极限环

The critical value of Hopf bifurcation was calculated, and the stability of the limit cycle was discussed. The bifurcation diagram of the system was obtained by the fourth order Runge-Kutta method.

定性分析了系统定态的存在性和稳定性，讨论了系统的Hopf分岔，得到了系统的Hopf分岔参数值，并判断了极限环的稳定性。

In the second chapter, we consider a kind of Kolmogorov system. The sufficient conditions of nonexistence of the closed orbit and existence of the unique and stable limit cycle are obtained.

第二章讨论了一类Kolmogorov系统，得到了系统无闭轨的充分条件和存在唯一稳定极限环的条件，推广了颜向平，张存华等的结果。

It is found that the frequency creep caused by superradiance usually results in this kind of limit cycle like oscillations.

分析表明这种类极限环振荡主要起因于超辐射引起的频率蠕变。

In the second chapter, we deal with the global of systemBy virtue of the abundant results of Lienard equation, integrated with the theory of rotated vector field, we discussed of the number and distribution of limit cycles of the system and obtain its global structure.

第二章讨论了系统的全局结构。利用定性理论中关于Liénard型方程已有的丰富结果及旋转向量场理论讨论了极限环的个数及其相对位置，得到了系统的全局结构。第三章讨论了系统的局部分支。

Utilizing the theory of Lur\'e system,the paper studies the practical synchronization of the system composed by nonidentical cells coupled through quorum sensing.This type of synchronization,which implies the dynamics of each cell is similar but with small difference,is a common kind of phenomenon.

本文利用相约化方法将振子网络的状态方程转化为相应的相方程，然后通过对其相方程进行分析，证明了耦合极限环振子网络在很弱的平衡耦合下就可以实现相同步。

Firstly, for the network with arbitrary weight matrix, the conditions for the existence of cycle of length 1 and 2 are presented.

首先，对于具有任意连接权阵的网络，给出了不动点和2周期极限环存在的条件。

The existence of limit cycles for nonlinear equation are discussed.

讨论了更一般非线性方程的极限环的存在性。

The describing function technique is mainly employed to predict the existence of constant amplitude oscillations of closed nonlinear systems and has been successfully used in many applications.

利用描述函数法将非线性元件线性化，以预测其极限环的发生，已成功的使用在许多的应用上。

Considering a predator-prey system with a kind functional reaction in which the predator species have no density restriction,no fishing,while the prey species have nonlinear density restriction and the constant invest.

考虑捕食者无密度制约、无捕捞，而食饵具有非线性密度制约和常投放率的一类功能性反应的食饵捕食系统，对其进行了定性分析，证明了在不稳定的正平衡点附近存在唯一的极限环。

In the system of high precision and low speed, Because of the existence of the nonlinear friction, the static and dynamic performance of the servo system is very bad, such as stick slip, hunting, large error and so on, Because the traditional control of PID is hard to solve the nonlinear problem of the servo system, so this paper begins to introduce a new control method which is named adaptive fuzzy PID, It utilizes the rule of the fuzzy control to adjust the parameter of proportion, integral and differential on line, So this control method has some intelligence to improve the static and dynamic performance of the servo system.

在高精度、超低速伺服系统中，由于非线性摩擦环节的存在，使系统的动态及静态性能受到很大程度的影响，主要表现为低速时出现爬行现象，稳态时有较大的静差或出现极限环振荡；由于传统的PID 控制很难解决伺服系统中的非线性问题，因而不能适用于高精度、超低速伺服系统；本文通过引入模糊自适应整定PID控制，利用模糊规则在线调整比例、积分、微分环节，使系统具有一定的智能，从而非常明显的改善伺服系统的静态及动态性能。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。