简介:混合氧化物(Ce0.6Zr0.4O2)由帮助微波的加热一起沉淀准备了的CeO2-ZrO2被用作支持经由早期湿的受精的方法与各种各样的CuO内容(0wt.%15wt.%)准备一系列CuO/Ce0.6Zr0.4O2催化剂。获得的CuO/Ce0.6Zr0.4O2样品被N2吸附,XRD,拉曼,TEM和H2-TPR技术,和他们的催化活动描绘因为公司氧化被调查。结果证明CuO/Ce0.6Zr0.4O2催化剂的活动被CuO的内容强烈影响,并且有10wt.%CuO的催化剂在公司氧化展出了最好的催化活动,它能在催化剂被归因于CuO,和高氧空缺集中的高分散和reducibility。
简介:Thesynthesisofprecursorofgreenphosphors,LaPO4:Ce,Tb,bymeansofco-precipitationwithcocurrentflowfeedwasstudied.Theeffectsofthereactiontemperature,thekindandconcentrationoftheacidinthebottomwater,andthechargingrateonthephysicalproperties,suchasparticlesize,wereinvestigated.Itisfoundthattheparticlesizeofthepowderiscontrollablebyadjustingacidityinbottomwaterandchargingrate.Thepowderwithdiametersizeof3to5μmwasobtained.ItsXRDandSEMwereanalyzed.XRDpatternsoftheas-preparedgreenphosphorpowdersdisplaythetypicalpeaksofCePO4.SEMshowsthatthemorphologyofpowdersisball-shaped.
简介:
简介:BondedtypeRE3+dopedluminescentco-polymerwassynthesizedbysolutionfreeradicalcopolymerization.Theinfluenceofchargesequence,monomersandco-polymerizedmethodonpropertiesandstructuresoftheco-polymerswasstudied.Theemissionintensityoftheco-polymersatdifferentRE3+concentrationswastested.Theresultsshowedthattheco-polymersofEu-PStandEu-PMMAbothhadwideabsorptionpeakat200-400nmandthestrongestpeakappearedat235nm.ThefluorescentintensityofEu3+dopedpolystyreneco-polymerwasstrongerthanthatofEu3+dopedPMMAcopolymer.Thecharacteristicemissionofeuropiumionswasobservedintheco-polymers.Thecopolymerdopedwithrareearthelementsshowedthe"sensitizationeffect"forthecentralions.Thebonded-typerareearthcopolymernotonlyenhancedtheenergytransferefficiency,butalsoimprovedthefluorescenceintensitybyiacreasmgtherigidityofmainandsidechain.
简介:YAG:Ce3+(Yttriumaluminumgarnet)fluorescencepowdersweresuccessfullypreparedbyco-precipitationmethodusingaluminumnitrate,yttriumnitrate,cerousnitrateasthestartingmaterialsandammoniumcarbonateasprecipitant.TheproductswerecharacterizedbyX-raypowderdiffraction,luminescencespectrometer,transmissionelectronmicroscope(TEM).TheXRDresultsshowedthattheobtainedYAG:Ce3+fluorescencepowdershadthecrystallinestructuresofYAGatcalcinationstemperatureof900oCandtheTEMresultsshowedthatthegraindiameterswereabout100nm.TheYAG:Ce3+fluorescencepowders,synthesizedbyco-precipitationmethod,hadthebestluminescencepropertywhentheCedopingamountwasx=0.06inthemolecularformulaofY3-xCexAl5O12,thecalcinationstimewas2handthecalcinationstemperaturewas1000°C.
简介:Eu-activatedCaMoO4phosphorswereco-precipitatedinanaqueoussolution,andNH3·H2O,NH4HCO3and(NH2)2COaspre-cipitatingaidagentswerecomparedbasedonthemorphologyandparticlesizedistributionofthephosphorsamples.Sm3+assensitizerionwasinvestigatedontheluminescenceofCaMoO4:Eu,anditcouldstrengthenthe406nmabsorptionofthisphosphor.Atlast,thescheeliteCaMoO4:EuandwolframiteZnMoO4:Euwereselectedtocomparetheirhostabsorption.TheresultshowedthatthescheelitemolybdatehostexhibitedstrongerUVabsorptionthanwolframiteone.
简介:TheSmBaCuMO5+δ(M=Fe,Co,Ni)(SBCM)powdersweresynthesizedbythecitratesol-gelmethodandthepowdersweresinteredtoceramicpellets.ThepowdersandsinteredceramicpelletswerecharacterizedwithXRD,TEMandSEMmeasurements.ThecathodecatalyticperformancesofSBCMceramicpelletsforammoniasynthesiswerestudiedfromwethydrogenanddrynitrogenatatmosphericpressureandlowtemperature,usingSBCMceramicpelletsascathode,Nafionprotonexchangemembraneaselectrolyte,Ni-Ce0.8Sm0....
简介:InordertoimproveandstabilizethemagneticpropertiesofnanocompositeNd2Fe14B/α-Femagneticalloysbyacompositionaladjustment,smallamountofDyand/orCowasaddedtoNd9Fe84B7alloys.DTAanalysisontheamorphousofthealloystookplaceasthesoftmagneticphaseswerecrystallized,andthenthehardmagneticNd2Fe14Bwasprecipitatedfromthem.Whileα-Feandametastable1:7(TbCu7-type)phasewereformedsimultaneouslyinDyandCo-freealloys,theywerecrystallizedseparatelyatdifferenttemperaturesafterDyorCowasadded.ThisphaseseparationoccurredmoreclearlyintheDy-treatedalloysandtheothersoftmagneticphaseFe3BwasalsostabilizedbyDyand/orCo.The1:7phasethatwasstabilizedbyDyand/orCowasnoteliminatedat700℃,decreasingmagneticpropertiesofthealloys.Itwaseventuallydisappearedabove725℃,butFe3Bwasnoteliminatedevenat750℃whenDywasaddedmorethan0.5at%orCowasaddedmorethan2.0at%.AmountofNd2Fe14BinthealloystendedtoincreaseasDyadditionincreased,whereasCoadditiondidnotleadtoanyappreciablechangeintheratioofα-FeandNd2Fe14B.Moreover,DyadditionapparentlyincreasedcoercivityofanalloywhileCoadditionhadabeneficialeffectonremanence.ThegrainsintheDytreatedalloyswereusuallyfinerthanthoseintheCo-treatedalloys.Thegrainsizeofbothα-FeandNd2Fe14Binthealloysexhibitingmr≥0.72wasintherangeof20~40nmorevenlarger50nm,whichislargerthanthetheoreticaloptimumsize(~10nm).TypicalmagneticpropertiesobtainedfromaNd7.5Dy1.5Fe82.5Co1.5B7alloyannealedfor12minat725℃wereiHc=4.85kOe,Br=11.32kG,(BH)max=15.73MGOe,andmr=0.73.
简介:SinglephaseofBa1-xMgAl10O17:xEu2+(0.02≤x≤0.14)phosphorswasfirstsuccessfullypreparedbyco-precipitationinaqueousmediumwitha'reversestrike'method,usingoxalicacidandammoniatogetherasprecipitants.Completelycrystallizedphosphorswereobtainedat1300℃,whichis300℃lowerthanthetemperatureofsolid-statereaction.TheirphotoluminescencewasinvestigatedunderUVandVUVregion,respectively.TheemissionspectraofBa1-xMgAl10O17:xEu2+samplesexcitedby254or147nmshowedacharacteristicwidebandwiththepeakcentredatabout450~454nm.Optimumemissionintensityreachedatx=0.1andthenconcentrationquenchingoccurred.Thesynthesizedphosphorshows10%higheremissionintensitythanthatpreparedbysolid-statereaction.
简介:Er/Ybco-dopedborate-silicateglasseswithvariousYbconcentrationswerefabricatedbyhigh-temperaturesolid-reactionmethod.Thephotoluminescencespectraaround1.55μmandthevisibleupconversionspectraweremeasured.TheradiativelifetimeofEr-4I13/2,com-paredwiththemeasuredone,wasobtainedbyJudd-Ofelttheorybasedontheabsorptionspectra.ArateequationmodelforEr/Ybco-dopedsystemhasbeenestablishedbasedonthedataobtainedfromthemeasurements,includingtheabsorptionandemissio...
简介:TheLa-CosubstitutedSr_(1–x)La_xFe_(12–x)Co_xO_(19)(x=0–0.5)ferriteswithappropriateBi_2O_3additivewerepreparedbyconventionalsinteringmethodandmicrowavesinteringmethodatlowsinteringtemperaturescompatiblewithLTCC(lowtemperatureco-firedceramics)systems,andtheirsinteringbehaviorwaschieflyinvestigated,includingthecrystalstructure,saturationmagnetizationMs,magneticanisotropyfieldHa,intrinsiccoercivityHci,andCurietemperatureTC.ExperimentresultsclearlyshowedthatthepureM-typecrystalphasewassuccessfullyobtainedwhentheLa-Cosubstitutionamountxdidnotexceed0.3.However,thesingleM-typephasestructuretransformedtomultiphasestructurewithfurtherincreasedx,wheretheM-typephasecoexistedwiththenon-magneticphasesuchasα-Fe_2O_3phase,La_2O_3phase,andLaCoO_3phase.AppropriateLa-CosubstitutionimprovedtheMs(〉62emu/g),Ha(〉1400kA/m),andHci(〉320kA/m)fortheferriteswithxvaryingfrom0.1to0.3,buttheTCdecreasedwithincreasingsubstitutionamount.Moreover,themicrowavesinteredferritescouldprovidelargerHciandsimilarMscomparedwiththeconventionalsinteredferrites.
简介:La公司代替了M类型钡铁酸盐(欺骗)由传统的稳固的状态被准备在低温度(1173K)的方法和sintered。X光检查衍射(XRD),扫描电子显微镜学(SEM)和颤动的样品磁强计(VSM)被采用在样品的结构和磁性上调查La公司的影响。由在为在空中的6h的1173K的sintering,有Ba(LaCo)xFe122xO19(x=0.00.5)的化学作文的单个阶段M类型钡铁酸盐被形成。M-H曲线证明钡铁酸盐的磁性被La公司替换显然完成。浸透磁化(女士)和coercivity(Hc)分别地到达了65.15Am2/kg和4165Oe的最大的价值。这行为被归因于La公司替换和粒子尺寸的地点。SEM表明铁酸盐粒子的形状被La公司替换影响。
简介:TheeffectofrapidsolidificationonstructureandelectrochemicalperformanceoftheLaNi4.5Co0.25Al0.25hydrogenstoragealloywasinvestigatedbyX-raypowderdiffractionandasimulatedbatterytest,includingmaximumcapacity,cyclingstability,self-discharge,andhigh-ratedischargeability(HRD).Allthemelt-spunalloysweresingle-phasewiththeCaCu5-typestructure(spacegroupP6/mmm).Incomparisontotheas-castalloy,therapidlyquenchedalloysmanifestedanimprovedhomogeneityofcompositionandexpandedlatticeparameters.Theelectrochemicalmeasurementsshowedthattheactivationproperty,cyclingstabilityandself-dischargeofthealloyelectrodeswerealsoimprovedfortherapidsolidifiedalloys.TheHRDoftheas-castalloywasbetterthanthoseofalltherapidlysolidifiedalloys.Asthequenchingrateincreased,theHRDandexchangecurrentdensityfirstdecreasedandthenincreased.