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ID:11432396
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页数:13页
时间:2018-07-12
《高中英语导学案与练2012高考英语:阅读理解课堂练学案(5)》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、2012高考英语:阅读理解课堂练学案(5)PassageEleven(SuperconductingMaterials)Thestoneage,TheIronAge.Entireepochshavebeennamedformaterials.Sowhattocallthedecadesahead?Thechoicewillbetough.Welcometotheageofsuperstuff.Materialscience--oncetheleastsexytechnology–isburstingw
2、ithnew,practicaldiscoveriesledbysuperconductingceramicsthatmayrevolutionizeelectronics.Butsuperconductorsarejustpartofthepicture:fromhouseandcarstocookpotsandartificialteeth,theworldwillsomedaybemadeofdifferentstuff.Exoticplastics,glassandceramicswillsh
3、apethefuturejustassurelyashavegeneticengineeringandcomputerscience.Thekeytothenewmaterialsisresearchers’increasingabilitytomanipulatesubstancesatthemolecularlevel.Ceramics,forexample,havelongbeenlimitedbytheirbrittleness.Butbyminimizingthemicroscopicimp
4、erfectionsthatcauseit,scientistsaremakingfarstrongerceramicsthatstillretainsuchqualitiesashardnessandheatresistance.FordMotorCo.nowusesceramictoolstocutsteel.AfirmcalledKyocerahascreatedalineofceramicscissorsandknivesthatstaysharpforyearsandneverrustorc
5、orrode.Asimilartransformationhasovertakenplastics.High-strengthpolymersnowformbridges,ice-skatingrinksandhelicopterrotors.Andonenewplasticthatgenerateselectricitywhenvibratedorpushedisusedinelectricguitars,touchsensorsforrobothandsandkaratejacketsthatau
6、tomaticallyrecordeachpunchandchop.Evenplasticlitter,whichoncethreatenedtopermanentlyblotthelandscape,hasprovedamenabletomoleculartinkering.Severalmanufacturersnowmakebiodegradableforms;someplasticsix-packringsforexample,graduallydecomposewhenexposedtosu
7、nlight.Researchersaredevelopingwaystomakeplasticsasrecyclableasmetalorglass.Besides,composites–plasticreinforcedwithfibersofgraphiteorothercompounds–madetheround-the-worldflightofthevoyagerpossibleandhaveevenbeenprovedincombat:ahelmetsavedaninfantryman’
8、slifebydeflectingtwobulletsintheGrenadainvasion.Someadvancedmaterialsareoldstandardwithanewtwist.Thenewestfiberopticcablethatcarrytelephonecallscross-countryaremadeofglasssotransparentthatapieceof100milesthickisclearerthanastanda
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