简介：Withpositronannihilationradiationonedimensionangular-correlationdevice,itismeasuredthatpositronannihilationradiationonedimensionangular-correlationcurvesofpolycrystalsodiumionconductorNa5Y1-xCrxSi4O12（NYCS）system.Afterelectronmomentumdistributioncurvesarenormalized,linearparametersarecalculated.TheparametersH,WandSshowthechangeofNa+ionvacancyconcentrationinNYCSseriessamples.TheresultsshowthatparametersH,WandSofonedimensionangular-correlationcurvesofthosesamplesvarygreatlywithCr2O3contents.WithCr2O3contentincreasing,HandSparametersincrease,butWdecreases,andreachesextremesatx=0.05;thenwithCr203addingcontinually,parametersHandSdecreasegradually,parameterWincreasesgradually.Thisshowsthat,inaddtiontoCr2O3,theconductivityhascloserelation

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简介：Er^3+-dopedSrBi4Ti4O15-Bi4Ti3O12(SBT-BIT-xEr^3+,x=0.00,0.05,0.10,0.15and0.20)inter-growthceramicsweresynthesizedbythesolid-statereactionmethod.Structural,electricalandup-conversionpropertiesofSBT-BIT-xEr^3+wereinvestigated.Allsamplesshowedasinglephaseoftheorthorhombicstructure.RamanspectroscopyindicatedthattheEr^3+substitutionforBi^3+atAsitesofthepseudo-perovskitelayerincreasesthelatticedistortionofSBT-BIT-xEr^3+ceramics.ThesubstitutionofBi^3+byEr^3+leadstoadecreaseofdielectriclosstanδandanincreaseofconductivityactivationenergy.Piezoelectricconstantd33wasslightlyimproved,butdielectricconstantwasdecreasedwiththeEr^3+doping.TheSBT-BIT-xEr^3+ceramicwithx=0.15exhibitstheoptimizedelectricalbehavior(d33~17pC/N,tanδ~0.83%).Moreover,twobrightgreen(532and548nm)andonered(670nm)emissionbandswereobservedunderthe980nmexcitation.Optimizedemissionintensitywasalsoobtainedwhenx=0.15fortheSBT-BIT-xEr^3+ceramic.Therefore,thiskindofceramicsoughttobepromisingcandidatesformultifunctionaloptoelectronicapplications.

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简介：以超重力场辅助燃烧合成技术制备了呈梯度分布的Y2O3-Al2O3-SiO2玻璃／Y3Al5O12陶瓷梯度复合材料。结果表明，梯度布置两种组分的原料既可防止下层熔体的喷溅，又能提高上层玻璃的透过率。该梯度材料沿超重力方向依次为YAS透明玻璃层、YAS-YAG玻璃陶瓷层和YAG陶瓷层。