搜索结果: 136-150 共查到“知识库 常微分方程”相关记录552条 . 查询时间(5.147 秒)
Uniform convergence analysis of an upwind finite difference approximations of an homogenous singularly perturbed boundary value problem using grid equidistribution
singular perturbation adaptive grid rate of convergence error estimate
2011/10/13
We derive varepsilon-uniform error estimates for two first-order upwind discretizations of a model inhomogeneous, second-order, singularly perturbed boundary value problem on a non-uniform grid. Here,...
本文研究了一类四阶时滞微分方程的分支。首先,通过分析特征方程根的分布研究了方程的线性稳定性。我们发现随着时滞的变化,系统有稳定性开关,且在一些临界值处处系统经历了Hopf分支。进而,应用中心流形理论和规范型方法给出了关于确定分支方向和分支周期解的稳定性的计算公式。最后给出了几组数值模拟说明理论分析结果。
常系数线性非齐次方程组特解的求法—待定系数法
常系数线性非齐次方程组 秩 特解 解的叠加 特征根 待定系数法
2011/10/13
本文研究了求常系数线性非齐次方程组特解的方法—待定系数法。文章从研究非齐次项为常数向量与 相乘的常系数线性非齐次方程组的特解入手,依次给出了特征值是方程组系数矩阵的k重特征根时的特解解型;进而推广到非齐次项为多项式的常系数线性非齐次方程组的特解解型;又利用已推出的结论和解的叠加原理,导出了非齐次项为其分量是多项式的常系数线性非齐次方程组的特解解型。本文结合实例说明了用待定系数法求常系数线性非齐次方...
Partial Answers on Saari’s Conjecture of N-body problems
N-body problems Relative equilibria Central configurations Variational methods
2011/10/13
One special periodic solution of the Newtonian N-body problems is relative equilibria,which rotates rigidly about their center of mass.In 1970,Donald G.Saari conjectured:if the moment of inertia of N-...
半直线上一类一维问题唯一解在零点附近的渐近行为
一维问题 唯一解 渐近行为
2011/10/13
应用摄动方法,非线性变换和Karamata 正规变化理论,构造上下解,在b 和g 满足适当的结构条件下, 得到了半直线上一维奇异边值问题唯一解在零点附近的渐近行为.这里, g,b∈C^1(0,∞),且在(0,∞)上为正的单调递增函数. 所给的两个结构条件隐含了g 在无穷远处以指数q(q>1) 正规变化或快速变化(快速趋于∞).
一类半正奇异非线性三点边值问题的正解
正解 三点边值问题 半正 锥
2011/10/12
应用锥拉伸与压缩不动点定理研究一类半正奇异非线性三点边值问题的正解的存在性,采用一种利用辅助函数的方法讨论更一般的奇异二阶三点边值问题,得到了一个正解的存在性定理。其中允许非线性项有一个负的下界,推广和改进了一些已知的结果。
一类SEIS传染病模型在均匀网络上的研究
SEIS模型 均匀网络 临界阈值 仿真
2011/10/12
研究均匀网络上一类具有潜伏期的SEIS传染病模型. 首先利用平均场理论得到了疾病传播的临界阈值,分析得到该临界阈值不仅受网络中节点治愈率的影响,另外潜伏期个体的存在也会对其产生影响.证明了无病平衡点和地方病平衡点的全局性态完全由此临界阈值确定。最后通过数值仿真验证了理论结果的正确性。
Positive Solutions of Semipositone BVPs for Differential Systems on Time Scales
Positive solution Semipositone boundary value problem Differential systems Time scales
2011/10/12
The paper is concerned with the semipositone Sturm-Liouville-like boundary value problems of second-order differential systems on time scales with two parameters. Applying a fixed point theorem in con...
Semipositone Problems of Second Order Ordinary Differential Equations
Positive solution Semipositone boundary value problem Ordinary differential equation
2011/10/12
The paper is concerned with the semipositone boundary value problems of second-order ordinary differential equations. Applying a fixed point theorem in cones, an existence result of at least one posit...
Banach空间中Duffing方程的周期边值问题
反向上下解 Banach空间 周期边值问题
2011/10/12
本文在上下解反向给定时,通过利用华罗庚不等式等重要不等式证明了新的比较定理,并在Banach空间中利用半序理论和新的比较定理,研究了Duffing方程周期边值问题最小解和最大解的存在性、唯一性,得到了更为一般的结果,推广了一些前人的结论。
Existence of n Positive Solutions for Some Fourth-order Boundary Value Problems
nonlinear fourth-order boundary value problems positive solution existence multiplicity fixed point theorem on cone Leray-Schauder continuous principle
2011/10/12
The authors apply Leray-Schauder continuous principle theorem and Krasnosel’skii fixed point theorem of cone expansion-compression type to a class of nonlinear fourth-order two-point boundary value pr...
Existence of n Positive Solutions for Some Fourth-order Boundary Value Problems
nonlinear fourth-order boundary value problems positive solution existence multiplicity fixed point theorem on cone Leray-Schauder continuous principle
2011/10/12
The authors apply Leray-Schauder continuous principle theorem and Krasnosel’skii fixed point theorem of cone expansion-compression type to a class of nonlinear fourth-order two-point boundary value pr...
一些学者通过常微分方程的研究方法和技巧研究了分数阶微分方程并且获得了相当不错的结果。本文将常微分方程解的单调迭代法和Nagumo型条件引入到分数微分方程中来,证明了一类分数微分系统解的存在唯一性。另外,通过分数阶微分不等式等手段推广了V.Lakshmikantham等人的结果。
一类具功能性反应的食饵—捕食者两种群模型的定性分析
平衡点 极限环 存在惟一性
2011/10/12
本文研究了一类具功能性反应的食饵——捕食者两种群模型。利用微分方程定性理论,当给定参数满足一定条件下,讨论了该系统平衡点的稳定性态。运用Dulac函数法,得到了系统不存在闭轨的充分条件。运用Poincare-Bendixson环域定理,证明了极限环的存在性。运用张芷芬惟一性定理,证明了极限环的惟一性。
Nonexistence of formal first integrals for nonlinear systems under resonance
Non-integrability Resonance First integral Normal form
2011/10/12
In this paper, by using normal form theory we give some criteria of nonexistence of formal first integrals for general nonlinear systems under resonance. As application, we also give a criterion for n...