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68 个结果
  • 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?????????????????@

  • 标签: 纳米粒子 铕掺杂 氧化镓 水热合成 十二烷基苯磺酸钠 透射电子显微镜
  • 简介:EnthalpyofReactionsinY-Ba-Cu-OSystemShaWei沙维(Departmentof.MaterialsScienceandMetallurgy,UniversityofCambridge.U.K.)Received17...

  • 标签: THERMODYNAMIC PROPERTIES SUPERCONDUCTORS PHASE TRANSFORMATION
  • 简介:BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope(SEM),electron.probemicroanalysis(EPMA)andX-raydiffraction(XRD).theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.

  • 标签: ALUMINA active BRAZING INTERFACIAL reaction joint
  • 简介:采用固相法制备La2O3与Sb2O3掺杂的钛酸锶钡陶瓷,研究其介电性能及相变特性。通过X射线衍射法分析体系微观结构并利用扫描电镜观察其表面微观形貌。(La,Sb)共掺杂的钛酸锶钡陶瓷具有典型的钙钛矿结构,且随着Sb2O3掺杂量的增多其平均粒径显著减小。La3+离子以及Sb3+离子均占据钙钛矿晶格的A位。La2O3与Sb2O3添加量的改变显著影响钛酸锶钡基陶瓷的介电常数以及介电损耗。La2O3改性的钛酸锶钡陶瓷其四方-立方相变为二级相变,且居里温度随着La2O3掺杂量的增多向低温方向移动。(La,Sb)共掺杂的钛酸锶钡陶瓷则体现为弥散相变,随着Sb2O3含量的增大而偏离居里-外斯定律越显著。由于Sb3+离子对晶格原位离子的取代使得(La,Sb)共掺杂的钛酸锶钡陶瓷的介电常数最大值下的温度亦随着Sb2O3含量的增大而降低。

  • 标签: 钛酸锶钡 LA2O3 SB2O3 钙钛矿 陶瓷 介电性能
  • 简介:BasedonthetechniqueforpreparingLaCl3viadirectpyrolysisofrareearthchloridesolution,ajetpyrolysisreactorwasdesignedandtheintra-reactortemperatureandchemicalreactionswerenumericallysimulatedusingcomputationalfluiddynamics(CFD)technique.Theresultsshowthattheflowratevariationatthefuelinletdoesnotlargelyaffectthetemperatureinthereactor,whiletheincreaseinexternalpressureatthematerialinletrapidlydecreasestheaveragetemperature,Venturitemperature,andoutlettemperature.TheCH4andO2insidethereactorarecombustedcompletely,andwhenthematerialinletpressureis\90Pa,theLaCl3isfullypyrogenated.ThecontentsofCO2,La2O3,andHClfluctuateneartheVenturitubeandfinallystabilize.La2O3contentattheoutletisinatop-to-bottomgradient.

  • 标签: Jet-flow PYROLYSIS Chemical REACTION NUMERICAL SIM
  • 简介:Thecorrosionbehaviorandanti-corrosionmechanismoftheZn-Ni-Al2O3compositecoatingwereinvestigatedbySEM,EDSandXPS.TheresultsindicatethatthecorrosiontypeoftheZn-Ni-Al2O3coatingsinneutral5wt.%NaClsolutionisuniformcorrosion.ThepresenceofcompactanduniformlydispersednanoaluminaparticlessubstantiallyinhibitsthecorrosionofZn-Ni-Al2O3compositecoatings.Intheinitialcorrosionstage,thecorrosiveproductsofZn-NimatrixformacompactZnCl2·4Zn(OH)2layer.Withthedevelopmentofcorrosion,somenanoaluminaparticlesareembeddedandformaNienrichmentlayer.InNienrichmentlayer,NipresentsasNiandNiO.

  • 标签:
  • 简介:Fe2O3和ZnO的粉末混合物是在一家高精力的行星的球工厂的milled综合ZnFe2O4和X光检查粉末diffractometry被用来获得阶段,雏晶尺寸和Fe2O3和ZnFe2O4的microstrain的相对内容。Fe2O3的格子常数被房间精炼方法获得。macrokinetics和事的结构进化被学习,结果证明ZnFe2O4的mechanochemical合成的动力学过程适合Avrami-Erofe'ev模型并且被成核生长机制,和结构的macrokinetics理论在燃烧合成研究控制区域能被用来也描述运动过程。

  • 标签: 结构宏观动力学 合成过程 铁酸锌 机械球磨 粉末衍射仪 行星球磨机
  • 简介:ThermodynamicmodelsofcalculatingmassactionconcentrationsforstructuralunitsorioncouplesinRbCl-H2ObinaryandRbCl-RbNO3-H2Oternarystrongelectrolyteaqueoussolutionsweredevelopedbasedontheionandmoleculecoexistencetheoryat298.15K.Atransformationcoefficientisneededtocomparethecalculatedmassactionconcentrationandthereportedactivitybecausetheyareobtainedatdifferentstandardstatesandconcentrationunits.TheresultsshowthatthetransformationcoefficientsbetweenthecalculatedmassactionconcentrationsandthereportedactivitiesofthesamestructuralunitsorioncouplesinRbCl-H2ObinaryandRbCl-RbNO3-H2Oternarystrongelectrolyteaqueoussolutionschangeinaverynarrowrange.ThetransformedmassactionconcentrationsofstructuralunitsorioncouplesinRbCl-H2Obinarysystemareingoodagreementwiththereportedactivities.ThetransformedmassactionconcentrationsofRbClandRbNO3inRbCl-RbNO3-H2Oternarysolutionarealsoingoodagreementwiththereportedactivities,aRbCland3RbNOa,withdifferenttotalionicstrengthsas0.01,0.05,0.1,0.5,1.0,1.5,2.0,3.0and3.5mol/kg,respectively.AllthoseresultsmeanthedevelopedthermodynamicmodelofstrongelectrolyteaqueoussolutionscanreflectstructuralcharacteristicsofRbCl-H2ObinaryandRbCl-RbNO3-H2Oternarystrongelectrolyteaqueoussolutionsandthemassactionconcentrationalsostrictlyfollowsthemassactionlaw.

  • 标签: 电解质水溶液 计算单位 三元体系 结构单元 二元体系 浓度模型
  • 简介:多层的Nb2O5部nanoporous电影被控制阳极化过程成功地在包含4的乙烯乙二醇在Nb表面上综合?vol%HF并且2?vol%H2O2电解质。nanoporous电影被地排放扫描详细描绘电子显微镜学(FESEM),传播电子显微镜学(TEM),和X光检查衍射(XRD)。Nb2O5部nanoporous电影与~的方面墙厚度有多层的形态学5?nm,有~的一条直径的不规则的毛孔25?nm,并且一段多达7.39?m,取决于阳极化时间。为多层的Nb的机制<潜水艇class=“a-plus-plus”>2O<潜水艇class=“a-plus-plus”>5nanoporous形成也被讨论。这些nanoporous材料能在太阳能电池,煤气的传感器,催化剂,光过滤器,和电容器的地里是很有用的。

  • 标签: 纳米多孔膜 阳极化 阳极氧化工艺 NB2O5 扫描电子显微镜 透射电子显微镜
  • 简介:ThispaperintroducesabrazingprocessbetweenAl_2O_3ceramicandInvaralloy.Al_2O_3canbebrazedwithInvareffectively.TheinterfacialstructureofAl_2O_3/Invarjointcanbeexpressedas:Invar/Ag(s,s)+Cu(s,s)+Fe_2Ti(zoneⅠ)/Ag(s,s)+Cu(s,s)+Fe_2Ti+NiTi+Cu_3Ti(zoneⅡ)/Ag(s,s)+Cu(s,s)+Cu_2Ti+Al(s,s)+TiC+TiO(zoneⅢ)/Al_2O_3.Themaximumshearstrengthof139MPawasmeasuredforas-brazedAl_2O_3/Invarjointbrazedat850℃for25minor900℃for15min.

  • 标签: AL2O3陶瓷 钎焊接头 界面结构 力学性能 因瓦合金 剪切强度
  • 简介:ScanningElectronMicroscopyStudiesofYBa_2Cu_3O_(7-δ)SuperconductorsShaWei(沙维)(DepartmentofCivilEngineering,TheQueen′sUniversit...

  • 标签: SUPERCONDUCTORS Thin film Ion IMPLANTATION Scanning
  • 简介:HotcompressionbehaviorofTiC–Al2O3/AlcompositeswasstudiedusingtheGleeble-1500systematatemperaturerangeof300–550°Candatstrainraterangeof0.01–10.00s-1.TheassociatedstructuralchangeswerestudiedbyTEMobservations.Theresultsshowthatstressleveldecreaseswithdeformationtemperatureincreasingandstrainratedecreasing,whichcanberepresentedbyaZener–Hollomonparameterinanexponent-typeequationwithhotdeformationactivationenergyQof172.56kJ·mol-1.Dynamicrecoveryoccurseasilywhenstrainratesarelessthan10.00s-1.Dynamicrecrystallizationcanoccuratstrainrateof10.00s-1.

  • 标签: TiC–Al2O3/Al COMPOSITES HOT DEFORMATION Flow stres
  • 简介:采用丝印法在铝基板上制备具有低室温电阻率、适中热敏常数的负温度系数BaCo0.02ⅡCo0.04ⅢBi0.94O3/Ba0.5Bi0.5Fe0.9Sn0.1O3复合热敏厚膜。采用数字多用表、吉时利2400和阻抗分析仪对热敏厚膜的电学性能进行表征。结果表明:随着Ba0.5Bi0.5Fe0.9Sn0.1O3含量从0.05增加至0.25,厚膜的室温电阻率、热敏常数和峰值电压均有所增加且分别处于1.47-26.5Ω·cm、678-1345K和18.9-47.0V范围内,厚膜峰值电压对应的电流也有所降低且处于40-240mA范围。阻抗谱测试表明,这些热敏厚膜表现出非正常的异质电学微结构行为,由高阻态的晶粒和较低电阻态的晶界区域构成。由此可知,在BaCo0.02ⅡCo0.04ⅢBi0.94O3中添加Ba0.5Bi0.5Fe0.9Sn0.1O3改善了热敏行为但也恶化了电流特征.

  • 标签: 负温度系数热敏厚膜 BaCo0.02 ⅡCo0.04ⅢBi0.94O3 Ba0.5Bi0.5Fe0.9Sn0.1O3 电学性能
  • 简介:ExtractingB2O3fromcalcinedboronmud(CBM)wasstudied.TheeffectoffactorssuchasreactiontemperatureandNaOH-to-CBMmassratioonB2O3extractionefficiencywasinvestigated.TheresultsshowthatincreasingreactiontemperatureandNaOH-to-CBMmassratioincreasesB2O3extractionefficiency.TherearetwostagesfortheB2O3extractingprocess:0–20ministhefirststage,whichisrapid;20–50ministhesecondstage,whichisslowerthanthefirststage.Theoverallextractingprocessfollowstheshrinkingcoremodel,andthefirstandsecondstagesaredeterminedtoobeythesurfacechemicalreactionmodelandthediffusionthroughtheproductslayermodel,respectively.Theactivationenergiesofthefirstandsecondstagesarecalculatedtobe41.74and15.43kJ·mol-1,respectively.TheB2O3extractingkineticsequationsofthefirstandsecondstagesarealsoobtained.

  • 标签: BORON MUD Sodium HYDROXIDE BORON oxide
  • 简介:高质量的取向附生的YBa2Cu3O7-(YBCO)超导的电影被制作在上(OOl)用直流的劈啪作响方法的LaAlO3底层。不平常地高的电影厚度的成就(多达2.0嗯)没有microcracking,部分地被归因于毛孔的存在在这些电影与充满钇的作文相关。微观结构上的电影厚度的影响被X光检查衍射调查常规扫描(-2,-scan,杆数字)和印射的高分辨率的相互的空间。电影是没有直到2m的厚度的a-axis-oriented谷物面向的c轴。表面形态学和批评当前的密度(Jc)强烈取决于电影厚度。而且,为这些厚度依赖的原因详细被阐明。

  • 标签: 超导薄膜 微裂纹 临界电流密度 喷射法
  • 简介:ElectrocrystallizationMechanismofTungsteninMoltenKF-B_2O_3-K_2WO_4WenZhenhuanandLiGuoxun文振环,李国勋(GeneralResearchInstiiuteforNo...

  • 标签: ELECTROCRYSTALLIZATION mechanism TUNGSTEN Electrodeposition Mol-ten KF-B2O3-K2WO4
  • 简介:polyacrylonitrile(平底锅)上的electrodepositingFe-Cr2O3合成涂层的过程基于碳纤维,它的催化graphitization被学习。有或没有electrodepositedFe-Cr2O3合成涂层的碳纤维是在不同温度对待的热,结构的变化被XRD,拉曼光谱学和SEM描绘。结果显示那Fe-Cr2O3合成涂层在低温度在碳纤维的graphitization上展出重要催化效果。当Fe-Cr2O3-coated碳纤维是时,热对待在1300?慢敳?慣'R湯映扩牥映汥?獡琠敨瀠敲畣獲牯映汯潬敷?祢椠灭敲湧瑡潩?楷桴爠獥湩?潭摬湩?湡?敨瑡琭敲瑡敭瑮楴?楴吗??

  • 标签: CR2O3涂层 化学复合镀层 催化石墨化 聚丙烯腈 碳纤维 PAN
  • 简介:2003年上半年全球政治经济形势错综复杂,在世界经济尚处于低谷时,美国对伊拉克动武对经济的复苏产生了一些负面影响,紧随其后SARS疫情的爆发又给中国这个全球经济发展的亮点蒙上了阴影,基本金属的市场行惰难免受到大势的拖累,但是镍的表现异常抢眼,6月初已回升至9550美元/吨的高位,达到了近三年来的高点.2003年上半年LME镍现货平均价为8359美元/吨,比2002年同期上涨了27.8%.

  • 标签: 国内外镍 市场热点 热点分析