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443 个结果
  • 简介:APt-MoO3/Ccatalyst,aimedtoeliminatetheharmfuleffectofsulfurdioxide(SCb)ontheperformanceofPtnanoparticles(NPs)forcatalysisofoxygenreductionreaction(ORR)inprotonexchangemembranefuelcells(PEMFC),isdevelopedandcharacterizedbyTEM,XRDandXPS.TheresultsrevealthatPt-MoO3/Ccatalystexhibitsnotonlyahighercatalyticactivity,butalsoabetterSO2poisoningresistanceandabetterrecoveryperformancethanthecommercialPt/Ccatalystdoes.

  • 标签: 氧还原反应 催化剂 氧化钼 质子交换膜燃料电池 PT纳米粒子 耐受
  • 简介:TheoptoelectronicandmagneticpropertiesofpureHoMnO3andHo0.67T0.33MnO3(T=La,Y)alloysinhexagonalphasearetheoreticallyinvestigatedbyusingthefirst-principlescalculations.TheinvestigationsareperformedbymeansofthedensityfunctionaltheorythroughusingthespinpolarizedgeneralizedgradientapproximationplustheHubbardpotential(SPGGA+U,Ueff=3eV).ThestudiedmaterialHoMnO3exhibitstwoindirectbandgaps:1.58eVforthespinupstateand0.72eVforthespin-downstatealongtheS–GdirectionwithintheSPGGA+Uapproximation.ItisfoundthatthebandgapofpureHoMnO3forthespin-upstateincreaseswithincreasingLaandYdopants.Theresultsshowthatallofthestudiedmaterialshavesemi-metallicbehaviorsforthespin-upstateandsemiconductingcharacterforthespin-downstate.ThesubstitutionsofLaandYforHoinHoMnO3causethestaticdielectricconstant(ε0)toincreaseinthexdirectionbuttodecreaseinthezdirection.ThecalculatedopticalconductivityspectrumofHoMnO3inalowenergyrangeisingoodagreementwiththerecentexperimentaldata.

  • 标签: 第一性原理计算 光电性能 过渡金属 III 磁性 B型
  • 简介:A New E Transition from 9+ Isomer in 144Pm NucleusANewETransitionfrom9+Isomerin144PmNucleus¥ZhangYuhu;Y.Gono;ZhaoQinz...

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  • 简介:Extractionofthein-mediumpropertiesofstrangeparticlesfromheavy-ioncollisionsisverycomplicated,sincehenucleardensityvariesintheevolutionofnucleus-nucleuscollisions.Toavoidtheuncertaintiesofthebaryonensitiesduringthestageofstrangeparticleproduction,onecaninvestigateproton-nucleuscollisionswheretheucleardensityisdefinitearoundthesaturationdensity.DynamicsofstrangeparticlesproducedintheprotoninduceduclearthereactionsnearthethresholdenergieshasbeeninvestigatedwithintheLanzhouquantumoleculardynamics(LQMD)transportmodel.Thein-mediummodificationsonparticleproductionindensenuclearmatterareconsideredthroughthecorrectionstotheelementarycrosssectionsviatheeffectivemassandhemean-fieldpotentials[1].

  • 标签: STRANGE PARTICLES In-medium
  • 简介:Nanowireshaveattractedmoreandmoreinterestinrecentyearsduetotheiruniquepropertiescomparedtobulkmaterials[1].Thequitedifferentpropertiespossessedbynanowiresaremainlycausedbytheirhighsurface-tovolumeratio[2].Behaviorsofnanowiresunderirradiationconditionshavealsoattractedintensiveattentionintheseyears[3??5].Ithasbeenproposedthatnanowiresmayberadiationresistancebecausetheirlargesurface-to-volumeratio,andmeanwhilethesurfacearetheperfectsinksfordefectscreatedintheradiationprocess[3].

  • 标签: Molecular Dynamics STUDY
  • 简介:Sweetsorghum,theworld'sfifthmostimportantcerealafterrice,corn,wheatandbarley,isaveryattractivesourceforbiomassproduction.Thisrawmaterialcomplementssugarcaneproductionandisemergingastheidealfeedforanimalsandfortheproductionofthefirst-generationofbiofuels,suchasethanolandvalue-addedchemicals.Atpresent,mostofthestudiesaboutsweetsorghumfocusonutilization(suchasethanolproduction),andthestudyofsugeraccumulationinstemarerarely.

  • 标签: SUGAR Accumlation SORGHUM
  • 简介:Parametersforthe3W1sourceatBSRFweredeterminedinboththededicatedandparasiticmodeandtheirsuitabilityforproteincrystallographybeamlineatBSRFwererealized.Itisdiscussedthatthephysicsmotivationandthedesignofthe3W1iscomparedwithsimilarexperimentalstationsattheBrazilianLightSourec(1.37Gev)andMax-IIinSweden(1.5GeV).Thephotonfluxfromthe3W1sourcdisabout2×10^11photon/smAinthewavelengthrangeof2.0-0.9Ainparasiticmodeand50-80timeshigherinthededicatedmode.Boththededicatedandparasiticmodesaresuitableformacromolecularstructureexperiments.2001ElsevierScienceB.V.Allrightsreserved.

  • 标签: BSRF 北京同步辐射装置 蛋白质 生物化学 结构分析 结晶学
  • 简介:在Alq(3)层的洞传导性上做的2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane(F4TCNQ)的效果被测量。在Alq(3)的洞唯一的设备,当前的密度在与F4TCNQ做之上在1-3数量级增加,建议做的罐头有效地提高Alq(3)的洞注射和洞运输能力。用F4TCNQ的一台器官的轻射出的设备做了Alq(3)洞注射和洞运输层,和太古的Alq(3)作为电子运输和射出的层被制作并且描绘的层。明亮的排放作为电子运输和射出的层作为洞运输层和内在的Alq(3)与做p的Alq(3)在简单OLED被完成。设备的射出的效率和亮度被插入薄电子块层在器官的层的中间限制搬运人再结合地区进一步改进。

  • 标签: 有机发光二极管 半导体技术 空穴转运层 ALQ3
  • 简介:Thispaperisconcernedwithexperimentalandnumericalresearchon3DflowpastprismaticturbinecascadeSE1050(knowninQNETnetworkasopentestcaseSE1050).Theprimarygoalwastoassesstheinfluenceoftheinletvelocityprofileontheflowstructuresintheinterbladechannelandontheflowfieldparametersatthecascadeexitandtocomparethesefindingstoresultsofnumericalsimulations.Investigationsof3Dflowpastthecascadewithnon-uniforminletvelocityprofilewerecarriedoutbothexperimentallyandnumericallyatsubsonic(M2is=0.8)andattransonic(M2is=1.2)regimeatdesignangleofincidence.Experimentaldatawasobtainedusingatraversingdevicewithafive-holeconicalprobe.Numerically,the3DflowwassimulatedbyopensourcecodeOpenFOAMandin-housecode.AnalysesofexperimentaldataandCFDsimulationshaverevealedthedevelopmentofdistinctivevortexstructuresresultingfromnon-uniforminletvelocityprofile.Originofthesestructuresresultsinincreasedlossofkineticenergyandspanwiseshiftofkineticenergylosscoefficientdistribution.Differencesfoundbetweenthesubsonicandthetransoniccaseconfirmearlierfindingsavailableintheliterature.ResultsofCFDandexperimentsagreereasonablywell.

  • 标签: 实验数据 数值模拟 三维流动 涡轮叶栅 跨音速 SE
  • 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.

  • 标签: MESOPOROUS materials Co3O4 AG CO OXIDATION
  • 简介:采用溶胶-凝胶法制备了Mn离子摩尔掺杂比.32分别为0,2%,4%,6%,8%的Ba(Ti1-xMnx)O3铁电薄膜。研究发现:当x为6%时,漏电流和矫顽场均达到最小,与未掺杂时相比,漏电流降低了约3个量级,矫顽场电场强度降低了约60%,P—E回线的矩形度增加。实验结果表明:通过适量掺杂Mn离子,可以改善BaTiO3铁电薄膜电学性能,提高铁电薄膜的极化,降低薄膜的漏电流。

  • 标签: 铁电薄膜 Ba(Ti1-xMnx)O3 掺杂 漏电流 电滞回线
  • 简介:Nanosheet(S)andnanoplate(P)γ-Al2O3weresynthesizedbysimplehydrothermalmethodsandemployedassupportsforNicatalystsinCO2methanation.BothofthenanostructuredNi/Al2O3catalystsdisplayedgoodactivity.Incomparison,theNi/Al2O3-ScatalystshowedhigherCO2conversionthantheNi/Al2O3-Pcounterpartatthereactiontemperaturerangingfrom250to400°C.ThephysicalandchemicalpropertiesofthecatalystsweresystematicallycharacterizedbyN2sorption,X-raydiffraction(XRD),highresolution-transmissionelectronmicroscopy(HR-TEM),hydrogentemperature-programmedreduction(H2-TPR)andCO2temperature-programmeddesorption(CO2-TPD)techniques.Higherspecificsurfaceareaandstrongermetal-supportinteractionswereconfirmedontheNi/Al2O3-Scatalyst,whichmayleadtosmallerparticlesizeofNinanoparticles.Moreover,theNi/Al2O3-Scatalystpossessedmoreabundantweakandmediumbasicsites,whichwouldbenefittheactivationofCO2.ThesmallerNisizeandmoresuitablebasicsitesmayrationalizethesuperioractivityoftheNi/Al2O3-Scatalyst.Besides,theNi/Al2O3-Scatalystexhibitedexcellentstabilityat325°Cfor40h.

  • 标签: ALUMINA Nickel Size Nano Interaction METHANATION