Limit cycles and homoclinic orbits and their bifurcation of Bogdanov-Takens system

A quantitative analysis of limit cycles and homoclinic orbits, and the bifurcation curve for the Bogdanov-Takens system are discussed. The parameter incremental method for approximate analytical-expressions of these problems is given. These analytical-expressions of the limit cycle and homoclinic orbit are shown as the generalized harmonic functions by employing a time transformation. Curves of the parameters and the stability characteristic exponent of the limit cycle versus amplitude are drawn. Some of the limit cycles and homoclinic orbits phase portraits are plotted. The relationship curves of parameters μ and A with amplitude a and the bifurcation diagrams about the parameter are also given. The numerical accuracy of the calculation results is good.

Singular Homoclinic Orbits and Limit Cycles in Positive Second Order Slow-Fast Systems

In the paper we consider a wide class of slow-fast second order systems and give sufficient conditions for the existence of a singular limit cycle related to a homoclinic orbit.

BIFURCATION OF LIMIT CYCLES FROM A DOUBLE HOMOCLINIC LOOP WITH A ROUGH SADDLE

This paper concerns with the bifurcation of limit cycles from a double homoclinic loop under multiple parameter perturbations for general planar systems. The existence conditions of 4 homoclinic bifurcation curves and small and large limit cycles are especially investigated.

On the number of limit cycles in double homoclinic bifurcations

Let L be a double homoclinic loop of a Hamiltonian system on the plane. We obtain a condition under which L generates at most two large limit cycles by perturbations. We also give conditions for the existence of at most five or six limit cycles which appear near L under perturbations.

Bifurcations of Limit Cycles in a Z_4-Equivariant Quintic Planar Vector Field

In this paper, a Z4-equivariant quintic planar vector field is studied. The Hopf bifurcation method and polycycle bifurcation method are combined to study the limit cycles bifurcated from the compounded cycle with 4 hyperbolic saddle points. It is found that this special quintic planar polynomial system has at least four large limit cycles which surround all singular points. By applying the double homoclinic loops bifurcation method and Hopf bifurcation method, we conclude that 28 limit cycles with two different configurations exist in this special planar polynomial system. The results acquired in this paper are useful for studying the weakened 16th Hilbert＇s Problem.

WHAT ARE THE SEPARATRIX VALUES NAMED BY LEONTOVICH ON HOMOCLINIC BIFURCATION

For a given system, by using the Tkachev method which concerned with the proof of the stability of a multiple limit cycle, the exact computation formula of the third separatrix values named by Leontovich for the multiple limit cycle bifurcation was given, which was one of the main criterions for the number of limit cycles bifurcated from a homoclinic orbit and the stability of the homoclinic loop, and a computation formula for higher separatrix values was conjectured.

Global bifurcation of a cubic system perturbed by degree four

Using the method of multi-parameter perturbation theory and qualitative analysis,a cubic system perturbed by degree four are investigated in this paper. After systematic analysis,it is found that the studied system can have nine limit cycles with their distributions are obtained.

LIMIT CYCLES NEAR A DOUBLE HOMOCLINIC LOOP

In this article, we study the expansion of the first order Melnikov function in a near-Hamiltonian system on the plane near a double homoclinic loop. We obtain an explicit formula to compute the first four coeffcients, and then identify the method of finding at least 7 limit cycles near the double homoclinic loop using these coefficients. Finally, we present some interesting applications.

On the Bifurcations of a Hamiltonian Having Three Homoclinic Loops under Z_3 Invariant Quintic Perturbations

A cubic system having three homoclinic loops perturbed by Z3 invariant quintic polynomials is considered. By applying the qualitative method of differential equations and the numeric computing method, the Hopf bifurcation, homoclinic loop bifurcation and heteroclinic loop bifurcation of the above perturbed system are studied. It is found that the above system has at least 12 limit cycles and the distributions of limit cycles are also given.

Global Bifurcation of a Perturbed Double-Homoclinic Loop

This paper deals with a kind of fourth degree systems with perturbations. By using the method of multi-parameter perturbation theory and qualitative analysis, it is proved that the system can have six limit cycles.

On the limit cycles of a quintic planar vector field

This paper concerns the number and distributions of limit cycles in a Z 2-equivariant quintic planar vector field. 25 limit cycles are found in this special planar polynomial system and four different configurations of these limit cycles are also given by using the methods of the bifurcation theory and the qualitative analysis of the differential equation. It can be concluded that H(5) ? 25 = 52, where H(5) is the Hilbert number for quintic polynomial systems. The results obtained are useful to study the weakened 16th Hilbert problem.

THE POINCAR BIFURCATION OF A CUBIC HAMILTONIAN SYSTEM WITH HOMOCLINIC LOOP

In this paper, we discuss the Poincare bifurcation of a cubic Hamiltonian system with homoclinic loop. We prove that the system can generate at most seven limit cycles after a small perturbation of general cubic polynomials.

BIFURCATION OF CUBIC INTEGRABLE SYSTEM UNDER CUBIC PERTURBATION

In this paper, we consider the bifurcation for a class of cubic integrable system under cubic perturbation. Using bifurcation theory and qualitative analysis, we obtain a complete bifurcation diagram of the system in a neighbourhood of the origin for parameter plane.

The Global Bifurcation of a Cubic System

In this paper, we study the perturbation of certain of cubic system. By using the method of multi-parameter perturbation theory and qualitative analysis, we infer that the system under consideration can have five limit cycles.

Bogdanov-Takens Bifurcation in a Leslie-Gower Predator-prey Model with Prey Harvesting

This paper discuss the cusp bifurcation of codimension 2 （i.e. Bogdanov-Takens bifurcation） in a Leslie^Gower predator-prey model with prey harvesting, which was not revealed by Zhu and Lan [Phase portraits, Hopf bifurcation and limit cycles of Leslie-Gower predator-prey systems with harvesting rates, Discrete and Continuous Dynamical Systems Series B. 14（1） （2010）, 289-306]. It is shown that there are different parameter values for which the model has a limit cycle or a homoclinic loop.

On Canard Homoclinic of a Liénard Perturbation System

The classification on the orbits of some Liénard perturbation system with several parameters, which is relation to the example in [1] or [2], is discussed. The conditions for the parameters in order that the system has a unique limit cycle, homoclinic orbits, canards or the unique equilibrium point is globally asymptotic stable are given. The methods in our previous papers are used for the proofs.

含参非线性扰动系统的闭轨分叉分析

研究了一类含参非线性系统的闭轨分叉问题,找到并确定了系统在平衡点附近的极限环及其稳定性.基于后继函数法,引入曲线坐标变换找到系统的后继函数,进而判断该闭轨为二重极限环.得到该系统极限环随参数变化从无到有,再到分裂为多个极限环的闭轨分叉现象.通过数值模拟,验证了系统随参数变化出现极限环的动力学特性.

一类被开发的捕食-食饵系统的定性分析

讨论了一类食饵种群被开发的两种群捕食系统,主要讨论了系统平衡点的行为以及系统的全局稳定性。用P ioncare切性曲线法及Du lac函数法得到了闭轨不存在的充分条件。用Hop f分支理论及张芷芬唯一性定理证明了极限环的存在唯一性。

近哈密顿系统极限环的Hopf分支与同宿分支

利用Hopf与同宿两种分支中出现的系数研究了近哈密顿系统Hopf和同宿分支产生的极限环的个数与分布,得到了全局分支产生极限环的一个新的充分条件.

一类三次系统的极限环与分支问题

讨论了E31系统中一类属于广义Liénard型方程x。+f1(x)x。+f2(x)x。2+g(x)=0的系统x。=yy。=-x+δy+nx2+mxy+ly2+bxy2在m,n,l同号及b≠0情况下的极限环的存在惟一性与分支问题.