简介:LuminescencelifetimeofCe(Ⅲ)forCe0.9RE0.1P5O14,whereREdenotesrareearthionsotherthanCe(Ⅲ),wasmeasuredbymeansofthetime-correlatedsinglephotoncountingtechnique.Ithasbeenfoundthatthelifetimedataarecapableofelucidatingtheenhancementorquenchingofcerium(Ⅲ)luminescencebyalienREions(otherthanCe)indoublydopedceriumpentaphosphatecrystal.
简介:ThechemicalstateofgrainboundarycosegregationofCeandPinFe-P-CealloysystemwasstudiedbymeansofAugerElectronSpectroscopy(AES).TheAugerpeaksofCesegregatedatgrainboundariesarefoundwithintherangeof60~180eV.BycomparingwiththeAugerspectraoftheFe-Ce-Pintermetalliccompound,itissupposedthatthereisatwo-dimensionalinterfacialphaseatgrainboundarieswithCeandPcosegregationwhichissimilartothestructureoftheFe-Ce-Pcompound.
简介:Thecrackingandaromatizationofn-hexaneoverH-ZSM-5modifiedbyvariousrareearthswereinvestigatedbymeansofcontinuousflowmicro-reactor.ThesurfacepropertiesofmodifiedH-ZSM-5catalystswereobtainedfromIR,XRDandXPS.Theresultsshowthattherareearthsenhancethearomatizingpropertiesofthecatalystswhicharepreparedbymechanicalmixturemethod.Theresultsofn-hexanecrackingandaromatizationarecorrelatedwiththeacidity.TheBrnstedacidicsitesaretheactivesitesofn-hexanearomatization,whileLewisacidsiteplaysanimportantroleinn-hexanecracking.
简介:ThemeasurementsoftemperaturedependenceofthemagneticsusceptibilityofLa1-xSrxCoO3perovskiteoxidesatdifferentSrdoping(0≤x≤0.5)andannealingtemperaturewerepresented.Forthesamplewithx=0.1,ashoulderwasobservedaround150K,andapeakwhichisonefeatureofspinglassappearedaround50Kinthecurveofsusceptibilityversustemperature.Thehigh-temperature(250~420K)susceptibilityfitswellwithCurie-Weisslawforallsamples.WeissconstantandeffectivemagneticmomentweredeterminedandtheirvariationswithSrdopingandoxygenannealingconditionwereobtained.TheWeissconstantincreasesmonotonouslywithSrcontentforx>0.2.Thevaluesofeffectivemomentswereinterpretedwiththespinstateofcobaltions.Studiesonthesusceptibilitiesofthesampleswithx=0.2underdifferentpreparationtemperaturesandannealingtemperaturesshowthattherisingofsinteringtemperatureandannealingtemperaturewillincreasethepara-ferromagnetictransitiontemperature,andreducetheeffectivemomenttonormalvalue.OurresultshowsthatbothCo3+andCo4+ionsshouldbeinISstateafterannealingandtheoxygenannealingcausesthetransitionofCo3+spinstatefromHStoIS.
简介:探讨了在大生产条件下4Cr5MoSiV1钢的脱碳层测定原则。结果表明,金相法测定结果较准确且操作简便