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1、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--
2、drawheatfromthethingyouwanttocoolbyevaporatingaliquidnexttoit,andthendumpthatheatbypumpingthevapourelsewhereandcondensingit.Thismethodofpumpingheatfromoneplacetoanotherservedmankindwellwhenrefrigerators'mainjobswerepreservingfoodand,asairconditioners,coolin
3、gbuildings.Today'shigh-techworld,however,demandshigh-techrefrigeration.Heatpumpsarenolongeruptothejob.Thesearchisonforsomethingtoreplacethem. 2Onesetofcandidatesareknownasparaelectricmaterials.Theseactlikebatterieswhentheyundergoatemperaturechange：attachel
4、ectrodestothemandtheygenerateacurrent.Thiseffectisusedininfra-redcameras.Anarrayoftinypiecesofparaelectricmaterialcansensetheheatradiatedby,forexample,aperson,andthepatternofthearray'selectricaloutputscanthenbeusedtoconstructanimage.Butuntilrecentlynoonehad
5、botheredmuchwiththeinverseofthisprocess.Thatinverseexists,however.Applyanappropriatecurrenttoaparaelectricmaterialanditwillcooldown. 3SomeonewhoislookingatthisinverseeffectisAlexMischenko,ofCambridgeUniversity.Usingcommerciallyavailableparaelectricfilm,hea
6、ndhiscolleagueshavegeneratedtemperaturedropsfivetimesbiggerthananypreviouslyrecorded.Thatmaybeenoughtochangethephenomenonfromalaboratorycuriositytosomethingwithcommercialapplications. 4Astowhatthoseapplicationsmightbe,DrMischenkoisstillalittlehazy.Hehas,ne
7、vertheless,setupacompanytopursuethem.Heforeseesputtinghisdiscoverytouseinmoreefficientdomesticfridgesandairconditioners.Therealmoney,though,maybeincoolingcomputers. 5Gadgetscontainingmicroprocessorshavebeengettinghotterforalongtime.OneconsequenceofMoore'sL
8、aw,whichdescribesthedoublingofthenumberoftransistorsonachipevery18months,isthattheamountofheatproduceddoublesaswell.Infact,itmorethandoubles,becausebesidesincreasinginnumber,thecomponentsaregettingfast
