简介:Ca8Mg(SiO4)4Cl2:Eu2+phosphordopedwithSr2+cationforCa2+partially,wassynthesizedbysolid-statereactionathightemperatureunderreducingatmosphere,anditsluminescentpropertieswereinvestigated.TheexperimentalresultsindicatethattheemissionintensityofthephosphorincreasesafterbeingdopedwithafewamountofSr2+ion.Theemissionpeakofthephosphorblueshifttoabout464nmwhenthephosphorisdopedwithlargequantityofSr2+ions.TheexcitationspectrumindicatesthatthephosphorcanbewellexcitedbyUVandbluelightfrom300to460nm,andthephosphorwasfittedwellfortheexcitationbyUVorblue-LED.
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简介:FluorescencespectraofSm2+andEu2+→Sm2+energytransferwerestudiedinSrB4O7.Thereappearsonlyfluorescencefrom5D0transitionofSm2+at77K.Thevibroniclinesassociatedwith5D0→7F0transitionwereobserved.Thethermalpopulationtoupperstatesof5D1and4f5dlevelsfrom5D0givesriseto5D1→7FJand5d→4fradiativetransitionsofSin2+athighertemperature.
简介:TheNd3+3.2%(atomfraction):KGd(WO4)2crystalwasgrownbyKyropoulosmethod.TheabsorptionspectrumandfluorescencespectrumofNd3+:KGWcrystalweremeasured.Theabsorptioncrosssectionsat808nm(0.6799×10-20cm2)werecalculated,andtheoutputwavelengthoffluorescenceis1064and1351nm.Thediode-pumpedlaserwasoperatedbothinthefree-runningandpassivelyQ-switchedoperatingmodes.Themaximumlaseroutput(1064nm)is326mWwith62.7%slopeefficiencywheninputenergyis900mW.ThebeamqualityfactorM2≈1.1.Thegreenlightof532nmisobtainedinfrequencydoublingoperation.ThelaserispassivelyQ-switchedbyusingCr4+:LuAGassaturableabsorber.Thepulsewidthis170nsatrepetitivefrequencyof15kHZ.
简介:TheNaGd(WO_4)_2:Eu~(3+)phosphorswerepreparedbythemicroemulsionmediatedhydrothermalmethod.ThemorphologyandsizeofthesamplescouldbedependentonthepHintheinitialsolution.Thesephosphorsobtainedhadastrongabsorptionat395nmmatchingwiththepopularemissionofnear-UVLEDchips,andcouldemitintenseredlightat616nm.Thesmallellipsoid-likeparticlesorshortrodswereprovidedwithlargeparametersofoscillatorstrength?_2andasymmetryratio.Comparedtotheellipsoid-likephosphors,therod-likephosphorstookonstrongeremission,longerlifetimeandlargerquantumefficiency.Thisworkdemonstratedthattheone-dimensionNaGd(WO_4)_2:Eu~(3+)phosphorsmightbeamorefavorabledevicethanzero-dimensiononesforphotoluminescence.
简介:Sr1.995–1.5xGdxSiO4:0.005Eu2+phosphorserieswithx=0–0.08molfornear-ultravioletwhitelight-emittingdiodes(NUVw-LEDs)weresynthesizedviasolid-statereactionmethod.XRDprofilepatternandrefinementresultsdemonstratedthatdopingGd3+ionsresultedinthephasetransformation(β-Sr2SiO4→α’-Sr2SiO4).Thephotoluminescencespectrumofthesamplewithx=0moldisplayedtwoemissionpeakscenteredat470and525nm.Thetwo-peakspectrabecameone-peakspectrawiththeGd3+concentrationincreasing.Actually,thefittingresultsdemonstratedthattheone-peakspectrawerestillcomposedoftwosingleemissionspectra.ThephotoluminescenceintensitywasimprovedandtheCIEchromaticitycoordinateswereadjustedviadopingGd3+.
简介:Organicsubstancesuchassolventandresin'seffectonluminescentcapabilityofSrAl2O4:Eu2+,Dy3+phosphorwasstudied.Someorganicsolventsandresinswereselectedforexperimentation.TheresultsindicatethatthoseorganicsolventswillnothavenegativeeffectontheappliedcapabilityofSrAl2O4:Eu2+,Dy3+phosphor.Adoptingtheorganicresinsandcoveringmethod,theafterglowluminanceofSrAl2O4:Eu2+,Dy3+phosphorwasincreasedby85.01%and82.51%.
简介:TheextractionofCe(Ⅳ)inH2SO4/H3PO4systemwasinvestigatedsystematicallyusingbifunctionalionicliquidextractants(Bif-ILES)[A336][P507],[A336][P204]and[A336][C272]inn-heptane.TheeffectsofH2SO4concentration,extractantconcentrationandsalting-outagentconcentrationwereobservedindetail.TheextractionmechanismofCe(Ⅳ)inH2SO4/H3PO4systemwasobtained.ThecomparisonwithotherextractantssuchasCyanex923,TBPwasalsostudied.Thermodynamicfunctionsoftheextractionreactionwerecalculated,showingthattheextractionwasanexothermicprocess.TheseparationofCe(Ⅳ)fromRE(Ⅲ)andTh(Ⅳ)wasalsoinvestigated.TheresultindicatedthatCe(Ⅳ)couldbeselectivelyextractedinthissystem.CePO4nanoparticleswereobtainedintheprocessofstrippingusingH2O2inH2SO4/H3PO4system.X-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andspectroscopywereadoptedforthecharacterizationofthesample.
简介:Reactionof(MeC5H4)3LnwithHOCH2CH2NMe2intetrahydrofuran(THF)givesthenewcomplexes[(MeC5H4)2Ln(μ-OCH2CH2NMe2)]2(Ln=Sm,Y,Nd)withnitrogenfunctionalizedμ-alkoxideligand.ThecomplexeswerecharacterizedbyelementalanalysisandIR,and[(MeC5H4)2Sm(μ-OCH2CH2NMe2)]2wasstructurallycharacterizedbytheX-raydiffractiontobeadimerformedbytwounsymmetricoxygenbridges.ThecomplexhasatricyclicskeletonwiththeadditionaltwoSm-NbondsviaintramolecularcoordinationofOCH2CH2NMe2.ThecoordinationnumberofthecentralmetalSmisnine.Thetitlecomplexesshowgoodcatalyticactivityforring-openingpolymerizationofε-caprolactone.
简介:OpticalabsorptionandemissionintensitiesofNd3+ioninKLu(WO4)2crystalwereinvestigated.BasedontheJudd-Offelttheory,wecalculatedthefollowingspectralparameters:phenomenologicalintensityparametersΩ2=5.567×10–20,Ω4=3.597×10–20,andΩ6=3.800×10–20cm2.Theradiativelifetimeoflevels4F3/2was182.58μs.Thefluorescencebranchingratioforthetransition4F3/2→4I11/2was46.98%.Inaddition,theradiativetransitionprobabilitiesAJ,J’,oscillatorstrengthsPJ,J’andthevaluesofinte...
简介:ThereactionofNdCl3withlithiummethylnaphthalenein1:2moleratioinTHFgeneratesblackpowder.Thepowderreactswithcyclooctatetraene(COT)inTHFtoformthetitlecomplex.[Li(THF)4Nd(C8H8)2]·2THFcrystallizesinthemonoclinicspacegroupP2/cwithunit-celldimensionsa=1.7858(7)nm,h=1.3243(4)nm,c=1.8086(6)nm.β=106.52(4)°,V=4.10nm3andDc=1.268g/cm3forZ=4.F(000)=1660,R=0.0774,Rn=0.0733.Thecomplexconsistsofdiscreteion-pairandtwoTHFmoleculesadduct.Intheanion,theneodymiumatomiscoordinatedbytwoCOTrings.ThestructureofthecationshowsthatthelithiumatomisattachedwithTHFmoleculesonly.
简介:采用高温固相法合成尖晶石LiMn2O4,并以化学沉积方式对其进行包覆氧化钴的表面处理。通过X射线衍射(XRD)、扫描电镜(SEM)等技术对表面处理前后的LiMn2O4进行表征,分析了表面处理后LiMn2O4物理特性的变化,并结合电化学性能测试,研究了表面处理及其工艺和条件对LiMn2O4电化学容量与循环性能的影响。结果表明,表面处理后LiMn2O4循环性能显著提高。随氧化物含量的增加,循环性能提高,容量降低。未经表面包覆的LiMn2O4首次充放电容量为108.13mAh/g,50次循环充放电后容量衰减26.3%。500℃加热处理的表面包覆0.5%、2%氧化钴的LiMn2O4首次循环放电容量各为118.38mAh/g、115mAh/g,经过50次充放电循环后,容量分别降低8%、7%。
简介:RE-dopedNi-basedcatalystswerepreparedbysol-gelmethod.ThesecatalystswereappliedtothereactionofCO2reformingCH4tosyngas.ThestudiesrevealthatRE-doped(RE=La,Ce,Sm,Yb)Ni-basedcatalystsshowhighercatalyticactivitythanundopedNi-basedcatalyst,andwiththeincreasingofRE-dopedquantity,thecatalyticactivityofcatalystsexhibitsregularchanges.WhenRE-dopedquantityis0.2%(molarratio),thecatalystsshowthebestcatalyticactivity.