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1.
具非正系数的二阶中立型泛函微分方程的渐近性   总被引:1,自引:0,他引:1  
傅希林  张立琴 《应用数学》1994,7(3):343-348
本文讨论一类具非正系数的二阶中立型泛函微分方程非振动解的渐近性类型与判别,我们给出了非振动解的四种渐近性类型及其判别准则,这些判别准则都是充分必要条件。  相似文献   

2.
本文考虑二阶非线性椭圆型偏微分方程解的振动性质,得到了在具有“弱积分小”系数条件下,所有解均振动的充分准则,这些结果在很大程度上改进和推广了具有“积分小”系数的二阶常微分方程的振动结果.  相似文献   

3.
具正负系数的二阶阻尼微分方程的振动性   总被引:1,自引:0,他引:1  
研究了一类具有正负系数的二阶非线性变时滞中立型阻尼泛函微分方程的振动性,通过引入参数函数和Riccati变换,获得了该类方程振动的判别准则,这些准则改善了对方程的条件限制,所得结论推广并改进了现有文献中的一系列结果,并给出了例子用以说明本文的主要结论.  相似文献   

4.
本文简介了时滞泛函微分方程的研究现状和主要方法 ,并对一类二阶非线性时滞泛函微分方程的振动性和渐近性进行了研究 ,给出该类方程振动性的一个充分条件 .  相似文献   

5.
本文研究了一类具有正负系数的二阶非线性中立型时滞微分方程的振动问题.利用变限积分方法,获得了此类方程若干新的振动定理,结果推广和改进了最近Manojlovic等人在文献[4]中得到的结果.  相似文献   

6.
研究了一类具有正负系数和非线性中立项的二阶变时滞的非线性泛函微分方程的振动性,通过引入参数函数和Riccati变换,获得了方程振动的判别准则,这些准则改善了对方程的条件限制,所得结论推广并改进了现有文献中的一系列结果.  相似文献   

7.
汤慕忠  汤德全 《数学杂志》1995,15(4):441-448
本文讨论可化为一个“积分小”系数的二阶非线性微分方程的渐近性和振动性,得到若干充分性定理,推广和改进了文[1-4]的有关结果。  相似文献   

8.
一类二阶中立型泛函微分方程的振动性   总被引:12,自引:2,他引:10  
讨论了一类二阶中立型微分方程的振动性 ,通过引入参数函数 ,结合完全平方技术 ,给出了该类方程解振动的更为一般形式的判别准则 .  相似文献   

9.
二阶非线性中立型泛函微分方程的振动定理   总被引:2,自引:0,他引:2       下载免费PDF全文
本文研究一类具有变系数和变偏差的二阶非线性中立型微分方程,得到了这类方程的所有有界解都振动的Sharp条件,并给出了这类方程的线性化振动准则.  相似文献   

10.
杜炜 《数学季刊》2002,17(4):87-93
本文利用Riccati技巧和平均技巧,研究一类二阶非线性微分方程的振动性,得到了这类方程振动的若干新的判别准则。  相似文献   

11.
12.
张丽娜  吴建华 《数学进展》2008,37(1):115-117
One of the most fundamental problems in theoretical biology is to explain the mechanisms by which patterns and forms are created in the'living world. In his seminal paper "The Chemical Basis of Morphogenesis", Turing showed that a system of coupled reaction-diffusion equations can be used to describe patterns and forms in biological systems. However, the first experimental evidence to the Turing patterns was observed by De Kepper and her associates(1990) on the CIMA reaction in an open unstirred reactor, almost 40 years after Turing's prediction. Lengyel and Epstein characterized this famous experiment using a system of reaction-diffusion equations. The Lengyel-Epstein model is in the form as follows  相似文献   

13.
As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years (2001-2005). The main topics are: convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.  相似文献   

14.
In this paper, we study the explicit representation and convergence of (0, 1; 0)-interpolation on infinite interval, which means to determine a polynomial of degree ≤ 3n - 2 when the function values are prescribed at two set of points namely the zeros of Hn(x) and H′n(x) and the first derivatives at the zeros of H′n(x).  相似文献   

15.
Schr(o)dinger operator is a central subject in the mathematical study of quantum mechanics.Consider the Schrodinger operator H = -△ V on R, where △ = d2/dx2 and the potential function V is real valued. In Fourier analysis, it is well-known that a square integrable function admits an expansion with exponentials as eigenfunctions of -△. A natural conjecture is that an L2 function admits a similar expansion in terms of "eigenfunctions" of H, a perturbation of the Laplacian (see [7], Ch. Ⅺ and the notes), under certain condition on V.  相似文献   

16.
正Guest Editors:Hong Chen,Shanghai Jiao Tong University,Shanghai,China Guohua Wan,Shanghai Jiao Tong University,Shanghai,China David Yao,Columbia University,New York,USA Scope:Healthcare delivery worldwide has been fraught with high cost,low efficiency and poor quality of patient care service.For the field of operations research(OR),healthcare offers some of the biggest challenges as well as best opportunities in  相似文献   

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18.
In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p(R^n) into the Lebesgue space L^p with p 〈 1.  相似文献   

19.
In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.  相似文献   

20.
Due to the resolution of current laser technology, the accuracy of corneal topography as measured by the videokeratoscope is no longer adequate to provide precise enough data for refractive surgery or for the fitting of customized contact lenses. We present an algorithm for recovering corneal topography that makes use of modern differential geometric techniques and numerical descent in Sobolev spaces. We believe this algorithm may be used with the photo- and videokeratoscope to increase the accuracy of the recovered corneal topography.  相似文献   

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