学科分类
/ 25
500 个结果
  • 简介:TiO2@ZrO2@Y2O3:有coremultishell结构的Eu3+合成粒子通过layer-by-layer(LBL)的联合被综合自己组装方法和一个solgel过程。获得的样品与扫描电子被描绘显微镜学(SEM),传播电子显微镜学(TEM),X光检查光电子光谱学(XPS),X光检查衍射(XRD),和荧光spectrophotometry。结果证明合成粒子有coremultishell结构,球形的形态学,和狭窄的尺寸分布。TiO2核心上的ZrO2层的存在能有效地阻止在TiO2核心和Y2O3壳之间的反应;为在在TiO2@ZrO2@Y2O3的TiO2核心和Y2O3壳之间的反应的温度:Eucoremultishell黄磷能被300提高

  • 标签: 光致发光特性 二氧化钛 氧化锆 铕核 Y2O3 纳米TiO2
  • 简介:ZrO2nanopowdersbasedstearicacidphasechangematerials(PCMs)werepreparedbyhigh-energymilling.Theconceptofheatcapacityfactor(HCF)wasusedtoanalyzethethermalpropertiesofthematerials.TheheatstoragepropertyofPCMs,containingthesamecontentofstearicacid(23%bymass)inthestartingmaterialsbutsynthesizedbydifferenttechnicalprocesses,wasinvestigatedbyusingHCF.Itwasfoundthattherewerevastinfluencesofdifferentdispersantsontheheatcapacity.Thesamplespreparedwithchloroformprovidedthebestheatstorageabilityinallsamplestested.

  • 标签: 相变材料 纳米粉体 硬脂酸 氧化锆 基础研究 蓄热性能
  • 简介:ThreeseriesofCeO2/CuOsampleswerepreparedbyimpregnationmethodandcharacterizedbyXRD,N2adsorption-desorption,temperatureprogrammedreduction(TPR),XPSandTEMtechniques.IncomparisonwiththesamplespreparedwithCuOasinitialsupport,thesampleswithCu(OH)2asinitialsupporthavehigherreducibilitiesandsmallerrelativeTPRpeakareas,andalsolargerspecificsurfaceareasatcalcinationtemperaturesof400℃–600℃.Asaresult,Cu(OH)2isbetterthanCuOasinitialsupportforpreferentialoxidationofCOinexcessH2(CO-PROX).Thebestcatalyticperformancewasachievedonthesamplecalcinedat600℃andwithanatomicratioofCe/Cuat40%.XPSanalysesindicatethatmoreinterfacelinkagesCe-O-Cucouldbeformedwhenitwascalcinedat600℃.AndtheatomicratioofCe/Cuat40%ledtoaproperreducibilityforthesampleasillustratedbytheTPRmeasurements.

  • 标签: 氧化铜催化剂 选择性氧化 氧化铈 支护效果 二氧化碳 程序升温还原
  • 简介:Anewmicromechanicsconstitutivemodelforpuredilatanttransformationplasticityofstructureceramicsisproposedinthispaper.Basedonthethermodynamics,micromechanicsandmicroscalet→mtrans-formationmechanismanalysisoftheTZPandPSZZrO2-containingceramics,ananalyticexpressionsoftheHelmholtzandcomplementaryfreeenergyoftheconstitutiveelementforthecaseofpuredilatanttransforma-tionisderivedforthefirsttimeinaself-consistentmanner.Bytheanalysisofenergydissipationinthefor-wardandreversetransformations,themieromechanicsconstitutivelawisderivedintheframeworkofHill-Rice’sinternalvariableconstitutivetheory.

  • 标签: CONSTITUTIVE element microscopic and MACROSCOPIC quantities
  • 简介:用纳米结构粉末做喂料进行喷涂,缩短了颗粒熔化时间,在有限的飞行时间内,颗粒熔化效果更好,从而制备的涂层孔隙率更小,表面更平整。用ZrO2纳米结构喂料制备了等离子喷涂层,研究了功率、粒度、氧化钇含量等工艺参数条件下涂层的微观组织、孔隙率、相组成及抗热震性能。经X衍射分析表明,原始粉末由m-ZrO2,t-ZrO2,c-ZrO2构成,单斜相的含量为11%,主要由四方相和立方相构成。

  • 标签: 二氧化锆 纳米结构 等离子喷涂层 金相组织 性能参数
  • 简介:HighactiveandstablegoldcatalystssupportedoncrystallineFe2O3andCeO2/Fe2O3werepreparedviathedeposition-precipitationmethod.ThecatalystwithaAuloadof1.0%calcinedat180°CshowedaCOconversionof100%at-8.9°C,whileAu/CeO2/Fe2O3convertedCOcompletelyat-16.1°C.Evenhavingbeencalcinedat500°C,Au/Fe2O3stillexhibitedsignificantcatalyticactivity,achievingfullconversionofCOat61.6°C.ThecatalystwithalowAuloadof0.5%couldconvertCOcompletelyatroomtemperatureandkepttheactivityunchangedforatleast150h.N2adsorption-desorptionmeasurementsshowthatthecrystallinesupportspossessedahighspecificsurfaceareaofabout200m2/g.CharacterizationsofX-raydiffractionandtransmissionelectronmicroscopyindicatethatgoldspecieswerehighlydispersedasnanoorsub-nanoparticlesonthesupports.Evenafterthecatalystwascalcinedat500°C,theAuparticlesremainedinanano-sizeofabout6―10nm.X-rayphotoelectronspectrarevealthatthesupportedAuexistedinmetallicstateAu0.ThemodificationofAu/Fe2O3byCeO2provedtobebeneficialtotheinhibitionofcrystallizationofFe2O3andthestabilizationofgoldparticlesindispersedstate,consequentlypromotingcatalyticactivity.

  • 标签: 金催化剂 CO氧化 氧化铁 Au/Fe2O3 去甲肾上腺素 X射线光电子能谱
  • 简介:氧化铝在层次地多孔的氧化锆固体酸做和硫酸化经由一个壶和bi-surfactant-assisted同时被完成了自己组装过程,把铝硫酸盐用作艾尔和SO42吗?来源。没有氧化铝没有层次地多孔的结构,做和做Al的sulfated氧化锆,准备的合成的稳固的酸与sulfated氧化锆相比为酯化作用反应显示出许多提高的酸味和再循环的催化活动。

  • 标签: 氧化铝掺杂 多孔氧化锆 一锅合成 硫酸铝 固体酸 循环利用
  • 简介:AnAu/ceria(0.44%,massfraction)catalystcontaininggoldionswaspreparedbyamodifieddepositionprecipitationmethod,andtheevolutionofgoldionsinthecatalystanditsinfluenceonthecatalysisofCOoxidationwereinvestigated.Itwasfoundthattheas-preparedcatalystcontaininggoldionswithhighvalencecouldfullyoxidizeCOat–10°CinitiallybutwasdeactivatedgraduallyatlowtemperaturesduringthereactionwithCOortreatmentbyunpurifiedair.ThedeactivationofthecatalystduringCOoxidationortreatmentofitbyunpurifiedairwasindependentandprogressiveatlowtemperatureswhiletheactivityofthecatalystatrelativelyhightemperatureswasmaintainedwell.DuringthereactionwithCOortreatmentbyunpurifiedair,theXPSresultsindicatethatgoldspeciesevolvedfromhighvalencetolowvalenceandthediffusereflectanceUV-Visspectrashowthathighvalencegoldwasreducedtochargedgoldclusters,goldclustersgrewtosmallgoldcrystalsandsmallgoldcrystalsgrewtolargegoldparticles.Accordingly,thehighvalencegoldcorrespondedtotheactivityatlowtemperaturesandthemetallicgoldwasactiveandrelativelystableathightemperatures.Theturnoverfrequencies(TOF)ofthecatalyststreatedbydifferentmethodsat273Kdecreasedwiththeevolutionofgoldspeciesfromhighvalencetolowvalence,nomaximumofTOFwasobservedalthoughgoldparticlesinthecatalystattainedtoabout2―3nmduringthetreatment.AnAu/ceriacatalystwithagoldloadof0.87%(massfraction)maintainedagoodactivityforCOoxidationwithin18hatroomtemperature.Thecatalystswerecharacterizedviatransmittedelectronicmicroscopy(TEM),inductivelycoupledplasmaopticalemissionspectrometry(ICP-OES),X-raydiffraction(XRD)andBETspecificsurfaceareaandUV-VisDRSaswell.

  • 标签:
  • 简介:<正>(a1/2)2和(a2)1/2兄妹俩,一来到花果山就受到众猴儿的青睐,争相和他俩交朋友,哪知有的小猴对他俩不礼貌,有时还受到了委屈,于是他俩就到猴王那里去告状,兄妹俩来到猴王面前,深深行了个鞠躬礼说:“报告猴王,小猴儿常把我俩张冠李戴,用我俩来解题时,

  • 标签: 算术平方根 非负数 花果山 二次根式 彻底认识 彻底了解
  • 简介:poly包括的合成聚合物电解质(用户终端设备)(vinilydenefluoride-hexafluoro丙烯),PVDF-co-HFP和锌triflate,Zn(CF3有改变ZrO2nanofillers的集中的3)2被与N扔技术的答案因此准备,N-dimethylformamide(DMF)作为普通溶剂。有特别作文的聚合物电解质标本75wt%PVDF-co-HFP:7wt%ZrO2显示出的25wt%ZnTf+4.6的最高的传导性??????????????€潰祬???????畃????猯灵??

  • 标签: 复合聚合物电解质 锌电池 电解质体系 PVDF N-二甲基甲酰胺 X射线衍射分析
  • 简介:Erbium,Ytterbium-codopedZrO2nanoparticles(ZrO2∶Er3+,Yb3+)werepreparedbythesol-emulsion-geltechnique.Thepurposeofthepresentstudyistheapplicationofupconversionphosphorinthebiologicallabel.Inordertomakeoutthemechanismofupconversionunder980nmexcitationthe488nmpumpwasused.Theinfluenceoftemperatureonthecrystallitephasewasstudied.TheresultsconfirmtheupconvertedmechanisminZrO2∶Er3+,Yb3+nanocrystalsisduetoanenergytransferupconversion(ETU).

  • 标签: 二氧化锆 能量上转换作用 作用机理 铒离子 镱离子 掺杂
  • 简介:Twonewdicyanamidecoordinationpolymers,{Mn(dmpz)[N(CN)2]2}2(1)and{Cu(dmpz)[N(CN)2]2}2(2)(dmpz=3,5-dimethylpyrazole),weresynthesizedandcharacterizedbysinglecrystalX-raydiffractionanalysisandIRspectroscopy.In1and2themetalionshavetwodifferentcoordinationmodes,whereoneiscoordinatedtofourdicyanamideanionsandtwomonodentatedmpzmoleculestoformaslightlydistortedoctahedralgeometry,whiletheotheradoptsoctahedralgeometry,surroundedbyfournitrileNatomsandtwoamideNatomsofthedicyanamideanions.Bothcomplexescontaintwoalternatingchainsthatareparalleltoeachother.

  • 标签: 氰氨基化合物 聚合体 晶体结构 3 5-二甲基吡唑
  • 简介:Hypersubstitutions是印射操作符号到相应arities的术语的地图砰。他们作为使ahyperidentity和归纳的概念精确到M-hyperidentities的一个方法被介绍。每身份作为亢奋的身份在满足的一个变化被称为固体。如果每身份是为子集Mof的M-hyperidentity所有亢奋的替换的集合,变化被称为M固体。在亢奋的替换的单音的标志和一种给定的类型的代数学的所有变化的格子的潜水艇格子之间有一个Galois连接。因此,知道怎么有趣、有用半组或在到M固体变化的相应格子的性质的这个Galois连接下面的亢奋的替换转移的单音的标志性质ofmonoids。在这篇论文,我们学习类型(2,2)的eachhypersubsfitution的顺序,即,周期的subsemigroup的顺序由类型的所有亢奋的替换的单音的标志的thathypersubstitution产生了(22)。主要结果是顺序是1,2,3,4或无限。

  • 标签: 超代换 半群 (2 2)类
  • 简介:ThesplittingofpotentialenergylevelsforgroundstateX2ΠgofOx2(x=+1,1)underspin–orbitcoupling(SOC)hasbeencalculatedbyusingthespin–orbit(SO)multi-configurationquasi-degenerateperturbationtheory(SO-MCQDPT).TheirMurrell–Sorbie(M–S)potentialfunctionsaregained,andthenthespectroscopicconstantsforelectronicstates2Π1/2and2Π3/2arederivedfromtheM–Sfunction.TheverticalexcitationenergiesforOx2(x=+1,1)areν[O+12(2Π3/2→X2Π1/2)]=195.652cm1,andν[O12(2Π1/2→X2Π3/2)]=182.568cm1,respectively.Allthespectroscopicdataforelectronicstates2Π1/2and2Π3/2aregivenforthefirsttime.

  • 标签: 分子结构 势能函数 自旋轨道耦合 电子态