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.
简介:Anewmethodofcodinganddecodinginthesystemofunderwaterimagetransmissionisintroduced,includingtherapiddigitalfrequencysynthesizerinmultiplefrequencyshiftkeying,imagedatagenerator,imagegrayscaledecoderwithintelligentfuzzyalgorithm,imagerestorationanddisplayonmicrocomputer.
简介:Inthispaper,severalmathmaticalmodelsforthepile-soilinteractionareoutlined.TheBoundaryElementMethodisoneoftheveryeffectivemethodsforthereasonablemodelsofelasticityandelastoplasticity.ThemajorofthispaperisconcernedwiththeBoundaryElementMethodforthepile-soilinteraction,includinggeneralmethodsandcalculatingformulationofstaticanddynamicanalysisofthepileandpilegroups.Someresultsofanalysisarealsogiven.
简介:Tounderstandthemooringenergyduringpositioning,theexpressionsoffouritemsconcerningmooringlineenergyarepresentedbasedonafiniteelementmodel,includinggravitationalandelasticpotentialenergy,kineticenergyanddissipatedenergyduetomooring-induceddamping.Inastaticcase,theforcecalculatedfromthederivativeofpotentialenergywithrespecttodistanceiscomparedwiththatofdirectcalculation.Theresultsarefoundfitwell,whichindicatesthelawofconservationofenergyandalsoshowsthecorrectnessofthepotentialenergyresults.Forthecasesofasinglemooringlinewiththeattachmentpointoscillatingwithdifferentamplitudesinhorizontalorverticaldirection(correspondingtosurgeandrollmotionsrespectively),andthecaseofthemooringlinewithahorizontalbichromaticoscillationontheattachmentpoint,thetimehistoryofthefirstthreeitemsarecalculatedandanalyzed,also,theindicatordiagramformooring-induceddampingaregiven.Theseresultsrevealtheenergystateofthemooringlineandcanprovideabetterunderstandingofhowthemooringlineworks.
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.
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.
简介:Inthispaper,anewbiasestimationmethodisproposedandappliedinaregionalensembleKalmanfilter(EnKF)basedontheWeatherResearchandForecasting(WRF)Model.Themethodisbasedonahomogeneouslinearbiasmodel,andthemodelbiasisestimatedusingstatisticsateachassimilationcycle,whichisdifferentfromthestateaugmentationmethodsproposedinpreviousliteratures.Thenewmethodprovidesagoodestimationforthemodelbiasofsomespecificvariables,suchassealevelpressure(SLP).AseriesofnumericalexperimentswithEnKFareperformedtoexaminethenewmethodunderasevereweathercondition.Resultsshowthepositiveeffectofthemethodontheforecastingofcirculationpatternandmeso-scalesystems,andthereductionofanalysiserrors.ThebackgrounderrorcovariancestructuresofsurfacevariablesandtheeffectsofmodelsystembiasonEnKFarealsostudiedundertheerrorcovariancestructuresandanewconcept‘correlationscale’isintroduced.However,thenewmethodneedsfurtherevaluationwithmorecasesofassimilation.
简介:Adesignmethodofreinforcedconcrete(R.C.)offshoreplatformswithnonlinearfiniteelementanalysisisproposed.Accordingtothemethod,acomputerprogramisdeveloped.Inthisprogramnonlinearconstitutiverelationshipsandstrengthcriteriaofconcreteandsteelbarsareincluded,andtheprogressivecrackingandcrushingoftheconcretearetakenintoaccount.Basedonthestressdistributionobtainedbythenonlinearfiniteelementanalysis,theamountofreinforcementinthecontrolsectionscanbecomputedandadjustedautomaticallybytheprogramtosatisfytherequirementofthedesign.Theamountofreinforcementrequiredinthecontrolsections,whichareobtainedwiththenonlinearfiniteelementanalysis,isagreeabletothatobtainedintheexperiment.ThisshowsthatthedesignmethodofR.C.offshoreplatformwiththenonlinearfiniteelementmethodproposedbytheauthorsisreliableforpracticaluse.
简介:AnewmethodofNeutronActivationAnalysis(NAA)forsedimentmovementstudyispresentedinthispaper.Throughanalyzingthenaturalsediment,theinformationaboutnaturaltracingagentshasbeenobtained,whichcanshowthedirectionofsedimentmovementandrelativedischargeofsedimenttransportation.Testresultsinsomeareas,suchasShantouHarbourandHangzhouBay,areingoodagreementwiththosefromnormalhydrologicmeasurementsandsomeresultsarenotobtainablewiththelatter.TheNAAiseconomical,practicalandreliable,andshouldbewidelyusedinengineeringpractice.
简介:Throughnumericalmodeling,akindofsimplifiedcalculatingmethodforstandingwavepressureonverticalfacebreakwaterhavebeenputforward.Notonlytheformulasproposedinthispaperaresimpleinformandveryeasyinuse,butalsotheypossesscontinuityonthefullrangeofstandingwave.Andmore,theprecisionrequiremenntsofcalculationcanbesatisfiedtoacertainextentinengineeringpractice.
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??
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.
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。
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.