学科分类
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182 个结果
  • 简介:Theseaicecoverdisplaysvariousdynamicalcharacteristicssuchasbreakup,rafting,andridgingunderexternalforces.Tomodeltheicedynamicprocessaccurately,theeffectivenumericalmodelingmethodshouldbeestablished.Inthispaper,amodifiedparticle-in-cell(PIC)methodforseaicedynamicsisdevelopedcouplingthefinitedifference(FD)methodandsmoothedparticlehydrodynamics(SPH).Inthismethod,theicecoverisfirstdiscretizedintoaseriesofLagrangianiceparticleswhichhavetheirownsizes,thicknesses,concentrationsandvelocities.TheicethicknessandconcentrationatEuleriangridpositionsareobtainedbyinterpolationwiththeGaussianfunctionfromtheirsurroundingiceparticles.ThemomentumoficecoverissolvedwithFDapproachtoobtaintheEuleriancellvelocity,whichisusedtoestimatetheiceparticlevelocitywiththeGaussianfunctionalso.Thethicknessandconcentrationoficeparticlesareadjustedwithparticlemassdensityandsmoothlength,whichareadjustedwiththeredistributionoficeparticles.WiththeabovemodifiedPICmethod,numericalsimulationsforicemotioninanidealizedrectangularbasinandtheicedynamicsintheBohaiSeaarecarriedout.ThesesimulationsshowthatthismodifiedPICmethodisapplicabletoseaicedynamicssimulation.

  • 标签: 海冰 动力学分析 PIC 数值模拟 FD
  • 简介:Anewmethodofcodinganddecodinginthesystemofunderwaterimagetransmissionisintroduced,includingtherapiddigitalfrequencysynthesizerinmultiplefrequencyshiftkeying,imagedatagenerator,imagegrayscaledecoderwithintelligentfuzzyalgorithm,imagerestorationanddisplayonmicrocomputer.

  • 标签: UNDERWATER IMAGE transmission digital FREQUENCY synthesizer
  • 简介:高光谱影像包含有丰富的地物类别信息,但由于受分类方法等因素的限制,这些信息并不能得到充分的挖掘.组合分类器由于可以实现各分类结果信息的互补,因而总有着较各单分类器效果更好的分类性能.将组合分类方法引入到高光谱影像的分类实践,并对组合的关键问题一组合规则进行探讨,提出了混合组合规则的概念.实验表明,利用该组合分类方法对高光谱影像进行分类,可以得到良好的处理结果.

  • 标签: 高光谱 分类 分类器 组合
  • 简介:Inthispaper,severalmathmaticalmodelsforthepile-soilinteractionareoutlined.TheBoundaryElementMethodisoneoftheveryeffectivemethodsforthereasonablemodelsofelasticityandelastoplasticity.ThemajorofthispaperisconcernedwiththeBoundaryElementMethodforthepile-soilinteraction,includinggeneralmethodsandcalculatingformulationofstaticanddynamicanalysisofthepileandpilegroups.Someresultsofanalysisarealsogiven.

  • 标签: PILE soil PILE-SOIL interaction BOUNDARY ELEMENT
  • 简介:Tounderstandthemooringenergyduringpositioning,theexpressionsoffouritemsconcerningmooringlineenergyarepresentedbasedonafiniteelementmodel,includinggravitationalandelasticpotentialenergy,kineticenergyanddissipatedenergyduetomooring-induceddamping.Inastaticcase,theforcecalculatedfromthederivativeofpotentialenergywithrespecttodistanceiscomparedwiththatofdirectcalculation.Theresultsarefoundfitwell,whichindicatesthelawofconservationofenergyandalsoshowsthecorrectnessofthepotentialenergyresults.Forthecasesofasinglemooringlinewiththeattachmentpointoscillatingwithdifferentamplitudesinhorizontalorverticaldirection(correspondingtosurgeandrollmotionsrespectively),andthecaseofthemooringlinewithahorizontalbichromaticoscillationontheattachmentpoint,thetimehistoryofthefirstthreeitemsarecalculatedandanalyzed,also,theindicatordiagramformooring-induceddampingaregiven.Theseresultsrevealtheenergystateofthemooringlineandcanprovideabetterunderstandingofhowthemooringlineworks.

  • 标签: 单点系泊 有限元法 能源 应用 潜在能量 能量守恒定律
  • 简介:这篇论文论述一个新算法由改变形式的参数在结构预言损坏的地点和严厉。损坏察觉的一个存在算法被考察,新算法被提出改进损坏由在存在算法消除乖僻的假设和限制定位和严厉评价的精确性。当适用于为哪个预先损坏的two-dimensionalframe结构时,损坏预言精确性数字地为每个算法被估计,损坏以后的形式的参数为仅仅颤动的一些模式是可得到的。当时,分析结果说明新算法的改进精确性与存在算法相比。

  • 标签: 非破坏性检测 损伤识别 模型参数 结构损伤 海洋工程
  • 简介:一个二维的数字模型被建议在江苏省从一个发电厂模仿热分泌物。在模型的方程在于oftwo维的非稳定的浅水区方程和热废物搬运方程。Finitevolume方法(FVM)习惯于discretize切开的浅水区方程,和流动差别(FDS)计划被使用。有一样的温度增长的计算区域在海水上显示出热分泌物的效果。在模仿的结果和试验性的数据hows之间的比较好同意。它显示这个方法能在沿海的区域在热传递模拟给高精确。

  • 标签: 数值模拟 热量 有限体积法 潮汐 海岸
  • 简介:Noroviruses(NoVs)arewidespreadcausesofnonbacterialgastroenteritis.OutbreaksofNoVscauseddiseasesarecommonlyascribedtotheconsumptionofcontaminatedshellfish.TheconcentrationandRNAextractionofNoVsarecrucialstepsofdetectingNoVsinshellfish.Thisstudyaimedtoselectasimple,rapidandhighlyefficientrecoverymethodofNoVsdetectionwithreal-timeRT-PCR.FourmethodsofrecoveringGI.3andGII.4NoVsfromspikeddigestivetissuesofoystersandclams,respectively,werecompared,ofthem,themethodinvolvingproteinaseKandPEG8000wasfoundthemostefficient.Withthismethod,9.3%and13.1%ofGI.3andGII.4NoVswererecoveredfromoystersand9.6%and12.3%ofGI.3andGII.4NoVswererecoveredfromclams,respectively.ThismethodwasfurtherusedtodetectNoVsin84oysters(Crassostreagigas)and86clams(Ruditapesphilippinarum)collectedfrom10coastalcitiesinChinafromJan.2011toFeb.2012.TheNoVsisolationrateswere10.47%ofclams(9/86)and7.14%ofoysters(6/84).AllthedetectedNoVsbelongedtogenotypeGII.TheNoVsrecoverymethodselectedisefficientforNoVsdetectioninoystersandclams.

  • 标签: 诺沃克病毒 牡蛎 RT-PCR检测 蛤蜊 恢复方法 RNA提取
  • 简介:Anovelefficienttrackinitiationmethodisproposedfortheharshunderwatertargettrackingenvironment(heavyclutterandlargemeasurementerrors):tracksplitting,evaluating,pruningandmergingmethod(TSEPM).Trackinitiationdemandsthatthemethodshoulddeterminetheexistenceandinitialstateofatargetquicklyandcorrectly.Heavyclutterandlargemeasurementerrorscertainlyposeadditionaldifficultiesandchallenges,whichdeteriorateandcomplicatethetrackinitiationintheharshunderwatertargettrackingenvironment.Therearethreeprimaryshortcomingsforthecurrenttrackinitiationmethodstoinitializeatarget:(a)theycannoteliminatetheturbulencesofcluttereffectively;(b)theremaybeahighfalsealarmprobabilityandlowdetectionprobabilityofatrack;(c)theycannotestimatetheinitialstateforanewconfirmedtrackcorrectly.Basedonthemultiplehypothesestrackingprincipleandmodifiedlogic-basedtrackinitiationmethod,inordertoincreasethedetectionprobabilityofatrack,tracksplittingcreatesalargenumberoftrackswhichincludethetruetrackoriginatedfromthetarget.Andinordertodecreasethefalsealarmprobability,basedontheevaluationmechanism,trackpruningandtrackmergingareproposedtoreducethefalsetracks.TSEPMmethodcandealwiththetrackinitiationproblemsderivedfromheavyclutterandlargemeasurementerrors,determinethetarget’sexistenceandestimateitsinitialstatewiththeleastsquaresmethod.What'smore,ourmethodisfullyautomaticanddoesnotrequireanykindmanualinputforinitializingandtuninganyparameter.Simulationresultsindicatethatournewmethodimprovessignificantlytheperformanceofthetrackinitiationintheharshunderwatertargettrackingenvironment.

  • 标签: TRACK initiation TRACK splitting TRACK evaluating
  • 简介:Inthispaper,anewbiasestimationmethodisproposedandappliedinaregionalensembleKalmanfilter(EnKF)basedontheWeatherResearchandForecasting(WRF)Model.Themethodisbasedonahomogeneouslinearbiasmodel,andthemodelbiasisestimatedusingstatisticsateachassimilationcycle,whichisdifferentfromthestateaugmentationmethodsproposedinpreviousliteratures.Thenewmethodprovidesagoodestimationforthemodelbiasofsomespecificvariables,suchassealevelpressure(SLP).AseriesofnumericalexperimentswithEnKFareperformedtoexaminethenewmethodunderasevereweathercondition.Resultsshowthepositiveeffectofthemethodontheforecastingofcirculationpatternandmeso-scalesystems,andthereductionofanalysiserrors.ThebackgrounderrorcovariancestructuresofsurfacevariablesandtheeffectsofmodelsystembiasonEnKFarealsostudiedundertheerrorcovariancestructuresandanewconcept‘correlationscale’isintroduced.However,thenewmethodneedsfurtherevaluationwithmorecasesofassimilation.

  • 标签: 中尺度系统 资料同化 估计方法 齐次线性 卡尔曼滤波 统计模型
  • 简介:Adesignmethodofreinforcedconcrete(R.C.)offshoreplatformswithnonlinearfiniteelementanalysisisproposed.Accordingtothemethod,acomputerprogramisdeveloped.Inthisprogramnonlinearconstitutiverelationshipsandstrengthcriteriaofconcreteandsteelbarsareincluded,andtheprogressivecrackingandcrushingoftheconcretearetakenintoaccount.Basedonthestressdistributionobtainedbythenonlinearfiniteelementanalysis,theamountofreinforcementinthecontrolsectionscanbecomputedandadjustedautomaticallybytheprogramtosatisfytherequirementofthedesign.Theamountofreinforcementrequiredinthecontrolsections,whichareobtainedwiththenonlinearfiniteelementanalysis,isagreeabletothatobtainedintheexperiment.ThisshowsthatthedesignmethodofR.C.offshoreplatformwiththenonlinearfiniteelementmethodproposedbytheauthorsisreliableforpracticaluse.

  • 标签: finite element method reinforced concrete OFFSHORE
  • 简介:AnewmethodofNeutronActivationAnalysis(NAA)forsedimentmovementstudyispresentedinthispaper.Throughanalyzingthenaturalsediment,theinformationaboutnaturaltracingagentshasbeenobtained,whichcanshowthedirectionofsedimentmovementandrelativedischargeofsedimenttransportation.Testresultsinsomeareas,suchasShantouHarbourandHangzhouBay,areingoodagreementwiththosefromnormalhydrologicmeasurementsandsomeresultsarenotobtainablewiththelatter.TheNAAiseconomical,practicalandreliable,andshouldbewidelyusedinengineeringpractice.

  • 标签: : TRACING method NATURAL SEDIMENT NEUTRON
  • 简介:Throughnumericalmodeling,akindofsimplifiedcalculatingmethodforstandingwavepressureonverticalfacebreakwaterhavebeenputforward.Notonlytheformulasproposedinthispaperaresimpleinformandveryeasyinuse,butalsotheypossesscontinuityonthefullrangeofstandingwave.Andmore,theprecisionrequiremenntsofcalculationcanbesatisfiedtoacertainextentinengineeringpractice.

  • 标签: clapotics vertical BREAKWATER WAVE HEIGHT WAVE
  • 简介:帮助的酸水解作用被建立准备-carra-oligosaccharides的微波的一个快速的方法。最佳的水解作用条件被直角的测试决定。oligosaccharides的聚合(DP)的度被高效检测薄层层析(HPTLC)和polyacrylamide胶化电气泳动(页)。就HPTLC和页的结果而言,微波的最佳条件帮助了酸水解作用被决定。-carrageenan的集中是5mgmL<啜class=“a-plus-plus”>1;反应答案被适应pH3与冲淡盐酸酸;答案为在这些indic燬?燬的15个变化是在在100点的微波照耀下面的hydrolyzed吗??

  • 标签: 酸水解法 微波辅助 寡糖 制备 聚丙烯酰胺凝胶电泳 HPTLC
  • 简介:Factoranalysisisusedtostudytheorganiccompoundsthathavehighdegreeofcorrelationwithbiomassinalgalblooming.Basedonthiscorrelation,theyarenamedcharacteristicorganiccompounds.Thecompoundsfoundaresequalene(SQU),cedrol(CED),2,5-cyclohexadiene-1,4-dione,2,6-bis(1,1-dimthylethyl)(PBQ),phenol,2,6-bis(1,1-dimethylethy-4-methyl)(BHT),3-t-butyl-4-hydroxyanisole(BHA),1,2-benzenedicarboxylieacid,bis-(2-methylpropyl)ester(DIBP),dibutylphthalate(DNBP),respectively.Monitoringthevariationsofconcentrationofthesecharacteristicorganiccompoundsinseawatermayprovidescientificbasisforstudyingandforecastingredtides.

  • 标签: 有机化合物 海藻 雪松醇 赤潮
  • 简介:为受到动人的负担的桥的一个新定位损坏的方法被介绍,并且一新“动人的负担定位损坏的指示物”(MLDI)被介绍。车辆作为动人的负担被建模,桥作为一根Euler-Bernoulli横梁被简化,并且损坏被元素的僵硬性质的减小模仿。在基线模型(undamaged)和损坏模型的每个节点的弯曲和MLDI价值分别地被计算。然后,损坏或损坏能从MLDI价值的一个突然的变化被定位。建议方法的可行性和有效性被数字模拟验证。结果显示方法是有效的,是有能力的不仅精确地定位单个损坏,而且在简单地支持的桥定位多重损坏,包括在连续的桥的多重损坏。结果也显示MLDI罐头精确地在5%测量噪音下面定位损坏。

  • 标签: 桥梁 移动载荷 损坏 定位方法 曲率
  • 简介:TosolvethenumericaldivergenceproblemofthedirecttimedomainGreenfunctionmethodforthemotionsimulationoffloatingbodieswithlargeflare,atimedomainhybridRankine-Greenboundaryelementmethodisproposed.Inthisnumericalmethod,thefluiddomainisdecomposedbyanimaginarycontrolsurface,atwhichthecontinuousconditionshouldbesatisfied.ThentheRankineGreenfunctionisadoptedintheinnerdomain.ThetransientfreesurfaceGreenfunctionisappliedintheouterdomain,whichisusedtofindtherelationshipbetweenthevelocitypotentialanditsnormalderivativefortheinnerdomain.Besides,thevelocitypotentialatthemeanfreesurfacebetweenbodysurfaceandcontrolsurfaceisdirectlysolvedbytheintegrationscheme.Thewaveexcitingforceiscomputedthroughtheconvolutionintegrationwithwaveelevation,byintroducingtheimpulseresponsefunction.Additionally,thenonlinearFroude-Krylovforceandhydrostaticforce,whichiscomputedundertheinstantaneousincidentwavefreesurface,aretakenintoaccountbythedirectpressureintegrationscheme.Thecorrespondingnumericalcomputercodeisdevelopedandfirstusedtocomputethehydrodynamiccoefficientsofthehemisphere,aswellasthetimehistoryofashipwithlargeflare;goodagreementisobtainedwiththeanalyticalsolutionsaswellastheavailablenumericalresults.ThenthehydrodynamicpropertiesofaFPSOarestudied.Thehydrodynamiccoefficientsagreewellwiththeresultscomputedbythefrequencymethod;theinfluenceofthetimeintervalandthetruncatedtimeisinvestigatedindetail.

  • 标签: rankine-green method NONLINEAR WAVE FORCE IMPULSE