CompositeMaterials复合材料中国材料研究学会.docx
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CompositeMaterials复合材料中国材料研究学会
Vol.80,2015
*E-Material
*MetalAlloy
*Organic&Polymer
*CompositeMaterials
*PracticalApplication
*TechNews&NewTech
MCanxixunInformationandNewsService
MCanxixunInformationandNewsService
Contents
TechNews&NewTech(技术前沿)3
Researchersmanipulategold-coatednanoparticleswithlasers3
研究人员利用激光束操作镀金纳米颗粒4
Studyhelpsunderstandwhyamaterial’sbehaviorchangesasitgetssmaller4
有助于理解材料在变小时特性发生改变的原因的研究6
Squeezingoutnewsciencefrommaterialsinterfaces7
材料界面新科学8
New“knobs”candialincontrolofmaterials10
新“旋钮”控制材料性能11
MetalAlloy(金属合金)11
Watchingalloyschangefromliquidtosolidcouldleadtobettermetals11
合金由液态变为固态或产生更好的金属13
CompositeMaterials(复合材料)15
ThermHexWabendevelopOne-StepProductionProcessforSandwichMaterials15
ThermHexWaben开发出“一步式”夹层材料生产工艺15
Artificialskinchangescolourtoorder16
人造材料改变颜色17
USmovestodevelopcompositemarket17
美国将开发复合材料市场18
PracticalApplication(实际应用)18
Newmaterialcapturescarbonathalftheenergycost18
新材料吸收二氧化碳,节能一半20
Researchersidentifymaterialstoimprovebiofuel,petroleumprocessing22
研究人员发现可提高生物燃料与石化工艺的材料24
Newmaterialtoproducecleanenergy25
可生产清洁能源的新材料26
Processidentifiedforimprovingdurabilityofglass27
提高玻璃耐用性的新方法28
Organic&Polymer(有机高分子材料)29
Fibersmadebytransformingmaterials29
转变材料制造纤维30
Opticalfiberslightthewayforbrain-likecomputing31
光学纤维为类脑计算奠基32
E-Material(电子材料)33
Thefutureofelectronicscouldlieinmaterialfromthepast33
过去的材料决定电子设备的未来33
Simulationsprovidenewinsightintoemergingnanoelectronicdevice34
模拟为纳米电子设备提供新思路35
Technologycouldcutcostsofnightvision,thermalimaging36
新技术可以降低夜视与热成像的成本37
Newtechnologymaydoubleradiofrequencydatacapacity38
新技术或使无线电频率数据容量加倍39
TechNews&NewTech(技术前沿)
Researchersmanipulategold-coatednanoparticleswithlasers
Tinyglassnanospherescoatedononesidewithaveryfinegoldfilm:
LudwigMaximillianUniv.ofMunich(LMU)scientistshaveshownthatparticlesmodifiedinthiswaycanbemovedaboutwithhighprecisionusinglaserbeams,creatinganopticallycontrolledmicro-elevator.
Theyowetheirnametothetwo-facedRomangodJanus.Symboloftheturningyear,Januslooksbackandlooksforwardatthesametime,justlikeso-calledJanusparticles,whichdisplaytwodifferentfacestotheworld.AresearchteamledbytheLMUphysicistsProf.JochenFeldmannandDr.AlexanderUrban,bothaffiliatedwiththeNanosystemsInitiativeMunich(NIM)ClusterofExcellence,hasnowsynthesizedaclassofJanusparticleswhich,thankstothedistinctpropertiesoftheirtwohemispheres,canbemanipulatedwithunprecedentedprecisionwithlaserbeams.
Ifalaserbeamisfocusedbythelensofamicroscope,itcanbeusedasanopticaltweezerstotrapananoparticleatthefocalpointofthebeam.Theeffectmakesuseoftheforcesexertedbythescatteringofthelightwavesthatimpingeontheparticle."Theabilitynotjusttotrapparticles,butalsotocontroltheirdisplacementbymeansoflaserlightwouldbeextremelyusefulforawiderangeofapplications,suchastheanalysisofliquidsampleswiththeaidofmicrofluidicschips,"saysUrban.Butuptonow,opticaltweezersforthispurposewashamperedbythefactthatthepositionanddirectionofdisplacementofparticlescouldnotbecontrolledwithsufficientprecision."
Asymmetricgildingallowsmanipulation
Urban'steamhasnowovercomethislimitation,byusingquiteasimpletrick:
Thescientistsintroducedanasymmetryintothesystembycoatingglassnanosphereswithawafer-thinlayerofgoldononeface.Thislayerisonly5nmthick,about20timesthinnerthangoldleaf,"saysUrban.Thegold-coatedhemisphereofsuchaso-calledJanusparticleheatsupwhenirradiatedbythelaserbeam,whiletheglasssideisunaffectedbecauseitisnotmetallicanddoesnotconductheat.IfsuchaJanusparticleisplacedinwater,heatingofthegoldsurfacegeneratesatemperaturegradient,whichcausestheparticletomoveupwardstowardthelightsource.
Controlofthedirectionofmovement
Howfaritmovesandinwhichdirectioncanbepreciselycontrolledbymodifyingthebalanceofforcesexertedbythelaserontheparticle:
Scatteringforcescontroltheorientationoftheparticleinspaceandconfineitwithinthebeam,whiletheintensityofthelasercanbeusedtoalterthelevelofheatingandhencetoregulatethedistancetraversedbytheparticleinthethirddimension.Thus,byvaryingthelaserpower,theresearcherscanraiseorlowertheleveloftheparticlewithinthelaserbeam,asifitwereapassengerinanelevator:
Increasingtheintensityofthebeamcausestheparticletorise;reducingthepowerresultsindownwardmotion.
"Thisnewtechniqueallowsonetocontrolparticlemotionswithunprecedentedprecisionandcanbeusedinmanydifferentandinterestingsettings",saysUrban.Indeed,thescientistshavealreadytakenafurtherstepbysuccessfullyusinglaserbeamstocaptureagoldnanospheretogetherwiththenewJanusparticleandthenshowingthattheycouldchangethedistancebetweenthetwoparticlesatwill."Thisdemonstratesthatourlaser-powered'elevator'providesaversatiletoolforuseinbasicresearchaswellasinmanypracticalapplications.Itcould,forexample,serveasthebasisofadeviceforthemeasurementofextremelyweakforces,inwhichamoleculeissuspendedbetweenparticlesandonecouldusethelasertomeasuretheforcerequiredtopulltheparticlesapart,"saysUrban.
Source:
LudwigMaximillianUniv.ofMunich
研究人员利用激光束操作镀金纳米颗粒
微小的玻璃纳米微球在一侧包覆了非常细的金薄膜。
慕尼黑-路德维希-马克西米利安大学(LMU)的科学家研究发现,通过这种方法修改的颗粒可以用采用高精度的激光束进行移动,制造出一个光控制的微电梯。
他们以罗马两面神Janus来命名。
作为一年更替的象征,Janus能够同时向前后两面看,就像所谓的Janus颗粒一样能向世界展示两个不同的面孔。
由隶属于慕尼黑纳米系统研究基地的LMU物理学家JochenFeldmann教授和AlexanderUrban博士领导的一个研究小组现已合成了一类Janus颗粒。
由于它们两个不同半球体的不同特性,可以通过激光束以前所未有的精度对这些颗粒进行操作。
如果通过显微镜镜片对激光束进行聚焦,它就可以用作光学镊子在光束的焦点处捕获纳米颗粒。
这种效果利用的是光波散射在颗粒上所施加的力。
Urban说:
“它能做的不仅仅是捕获颗粒,而且还能通过激光装置控制其移动,其应用范围将会非常广泛,比如借助微流体芯片来分析液体样本。
但是到现在为止,光学镊子在这方面的应用还面临着一定的阻碍,因为目前还不能以足够的精度来控制颗粒移动的位置和方向。
”
不对称镀金使操作成为可能
Urban的团队通过很简单的技巧克服了这种局限性。
这些科学家将不对称引入到该系统中,通过极薄的金薄膜在颗粒的一个面上对玻璃纳米微球进行了镀膜操作。
Urban说:
“这种膜只有5纳米厚,比金箔薄20倍左右。
”这种所谓的Janus颗粒的镀金半球在激光束照射时会变热,而玻璃的那一面不会受到影响,因为它不是金属的且不会导热。
如果这种Janus颗粒放入水中,加热金属表面会形成温度梯度,这会导致颗粒朝向光源向上移动。
控制移动方向
通过改变激光施加在颗粒上的力的平衡可以精确地控制它朝哪个方向移动以及能移动多远。
散射的力度控制颗粒在空间中的方位并将其限制在激光束范围之内,而激光的强度可用于改变热的程度并进而调节颗粒在三维空间移动的距离。
因此,通过改变激光功率,研究人员可以提高或降低激光束内的颗粒水平,就好像它是电梯的乘客一样。
增加激光束的强度会引起颗粒上升,而降低功率则会导致其向下移动。
Urban说:
“这种新的技术允许人们以前所未有的精度来控制颗粒运动,并且可应用于很多不同的有趣装置中。
”事实上,科学家们已经取得了很大的进展,成功利用激光束捕获了与Janus颗粒在一起的金纳米球,并且展示出他们有能力随意改变颗粒之间的距离。
Urban说:
“这表明我们的激光动力‘电梯’为基础研究和很多实际应用提供了一种通用工具。
例如,它可以用作一个装置的基础以通过极弱的作用力来进行测量,其中分子颗粒是悬浮的,我们可以使用激光来测量出把这些颗粒分开所需的力的大小。
”
来源:
慕尼黑-路德维希-马克西米利安大学
Studyhelpsunderstandwhyamaterial’sbehaviorchangesasitgetssmaller
Tofullyunderstandhownanomaterialsbehave,onemustalsounderstandtheatomic-scaledeformationmechanismsthatdeterminetheirstructureand,therefore,theirstrengthandfunction.
ResearchersattheUniv.ofPittsburgh,DrexelUniv.andtheGeorgiaInstituteofTechnologyhaveengineeredanewwaytoobserveandstudythesemechanismsand,indoingso,haverevealedaninterestingphenomenoninawell-knownmaterial,tungsten.Thegroupisthefirsttoobserveatomic-leveldeformationtwinninginbody-centeredcubic(BCC)tungstennanocrystals.
Theteamusedhigh-resolutiontransmissionelectronmicroscope(TEM)andsophisticatedcomputermodelingtomaketheobservation.Thiswork,publishedinNatureMaterials,representsamilestoneinthein-situstudyofmechanicalbehaviorsofnanomaterials.
Deformationtwinningisatypeofdeformationthat,inconjunctionwithdislocationslip,allowsmaterialstopermanentlydeformwithoutbreaking.Intheprocessoftwinning,thecrystalreorients,whichcreatesaregioninthecrystalthatisamirrorimageoftheoriginalcrystal.Twinninghasbeenobservedinlarge-scaleBCCmetalsandalloysduringdeformation.However,whethertwinningoccursinBCCnanomaterialsornotremainedunknown.
“TogainadeepunderstandingofdeformationinBCCnanomaterials,wecombinedatomic-scaleimagingandsimulationstoshowthattwinningactivitiesdominatedformostloadingconditions,duetothelackofothersheardeformationmechanismsinnanoscaleBCClattices.”saidScottMao,aprofessorintheSwansonSchoolofEngineeringattheUniv.ofPittsburgh.
TheteamchosetungstenasatypicalBCCcrystal.Themostfamiliarapplicationoftungstenistheiruseasfilamentsforlightbulbs.
Theobservationofatomic-scaletwinningwasmadeinsideaTEM.Thiskindofstudyhasnotbeenpossibleinthepast,duetodifficultiesofmakingBCCsampleslessthan100nminsize,asrequiredbyTEMimaging.JiangweiWang,agraduatestudentatUniv.ofPittsburgh,andMao,theleadauthorofthepaper,developedacleverwayofmakingtheBCCtungstennanowires.UnderaTEM,Wangweldedtogethertwosmallpiecesofindividualnanoscaletungstencrystalstocreateawireabout20nmindiameter.ThiswirewasdurableenoughtostretchandcompresswhileWangobservedthetwinningphenomenoninrealtimeusingahigh-resolutionTEM.
TobetterunderstandthephenomenonobservedbyMaoandWang’steamattheUniv.ofPittsburgh,ChristopherWeinberger,anassistantprofessorinDrexel’sCollegeofEngineering,developedcomputermodelsthatshowthemechanicalbehaviorofthetungstennanostructure—attheatomiclevel.Hismodelingallowedtheteamtoseethephysicalfactorsatplayduringtwinning.ThisinformationwillhelpresearcherstheorizewhyitoccursinnanoscaletungstenandplotacourseforexaminingthisbehaviorinotherBCCmaterials.
“We’retryingtoseeifouratomistic-basedmodel