简介:Inthispaper,weconsiderexistenceanduniquenessofpositivesolutionstothreecouplednonlinearSchrdingerequationswhichappearinnonlinearoptics.Weusethebehaviorsofminimizingsequencesforaboundtoobtaintheexistenceofpositivesolutionsforthreecoupledsystem.Toprovetheuniquenessofpositivesolutions,weusetheradialsymmetryofpositivesolutionstotransformthesystemintoanordinarydifferentialsystem,andthenintegratethesystem.Inparticular,forN=1,weprovetheuniquenessofpositivesolutionswhen0≤β=μ1=μ2=μ3orβ>max{μ1,μ2,μ3}.
简介:Considerasystemofnonlinearwaveequations(e)2t-c2i△xui=Fi(u,(e)u,(e)x(e)u)in(0,∞)×(R)3fori=1,┈,m,whereFi(i=1,┈,m)aresmoothfunctionsofdegree2neartheoriginoftheirarguments,andu=(u1,┈,um),while(e)uand(e)x(e)urepresentthefirstand(secondderivativesofu,respectively.Inthispaper,theauthorpresentsanewclassofnonlinearityforwhichtheglobalexistenceofsmallsolutionsisensured.Forexample,globalexistenceofsmallsolutionsfor((e)2t-c21Δx)u1=u2((e)tu2)+arbitrarycubicterms,((e)2t-c22Δx)u2=u1((e)tu2)+((e)tu1)u2+arbitrarycubictermswillbeestablished,providedthatc21≠c22.
简介:ThediscreteSobolev’sinequalitiesinL_pnormareprovedforthree-dimensionalsphericalandcylindricalcoordinates,byusingdiscreteHolderinequality.propertyofthetrianglefunctionsandcomplicateddeduction.
简介:Thepurposeofthispaperistoinvestigatesomesufficientandnecessaryconditionsforthree-stepIshikawaiterativesequenceswitherrortermsforuniformlyquasi-Lipschitzianmappingstoconvergetofixedpoints.OurresultsextendandimprovetherecentonesannouncedbyLiu[3,4],XuandNoor[5],andmanyothers.
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简介:Weusetheincrementalunknownsmethodinconjunctionwiththeiterativemethodstoapproximatethesolutionofthenonsymmetricandpositive-definitelinearsystemsgeneratedfromamultileveldiscretizationofthree-dimensionalconvection-diffusionequations.Theconditionnumbersofincrementalunknownsmatricesassociatedwiththeconvection-diffusionequationsandthenumberofiterationsneededtoattainanacceptableaccuracyareestimated.Numericalresultsarepresentedwithtwo-levelapproximations,whichdemonstratethattheincrementalunknownsmethodwhencombinedwithsomeiter-ativemethodsisveryeffcient.
简介:InthepresentpaperweintroducearandomiterationschemeforthreerandomoperatorsdefinedonaclosedandconvexsubsetofauniformlyconvexBanachspaceandproveitsconvergencetoacommonfixedpointofthreerandomoperators.Theresultisalsoanextensionofaknowntheoreminthecorrespondingnon-randomcase.
简介:Thesoftwareforoil-gastransportandaccumulationistodescribethehistoryofoil-gastransportandaccumulationinbasinevolution.Itisofgreatvalueinrationalevaluationofprospectingandexploitingoil-gasresources.Themathematicalmodelcanbediscribedasacoupledsystemofnonlinearpartialdifferentialequationswithmovingboundaryvalueproblem.Foragenericcaseofthethree-demensionalboundedregion,bithisthesis,theeffectsofgravitation、buoyancyandcapillarypressureareconsidered,weputforwardakindofcharacteristicfinitedifferenceschemesandmakeusethickandthingridstoformacompleteset,andofcalculusofvaviations,thechangeofvariable,thetheoryofpriorestimatesandtechniques,Optimalorderestimatesinl~2normarederivedfortheerrorinapproximateassumption,Thuswehavecompletelysolvedthewell-knowntheoreticalproblemproposedbyJ.Douglas,Jr.
简介:Thispaperpresentsalternatingdirectionfinitevolumeelementmethodsforthree-dimensionalparabolicpartialdifferentialequationsandgivesfourcomputationalschemes,oneisanalogoustoDouglasfinitedifferenceschemewithsecond-ordersplittingerror,theothertwoschemeshavethird-ordersplittingerror,andthelastoneisanextendedLODscheme.TheL2normandH1semi-normerrorestimatesareobtainedforthefirstschemeandsecondone,respectively.Finally,twonumericalexamplesareprovidedtoillustratetheefficiencyandaccuracyofthemethods.
简介:FOURIER-CHEBYSHEVSPECTRALMETHODFORSOLVINGTHREE-DIMENSIONALVORTICITYEQUATIONGUOBENYU(郭本瑜);LIJIAN(李健);MAHEPING(马和平)(Departmento...
简介:Inthispaper,bifurcationofsmallamplitudelimitcyclesfromthedegenerateequilibriumofathree-dimensionalsystemisinvestigated.Firstly,themethodtocalculatethefocalvaluesatnilpotentcriticalpointoncentermanifoldisdiscussed.Thenanexampleisstudied,bycomputingthequasi-Lyapunovconstants,theexistenceofatleast4limitcyclesonthecentermanifoldisproved.Intermsofdegeneratesingularityinhigh-dimensionalsystems,ourworkisnew.
简介:Inthispaper,Chebyshevpseudospectral-finiteelementschemesareproposedforsolvingthreedimensionalvorticityequation.SomeapproximationresultsinnonisotropicSobolevspacesaregiven.Thegeneralizedstabilityandtheconvergenceareprovedstrictly.Thenumericalresultsshowtheadvantagesofthismethod.Thetechniqueinthispaperisalsoapplicabletootherthree-dimensionalnonlinearproblemsinfluiddynamics.