%0 Journal Article
%T THE EXISTENCE OF PERIODIC SOLUTIONS FOR A KIND OF HIGH-ORDER DUFFING EQUATIONS WITH SIGN-CHANGING COEFFICIENT AHEAD OF NONLINEAR TERM<br>一类非线性项前系数可变号的高阶Duffing方程的周期解存在性问题
%A LI Xiaojing
%A LU Shiping
%A <br>李晓静
%A 鲁世平
%J 系统科学与数学
%D 2009
%I 
%X In this paper, by using the theory of Fourier series, Bernoulli number theory and continuation theorem of coincidence degree theory, we study a kind of high-order functional differential equation with a deviating argument as follows:x^{(m)}(t)+\beta (t)g(x(t-\tau(t)))=p(t). Some new results on the existence of periodic solutions are obtained. Here the sign of \beta(t) can be changed. But, the methods to estimate a priori bounds of periodic solutions are different from the corresponding ones of the past.
%K High-order
%K duffing equation
%K coincidence degree
%K periodic solution<br>高阶
%K Duffing方程
%K 重合度
%K 周期解.
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=37F46C35E03B4B86&jid=0CD45CC5E994895A7F41A783D4235EC2&aid=8991EDBCEC10CFAACAB665FB4350C5EB&yid=DE12191FBD62783C&vid=771469D9D58C34FF&iid=5D311CA918CA9A03&sid=E062BF8B95A95FD2&eid=DE3C727FE2D9509D&journal_id=1000-0577&journal_name=系统科学与数学&referenced_num=0&reference_num=12