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16 个结果
  • 简介:TheconstitutiveequationforasemiconcentratedfibresuspensionintheOldroyd-Bfluidhasbeenderivedfromastatisticalmodelofsuchasuspensionbyemployingthemoleculartheoryforpolymericliquids.Tocircumventtheoreticaldifficultiesinviscoelasticfluidmechanics,severalsimplifiedmodelsareusedtoaccountfortheinteractionsoffibresandpolymermolecules.Someofmaterialfunctionsarecalculatedintermsoftheconstitutiveequation.

  • 标签: SUSPENSION CONSTITUTIVE equation material FUNCTIONS phase
  • 简介:ThispaperestablishesthevelocityfieldandtheadequateshearstresscorrespondingtothemotionofanOldroyd-BfluidbetweentwoinfinitecoaxialcircularcylindersbymeansoffiniteHankeltransforms.Theflowofthefluidisproducedbytheinnercylinderwhichappliesatime-dependentlongitudinalshearstresstothefluid.Theexactanalyticalsolutions,presentedinseriesformintermsofBesselfunctions,satisfyallimposedinitialandboundaryconditions.ThegeneralsolutionscanbeeasilyspecializedtogivesimilarsolutionsforMaxwell,secondgradeandNewtonianfluidsperformingthesamemotion.Finally,somecharacteristicsofthemotionaswellastheinfluenceofthematerialparametersonthebehaviorofthefluidmotionaregraphicallyillustrated.

  • 标签: COUETTE流动 流体运动 HANKEL变换 轴向 纵向剪应力 贝塞尔函数
  • 简介:TheintrinsicphysicalrelationshipofvorticitybetweenmodesAandBinthethree-dimensionalwaketransitionisinvestigated.Directnumericalsimulationsfortheflowpastasquare-sectioncylinderarecarriedoutatReynoldsnumbersof180and250,associatedwithmodesAandB,respectively.Basedontheanalysisofspacialdistributionsofvorticityinthenearwake,characteristicsoftheverticalvorticityinmodesAandBareidentified.Moreover,therelationshipofthreevorticitycomponentswithspecificsignsissummarizedintotwosignlaws,asintrinsicphysicalrelationshipsbetweentwoinstabilitymodes.Bythetheoryofvortex-inducedvortex,suchtwosignlawsconfirmthattherearetwoandonlytwokindsofvortex-sheddingpatternsinthenearwake,justcorrespondingtomodesAandB.Inbrief,alongthefreestreamdirection,modeAcanbedescribedbytheparallelsheddingverticalvorticeswiththesamesign,whilemodeBisdescribedbytheparallelsheddingstreamwisevorticeswiththesamesign.Finally,itisfoundoutthatthe-typevortexisabasickindofvortexstructureinbothmodesAandB.

  • 标签: MODE A MODE B WAKE Bluff
  • 简介:有沿着一张拉长的表的混合传送对流的非牛顿的液体的不可压缩的流动被分析。热转移现象通过热放射被讨论。融化的热转移和热产生/吸收的效果也被拿。合适的转变被利用达到非线性的平常的微分表情。会聚的系列答案被介绍。液体流动,温度,和表面热转移率图形地被检验。当时,松驰时间什么时候增加,被观察速度减少当延迟时间是不变的时,增加。当放射参数增加时,结果也表明温度分发减少。

  • 标签: magnetohydrodynamic (MHD ) Oldroyd-B 液体 混合传送对流 融化的热转移 热放射 加热产生 / 吸收
  • 简介:在laminar的非线性的传送对流的效果三维的Oldroyd-B液体流动被探讨。热转移现象被考虑非线性的热放射和热产生/吸收探索。边界层假设被考虑管理流动分析的数学模型。一些合适的类似变量被介绍把部分微分方程转变成平常的微分系统。有射击方法的Runge-Kutta-Fehlberg第四顺序、第五顺序的技术被用来获得无尺寸的速度和温度的答案。液体速度和温度上的各种各样的物理参数的效果被阴谋并且检验。比较与准确并且homotopy不安答案被做为粘滞液体大小写,和一根优秀火柴被注意。墙的数字价值砍在墙的压力和热转移率被公布并且调查。在德卜拉数字的价值的改进在液体速度上显示出反向的行为。当非线性的传送对流参数增加时,结果证明温度和热边界层被减少。Nusselt数字的价值比处于线性放射状况的那些处于非线性的放射状况是更高的。

  • 标签: 非线性的热传送对流 非线性的热放射 Oldroyd-B 液体 对流边界状况 热来源 / 水池 O361
  • 简介:Globallook-uptablestrategyproposedrecentlyhasbeenproventobeanefficientmethodtoacceleratetheinterpolation,whichisthemosttime-consumingpartintheiterativesub-pixeldigitalimagecorrelation(DIC)algorithms.Inthispaper,agloballook-uptablestrategywithcubicB-splineinterpolationisdevelopedfortheDICmethodbasedontheinversecompositionalGauss–Newton(IC-GN)algorithm.Theperformanceofthisstrategy,includingaccuracy,precision,andcomputationefficiency,isevaluatedthroughatheoreticalandexperimentalstudy,usingtheonewithwidelyemployedbicubicinterpolationasabenchmark.Thegloballook-uptablestrategywithcubicB-splineinterpolationimprovessignificantlytheaccuracyoftheIC-GNalgorithm-basedDICmethodcomparedwiththeoneusingthebicubicinterpolation,atatrivialpriceofcomputationefficiency.

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  • 简介:Lithium-aluminum-cobalt-nickeloxideLiAlxCoyNi1xyO2particles,generallyusedascathodeoflithiumbattery,werepreparedbychemicalcoprecipitationfromanaqueoussolutionofLiOH,Al(NO3)3,Co(NO3)2andNi(NO3)2withNH4OH.XRD,SEMandFTIRwereusedtoexaminetheeffectofnickelcontentontheproduct.FTIRpatternsshowedthatincreaseinnickelcontentdecreasedtheabsorptionstrengthofthepeakofspinelstructureoftheproduct,attributedtotheoccupationbynickelinthealuminumsites.Particlesizeandelectricalpropertiesofthelithium-aluminum-cobalt-nickeloxide(abbreviatedasLACNO)particleswerealsodetermined.

  • 标签: LiAlxCoyNi1-x-yO2 Chemical coprecipitation Particle size Electrical
  • 简介:The(2+1)-dimensionalBKPequationintheHirotabilinearformisstudiedduringthiswork.WronskianandGrammiantechniquesareappliedtotheconstructionofWronskianandGrammiansolutionsofthisequation,respectively.ItisshownthatthesesolutionscanbeexpressedasnotonlyPfaffiansbutalsoWronskiansandGrammians.

  • 标签: Wronski行列式 KP方程 双线性形式 可表
  • 简介:The1/3subharmonicsolutionfortheDuffing'sequationisinvestigatedbyusingthemethodsofharmonicbalanceandnumericalintegration.Thesensitivityofparametervariationforthetransientprocessandthetransientprocessfortheperturbanceinitialconditionsarestudied.Overandabove,theprecisionofnumericalintegrationmethodisdiscussedandthenumericalintegrationmethodiscomparedwiththeharmonicbalancemethod.Finally,asymptoticalstabilityofthepuresubharmonicoscillationselementisinspected.

  • 标签: Duffing' s EQUATION SUBHARMONIC TRANSIENT PROCESS
  • 简介:Inthispaper,ahigh-orderfinite-volumeschemeispresentedfortheone-dimensionalscalarandinviscidEulerconservationlaws.TheSimpson’squadratureruleisusedtoachievehigh-orderaccuracyintime.TogetthepointvalueoftheSimpson’squadrature,thecharacteristictheoryisusedtoobtainthepositionsofthegridpointsateachsub-timestagealongthecharacteristiccurves,andthethird-orderandfifth-ordercentralweightedessentiallynon-oscillatory(CWENO)reconstructionisadoptedtoestimatethecellpointvalues.Severalstandardone-dimensionalexamplesareusedtoverifythehigh-orderaccuracy,convergenceandcapabilityofcapturingshock.

  • 标签: EULER方程 有限体积格式 准一维 特征 基础 高阶精度
  • 简介:在现在的纸,包含三个任意的函数为的一个一般解决方案概括(2+1)维的KdV-mKdV方程,它被导出从概括(1+1)维的KdV-mKdV方程,首先借助于Wiess被介绍,小鼓,Carnevale(WTC)截断方法。然后有考虑的几条能量守恒定律的multisymplectic明确的表达被介绍为概括(2+1)维的KdV-mKdV方程基于桥的multisymplectic理论。随后,源于以便以Jacobi椭圆形的功能的合理功能模仿周期的波浪答案一般答案,一个半含蓄的multi-symplectic计划被构造那等价于Preissmann计划。从数字实验的结果,我们能断定multi-symplectic计划能精确地模仿周期的波浪答案概括(2+1)维的KdV-mKdV方程当时近似保存能量守恒定律。

  • 标签: KDV-MKDV方程 KDV-MKDV方程 广义 PREISSMANN格式 JACOBI椭圆函数 辛方法
  • 简介:AhighlyefficientH1-Galerkinmixedfiniteelementmethod(MFEM)ispresentedwithlineartriangularelementfortheparabolicintegro-differentialequation.Firstly,somenewresultsabouttheintegralestimationandasymptoticexpansionsarestudied.Then,thesuperconvergenceoforderO(h2)forboththeoriginalvariableuinH1(π)normandthefluxp=uinH(div,π)normisderivedthroughtheinterpolationpostprocessingtechnique.Furthermore,withthehelpoftheasymptoticexpansionsandasuitableauxiliaryproblem,theextrapolationsolutionswithaccuracyO(h3)areobtainedfortheabovetwovariables.Finally,somenumericalresultsareprovidedtoconfirmvalidityofthetheoreticalanalysisandexcellentperformanceoftheproposedmethod.

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  • 简介:针对1点RANSAC(RandomSampleConsensus)单目视觉EKF(ExtendedKalmanFilter)算法中的滤波发散问题,分析了滤波发散的产生原因,提出了一种基于渐消记忆滤波的1点RANSAC单目视觉姿态估计算法。该算法通过在EKF滤波方程中引入加权因子,逐渐加大当前数据的权重,相应地减少旧数据的权重,有效地扼制了算法中的滤波发散问题。最后通过两组验证性实验验证说明了算法的有效性。实验结果表明:该算法能够有效地解决1点RANSAC单目视觉EKF算法中的滤波发散问题,具有更高的精度。第一组双轴联动实验,航向角的平均误差减小2.4158?,俯仰角平均误差减小0.1782?;第二组偏航轴大角度转动实验,摄像机航向角的估计误差一直保持在1.5?以内。

  • 标签: 1点RANSAC算法 渐消记忆滤波 单目视觉 滤波发散
  • 简介:Perovskite-typeLa1-xCexMnO3(x=0-10%)catalystswerepreparedbyflamespraypyrolysisandtheiractivitiesduringthecatalyticoxidationofbenzenewereexaminedoverthetemperaturerangeof100-450℃.ThestructuralpropertiesandreducibilityofthesematerialswerealsocharacterizedbyX-raydiffraction(XRD),N2adsorption/desorption,H2temperature-programmedreduction(H2-TPR)andX-rayphotoelectronspectroscopy(XPS).TheincorporationofCewasfoundtoimprovethebenzeneoxidationactivity,andtheperovskiteinwhichxwas0.1exhibitedthehighestactivity.Phasecompositionandsurfaceelementalanalysesindicatedthatnon-stoichiometriccompoundswerepresent.TheincorporationofCehadanegligibleeffectonthespecificsurfaceareaoftheperovskitesandhencethisfactorhaslittleimpactonthecatalyticactivity.IntroductionofCe44+resultedinmodificationofthechemicalstatesofbothB-siteionsandoxygenspeciesandfacilitatedthereducibilityoftheperovskite.ThesurfaceMn4+/Mn3+ratiowasincreasedasaresultofCe4+substitution,whileadecreaseinthesurface-adsorbedO/latticeO(Oads/Olatt)ratiowasobserved.Therelationshipbetweenthesurfaceelementalratiosandcatalyticactivitywasestablishedtoallowabetterunderstandingoftheprocessbywhichbenzeneisoxidizedoverperovskites.

  • 标签: 钙钛矿型 氧化铈 催化剂 掺入 火焰 X射线光电子能谱
  • 简介:阴极材料李[CoxNiyMn1?x?y]为锂的O2第二等的电池被一条新线路作为一位先锋用分层的双氢氧化物(LDH)准备了。结果有-NaFeO2结构的分层的阶段在菱形的系统结晶,与有到0.47nm的夹层间距结束的空格组R-3m。X光检查光电子光谱学(XPS)被用来测量公司,Ni和Mn的氧化状态。在结构和李的电气化学的性质上改变Co/Ni/Mn比率的效果[CoxNiyMn1?x?y]O2被X光检查衍射和电气化学的测试调查了。产品表明了相当稳定的骑车行为,与为有Co/Ni/Mn=1/1/1的分层的材料的118mAh/g的一个可逆能力。

  • 标签: 层状正极材料 层状双金属氢氧化物 层状前体 O2 X射线光电子能谱 合成