学科分类
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9 个结果
  • 简介:Europium(Ⅲ)-dopedYF3ispreparedbyahydrothermalprocessat200℃.X-raydiffraction(XRD)patternidentifiestheformationofYF3phasewithoutdetectableimpurity.Environmentscanningelectronmicroscopy(ESEM)imageshowstheevensizedistributionofthesampleswithcubicmorphology.TheexcitationandemissionspectraoftherareearthionsdopedYF3areinvestigatedbyfluorescencespectrophotometer.Theexcitationspectrumfor591nmemissionhasseveralexcitationbandsat320,365,386,397and467nm,andthemainpeakvaluewas397nm.TypicalEu3+emissionpeaksat591nm(5D0→7F1)and612nm(5D0→7F2)areobservedwhenexcitedby397nm,andthestrongestemissionis591nm,demonstratingthattherareearthionsoccupythecentrosymmetricalsitesinYF3.

  • 标签: HYDROTHERMAL synthesis RARE earth ion YF3
  • 简介:Bothenantiomersoffluoxetineweresynthesizedinfivestepsfromethylbenzoylacetate(1)usingmicrobial-chemicalapproachwithoverallyieldsof59%and62%respectively.(S)-Enan-tiomercanbeobtainedin>99%e.e.byrestingcellofbaker’syeastandtheRformwasproducedin81%e.e.byimmobilizedGeotrichumsp.G38.

  • 标签: microbial YEAST GEOTRICHUM RESTING ASYMMETRIC steps
  • 简介:AseriesofdoubleperovskitesRSrMnFeO_6(R=La,Pr,Nd,Sm)wassynthesizedundermildhydrothermalconditions.Crystalgrowthsofthesamplesweresensitivetoalkalinity,temperature,fillingfraction,andcompositionofinitialreactionmixture.ThedesiredseriesofcompoundsbelongstotheclassofAA'BB'O_6perovskiteswitharandomdistributionofMnandFeatomsovertheB-cationsub-lattice.TheirstructuresshowthedistortedorthorhombicsymmetrywithspacegroupPnma.TheshapesandsizesofthecrystalswereanalyzedonaRigakuJSM-6700Fbyscanningelectronmicroscopy.AnalysisdonebyXPS,MssbauerspectroscopyandiodometrictitrationrevealsthatMnandFeionshave+4and+3oxidationstates,respectively.

  • 标签: 钙钛矿相 水热合成 扫描电子显微镜 表征