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500 个结果
  • 简介:A3D非静水力学的模型葡萄(全球/地区性的吸收和预言系统)的动态核心在Yin-Yang格子上被开发处理极的问题并且提高计算效率。强迫的三维的Coriolis被介绍给新核心,并且强迫的Coriolis的完整的表示使分享在殷和杨子域之间的代码直接。类似于在葡萄建模的原版,一个半含蓄的semi-Lagrangian计划与跨边界的运输的另外的安排为时间的集成和移流被采用。在时间的非集中的秒顺序和空间discretization下面,干燥nonhydrostatic框架作为一个椭圆的问题的答案被总结。产生Helmholtz方程被解决与概括与经典Schwarz方法在合作结合剩余解答者。尽管方程的系数与在原来的模型的那些相当不同,新核心的计算过程只是一样。双性人立方的Lagrangian插值服务向Dirichlet类型边界条件提供在子域之间的数据转移。干燥核心与几个基准测试用例被评估,并且所有测试显示合理数字稳定性和计算性能。平衡流动的坚持和导致山脉的Rossby波浪和Rossby-Haurwitz波浪的开发在半含蓄的semi-Lagrangian证实3DCoriolis条款的适当安装Yin-Yang格子上的动态核心。

  • 标签: 非静力模式 模型系统 阴阳 GRAPES模式 亥姆霍兹方程 Rossby波
  • 简介:Thethree-dimensionalNavier-Stokesequationsweresolvedwiththefractionalstepmethodwherethehydrostaticpressurecomponentwasdeterminedfirst,whilethenon-hydrostaticcomponentofthepressurewascomputedfromthepressurePoissonequationinwhichthecoefficientmatrixispositivedefiniteandsymmetric.Theeddyviscositywascalculatedfromtheefficientk-εturbulencemodel.TheresultingmodeliscomputationallyefficientandunrestrictedtotheCFLcondition.Computationswithandwithouthydrostaticapproximationwerecomparedforthesamecasestotestthevalidityoftheconventionalhydrostaticpressureassumption.Themodelwasverifiedagainstanalyticalsolutionsandexperimentaldata,withexcellentagreement.

  • 标签: 网栅 流体静力学 湍流 自由表面流
  • 简介:喷雾器光性质被模仿用光谱为喷雾器种类(SPRINTARS)的放射运输模型结合了非静水力学的ICosahedral大气的模型(NICAM)。3年的全球吝啬的所有天空喷雾器在550nm的光厚度(AOT),?ngstr?m代表(AE)分别地在0.123,0.657和0.944点基于在440和870nm,和在550nm的单个散布反照率(SSA)的AOT被估计。为每喷雾器种,吝啬的AOT在AeroCom模型的范围以内。建模的所有天空和清楚天空的结果与从中等分辨率成像分光辐射函数(MODIS)和喷雾器机器的网络(AERONET)的观察相比。所有天空AOT的模仿的空间与时间的分布能通常复制MODIS检索,和关联和模型技巧能稍微在大多数陆地区域上用清楚天空的结果被改进。之间的差别清楚天空并且所有天空AOT在弄脏的区域上是更大的。与从AERONET的观察相比,建模并且观察的所有天空AOT和AE通常在合理同意,而SSA变化很好没被捕获。尽管所有天空和清楚天空的结果的空间与时间的分布是类似的,清楚天空的结果更好通常与观察被相关。清楚天空的AOT和SSA比所有天空结果的通常低,特别在喷雾器化学药品作文主要被硫酸盐喷雾器贡献的那些区域。建模的清楚天空的AE比在吸水的喷雾器统治的那些区域上的所有天空AE大,当反面在恐水病的喷雾器统治的区域上被发现时。

  • 标签: 气溶胶光学厚度 模式模拟 光学特性 二十面体 大气模式 非静力
  • 简介:Asemi-implicit3-Dnumericalformulationforsolvingnon-hydrostaticpressurefree-surfaceflowsonanunstructured,sigmagridisproposed.Pressure-splittingand9semi-implicitmethodsareinheritedandreformedfromCasulli'sz-coordinateformulation.Thenon-orthogonalsigma-coordinatetransformationleadstoadditionalterms.Theresultinglinearsystemforthenon-hydrostaticcorrectionisdiagonallydominantbutunsymmetric,anditissolvedbytheBiCGstabmethod.Incontrastwithz-coordinatenon-hydrostaticmodels,thenewmodelfitsverticalboundariesmuchbetter,whichisimportantforthelong-timesimulationofsedimenttransportandriverbeddeformation.Alock-exchangedensityflowiscomputedtodeterminewhetherthenewschemeisabletosimulatenon-hydrostaticfree-surfaceflows.ThenewmodelisfurtherverifiedusingthefielddataofanaturalriverbendofthelowerYangtzeRiver.Goodagreementbetweensimulationsandearlierresearchresults,fielddataisobtained,indicatingthatthenewmodelisapplicabletohydraulicprojectsinrealrivers.

  • 标签: 三维数值模型 自由表面流动 静水压力 非结构化 半隐式 电网
  • 简介:A3-DnumericalformulationisproposedonthehorizontalCartesian,verticalsigma-coordinategridformodelingnon-hydrostaticpressurefree-surfaceflows.Thepressuredecompositiontechniqueandθsemi-implicitmethodareused,withthesolutionprocedurebeingsplitintotwosteps.First,withtheimplicitpartsofnon-hydrostaticpressuresexcluded,theprovisionalvelocityfieldandfreesurfaceareobtainedbysolvinga2-DPoissonequation.Second,thetheoryofthedifferentialoperatorisemployedtoderivethe3-DPoissonequationfornon-hydrostaticpressures,whichissolvedtoobtainthenon-hydrostaticpressuresandtoupdatetheprovisionalvelocityfield.Whenthenon-orthogonalsigma-coordinatetransformationisintroduced,additionaltermscomeintobeing,resultingina15-diagonal,diagonallydominantbutunsymmetriclinearsysteminthe3-DPoissonequationfornon-hydrostaticpressures.TheBiconjugateGradientStabilized(BiCGstab)methodisusedtosolvetheresulting3-Dunsymmetriclinearsysteminsteadoftheconjugategradientmethod,whichcanonlybeusedforsymmetric,positive-definitelinearsystems.Threetestcasesareusedforvalidations.Thesuccessfulsimulationsofthesmall-amplitudewave,asupercriticalflowoverarampandaturbulentflowintheopenchannelindicatethatthenewmodelcansimulatewellnon-hydrostaticflows,supercriticalflowsandturbulentflows.

  • 标签: 三维数值模型 自由表面流 静水压力 坐标变换 半隐式 非对称线性系统
  • 简介:Compositediaphragminflation(CDI)experimentisausefulmethodologyforexploringthemechanicsrelationofcell-celljunctionswithinalivingepithelialsheet.Inthispaper,anewmethodologyofCDIexperimenthasbeenputforward.Thefinitedeformationofacircularpolydimezhylsiloxaneelastomericmembrane,whichisusedasthesubstrateforthecultureofepithelialcells,underhydrostaticpressureisexploredbythetheoryofnon-linearcontinuummechanics.Thesimplifiedgoverningequationswithminimumamountofdifferentialequationsandboundaryconditionsareobtainedandsolvedbymultipleshootingmethod.Theinfluencesonthemembranebyhydrostaticpressurehavebeendiscussed.

  • 标签: 通货膨胀率 弹性膜片 静水压力 圆形 上皮细胞 力学关系
  • 简介:ThroughanalysisandnumericalcomputationofECMWF’sdiscreteschemeofhydrostaticequation(Baedeetal.1979),ithasbeenfoundthatinthecaseofequal△σthereexistsystematicerrorsinthescheme.TheerrorE(?)causedbytakingthearithmeticmeanofthegeopotentialheightsoftwoadjacenthalfa-levelsasthegeopotentialheightofthecor-respondingintegera-level,increaseswithheightandhasanunacceptablemaximuminthevicinityofthetopoftheat-mosphere;however,theerrorscausedbythetemperaturetreatmentaregenerallysmall.Ontheotherhand,ifanuneven△σ-schemeinwhichthelevelsintheupperandloweratmospherearedenserthanthoseinthemiddleatmosphere,isadopted,thenE(?)canbemuchreduced.However,iftheresolutionoftheoriginalequalArt-schemedoubles,thenE(?)canonlybefoundtobemuchreducedinthetroposphereandthatinthevicinityoftheatmospherictopisstillunacceptable.Twonumericalschemesforimprovementhavebeenpresented.OfthemoneisthesameastheECMWF’sscheme,butwithequal△lnσ,andtheotheristointegratetheequationbytheuseofTschebyscheffpolynomialsTandtoadoptthezerosofTNastheatmosphericlevelswhereNisthetotalnumberoflevels.Theresultsshowthatwithbothschemesthecomputationalerrorscanbemuchreduced,especiallythelatter,duetothefactthattheerrorsofthreestatisticaltypesaregenerallylessthantherootmeansquareerrorofthegeopotentialheightsreportedinTEMP.

  • 标签: HYDROSTATIC EQUATION VERTICAL DISCRETIZATION Tschebyscheff POLYNOMIALS
  • 简介:Alaskapollockisanimportantproteinsourcewhichisextensivelyusedinthefoodindustry.Pollockproteinisolates(PPI)withsignificantlyenrichedproteincontentscouldbepreparedusingisoelectricsolubilization/precipitation(ISP)processing;however,thefunctionalpropertiesofthisprocessislimitedbythelargeamountofwater-insolubleproteins.Inthisstudy,weinvestigatedtheinfluenceofhighhydrostaticpressure(HHP)treatmentonthesolubilityandstructuralchangesofPPI.PPIobtainedusingISPistreatedwithhydrostaticpressuresof200,300,400,and500MPaforupto15min,andtheHHP-treatedsampleswereobservedtoexhibitsignificantlyimprovedsolubilities.FurtherbiochemicalassaysrevealthatthecontinuousHHPtreatmentsreducethecontentsoffreesulfhydrylgroupsandpromotetheformationofmacromoleculeswithbetterwatersolubilities,whichmayinducethesolubilityimprovementsoftheHHP-treatedPPI.OurresultsindicatethatHHPcanbeutilizedtoeffectivelypreparehighlywater-solubleAlaskapollockproteininfoodprocessing.

  • 标签: Alaska POLLOCK PROTEIN isolate(PPI) SOLUBILITY high
  • 简介:SplitTrailingSuctionHopperDredgers(TSHD)arespecialtypeofworkingships,whosehullsopentodischargecargotocertainunloadingpositionswhilebeingatsea.Althoughtheyhavevariablehullgeometry,theirhydrostaticandstabilitycharacteristicsareusuallycalculatedforunchangedinitialhullgeometryloadingconditionsonly,andsuchcalculationsaresupportedbyclassificationsocietystabilityregulationsforthatshiptype.Nevertheless,inthisstudy,weshowthathydrostaticparticularsforintermediateloadingconditionsofvariableshipgeometrycanbecalculatedbyusinganalyticalsolutionsofbasichydrostaticintegralsforarbitrarylistangles,andobtainedforpolynomialradialbasisfunctiondescriptionofshipgeometry.Thecalculationswillbeperformedforsymmetrichopperopeningduringcargodischargeprocedure,thuscoveringallSplitTSHDregularunloadingconditions,withoutexaminationofshiphullopeningfailuremodes.Thus,allshiphydrostaticpropertieswillbepre-calculatedanalyticallyandpreparedforfurtherstabilitycalculations,asopposedtotheusualnumericalcalculationsforinitialgeometryandevenkeelonly,ascurrentlyusedinnavalarchitecturedesign.

  • 标签: POLYNOMIAL radial basis function hydrostatic INTEGRALS
  • 简介:许多设计材料随紧张率的增加表明他们的压缩强度的动态改进,它在材料模型被包括了在影响和强风负担下面改进材料和结构的回答的数字模拟的可靠性。设计以hydrostatic-stress-sensitive方式表现的材料的一个范围的动态压缩强度上的紧张率效果被调查。hydrostatic-stress-sensitive材料的压缩强度的动态改进可以包括导致惯性的侧面的监禁效果,这被结束,作为一个non-strain-rate因素,它可以极大地提高这些材料的压缩强度。一些实验公式可以基于紧张率在这些hydrostatic-stress-sensitive材料的压缩强度上完成的动态压力紧张大小在预言上,并且这样过高估计结构的抵抗到影响和强风负担,导致保护的结构的非保守的设计。

  • 标签: 耐压强度 数字模拟 流体静力-压力感光材料 材料学
  • 简介:AbstractFor the detection of steatosis, quantitative ultrasound imaging techniques have achieved great progress in past years. Magnetic resonance imaging proton density fat fraction is currently the most accurate test to detect hepatic steatosis. Some blood biomarkers correlate with non-alcoholic steatohepatitis, but the accuracy is modest. Regarding liver fibrosis, liver stiffness measurement by transient elastography (TE) has high accuracy and is widely used across the world. Magnetic resonance elastography is marginally better than TE but is limited by its cost and availability. Several blood biomarkers of fibrosis have been used in clinical trials and hold promise for selecting patients for treatment and monitoring treatment response. This article reviews new developments in the non-invasive assessment of non-alcoholic fatty liver disease (NAFLD). Accumulating evidence suggests that various non-invasive tests can be used to diagnose NAFLD, assess its severity, and predict the prognosis. Further studies are needed to determine the role of the tests as monitoring tools. We cannot overemphasize the importance of context in selecting appropriate tests.

  • 标签: Fatty liver Non-alcoholic fatty liver disease Non-alcoholic steatohepatitis Liver fibrosis Cirrhosis Transient elastography FibroScan Magnetic resonance imaging
  • 简介:Thispaperinvestigatesthemathematicfeaturesofnon-linearmodelsanddiscussestheprocessingwayofnon-linearfactorswhichcontributestothenon-linearityofanonlinearmodel.Onthebasisoftheerrordefinition,thispaperputsforwardanewadjustmentcriterion,SGPE.Last,thispaperinvestigatesthesolutionofanon-linearregressionmodelinthenon-linearmodelspaceandmakesthecomparisonbetweentheestimatedvaluesinnon-linearmodelspaceandthoseinlinearmodelspace.

  • 标签: 非线性调节模型 测量误差 精确度 空间非线性模型
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  • 简介:Anumericalanalysisofnon-Newtonianfluidflowinnon-planararterywithbifurcationwasperformedbyusingafiniteelementmethodtosolvethethree-dimensionalNavier-Stokesequationscoupledwiththenon-Newtonianconstitutivemodels,includingCarreau,CrossandBinghammodels.Theobjectiveofthisstudyistoinvestigatetheeffectsofthenon-Newtonianpropertiesofbloodaswellascurvatureandout-of-planegeometryinthenon-planardaughtervesselsonthevelocitydistributionandwallshearstress.Theresultsofthisstudysupporttheviewthatthenon-planarityofbloodvesselsandthenon-Newtonianpropertiesofbloodareofimportantinhemodynamicsandplayasignificantroleinvascularbiologyandpathophysiology.

  • 标签: 非线性牛顿流体 血液动力学 颈动脉分流 数值分析 非平面动脉 病理生理学
  • 简介:Bacterialflagellarfilamentcanundergoastress-inducedpolymorphicphasetransitioninbothvitroandvivoenvironments.Thefilamenthas12differenthelicalforms(phases)characterizedbydifferentpitchlengthsandhelixradii.Whensubjectedtothefrictionalforceofflowingfluid,thefilamentchangesbetweenaleft-handednormalphaseandaright-handedsemi-coiledphaseviaphasenucleationandgrowth.Thispaperdevelopsnon-localfiniteelementmethod(FEM)tosimulatethephasetransitionunderad...

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  • 简介:SeveralextensionsofthelogicprogramminglanguagePrologtononHornclausesusecaseanalysistohandlenon-Hornclauses.Inthispaper,analyticalandempriricalevidencesarepresentedtoshowthat,bymakingasetofclausesless'non-Horn'usingpredicatedrenaming.theperformanceofthesecase-analysisbasedprocedurescanbeimprovedsignificantly.Inaddition,thepaperalsoinvestigatedtheproblemofefficeientlyconstructingapredicaterenamingthatreducesthedegreeof'non-Hornness'ofaclausesetmaximally.Itisshownthatthisproblemoffindingaredicaterenamingtoachieveminimal'non-Hornness'isNP-complete.

  • 标签: 人工智能 逻辑程序设计 NP-完备性
  • 简介:Akineticequationofnon-isothermalcrystamzationwasderivedbyextendingAvrami’sequationtothenon-isothermalsituation.Morecrystallizationinformationcanbeobtainedfromthiskineticequation.Thecurvesofnon-isothermalandisothermalcrystallizationswereanalysedandcomparedforpoly(ethyleneterephthalate)(PET),andtheresultswerediscussed.

  • 标签: NON-ISOTHERMAL CRYSTALLIZATION CRYSTALLIZATION KINETICS Poly (ethyene