简介:Thesimplemodelfor4f-5dtransitionsoflanthanideionsincrystalswasextendedtodealwiththecaseoftheoctahedralcrystalfield,whereforthet2componentof5dorbitalsthespin-orbitinteractioncouldnotbeneglectedduetoincompletequenchingofthe5dorbitalangularmomentum.Theenergylevelsforthe4fN-15dconfigurationandtherelativelinestrengthsforthe4fN4fN-15dtransitionwerecalculatedindetail.Theresultwasappliedtotheinterpretationofthelow-temperature4f-5dexcitationspectrumofCs2NaYCl6∶Tb3+.
简介:Whitebody-color(Y,Gd)BxV1-xO4-x:Eu3+phosphorswerepreparedbycoprecipitationreaction.UnderVUVexcitationat147nm,theredemissioncolorimetricpurityof(Y,Gd)BxV1-xO4-x:Eu3+phosphorismuchbetterthanthatofcommercialPDP(plasmadisplaypanels)phosphor(Y,Gd)BO3:Eu3+.Butitsrelativeemissionintensityisonlyabout90%ofthecommercialphosphor.
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:Eu3+/Sm3+codopedBiPO4黄磷与没有表面活化剂的环境经由一个灵巧的热水的方法被综合。X光检查衍射分析证明样品拥有了标准BiPO4单斜晶的结构。扫描电子显微镜学图象证明所有样品与像梭的形状分散得好的、测微计大小的晶体创作了。到Eu3+的从Sm3+的精力转移被光系列和Sm3+4G5/26H5/2排放的腐烂过程证实。橘子红光能在Eu3+/Sm3+codopedBiPO4黄磷被获得。Sm3+4G5/26H5/2排放的平均一生在BiPO4:0.03Sm3+在BiPO4:0.03Sm3+从2.70ms减少了到2.37ms,0.05Eu3+。在395nm附近的强壮、宽的吸收乐队,从Eu3+的7F05L6转变和Sm3+的6H5/24K11/2转变发源,资助BiPO4:Eu3+,有近紫外激动的white-light-emitting二极管的域里的潜在的应用程序的Sm3+黄磷。
简介:TheNd60Fe20Al8Co10B2alloywaspreparedbysuctioncastingofthemoltenalloyintoacoppermoldunderargonatmosphere.Themicro-structuralandmagneticpropertychangesintheNd60Fe20Al8Co10B2alloyduringcrystallizationwereinvestigatedbyX-raydiffraction(XRD),differentialscanningcalorimetry(DSC),scanningelectronmicroscope(SEM)andthevibratingsamplemagnetometer(VSM).TheprecipitationandNd-richandFe-richphaseshavenosignificanteffectontheintrinsiccoercitityforNd60Fe20Al8Co10B2alloyannealedbelow723K.However,thegrowthofFe-richphasedecreasesthesaturatemagnetizationandremanenceofthealloy.Thehardmagneticbehaviorisdisappearedwhenthealloyisfullycrystallized.
简介:La15Fe77B8hydrogenstoragealloyswerepreparedusingavacuuminduction-quenchingfurnace.TheresultsofX-raydiffraction(XRD)andscanningelectronmicroscopy(SEM)suggestedthatLa15–xSmxFe2Ni76Mn5B2(x=0,2,4,6)alloyshadmultiphasestructureincludingthemainLaNi5phase,La3Ni13B2phaseand(Fe,Ni)phase.WiththeincreasingsubstitutionofSmforLa,themainphasestructureofalloysdidnotchange,whiletheunitcellvolumesdecreased,thecyclestabilitywasimprovedandthemaximumdischargecapacitydecreased,butthelowtemperaturemaximumdischargecapacityofthesamesubstitutionalloywasgraduallyapproachingthemaximumdischargecapacityatroomtemperature,whichshowedthatLa15Fe77B8hydrogenstoragealloysofthepartialsubstitutionofSmforLahadbetterlow-temperaturedischargeability(LTD).Forthesamesubstitutionalloys,self-dischargecharacteristicsandcyclestabilityatlowtemperaturewerebetterthanthatatroomtemperature.Furthermore,thehigh-ratedischargeability(HRD)andtheexchangecurrentdensityI0firstincreasedandthendecreasedwiththeincreasingofSmcontent,whereasthehydrogendiffusioncoefficientDinalloybulkdecreasedgradually,whichindicatedthatappropriatesubstitutionofSmforLaimprovedtheelectrochemicalkineticspropertiesofthealloys.TheHRDwasmainlydominatedbythecharge-transferrateonthealloysurface.
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:AnovelTb(III)ternarycomplexTb(p-BBA)_3MAAwassynthesizedwith4-benzoylbenzoicacid(p-BBA)andmethacrylicacid(MAA)asligands.ThecomplexwascharacterizedbyIR,UV-visible,thermogravimetricanalysisandfluorescencespectroscopy.Monitoredat544nm,thecomplexdisplayedwideandstrongexcitationbandat300–400nm,whichmatchedwellwiththe365nm-emittingUVchip.Thecomplexexhibitedexcellentgreenemissionat544nm(~5D_4→~7F_5transitionofTb~(3+))underanexcitationat365nm.Besides,thecomplexshowedhighthermalstability.Itsintramolecularenergytransferprocesswasfurtherdiscussed.Furthermore,thecomplexalsohadhigherfluorescencelifetime(1.38ms)andhigherquantumyield(0.372).Finally,electroluminescentpropertiesindicatedthatwhenusedtofabricateLEDwith365nmUVchip(powerefficiencyis18.6lm/W),thecomplexremaineditsfavorableopticalperformance.TheseresultsimpliedthatTb(p-BBA)_3MAAcouldbeusedasagreenphosphorforNUV-basedwhiteLED.