雅思阅读考试模拟试练习题与答案解析doc.docx
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雅思阅读考试模拟试练习题与答案解析doc.docx
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雅思阅读考试模拟试练习题与答案解析doc
2019年雅思阅读考试模拟试练习题及答案解析
Timetocoolit
FromTheEconomistprintedition
1REFRIGERATORSaretheepitomeofclunkytechnology:
solid,reliableandjustalittlebitdull.Theyhavenotchangedmuchoverthepastcentury,butthentheyhavenotneededto.Theyarebasedonarobustandeffectiveidea--drawheatfromthethingyouwanttocoolbyevaporatingaliquidnexttoit,andthendumpthatheatbypumpingthevapourelsewhereandcondensingit.Thismethodofpumpingheatfromoneplacetoanotherservedmankindwellwhenrefrigerators'mainjobswerepreservingfoodand,asairconditioners,coolingbuildings.Today'shigh-techworld,however,demandshigh-techrefrigeration.Heatpumpsarenolongeruptothejob.Thesearchisonforsomethingtoreplacethem.
2Onesetofcandidatesareknownasparaelectricmaterials.Theseactlikebatterieswhentheyundergoatemperaturechange:
attachelectrodestothemandtheygenerateacurrent.Thiseffectisusedininfra-redcameras.Anarrayoftinypiecesofparaelectricmaterialcansensetheheatradiatedby,forexample,aperson,andthepatternofthearray'selectricaloutputscanthenbeusedtoconstructanimage.Butuntilrecentlynoonehadbotheredmuchwiththeinverseofthisprocess.Thatinverseexists,however.Applyan
appropriatecurrenttoaparaelectricmaterialanditwillcooldown.
3SomeonewhoislookingatthisinverseeffectisAlexMischenko,ofCambridgeUniversity.Usingcommerciallyavailableparaelectricfilm,heandhiscolleagueshavegeneratedtemperaturedropsfivetimesbiggerthananypreviouslyrecorded.Thatmaybeenoughtochangethephenomenonfromalaboratorycuriositytosomethingwithcommercialapplications.
4Astowhatthoseapplicationsmightbe,DrMischenkoisstillalittlehazy.Hehas,nevertheless,setupacompanytopursuethem.Heforeseesputtinghisdiscoverytouseinmoreefficientdomesticfridgesandairconditioners.Therealmoney,though,maybeincoolingcomputers.
5Gadgetscontainingmicroprocessorshavebeengettinghotterforalongtime.OneconsequenceofMoore'sLaw,whichdescribesthedoublingofthenumberoftransistorsonachipevery18months,isthattheamountofheatproduceddoublesaswell.Infact,itmorethandoubles,becausebesidesincreasinginnumber,thecomponentsaregettingfaster.Heatisreleasedeverytimealogicaloperationisperformedinsideamicroprocessor,sothefastertheprocessoris,themoreheatitgenerates.Doublingthefrequencyquadruplestheheatoutput.Andthefrequencyhasdoubledalot.ThefirstPentiumchipssoldbyDrMoore'scompany,Intel,in1993,ranat60mcycles
asecond.ThePentium4--thelast"single-core"desktopprocessor--clockedup3.2billioncyclesasecond.
6Disposingofthisheatisabigobstructiontofurtherminiaturisationandhigherspeeds.Theinnardsofadesktop
computercommonlyhit80℃.At85℃,theystopworking.Tweakingtheprocessor'sheatsinks(copperoraluminiumboxesdesignedtoradiateheataway)hasreacheditslimit.Sohastweakingthefansthatcirculateairoverthoseheatsinks.Andtheideaofshiftingfromsingle-coreprocessorstosystemsthatdividedprocessingpowerbetweenfirsttwo,andthenfour,subunits,inordertospreadthethermalload,alsoseemstohavetheendoftheroadinsight.
7Onewayoutofthismaybeasecondcuriousphysicalphenomenon,thethermoelectriceffect.Likeparaelectricmaterials,thisgenerateselectricityfromaheatsourceandproducescoolingfromanelectricalsource.Unlikeparaelectrics,asignificantbodyofresearchersisalreadyworkingonit.
8Thetricktoagoodthermoelectricmaterialisacrystalstructureinwhichelectronscanflowfreely,butthepathofphonons--heat-carryingvibrationsthatarelargerthanelectrons--isconstantlyinterrupted.Inpractice,thistrickishardtopulloff,andthermoelectricmaterialsarethuslessefficientthanparaelectricones(or,atleast,thanthoseexaminedbyDrMischenko).Nevertheless,RamaVenkatasubramanian,ofNextremeThermalSolutionsinNorth
Carolina,claimstohavemadethermoelectricrefrigeratorsthatcansitonthebackofcomputerchipsandcoolhotspotsby
10℃.AliShakouri,oftheUniversityofCalifornia,SantaCruz,sayshisareevensmaller--sosmallthattheycangoinsidethechip.
9Thelastwordincomputercooling,though,maygotoasystemevenlesstechythanaheatpump--aminiatureversionofacarradiator.LastyearApplelaunchedapersonalcomputerthatiscooledbyliquidthatispumpedthroughlittlechannelsintheprocessor,andthencetoaradiator,whereitgivesupitsheattotheatmosphere.Toimproveonthis,IBM'sresearchlaboratoryinZurichisexperimentingwithtinyjetsthatstirtheliquidupandthusmakesureallofiteventuallytouchestheoutsideofthechannel--thepartwheretheheatexchangetakesplace.Inthefuture,therefore,acombinationofmicrochannelsandeitherthermoelectricsorparaelectricsmightcoolcomputers.Theold,asitwere,handinhandwiththenew.
(830words)
Questions1-5
Completeeachofthefollowingstatementswiththescientistorcompanynamefromtheboxbelow.
WritetheappropriatelettersA-Finboxes1-5onyouranswersheet.
A.Apple
B.IBM
C.Intel
D.AlexMischenko
E.AliShakouri
F.RamaVenkatasubramanian
1....andhisresearchgroupuseparaelectricfilmavailablefromthemarkettoproducecooling.
2....soldmicroprocessorsrunningat60mcyclesasecondin1993.
3....saysthathehasmaderefrigeratorswhichcancool
thehotspotsofcomputerchipsby10℃.
4....claimstohavemadearefrigeratorsmallenoughtobebuiltintoacomputerchip.
5....attemptstoproducebettercoolinginpersonalcomputersbystirringupliquidwithtinyjetstomakesuremaximumheatexchange.
Questions6-9
Dothefollowingstatementsagreewiththeinformationgiveninthereadingpassage?
Inboxes6-9onyouranswersheetwrite
TRUEifthestatementistrueaccordingtothepassage
FALSEifthestatementisfalseaccordingtothepassage
NOTGIVENiftheinformationisnotgiveninthepassage
6.Paraelectricmaterialscangenerateacurrentwhenelectrodesareattachedtothem.
7.Dr.Mischenkohassuccessfullyappliedhislaboratorydiscoverytomanufacturingmoreefficientreferigerators.
8.Doublingthefrequencyoflogicaloperationsinsideamicroprocessordoublestheheatoutput.
9.IBMwillachievebettercomputercoolingbycombiningmicrochannelswithparaelectrics.
Question10
ChoosetheappropriatelettersA-Dandwritetheminbox10onyouranswersheet.
10.Whichmethodofdisposingheatincomputersmayhaveabrightprospect?
A.Tweakingtheprocessors?
heatsinks.
B.Tweakingthefansthatcirculateairovertheprocessor
抯heatsinks.
C.Shiftingfromsingle-coreprocessorstosystemsofsubunits.
D.Noneoftheabove.
Questions11-14
Completethenotesbelow.
ChooseonesuitablewordfromtheReadingPassageaboveforeachanswer.
Writeyouranswersinboxes11-14onyouranswersheet.
Traditionalrefrigeratorsuse...11...pumpstodrop
temperature.Atpresent,scientistsaresearchingforothermethodstoproducerefrigeration,especiallyincomputermicroprocessors....12...materialshavebeentriedtogenerate
temperaturedropsfivetimesbiggerthananypreviouslyrecorded....13...effecthasalsobeenadoptedbymanyresearcherstocoolhotspotsincomputers.Aminiatureversionofacar...14...mayalsobeasystemtorealizeidealcomputercoolinginthefuture.
KeyandExplanations:
1.D
SeeParagraph3:
...AlexMischenko,ofCambridgeUniversity.Usingcommerciallyavailableparaelectricfilm,heandhiscolleagueshavegeneratedtemperaturedrops...
2.C
SeeParagraph5:
ThefirstPentiumchipssoldbyDrMoore'scompany,Intel,in1993,ranat60mcyclesasecond.
3.F
SeeParagraph8:
...RamaVenkatasubramanian,ofNextremeThermalSolutionsinNorthCarolina,claimstohavemadethermoelectricrefrigeratorsthatcansitonthebackof
computerchipsandcoolhotspotsby10℃.
4.E
SeeParagraph8:
AliShakouri,oftheUniversityof
California,SantaCruz,sayshisareevensmaller梥osmallthattheycangoinsidethechip.
5.B
SeeParagraph9:
Toimproveonthis,IBM'sresearchlaboratoryinZurichisexperimentingwithtinyjetsthatstirtheliquidupandthusmakesureallofiteventuallytouchestheoutsideofthechannel--thepartwheretheheatexchangetakesplace.
6.TRUE
SeeParagraph2:
...paraelectricmaterials.Theseactlike
batterieswhentheyundergoatemperaturechange:
attachelectrodestothemandtheygenerateacurrent.
7.FALSE
SeeParagraph3(Thatmaybeenoughtochangethephenomenonfromalaboratorycuriositytosomethingwithcommercialapplications.)andParagraph4(Astowhatthose
applicationsmightbe,DrMischenkoisstillalittlehazy.Hehas,nevertheless,setupacompanytopursuethem.Heforeseesputtinghisdiscoverytouseinmoreefficientdomesticfridges?
8.FALSE
SeeParagraph5:
Heatisreleasedeverytimealogicaloperationisperformedinsideamicroprocessor,sothefastertheprocessoris,themoreheatitgenerates.Doublingthefrequencyquadruplestheheatoutput.
9.NOTGIVEN
SeeParagraph9:
Inthefuture,therefore,acombinationofmicrochannelsandeitherthermoelectricsorparaelectricsmightcoolcomputers.
10.D
SeeParagraph6:
Tweakingtheprocessor'sheat
sinks?
hasreacheditslimit.Sohastweakingthefansthat
circulateairoverthoseheatsinks.Andtheideaofshifting
fromsingle-coreprocessorstosystems?
alsoseemstohave
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