共查询到19条相似文献,搜索用时 252 毫秒
1.
研究时滞Li啨nard方程¨x+f1(x)·x+f2(x(t-τ))·x(t-τ)+g(x(t-τ))=e(t)的解的有界性,其中f1,f2均连续可微,g(t)可微,e(t)为连续函数,当f2=0时,上方程就化为文献[9]中研究的方程¨x+f(x)·x+g(x(t-τ))=e(t).结果推广了文献[9]中的结论. 相似文献
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次线性条件下,脉冲系统x"+f(t,x)=0,a.e.t∈[0,2π]Δx'(t_j):=x'(t+j)-x'(t_j~-)=I_j(x(t_j))j=1,2,…,p的周期解的存在性被广泛研究.这里的次线性主要体现在f(t,x)被下面次线性函数控制:|f(t,x)|≤g(t)|x|α+h(t)其中g,h∈L~1(0,2π;R~+),α∈[0,1).本文减弱了上述次线性控制的要求,利用临界点理论证明了当f(t,x)满足某个函数类条件时,脉冲方程周期解是存在的,从而推广了相关结果. 相似文献
4.
本文给出了方程 [(a(t)x′)′+h(t,x,x′)x′+q(t)f(x)g(x′)=e(t,x,x′)的解的有界性和渐近稳定性的充分条件,所得结果改进和包含了一些已知的结果。 相似文献
5.
给出了带强迫项的二阶非线性微分方程x″(t)+p(t)f(x(t),x(τ(t)))g(x′(t))=e(t)振动的若干新的充分条件,改进并推广了孙元功(2003)的结果. 相似文献
6.
研究了一类二阶微分方程x″+f(x)x′+g(x)=e(t)调和解的存在性.假设f(x)有界,g(X)满足新的单侧条件,即当x≥d时g(x)/x≥a,以及当x<d时g(x)满足次线性条件或者有界,应用连续引理,得到了调和解的存在性定理. 相似文献
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假设(Xt,Px)是与L2(E;m)上的半狄氏型((e),D((e)))相联系的右过程.μ为符号光滑测度,Aμt为μ对应的连续可加泛函.定义广义Feynman-Kac半群Pμtf(x)∶=Ex[e-tf(Xt)].设(e)μ(f,g)=(e)f,g)+(f,g)μ,(V)f,g∈D((e)μ)=D((e))∩L2(E,|μ|),我们得到以下两个命题等价:①((e)μ,D((e)μ))是下半有界的;②对任意的t>0,存在一个常数α0≥0使得||Pμt|2≤eα0t.如果①和②中有一个成立,则(Pμt)t≥0是L2(E;m)上强连续的半群. 相似文献
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《四川师范大学学报(自然科学版)》2016,(1)
利用Mawhin延拓定理证明,构造新算子,使用新技巧,研究了一类具有强迫项和有限时滞的二阶Lienard方程x″(t)+f1(x)x'(t)+f2(x)(x'(t))2+g(x(t-τ))=e(t)的周期解问题,得到了方程至少存在一个周期解的充分条件,获得了新的结论. 相似文献
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考虑未扰Liénard系统ẋ=y,ẏ=-g(x),其中deg g(x)=7,当该系统分别含有2,3,4和5个奇点时,给出了其所有的不同拓扑类型的相图,并给出了Melnikov函数在含有2个幂零尖点和1个双曲鞍点的双异宿环附近的展开式和得到极限环的条件. 相似文献
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利用Schauder不动点定理讨论n阶非线性泛函微分方程x ̄(n)(t)+p(t)f(x(g(t)=r(t)正解全体的构成与正解的存在性. 相似文献
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The paper is concerned with some chemotaxis model ∂u/∂t=D▿(u▿ln(u/w))+u(a−bu),∂w/∂t=f(u,w). To study the behavior of the solution, some function transformations are introduced, and the main tool is sup-sub-solution
method. The result shows that, whether the solution blows up in finite time depends on the parameters and the initial data.
As the chemical substance w has linear growth, f(u,w)=βu−δw, where β>0, δ>0 and a+δ>0, wherein the solution exists globally. However, as w possesses exponential growth, f(u,w)=(βu−δ)w, wherein both u and w share the same blowup point and time if the solution blows up in finite time.
Biography: CHEN Hua(1956–), male, Professor, Ph. D., research direction: partial differential equation and its application. 相似文献
14.
The distribution of a CP-asymmetric quantityA in the decay channelJ/ψ→π
+
π
−
π
0 is investigated. This dimensionless quantityA is constructed from the momenta of the π-meson final states, namely A=P
x
π
+
P
y
π
− -P
x
π
−
P
y
π
−, whereP
h,P
x
h
andP
y
h
are the module of the momentum of a hadron h, the x- and y-components of that momentum respectively, theJ/ψ particle is produced by e+ e− collision, and the direction of the momentum of e+ is taken to be the positive direction ofz axis. There would exists the violation under the combined transformation of charge conjugation and space reflection (CP violation)
when the average ofA among a lot of events, 〈A〉, be examined to be nonzero clearly from data. In this way, 748 events are selected from the BES experimental data, and analyzed.
The corresponding averageA-value is measured to be 〈A〉 = 0.010 39 ± 0.014 61 ± 0.015 2. Further, some discussion of our result, the size of the data sample being need for further
attempt and a possible perspective are given. 相似文献
15.
The distribution of a CP-asymmetric quantityA in the decay channelJ/ψ→π
+
π
−
π
0 is investigated. This dimensionless quantityA is constructed from the momenta of the π-meson final states, namely A=P
x
π
+
P
y
π
− -P
x
π
−
P
y
π
−, whereP
h,P
x
h
andP
y
h
are the module of the momentum of a hadron h, the x- and y-components of that momentum respectively, theJ/ψ particle is produced by e+ e− collision, and the direction of the momentum of e+ is taken to be the positive direction ofz axis. There would exists the violation under the combined transformation of charge conjugation and space reflection (CP violation)
when the average ofA among a lot of events, 〈A〉, be examined to be nonzero clearly from data. In this way, 748 events are selected from the BES experimental data, and analyzed.
The corresponding averageA-value is measured to be 〈A〉 = 0.010 39 ± 0.014 61 ± 0.015 2. Further, some discussion of our result, the size of the data sample being need for further
attempt and a possible perspective are given. 相似文献
16.
The explicit common eigenvectors for complex scalar fields φ (x) and φ+ (x) are derived . They span an orthonormal and complete space. Based on this, the charge conjugate unitary operator and the operator which generates Bogolyubov pseudo-particles transformation can be neatly derived. It is emphasized that | ξ> is different from the direct product of two independent eigenvectors respectively belonging to two real scalar fields, and | ξ > is named the correlated eigenstates of φ( x) and φ+ (x). 相似文献
17.
基于Gaussian03计算软件,选用高角动量基函数6-311++g(df,pd),分别使用密度泛函理论UB3LYP和UB3P86,以及组态相互作用方法UCCSD-FC和UQCISD-FC,对PCl分子和PCl+,PCl-离子基态进行了几何优化,进一步对其进行了频率计算和单点能扫描计算.用最小二乘法拟合得到了PCl<em>n(n=-1,0,+1)分子离子基态的Murrell-Sorbie势能函数.与实验及理论结果比较表明,对PCl,PCl+分子离子基态光谱常数 (Be,αe,ωe,ωexe)的计算结果达到了很高的精度.文章还首次给出PCl-分子离子基态光谱参数(Be,αe,ωe,ωexe)和PCln(n=-1,0,+1)力常数(f2,f3,f4)的理论数据,为PCln(n=-1,0,+1)分子离子的更深层次研究和应用提供重要的理论基础. 相似文献
18.
Zikun Wang 《科学通报(英文版)》1999,44(5):418-418
The definition of n-parameter infinite-dimensional (r,δ) -Ornstein-Uhlenbeck process {xt (·) } ((r, δ)-OUPn∞ for short) is given. The absolute continuity of distribution μt of Xt(·) and the limit of Xt(·) when |t| →∞ is discussed. 相似文献
19.
Holub proved that any bounded linear operator T or -T defined on Banach space L 1(μ) satisfies Daugavet equation1+‖T‖=Max{‖I+T‖, ‖I-T‖}.Holub's theorem is generalized to the nonlinear case: any nonlinear Lipschitz operator f defined on Banach space l 1 satisfies1+L(f)=Max{L(I+f), L(I-f)},where L(f) is the Lipschitz constant of f. The generalized Holub theorem has important applications in characterizing the invertibility of nonlinear operator. 相似文献