学科分类
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500 个结果
  • 简介:为在一个三维的围住的领域的不可压缩的二进制液体混合物的进化的二个不同模型被考虑。他们由3D组成不可压缩的海军司烧方程,使外部力量遭到到时间依赖者并且结合了一个对流Allen-Cahn或Cahn-Hilliard方程。如此的系统能被看作海军司烧方程的归纳到二阶段的液体。用轨道途径,作者为两个系统证明轨道引起注意的人的存在。

  • 标签: 流体混合物 三维轨迹 吸引子 STOKES方程 二元 不可压缩
  • 简介:X-rayimagingistheconventionalmethodfordiagnosingtheorthopedicconditionofapatient.ComputerizedTomography(CT)scanningisanotherdiagnosticmethodthatprovidespatient’s3Danatomicalinformation.However,bothmethodshavelimitationswhendiagnosingthewholeleg;X-rayimagingdoesnotprovide3Dinformation,andnormalCTscanningcannotbeperformedwithastandingposture.Obtaining3Ddataregardingthewholeleginastandingpostureisclinicallyimportantbecauseitenables3Danalysisintheweightbearingcondition.Basedontheseclinicalneeds,ahardware-basedbi-planeX-rayimagingsystemhasbeendeveloped;itusestwoorthogonalX-rayimages.However,suchmethodshavenotbeenmadeavailableingeneralclinicsbecauseofthehightcost.Therefore,weproposedawidelyadaptivemethodfor2DX-rayimageand3DCTscandata.Bythismethod,itispossibletothreedimensionallyanalyzethewholeleginstandingposture.TheoptimalpositionthatgeneratesthemostsimilarimageisthecapturedX-rayimage.Thealgorithmverifiesthesimilarityusingtheperformanceoftheproposedmethodbysimulation-basedexperiments.Then,weanalyzedtheinternal-externalrotationangleofthefemurusingrealpatientdata.Approximately10.55degreesofinternalrotationswerefoundrelativetothedefinedanterior-posteriordirection.Inthispaper,wepresentausefulregistrationmethodusingtheconventionalX-rayimageand3DCTscandatatoanalyzethewholelegintheweight-bearingcondition.

  • 标签: 2D-3D REGISTRATION 3D analysis X-RAY CT
  • 简介:这份报纸被奉献给考虑三维粘滞大规模空气的原始方程。首先,我们比那与更弱的起始的数据为原始方程证明全球well-posedness在[11]。第二,我们获得方程的光滑的答案的存在。而且,我们为大规模空气的原始方程产生的动态系统在V获得紧缩的全球引起注意的人,它改进结果[11]。

  • 标签: 原始方程 三维粘性 大气 原始数据 动力系统 全局吸引
  • 简介:讨论一种合理的绿色机房模型,求出了在不同的任务量、分配方式、空调风速和空调温度下机房的平均温度、热点、以及热分布和气流速度分布图。分别用人工神经网络和模拟仿真软件Airpak软件建立模型分析空调的热分布。通过在Airpak中更改机柜发热功率、空调的送风温度、送风速度来模拟仿真不同情况下机房的热循环过程。最后进行改进和优化,使其能够适应更多情况和条件。

  • 标签: 绿色机房 热分布 流场分布 插值 AIRPAK 有限体积法
  • 简介:InthispaperwestudythecomputationalperformanceofvariantsofanalgebraicadditiveSchwarzpreconditionerfortheSchurcomplementforthesolutionoflargesparselinearsystems.Inearlierworks,thelocalSchurcomplementswerecomputedexactlyusingasparsedirectsolver.Therobustnessofthepreconditionercomesatthepriceofthismemoryandtimeintensivecomputationthatisthemainbottleneckoftheapproachfortacklinghugeproblems.InthisworkweinvestigatetheuseofsparseapproximationofthedenselocalSchurcomplements.TheseapproximationsarecomputedusingapartialincompleteLUfactorization.Suchanumericalcalculationisthecoreofthemulti-levelincompletefactorizationsuchastheoneimplementedinpARMS.Thenumericalandcomputingperformanceofthenewnumericalschemeisillustratedonasetoflarge3Dconvection-diffusionproblems;preliminaryexperimentsonlinearsystemsarisingfromstructuralmechanicsarealsoreported.

  • 标签: 稀疏逼近 三维 代数 求解器 舒尔补 SCHUR补
  • 简介:Inthispaper,weconsidertheblow-upofsmoothsolutionstothe3DidealMHDequations.Let(u,b)beasmoothsolutionin(0,T).Itisprovedthatthesolution(u,b)canbeextendedaftert=Tif(↓Δ×u,↓Δ×b)∈L^1(0,T;B∞,∞^0).ThisisanimprovementoftheresultgivenbyCaflisch,Klapper,andSteele.

  • 标签: MHD方程 磁场 流速 比绍夫空间 光滑解 偏微分方程
  • 简介:这篇论文为3D在一张无穷地长圆柱的嘴在亚声的流动的全球存在和稳定性上涉及这个问题稳定的潜在的流动方程。如此的一个问题被Courant-Friedrichs显示在[8,p。377]:通过管的流动应该是被考虑一稳定,isentropic,无旋与圆柱的对称流动并且应该由与适当边界条件解决3D潜力流动方程坚定。由介绍一些合适加权的H?lder空格并且建立priori估计,当在否定无穷的亚声的流动的国家被给时,作者在一张3D嘴证明亚声的潜在的流动的全球存在和稳定性。关键词亚声的流动-潜在的流动方程-Bessel功能-加权的H?lder空格-全球存在2000苏布杰克特先生分类35L70-35L65-35L67-国家Basic支持的76N15工程中国(号码2006CB805902)的研究节目,中国(号码10871096)的国家自然科学基础和为江苏大学的先进才能的研究基础。

  • 标签: 稳定性问题 亚音速流动 无限长 三维 喷嘴 圆柱
  • 简介:TheexistenceandorbitalinstabilityofstandingwavesforthegeneralizedthreedimensionalnonlocalnonlinearSchr¨odingerequationsisstudied.Bydefiningsomesuitablefunctionalsandaconstrainedvariationalproblem,wefirstestablishtheexistenceofstandingwaves,whichrelysontheinnerstructureoftheequationsunderconsiderationtoovercomethedrawbackthatnonlocaltermsviolatethespace-scaleinvariance.Wethenshowtheorbitalinstabilityofstandingwaves.Theargumentsdependupontheconservationlawsofthemassandoftheenergy.

  • 标签: 薛定谔方程组 不稳定性 非线性SCHRODINGER方程 局部非线性 轨道 三维
  • 简介:Segmentationofthree-dimensional(3D)complicatedstructuresisofgreatimportanceformanyrealapplications.Inthisworkwecombinegraphcutminimizationmethodwithavariantofthelevelsetideafor3DsegmentationbasedontheMumford-Shahmodel.ComparedwiththetraditionalapproachforsolvingtheEuler-Lagrangeequationwedonotneedtosolveanypartialdifferentialequations.Instead,theminimumcutonaspecialdesignedgraphneedtobecomputed.Themethodistestedondatawithcomplicatedstructures.Itisratherstablewithrespecttoinitialvalueandthealgorithmisnearlyparameterfree.Experimentsshowthatitcansolvelargeproblemsmuchfasterthantraditionalapproaches.

  • 标签: 水平集方法 三维分割 分段常数 多相 拉格朗日方程 传统方法
  • 简介:Inthispaper,westudytheCauchyproblemforthe3DgeneralizedNavier-Stokes-Boussinesqequationswithfractionaldiffusion:{ut+(u·▽)u+v∧2αu=-▽p+θe(3),e3=(0,0,1)T,θt+(u·▽)θ=0,Dicu=0.Withthehelpofthesmoothingeffectofthefractionaldiffusionoperatorandalogarithmicestimate,weprovetheglobalwell-posednessforthissystemwithα≥5/4.Moreover,theuniquenessandcontinuityofthesolutionwithweakerinitialdataisbasedonFourierlocalizationtechnique.Ourresultsextendonesonthe3DNavier-Stokesequationswithfractionaldiffusion.

  • 标签: BOUSSINESQ方程 整体适定性 广义 三维 分数阶 柯西问题
  • 简介:Inthisnote,wewillgiveanewproofoftheblow-upcriterionofsmoothsolutionstothe3Dincompressiblemagneto-hydrodynamicequationsbyasimpleapplicationofGagliardo-Nirenberg’sinequality.

  • 标签: 不可压缩 BLOW-UP 光滑解 MHD方程 三维 标准
  • 简介:在这篇文章,我们为3D建立准确答案到Cauchy问题球状地对称的不可压缩的海军司烧方程和进一步的学习答案的存在和asymptotic行为。

  • 标签: 不可压缩 CAUCHY 方程 海军 对称 球状
  • 简介:Inthisworkweconsidertheproblemofshapereconstructionfromanunorganizeddatasetwhichhasmanyimportantapplicationsinmedicalimaging,scientificcomputing,reverseengineeringandgeometricmodelling.ThereconstructedsurfaceisobtainedbycontinuouslydeforminganinitialsurfacefollowingthePartialDifferentialEquation(PDE)-baseddiffusionmodelderivedbyaminimalvolume-likevariationalformulation.Theevolutionisdrivenbothbythedistancefromthedatasetandbythecurvatureanalyticallycomputedbyit.Thedistancefunctioniscomputedbyimplicitlocalinterpolantsdefinedintermsofradialbasisfunctions.SpacediscretizationofthePDEmodelisobtainedbyfiniteco-volumeschemesandsemi-implicitapproachisusedintime/scale.Theuseofalevelsetmethodforthenumericalcomputationofthesurfacereconstructionallowsustohandlecomplexgeometryandevenchangingtopology,withouttheneedofuser-interaction.Numericalexamplesdemonstratetheabilityoftheproposedmethodtoproducehighqualityreconstructions.Moreover,weshowtheeffectivenessofthenewapproachtosolveholefillingproblemsandBooleanoperationsbetweendifferentdatasets.

  • 标签: Partial Differential Equation surface reconstruction numerical
  • 简介:Inthispaper,weinvestigatetheglobalexistenceandlongtimebehaviorofstrongsolutionsforcompressiblenematicliquidcrystalflowsinthreedimensionalwholespace.TheglobalexistenceofstrongsolutionsisobtainedbythestandardenergymethodundertheconditionthattheinitialdataareclosetotheconstantequilibriumstateinH~2-framework.IftheinitialdatasinL~1-normarefiniteadditionally,theoptimaltimedecayratesofstrongsolutionsareestablished.WiththehelpofFouriersplittingmethod,onealsoestablishesoptimaltimedecayratesforthehigherorderspatialderivativesofdirector.

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