学科分类
/ 2
37 个结果
  • 简介:根据麦克斯韦的理论,在GeSi/Si超点阵nanocrystalline层的光传播特征被分析了并且计算。计算结果证明当全部的厚度L是340nm时,单个模式lightwave能仅仅在周期的数字M15.5被播送。在传播的方向,当传播距离比500m大时,另外,lightwave紧张极大地被减少。基于GeSi/Si超点阵nanocrystalline光电探测器的上述参数,设计和制造被执行。

  • 标签: GESI/SI 超晶格 纳米晶体 光电探测器 光学性质
  • 简介:AnewtechniqueofthesynthesisofNanocrystallineDiamond(NCD)Filmsbyheliconwaveplasma(HWP)chemicalvapordepositionatroomtemperaturewasreported.ThegrowthmorphologyandtheroughnessofNCDsampleswascharacterizedusingfiledemissionscanningelectronmicroscopy(SEM-SU8010)andatomforcemicroscopy(AFM),respectively.Theresultsshowthegrowthrateofthefilmwasveryfast,about833nm/min.TypicalG,Dbands

  • 标签: 英语 阅读 理解 纳米材料与技术
  • 简介:NanocrystallineNi粉末成功地被制作由机械地在有1个wt.%Y_2O_3粒子的低温实验法的温度(cryomilling)的milling。试验性的结果证明了Ni谷物尺寸面对Y_2O_3粒子在cryomilling的2h以后被归结为25nm。cryomilledNi/Y_2O_3粉末能维持他们的nanocrystalline结构直到900℃,否则融化中的62%个Ni指。有约100nm的athermally稳定的谷物尺寸的体积nanocrystallineNi/Y_2O_3材料被cryomilling生产,冷均衡说的紧迫,由热均衡说的压列在后面。体积nanocrystallineNi/lwt.%Y_2O_3的微坚硬是315DPH,它二倍高于常规Ni的。

  • 标签: 纳米晶镍粉末 合成 特性 低温研磨 液氮
  • 简介:在二进制Sm公司系统的许多金属间化合的混合物被考察,并且内容集中于水晶结构,磁性和nanoscale效果。代表性的nanocrystallineSm公司混合物在细节,为他们的格子结构的图和原子地点被介绍,占有被提供。而且,nanocrystallineSm公司混合物的磁性与常规多晶的对应物的那些相比。它证明nanocrystallineSm公司混合物展览专辑阶段稳定性和显著地提高的磁性的性能,它是矩阵的有希望的候选人分阶段执行开发永久磁铁,特别地先进高温度的磁性的材料。

  • 标签: 金属间化合物 纳米尺度 磁学性能 晶体结构 原子位置 晶格结构
  • 简介:DiffusionofAlinthinfilmnanocrystallineCu(18nm)hasbeeninvestigatedbymeansofsecondionmassspectroscopy(SIMS).Intheexperimentaltemperaturerangesfrom421to773K,thereseem-inglyexiststwodiffusionmechanisms.TheimpurityelementsOandCaresupposedtoaccumulatetothegrainboundariesandinhibitthefastgrainboundarydiffusion.

  • 标签: TRACER DIFFUSION NANOCRYSTALLINE SPECTROSCOPY
  • 简介:Extendedx-ray-absorptionfine-structuremeasurements(EXAFS)wereperformedonnanocrystalline(nc)elementalSesampleswithgrainsizesrangingfrom13to60nm.Accompaniedwiththepreviousstudy,weconcludedthat,withtherefinementinnc.Se.theintrachainstructure(thebondlength,thecoordinationnumber)isunchangedwhiletheinterchainspacingisenlarged.ThegrainboundaryinthencSeisfoundtobeinalow-energyconfigurationthatisdifferentfromthedisorderedgaslikegrainboundarystructure.

  • 标签: 纳米结晶 结构特征 晶粒尺寸
  • 简介:Micro-/nanocrystallinediamondfilmsdepositedinAr/H2/CE4microwaveplasmashavebeenstudied,withargonflowratesintherangeof70-100seem.Theeffectsofargonadditiononmorphology,surfaceroughness,qualityandstructurewereinvestigatedbyscanningelectronmicroscopy,surfaceprofiler,RamanspectrometerandX-raydiffraction(XRD).Itisdemonstratedthatwhentheargonflowrateis70sccmor75sccm,well-facetedpolycrystallinediamondfilmscanbegrownatalowsubstratetemperaturelessthan610℃.Withtheincreaseintheargonflowrate,thesmoothcrystallographicplanesdisappeargradually.Instead,roughcrystallographicplanesmadeupofsmallaggregatesbegintotakeshape,resultingfromtheincreaseinthesecondarynucleationrate.Nanocrystallinediamondfilmswereobtainedataflowrateof100sccm,andalloftheprepareddiamondfilmsweresmooth,withasurfaceroughness(Ra)lessthan20nm.Ramananalysesrevealthattheamountofamorphouscarbonincreasessignificantlywiththeincreaseinargonflow.TheresultsofXRDshowthatcrystallinesizeandpreferentialorientationofdiamondfilmsdependontheargoncontentintheplasmas.

  • 标签: 纳米金刚石薄膜 氩含量 结构 形态 微波等离子体 扫描电子显微镜
  • 简介:敏化染料的太阳能电池(DSC)在于有nanoparticulated半导体,sensitizers,电解质和相反的电极(CE)的几differentmaterials:photoanodes的联合。每材料为CE的主要功能是把电子转移到氧化还原作用电解质和regenerate碘化物离子的太阳能intoelectricity.The的变换执行特定的任务。GE的工作主要集中于运动表演的研究和传统的CE的稳定性改进DSC的全面效率,寻求新奇设计概念或新材料。在这评论,发展和研究不同CE材料和他们的电气化学的表演进行,并且这些问题被讨论。

  • 标签: 计数器电极 燃料 敏化作用 聚合物
  • 简介:ZrO2-SnO2compositenanoparticleswerepreparedbyheatingthehydrateprecursorssynthesizedbythechemicalco-precipitationreactionofZrOCl2andSnCl4.Theprecursorswereexaminedbydifferentialthermalanalysis(DTA)andthermogravimetricanalysis(TGA).ThecompositepowderwascharacterizedusingX-raydiffraction(XRD),transmissionelectronmicroscopy(TEM)anddesorptionisotherm(Barrett-Joyner-Halendamethod).Theaveragecrystalsizeofthenanoparticlerangesfrom15to30nmforthesamplecontaining5%-25%ZrO2(massfraction).MostoftheporesintheZrO2-SnO2nanoparficlesareabout10-20nmindiameter.Thecompositepowderispromisingforchemicalsensors.

  • 标签: 化学合成 纳米晶体 无机材料 氧化锆 氧化锡 复合粉末
  • 简介:Themicrostructureofstress-inducedmartensite(SIM)inthenanocrystallineNiTialloywasinvestigatedbymeansoftransmissionelectronmicroscopy(TEM).Theresultshowsthatthemulti-variantstructureofthemartensiteissuppressedandonlysingle-variantmartensitictwinsformaftertensiledeformationwhenthegrainsizeissmallerthan80nm.Thenormaldirectionsofthe(001)B190twinplanesareallwithintherangeof45°fromtheaxialdirectionofthewire.Theanglebetweentwincrystals(1'11)Mand(111)ToftheSIMisalsofoundtobesmallerthanthatofthermallyinducedmartensiteinnanocrystallineNiTi.

  • 标签: 应力诱发马氏体 镍钛形状记忆合金 纳米晶体 透射电子显微镜 组织 NITI合金
  • 简介:Inthiswork,boththethermalexpansionandelectricalconductivityofnanocrystallineLa2Mo2O9werestudied.ThenanocrystallinepowderofLa2Mo2O9wasobtainedbysol-gelmethod,andwiththehelpofSHP(superhighpressure)upto4.5×104atmat700℃forashorttime,andthenanocrystallinepowderwasdensifiedwithoutobviousparticlesizegrowth.TheelectricalconductivityofnanocrystallineLa2Mo2O9wasoneorderofmagnitudelowerthanthatofthemicrocrystallinesampleatthesametemperature.Owingtothephasetransition,themicrocrystallineLa2Mo2O9hasanabruptincreaseofthermalexpansionwithapeakvalueof48×10-6K-1at556℃.Forthenanocrystallinematerial,thepeakvalueincreasesto112×10-6K-1at520℃.Ontheotherhand,above600℃thesignificantgrowthofparticlesizeofthenanocrystallineLa2Mo2O9wasobserved,accompanyingbyatremendousincreaseofthermalexpansionwithapeakvalueofthirdhigherthanthatofLa2Mo2O9.

  • 标签: NANOCRYSTALLINE electrical CONDUCTIVITY LANTHANUM MOLYBDATE superhigh
  • 简介:有关于30-50nm的谷物尺寸的nanocrystallineMg2Si(n-Mg2Si)的Densification行为被hot-pressing在显示的400°C.The结果调查n-Mg2Si的那个thedensification过程展出了三线性segments:p<0.3GPa,0.3GPa1.2GPa由Heckel决定了公式,在哪个之中在高压力范围p>1.2GPa的第三个快增加片断很少在常规纹理粗糙的polycrystallinematerials.Nevertheless被报导了,在调查的整个压力范围(0.125-1.500GPa),n-Mg2Si的densificationbehavior能是Kawakita公式p/C=(1/a)描述的井有在对协议的起始的孔的好同意的constanta=0.452的p+1/(ab)。

  • 标签: 稠化作用 热压制技术 MG2SI 特殊材料