共查询到20条相似文献,搜索用时 9 毫秒
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Asymptotic formulas, as ɛ→ 0+ , are derived for the solutions of the nonlinear differential equation ɛ u" + Q ( u ) = 0 with boundary conditions u (-1) = u (1) = 0 or u '(-1) = u '(1) = 0 . The nonlinear term Q ( u ) behaves like a cubic; it vanishes at s - , 0, s + and nowhere else in [ s - , s + ] , where s - < 0 < s + . Furthermore, Q '( s ± ) < 0, Q '(0) > 0 and the integral of Q on the interval [ s - , s + ] is zero. Solutions to these boundary-value problems are shown to exhibit internal shock layers, and the error terms in the asymptotic approximations are demonstrated to be exponentially small. Estimates are obtained for the number of internal shocks that a solution can have, and the total numbers of solutions to these problems are also given. All results here are established rigorously in the mathematical sense. 相似文献
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Carrier and Pearson introduced a nonlinear singularly perturbed boundary value problem that has served as a paradigm for problems where the method of matched asymptotic expansions (MAE) apparently fails. The “failure” of MAE is its inability to select the location of possible internal layers, though their structure is determined. Thus, a straightforward application of MAE leaves the positions of any internal layers arbitrary, though the asymptotic expansion of the exact solution to the problem exhibits internal layers only at specific locations. For this reason the solutions produced by MAE have been referred to as spurious solutions. We resolve the question of finding the positions of the interior layers by employing the variational approach of Grasman and Matkowsky. In addition, we show that this method tells how solutions bifurcate as the boundary values are varied, and give an alternative motivation for the variational approach via Newton”s method. 相似文献
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莫嘉琪 《数学物理学报(A辑)》2003,23(3):374-378
研究了具有非线性反应扩散方程奇摄动问题。在适当的条件下,利用微分不等式理论,讨论了当退化问题具有两个相交解时,原初始边值问题解的渐近性态。
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本文讨论了一类具有奇性方程的奇摄动初值问题.在适当条件下,利用微分不等式理论,研究了初值问题解的存在性及其渐近性态,并且得到了具有初始层的一致有效解的渐近展开式. 相似文献
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Ukrainian Mathematical Journal - We study the asymptotic behavior of the solutions of a boundary-value problem with boundary jumps for linear integrodifferential equations of the third order with... 相似文献
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ZHANG Han-lin 《数学季刊》2005,20(4):385-389
A class of singularly perturbed problems for the nonlinear elliptic equations is considered. Under suitable conditions, using the theory of differential inequalities the asymptotic behavior of solution for the boundary value problems are studied, which reduced equations possess two intersecting solutions. 相似文献
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非线性非局部反应扩散方程奇摄动问题 总被引:1,自引:1,他引:1
研究了一类具有非线性非局部反应扩散方程奇摄动Robin初始边值问题。在适当的条件下,首先求出了原问题的外部解,然后利用伸长变量、合成展开法和幂级数展开理论构造出解的初始层项,并由此得到解的形式渐近展开式。最后利用微分不等式理论,讨论了问题解的渐近性态并导出了几个有关的不等式,讨论了原问题解的存在唯一性和解的一致有效的渐近估计式。 相似文献
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一类非线性奇摄动方程的激波问题 总被引:4,自引:1,他引:3
利用奇摄动理论和匹配原理,讨论了一类非线性奇摄动方程的激波问题.首先,构造了原问题的外部解和内层解.其次,研究了当激波在区间的边界附近和内部的激波解.最后,得出了与边界条件相对应的激波位置及解的表达式. 相似文献
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研究了具有边界摄动的非线性反应扩散方程奇摄动问题.在适当的条件下,利用微分不等式理论,讨论了问题解的渐近性态. 相似文献
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本文研究一类非线性时滞微分方程边值问题在条件fy≤-m<0下,利用微分不等式理论证明了边值问题解的存在性,并给出了解的一致有效渐近展开式. 相似文献
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The nonlinear singularly perturbed problems for elliptic equations with boundary perturbation are considered. Under suitable conditions, by using the theory of differential inequalities the asymptotic behavior of solutions for the boundary value problems is studied. 相似文献
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讨论了一类具有超抛物型方程的反应扩散问题.首先,证明了比较定理.其次,构造了形式渐近解.然后,利用微分不等式方法,研究了问题解的存在、唯一性和渐近性态.最后得到了原问题解的渐近展开式. 相似文献
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§ 1 . Introduction AclassofintegraldifferentialequationsDirichletboundaryvalueproblemsforordinarydif ferentialequationandellipticequationarediscussedin [1]and [2 ]respectively .Andin [3]akindofnonlocalproblemsforsingularlyperturbedreactiondiffusionsystemsarestudied.Inthispaper,whatisworthpointingoutisaclassofnonlinearboundaryvalueproblemsdiscussed,applyingthemethodofcompositeexpandandthetheoryofdifferentialinequalities.εy″ =f(x ,y ,Tεy ,ε) y′ +g(x ,y ,Tεy,ε) ,0 相似文献
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一类具有边界摄动的非线性泛函椭圆型方程奇摄动问题 总被引:1,自引:0,他引:1
研究了具有边界摄动的非线性泛函椭圆型方程奇摄动边值问题.在适当的条件下.利用伸长变量、微分不等式理论,讨论了问题解的渐近性态和原问题解的存在唯一性。 相似文献
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具有转向点的积分微分方程奇摄动非线性边值问题 总被引:5,自引:0,他引:5
对一类具有转向点的Volterra型积分微分程奇摄动非线性边值问题证明了解的存在性并给出了解的一致有效渐近估计. 相似文献
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奇摄动非线性边值问题 总被引:5,自引:0,他引:5
本文讨论了一类奇摄动非线性边值问题 .利用伸长变量和边界层校正法 ,得到了问题解的形式渐近展开式 .再用微分不等式理论 ,证明了解的一致有效性 相似文献
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A class of nonlinear nonlocal singularly perturbed Robin initial boundary value problems for reaction diffusion equations with boundary perturbation is considered. Under suitable conditions, firstly, the outer solution of the original problem is obtained; secondly, by using the stretched variable, the composing expansion method and the expanding theory of power series, the initial layer is constructed; and finally, by using the theory of differential inequalities the asymptotic behavior of solutions for initial boundary value problems is studied, and including some relational inequalities the existence and uniqueness of solutions for the original problem and the uniformly valid asymptotic estimation are discussed. 相似文献