简介：Ananalyticalstudyofthetwodegreesoffreedomnonlineardynamicalsystemispresented.Theinternalmotionofthesystemisseparatedanddescribedbyonefourthorderdifferentialequation.AnapproximateapproachallowsreducingtheproblemtotheDuffingequationwithadequateinitialconditions.Anovelideaforaneffectivestudyofnonlineardynamicalsystemsconsistinginaconceptofthesocalledlimitingphasetrajectoriesisapplied.Bothqualitativeandquantitativecomplexanalyseshavebeenperformed.Importantnonlineardynamicaltransitiontypephenomenaaredetectedanddiscussed.Inparticular,nonsteadyforcedsystemvibrationsareinvestigatedanalytically.

简介：Responsespectralmomentsareusefulforsystemreliabilityanalysis.Usually,spectralmo-mentsarecalculatedbythefrequencydomainmethod.Basedonthetimedomainmodalanalysisofrandomvibrations,theauthorspresentanewmethodforcalculatingresponsespectralmomentsthroughresponsecorrelationfunctions.Themethodcanbeappliedtobothclassicalandnon-classicaldampingcasesandtothreekindsofrandomexcitations,i.e.,whitenoise,band-limitedwhitenoise,andfilteredwhitenoise.

简介：AfastadaptivesymplecticalgorithmnamedMultiresolutionSymplecticScheme(MSS)wasfirstpresentedtosolvetheproblemofthewavepropagation(WP)incomplexmedia,usingthesymplecticschemeandDaubechies'compactlysupportedorthogonalwavelettransformtorespectivelydiscretisethetimeandspacedimensionofwaveequation.TheproblemwassolvedinmultiresolutionsymplecticgeometryspaceundertheconservativeHamiltoniansystemratherthanthetraditionalLagrangesystem.Duetothefascinatingpropertiesofthewaveletsandsymplecticscheme,MSSisapromisingmethodbecauseoflittlecomputationalburden,robustnessandrealityoflong-timesimulation.

简介：ResearcheffortsmadesofartosimulatefibresuspensionflowsarelimitedtofibresuspensionsinNewtonianfluids.Thoughshortfibrecompositesaremostlymadeofpolymers,lackofsuitableconstitutiveequationsforfibresuspensionsinviscoelasticfluidsfrustratesattemptstosimulateflowsofthesesuspensions.ApreliminaryworkdonebytheauthorledtoaconstitutiveequationforsemiconcentratedfibresuspensionsintheOldroyd-Bfluid.Thispaperdescribesthemathematicalformulationoftheflowproblemsforsuchasuspensionandthenumericalproceduretosolvethem.Somenumericalresultsofflowpastasphereinatubearealsopresented.

简介：Multi-scalestructuresinvolvedinemulsionandmicrospherecomplexsystemsarepresentedanddiscussed.Thestabilityandspatio-temporalstructuresofemulsions,aswellasnano-structuresformedonthesurfaceofmicrospheresafterpolymerization,areaffectedbythemolecularemulsifier/stabilizerstructuresandtheadsorbedemulsifier/stabilizernano-structuresontheoil/waterinterface.Thebroadsizedistributionandvariationofsurfacefeaturesofdropletsareresponsibleforvariationsoftheadsorbedemulsifier/stabilizerstructuresandthestabilityoftheemulsions.Ontheotherhand,preparationofauniformlysizedemulsionandemploymentofacombinedemulsifier/stabilizersystemcanpreservethestabilityoftheemulsionsandmicrospheres.Theabovephenomenashouldbemodeledbyamultiscalemethod,inordertomaintainthestabilityofindividualemulsionsystemsandrealizethedesirednano-structuresofmicrospheresbychoosingadequateemulsifier/stabilizerandexperimentalparameters.

简介：ComplexmodesandtravelingwavesinaxiallymovingTimoshenkobeamsarestudied.Duetotheaxiallymovingvelocity,complexmodesemergeinsteadofrealvaluemodes.Correspondingly,travelingwavesarepresentfortheaxiallymovingmaterialwhilestandingwavesdominateinthetraditionalstaticstructures.Theanalyticalresultsobtainedinthisstudyareverifiedwithanumericaldifferentialquadraturemethod.

简介：这篇评论文章在基于分子的流动的一个新组的发展报导最近的进步诊断技术，包括分子的标注velocimetry(音乐电视)和分子的标注计温(MTT)，为热地导致的流动结构的两质的流动可视化和流动速度和温度分布的量的整个地的大小。音乐电视和MTT技术能容易也被联合导致所谓的分子的标注velocimetry和计温(MTV&T)技术，它是在液体流动完成流动速度和温度分发的同时的大小的capble。而不是使用微小的粒子，分子的标注技术(音乐电视，MTT，和MTV&T)使用发磷光的分子，它能被适当波长的光子在刺激之上变成长持续的发光标记，作为为流动速度和温度大小的tracers。分子的标注技术的唯一的吸引力和实现被三个申请例子表明，它包括：(1)确定从激烈的柱体的不稳定的热转移过程到包围液体流动以便在在混合并且强迫的热传送对流政体操作的激烈的柱体后面在wake不稳定性上检验热效果，(2)处理揭示变化的不稳定的热转移和阶段的时间进化在内微尺寸，糖衣水微滴以便阐明对飞机糖衣现象恰当的内在的物理，并且(3)完成同时的微滴尺寸，v

简介：Inremotesensingorlasercommunicationspacemissions,spacecraftneedfastmaneuverandfaststabilizationinordertoaccomplishagileimagingandattitudetrackingtasks.However,fastattitudemaneuverscaneasilycauseelasticdeformationsandvibrationsinflexibleappendagesofthespacecraft.Thispaperfocusesonthisproblemanddealswiththecombinedcontroloffastattitudemaneuverandstabilizationforlargecomplexspacecraft.Themathematicalmodelofcomplexspacecraftwithflexibleappendagesandmomentumbiasactuatorsonboardispresented.Basedontheplantmodelandcombinedwiththefeedbackcontroller,modalparametersoftheclosed-loopsystemarecalculated,andamultiplemodeinputshaperutilizingthemodalinformationisdesignedtosuppressvibrations.Aimingatreducingvibrationsexcitedbyattitudemaneuver,aquinticpolynomialformrotationpathplanningisproposedwithconstraintsontheactuatorsandtheangularvelocitytakenintoaccount.Attitudemaneuversimulationresultsofthecontrolsystemswithinputshaperorpathplanninginloopareseparatelyanalyzed,andbasedontheanalysis,acombinedcontrolstrategyispresentedwithbothpathplanningandinputshaperinloop.Simulationresultsshowthatthecombinedcontrolstrategysatisfiesthecomplexspacecraft’srequirementoffastmaneuverandstabilizationwiththeactuators’torquelimitationsatisfiedatthesametime.

简介：BackgroundInresponsetotheevolutionofscienceandtechnologyfromcompartmentalizationtoreunification,thestudyofcomplexsystemsandmulti-scalemethodologyhasreceivedincreasingattentionfromvariousscientificdisciplinesandengineeringfields,somuchsothatcomplexityhassometimesbeencalledthescienceofthe21stcenturywithmulti-scalemethodologyasanaccompanyingchallenge.

简介：Themulti-scalestructuresofcomplexflowsinchemicalengineeringhavebeengreatchallengestothedesignandscalingofsuchsystems,andmulti-scalemodelingisthenaturalwayinresponse.Particlemethods(PMs)areidealconstituentsandpowerfultoolsofmulti-scalemodels,owingtotheirphysicalfidelityandcomputationalsimplicity.Especially,pseudo-particlemodeling(PPM,Ge&Li,1996;Ge&Li,2003)ismostsuitableformolecularscaleflowpredictionandexplorationoftheoriginofmulti-scalestructures;macro-scalePPM(MaPPM,Ge&Li,2001)andsimilarmodelsareadvantageousformeso-scalesimulationsofflowswithcomplexanddynamicdiscontinuity,whilethelatticeBoltzmannmodelismorecompetentforhomogeneousmediaincomplexgeometries;andmeso-scalemethodssuchasdissipativeparticledynamicsareuniquetoolsforcomplexfluidsofuncertainpropertiesorflowswithstrongthermalfluctuations.Allthesemethodsarefavorableforseamlessinterconnectionofmodelsfordifferentscales.However,asPMsarenotoriginallydesignedaseithertoolsforcomplexityorconstituentsofmulti-scalemodels,furtherimprovementsareexpected.PPMisproposedformicroscopicsimulationofparticle-fluidsystemsasacombinationofmoleculardynamics(MD)anddirectsimulationMonte-Carlo(DSMC).ThecollisiondynamicsinPPMisidenticaltothatofhard-sphereMD,sothatmass,momentumandenergyareconservedtomachineaccuracy.However,thecollisiondetectionprocedure,whichismosttime-consuminganddifficulttobeparallelizedforhard-sphereMD,hasbeengreatlysimplifiedtoaprocedureidenticaltothatofsoft-sphereMD.Actually,thephysicalmodelbehindsuchatreatmentisessentiallydifferentfromMDandismoresimilartoDSMC,butanintrinsicdifferenceisthatinDSMCthecollisionsfollowdesignedstatisticalrulesthatarereflectionoftherealphysicalprocessesonlyinverylimitedcasessuchasdilutegas.PPMisidealforexploringthemechanismofcomplexflowsa

简介：Fordetailedstudyofcomplexchemicalreactionsmechanismsexperimentisconductedforselectedprivatereactions.Thiscausesaproblemofkineticparametersgetting-thesamesetofrateconstantsmustdescribebothpublicandprivatereactionstages,andalsoageneralmechanism.Inthispaper,solutionofthisproblemforareactionofolefinshydroaluminationisproposed.Tooptimizethecomputationalprocessamethodologyofparallelizationiselaborated.Onthebaseofparallelcomputations,akineticmodelforthereactionassignedisconstructed,andonitsbase,thephysicalandchemicalconclusionsaboutreactionmechanismaredone.

简介：Thispaperisconcernedwiththemodelingofrandomnessinmultiscaleanalysisofheterogeneousmaterials.Morespecifically,aframeworkdedicatedtothestochasticmodelingofrandompropertiesisfirstintroduced.Aprobabilisticmodelformatrix-valuedsecond-orderrandomfieldswithsymmetrypropertries,recentlyproposedintheliterature,isfurtherreviewed.AlgorithmsadaptedtotheMonteCarlosimulationoftheproposedrepresentationarealsoprovided.Thederivationsandcalibrationprocedurearefinallyexemplifiedthroughthemodelingoftheapparentpropertiesassociatedwithanelasticporousmicrostructurecontainingstochasticinterphases.

简介：Onthebasisofanisotropicmathematicalelasticity,usingmultipleconformalrepresentations,thestressfunctionsofmultiplecomplexvariablesforaninfinitemultiply-connectedanisotropicplatearede-rived.ThefunctionsaredevelopedinFourierseriesonunitcircles,andtheunknowncoefficientsofthefunctionsaredeterminedbyundeterminedcoefficientsmethod.Thenthestressesintheplatecanbecalcu-lated.Aplatecontainingmultipleellipticalholesorcracksisdiscussed,andthecorrespondingFORTRAN77programisdeveloped.Fiveexamplesaregiven.Theresultsshowthatthismethodisveryeffectiveandconvenient.

简介：Acompositebeamissymmetricifboththematerialpropertyandsupportaresymmetricwithrespecttothemiddlepoint.Inordertostudythefreevibrationperformanceofthesymmetriccompositebeamswithdifferentcomplexnonsmooth/discontinuousinterfaces,wedevelopanR(x)-orthonormaltheory,whereR(x)isanintegrableflexuralrigidityfunction.TheR(x)-orthonormalbasesinthelinearspaceofboundaryfunctionsareconstructed,ofwhichthesecond-orderderivativesoftheboundaryfunctionsareaskedtobeorthonormalwithrespecttotheweightfunctionR(x).WhenthevibrationmodesofthesymmetriccompositebeamareexpressedintermsoftheR(x)-orthonormalbaseswecanderiveaneigenvalueproblemendowedwithaspecialstructureofthecoefficientmatrixA:=[aij],aij=0ifi+jisodd.Basedonthespecialstructurewecanprovetwonewtheorems,whichindicatethatthecharacteristicequationofAcanbedecomposedintotheproductofthecharacteristicequationsoftwosub-matriceswithdimensionshalflower.Hence,wecansequentiallysolvethenaturalfrequenciesinclosed-formowingtothespecialtyofA.Weusethispowerfulnewtheorytoanalyzethefreevibrationperformanceandthevibrationmodesofsymmetriccompositebeamswiththreedifferentinterfaces.

简介：Inthepresentpaper,thecompatibilityequationfortheplanestressproblemsofpower-lawmaterialsistransformedintoabiharmonicequationbyintroducingtheso-calledcomplexpseudo-stressfunction,whichmakesitpossibletosolvetheelastic-plasticplanestressproblemsofstrainhardeningmaterialsdescribedbypower-lawusingthecomplexvariablefunctionmethodlikethatinthelinearelasticitytheory.Byusingthisgeneralmethod,theclose-formedanalyticalsolutionsforthestress,strainanddisplacementcomponentsoftheplanestressproblems’ofpower-lawmaterialsisdeducedinthepaper,whichcanalsobeusedtosolvetheelasto-plasticplanestressproblemsofstrain-hardeningmaterialsotherthanthatdescribedbypower-law.Asanexample,theproblemofapower-lawmaterialinfiniteplatecontainingacircularholeunderuniaxialtensionissolvedbyusingthismethod,theresultsofwhicharecomparedwiththoseofaknownasymptoticanalyticalsolutionobtainedbytheperturbationmethod.