简介:1.IntroductionLightrareearthadditioncanremarkablyenhancetheservicelifeofFe-Cr-Alalloyforelectricalheatingelement,butitscontentinthealloymustbecontrolledbelowthelevelof0.1wt-%.Whenthecontentexceedsthat,theperformance
简介:
简介:WehavestudiedtheMossbauereffectofYBa2Cu2.88Fe0.12O7-xsuperconductiveoxidefrom78to273K.TwominimaofrecoillessfractionandDebyetemperaturewerefoundnear110Kand220K.Itmeansthatlatticesofteninghappenednearthesetwotemperatures.Wealsoobservedminimaofisomershiftnear110Kandquadrupolesplittingincreasewhentemperatureislowerthan110K.Wesuggestthatlatticesofteningwouldleadtothedisplacementofoxygenatoms.Thismayberelativetosuperconductivetransition.
简介:第三产生同步加速器X光象自然材料一样为许多设计材料的微结构描述提供一个崭新的机会。这篇文章为结构的材料的学习表明三种技术的用法:微分孔的X光检查显微镜学(DAXM),三维的X光检查衍射(第3DX),和散布的同时的宽angle/small角度X光检查(蜡/萨克斯风管)。DAXM能与高空间、尖的分辨率在多晶的材料测量3D谷物结构。在使变形的材料,streaked衍射山峰能被用来在单个谷物分析本地脱臼内容。比作DAXM,第3DX能大批印射谷物材料更快速在损坏空间分辨率的情况下。当材料在变丑下面时,发展微观结构,为学习是很有用的。蜡/萨克斯风管对与不同类的结构学习材料合适,例如猛抛加强的合金。蜡和萨克斯风管揭示的结构的信息能为更深的卓见被合为材料行为。这三种技术的未来开发和应用程序将也被讨论。
简介:Intrinsiccarrierconcentration(ni)isoneofthemostimportantphysicalparametersforunderstandingthephysicsofstrainedSiandSi1-xGexmaterialsaswellasforevaluatingtheelectricalpropertiesofSi-basedstraineddevices.Uptonow,thereportonquantitativeresultsofintrinsiccarrierconcentrationinstrainedSiandSi1-xGexmaterialshasbeenstilllacking.Inthispaper,byanalyzingthebandstructureofstrainedSiandSi1-xGexmaterials,boththeeffectivedensitiesofthestatenearthetopofvalencebandandthebottomofconductionband(NcandNv)at218,330and393KandtheintrinsiccarrierconcentrationrelatedtoGefraction(x)at300KweresystematicallystudiedwithintheframeworkofKPtheoryandsemiconductorphysics.ItisfoundthattheintrinsiccarrierconcentrationinstrainedSi(001)andSi1-xGex(001)and(101)materialsat300KincreasessignificantlywithincreasingGefraction(x),whichprovidesvaluablereferencestounderstandtheSibasedstraineddevicephysicsanddesign.
简介:ThetransportpropertiesintheLa2/3(Ca1-xSrx)1/3MnO3(x=0,1/3,2/3)filmspreparedusingtheRFmagnetronsputteringmethodwereinvestigated.TheeffectoftheCa,Srdouble-dopingattheApositionintheLa2/3A1/3MnO3onthestructureofthetargetsandtransportofthefilmshasbeenstudied.Withtheincreaseofx,thestructuresofthetargetstransformfromtherhombohedralphasetothecubicphase;themetal-insulatorphasetransitiontemperature(Tp)ofthefilmsincreases;andthecorrespondingpeakresistivitydecreases.Allthephenomenacanbequalitativelyexplainedbythelatticeeffect.