简介：Thefullpotentiallinearizedaugmentedplanewave(FLAPW)methodisusedtostudythecrystalstructureandelectronicstructurepropertiesofPbFeo.5Nbo.5O3(PFN).Theoptimizedcrystalstructure,densityofstates,bandstructureandelectrondensitydistributionhavebeenobtainedtounderstandtheferroelectricbehaviourofPFN.TheanalysisresultofthedensityofstatesshowsthereisanobviouschangeofNbdstatesintheparaelectric-to-ferroelectricphasetransition.ThepolarizationresultshowsthatthecontributiontoferroelectricityofNbatomsislargerthanthatofFeatoms.InferroelectricphasethereisahybridizationofFed-OpandNbd-OpinferroelectricPFN.Thisisconsistentwiththeresultoftheelectronicbandstructure.Thishybridizationisresponsibleforthetendencytoitsferroelectricity.

简介：Inthisstudy,nanocrystallineCo–Ni–MgferritepowderswithcompositionCo0.5Ni0.5-xMgxFe2O4aresuccessfullysynthesizedbytheco-precipitationmethod.Asystematicinvestigationonthestructural,morphologicalandmagneticpropertiesofun-dopedandMg-dopedCo–Niferritenanoparticlesiscarriedout.Thepreparedsamplesarecharacterizedusingx-raydiffraction（XRD）analysis,Fouriertransforminfraredspectroscopy（FTIR）,fieldemissionscanningelectronmicroscopy（FESEM）,andvibratingsamplemagnetometry（VSM）.TheXRDanalysesofthesynthesizedsamplesconfirmtheformationofsingle-phasecubicspinelstructureswithcrystallitesizesinarangeof32nmto36nm.ThelatticeconstantincreaseswithincreasingMgcontent.FESEMimagesshowthatthesynthesizedsamplesarehomogeneouswithauniformlydistributedgrain.TheresultsofIRspectroscopyanalysisindicatetheformationoffunctionalgroupsofspinelferriteintheco-precipitationprocess.ByincreasingMg2+substitution,roomtemperaturemagneticmeasurementshowsthatmaximummagnetizationandcoercivityincreasefrom57.35emu/gto61.49emu/gand603.26Oeto684.11Oe（1Oe=79.5775A·m-1）,respectively.ThehighervaluesofmagnetizationMsandMrsuggestthattheoptimumcompositionisCo0.5Ni0.4Mg0.1Fe2O4thatcanbeappliedtohigh-densityrecordingmediaandmicrowavedevices.

简介：

简介：

简介：PalladiumcatalystsaresupportedonTiO2,ZrO2,Al2O3,Zr0.5Al0.5O1.75andTiO2-Zr0.5Al0.5O1.75preparedbyco-precipitationmethod,respectively.CatalyticactivitiesformethaneandCOoxidationareevaluatedinagasmixturethatsimulatedtheexhaustfromlean-burnnaturalgasvehicles(NGVs).Pd/TiO2-Zr0.5Al0.5O1.75performsthebestcatalyticactivityamongthetestedfivecatalysts.ForCH4,thelight-offtemperature(T50)is254℃,andthecompleteconversiontemperature(T90)is280℃;forCO,T50is84℃,andT90was96℃.Varioustechniques,includingN2adsorption-desorption,X-raydiffraction(XRD),H2-temperature-programmedreduction(H2-TPR),X-rayphotoelectronspectroscopy(XPS),andscanningelectronmicroscopy(SEM)areemployedtocharacterizetheeffectofsupportsonthephysicochemicalpropertiesofpreparedcatalysts.N2adsorption-desorptionandSEMshowthatTiO2-Zr0.5Al0.5O1.75expressesuniformnano-particlesandlargemeso-porediametersof26nm.H2-TPRandXRDindicatethatPdOiswelldispersedonthesupportsandstronglyinteractedwitheachother.TheresultsofXPSshowthattheelectrondensityaroundPdOandtheproportionofactiveoxygenonTiO2-Zr0.5Al0.5O1.75aremaximaamongthefivesupports.

简介：

简介：Pureandneodymium-dopedgadoliniumcalciumoxoboratecrystalsofhighqualityweregrownbytheCzochralskimethod.Theorientationofcrystalwaspreciselydetermined,andthesamplesformeasurementswereprepared.Throughsynchrotronx-raytopographyandhigh-resolutionx-raydiffractometry,thetwinstructurewasdiscovered.Somepropertiessuchasthefigureofmeritvalue,anddielectric,piezoelectric,andelasticconstantsweremeausuredalongwithadiscussionoftheanisotropyofthelaserproperties.

简介：粉状的LiCr0.35Mn0.65O2的电的传导性在温度范围在高压力下面被测量直到26.22GPa由使用一个钻石铁砧房间的300413K。电导率和激活热含量在5.36GPa和21.66GPa不连续地变化，这被发现。在压力范围1.105.36GPa，压力增加激活热含量并且减少散布的搬运人，它最后导致传导性增加。在压力范围6.3221.66GPa和22.6026.22GPa，有压力增加的激活热含量减少，它有积极贡献到电的电导率增加。二导致压力的结构的阶段转变被发现由在原处在高压力下面X光检查衍射，它导致电导率和激活热含量的不连续的变化。

简介：InsituhighpressureenergydispersiveX-raydiffractionmeasurementsonlayeredperovskite-likemanganateCa3Mn2O7underpressuresupto35GPahavebeenPerformedbyusingdiamondanvilcellwithsynchrotronradiation.Theresultsshowthatthestructureoflayeredperovskite-likemanganateCa3Mn2O7isunstableunderpressureduetotheeasycompressionofNaCl-typeblocks.ThestructureofCa3Mn2O7underwenttwophasetransitionsunderpressuresintherangeof0-35GPa.Onewasatabout1.3GPawiththecrystalstructurechangingfromtetragonaltgoorthorhombic.Theotherwasatabout9.5GPawiththecrystalstructurechangingformorthorhombicbacktoanothertetragonal.

简介：

简介：磁铁矿(Fe3有不同尺寸和形状的O4)nanoparticles被热分解方法综合。二条途径，非注射一个壶和热注射的方法，被设计详细调查生长机制。nanoparticles的尺寸和形状被调整先锋集中和持续时间时间决定，这被发现，它能好在我们的合成系统基于LaMer模型由机制解释了。monodisperseFe3O4nanoparticles从5nm有一条吝啬的直径到16nm，和形状进化从对球形三角形、立方。磁性是尺寸依赖者，和Fe3在关于在房间温度和最大的浸透磁化的5nm展览superparamagnetic性质的小尺寸的O4nanoparticles来临到78emu/g，而Fe3O4nanoparticles当直径增加到大约16nm时，开发铁磁性的性质。

简介：我们在Mn50Ni40SnSbx(x=1，2，3，和4)合金。所有准备样品在房间温度与空间组一起展出B2类型结构。Sb的替换增加原子价电子集中并且减少联合起来的房间体积。作为结果，当x增加，magnetostructural转变向更高的温度很快变。在在不同磁场变化下面的磁性的熵的变化在这转变附近被探索。等温的磁化曲线展出典型metamagnetic行为，显示magnetostructural转变能被一个磁场导致。悦耳的martensitic转变和磁性的熵变化建议那Mn50Ni40SnSbx合金是应用在的吸引人的候选人固态制冷。

简介：Synthesis,structureandmagneticpropertiesofRudopedperovskitestructuredmanganiteLa0.5Sr0.5MnO3wereinvestigatedexperimentally.Ahydrothermalmethodwasusedforthepreparationofthesamples.Ahigh-temperatureannealingprocesswasalsoemployedtomakeacomparison.AslightlyenhancementoftheunitcellvolumewasobservedwiththeincreaseofRuconcentration.Scanningelectronmicroscopyshowsthatthematerialsaremadeupofcube-shapedparticleswithdimensionofseveralmicrometers.Importantly,itisfoundthatboththeCurietemperatureTCandsaturationmomentcanbereducedbyRudoping.ThevalueofcoercivefieldisnotaffectedbytheintroductionofRu.

简介：COandformaldehyde(HCHO)oxidationreactionswereinvestigatedovermesoporousAg/Co3O4catalystspreparedbyone-pot(OP)andimpregnation(IM)methods.Itwasfoundthattheone-potmethodwassuperiortotheimpregnationmethodforsynthesizingAg/Co3O4catalystswithhighactivityforbothreactions.ItwasalsofoundthatthecatalyticbehaviorofmesoporousCo3O4andAg/Co3O4catalystsforthebothreactionswasdifferent.AndtheadditionofsilveronmesoporousCo3O4didnotalwaysenhancethecatalyticactivityoffinalcatalystforCOoxidationatroomtemperature(20C),butcouldsignificantlyimprovethecatalyticactivityoffinalcatalystforHCHOoxidationatlowtemperature(90C).Thehighsurfacearea,uniformporestructureandtheprettygooddispersiondegreeofthesilverparticleshouldberesponsiblefortheexcellentlow-temperatureCOoxidationactivity.However,forHCHOoxidation,theadditionofsilverplayedanimportantroleintheactivityenhancement.AndthesilverparticlesizeandthereducibilityofCo3O4shouldbeindispensableforthehighactivityofHCHOoxidationatlowtemperature.

简介：通过Cu纳米颗粒掺杂制备了Li[（Ni0.6Co0.2Mn0.2）1-xCux]O2三元正极材料,并通过调节Cu的掺杂量,讨论了Cu的掺入对Li[（Ni0.6Co0.2Mn0.2）1-xCux]O2三元正极材料晶体结构、表面形貌、电化学性能和循环性能等一系列性能的影响,铜掺杂量为x=0.01时,在0.2C倍率下的首次放电比容量达到了219.1mAh/g,经过50次充放电循环之后,剩余比容量为115.4mAh/g。最终结果为Li[（Ni0.6Co0.2Mn0.2）1-xCux]O2中Cu的掺入量为x=0.01时,所得正极材料的电化学性能和循环性能最为优异。

简介：CO2methanationhasbeenahottopicbecauseofitsimportantapplicationinthespacecraftandpotentialutilizationofcarbondioxide.Nickelcatalystisactiveforthisreaction.However,itsactivitystillneedstobeimproved.Dielectricbarrierdischarge(DBD)plasma,initiatedatambientconditionandoperatedat~150°C,hasbeenemployedinthisworkfordecompositionofnickelprecursortoprepareNi/MgAl2O4.Theplasmadecompositionresultsinhighdispersion,uniquestructure,enhancedreducibilityofNiparticlesandpromotedcatalyst-supportinteraction.AnimprovedactivityofCO2methanationwithahigheryieldofmethanehasbeenachievedovertheplasmadecomposedcatalyst,comparedtothecatalystpreparedthermally.Forexample,themethaneyieldoftheplasmapreparedcatalystis71.8%at300°Cbutitis62.9%overthethermalpreparedcatalyst.ThecatalystcharacterizationconfirmedthatCO2methanationovertheDBDplasmapreparedcatalystfollowspathwayofCOmethanation.

简介：

简介：Nanostructuredγ-Al2O3withhighsurfaceareaandmesoporousstructurewassynthesizedbysol-gelmethodandemployedascatalystsupportfornickelcatalystsinmethanereformingwithcarbondioxide.ThepreparedsampleswerecharacterizedbyXRD,N2adsorption-desorption,TPR,TPO,TPH,NH3-TPDandSEMtechniques.TheBETanalysisshowedahighsurfaceareaof204m2g-1andanarrowpore-sizedistributioncenteredatadiameterof5.5nmforcatalystsupport.TheBETresultsrevealedthatadditionoflanthanumoxidetoaluminumoxidedecreasedthespecificsurfacearea.Inaddition,TPRresultsshowedthatadditionoflanthanumoxideincreasedthereducibilityofnickelcatalyst.Thecatalyticevaluationresultsshowedanincreaseinmethaneconversionwithincreasinglanthanumoxideto3mol%andfurtherincreaseinlanthanumcontentdecreasedthecatalyticactivity.TPOanalysisrevealedthatthecokedepositiondecreasedwithincreasinglanthanumoxideto3mol%.SEMandTPHanalysesconfirmedtheformationofwhiskertypecarbonoverthespentcatalysts.AdditionofsteamandO2todryreformingfeedincreasedthemethaneconversionandledtocarbonfreeoperationincombinedprocesses.

简介：Inthiswork,theinfluenceofCO2onthestructuralvariationandcatalyticperformanceofNa2WO4/Mn/SiO2foroxidativecouplingofmethanetoethylenewasinvestigated.ThecatalystwaspreparedbyimpregnationmethodandcharacterizedbyXRD,RamanandXPStechniques.AppropriateamountofCO2inthereactantgasesenhancedtheformationofsurfacetetrahedralNa2WO4speciesandpromotedthemigrationofOinMOx,Na,Wfromthecatalystbulktosurface,whichwerefavorableforoxidativecouplingofmethane.WhenthemolarratioofCH4/O2/CO2was3/1/2,enrichedsurfacetetrahedralNa2WO4speciesandhighsurfaceconcentrationofOinMOx,Na,Wweredetected,andthenhighCH4conversionof33.1%andhighC2H4selectivityof56.2%wereobtained.WithfurtherincreaseofCO2inthereagentgases,thecontentofactivesurfacetetrahedralNa2WO4speciesandsurfaceconcentrationofOinMOx,Na,Wdecreased,whilethatofinactivespecies(MnWO4andMn2O3)increaseddramatically,leadingtolowCH4conversionandlowC2H4selectivity.ItcouldbespeculatedthatNa2WO4crystalwastransformedintoMnWO4crystalwithexcessiveCO2addedunderthereactionconditions.PretreatmentofNa2WO4/Mn/SiO2catalystbymoderateamountofCO2beforeOCMalsopromotedtheformationofNa2WO4species.

简介：CuFe2O4network,preparedviatheelectrostaticspraydepositiontechnique,withhighreversiblecapacityandlongcyclelifetimeforlithiumionbatteryanodematerialhasbeenreported.Thereversiblecapacitycanbefurtherenhancedbycoatinghighelectronicconductivepolypyrrole（PPy）.Atthecurrentdensityof100mA·g-1.Li/CuFe2O4electrodedeliversareversiblecapacityof842.9mAh·g-1whilethereversiblecapacityofLi/PPy-coatedCuFe2O4electrodeincreasesupto1106.7mAh-g’.Ahighcapacityof640.7mAhg"1fortheLi/PPy-coatedCuFe2O4electrodeismaintainedincontrastof398.9mAh·g-1forCuFe2O4electrodeafter60cycles,whichdemonstratesgoodelectrochemicalperformanceofthecompositeduetotheincreaseofelectronicconductivity.Theelectrochemicalimpedancespectroscopy（EIS）furtherrevealsthattheLi/PPy-coatedCuFe2O4electrodehasalowerchargetransferresistancethantheLi/CuFe2C>4electrode.