]

UnitFive1.ELECTROMAGNETICINDUCTION电磁感应2.BASICPRINCIPLESOFMOTORS电动机基本原理3.BARCODING条形码1.ELECTROMAGNETICINDUCTION电磁感应1.Words：barn.条,棍,酒吧v.禁止,阻挡motionn.运动,移动v.运动motiven.动机,目的a.运动的,发动的motivationn.动机move-mentn.运动,动作,乐章deficitn.缺少,亏损potentialdifference位差,势差,电势差1.SentenceIfthedirectionofthemotionissuchthatacomponentoftheforceontheelectronsisparalleltotheconductor,theelectronswillmovealongtheconductor.如运动方向使作用在电子上的一部分力平行于导体,电子将沿着导体运动.Theelectronswillmoveuntiltheforcesduetothemotionoftheconductorthroughthemagneticfieldarebalancedbyelectrostaticforcesthatarisebecauseelectronscollectatoneendoftheconductor,leavingadeficitofelectronsattheother.电子的运动直到它受到由于导体切割磁场运动的力和静电力平衡为止,这种静电力是因为电子聚集在导线的一端,而另一端缺少电子而引起的.Questions1.Whathappensifaconductingbarmovesthroughamagneticfield?2.Asfarasthedirectionsofthemotionisconcerned,whatwilltheelectronsdowhenacomponentoftheforceontheelectronsisparalleltotheconductor?3.Whenwillelectronsstopmoving?4.Whathappenstotheelectronsifthemotionstops?2.WordsEq.=equation方程,相等,平衡righta.直的,垂直的,右边的n.垂直,右边velocityn.速度,速率,周转率perpendiculara.垂直的webern.韦伯coulombn.库仑newtonn.牛顿Question1.Whatdoesthesymbolrepresentintheequation?sinBqVF3.Wordsintensityn.强度,亮度densityn.密度,稠度rigidityn.硬度magnituden.大小,数量,广大potentialn.电压,潜能,潜力a.潜在的,位的,势的gradientn.梯度holdv.成立,有效,占有,支持,保留3.SentenceTheelectricfieldintensityEduetothisforceisgiveninmagnitudeanddirectionbytheforceperunitpositivecharge.电场强度取决于单位电荷上所受力的大小和方向.1.WhatistheelectricfieldintensityE?Question4.Wordsstationarya.静止的emf=electromotiveforceinsense就…意义而言,inasense在某种意义上4.SentenceHowever,ifthetwoendsoftherodwereconnectedbyawirethatmovethroughthefieldwiththerod,therewouldbeanemfinducedinthewirethatwouldbeequaltothatintherodandoppositeinsenseinthecircuit.但是,如导体杆的两端和一根导线连接,导线和导体一起移动并通过磁场,导线中也会感应出一个与杆中大小相等的电动势并且在某种意义上与电路中的电动势反向.1.Howistheelectromotiveforcemeasured?2.Whatwouldbeinducedinthewireifthetwoendsoftherodwereconnectedbyawirethatmovedthroughthefieldwiththerod?Questions2.BASICPRINCIPLESOFMOTORS1.Wordsstatorn.定子rotorn.转子rotatev.使旋转rotarya.旋转的commutatorn.换向器assemblyn.集合,装配,汇编assemblev.汇编,集合framen.框架电动机基本原理1.Questionwhatisthefunctionofamotor?2.Wordscompressionn.压缩splitringsn.缝隙环clockwise顺时针;counterclockwise逆时针Whyisnocurrentflowingthroughtheconductorsinfig.5-1?2.SentenceThecircularmagneticfieldaroundtheconductorscausesacompressionofthemainmagneticfieldatpointsAandB.导体周围的环形电磁场引起主磁场A/B两点压缩.MotionisproducedawayfrompointsAandB.偏离A/B点的运动由此产生.3.Wordstorquen.转矩3.QuestionWhatdoestheamountoftorqueproducedbyamotordependon?DOEXERCISEA!1.c2.c3.d.4.b.5.b.6.c.7.a.DOEXERCISEB!inattointoin/from/toof/within/forforthroughofDOEXERCISEC!Archaeological考古学的risky冒险的,危险的massive结实的sleeves袖子cogitable可以思考的4.BARCODING1.automaticidentificationtechnology自动识别技术predominanta.卓越的,主要的,统治地位的magneticstripe磁带;smartcards智能卡;opticalcharacterrecognition光学标志识别2.symbology表示法,象征学;retailproducts零售商品UniversalProductCode通用产品码;counterpart副本,对应物;EuropeanArticleNumberingsystem欧洲产品编码体系3.interpret解释,译码;fluctuation强弱,波动,起伏barsandspaces线条和间隙reflection反射4.BARCODING4.incandescent白炽灯infraredLED红外LEDheliumneonlaser氦氖激光器;accommodate适应5.preprint预印制;contrastive对比度;nonsmearing无着色;4.BARCODING2.Themannerinwhichthelinesandspacesarearrangediscalledasymbology,ofwhichthereareseveraldefinedsymbologyes.直线和空隙排列的形式称为表示法,已有几种定义过的表示法..TheEuropeancounterparttotheUPCistheEuropeanArticleNumberingsystemandtheJapanesecounterpartistheJapaneseArticleNumberingsystem.欧洲与UPC对应的码是欧洲产品编码体系,日本对应的是日本产品编码体系.4.BARCODING3.Barcodesarereadorscannedbypassingabeamoflightacrossthecodeandinterpretingthefluctuationsinreflectionofthebeamasitcrossesthebarsandspaces.条形码用下列方法阅读或扫描,把一束光照射在编码上,并使它在线条和空隙间移动,再对反射光强弱译码.4.Somescannersmustcontactthelabeltoread,whileotherscanreadfromadistance,sometimesuptoseveralfeet,somereadersarestationary,whileothersarehandheld.一些扫描器工作时要接触条形码标签,另一些扫描器则不必接触,有时可以离开标签几英尺外工作.4.BARCODING5.Someobjectswouldbedifficulttoprintabarcodedirectlyonduetotheirshapeorsize.Mostpre-printedbarcodelabelsareverifiedforsatisfactoryreadabilitybeforebeingplacedintoservice.有些物品局限于它们的形状尺寸不适合印刷条形码.大多数预制的条形码标签在使用前被证实是十分易读的.TECHNOLOGYARTICALSWhatisRFID?Radiofrequencyidentification,orRFID,isageneric特殊的termfortechnologiesthatuseradiowavestoautomaticallyidentifypeopleorobjects.Thereareseveralmethodsofidentification,butthemostcommonistostoreaserialnumberthatidentifiesapersonorobject,andperhapsotherinformation,onamicrochipthatisattachedtoanantenna(thechipandtheantennatogetherarecalledanRFIDtransponderoranRFIDtag应答器).Theantennaenablesthechiptotransmittheidentificationinformationtoareader.ThereaderconvertstheradiowavesreflectedbackfromtheRFIDtagintodigitalinformationthatcanthenbepassedontocomputersthatcanmakeuseofit.TECHNOLOGYARTICALSHowdoesanRFIDsystemwork?AnRFIDsystemconsistsofatag,whichismadeupofamicrochipwithanantenna,andaninterrogator询问者orreaderwithanantenna.Thereadersendsoutelectromagneticwaves.Thetagantennaistunedtoreceivethesewaves.ApassiveRFIDtagdrawspowerfromfieldcreatedbythereaderandusesittopowerthemicrochip’scircu