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499 个结果
  • 简介:TheDCcharacteristicsofSiGeHBTirradiatedatdifferentelectrondosehavebeenstudiedinacomparisonwiththoseofSiBJT.Generally,IbandIb-Ib0increase,Ic,Ic-Ic0andits+/-transitionVbeaswellasDCcurrentgainβdecreaseswithincreasingdose;increaseofIb-Ib0withincreasingdoseforSiBJTismuchlargerthanthatforSiGeHBT;βincreaseswithVbeorIb,butdecreasesatIb<0.25mAwithIb,andcongregatesathigherdose;andadamagefactord(β)ismuchlessatthesamedoseforSiGeHBTthanforSiBJT.SiGeHBThasmuchbetteranti-radiationperformancethanSiBJT.SomeanomalousphenomenaforincreaseofIc,Ic-Ic0,Ib-Ib0andβatlowdosehavebeenfound.Someelectrontrapshavebeenmeasured.Themechanismofchangesofcharacteristicsisdiscussed.

  • 标签: 微波器件 砷化镓 硅-锗 HBT 直流电 半导体器件
  • 简介:MicrostructureandtextureofTi-Nb-Sibasedalloys,preparedbywaterquenchingfromβ-phasefield,coldrollingandrecrystallizationheattreatmentfollowedbywaterquenching,wereinvestigatedintermsofopticalmicrostructureandanalysisofX-raypolefigureresult.Inas-quenchedsample,relativelyrandomdistributionofpolefigurewasdetectedwithoutshowingaspecifictexturecomponent.Inas-coldrolledsample,however,itisfoundwell-developedseveraltexturecomponentsconsistingofrotatedcube,α-fiberandγ-fibertexturecomponentswhicharefrequentlyobservedinbcc-structuredmetalsandalloyswerefound.Therefore,texturecomponentsdevelopedinthepresentalloysarecloselyrelatedtothedeformationofβ-phaseeventhoughsmallamountofα″phaseco-existinthemicrostructure.Inrecrystallizedsample,α-fibertexturecomponentisweaklydetectedwhiletheothertexturecomponents,rotatedcubeandγ-fibercomponents,appearstoberelativelyunchanged.Noadditionaltexturecomponentsweredetectedbesidesthosetexturecomponentsobservedinthecoldrolledsamples.

  • 标签: Ti-Nb-Si BASED ALLOYS MICROSTRUCTURE TEXTURE
  • 简介:磁性的元素Fe,公司和Ni的线性热扩大(CLE)的系数用与MATLAB计算相结合的理论模型从试验性的信息被估计。模型参数能精确地被决定,并且估计的数据在对试验性的结果的好同意。便于评价,热扩大的理论被使用把CLE分开成它的无磁性、磁性的部件。对CLE的无磁性的贡献的计算基于MnBi/NdFeB混血儿的修改Grc性质结合的磁铁都逐渐地减少,当混合磁铁的密度几乎线性地改善时。在293-398的一个温度范围?K,混合磁铁的coercivity温度系数从0.59逐渐地改善?%比较。建模和频率与二低角落频率认为压力消除阀门是一个秒顺序系统是合理的试验性的结果表演。PID控制,死了的乐队赔偿控制和鷸?鷸??

  • 标签: 线性热膨胀系数 磁性元件 评估 模型参数 实验数据 MATLAB
  • 简介:ThesolidsolubilityofCe、La、SmandNdinFeorNiatvarioustemperaturewasdeterminedbymeansofadiffusion-couplemethodwiththeaidofanelectronprobemicroanalyzer.Twomethods,namelyareamethodandwholerangemethod,wereproposedfordataprocessinginthepresentpaper.Theprincipleandre-latedproblemsintheexperimentaldeterminationofthesolidsolubilityofrare-earthelementsinFeorNibyuseoftheabovementionedmethodswerealsodiscussed.

  • 标签: Solid SOLUBILITY RARE earths FE NI
  • 简介:本文从观测常规产品Ni70Mn25Co5触媒合金片的表面缺陷入手,讨论了触媒片表观质量对金刚石合成效果的影响,从而也为触媒产品质量标准的制定提供了某些参考依据。

  • 标签: Ni70Mn25Co5触媒片 表面缺陷 触媒合金 人造金刚石
  • 简介:Poroussiliconpillararray(PSPA)sampleswhichareidealsubstantialmaterialswithdominantelectronicandluminescencepropertieswerepreparedbysurfaceetchingmethod.ZnOnanorodswithorwithoutMndopinggrownuniformlyandalignedontoPSPAregardlessoflatticematchingshowvariousphotoluminescence(PL)properties.ThedopedMnionsinZnOnanorodsweredirectlyobservedbyX-rayphotoelectronspectroscopy(XPS),andZnOstructuresweredetectedbyX-raydiffraction(XRD).Asthedopingconcentrationincreases,XRDpeaksofZnOnanorodsshifttolowangle.TheinfluencesofdopingMnionsonluminescencepropertiesofZnOnanorodswereinvestigated.Exceptfortheultraviolet(UV)PLband,thebroadPLbandisobservedatvisibleregion.Thebandcouldbedividedintothreeseparatebands(orange,greenandred)byLorentziandeconvolution.TheintensityoforangePLbandfirstlyincreasesthendecreases,andthengetsthemaximumatthedopingMn-to-Znmolarratioof2.0:100.0whichisthemosteffectivedopingconcentration.ThegreenPLbandisattributedtozincvacancyofZnO,theorangePLbandtoMnionsrecombinationofitself,andtheredPLbandtooxygenvacancyofZnO,respectively.AstheMn-dopedZnOnanorodscouldemityellowgreenluminescenceexcitedbyUVradiation,anddopedMnionscouldimprovethecolorrenderingindexoftheluminescence,thenanorodscouldbeusedaspromisingwhite-lightemittersinthefuture.

  • 标签: MN掺杂 ZnO 显色指数 纳米棒 X射线光电子能谱 紫外光激发
  • 简介:Al-5Ti-0.5C-8Sr(集体部分,%)主人合金用一个melt反应方法被准备。微观结构和主人合金的合成过程被光显微镜学,X光检查衍射,扫描电子显微镜学和X光检查调查精力散的光谱。结果证明主人合金由组成一(艾尔),TiAl3,TiC,Al4Sr和Al-Ti-Sr分阶段执行。主人合金的合成机制如下:TiAl3通过在K2TiF6和艾尔之间的反应被形成在基础材料的部分融化层融化在850个C粒子与同类地分布式的加强在超声的行动和一张契约下面被变成液体filler在团结以后被获得。体积部分原文如此,在契约的粒子能被改变以铜锌金焊接的温度改变。最大值原文如此,契约材料的粒子体积部分在brazi到达了37%?

  • 标签: 中间合金 合成过程 微观结构 机制 TIAL3 X射线衍射仪
  • 简介:Thehotdeformationbehaviourof7075aluminiumalloyreinforcedwith10%ofSiCparticleswasstudiedbyemployingboth'processingmaps'andmicrostructuralobservations.Thecompositewascharacterizedbyemployingopticalmicroscopetoevaluatethemicrostructuraltransformationsandinstabilityphenomena.Thematerialinvestigatedwasdeformedbycompressioninthetemperatureandstrainraterangesof300-500℃and0.001-1.0s-1,respectively.Thedeformationefficiencywascalculatedbystrainratesensitivity(m)valuesobtainedbyhotcompressiontests.Thepowerdissipationefficiencyandinstabilityparameterswereevaluatedandprocessingmapswereconstructedforstrainof0.5.Theoptimumdomainsandinstabilityzonewereobtainedforthecomposites.Theoptimumprocessingconditionsareobtainedinthestrainraterangeof0.1-0.9s-1andtemperaturerangeof390-440℃withtheefficiencyof30%.

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  • 简介:ThemicrostructuresandVickershardnessatroomtemperatureofarc-meltingprocessedintermetallicsofMo5Si3-MoSi2hypoeutecticalloyandhypereutecticalloyannealedat1200℃fordifferenttimewereinvestigated.LamellarstructureconsistedofMo5Si3(D8m)phaseandMoSi2(C11b)phasewasobservedinallthealloys.ForMo5Si3-MoSi2hypoeutecticalloy,thelamellarstructurewasfoundonlyafterannealinganddevelopedwellwithfinespacingontheorderofhundrednanometersafterannealingat1200℃for48h.Butwhentheannealingtimewasupto96h,thewell-developedlamellarstructurewasdestroyed.ForMo5Si3-MoSi2hypereutecticalloy,thelamellarstructurewasfoundbothbeforeandafterannealing.Howeverthevolumefractionandspacingofthelamellarstructuredidnotchangesignificantlybeforeandafterannealing.Theeffectsoftheformation,developmentanddestructionoflamellarstructureonVickershardnessofalloyswerealsoinvestigated.WhenMo5Si3-MoSi2hypoeutecticalloyannealedat1200℃for48h,theVickershardnesswasimprovedabout19%comparedwiththatwithoutannealingandformationoflamellarstructure.ThehighestVickershardnessofMo5Si3-MoSi2hypereutecticwasincreasingabout18%whenannealingat1200℃for48h.

  • 标签: 室温 钼-硅系统 层状结构 显微结构 维氏硬度 退火
  • 简介:这份报纸的主要注意被奉献给在多晶的Fe82Ga18样品。合金用钮扣弧融化被融化并且在water-cooled铜模子团结了。光显微镜(OM)结果在团结微观结构证实大圆柱的谷物的发展。阶段宪法和样品的磁性的领域结构被X光检查衍射(XRD)和磁性的力量显微镜学(MFM)学习。结果为由定期排列的磁性的域组成的样品与A2结构显示出一个单相的稳固的解决方案。尽管一些像迷宫的子域在很少区域被发现,排列得好的像条纹的领域是在样品的占优势的模式。它在团结期间在一个比较喜欢的结晶的方向之上表明谷物形态学和磁性的领域结构的高依赖。

  • 标签: GALFENOL 团结质地 谷物形态学 磁性的领域结构
  • 简介:ThehydrogenstoragepropertiesofTi1.2Fe+xCa(x=1%,3%and5%inmassfraction)alloyswasinvestigated.ResultsshowthatthemodifiedalloyscanbeactivatedwithoutanythermaltreatmentatroomtemperatureduetotheadditionofCaandexcessTiinthealloys.HydrogenstoragepropertiesofthesemodifiedalloysvarywithCaamountandreactiontemperature.Inaddition,theinfluencemechanismoftheadditionofCaandexcessiveTiontheactivationbehaviorandhydrogenstoragecapacityofthealloyswasdiscussed.

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  • 简介:TheeffectsofheattreatmentsonthephasetransformationbehaviorofTi49Ni49.5Fe1V0.5andTi48Ni48.5Fe1V2.5alloyswereinvestigated.TheresultsindicatethatthealloyssubjectedtodifferentheattreatmentshaveB2structureatroomtemperature.AllthespecimensexhibitatwostageB2→R→B190martensitictransformationoncooling,butaB190→B2one-stagereversemartensitictransformationonheatingexceptagedA1alloy,whichundergoesanabnormaltwo-stagetransformationuponheating.ThephasetransformationtemperaturesareaffectedbyheattreatmentsandVcontent,whichcanbeattributedtothevariationofthesecond-phaseparticlescontentinthematrix.

  • 标签: 相变行为 热处理 合金 马氏体相变 B2结构 相变温度
  • 简介:采用纯Al片表面浸Zn后再电镀厚Cu层的方法制备Cu/Al层状复合材料。在473~673K温度范围内对该复合材料进行退火,研究退火过程中Cu/Al界面扩散与反应、界面金属间化合物(IMCs)层的长大动力学以及Cu/Al层状复合材料电阻率。结果表明,经过473K、360h的退火处理,未观察到Cu.AlIMCs层,显示Zn中间层能有效抑制Cu/Al界面扩散。可是,当复合材料经573K及以上温度退火时,Zn层中的Zn原子主要向Cu中扩散,从Al侧到Cu侧形成CuAl2/CuAl/Cu9Al4三层结构的反应产物。IMC层遵循扩散控制的生长动力学,Cu/Al复合材料的电阻率随退火温度及时间的增加而增大。

  • 标签: Cu.Al金属间化合物 层状复合材料 电镀 界面反应 生长动力学 电阻率
  • 简介:为了研究退火温度对镁合金和铝合金结合层的影响,提高扩散层的性能,采用真空扩散结合的方法焊接镁合金(AZ31B)和铝合金(6061),然后依据热处理理论在电炉中进行退火处理。应用扫描电子显微镜对焊接层的组织进行观察,利用X射线衍射技术测量残余应力,借助EPMA检测元素分布。此外,还分别测量材料的抗拉强度和硬度。结果显示,扩散层随着热处理温度升高而变宽。相比之下,在250℃退火处理后的试样残余应力值最低,抗拉强度最大。结合实验结果,250℃是镁合金和铝合金扩散结合件的最适退火温度。

  • 标签: 退火温度 扩散接合 扩散层 残余应力 拉伸强度
  • 简介:本文探讨了合金元素和退火温度对Cu-0.1Ag-xP-yMg和Cu-xSn-yTe合金(所有成分均为质量分数/%)的导热率和软化行为的影响.尽管Cu-0.1Ag-xP-yMg合金中P和Mg的含量较高,但该合金的导电率和软化温度仍然高于Cu-0.1Ag-0.031P合金.Cu-0.032Sn-0.023Te合金的导电率和软化温度与Cu-0.040Sn合金处在同一水平.Cu-0.032Sn-0.023Te合金的导电率和软化温度与目前用于连铸型材料的Cu-0.1Ag-0.013P合金相当.

  • 标签: 元素铜基 合金元素 合金导热
  • 简介:通过第一性原理计算方法研究了Mg-Al-Ca-Sn合金中主要强化相Mg17Al12,Al2Ca,Mg2Sn和Mg2Ca的结构稳定性、电子结构、弹性常数和热力学性质。计算所得晶格常数与实验值及文献值吻合。合金形成热和结合能计算结果表明,Al2Ca具有最强的合金形成能力及结构稳定性。通过对这些化合物的态密度、Mulliken电子占据数、金属性和差分电荷密度计算分析了其结构稳定性的机制。通过计算Mg17Al12,Al2Ca,Mg2Sn和Mg2Ca的弹性常数,推导出了各相的体模量、剪切模量、杨氏模量和泊松比。热力学性质计算结果表明,Al2Ca和Mg2Sn的Gibbs自由能低于Mg17Al12,即Al2Ca,Mg2Sn的晶体结构稳定性优于Mg17Al12相。因此,通过添加Ca和Sn元素可以提高Mg-Al合金的热力学稳定性。更多还原

  • 标签: Mg-Al系合金 第一性原理计算 电子结构 弹性性质 热力学性质
  • 简介:Thecorrosionbehaviorandanti-corrosionmechanismoftheZn-Ni-Al2O3compositecoatingwereinvestigatedbySEM,EDSandXPS.TheresultsindicatethatthecorrosiontypeoftheZn-Ni-Al2O3coatingsinneutral5wt.%NaClsolutionisuniformcorrosion.ThepresenceofcompactanduniformlydispersednanoaluminaparticlessubstantiallyinhibitsthecorrosionofZn-Ni-Al2O3compositecoatings.Intheinitialcorrosionstage,thecorrosiveproductsofZn-NimatrixformacompactZnCl2·4Zn(OH)2layer.Withthedevelopmentofcorrosion,somenanoaluminaparticlesareembeddedandformaNienrichmentlayer.InNienrichmentlayer,NipresentsasNiandNiO.

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