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简介：Anenergy-dissipationbasedviscoplasticconsistencymodelispresentedtodescribetheperformanceofconcreteunderdynamicloading.Thedevelopmentofplasticityisstartedwiththethermodynamichypothesesinorderthatthemodelmayhaveasoundtheoreticalbackground.Independenthardeningandsofteningandtheratedependenceofconcretearedescribedseparatelyfortensionandcompression.AmodifiedimplicitbackwardEulerintegrationschemeisadoptedforthenumericalcomputation.Staticanddynamicbehaviorofthematerialisillustratedwithcertainnumericalexamplesatmaterialpointlevelandstructurallevel,andcomparedwithexistingexperimentaldata.Resultsvalidatetheeffectivenessofthemodel.

简介：Inthispaper,wediscusstheasymptoticnormalityofthewaveletestimatorofthedensityfunctionbasedoncensoreddata,whenthesurvivalandthecensoringtimesformastationaryα-mixingsequence.Tosimulatethedistributionofestimatorsuchthatitiseasytoperformstatisticalinferenceforthedensityfunction,arandomweightedestimatorofthedensityfunctionisalsoconstructedandinvestigated.Finitesamplebehavioroftheestimatorisinvestigatedviasimulationstoo.更多还原

简介：TostudytheroIesofMomentumDependentInteraction(MDI)inthefragmentationdtietothecouplingbetweentheisospindependenceofthetwo-bodycollisionsandMDI,westudy,byusingIsospin-dependentQuantumMolecularDynamicsmodel,thetimeevolutionsofthevariationofthe△N_(imf)(△σ,U_1~(sym))withtheMDIandwithoutit(NOMDI).Thequantityisdefinedas

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简介：Soilconsolidationwouldinducevariationsofitstransportcoefficientssuchashydraulicconductivityanddiffusioncoefficient.Thispaperpresentsastudyoftheinfluenceofbarrierconsolidationontransportcoefficients,anda3Dtransportmodelbasedonmixturetheoryisproposedfordescribingthelinersthatinvolvecirculardefectsinthegeomembrane.TheelastoplasticALPHAmodelisrevisedbyusingthespatiallymobilizedplane(SMP)criterionforsimulatingthedeformationofthesoils.Then,the3Dmodelcouplingthenonlinearconsolidationandcontaminantadvection-diffusionissolvedusingthefiniteelementsoftwareABAQUS.Theresultsshowthattheimportanceofreducingthedefectsizeinthegeomembraneandthelinerporositytocontrolthecontaminantconcentrationincrease.

简介：Astudyconcerningtheeffectofvibrationonthecrystalstructureandmorphologyforisotacticpolypropylene(iPP)wasconducted.Thecrystallitesize.crystalstructureandcrystallinityofiPPunderorwithoutvibrationtreatmentwereinvestigatedbymeansofdifferentialscanningcalorimetry(DSC)andwideangleX-raydiffraction(WAXD).Theresultsrevealthatthecrystallinityofthevibratedsamplesdecreasesatahighcoolingrate,butitremainsconstantatalowcoolingratebecauseofthechainrelaxationofiPP.Ithasbeenfoundthatvibrationobviouslyincreasesthecontentofβ-formofcrystalphaseandtheamountofβ-crystalmainlydependsonthevibrationamplitude.

简介：在这篇文章，population-size-dependent两性恋者Galton-Watson过程被考虑。在交配功能和后代分发上的一些合适的条件下面，吝啬的生长率的限制的存在每交配联合起来被证明。并且基于限制，识别这个过程是否承认的一个标准最终与概率绝灭一个人被获得。

简介：非相对论的量力学的明白地计量器不变的明确的表达在磁性的偶极子近似被用于时间依赖者泛音振荡器的盒子。为获得计量器不变的转变概率振幅的一个一般方程被导出。

简介：Inthepaper,thestrongconvergencepropertiesfortwodifferentweightedsumsofnegativelyorthantdependent(NOD)randomvariablesareinvestigated.Let{Xn,n≥1}beasequenceofNODrandomvariables.Theresultsobtainedinthepapergeneralizethecorrespondingonesfori.i.d.randomvariablesandidenticallydistributedNArandomvariablestothecaseofNODrandomvariables,whicharestochasticallydominatedbyarandomvariableX.Asabyproduct,theMarcinkiewicz-ZygmundtypestronglawoflargenumbersforNODrandomvariablesisalsoobtained.

简介：Piezoelectricsuperlatticeisapotentialcomponentfornanoelectromechanicalsystems.Duetothestrongnonlocaleffectsuchasflexoelectriceffectatinterfaces,classicalpiezoelectrictheoryisunabletoaccuratelydescribetheelectromechanicalresponseofpiezoelectricsuperlatticeatnanoscalescale.BasedonthepreviousnonlocalthermodynamicstheorywithflexoelectriceffectLiuetal.(2016),thesizedependentelectromechanicalpropertiesofpiezoelectricsuperlatticesmadeofBaTiO_3(BTO)andPbTiO_3(PTO)layersareinvestigatedsystematicallyinthepresentwork.GiantstraingradientisfoundneartheinterfacebetweenBTOandPTOlayers,whichleadstothesignificantenhancementofpolarizationinthesuperlatticeduetotheflexoelectriceffect.ForthepiezoelectricBTO–PTOsuperlatticeswithdifferentunitcellsizes,thethicknessofinterfacewithnontrivialstraingradientisalmostconstant.Theinfluenceofstraingradientattheinterfacebecomessignificantwhenthesizeofsuperlatticedecreases.Asaresult,astrongsizedependenceofelectromechanicalpropertiesispredictedforthepiezoelectricBTO–PTOsuperlattices.Inparticular,forthesuperlatticeswithaspecificthicknessratioofBTOandPTOlayers,thepiezoelectricresponsecanbeseveraltimeslargerthanthatofbulkstructure.Thepresentworkdemonstratesapracticalwaytodesignthepiezoelectricsuperlatticeswithhighpiezoelectriccoefficientbyusingthenonlocaleffectatnanoscale.

简介：Thisletterpresentsatheoreticalmodelofthenormal(head-on)collisionsbetweentwosoftspheresforpredictingtheexperimentalcharacteristicofthecoefficientofrestitutiondependentonimpactvelocity.Afterthecontactforcelawbetweenthecontactedspheresduringacollisionisphenomenologicallyformulatedintermsofthecompressionoroverlapdisplacementunderconsiderationofanelastic-plasticloadingandaplasticunloadingsubprocesses,thecoefficientofrestitutionisgainedbythedynamicequationofthecontactprocessonceaninitialimpactvelocityisinput.Itisfoundthatthetheoreticalpredictionsofthecoefficientofrestitutionvaryingwiththeimpactvelocityarewellinagreementwiththeexistingexperimentalcharacteristicswhicharefittedbytheexplicitformula.

简介：Uniaxialtensiletestingatstrainratesrangingfrom10-3to10-1s-1wascarriedouttostudytherate-dependentme-chanicalbehaviorforpoly(ethyleneterephthalate)(PET)usedinthepackagingindustry.Theexperimentalresultsshowthatarate-dependentplasticbehaviorexistsforPETmaterial.Thevalueoftheyieldstrengthwasfoundtoincreasewiththeincreasingstrainrate.AnewconstitutivemodelbasedontheimprovedCowper-Symondsrate-dependentconstitutivemodelisproposedtodescribethemechanicalbehaviorofPETmaterialinthestrainraterangingfrom10-3to10-1s-1,providingmoreaccuratematerialdataforthesubsequentsimulationanalysisofdroptestanddynamicbuckling.ThepredictionsobtainedusingtheproposedmodelarecomparedwithexperimentalresultsoftheimprovedCowper-Symondsmodel.Thesimulatingresultsoftheproposedmodelagreewellwiththeexperimentaldata.Foralowstrainrate,thepredictionsofthismodelaremoreprecisethanthoseobtainedusingtheimprovedCowper-Symondsmodel.Thisconfirmsthatthenewconstitutivemodelissuitablefordescribingtheme-chanicalbehaviorofPETmaterialatalowstrainrateandmodelingimpactproblem.

简介：Thispaperreportsthatpolarizedfar-infraredreflectivitymeasurementshavebeendoneonLiGaO2singlecrystalalongtwocrystallineaxesatdifferenttemperatures.Thetemperaturedependentfrequenciesofthelongitudinalandtransverseopticalphononhavebeenobtainedfromtherealpartofopticalconductivityandthelossfunctionrespectively.AsmallDrudecomponentisobservedatfrequencybelow300cm-1whichcouldarisefromLiionsoroxygendeficiencies.TheionicityofLiGaO2hasbeenstudiedfromtheanalysisoftheBorneffectivechargeofdifferentions.

简介：Theclassofpopulation-size-dependentbranchingprocessesinindependentidenticallydistributedrandomenvironmentsisinvestigated.Underthecriticalcaseandappropriatemomentassumption,weestablishanasymptoticestimateofthesurvivalprobabilityatgenerationn.

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简介：Adelayedsemi-ratio-dependentpredator-preysysteminaperiodicenvironmentisinvestigatedinthispaper.ByusingacontinuationtheorembasedonGainesandMawhin'scoincidencedegree,theglobalexistenceofpositiveperiodicsolutionisstudied.Asetofeasilyverifiablesufficientconditionsareobtained.