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41 个结果
  • 简介:Inthiswork,SMAT(surfacemechanicalattritiontreatment)wasperformedonTi6Al4V.PlasmanitridingoftheSMATedsampleswasinvestigatedincomparisonwithcoarse-grainedsamples.Thesampleswerecharacterizedusingopticmicroscope,SEM,TEMandVickersmicrohardnesstester.TheresultsshowedthatasignificantlythickercompoundlayerwithhigherhardnesswasobtainedfortheSMATedsampleswhencomparedwithun-SMATedsamplesafternitriding.CorrosionresistanceofTi6Al4VinaRinger’ssolutionwasstudiedbyelectrochemicaltechniquesincludingopencircuitpotentialmeasurement,potentiodynamicpolarizationandEIS(electrochemicalimpedancespectroscopy).Overall,ourresultsidentifiedthebeneficialimpactsoftheduplexSMAT/nitridingtreatmentoncorrosionbehaviourofTi6Al4V.Weartestswerealsoperformedonaball-on-disctribometerwherethetreatedsampleswererubbedagainsta6mmdiameteraluminaballunderanormalloadof5NusingRinger’ssolutionaslubricantmedia.ThefrictioncoefficientoftheSMATedandnitridedsampleswasreducedcomparedtotheuntreatedsamples.WearratesdemonstratedthatSMATcombinedwithnitridingimprovedwearresistanceofTi6Al4Valloy.

  • 标签: Surface mechanical attrition treatment PLASMA NITRIDING
  • 简介:<正>Someproblemsinusingv-supportvectormachine(v-SVM)forthepredictionofnonlineartimeseriesarediscussed.Theproblemsincludeselectionofvariousnetparameters,whichaffecttheperformanceofprediction,mixtureofkernels,anddecompositioncooperationlinearprogrammingv-SVMregression,whichresultinimprovementsofthealgorithm.ComputersimulationsinthepredictionofnonlineartimeseriesproducedbyMackey-GlassequationandLorenzequationprovidesomeimprovedresults.

  • 标签: v-SVM NONLINEAR time series prediction
  • 简介:在Cr12MoV模具表面进行了激光熔覆试验,探讨了工艺参数对熔覆层深度影响、显微硬度和合金元素分布、表面耐磨性能的变化的趋势,为激光重熔技术的应用提供依据。

  • 标签: 模具钢 工艺参数 表面改性 光熔覆 组织结构
  • 简介:介绍了阻变存储器及其I-V特性的测试分析方法。通过测量三明治结构的阻变存储器的I-V特性,采用多种拟合方法,与导电机制原理对比,可以判断器件的导电机制,便于深入分析阻变机理。

  • 标签: 电致阻变 I-V特性 导电机制
  • 简介:随着材料科学技术的不断进步,新型高强度、高韧性的难加工材料不断出现。图1所示零件,材料为超高强高韧,孔深与孔径之比约为10:1,内孔为小锥度锥面,孔末端为异型回转曲面,外圆柱面和内孔有较高的同轴度要求。零件深孔加工中刀具细而长,刚性差,工件尺寸精度、表面质量不易保证。

  • 标签: 高强高韧钢 制造技术 异型 深盲孔 材料科学技术 难加工材料
  • 简介:IncorporationofstrontiumintoV-Moalumina-supportedcatalystenhanceditsperformance(increasedconversionandselectivity,decreasedreducibilityandimprovedstability)inpropaneoxydehydrogenationtopropylene.12.5%SrloadingwasshowntobetheoptimumcontenttotheV-Mocatalyst.Theresultsweresupportedbyvariouscharacterizationtechniques,namely,BET,XRD,SEM,FTIRandTPD.

  • 标签: oxydehydrogenation STRONTIUM vanadium-molybdenum oxides CATALYSTS PROPANE
  • 简介:Theelectronicstructures,dielectricfunctions,complexrefractiveindicesandabsorptionspectraforaperfectPbW04(PWO)crystalandthePWOcrystalscontainingleadvacancyV^2-pbhavebeencalculatedusingafull-potential(linearized)augmentedplane-wave(LAPW)+localorbitals(LO)methodwiththelatticestructureoptimized.Thepeaksoftheabsorptionspectracorrespondingtotheelectronictransitionshavebeenstudied.

  • 标签: 电子结构 光学性质 钨酸铅晶体 V^2-pb 线性平面波法
  • 简介:因为graphene和phosphorene,二维(2D)组IV和组V元素的分层的材料引起大兴趣。然而,组IVV单层没收到到期的注意。在这个工作,啜单层的三种类型计算地被设计探索他们的电子结构和光性质。计算证实这些单层的稳定性,它都是有在范围的bandgaps的indirect-bandgap半导体1.382.21eV。bandgaps在pH=跨骑水的氧化还原作用潜力0,用作watersplitting光催化剂显示单层的潜力。计算光性质证明啜2D材料的某些单层是可见的光的吸收器并且将用作optoelectronic设备的好候选人。

  • 标签: 电子结构 光催化剂 单层 2D 可见光 混合物
  • 简介:为了研究弹丸头部形状以及初速对薄靶穿甲机理的影响,本文针对平头和球头弹丸对薄靶的穿甲问题,采用数值模拟的方式,基于文献试验数据和材料参数,利用LS-DYNA软件对质量m=38.5g,φ12.7mm的平头和球头弹丸以V0=200~900m/s的初速分别正穿ht=1.6mm和ht=3.2mm厚的靶板进行了数值模拟研究,主要讨论了弹丸头部形状、初速以及靶板厚度对弹丸穿靶机理的影响,并分析了弹靶撞击的结构响应和材料响应,通过研究获得了上述因素弹丸穿靶机理影响的认识。主要结果如图1和图2(局部放大)所示。研究结果表明:

  • 标签: 弹丸 头部形状 薄钢靶 穿甲性能 数值模拟
  • 简介:Inthispaper,weinvestigatethetravelingwavesolutionsforthenonlineardispersiveequation,Korteweg-deVriesZakharov–Kuznetsov(KdV-ZK)equationandcomplexcoupledKdVsystembyusingextendedsimplestequationmethod,andthenderivethehyperbolicfunctionsolutionsincludesolitonsolutions,trigonometricfunctionsolutionsincludeperiodicsolutionswithspecialvaluesfordoubleparametersandrationalsolutions.Thepropertiesofsuchsolutionsareshownbyfigures.Theresultsshowthatthismethodisaneffectiveandapowerfultoolforhandlingthesolutionsofnonlinearpartialdifferentialequations(NLEEs)inmathematicalphysics.

  • 标签: EXTENDED simplest equation NONLINEAR DISPERSIVE eq