求余摆线与圆的交点的一种逼近方法

余摆线是农机具运动学研究及设计中常见的曲线之一.如拨禾轮式收割机、滚直插式插秧机、刨埯机等,都采用如下的机制进行作业:工作部件(如拨禾轮、分插轮等)在随机具以匀速 v 作水平运动的同时,又以匀角速ω绕其轴心旋转(图1).根据作业要求,一般取     

具有双参数的培养器系统的Hopf分支

We study a chemostat system with two parameters, So-initial density and D-flow-speed of the solution. At first, a generalization of the traditional Hopf bifurcation theorem is given. Then, an existence theorem for the Hopf bifurcation of the chemostat system is presented.     

Φилиппов定理的推广

This paper generalizes Filippov' s Theorem which is considered to be one of the most representive theorems dealing with the existence of the limit cycles of Lienard' s equaton.     

RESEARCH ANNOUNCEMENTS —— On the conditions for the Orbitally Asymptot

This paper studies the behaviors of the solutions in the vicinity of a givenalmost periodic solution of the autonomous system x′=f(x), x Rn , (1) where f C1 (Rn ,Rn ). Since the periodic solutions of the autonomous system are not Liapunov asymptotic stable, we consider the weak orbitally stability. 　　For the planar autonomous systems (n=2), the classical result of orbitally stability about its periodic solution with period w belongs to Poincare, i.e.     

ON THE EXISTENCE OF PERIODIC SOLUTIONS OF NONLINEAR OSCILLATION EQUATIONS

This paper deals with the existence of periodic solutions of the nonlinear oscillationequation f(x)(x) ψ(x)η(x)=0.The author offers a method which can reduce(3)into the system=h(y)-e(y)F(x),=-g(x).(9)Some sufficient conditions for the existence of the limit cycles of(9)are obtained.These results generalize the results in [1,2,3,4,5,6](3)(9)obfained.     

一类二阶常微分方程组解的全局渐近性态

<正> 的解的全局渐近性态,然后把所得结果应用到某些二阶非线性常微分方程式上去.近年来,在二阶非线性常微分方程式的全局稳定性方面做出较好的工作的有何崇佑,周毓荣及 T.A.Burton 等人.本文的结果是对他们的工作的补充.     

海绵Callyspongia Fibrosa的化学成分研究(Ⅰ)

从中国南海海绵中分离鉴定出 5个化合物 ,其结构确定为对羟基苯甲酸 ( Ⅰ)、鲨肝醇 ( Ⅱ )、胸腺嘧啶( Ⅲ )、尿嘧啶 ( Ⅳ )、胸腺嘧啶脱氧核苷 (Ⅴ )。     

(?)илиппов定理的推广

在文[1]中(或参看[2][3][4])提出的关于Liénard方程 或其等价方程组 (F(x)=integral from n=0 to x (f(ξ)dξ)) 的极限环的存在性的定理,至今仍是条件最少的。本文利用李雅普诺夫函数的方法推广了这个定理。     

具无限时滞的泛函微分方程的周期解的存在性

具无限时滞的泛函微分方程的周期解的存在性问题,是有关学者近年来极为关心的一个问题。本文综合应用Liapunov直接法、比较定理以及泛函方法,证明了两条一般性定理。并且将它们应用到Volterra积分微分方程上去,获得相当简洁的结果。     

RESEARCH ANNOUNCEMENTS:On the Conditions for the OrbitallyAsymptotical Stability of the AlmostPeriodic Orbits of Dynamical Systems

This paper studies the behaviors of the solutions in the vicinity of a given almost periodicsolution of the autonomous systemwhere f ∈E C1(Rn, Rn). Since the periodic solutions of the autonomous system are not Liapunovasymptotic stable, we consider the weak orbitally stability.For the planar autonomous systems (n=2), the classical result of orbitally stability aboutits periodic solution with period w belongs to Poincare, i.e.Theorem A[1,2] A periodic solution p(t) to (1) with period w is o…