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:Thesinglecrystalofthecomplex[Sc(NO3)3(H2O)2]·(15C5)hasbeenpreparedinacetonitrile.Thenewcomplexhasbeencharacterizedbyelementalanalysis,IRspectra,solubilityandmolarconductancemeasurements.ThestructureofthecomplexisdeterminedbysinglecrystalX-raydiffractionanalysis.
简介:Aseriesofnovelbluelong-lastingphosphorescencephosphorsSr6Al18Si2O37:Eu2+,RE3+(RE3+=Ho3+,Gd3+,Dy3+andPr3+)werepreparedbytheconventionalhigh-temperaturesolid-statereactioninareductiveatmosphere.TheirpropertiesweresystematicallyinvestigatedutilizingX-raydiffraction(XRD),photoluminescence,phosphorescenceandthermoluminescence(TL)spectra.ThephosphorsemittedbluelightthatwasrelatedtotheemissionofEu2+dueto5d-4ftransition.Brightbluelong-lastingphosphorescence(LLP)couldbeobservedaftertheexcitationsourcewasswitchedoff.Fortheoptimizedsample,thebluelong-lastingphosphorescencecouldlastfornearly4hinthelightperceptionofthedark-adaptedhumaneye(0.32mcd/m2).TheeffectsofRE3+ionsonphosphorescencepropertiesofthephosphorswerestudied,andtheresultsshowedthattheco-dopingofRE3+ionsgreatlyenhancedtheintensityofthepeakaround315Kwhichwasrelatedtothelonglastingphosphorescenceofthephosphorsatroomtemperatureandconsequentlyimprovedtheperformanceofthebluephosphorescencesuchasintensityandpersistenttime.
简介:EffectofLa-richrareearthoneutecticmicrostructureinA1-2%Fealloywasstudied.WhentheadditionofREissmall,a-A1phaseisintheformofcellulardendrite.WiththeincreaseoftheadditionofRE,thenucleationandgrowthofa-A1dendritearesuppressed,andeutecticAl3Fephaseisrefined.WhentheadditionofREgetsto0.6%(massfrac-tion),thesizeofeutecticAl3Feincreases.Inaddi-tion,mechanismoftheeffectofmixedREoneutecticmorphologyofA1-2%Fealloyisexplored.
简介:Differentfluxeswereusedtosynthesizelongpersistencephosphors,calciumsulfidesactivatedbyEu2+andTm3+,byconvenientsolid-statemethod.ThephosphorusingNH4Fasafluxhasgoodcrystallinityandlargeparticlesize,itsstabilityagainstwaterandotheratmosphericcomponentsisenhanced,anditsafterglowislongerandfluorescentintensityismoreintensethanthoseofthephosphorusingNH4Clasflux.TheirPLintensitiesvariedwithtimeinmoistairweremeasured,noremarkablechangewasfoundforthosepreparedwithNH4FfluxincontrastwithNH4Clasflux.SousingNH4Fasfluxisagoodmethodtoenhancethestabilityofalkalineearthsulfides.
简介:Theeffectofanexternalelectricfieldonthecrystallizationbehaviorofamorphous(Nd0.1Fe0.9)3Balloywasinvestigated.ThecrystallizationproductofNd2Fe23B3phasewasobtainedforthisamorphousalloyannealedat923Kfor300sinthepresenceofanexternalelectricfieldof300kV·m-1(50Hz);whilethecrystallizationproductsareNd1.1Fe4B4,α-Fe,andFe3Bphasesunderthesameannealingconditionexceptforfree-electricfield.Ontheotherhand,thesampleswereannealedat1023K,whichishigherthanthedecompositiontemperatureofmetastableNd2Fe23B3phase,for600s.Inthecaseofthepresenceofanexternalelectricfield,themetastableNd2Fe23B3phase,asamainphase,isstillstayedinthesample.ThisfactsuggeststhattheexternalelectricfieldenhancesthestabilizationofthemetastableNd2Fe23B3phase.Theeffectoftheexternalelectricfieldonthephaseselectionandstabilizationwasexplainedintermsofthespecificconductancedifferencebetweenthecrystallizationproducts.
简介:EffectofMnsubstitutionforFeincubicLavesZr0.1Tb0.9(Fe1-xMnx)2andY0.1Tb0.9(Fe1-xMnx)2com-poundsispresented.Similarresultsinbothsystemsareobtained:ThestructureandthemagnetismofTbFe2arebothinfluencedslightlybyasmallamountofYorZrsubstitutionforTb;Withincreasingxvalue,thelatticeconstantincreasesmonotonously;theCurietemperaturedecreaseslinearly;whilesaturationmagnetizationincreaseslinearly.ForthesmallamountofMnsubstitutionforFeinbothsystems,magnetostrictionissignificantlylargerthanthatinthepureironalloys.Thelargestmagnetostrictionof|γ‖-|γ|=2200×10-6atmagneticfieldof2×107/4πA/misobtainedforY0.1Tb0.9(Fe0.95Mn0.052.
简介:Awhitelong-lastingphosphorCa2MgSi2O7:Dy3+waspreparedbythesolid-statereaction.Astrongbandpeakedat260nmwasshownintheexcitationspectrumof578nmemission,whichmightbeattributedtotheoxygendeficiencyofthehost.Afterirradiatedwith254nmfor4min,thewhiteafterglowofthesamplecouldbeseenfor3h.Moreover,thedepthsandfrequencyfactorsoftrapcenterswerecal-culatedfromthethermo-luminescencecurveofthesample,whichindicatedthatthetrapcenterscorrespondingtothe414Kbandweremorehelpfultothelong-lastingphosphorescence.