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1、Inanewstudy,publishedinScierice,ColumbiaEngineeringresearchersdemonstratethatgraphene,evenifstitchedtogetherfrommanysmallcrystallinegrains，isalmostasstrongasgrapheneinitsperfectcrystallineform.Thisworkresolvesacontradictionbetweentheoreticalsimulations,whichpredictedthatgrainboundariescanbestr
2、ong,andearlierexperiments,whichindicatedthattheyweremuchweakerthantheperfectlattice(格子)・Grapheneconsistsofasingleatomiclayerofcarbon,arrangedinahoneycomblattice.“OurfirstScieneepaper,in2008,studiedthestrengthgraphenecanachieveifithasnodefects--itsintrinsicstrength,”saysJamesHone,professorofmec
3、hanicalengineering,wholedthestudywithJeffreyKysar,professorofmechanicalengineering.HButdefect-free,pristinegrapheneexistsonlyinverysmallareas・Large-areasheetsrequiredforapplicationsmustcontainmanysmallgrainscormectedatgrainboundaries,anditwasunclearhowstrongthosegrainboundarieswere・This,oursec
4、ondScieneepaper,reportsonthestrengthoflarge-areagraphenefilmsgrownusingchemicalvapordeposition(CVD),andwe'reexcitedtosaythatgrapheneisbackandstrongerthanever.”Thestudyverifiesthatcommonlyusedmethodsforpost-processingCVD-growngrapheneweakengrainboundaries,resultingintheextremelylowstrengthseeni
5、npreviousstudies.TheColumbiaEngineeringteamdevelopedanewprocessthatpreventsanydamageofgrapheneduringtransfer.”Wesubstitutedadifferentetchantandwereabletocreatetestsampleswithoutharmingthegraphene「notesthepaper'sleadauthor,Gwan-HyoungLee,apostdoctoralfellowintheHonelab・“Ourfindingsclearlycorrec
6、tthemistakenconsensusthatgrainboundariesofgrapheneareweak.Thisisgreatnewsbecausegrapheneofferssuchaplethoraofopportunitiesbothforfundamentalscientificresearchandindustrialapplications.MInitsperfectcrystallineform,graphene(aone-atom-thickcarbonlayer)isthestrongestmaterialevermeasured,astheColum
7、biaEngineeringteamreportedinScieneein2008•-sostrongthat,asHoneobserved,“itwouldtakeanelephant,balaneedonapencil,tobreakthroughasheetofgraphenethethicknessofSaranWrap.”Forthefirststudy,theteamobtainedsmall,structurallyperfectflakesofgrap
