On asymptotic behaviors of solutions of “almost linear” and essential nonlinear functional differential equations

In the paper the following differential equation

(0.1)     

一类中立型双曲微分方程的振动性定理

本文运用Philos方法,获得了一类具连续偏差变元的中立型双曲微分方程的振动性的充分性条件.     

On the structure of positive solutions of a class of fourth order nonlinear differential equations

A detailed analysis is made of the structure of positive solutions of fourth-order differential equations of the form

Relative oscillation theory for Dirac operators

We develop relative oscillation theory for one-dimensional Dirac operators which, rather than measuring the spectrum of one single operator, measures the difference between the spectra of two different operators. This is done by replacing zeros of solutions of one operator by weighted zeros of Wronskians of solutions of two different operators. In particular, we show that a Sturm-type comparison theorem still holds in this situation and demonstrate how this can be used to investigate the number of eigenvalues in essential spectral gaps. Furthermore, the connection with Krein's spectral shift function is established. As an application we extend a result by K.M. Schmidt on the finiteness/infiniteness of the number of eigenvalues in essential spectral gaps of perturbed periodic Dirac operators.     

Remarks on the paper [Appl. Math. Comput. 207 (2009) 388-396]

In this paper, some sufficient conditions are established for the oscillation of second-order neutral differential equations

     

带阻尼项的非线性矩阵微分系统的振动性

通过定义新的预备解及利用矩阵Riccati技巧、平均技巧及矩阵不等式,给出了带阻尼项的二阶非线性矩阵微分系统(P(t)X′(t))′+R(t)X′(t)+Q(t)F(X′(t))G(X(t))=0的一些振动性准则;所得结果推广和改进了已有文献的相关结果。     

中立型时滞逻辑斯谛方程无界正解的振动性

关于中立型逻辑斯谛方程有界正解的研究已有了长足的发展,而无界正解的研究在已有文献中却非常少见。本文利用振动性原理,结合分析方法得到其无界正解的渐近行为,由此建立中立型时滞逻辑斯谛方程无界正解振动的充分与必要条件,所获结果推广了相关文献的结论。     

Renormalized oscillation theory for Dirac operators

Oscillation theory for one-dimensional Dirac operators with separated boundary conditions is investigated. Our main theorem reads: If and if solve the Dirac equation , (in the weak sense) and respectively satisfy the boundary condition on the left/right, then the dimension of the spectral projection equals the number of zeros of the Wronskian of and . As an application we establish finiteness of the number of eigenvalues in essential spectral gaps of perturbed periodic Dirac operators.

     

具连续变量的线性时滞差分方程的振动性

本文研究如下具有连续变量的线性时滞差分方程ｙ（ｔ）－ｙ（ｔ－τ）＋∑ｍｊ＝１ｐｊ（ｔ）ｙ（ｔ－σｊ）＝０,ｔ≥０,其中ｐｊ（ｔ）∈ｃ（Ｒ＾＋,Ｒ＾＋）,０〈τ〈σ１≤σ２≤…≤ｍ,ｊ＝１,２,…,ｍ,获得了该方程的每个解都振动的若干充分条件,改进了现有文献中的结果。