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1、·六、完型填空SolarPowerwithoutSolarCells AdramaticandsurprisingmagneticeffectoflightdiscoveredbyUniversityofMichigan1researcherscouldleadtosolarpowerwithouttraditionalsemiconductor-basedsolarcells. Theresearchersfoundawaytomakean“optical51,”saidStephenRand,aprofess
2、orinthedepartmentsofElectricalEngineeringandComputerScience,PhysicsandAppliedPhysics. Lighthaselectricandmagnetic52.Untilnow,scientiststhoughttheeffectofthemagneticfieldweresoweakthattheycouldbe53.WhatRandandhiscolleaguesfoundisthatattherightintensity,whenligh
3、tistravelingthroughamaterialthatdoesnot54electricity,thelightfieldcangeneratemagneticeffectsthatare100milliontimesstrongerthanpreviouslyexpected.Underthesecircumstances,themagneticeffectsdevelopstrength55toastrongelectriceffect. “Thiscouldleadtoanewkindofsolar
4、cellwithoutsemiconductorsandwithoutabsorptiontoproducechargeseparation,”Randsaid.“Insolarcells,the56goesintoamaterial,getsabsorbedandcreatesheat.Here,weexpecttohaveaverylowheatload2.Insteadofthelightbeingabsorbed,energyisstoredinthemagneticmoment3.Intensemagnet
5、izationcanbeinducedbyintenselightandthenitisultimatelycapableofprovidingacapacitivepower57Whatmakesthispossibleisapreviouslyundetectedbrandof“opticalrectification,”saysWilliamFisher,adoctoralstudentinappliedphysics.Intraditionalopticalrectification,light'select
6、ricfieldcausesachargeseparation,orapulling58ofthepositiveandnegativechargesinamaterial.Thissetsupavoltage,similarto59inabattery. RandandFisherfoundthatundertherightcircumstancesandinrighttypesofmaterials,thelight'smagneticfieldcanalsocreateopticalrectification
7、.Thelightmustbeshonethrougha60thatdoesnotconductelectricity,suchasglass.Anditmustbefocusedtoanintensityof10millionwattspersquarecentimeter8.Sunlightisn'tthis61onitsown,butnewmaterialsarebeingsoughtthatwouldworkatlowerintensities,Fishersaid. “Inourmostrecentpap
8、er,weshowthatincoherentlight9likesunlightistheoreticallyalmost62effectiveinproducingchargeseparationaslaserlightis,”Fishersaid. Thisnew63couldmakesolarpowercheaper,theresea
