简介:ThedosimetricphosphorsLi_3PO_4:M(M=Tb,Cu)wereproducedbymodifiedsolid-statemethod.ThestructuralandmorphologicalcharacterizationwascarriedoutthroughX-raydiffraction(XRD)andscanningelectronmicroscope(SEM).Additionally,thephotoluminescence(PL),thermoluminescence(TL)andopticallystimulatedluminescence(OSL)propertiesofpowderLi_3PO_4dopedwithTbandCuwerestudied.ItisadvocatedthatLi_3PO_4:CuphosphornotonlyshowshigherOSLsensitivity(25timesormore)butalsogivesfasterdecayinOSLsignalsthanthatofLi_3PO_4:Tb~(3+)phosphor.Theminimumdetectabledose(MDD)ofLi_3PO_4:M(M=Tb,Cu)phosphorsisfoundtobe21.69×10~(-3)and3.33×10~(-6)J·kg~(-1),respectively.InOSLmode,phosphorshowslineardoseresponseintherangeof0.02-20.00J·kg~(-1).InTLmode,sensitivityofLi_3PO_4:CuphosphorismorethanthatofLi_3PO_4:Tbphosphor.Thekineticsparameterssuchasactivationenergyandfrequencyfactorsweredeterminedbypeakshapemethod,andphotoionizationcrosssectionsofpreparedphosphorwerecalculated.
简介:InordertoimprovetheelectrochemicalcyclestabilityofLa-Mg-Nisystem(PuNi3-type)hydrogenstoragealloy,NiinthealloyswaspartiallysubstitutedbyM(M=Cu,Al,Mn).AnewLa-Mg-NisystemelectrodealloysLa0.7Mg0.3Ni2.55-xCo0.45Mx(M=Cu,Al,Mn;x=0,0.1)werepreparedbycastingandrapidquenching.Theeffectsofelementsubstitutionandrapidquenchingonthemicrostructuresandelectrochemicalperformancesofthealloyswereinvestigated.TheresultsbyXRD,SEMandTEMshowthatthealloyshaveamultiphasestructure,includingthe(La,Mg)Ni3phase,theLaNi5phaseandtheLaNi2phase.Therapidquenchingandelementsubstitutionhaveanimperceptibleinfluenceonthephasecompositionsofthealloys,butbothchangethephaseabundanceofthealloys.Therapidquenchingsignificantlyimprovesthecompositionhomogeneityofthealloysandmarkedlydecreasesthegrainsizeofthealloys.TheCusubstitutionpromotestheformationofanamorphousphaseintheas-quenchedalloy,andareversalresultbytheAlsubstitution.Theelectrochemicalmeasurementindicatesthattheelementsubstitutiondecreasesthedischargecapacityofthealloys,whereasitobviouslyimprovesthecyclestabilityofthealloys.ThepositiveinfluenceofelementsubstitutiononthecyclelifeofthealloysisinsequenceAl>Cu>Mn,andnegativeinfluenceonthedischargecapacityisinsequenceAl>Mn>Cu.Therapidquenchingsignificantlyenhancesthecyclestabilityofthealloys,butitleadstoadifferentextentdecreaseofthedischargecapacityofthealloys.
简介:通过氙灯和热氧人工加速老化研究了191#不饱和聚酯玻璃钢老化后力学性能的变化规律,并对玻璃钢表面形貌和失光率进行了表征。结果表明:氙灯老化后,弯曲强度随老化时间增加先增大后减小,而层间剪切强度则呈下降趋势,老化1800h后弯曲和剪切强度的保持率分别为92%和53%。玻璃钢表面失光率大,有明显的裂纹产生。70%热氧老化,表面形貌保持完好,树脂的后固化和物理老化效应导致玻璃钢的力学强度明显增大,3600h后弯曲和剪切强度增大到老化前强度的107%和150%。光和热的联合作用是玻璃钢表面和界面老化破坏的主要因素。玻璃钢具有较好的耐热氧老化性能。
简介:FluorescenceandcofluorescencepropertiesofTb(Ⅲ)solidcomplexeswerestudiedusingpyromelliticacid(PMA)asligandandfluorescenceinertionsasdopingelements.Thecofluorescenceenhancement,aresultofligandsensitizedfluorescence,wasobservedinTb(Ⅲ)solidcomplexesdopedwithfluorescentinertionsLa(Ⅲ),Gd(Ⅲ),Ca(Ⅲ),andSr(Ⅲ).Theeffectofthetypeandcontentofdopingelementsonfluorescenceenhancementwasstudied,andoptimumconditionsweredetermined.TheresultsshowthatGd(La,Ca,Sr)hasclearcofluorescenceeffectinsolidcomplexTb-M-PMAsystem,andinpresentwork,rareearthcomplexfluorescentpowderthatemitsbrightgreenfluorescenceatultravioletexcitationwasobtained,whichhadpotentialapplicationasfluorescentanti-counterfeitink.
简介:采用BP神经网络对聚酯玻璃钢氙弧灯加速老化的弯曲寿命进行了预测。通过对聚酯及其玻璃钢的人工氙弧灯加速老化,测试其不同老化时间的弯曲强度,对弯曲强度与老化时间进行BP神经网络的建模分析,借助MATLAB软件对聚酯玻璃钢的使用寿命分别进行分析与预测,并采用最小二乘法对所预测的结果进行了对比。结果表明:在以弯曲强度达到初始强度值的一半作为失效条件下,聚酯的氙灯老化寿命为813d,含填料玻璃钢老化寿命为1031d,无填料玻璃钢老化寿命为1065d,说明BP神经网络可以预测玻璃钢的老化寿命,预测结果与最小二乘法预测结果误差不大于8%,而且预测结果与该材料性能的实际情况相符。
简介:Basedonclustervariationmethod(CVM)andnaturaliterationmethod(NIM),order-disorderphasetransitionintheintercalationcompoundsM1/2TiS2issimulatedbycomputer.Thefavorableconditions,underwhich3a0×a0superstructureisformed,aregiven,andtheresultsareingoodagreementwiththeexperimentsandtheoreticalcalculations.TherelationshipbetweencriticaltemperatureandM-ion-vacancyinteractionparameterislinear.
简介:1IntroductionTherareearthcobaltalloyshavethepotentialformakingthemagneticandmagnetoopticalmaterials.Sofar,therareearthcobaltalloyfilmsaresubstantiallyproducedbysputteringorvacuumplating.Ifsuchfilmsarepreparedbyelectrodepositioninstead,productionefficiencywouldbeimprovedandthecompositionofthealloycouldbecontrolled.Becausetheoxidationreductionpotentialsofrareearthelementsareverynegative,organicsolventsmaybeusedaselectrolyticmedia.ElectrodepositionofGdCoandSmCoinorganicsolutionshasbeenreporte...
简介:利用聚合物泡沫采用压力浸渗铸造工艺制备开孔泡沫铝。所制备的泡沫铝能够很好地复制聚合物泡沫的几何尺寸。开孔泡沫铝的强度比闭孔泡沫铝的低很多,从而得到更多的应用。添加陶瓷颗粒可以改善泡沫铝的力学性能。本研究中,向AC3A铝合金中添加SiC颗粒得到复合材料泡沫。在复合材料泡沫中,SiC颗粒嵌入在合金基体中及孔筋表面。高体积分数的陶瓷颗粒使合金泡沫铝的压缩强度、能量吸收、显微硬度增大。这些性能的改善归结为于泡沫铝的结构改变以及SiC颗粒存在于结点和孔筋处而引起的强度增加。
简介:LayeredcathodematerialLiCo1/3Ni1/3Mn1/3O2wassynthesizedbyPechiniprocess,andinvestigatedusingX-raydiffraction(XRD),scanningelectronmicroscopy(SEM)andgalvanostaticcharge/dischargecycling.Thesampleiswell-crystallizedandhasaphase-purea-NaFeO2structure.Theparticlesizesareuniform,anddistributedintherangeof20-200nm.TheinitialdischargecapacityoftheLi/LiCo1/3Ni1/3Mn1/3O2cellwasabout149mAh·g-1whenitwascycledatavoltagerangeof4.5-2.3Vwithaspecificcurrentof0.25mA.Theresultisbetterincomparisonwithsolid-statesolutionmethod.Thesyntheticprocedurewasdiscussed.Threemajorreactions:chelation,esterification,andpolymerizationsuccessivelyoccurred.
简介:LaCrO_3的nano粉末被一条大音阶的第五音胶化线路准备。从350~550K的LaCrO_3nano粉末的热能力被DSC方法测量并且是表示了:C_(p(LaCrO3))(±0.112)=166.844-8.500x10~(-3)T-1.022x10~6T~(-2)(J/(摩尔·K))(350-550K)。一个EMF测量集会为流电的房间作为电解质与CaF_2被开发。可逆房间的FrommeasuredEMF数据,(-)磅,La_2O_3,LaF_3,|CaF_2|O_2(1atm),LaF_3,LaCrO_3,Cr_2O_3,磅(+),和吉布斯的相关价值释放的O_2(1atm)精力,吉布斯LaCrO_3的形成的免费精力从700~885K被计算:ΔG_(f,LaCrO3)~Θ=-1555.364+0.354T(kJ/mol)(700-885K)。并且免费精力从简单氧化物La_2O_3andCr_2O_3反应改变的吉布斯是打算的是:ΔG_(f,公牛(LaCrO3))~Θ=-94.758+8.530x10~(-2)T(kJ/mol)(700-885K)。
简介:EmployingLi2CO3,NiO,Co3O4,andMnCO3powdersasstartingmaterials,Li[Ni1/3Co1/3Mn1/3]O2wassynthesizedbysolid-statereactionmethod.Variousgrindingaidswereappliedduringmillinginordertooptimizethesynthesisprocess.Aftersuccessiveheattreatmentsat650and950℃,thepreparedpowderswerecharacterizedbyX-raydiffraction(XRD)analysis,scanningelectronmicroscopy,andtransmissionelectronmicroscopy.Thepowderspreparedbyaddingsalt(NaCl)asgrindingaidexhibitaclearR3mlayerstructure.ThepowdersbyothergrindingaidslikeheptaneshowsomeimpuritypeaksintheXRDpattern.Theformerpowdersshowauniformparticlesizedistributionoflessthan1μmaveragesizewhilethelattershowsawidedistributionrangingfrom1to10μm.EnergydispersiveX-ray(EDX)analysissshowthattheratioofNi,Co,andMncontentinthepowderisapproximately1/3,1/3,and1/3,respecively.TheEDXdataindicatenoincorporationofsodiumorchlorineintothepowders.Charge-dischargetestsgaveaninitialdischargecapacityof160mAh·g-1forthepowderswithNaCladditionwhile70mAh·g-1forthepowderswithheptane.
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简介:有5-8nm的尺寸的做Eu的GaOOHnanoparticles被热水的方法作为表面活化剂用钠dodecylbenzenesulfonate(SDBS)准备。做Eu的-Ga2O3和-Ga2O3被退火进一步制作GaOOH:Eu然后由X光检查衍射(XRD)描绘了,传播电子显微镜学(TEM)和光致发光(PL)。TEM结果显示出那monodisperse做Eu3+的GaOOHnanoparticles形式然后变换进通过退火的做Eu3+的-Ga2O3和-Ga2O3GaOOH:在600和900点的Eunanoparticles?????????????????@