四川大学化工考研884复试面试英语题库翻译原文.doc

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1、1.Whenafluidflowsthroughaductoroverasurface,thevelocityoveraplaceatrightanglestothestreamisnotnormallyuniform.Thevariationofvelocitycanbeshownbytheuseofstreamlineswhicharelinessodrawnthatthevelocityvectorisalwaystangentialtothem.Theflowratebetweenanytwostream

2、linesisalwaysthesame.Constantvelocityoveracross-sectionisshownbyequidistantstreamlinesandincreaseinvelocitybycloserspacingofstreamlines.2.Itisfoundtheheattransferrateperunitareaqisdependentonthosephysicalpropertieswhichaffectflowpattern.Thethermalpropertiesof

3、thefluidandthevelocityofflowthefluidoverthesurface,thetemperaturedifferencetandafactordeternmingthenaturalcirculationeffectcausebyexpansionofthefluidonheating.3.Theoildistilledinaverylargesteeltower,thetechnicalnamesofwhichisthefractionatingtower.Thetoweristh

4、irtytofiftymeterstallanditsdiameterisonetothreemeters.Itisdividedintochambers,eachofwhichcontainsalayeroftrays.Thereareholesinthetrays.Thechanbersareatdifferentheights,andtemperatureateachheightisdifferent.4.Agroupofoperationforseparatingthecomponentsofmixtur

5、eisbasedonthetransferofmaterialfromonehomogeneousphasetoanther.Unlikepurelymechanicalseparation,thesemethodsutilizedifferencesinvaporpressureorsolubility,notdensityorparticlesize.Thedrivingforcefortransferisaconoantrationdiffercetooraconcentrationgradient,muc

6、hasatemperaturedifferenceoratemperaturegradientprovidesthedrivingforceheattransfer.5.Thethreemostimportantcharacteristicsofanindividualparticleareitscomposition,itssizeanditsshape.Compositiondeterminesuchpropertiesasdensityandconductivity，providedthattheparti

7、cleiscompletelyuniform.Aparticleshapemayberegularsuchassphericalorcubic,oritmaybeirregularas,forexample,withapieceofbrokenglass.1.homogeneouscatalysisistheindustricaloxoprocessformanufacturingnormaliosobuty(异丁醛)。Ahomogeneouscatalysispressinvolvemorethanonepha

8、se，usuallythecatalystisasolidandthereactantsandproductsareinliquidorgaseousform.2.Whenthevaporsriseintothecoolerpartofthefractionatingtower,theyloseheat,thevaporsriseuntiltheyarejustbelow