简介：Whethertheconceptofeffectivestressandstraininelastic-plastictheoryisstillvalidundertheconditionoffinitedeformationwasmainlydiscussed.Theuni-axialcompressionexperimentsinplanestressandplanestrainstateswerechosenforstudy.Inthetwokindsofstressstates,thestress-straincurvedescribedbylogarithmstrainandrotatedKirchhoffstressmatchestheexperimentsdatabetterthanthecurvesdefinedbyotherstressstraindescription.

简介：Twodimensionalequationsofsteadymotionforthirdorderfluidsareexpressedinaspecialcoordinatesystemgeneratedbythepotentialflowcorrespondingtoaninviscidfluid.Fortheinviscidflowaroundanarbitraryobject,thestreamlinesarethephicoordinatesandvelocitypotentiallinesarepsi-coordinateswhichformanorthogonalcurvilinearsetofcoordinates.Theoutcome,boundarylayerequations,isthenshowntobeindependentofthebodyshapeimmersedintotheflow.Asafirstapproximation,assumptionthatsecondgradetermsarenegligiblecomparedtoviscousandthirdgradeterms.Secondgradetermsspoilscalingtransformationwhichisonlytransformationleadingtosimilaritysolutionsforthirdgradefluid.ByusingLiegroupmethods,infinitesimalgeneratorsofboundarylayerequationsarecalculated.Theequationsaretransformedintoanordinarydifferentialsystem.NumericalsolutionsofoutcomingnonlineardifferentialequationsarefoundbyusingcombinationofaRunge-Kuttaalgorithmandshootingtechnique.

简介：Thestructuraldynamicsproblems,suchasstructuraldesign,parameteridentificationandmodelcorrection,areconsideredasakindoftheinversegeneralizedeigenvalueproblemsmathematically.Theinverseeigenvalueproblemsarenonlinear.Ingeneral,theycouldbetransformedintononlinearequationstosolve.Thestructuraldynamicsinverseproblemsweretreatedasquasimultiplicativeinverseeigenalueproblemswhichweresolvedbyhomotopymethodfornonlinearequations.Thismethodhadnorequirementsforinitialvalueessentiallybecauseofthehomotopypathtosolution.Numericalexampleswerepresentedtoillustratethehomotopymethod.

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

简介：Fromsuchactualconditionsastheeffectsofcharacteristicsofmiltilayerpetroleumgeologyandpermeationfluidmechanics,anewnumericalmodelisputforwardandcouplingsplitting-upimplicitinteractiveschemeisformed.FortheactualsituationofDongyinghollow(four-layer)andTanhairegion(three-layer)ofShengliPetroleumField,thenumericalsimulationtestresultsandtheactualconditionsarecoincident.

简介：Adirectnumericalsimulationisperformedon2563gridsfordecayingisotropicturbulence.Thetotalkinematicenergy,Taylormicro-scale,Taylormicro-scaleReynoldsnumberandthevelocityderivativeskewnessarecalculated.Thesnapshotsofenergyspectraandenergytransferspectraareplotted.ThesemeasurementsverifytheDIApredictions:decayingisotropicturbulencehastheenergypropagationandoccupiesthefinaldecayperiods.Theskewnessremainstosomelevelwithsmallvariationeveninthefinaldecayperiod.

简介：Inthispaper,wecarryoutananalysisofthestructuralpropertiesofthesolutionstothespeedgradient(SG)trafficflowmodel.Undertheconditionthattherelaxationeffectcanbeneglected,itisshownthata1-shockora1-rarefactionisassociatedwiththefirstcharacteristic,butontheotherhand,acontactdiscontinuityratherthana2-shockora2-rarefactionisassociatedwiththesecondcharacteristic.Sincetheexistenceofa2-shockor2-rarefactionviolatesthephysicalmechanismofthetrafficflow,theSGmodelismorereasonable.Iftherelaxationeffectcannotbeneglected,itissomewhatdifficulttocarryouttheanalyticalanalysisandthenumericalsimulationresultsshouldbeobtained.

简介：Inordertoinvestigatetheinfluenceoftheverticalvibrationloadingontheliquefactionofsaturatedsand,onedimensionalmodelforthesaturatedsandwithaverticalvibrationispresentedbasedonthetwophasecontinuousmediatheory.Thedevelopmentoftheliquefactionandtheliquefactionregionareanalyzed.Itisshownthattheverticalvibrationloadingcouldinduceliquefaction.Therateoftheliquefactionincreaseswiththeincreaseoftheinitiallimitstrainorinitialporosityoramplitudeandfrequencyofloading,andincreaseswiththedecreaseofthepermeabilityorinitialmodulus.Itisshownalsothatthereisaphaselaginthesandcolumn.Whenthesandpermeabilitydistributionisnon-uniform,theporepressureandthestrainwillrisesharplywherethepermeabilityisthesmallest,andfracturemightbeinduced.Withthedevelopmentofliquefaction,thestrengthofthesoilfoundationbecomessmallerandsmaller.Inthelimitingcase,landslidesordebrisflowscouldoccur.

简介：AnFEanalysisprocedurewaspresentedtopredictthebehaviorofsoilogeogridinterctionunderautomobileloading.Thedynamicinteractionsbetweenthetransversebars,thelongitudinalribsandthesoilweresimulatedbyasystemconsistingofnonlinearsprings,dashpotsandmasses,tostudythedeformationpropertiesofthereinforcedsoil.Theequivalentstiffnessanddampingratioscouldbedeterminedwiththeshakingtable.Thedynamicresponsesofareinforcedsubgradewereanalyzedwiththe3Dfiniteelementapproach.Thisapproachisprogrammedandappliedtoanalyzethesoilogeogridinteractionunderdynamicloading.Thecomparativeanalysisoftheresponseofthereinforcedsubgradeandthatofthesubgradewithoutreinforcementshowsthatthegeogridplacedatthebottomofthebaselayermayeffectivelyreducetheaccumulativeplasticdeformationduetothecyclicautomobileloading.

简介：AconstitutiveequationtheoryofOldroydfluidBtype,i.e.theco-rotationalderivativetype,isdevelopedfortheanisotropic-viscoelasticfluidofliquidcrystalline(LC)polymer.Analyzingtheinfluenceoftheorientationalmotiononthematerialbehaviorandneglectingtheinfluence,theconstitutiveequationisappliedtoasimplecaseforthehydrodynamicmotionwhentheorientationalcontributionisneglectedinitandtheanisotropicrelaxation,retardationtimesandanisotropicviscositiesareintroducedtodescribethemacroscopicbehavioroftheanisotropicLCpolymerfluid.UsingtheequationfortheshearflowofLCpolymerfluid,theanalyticalexpressionsoftheapparentviscosityandthenormalstressdifferencesaregivenwhichareinagoodagreementwiththeexperimentalresultsofBaeketal.Forthefiberspinningflowofthefluid,theanalyticalexpressionoftheextensionalviscosityisgiven.

简介：

简介：ThesedimentationsoftwocylindricalparticlesinthreedifferentinitialrelativepositionsarenumericallysimulatedusingthelatticeBoltzmannmethod.Themovementcharacteristicsandparticleinteractionsduringtheirsedimentationarepresentedanddiscussedindetail.Theresultsshowthat,(i)ifthetwoparticlesarereleasedparallelbutseparatedhorizontally,theypushawayeachother,rotateinwardsandseparatehorizontallyastheyfall;(ii)ifthetwoparticlesarereleasedparallelbutseparatedvertically,thesedimentationbehaviorcanbeclassifiedintothreestages:trailing,tumblingandseparating;(iii)ifthetwoparticlesarereleasedperpendicularbutseparatedvertically,thesedimentationbehaviorcanbecharacterizedas:trailingandrotating,touchingandsliding.Inordertovalidateoursimulation,experimentswerealsoconductedandtheresultsagreewellwiththenumericalones.

简介：TheaerodynamicforcesandflowstructureofamodelinsectwingisstudiedbysolvingtheNavier-Stokesequationsnumerically.Afteraninitialstartfromrest,thewingismadetoexecuteanazimuthalrotation(sweeping)atalargeangleofattackandconstantangularvelocity.TheReynoldsnumber(Re)consideredinthepresentnoteis480(Reisbasedonthemeanchordlengthofthewingandthespeedat60%winglengthfromthewingroot).Duringtheconstant-speedsweepingmotion,thestallisabsentandlargeandapproximatelyconstantliftanddragcoefficientscanbemaintained.Themechanismfortheabsenceofthestallorthemaintenanceoflargeaerodynamicforcecoefficientsisasfollows.Soonaftertheinitialstart,avortexring,whichconsistsoftheleading-edgevortex(LEV),thestartingvortex,andthetwowing-tipvortices,isformedinthewakeofthewing.Duringthesubsequentmotionofthewing,abase-to-tipspanwiseflowconvertsthevorticityintheLEVtothewingtipandtheLEVkeepsanapproximatelyconstantstrength.ThispreventstheLEVfromshedding.Asaresult,thesizeofthevortexringincreasesapproximatelylinearlywithtime,resultinginanapproximatelyconstanttimerateofthefirstmomentofvorticity,orapproximatelyconstantliftanddragcoefficients.Thevariationoftherelativevelocityalongthewingspancausesapressuregradientalongthewingspan.Thebase-to-tipspanwiseflowismainlymaintainedbythepressure-gradientforce.

简介：在干扰大的外界环境中,传统滤波法对组合导航系统进行状态估计的精度难以满足要求,为此提出了引入Elman神经网络.描述了它的状态估计的设计方法,对如何获取训练样本及网络的训练算法给予了详细的介绍,并把优化后的算法与原有方法进行仿真对比.最后以INS/GPS组合导航系统为例,分别用传统滤波法与Elman神经网络法进行状态估计.仿真结果证明了该法的有效性和实用性.

简介：在三轴整体式速率偏频激光陀螺无法进行输出轴冗余配置的情况下,为实现陀螺的元件级故障检测与隔离,提出了由三轴整体式速率偏频激光陀螺和挠性陀螺组构成的双惯性系统的故障检测与隔离方案,给出了双惯性系统的量测方程,并以此为基础推导了用于进行故障检测与隔离的奇偶方程.提出一种基于奇偶方程的双惯性系统故障检测与隔离方法,并针对一类无法用奇偶方程进行隔离的故障,给出一种搜索无故障陀螺输出轴的故障检测与隔离新方法.

简介：针对无阻尼惯导系统的误差特点,设计了适合航空应用的惯性(INS)/天文(CNS)/Doppler组合导航系统,建立了该组合导航系统卡尔曼滤波模型.仿真试验表明,该组合导航系统能为飞行体提供精确的导航信息.

简介：提出了一种利用GPS定位与测速相结合的动态定位方法.引入模糊人工神经网络技术对GPS数据进行处理,利用BP网络实现模糊化知识集的记忆和模糊判决的功能;最后,对处理前后的结果进行了对比.试验结果表明,该方法可以有效地提高GPS在开阔场地的定位精度.

简介：基于GPS测姿技术的发展,研究了以位置、速度和姿态信息作为观测量的INS/GPS组合导航系统的卡尔曼滤波算法.详细推导了这种组合方式的观测方程,并将该组合技术应用于某飞行器.仿真表明,增加姿态信息作为观测量可有效地提高系统导航参数的估计精度和速度.

简介：TheChineseSocietyofParticuologyisavoluntaryorganizationofworkersinresearch,developmentandapplicationofthescienceandtechnologyofparticles.TheSocietyisdedicatedtofostedngliaisonandexchangeamongitsmembersthroughscientificandtechnicalsymposiaandseminarsofbothanationalandinternationalnatureandtodisseminatingknowledgeonparticlesthroughcontinuingeducationandpublicationintheformofscientifictransactionsandofjournalsonnewsandotheritemsofcurrentinterest.Itsultimateobjectiveistoservethecountry'sneedsformodernization.

简介：publishesonlypapersofthehighestquality.Allpaperssubmittedaresenttorefereesfamiliarwiththerespectivesubjectsforadviceastotheireligibilityforpublicationandneededimprovement.TheEditorsmakethefinaldecisiononpublicationinthelightofsuchadvice.Non-nativeEnglish-speakingauthorsareadvisedtoseeknecessarylinguisticassistancebeforesubmissionoftheirmanuscripts,althoughtheEditorsarepreparedtohelpupgradeworksofexceptionalexcellence.Inadditiontofulllengthpapersofupto5000words,thejournalwelcomesreviews,correspondenceandshortercommunicationsoflessthan2500wordsdealingwithnovelresearchtechniques,analysisofcurrentresearch,newconcepts,etc.