共查询到18条相似文献，搜索用时 78 毫秒
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本文研究了一类具有时滞的厄尔尼诺一南方波涛动模型．得到了该模型在平衡点稳定的充分条件．通过选择时滞η为分岔参数,得到了当时滞η通过一系列的临界值时,Hopf分岔产生,然后,应用中心流形和规范型理论,得到了确定Hopf分岔特性（例如Hopf分岔方向和分岔周期解的稳定性以及Hopf分岔周期解的周期等）的计算公式．最后进行数值模拟验证了所得结果的正确性． 相似文献
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研究了一类随机van der Pol 系统的Hopf分岔行为.首先根据Hilbert空间的正交展开理论,含有随机参数的van der Pol系统被约化为等价确定性系统,然后利用确定性分岔理论分析了等价系统的Hopf分岔,得出了随机van der Pol 系统的Hopf 分岔临界点,探究了随机参数对系统Hopf分岔的影响.最后利用数值模拟验证了理论分析结果.关键词：随机van der Pol系统Hopf分岔正交多项式逼近 相似文献
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A class of recharge–discharge oscillator model for the El Ni？o/Southern Oscillation （ENSO） is considered. A stable limit cycle is obtained by transforming the ENSO model into the van der Pol-Duffing equation. We proved that there exists periodic oscillations in the ENSO recharge–discharge oscillator model. 相似文献
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Motivated by an important practical significance, we analyze the noise-induced El Niño evolutionary equations. Our analysis based on the evaluation of largest Lyapunov exponents demonstrates the new effects of deterministic and stochastic dynamics of the El Niño–Southern Oscillation Events. We show that the non-linear deterministic model possesses either a multiturn limit cycle with regular self-oscillations or chaotic oscillations depending on slight variations of one of the main system parameters – the mean tropical easterlies. It is revealed that in the presence of noise, transformations of regular oscillations into chaotic ones are observed. 相似文献
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This paper applies washout filter technology to amplitude
control of limit cycles emerging from Hopf bifurcation of the van der
Pol--Duffing system. The controlling parameters for the appearance
of Hopf bifurcation are given by the Routh--Hurwitz criteria.
Noticeably, numerical simulation indicates that the controllers
control the amplitude of limit cycles not only of the weakly nonlinear van
der Pol--Duffing system but also of the strongly nonlinear van der
Pol--Duffing system. In particular, the emergence of Hopf bifurcation
can be controlled by a suitable choice of controlling parameters.
Gain-amplitude curves of controlled systems are also drawn. 相似文献
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Tamás Tél 《Journal of statistical physics》1988,50(5-6):897-912
A double expansion in powers of the damping coefficient and noise intensity is shown to be a powerful method for obtaining the stationary distribution of systems that after rescaling become weakly damped conservative ones. Systems undergoing Hopf bifurcations belong to this class. As an illustrative example, the generalized van der Pol oscillator is considered around its bifurcation point. A calculation is carried out up to third order in both the noise intensity and the bifurcation parameter (damping coefficient). 相似文献
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建立了一种可积的无穷维系统——时延范德波尔电磁系统,采用Poincaré映射分析了系统随参数E和λ变化发生的分岔与混沌现象,发现这种时延系统具有复杂的非线性动力学特性,例如吸引子共存、间歇性混沌、类似边界碰撞分岔通向混沌以及周期增加的现象.在研究系统时间混沌行为的同时,还对空间混沌行为进行了初步分析,通过描绘空间分布图发现时延范德波尔电磁系统随参数E和λ变化时,在空间中会呈现出周期和混沌等不同的图案.关键词：分岔混沌无穷维系统时延范德波尔电磁系统 相似文献
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Around 100 years after Carnegie expeditions discovered the Global Electric Circuit, a measuring campaign started at ARM, Eastern North Atlantic facility (Graciosa Island, Azores), meant for the first time to resemble the conditions in which those took place. Here, the first year of measurements (starting April 2015) are analysed and initial results are discussed. The Potential Gradient findings show a deviation from the Carnegie Curves towards inland measurements as a consequence of local aerosol and ion load. The Potential Gradient maxima evolves from 18 UTC (spring/autumn) to 20 UTC (summer), being consistent with the strong 2015 El Niño. 相似文献
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