简介:StudiesofthermalizationprocessesofenergeticchargedparticlesproducedinD-He^3fusionreactionsareveryimportantforcalculationsoftheirslowingdowntime,energyfractiontransferredtobackgroundionsandelectronsandfastionpressure(thatmeansfastionβ).Basedontheassumptionofbinarycollision,thetotalrateofenergylossofthetestparticleequalstothesumovertheratsofenergylossestotheelectronandallionspecies.Forthesecalculations,
简介:Theinitialvalueproblemsandthefirstboundaryproblemsforthequasilinearwaveequationutt-[a0+na1(ux)n-1]uxx-a2uxxtt=0areconsidered,wherea0,a2>0areconstants,a1isanarbitraryrealnumber,nisanaturalnumber.Theexistenceanduniquenessoftheclassicalsolutionsfortheinitialvalueproblemsandthefirstboundaryproblemsoftheequation(1)areprovedbytheGalerkinmethod.
简介:Thispaperpresentsatwo-stepexplicitmethodoforderfourforsolvingaclassoflinearperiodicinitialvalueproblems.Ateachcomputationalstep,onlytworightfunctionevaluationsandonederivativeevaluationareemployed.Basingonaspecialvectoroperation,themethodcanbeextendedtothevector-applicableinmulti-dimensionalspace.
简介:Aprobabilistieprogressivefailureanalyzingmethodisappliedtoestimatingthereliabilityofasimplysupportedlaminatedeompositeplatewithaninitialimperfectionunderbi-axialeompressionload.Theinitialimperfectionandthestrengthparametersareconsideredasrandomvariables.Ply-levelfailureproba-bilityisevaluatedbythefirstorderreliabilitymethod(FORM)togetherwiththeTsai-WustrengtheriterionandTancriterion.Currentstressesinthelaminatedstructurearecalculatedbytheclassicallaminationtheorywiththestiffnessmodifiedbasedonthelaststepplyfailure.Probabilistieallydominantply-levelfailurese-quencesleadingtooverallsystemfailureareidentified,basedonwhichthesystemfailureprobabilityisesti-mated.Anumeriealexampleispresentedtodemonstratethemethodologyproposed.Throughparameterstud-iesitisshownthatthedeviationoftheinitialimperfeetionandsomeofthestrengthparameterslargelyinflu-encethesystemreliability.
简介:Thisstudyinvestigatedcharacteristicsofbifurcationandcriticalbucklingloadbyshapeimperfectionofspacetruss,whichweresensitivetoinitialconditions.Thecriticalpointandbucklingloadwerecomputedbytheanalysisoftheeigenvaluesanddeterminantsofthetangentialstiffnessmatrix.Thetwo-free-nodesexampleandstardomewereselectedforthecasestudyinordertoexaminethenodalbucklingandglobalbucklingbythesensitivitytotheeigenbucklingmodeandtheanalysesoftheinfluence,andcharacteristicsoftheparametersasdefinedbytheloadratioofthecenternodeandsurroundingnode,aswellasrise-spanratiowereperformed.Thesensitivitytotheimperfectionoftheinitialshapeofthetwo-free-nodesexample,whichoccursduetosnappingatthecriticalpoint,resultedinbifurcationbeforethelimitpointduetothebucklingmode,andthebucklingloadwasreducedbytheincreaseintheamountofimperfection.Thetwosensitivebucklingpatternsofthenumericalmodelareestablishedbyinvestigatingthedisplacedpositionofthefreenodes,andtheasymmetriceigenmodegreatlyinfluencedthebehavioroftheimperfectionshapewhetheritwasatlimitpointorbifurcation.Furthermore,thesensitivemodeofthetwo-free-nodesexamplewassimilartothein-extensionalbasismechanismofasimplifiedmodel.Thestardome,whichwasusedtoexaminetheinfluenceamongseveralnodes,indicatedthattheinfluenceofnodalbucklingwasgreaterthanthatofglobalbucklingastherise-spanratiowashigher.Besides,globalbucklingisoccurredwithreachingbifurcationpointasthevalueofloadratiowashigher,andthebucklingloadlevelwasabout50%-70%ofloadlevelatlimitpoint.
简介:Thedeactivationbehaviorbycrystallitegrowthofnickelnanoparticlesonvarioussupports(carbonnanofibers,zirconia,SiC,α-Al_2O_3andγ-Al_2O_3)wasinvestigatedintheaqueousphasereformingofethyleneglycol.SupportedNicatalystsof~10wt%werepreparedbyimpregnationofcarbonnanofibers(CNF),ZrO_2,SiC,γ-Al_2O_3andα-Al_2O_3.TheextentoftheNinanoparticlegrowthonvarioussupportmaterialsfollowstheorderCNF~ZrO_2>SiC>γ-Al_2O_3>>α-Al_2O_3whichsequence,however,wasdeterminedbytheinitialNiparticlesize.Basedontheobservednickelleachingandthespecificgrowthcharacteristics;theparticlesizedistributionandtheeffectofloadingonthegrowthrate,Ostwaldripeningissuggestedtobethemainmechanismcontributingtonickelparticlegrowth.Remarkably,initiallysmallerNiparticles(~12nm)supportedonα-Al_2O_3werefoundtooutgrowNiparticleswithinitiallylargersize(~20nm).ItisputforwardthatthehighersusceptibilitywithrespecttooxidationofthesmallerNinanoparticlesanddifferencesininitialparticlesizedistributionareresponsibleforthisbehavior.
简介:Thewell-posednessoftheinitialvalueproblemoftheEulerequationswasmainlydiscussedbasedonthestratificationtheory,andthenecessaryandsufficientconditionsofwell-posednessarepresentedforsomerepresentativeinitialorboundaryvalueproblem,thusthestructureofsolutionspaceforlocal(exact)solutionoftheEulerequationsisdetermined.Moreoverthecomputationformulasoftheanalyticalsolutionofthewell-posedproblemarealsogiven.
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简介:Theauthorconsidersthelife-spanofclassicalsolutionstoCauchyproblemforgeneralfirstorderquasilinearstrictlyhyperbolicsystemsintwoindependentvariableswith"slow"decayinitialdata.Byconstructinganexample,firstitisillustratedthattheclassicalsolutiontothiskindofCauchyproblemmayblowupinafinitetime,evenifthesystemisweaklylinearlydegenerate.Thensomelowerboundsofthelife-spanofclassicalsolutionsaregiveninthecasethatthesystemisweaklylinearlydegenerate.Theseestimatesimplythat,whenthesystemisweaklylinearlydegenerate,theclassicalsolutionexistsalmostgloballyintime.Finally,itisprovedthatTheorems1.1-1.3in[2]arestillvalidforthiskindofinitialdata.
简介:在内部消散的条件下面,为不同类的quasilinear的Cauchy问题有小起始的数据的夸张系统承认唯一的全球C1个答案,指数地作为t+腐烂到零,当时如果边界条件的系数矩阵满足边界消散的状况,有为有至少秒的非线性的条款的夸张系统订的quasilinear的小起始的数据的混合的起始边界的值问题承认唯一的g在这份报纸,在更一般的条件下面,作者调查内部消散的条件和边界的联合效果消散的状况,并且证明全球存在和C的指数的腐烂为quasilinear的混合的起始边界的值问题的1个答案有小起始的数据的夸张系统。这稳定性结果被用于一种模型,并且一个例子被给看可能的指数的不稳定性相应条件是否没满足。