学科分类
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71 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: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: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: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:Theprofilingmethodisthefirstmethodtoselectinmeasuringtheremotesensingreflectance.InthelightofthecharacteristicsofChina'scoastalwaters,wedevelopanewmethodtocompensatetheenvironment'seffectswiththedownwellingirradiance'sprofileandtoestimatetheunderwaterremote-sensingreflectancerrs(λ).Theresultindicatesthattherelativedeviationofrepetitiousrrs(λ)inonestationisaround10%.

  • 标签: 剖面勘探法 遥感反射率 环境效应 海下测量 光学性质
  • 简介:Identificationofmodalparametersofalinearstructurewithoutput-onlymeasurementshasreceivedmuchattentionoverthepastdecades.Inthepaper,theNaturalExcitationTechnique(NExT)isusedforacquisitionoftheimpulsesignalsfromthestructuralresponses.ThenEigensystemRealizationAlgorithm(ERA)isutilizedformodalidentification.(SAMFM),isdevelopedtodistinguishthetruemodesfromnoisemodes,andtoimprovetheprecisionoftheidentifiedmodalfrequenciesofthestructure.Anoffshoreplatformismodeledwiththefiniteelementmethod.Thetheoreticalmodalparametersareobtainedforacomparisonwiththeidentifiedvalues.ThedynamicresponsesoftheplatformunderrandomwaveloadingarecomputedforprovidingtheoutputsignalsusedforidentificationwithERA.Resultsofsimulationdemonstratethattheproposedmethodcandeterminethesystemmodalfrequencywithhighprecision.

  • 标签: 识别模型 统计法 海洋平台 特征系统实现算法 线性结构力学
  • 简介:Thefinitevolumemethod(FVM)hasmanyadvantagesin2-Dshallowwaternumericalsimulation.Inthisstudy,thefinitevolumemethodisusedwithunstructuredtriangulargridstosimulatethetidalcurrents.TheRoeschemeisappliedinthecalculationoftheintercellnumericalflux,andtheMUSCLmethodisintroducedtoimproveitsaccuracy.Thetimeintegralisatwo-stepschemeofforecastandrevision.Fortheverificationofthepresentmethod,theStoker'sproblemiscalculatedandtheresultiscomparedwiththemathematicallyanalyticsolutions.Thecomparisonindicatesthatthemethodisfeasible.Aseaareaofaportisusedasanexampletotestthemethodestablishedhere.Theresultshowsthatthepresentcomputationalmethodissatisfactory,anditcouldbeappliedtotheengineeringfields.

  • 标签: 潮流 三角网格 数值模型 有限体积法 海洋动力学
  • 简介:Theprofilemethodistheprincipalmethodfirsttobechosentomeasuretheapparentopticalparametersofwaters.Thispaperfirstintroducestheprofilemethodbriefly,thenmodifiestheappliedalgorithminthelightofthepropertiesoftheclass-Ⅱwatersandlastly,analysestheeffectofapplication.

  • 标签: 剖面法 海洋测量 光学参数 海洋水文学
  • 简介:Inthispaper,thecalculatingchartsandformulaeaboutwavepressureonthebreastwallarederivedwithsevenparametersonthebasisofphysicalmodelstudy.Theverificationshowsthatthechartsagreewiththeexample,andareadoptedintheSpecificationsofFisheryHarboursBreakwaterbytheMinistryofAgricultures.

  • 标签: BREAKWATER BREAST WALL WAVE pressure distribution
  • 简介:-Measuringmulti-directionalwaveswiththewavegaugearrayisoneofthefundamentalandeasilyrealisedmethods.Inthispaper,thewavegaugearrayisdescribedandtheeffectsofthegaugespacing,thearrayorientations,etc.ofthethreearrayarrangements,i.e.,lineararray,T-typearrayandpentagonarray,ontheresolutionofthedirectionalspreadingofwaves,areinvestigatedexperimentally.Thisstudycanbeusedasareferenceintheexperimentalstudyandthefieldmeasurementofdirectionalwaves.

  • 标签: multi-directional WAVES measurement method directional SPECTRUM
  • 简介:OnthebasisoftherandomamplifiedpolymorphicDNA-fingerprinting(RAPD)method,10morphospeciesofscuticociliatesfrom7genera,including15clonesof13strains,Uronemarnarinum,Uronemacfmarinum,Parauronernavirginianum,P.longurn,Metanophryssimilis,M.sinensis,Paralembusdigitiformis,Mesanophryscarcini,ParanophrysmagnaandCohnilembusverminuswereanalysedusing8oligonucleotideprimers.Thegeneticsimilarityamongtheclonesofthesamestrainmeasuredbyaband-sharingindexis0.97~0.98,while0.40~0.52amongstrains.Thisvaluemeasuredis0.39~0.46amongcongenersofthesamegenus,whereas0.16~0.47betweendifferentgenera.Adistancetreewasconstructedbasedon8-primeranalysis,inwhichthescuticociliatesinvestigatedwereseparatedintotwoclusters:oneconsistsof2genera,UronemaandParauronema,andtheotherwascomposedoffive,Metanophrys,Mesanophrys,Paranophrys,ParalembusandCohnilembus.ItisdemonstratedalsothatthemorphospeciesParauronemavirginianummaybeaspecies-complex,i.e.,itcontainsdifferentgenospecies.

  • 标签: RAPD 基因距离 纤毛孢子 随机放大形态识别 DNA指纹