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二阶泛函常微分方程解的振动性与非振动性 总被引:2,自引:0,他引:2
张炳根 《数学年刊A辑(中文版)》1981,(1)
对于二阶线性常微分方程由Sturm定理知,方程(1)的解或者都是振动、或者都是非振动。所谓一个解y(t)为振动的,是指当t→∞时,y(t)具有没有尽头的零点。于是,非振动解y(t)是指存在某一有限时刻T,当t>T后,y(t)不再有零点。 相似文献
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带强迫项高阶中立型微分方程的振动性和非振动性 总被引:1,自引:0,他引:1
我们给出一类强迫高阶非线性中立型时滞微分方程一切解振动的充分条件.而且,也研究了一类强迫一阶中立型方程非振动解的渐近性. 相似文献
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证明了线性脉冲中立型时滞微分方程解的振动性等价于一类非脉冲中立型时滞微分方程解的振动性,应用这一结果建立了此类线性脉冲中立型微分方程解的振动性的显示判据。 相似文献
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《高校应用数学学报(A辑)》2018,(4)
主要考虑了一类红细胞模型数值解的振动性,通过振动性的理论将非线性延迟微分方程转化为相应的线性延迟微分方程,再利用线性θ-方法,得到相应的差分方程,从而得到数值解振动的条件以及非振动解的渐近性质.为了更好的说明结果,最后给出了一些算例. 相似文献
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在α>1,且0<β<α情性下研究了高阶具非线性中立项不稳定型时滞微分方程[x(t)-pxα(t-τ)](n)=q(t)xβ(t-σ),(t≥t0)的振动和非振动性.利用一些新的技巧,获得了上述方程有界解振动的振动准则和至少存在一个非振动解的非振动准则,所得结果补充和推广了已有文献部分结果. 相似文献
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脉冲中立型时滞微分方程的振动性 总被引:12,自引:0,他引:12
本文证明了线性脉冲中立型微分方程解的振动性等价于一类线性非脉冲中立型时滞微分方程解的振动性.应用这一结果,建立了线性脉冲中立型方程解振动性的显式判据.这些判别条件,显著地改进了已有的结果. 相似文献
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脉冲中立型时滞微分方程的振动性 总被引:9,自引:0,他引:9
燕居让 《数学年刊A辑(中文版)》2000,(6)
本文证明了线性脉冲中立型微分方程解的振动性等价于一类线性非脉冲中立型时滞微分方程解的振动性.应用这一结果,建立了线性脉冲中立型方程解振动性的显式判据.这些判别条件,显著地改进了已有的结果. 相似文献
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Multiple solutions are reported for the two-dimensional boundary layer flow of a viscous fluid near a permeable wall through which fluid is uniformly withdrawn. In the limit of large wall suction, three flows of similarity form are found: the first is the well-known monotonic solution of Terrill; the second exhibits flow reversal, with the streamlines being separated into three distinct cells; the third also exhibits flow reversal, but has multiple cells only when the fluid withdrawal speed is less than some threshold. The wall injection problem is also briefly studied, only Terrill's branch of solutions being found. Numerical and asymptotic solutions are presented and compared; the large-suction asymptotics of the third solution branch are found to be rather subtle. 相似文献
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方沛辰 《数学的实践与认识》2005,35(7):98-105
对2004年首届研究生数学建模竞赛的C题“售后服务数据的运用”在竞赛中学生们做出的各种作法给予了评述,同时给出评卷时的评分标准和一个参考解答. 相似文献
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利用上下解方法及单调迭代技术讨论了一类具有上确界的二阶非线性脉冲微分方程无穷边值问题,给出了其最小最大解存在定理. 相似文献
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§ 1. Introduction Inthispaperwewillconsidertheproblemoftheformofalgebraicdifferentialequationwithadmissiblemeromorphicsolution[Ω1 (z ,w) /Ω2 (z ,w) ] m =∑nj=0aj(z)wj,(1 )whereΩ1 (z,w) =∑(i)a(i) (z)wi0 (w′) i1… (w(n) ) in,Ω2 (z,w) =∑( j)b( j) (z)wj0 (w′) j1… (w(n) ) jn,(i) ,(j)arefiniteindexsets,{ai(z) } ,{a(i) (z) }and {a(i) (z) }aremeromorphicfunctions,T(r,a(i) ) =o(T(r,w) ) ,T(r,ai) =o(T(r ,w) ) ,T(r,b(j) ) =o(T(r ,w) ) .Letw(z)beameromorphicsolutionof (1 ) .Ifw(z)satisfies… 相似文献
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Meng Fan Ke WangDepartment of Mathematics Key Laboratory for Vegetation Ecology of the Ministry of Education of China Northeast Normal University Changchun China 《应用数学学报(英文版)》2002,(2)
Abstract With the help of a continuation theorem based on Gaines and Mawhin's coincidence degree,westudy the global existence of positive periodic solutions of a "food-limited" population model with toxicants andtime delays.Some new results are obtained. 相似文献
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ZHANG Xi-cheng 《数学杂志》2021,(1):1-4
In this note we announce the global boundedness for the solutions to a class of possibly degenerate parabolic equations by De-Giorgi’s iteration.In particular,the existence of weak solutions for possibly degenerate stochastic differential equations with singular diffusion coefficients is obtained. 相似文献
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We use Brouwer degree to prove existence and multiplicity results for the periodic solutions of some nonlinear second order difference equations involving discrete -Laplacian. We obtain in particular upper and lower solutions theorems, Ambrosetti–Prodi type multiplicity results, sharp existence conditions for nonlinearities which are bounded from below or from above and necessary and sufficient conditions for the existence of positive periodic solutions when the nonlinearity is singular at 0. 相似文献
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In discrete maximization problems one usually wants to find an optimal solution. However, in several topics like “alignments,” “automatic speech recognition,” and “computer chess” people are interested to find thekbest solutions for somek ≥ 2. We demand that theksolutions obey certain distance constraints to avoid that thekalternatives are too similar. Several results for valuated -matroids are presented, some of them concerning time complexity of algorithms. 相似文献
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1IntroductionInthispaperweconsiderthefollowingneutraldifferentialequationwherep9T)aarepositive,gEC(R ,R)andA7g(t)=oo,andfeC(R xR',R).WeshallassumethatthereexistsafunctionF(t,u,v)6C(R;,R )suchthatFisnondecreasinginuandvandWeshallnotethatequationswithmaximaoccurintheproblemofautomaticregulationofvariousrealsystems[4],[6].Themaximaariseswhentheregu-lationlawcorrespondstothemaximaldeviationoftheregurablequantity.Ourmaingoalwillbetoestablishsufficientconditionsfortheexistenceofoscillatorysol… 相似文献