简介:TheMelnikovmethodwasextendedtoperturbedplanarnon-Hamiltonianintegrablesystemswithslowly-varyingangleparameters.Basedontheanalysisofthegeometricstructureofunperturbedsystems,theconditionoftransverselyhomoclinicintersectionwasestablished.ThegeneralizedMelnikovfunctionoftheperturbedsystemwaspresentedbyapplyingthetheoremonthedifferentiabilityofordinarydifferentialequationsolutionswithrespecttoparameters.ChaosmayoccurinthesystemifthegeneralizedMelnikovfunctionhassimplezeros.
简介:Amultilayerflowisastratifiedfluidcomposedofafinitenumberoflayerswithdensitieshomogeneouswithinonelayerbutdifferentfromeachother.Itisanintermediatesystembetweenthesingle-layerbarotropicmodelandthecontinuouslystratifiedbaroclinicmodel.Sincethissystemcansimulatethebarocliniceffectsimply,itiswidelyusedtostudythelarge-scaledynamicprocessinatmosphereandocean.Thepresentpaperisconcernedwiththelinearstabilityofthemultilayerquasi-geostrophicflow,andtheassociatedlinearstabilitycriteriaareestablished.Firstly,thenonlinearmodelisturnedintotheformofaHamiltoniansystem,andabasicflowisdefined.ButitcannotbeanextremepointoftheHamiltonianfunctionsincethesystemisaninfinite-dimensionalone.Therefore,itisnecessarytoreconstructanewHamiltonianfunctionsothatthebasicflowbecomesanextremepointofit.Secondly,thelinearizedequationsofdisturbancesinthemultilayerquasi-geostrophicflowarederivedbyintroducinginfinitesimaldisturbancessuperposedonthebasicflows.Finally,thepropertiesofthelinearizedsystemarediscussed,andthelinearstabilitycriteriainthesenseofLiapunovarederivedundertwodifferentconditionswithrespecttocertainnorms.
简介:Uponusingthedenotativetheoremofanti-HermitiangeneralizedHamiltonianmatrices,wesolveeffectivelytheleast-squaresproblemmin‖AX-B‖overanti-HermitiangeneralizedHamiltonianmatrices.WederivesomenecessaryandsufficientconditionsforsolvabilityoftheproblemandanexpressionforgeneralsolutionofthematrixequationAX=B.Inaddition,wealsoobtaintheexpressionforthesolutionofarelevantoptimalapproximateproblem.
简介:Newton定律是描述物体运动的基本定律,Hamiltonian方程则为运动的基本规律提供了另外一种表达。由Hamiltonian方程发展而来的Hamiltonian可积系统是现代孤立子理论的重要组成部分。文中证明了一个关于Korteweg—devries(KdV)类型的非线性发展方程的在加权Sobolev空间中的估计式。这一估计式对证明一类一般的非线性扩散型发展方程的不变性质是非常有用的。