简介:Abstract.OgrobjectinthisartlcleistodescribetbeGalerklnschemeandnonlin-eaxGalerkinschemefortheapproximationofnonlinearevolutionequations,andtostudythestabilityoftheseschemes.SpatialdiscretizatloncanbepedormedbyeitherGalerklnspectralmethodornonlinearGalerldnspectralmethod;timediscretizatlortisdonehyEulersin.heinewklchisexplicitorimplicitinthenonlinearterms.Accordingtothestabilityanalysisoftheaboveschemes,thestabilityofnonllneexGalerklnmethodisbetterthanthatofGalexklnmethod.
简介:IntroductionTheconceptsofInertialManifold(IM)[1]andApproximateInertialManifold(AIM)[2]fordissipativepartialdifferentialequati...
简介:TheGalerkinandleast-squaresmethodsaretwoclassesofthemostpopularKrylovsubspacemethOdsforsolvinglargelinearsystemsofequations.Unfortunately,boththemethodsmaysufferfromseriousbreakdownsofthesametype:InabreakdownsituationtheGalerkinmethodisunabletocalculateanapproximatesolution,whiletheleast-squaresmethod,althoughdoesnotreallybreakdown,isunsucessfulinreducingthenormofitsresidual.Inthispaperwefrstestablishaunifiedtheoremwhichgivesarelationshipbetweenbreakdownsinthetwometh-ods.Wefurtherillustratetheoreticallyandexperimentallythatifthecoefficientmatrixofalienarsystemisofhighdefectivenesswiththeassociatedeigenvalueslessthan1,thentherestart-edGalerkinandleast-squaresmethodswillbeingreatrisksofcompletebreakdowns.Itappearsthatourfindingsmayhelptounderstandphenomenaobservedpracticallyandtoderivetreat-mentsforbreakdownsofthistype.
简介:摘要:采用无单元 Galerkin 方法数值求解具有狄利克雷边界条件的二维瞬态热传导问题。首先离散该问题的时间变量,将该问题 转化为与时间无关的边值问题;然后采用罚函数法处理 Dirichlet 边界条件,得到数值离散方程组,再利用 Matlab 软件求解给出的算例,结果表明该方法得到的数值结果与解析解吻合较好,该方法具有较高的计算精度和较好的收敛性。
简介:目的建立银翘解毒丸(YinqiaoJiedupill,YQJDP)高效液相色谱数字化指纹谱(N-FP)、对数指纹谱(ln-FP)、平方谱(S-FP)和反向谱(R-FP)。方法应用"中药色谱指纹图谱超信息特征数字化评价系统4.0"软件计算46个数字化参数进行潜信息特征数字化评价。用系统指纹定量法(systematicallyqualifiedfingerprintmethod,SQFM)评价YQJDPs在4种指纹谱图谱模式下的质量等级。结果在N-FP下15批YQJDPs的质量为:S3-S6及S8质量为1级;S2为3级;S7为2级,DS1-DS4及WS1-WS2质量为8级。结论本文所建立的多维指纹图谱评价方法可清晰地揭示YQJDPs超信息数字化特征,对数指纹谱能有效揭示中药指纹图谱各峰的均化性特征,消除批间差异增加指纹共性特征。平方谱和反向谱则能分别强调大峰和小峰在中药质量评价中的特异性作用。本文为中药指纹图谱合理评价中药质量提供一种参考方法。
简介:Inthispaper,weareconcernedwithuniformsuperconvergenceofGalerkinmethodsforsingularlyperturbedreaction-diffusionproblemsbyusingtwoShishkin-typemeshes.Basedonanestimateoftheerrorbetweensplineinterpolationoftheexactsolutionanditsnumericalapproximation,aninterpolationpost-processingtechniqueisappliedtotheoriginalnumericalsolution.Thisresultsinapproximationexhibitsuperconvergencewhichisuniformintheweightedenergynorm.Numericalexamplesarepresentedtodemonstratetheeffectivenessoftheinterpolationpost-processingtechniqueandtoverifythetheoreticalresultsobtainedinthispaper.
简介:Inthispaper,theminimaldissipationlocaldiscontinuousGalerkinmethodisstudiedtosolvetheellipticinterfaceproblemsintwo-dimensionaldomains.Theinterfacemaybearbitrarysmoothcurves.ItisshownthattheerrorestimatesinL2-normforthesolutionandthefluxareO(h2|logh|)andO(h|logh|^l/2),respectively.Innumericalexperiments,thesuccessivesubstitutioniterativemethodsareusedtosolvetheLDGschemes.Numericalresultsverifytheefficiencvandaccuracvofthemethod.
简介:ItisprovedinthispaperthattheapproximatesolutionofthediscontinuousGalerkinmethoddoesconvergeeventheexactsolutionofthefirstorderhyperbolicequationisdiscontinuous.
简介:AD(Alternatingdirection)Galerkinschemesford-dimensionalnonlinearpseudo-hyperbolicequationsarestudied.Byusingpatchapproximationtechnique,ADprocedureisrealized,andcalculation,workissimplified.ByusingGalerkinapproach,highlycomputationalaccuracyiskept.Byusingvariousprioriestimatetechniquesfordifferentialequations,difficultycomingformnon-linearityistreated,andoptimalH^1andL^2convergenceprop-ertiesaredemonstrated.Moreover,althoughalltheexistedADGalerkinschemesusingpatchapproximationarelimitedtohaveonlyoneorderaccuracyintimeincrement,yettheschemesformulatedinthispaperhavesecondorderaccuracyinit.ThisimpliesanessentialadvancementinADGalerkinaualysis.
简介:Akindofcalculatingmethodforhighorderdifferentialsexpandedbythewaveletscal-ingfunctionsandtheintegraloftheirproductusedinGalerkinFEMisproposed,sothatwecanusethewaveletGalerkinFEMtosolveboundary-valuedifferentialequationswithordershigherthantwo.TocombinethismethodwiththeGeneralizedGaussianintegralmethodinwavelettheory,wecanfindthatthismethodhasmanymeritsinsolvingmechanicalproblems,suchasthebendingofplatesandthosewithvariablethickness.Thenumericalresultsshowthatthismethodisaccurate.
简介:使用高阶间断Galerkin(discontinuousGalerkin,DG)方法求解双曲守恒律方程组时,非物理效应常常导致计算过程的中断,这在很大程度上制约着该方法在计算流体力学中的应用.文章结合局部单元上原始流动变量的Taylor展开,设计了一种新型的限制器,通过对各阶空间导数的重构,有效地消除了非物理振荡的不利影响.对二维Euler方程的计算结果表明,该限制器不仅能够捕捉高质量的激波,而且能够保证残值的有效收敛.
简介:几个Galerkin-Petrov方法,包括的多项式搭配和分析元素的集中在Dirichlet空间的Toeplitz操作员的搭配方法,被建立。特别地,如果基础和测试功能拥有某些圆形的对称,如此的方法收敛,这被显示出。给词调音:GalerkinPetrov方法;多项式搭配;分析元素搭配;Toeplitz操作员;Dirichlet空间
简介:Weperformanalysisforafiniteelementsmethodappliedtothesingularself-adjointproblem.Thismethodusescontinuouspiecewisepolynomialspacesforthetrialandthetestspaces.WefitthetrialpolynomialspacebypiecewiseexponentialsandweapplysoexponentiallyfittedGalerkinmethodtosingularself-adjomtproblembyapproximatingdrivingtermsbyLagrangepiecewisepolynomials,linear,quadraticandcubic.Wtmeasuretheerroeinmaxnorm.Weshowthatmethodisoptimalofthefirstorderintheerrorestimate,WealsogivenumericalresultsfortheGalerkinapproximation.
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