简介:TheNi-AlalloycontainingCr,FeadditiveswerepreparedasRaneyNiCatalystbyhighenergymilling.ThesizeandsurfacestateofNi-Alalloypowderwerestudiedbyparticlesizeanalyzerandsanningelectronmicroscopy.theStructurewasanalyzedbyXRDandMoessbauermethods.Theresultsshowedthatafterahigh-energymilling(HEM).theNi-Alalloytransformstoanano-scaleNiAlstructurewithrichAl.Byannealingthealloy,ametastableNi2Al3phasecanbeobtained.
简介:ThegrowthdetectsinNd:YCa4O(BO3)3(Nd:YCOB)crystalswereinvestigatedbytransmissionsynchrotrontopography.ItwasfoundthatgrowthstriationsweretheprimarydefectsinNd:YCOBcrystals.Grown-indislocations.mosaicblocksandinclusionswerealsoobseredinthecrystals.Theeffectoftemperaturefieldontheformationofgrowthdefectsinthecrystalswasdiscussed.
简介:采用EXAFS方法研究了经中温等温和低温LN2处理的2mol%Y2O3-ZrO2陶瓷中Zr^4+和Y^3+离子的近邻结构。结果表明,与中温等温试样相比,LN2处理的试样中Zr-O层和Zr-Zr(Y)层的配位数显著减少,平均键长明显缩短;Y-O层配位数减少,Y-Zr(Y)层平均键长伸长;各配位层畸变程度均增大。两个试样的Y-O层配位数均高于Zr-O层配位数,表明点阵中的氧空位倾向于与Zr离子为邻。分析认为,该试样Zr-O配位层中较多的氧空位主要来源于从高温快速冷却时所保留下来的Schottky缺陷,对四方相稳定性和中温相变具有重要的影响。
简介:WestudiedthespatialevolutionoftheFe-Niplasmageneratedbythefundamental(1064nm)andsecond(532nm)harmonicsofaQ-switchedNd:YAGlaser.Theexperimentallyobservedlineprofilesoftheneutraliron(FeI)havebeenusedtoextracttheplasmatemperature(Te)usingtheBoltzmannplotmethod,whereastheelectronnumberdensity(Ne)hasbeendeter-minedfromtheStarkbroadening.Inaddition,westudiedthespatialbehaviorofTeandNewiththevariationoflaserenergyforironplasmabyplacingthetargetmaterial(iron-nickelalloy)inairatatmosphericpressureforbothmodesoftheNd:YAGlaser.
简介:研究KTiOAsO4晶体的生长缺陷,对于改善它的性能和应用前景,有很大的意义。本文利用化学腐蚀光学显微术和同步辐射X射线形貌术研究了KTiOAsO4晶体的缺陷,实验结果表明,两种腐蚀剂对于显示KTA晶体的表面缺陷效果显著,KTA晶体中主要的缺陷有铁电畴、生长层、扇形界、位错和包裹物。讨论了这些缺陷形成的原因。
简介:LiNdP4O12(LNP)晶体是一种新型的激光材料。本文报道了用同步辐射X射线白光形貌术和光学显微法研究由助熔剂籽晶旋转法生长的LNP晶体的生长缺陷,观察到了圆形生长台阶及精细的系列台阶结构,对晶体中的包裹物和位错缺陷等进行了详细的观察描述,还发现了一种比较奇特的腐蚀沟槽,分析了这种腐蚀沟槽的形成机理及各种缺陷的成因和克服办法。
简介:报道了用同步辐射X射线白光形貌术和光学显微法研究由助熔剂籽晶旋转法生长的LNP晶体的生长缺陷。本文除对晶体中的包裹物和位错缺陷等进行了详细观察描述外,还发现了一种比较奇特的腐蚀沟槽。最后分析了这些缺陷的成因和克服办法。
简介:Alowpoweratmosphericpressureplasmajetdrivenbya24kHzACpowersourceandoperatedwithaCH4/airgasmixturehasbeeninvestigatedbyopticalemissionspectrometer.Theplasmaparametersincludingtheelectronexcitationtemperature,vibrationaltemperatureandrotationaltemperatureoftheplasmajetatdifferentdischargepowersarediagnosedbasedontheassumptionthatthekineticenergyofthespeciesobeystheBoltzmanndistribution.TheelectrondensityatdifferentpowerisalsoinvestigatedbyHβStarkbroadening.Theresultsshowthattheplasmasourceworksundernon-equilibriumconditions.Itisalsofoundthatthevibrationaltemperatureandrotationaltemperatureincreasewithdischargepower,whereastheelectronexcitationtemperatureseemstohaveadownwardtrend.Theelectrondensityincreasesfrom0.8×1021m-3to1.1×1021m-3whenthedischargepowerincreasesfrom53Wto94W.
简介:Insituwhite-beamsynchrotronradiationtopographicobservationsunderanelectricfieldhavebeenmadeontheKTiOPO4(KTP)familyofcrystals.Theinvestigationshowsastrongenhancementofdiffractedintensityforhklreflections(l≠0)andtopographiccontrastintheformoffinestriationswhentheexternalelectricfieldisparalleltothepolaraxis.Severalkkindsofdopedandundopedsampleswithvariousgrown-indefects,suchasdomainboundaries.growthstriations,growth-sectorboundaries.dislocations.etc.,havebeenstudiedindetail.Theresultssuggestthatthesedefectshaveverylittleeffectonthefield-inducedstriations,ItisbelievedthatthemovementofK^+ionsdrivenbytheelectricfieldleadstoalocalaccumulationofchargesandalatticedistortion.Thestronlyanisotropicconductivityisagoverningfactorintheexplanationofthefield-relatedphenomenainthiskindofquasi-one-dimensionalconductor.