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1、SolarPowerwithoutSolarCellsAdramaticandsurprisingmagneticeffectoflightdiscoveredbyUniversityofMichigan1researcherscouldleadtosolarpowerwithouttraditionalsemiconductor-basedsolarcells.Theresearchersfoundawaytomakean"optical battery ,"saidStephenRand,aprofessorinthedepartmentsofElectricalEngineeri
2、ngandComputerScience,PhysicsandAppliedPhysics.Lighthaselectricandmagneticcomponents.Untilnow,scientiststhoughtthe effects ofthemagneticfieldweresoweakthattheycouldbeignored.WhatRandandhiscolleaguesfoundisthatattherightintensity,whenlightistravelingthroughamaterialthatdoesnotconductelectricity,the
3、lightfieldcangeneratemagneticeffectsthatare100milliontimesstrongerthan previously expected.Under thesecircumstances,themagneticeffectsdevelopstrengthequivalenttoastrongelectriceffect."Thiscouldleadtoanewkindofsolarcellwithoutsemiconductorsandwithoutabsorptiontoproducechargeseparation,"Randsaid
4、."Insolarcells,thelight goesintoamaterial,getsabsorbedandcreatesheat.Here,weexpecttohaveaverylowheatload2.Insteadofthelightbeingabsorbed,energyisstoredinthemagneticmoment3.Intensemagnetizationcanbeinducedbyintenselightandthenitisultimatelycapableofprovidingacapacitivepowersource."Whatmakesthisposs
5、ibleisapreviouslyundetectedbrandof"opticalrectification4,"saysWilliamFisher,adoctoralstudent5inappliedphysics.Intraditionalopticalrectification,light'selectricfieldcausesachargeseparation,orapulling apart ofthepositiveandnegativecharges6inamaterial.Thissetsupavoltage,similarto that inabattery.
6、RandandFisherfoundthatundertherightcircumstancesandinrighttypesofmaterials,thelight'smagneticfieldcanalsocreateopticalrectification.Thelightmustbeshonethrough7a material thatdoesnot conduct electricity,suchasglass.Anditmustbefocusedtoanintensityof10millionwattspersquarecentimeter8.Sunlightisn'
7、tthisintenseonitsown,butnewmaterialsarebeingsoughtthatwouldworkatlowerintensities,Fishersaid."Inourmostrecentpaper,weshowthatincoherentlight9likesunlightistheoreticallyalmostas. effective inproducingchargesepar
