学科分类
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394 个结果
  • 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。

  • 标签: 纳米FE3O4 磁性纳米粒子 合成系统 单分散 FE3O4纳米粒子 可控
  • 简介:用机械合金化方法制备了(FeAl3)75Zr25和(FeAl3)50Zr50非晶态合金,用X射线衍射仪和热分析仪对制备的非晶态合金的结构特性及热稳定性进行了研究,用振动样品磁强计对(FeAl3)75Zr25和(FeAl3)50Zr50混合粉末在机械球磨过程中的磁性变化进行了研究,并对其晶化产物及其晶化后合金的磁性进行了分析。结果表明:(FeAl3)75Zr25的晶化产物为Fe3Zr和Al1.65Fe0.33Zr;(FeAl3)50Zr50非晶态合金的晶化产物为FeZr2和AlZr2。(FeAl3)75Z

  • 标签: 机械合金化 非晶合金 磁性能
  • 简介:利用里兹(Ritz)变分法求解氢分子离子H+2的键长和基态能量E,并通过计算机来完成理论公式的推导与数值模拟

  • 标签: 氢分子离子H+2 键长 基态能量
  • 简介:估计在像钻石的碳(DLC)的sp(3)的内容拍摄的一个新实验模型被介绍,基于为不同的碳的488nm或514nmvisible光激动的传统的拉曼系列。G山峰的带宽与thesp(3)有关是部分,这被发现。G山峰的更宽的带宽在DLC电影显示出更高的sp(3)部分。

  • 标签: 碳元素 薄膜 模型 钻石
  • 简介:Atemperature-inducedspinreorientationtransitionbetweenГ4(Gx,Ay,Fz)andГ2(Fx,Cy,Gz)hasbeenstudiedinthefamilyofEr1–xYxFeO3(x=0,0.25,0.5,0.75,1)singlecrystals.BydopingnonmagneticY3+,wetunedthespinreorientationtemperaturetolowtemperaturewithincreasingx.Moreover,thetypicalcompensationpointandspinfliptransitionofErFeO3alsodecreaseswithdoping,anddisappearsabovex=0.75.WealsoreporttheRietveldrefinementsandRamanspectroscopyofEr1–xYxFeO3,wheresomeRamanpeaksareshiftedtolowfrequencywithincreasingdoping.Ourresultsshedlightontheunderstandingoftheinteractionbetweentwomagneticsub-latticesofrareearth(R3+)andiron(Fe3+)ions,andwillalsocontributetothematerialsdesignandpotentialapplications.

  • 标签: Er1–xYxFeO3 single CRYSTAL GROWTH MAGNETIC MEASUREMENTS
  • 简介:Thispaperpresentsanexperimentalstudyofthethree-dimensionalturbulentflowfieldsinalowspeedannularcascadeofhighturningangleturbineblades.Detailedmeasurementswereperformedonthebladesurfacesandmid-streamsurfaceinthepassageandatthreeaxialplanesdownstreamofthecascadebyusingwallstaticpressuretaps,afive-holeprobeandahot-wireanemometer,Thetestdataincludestaticpressuredistributiononbladesurfaces,totalpressurelosscofeeicient,meanflowvelocitycomponents.radialflowangle,turbulenceintensityandReynoldsshearstress.Analysesofthethree-dimensionalcascadeflowcharacteristicsweremadeonthenosetlocationofhighlossvortices.thevariationofpressuregradientinsidethecascadepassageandthepropertiesofendwallboundarylayerstotalpressurelossdistributions,secondaryvortexturbulentdissipationandwakedecaydowntreamofthecascade.Theseexperimentalresultsarevaluableforrevealingthedetailsofthecomplexvortexflowstructureinmodernhighlyloadedaxialturbomachinesandvalidatingthethree-dimensionalflownumericalcomputationcodes.

  • 标签: 透平机叶片 级联损耗 紊流
  • 简介:谈论物理教学为何与何为,实验探究教学当是主要方面.“为何”就是怎么看,就是要在思想上提高认识;“何为”就是怎么做,就是要在实践上提高能力.因此,提升实验探究教学水平,要在“深切理解实验探究价值,提高自身实验探究水平,谋求有效的教学策略方法”几方面做足文章.1.深切理解实验探究的价值

  • 标签: 实验探究 教学水平 物理教学 探究教学 教学策略 价值
  • 简介:Basedontheextendedmappingdeformationmethodandsymboliccomputation,manyexacttravellingwavesolutionsarefoundforthe(3+1)-dimensionalJMequationandthe(3+1)-dimensionalKPequation.Theobtainedsolutionsincludesolitarysolution,periodicwavesolution,rationaltravellingwavesolution,andJacobianandWeierstrassfunctionsolution,etc.

  • 标签: 非线性偏微分方程 JM函数 行进波 精确解
  • 简介:Inordertodeepentheunderstandingoftherelationshipbetweenfundamentalproperties(including:microstructureandcomposition)andphotocatalyticperformance,fourbismuthatecompounds,including:LiBiO3,NaBiO3,KBiO3,andAgBiO3,areregardedasresearchexamplesinthepresentwork,becausetheyhaveparticularcrystalstructuresandsimilarcompositions.Usingdensityfunctionaltheorycalculations,theirstructural,electronic,andopticalpropertiesareinvestigatedandcomparedsystematically.Firstofall,thecalculatedresultsofcrystalstructuresandopticalpropertiesareinagreementwithavailablepublishedexperimentaldata.Basedonthecalculatedresults,itisfoundthatthetunneledorlayeredmicro-structuralpropertiesleadtothestrongerinteractionbetweenbismuthandoxygen,andtheweakerinteractionbetweenalkaline-earthmetaland[BiO6]octahedron,resultinginthefeatureofmulti-bandgapsinthecasesofLiBiO3,NaBiO3,andKBiO3.ThisconclusionissupportedbythecaseofAgBiO3,inwhichthefeatureofmulti-bandgapsdisappears,duetothestrongerinteractionbetweenthenoblemetaland[BiO6]octahedron.Thesepropertieshavesignificantadvantagesinthephotocatalyticperformance:absorbinglowenergyphotons,rapidlytransferringenergycarriers.Furthermore,thefeaturesofelectronicstructuresofbismuthatecompoundsarewellreflectedbytheabsorptionspectra,whichcouldbeconfirmedbyexperimentalmeasurementsinpractice.Combinedwiththecalculatedresults,itcouldbeconsideredthatthecrystalstructuresandcompositionsofthephotocatalystdeterminetheelectronicstructuresandopticalproperties,andsubsequentlydeterminethecorrespondingphotocatalyticperformance.Thus,anovelBi-basedphotocatalystdrivenbyvisible-lightcouldbedesignedbyutilizingspecificcompositionstoformfavorableelectronicstructuresorspecificmicro-structurestoformabeneficialchannelforenergycarriers.

  • 标签: 电子结构 光催化剂 光催化性能 弱相互作用 计算结果 NA