高阶非线性差分方程的振动性

本文研究了差分方程△ｄｘ（ｎ）＋ｐ（ｎ）△（ｄ－１）ｘ（ｎ）＋Ｈ（ｎ，ｘ（ｎ））＝０，（１．１）△ｄｘ（ｎ）＋ｐ（ｎ）△（ｄ－１）ｘ（ｎ，ｘ（ｎ））＝Ｑ（ｎ）．（１．２）在一定的条件下，证明了方程（１．１）与（１．２）在振动性方面的等价问题．对于方程（１．１）或（１．２），在ｎ是偶数时的每一个有界解是振动的，在ｎ是奇数时，每一个有界解是振动的或当→∞时单调趋于零的充要性定理也建立了．     

OSCILLATION CONVERGENT THEOREMS FOR THE V^2-INTEGRAL

The V^t-integral as defined in[2], which is eqnivalent to M^2-integrsl as defined in Trigonometre series by Zygmund is used to sum trigonometric seies in[1]. In this paper, some convergent theorems of V^2-integral are established.     

关于Hunt－Yorke猜想的证明

考虑具有ｎ个变时滞的泛函微分方程其中ｑ＿ｉ（ｔ），Ｔ＿ｉ（ｔ）∈Ｃ（［０，＋∞），Ｒ￣＋），ｉ＝１，２，…，ｎ。本文证明了Ｈｕｎｔ－Ｙｏｒｋｅ猜想；同时还得到了在Ｋｗｏｎｇ－Ｐａｔｕｌａ意义下泛函微分方程强振动的充分条件。     

Finite Integral Transform Solutions for Free Vibrations of Rectangular Thin Plates With Mixed Boundary Constraints北大核心CSCD

Analytical solutions, with unique research value, can serve as benchmarks for empirical formulas and numerical methods, a tool for rapid parameter analysis and optimization, and a theoretical basis for experimental designs. Conventional analytical methods, e.g., the Lévy solution method, are only applicable to mechanical problems of plates and shells with opposite simply-supported edges, which, however, may fail to obtain analytical solutions for the issues with complex boundary constraints. In recent years, the finite integral transform method for plate and shell problems was developed to deal with non-Lévy-type plates and shells, but it is still infeasible to solve the mixed boundary constrains-induced complex boundary value problems of higher-order partial differential equations. Herein, for the first time, the finite integral transform method was combined with the sub-domain decomposition technique to solve the free vibrations of rectangular thin plates with mixed boundary constraints. The rectangular plate was first divided into 2 sub-domains according to the mixed boundary constraints, and the 2 sub-domains were solved analytically with the finite integral transform method. Finally, the continuity conditions were introduced to obtain the analytical solution of the original problem. Based on the side spot-welded cantilever plates commonly used in engineering, the free vibration problem of a rectangular thin plate with 1 edge subjected to clamped-simply supported constraints and the other 3 edges free, was analyzed. The obtained natural frequencies and mode shapes are in good agreement with those from the finite element method as well as the solutions in literature, thus verifying the accuracy of the proposed method. The solution procedure of the finite integral transform method can be implemented based on the governing equations without any assumption of the solution form. Therefore, this strict analytical method is widely applicable to complex boundary value problems of higher-order partial differential equations for such mechanical problems of plates and shells. © 2023 Editorial Office of Applied Mathematics and Mechanics. All rights reserved.     

挖坑机钻头主轴纵向振动系统模型的建立与控制

首先利用弹性杆理论和H am ilton变分原理建立了挖坑机钻头主轴及钻尖在工作过程中由于外激励的作用使钻尖与土壤互相作用而产生纵向振动的动力学模型,同时给出边界条件和初始条件.其次通过把系统外激励函数当作控制变量,利用Banach空间几何性质证明了此系统存在唯一最优控制元.     

一类脉冲中立型时滞抛物方程组的振动性

研究一类脉冲中立型时滞抛物方程组解的振动性,得到了该类方程组在两类不同边界条件下所有解振动的若干充分条件.     

高振动积分的一种新的有效Levin-type配置法

本文给出了高振动积分的一种新的有效Levin-type配置法, 并对它的有效性和精度进行了检验, 与Levin配置法相比较, 这种方法具有更高的精度而且容易实现.     

带强迫项的高阶中立型时滞差分方程的振动定理

本文研究带有强迫项的高阶中立型时滞差分方程的振动性.我们建立了方程(E)的新的振动准则且给出了说明定理应用的例子.     

中立型时滞差分方程的振性与正解存在性

本文研究了一类中立型时滞差分方程的振动性和正解存在性，获得了该方程所有解振动的“Sharp”条件及存在正解的一个充分条件．