Analytical Conditions for the Existence of a Homoclinic Loop in Chua Circuits

We analyze a third-order piecewise-linear system that describes the operation of an electronicoscillator. This system can be used to investigate various scenarios for the onset of chaos, in particular, through separatrix loop destruction. Necessary and sufficient conditions are obtained for the existence of an equilibrium separatrix loop. Calculation of critical parameters is illustrated.     

Unfolding of a Quadratic Integrable System with a Homoclinic Loop

In this paper, we make a complete study of the unfolding of a quadratic integrable system with a homoclinic loop. Making a Poincaré transformation and using some new techniques to estimate the number of zeros of Abelian integrals, we obtain the complete bifurcation diagram and all phase portraits of systems corresponding to different regions in the parameter space. In particular, we prove that two is the maximal number of limit cycles bifurcation from the system under quadratic non-conservative perturbations. Received July 16, 1999, Revised March 15, 2001, Accepted May 25, 2001     

一类非线性离散系统的同宿解的存在性

应用临界点理论讨论一类二阶非线性离散系统在一定条件下非零同宿解的存在性,得到一个非零同宿解存在性的条件.     

Existence of Solutions for Semilinear Nonlocal Elliptic Problems via a Bolzano Theorem

In this paper we deal with the existence of positive solutions for the following nonlocal type of problems $$\everymath{\displaystyle} \left\{ \begin{array}{l@{\quad}l} -\Delta u = \frac{\sigma}{( \int_{\varOmega} g(u)\, dx )^p} f(u) & \mbox{in}\ \varOmega, \\[3mm] u>0 & \mbox{in}\ \varOmega, \\[1mm] u=0 & \mbox{on}\ \partial\varOmega, \end{array} \right. $$ where Ω is a bounded smooth domain in ? ^N (N≥1), f,g are continuous positive functions, σ>0 and p∈?. We give sufficient conditions on the functions f and g in order to have existence of positive solutions.     

具有非局部源的退化半线性抛物型方程组解的爆破

本文讨论具有非局部源退化半线性抛物型方程组的初边值问题 .证明了局部解的存在唯一性并且得到当初值充分大时解在有限时刻爆破 .     

一类非线性系统同宿轨族的存在性

本文研究非线性系统x=（h（y）－F（x））y＝－g（X）的同宿轨族问题，获得此系统存在同宿轨族的充要条件及同宿轨与闭轨同时存在的充分条件．     

具非局部源项的抛物系统解的整体存在与爆破(英文)

考虑一个具有非局部源项的抛物系统非负解的整体存在与爆破问题,通过使用上下解技术,建立了系统的临界指数,而且,相关的分类是最优与最完全的.     

一类非自治p-Laplace系统的同宿轨道

利用临界点理论的极小化原理讨论一类非自治p-L ap lace系统d/(dt)(q(t)p-2q(t))-l(t)q(t)p-2q(t)+▽W(t,q(t))=0非平凡同宿轨道的存在性,其中,p>1,t∈R,q∈Rn,l:R→(0,+∞),W(t,q(t))=a(t)q(t)γ且a(t):R→R+是一非负连续函数,1<γ相似文献   

一个局部波动方程组的解的全局存在性与爆破

我们研究初始值问题(e)u1/(e)t2=(e)2u1/(e)x2+‖u2(·,t)‖p, (e)2u2/(e)t2=(e)2u2/(e)x2+‖u1(·,t)‖q,-∞<x<∞,t>0,u1(x,0)=f1(x), (e)u1/(e)t(x,0)=g1(x),u2(x,0)=f2(x), (e)u2/(e)t(x,0)=g2(x),- ∞<x<∞,where‖ui(·,t)‖=∫∞-∞(4)i(x)|ui(x,t)|dx with (4)i(x)≥0 and ∫∞-∞(4)i(x)dx=1,i=1,2.然后建立解的全局存在和爆破的标准,提出爆破增长率.     

On Hamiltonian Systems with a Homoclinic Orbit to a Saddle-Center

We consider a real analytic Hamiltonian system with two degrees of freedom having a homoclinic orbit to a saddle-center equilibrium (two nonzero real and two nonzero imaginary eigenvalues). We take a two-parameter unfolding for such a system and show that in the nonresonance case, there are countable sets of multi-round homoclinic orbits to a saddle-center. We also find families of periodic orbits accumulating at homoclinic orbits. Bibliography: 6 titles.__________Published in Zapiski Nauchnykh Seminarov POMI, Vol. 300, 2003, pp. 187–193.     

含各阶导数的非线性弹性梁方程的一个存在定理

通过选择适当的Banach空间并利用Leray-Schauder非线性抉择对于含各阶导数的非线性弹性梁方程{u(4)(t)=f(t,u(t),u′(t),u″(t),u′″(t)),0≤t≤1, u(0)=u′(1)=u″(0)=u′″(1)=0.建立了一个解的存在定理．在材料力学中，该方程描述了一端简单支撑，另一端被滑动夹子夹住的弹性梁的形变．这个存在定理说明只要非线性项满足某种线性增长条件该方程至少有一个解．     

An Extension of Weyl Schouten Theorem for Lipschitz and H~2 Manifolds

In this article,we extend the Weyl Schouten Theorem for a C~(0,1)∩ W~(2,2) manifold only under the assumptions on scalar curvature. Also we obtain a regularity of a C~(0,1)∩W~(2,2) manifold by conformal transformation under some assumptions on Weyl curvature and scalar curvature.     

非线性弹性梁方程的一个孪生正解的存在定理

对于非线性四阶两点边值问题建立了一个孪生正解的存在定理．该边值问题通常描述了具有固定两端点的弹性梁的形变．     

一类二阶微分方程同宿解的存在性

讨论下列二阶微分方程(y|¨)+ay+U_y(t,y)=0.的同宿解的存在性,其中t∈R,y∈Rⁿ,n∈N,a>0是一个常数,U(t,y)∈Cn,n∈N,a>0是一个常数,U(t,y)∈C¹(R×R1(R×Rⁿ,R),U_y(t,y)表示U(t,y)关于y的梯度.引入快同宿解的概念并给出方程存在快同宿解的判定准则.     

Multiple of Homoclinic Solutions for a Perturbed Dynamical Systems with Combined Nonlinearities

In this paper, we study the existence of multiple and infinite homoclinic solutions for the following perturbed dynamical systems

$$\begin{aligned} \ddot{x}+A\cdot \dot{x}-L(t)\cdot x+\nabla W(t,x)=f(t), \end{aligned}$$

where \(t\in {\mathbb R}, x\in {\mathbb R}^N,\) A is an antisymmetric constant matrix, the matrix L(t) is not necessary positive definite for all \(t\in {\mathbb R}\) nor coercive, the nonlinearity \(W \in C^{1}(\mathbb {R}\times \mathbb {R}^{N},\mathbb {R})\) involves a combination of superquadratic and subquadratic terms and is allowed to be sign-changing and \(f\in C({\mathbb R},{\mathbb R}^{N})\cap L^{2}({\mathbb R},{\mathbb R}^{N}).\) Recent results in the literature are generalized and significantly improved and some examples are also given to illustrate our main theoretical results.

     

奇异三阶两点边值问题解的一个存在定理

By constructing suitable Banach space.an existence theorem is established under a condition of linear growth for the third-order boundary value problem u'(t) f(t,u(t),t'(t),u(t))=0,0＜t＜1,u(0)=u'(0)=u'(1)=0,where the nonlinear term contains first and second derivatives of unknown function.In this theorem the nonlinear term f(t,u,v,w)may be singular at t=0 and t=1.The main ingredient is Leray-Schauder nonlinear alternative.     

超线性半正二阶三点边值问题的一个正解存在定理

建立了超线性二阶三个边值问题的一个正解存在定理。这里，非线性项是下有界的并且不需要是非负的。     

Existence of Solutions for a Class of Nonlinear Evolution Inclusions with Nonlocal Conditions

This paper deals with the nonlocal problems for a class of nonlinear first-order evolution inclusions. Some existence results are established for the cases of a convex and of a nonconvex valued perturbation terms. Also, the existence of extremal solutions and a strong relaxation theorem are obtained. Subsequently a nonlinear hyperbolic optimal control problem is considered and the existence theorems based on the proven results are obtained. Then the nonlinear version of “bang–bang” principle for control systems is given as well by utilizing the relaxation theorem.