学科分类
/ 1
16 个结果
  • 简介:ObjectivePorencephaliccystpresentingwithotologicinvolvementisuncommon.Onlyafewcaseshavebeenreported.Wereportararecaseofcerebrospinalfluid(CSF)otorrheacausedbyamassiveporencephaliccystencompassingthelefttemporalandoccipitallobes.TheCSFleakwasrepairedsuccessfullyusingatransmastoidapproachwithfacia,abdomenfatandfibringluetosealtheosseousdefectsinthesinoduralangle.AreviewoftheliteratureconcerningporencephaliccystandCSFotorrheaisalsopresented.

  • 标签: 文献综述 脑脊液 囊肿 病例报告 纤维蛋白胶 脑脊髓液
  • 简介:wellposedness问题为一各向异性不可压缩粘滞在3的液体,在向量B附近旋转(t,x):=(b1(t,x),b2(t,x),b3(t,x)),被学习。在同类的案例中的全球wellposedness(B=e3)与在空间B0的足够地快的旋转,?被证明。在不同类的案例中(B=B(t,xh)),在B0的答案的全球存在和唯一,?被获得,如果起始的数据是足够的与水平粘性相比小。而且,我们在一样的函数空格获得解决方案的一致本地存在和唯一。我们也在B2,1获得整齐的繁殖吗?在另外的假设下面,那B仅仅取决于一个水平空间变量。

  • 标签: 各向异性 适定性 流体方程 旋转 不可压缩粘性流体 功能空间
  • 简介:Osteocytesactasmechanosensorsinbone,whichcansendmechanicalsignalsdirectlytoosteoblaststhroughgapjunctions.However,underphysiologicalconditionsthenumberofgapjunctionsislimitedbecauseofthequantityvarianceofthetwokindsofcells.Inthisstudy,thepossibilityofindirectinteractionbetweenthesetwocellswasinvestigated.Anewflowchamperwasdesignedinwhichosteocytesandosteoblastswerecoculturedintwochampersseparately.OsteocyteswereexposedtofluidflowandthentheALPactivity,osteocalcinandosteopotinofosteoblastsweredetermined.TheresultsshowedthateitherALPactivityorproductionofosteocalcinandosteopotininosteoblaststhatwerecoculturedwithshearedosteocytesincreased,whichindicatedthatosteocytescouldregulateosteoblastsindirectlythroughsomesolublefactors.

  • 标签: 生物医学工程 人工脏器 人工器官 生物力学
  • 简介:Vibrationofacircularmembraneincontactwithafluidhasextensiveapplicationsinindustry.Thenaturalvibrationfrequenciesfortheasymmetricfreevibrationofacircularmembraneincontactwithaboundedincompressiblefluidarederivedinthispaper.Consideringsmalloscillationsinducedbythemembranevibrationinanincompressibleandinviscidfluid,thevelocitypotentialfunctionisusedtodescribethefluidfield.Twoapproachesareusedtoderivethefreevibrationfrequenciesofthesystem,whichincludeavariationalformulationandanapproximatesolutionemployingtheRayleighquotientmethod.Agoodcorrelationisfoundbetweenfreevibrationfrequenciesevaluatedbythesemethods.Finally,theeffectsofthefluiddepth,themassdensity,andtheradialtensiononthefreevibrationfrequenciesofthecoupledsystemareinvestigated.

  • 标签: 不可压缩流体 自由振动频率 振动膜 固有振动频率 速度势函数 粘性流体
  • 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:Toanalyzeanddepictcomplicatedfluidbehaviorsinfracturedporousmediawithvariablypermeablematrix,anintegrateddiscretecomputationalalgorithmisproposedbasedonlatticeBoltzmannmethod(LBM).Thispapercombineswiththeexternalforcemodelandstatisticalmaterialphysicstoeffectivelydescribethefeaturechangeswhilethefluidpassesthroughthefractureswithinthepermeablematrix.Asanapplicationexample,atwodimensionalrocksampleisreconstructedusingthedigitalimageandcharacterizedwithdifferentfeaturevaluesateachLBMgridtodistinguishpores,impermeableandpermeablematrixbystatingitslocalphysicalproperty.ComparedwiththeconventionalLBM,theresultsdemonstratetheadvantagesofproposedalgorithminmodelingfluidflowphenomenoninfracturedporousmediawithvariablypermeablematrix.

  • 标签: LBM模拟 矩阵算法 多孔介质 流体流动 格子BOLTZMANN方法 裂隙
  • 简介:Takingextractionrateasanindicator,theextractiontechnologyofChinese-firheartwoodbysupercriticalcarbondioxidetreatmentwasstudied,andtheextractionrateoftheSFE-CO2methodwascomparedtothatoftraditionalextractionmethod.Theresultsshowthatwhenextractionprocessingconditionwere:extractionpressure30MPa,extractiontemperature40℃,extractiontime120m,andflowvelocity20kg/h,theextractionrateofSFE-CO2was0.99%,0.20%morethanthatofthetraditionalextractionmethod.However,takingthecostintoconsideration,itisproposedthatthetraditionalextractionisusedunlesstherearespecificrequirements.

  • 标签: Cunninghamia lanceolata(Lamb.) HOOK essential oil SUPERCRITICAL
  • 简介:为了提供,身体上在地区性的规模为风侵蚀研究基于风建模,3D计算液体动力学(CFD)风模型被开发。模型基于海军司烧方程用C语言被规划,并且它作为开放源代码自由地可得到。与空间分析和建模工具(SAMT)综合,风模型举办方便输入准备和强大的产量可视化。为了验证风模型,,一系列实验在一条风隧道被进行。一个堵住的流入实验被设计在基本液体进程的模拟上测试模型的性能。一个圆障碍实验被设计检查模型是否能在风地上模仿障碍的影响。结果证明测量并且模仿的风地有高关联,和风模型能两个都模仿风的基本过程和对风地的障碍的影响。这些结果显示出风模型的高可靠性。一个区域的一个数字举起模型(DEM)(长的3800m和1700m宽)在在内部蒙古的Xilingele草地(自治区域,中国)被用于模型,和一块3D风地成功地被产生了。由风隧道实验的模型和足够的确认的清楚的实现在地区性的规模为风侵蚀的预言和评价打了一个稳固的基础。

  • 标签: 风模型 计算液体动力学(CFD ) 风侵蚀 风隧道实验 空间分析和建模工具(SAMT ) 开放源代码
  • 简介:Ananalyticalmodelisdevelopedtostudythesurfaceeffectsonthevibrationbehaviorincludingthenaturalfrequencyandthecriticalflowvelocityoffluid-conveyingnanotubesembeddedinanelasticmedium.TheeffectsofsurfaceelasticityandresidualsurfacestressareaccountedthroughthesurfaceelasticitymodelandtheYoung-Laplaceequation.AWinkler-typefoundationisemployedtomodeltheinteractionofnanotubesandthesurroundingmedium.Theresultsshowthatthesurfaceeffectshavemoreprominentinfluencesonthenaturefrequencywithsmallernanotubethickness,largeraspectratioandlargerelasticmediumconstants.Bothsurfacelayersandtheelasticmediumenhancethestabilityofnanotubes.Thisstudymightbehelpfulfordesigningthefluid-conveyingnanotubedevicesinNEMSandMEMSsystems.

  • 标签: 弹性介质 碳纳米管 表面效应 流体输送 振动分析 嵌入
  • 简介:从地下的管子的漏能导致被破坏并且引起损坏到邻近的基础结构的基础。包围漏的区域的土壤粒子能从由漏的液体的土壤矩阵被动员,代替,并且甚至洗了,产生虚空或洞。用acoupled的二维的模拟分离元素方法和格子Boltzmann方法(DEMLBM)被用来调查一个土壤床题目的行为到局部地注射的液体,它在一根管子中代表一条漏缝。内部粒子的表面精力的各种各样的价值也被采用为连贯的粒子的机械效果建模。结果建议内部粒子的表面精力极大地关于漏的液体影响床反应,包括开始洞,洞形状和它的进化率的过量压力。

  • 标签: 土壤颗粒 注射液 格子BOLTZMANN方法 行为 二维 管道泄漏
  • 简介:Atwo-dimensional(2D)numericalmodelisdevelopedforthewavesimulationandpropagationinawaveflume.Thefluidflowisassumedtobeviscousandincompressible,andtheNavier-Stokesandcontinuityequationsareusedasthegoverningequations.Thestandardk-εmodelisusedtomodeltheturbulentflow.TheNavierStokesequationsarediscretizedusingthestaggeredgridfinitedifferencemethodandsolvedbythesimplifiedmarkerandcell(SMAC)method.Wavesaregeneratedandpropagatedusingapistontypewavemaker.Anopenboundaryconditionisusedattheendofthenumericalflume.Somestandardtests,suchasthelid-drivencavity,theconstantunidirectionalvelocityfield,theshearingflow,andthedam-breakonthedrybed,areperformedtovalidthemodel.Todemonstratethecapabilityandaccuracyofthepresentmethod,theresultsofgeneratedwavesarecomparedwithavailablewavetheories.Finally,theclusteringtechnique(CT)isusedforthemeshgeneration,andthebestconditionissuggested.

  • 标签: 数值波浪水槽 Navier-Stokes方程 非线性波 流体体积法 集群技术 有限差分方法
  • 简介:Intheunderwater-shockenvironment,cavitationoccursnearthestructuralsurface.Thedynamicresponseoffluid-structureinteractionsisinfluencedseriouslybythecavitationeffects.Itisalsothedifficultyinthefieldofunderwaterexplosion.Withthetraditionalboundaryelementmethodandthefiniteelementmethod(FEM),itisdifficulttosolvethenonlinearproblemwithcavitationeffectssubjectedtotheunderwaterexplosion.Tosolvethisproblem,undertheconsiderationofthecavitationeffectsandfluidcompressibility,withfluidvisciditybeingneglected,a3Dnumericalmodeloftransientnonlinearfluid-structureinteractionsubjectedtotheunderwaterexplosionisbuilt.Thefluidspectralelementmethod(SEM)andtheFEMareadoptedtosolvethismodel.AftercomparisonwiththeFEM,itisshownthattheSEMismoreprecisethantheFEM,andtheSEMresultsareingoodcoincidencewithbenchmarkresultsandexperimentresults.Basedonthis,combinedwithABAQUS,thetransientfluid-structureinteractionmechanismofthe3Dsubmergedsphericalshellandshipstiffenedplatessubjectedtotheunderwaterexplosionisdiscussed,andthecavitationregionanditsinfluenceonthestructuraldynamicresponsesarepresented.Thepaperaimsatprovidingreferencesforrelevantresearchontransientfluid-structureinteractionofshipstructuressubjectedtotheunderwaterexplosion.

  • 标签: 结构相互作用 三维数值模型 水下爆炸 拟流体 气蚀 有限元法
  • 简介:Thebasic-nitrogenaromaticcompoundsinfeedstocksandliquidproductsfromthemicro-reactorandsolublecomponentsofcokeobtainedduringfluidcatalyticcracking(FCC)processwereanalyzedbythemicro-electrosprayionization(ESI)9.4TFouriertransformioncyclotronresonancemassspectrometry(FT-ICRMS)withanaveragemassresolvingpowerof300000atamassrangeof100-1200.Theanalyticalresultsrevealedthatthecokergasoil(CGO)containedahigherabundanceofbasic-nitrogenaromaticcompoundswiththetypeof-5Nto-9Ncomparedwiththoseindeasphaltedoil(DAO)andmixedFCCfeedstock.Aftercatalyticcracking,theabundanceoflowlycondensedbasic-nitrogenaromaticcompoundswasmuchlessthanthoseofhighlycondensedaromaticsintheliquidproducts,withthecarbonnumbermainlyrangingfrom6to25andtheaveragecarbonnumberoftheside-chainsequatingto1-5.Onthecontrary,withrespecttothesolublecomponentsofcoke,theabundanceoflowlycondensedbasic-nitrogenaromaticcompoundswasmorethanthoseofhighlycondensedaromatics,andthecarbonnumberrangedfrom12to30,whichwasmuchsmallerthanthatofthemixedFCCfeedstockbutslightlylargerthanthatofthecrackedliquidproducts.TheseresultshaveprovidedsomefundamentalinformationonFCCprocess.

  • 标签: 离子回旋共振 催化裂化过程 傅立叶变换 碱性氮 质谱 FCC原料