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1.
The influence of long-range links on spiral waves in an excitable medium has been investigated.Spatiotemporal dynamics in an excitable small-world network transform remarkably when we increase the long-range connection probability P.Spiral waves with few perturbations,broken spiral waves,pseudo spiral turbulence,synchronous oscillations,and homogeneous rest state are discovered under different network structures.Tip number is selected to detect non-equilibrium phase transition between different spatiotemporal patterns.The Kuramoto order parameter is used to identify these patterns and explain the emergence of the rest state.Finally,we use long-range links to successfully control spiral waves and spiral turbulence. 相似文献
2.
In this paper we investigate spatiotemporal pattern formation in excitable media with only a long-range link. Besides the trivial solutions of spiral patterns, we find the asymptotic self-sustained target waves in the autonomous tissues. The wave source supporting this kind of new pattern is the oscillatory one-dimensional Winfree-loop self-organized under the presence of a long-range link, which is explored by the dominant phase-advanced driving method. Based on this understanding we can effectively regulate the oscillations of excitable media by suitably arranging the long-range link, including construction of self-sustained target waves with controllable period and wave length, or manipulation of system states between different patterns. 相似文献
3.
YUAN Guo-Yong WANG Guang-Rui CHEN Shi-Gang 《理论物理通讯》2005,44(5):858-862
Spiral waves and spatiotemporal chaos usually are harmful and need to be suppressed. In this paper, a method is proposed to control them. Travel wave trains can be generated by periodic excitations near left boundary, spiral waves and spatiotemporal chaos can be eliminated by the trains for some certain excitation periods. Obvious resonant behavior can be observed from the relation between the periods of the trains and excitation ones. The method is against noise. 相似文献
4.
Spiral waves and spatiotemporal chaos usually are harmful and need to be suppressed. In this paper, a method is proposed to control them. Travel wave trains can be generated by periodic excitations near left boundary,spiral waves and spatiotemporal chaos can be eliminated by the trains for some certain excitation periods. Obvious resonant behavior can be observed from the relation between the periods of the trains and excitation ones. The method is against noise. 相似文献
5.
In this paper, an intermittent local electric shock scheme is proposed tosuppress stable spiral waves in the Barkley model by a weak electric shock(about 0.4 to 0.7) imposed on a random selected n×n grids (n=1-5,compared with the original 256×256 lattice) and monitoredsynchronically the evolutions of the activator on the grids as the sampledsignal of the activator steps out a given threshold (i.e., the electricshock works on the n×n grids if the activatoruleq0.4 or u geq 0.8). The numericalsimulations show that a breakup of spiral is observed in the mediastate evolution to finally obtain homogeneous states if the electricshock with appropriate intensity is imposed. 相似文献
6.
This paper proposes a scheme of parameter perturbation to suppress the stable rotating spiral wave, meandering spiral wave and turbulence in the excitable media, which is described by the modified Fitzhug-Nagumo （MFHN） model. The controllable parameter in the MFHN model is perturbed with a weak pulse and the pulse period is decided by the rotating period of the spiral wave approximatively. It is confirmed that the spiral wave and spiral turbulence can be suppressed greatly. Drift and instability of spiral wave can be observed in the numerical simulation tests before the whole media become homogeneous finally. 相似文献
7.
为了模拟电击除颤导致动作电位持续时间缩短, 在Luo-Rudy相I心脏模型中引入了同步复极化. 研究了同步复极化对螺旋波和时空混沌动力学的影响. 数值结果表明: 在控制周期比较小的情况下, 同步复极化可以有效消除螺旋波和时空混沌, 在有一些控制参数下, 同步复极化只能消除螺旋波, 或者只能消除时空混沌. 当螺旋波不被控制时, 观察到螺旋波转变为长周期和长波长的螺旋波或破碎成时空混沌的现象. 并对控制机制进行了分析.关键词：螺旋波时空混沌同步复极化控制 相似文献
8.
C. Gay;P.-G. De Gennes;R. Kant 《Europhysics letters》1996,34(8):581-586
On a solid substrate, superfluid may show stratified liquid films (above a solid layer). Assuming the existence of these films, weanalyse the dynamics of wetting for a two-layer droplet which tends to spread and transform into a one-layer droplet (at low temperature: no vapour phase is present). The permeation process between layers, which exists in classical liquids, isreplaced here by a Josephson coupling. Spreading should occur via Josephson vorticesthat drift towards the centre of the droplet.https://doi.org/10.1209/epl/i1996-00498-4 相似文献
9.
10.
MA Jun YI Ming ZHANG Li-Ping JIN Wu-Yin LI Yan-Long 《理论物理通讯》2008,49(6):1541-1546
In this paper, a new scheme of spatial perturbation is proposed to stabilize the pattern in the oscillatory media, which could be described with the complex Ginzburg-Landau equation. The numerical simulation results confirm that the spiral wave, antispiral wave and spatiotemporal chaos in the complex Ginzburg-Landau equation could be suppressed, and the scheme is also discussed with the conservative field theory. Furthermore, the spatiotemporal noise is also introduced into the whole media, it just confirms that it is robust to the spatiotemporal noise. 相似文献
11.
The electromagnetically driven liquid metal flow in a toroidal duct of a square cross-section is studied numerically searching for the critical Reynolds (Re) and Hartmann (Ha) numbers where transition occurs. Results are reported for Ha up to 500, building a transition map of critical Reynolds and Hartmann numbers and showing two distinct regimes of transition signified by the destabilization of the secondary flow: The first, for Ha<18, where the Lorentz force is balanced by fluid momentum diffusion and the second, for Ha⩾18, where it is balanced by fluid inertia. In both cases, the destabilization of the secondary flow occurs primarily near the concave sidewall. For Ha⩾18 the transition follows approximately the relationship Re=16.803Ha1.43 for values of Re and Ha in the range 80<Re/Ha<224.https://doi.org/10.1209/0295-5075/101/44005 相似文献
12.
采用Greenberg-Hastings元胞自动机模型研究机械形变对心肌组织中螺旋波动力学行为的影响.数值模拟表明：对于规则网格下的稳定螺旋波,在生理性机械形变作用下,螺旋波发生漫游但不破碎;在病理性机械形变作用下,螺旋波会发生持续漫游、漫游后消失和破碎进入螺旋波湍流态三种变化.通过对比发现机械形变的振幅变化率对螺旋波的影响较大,而机械形变的角频率对螺旋波的影响较小.结合数值模拟,对心前区受到猛烈撞击会出现心颤致死及耐力运动员在发生心动过速后比一般人员更容易恢复正常进行解释. 相似文献
13.
Langmuir turbulence is an archetype of wave turbulence in plasma physics. By means of 1D-1V Vlasov-Poisson simulations, we show that coherent structures, called Langmuir cavitons, are generated by the long-time evolution of Langmuir weak-turbulence, thus illustrating the breakdown of a weak-turbulence regime. These structures correspond to an equilibrium between the pressure forces and the ponderomotive force resulting from high-frequency Langmuir oscillations. Langmuir cavitons are typical features of strong Langmuir turbulence expected to be generated at high energy and to saturate when Langmuir energy is of the order of the plasma thermal energy. Despite this wide-spread belief, here we observe that cavitons, emerging from weak Langmuir turbulence evolution, saturate at much lower energies. We show that these Langmuir coherent structures are characterized by a much larger length scale with respect to the Debye length. This gives evidence that “large” and “shallow” stable cavitons should be seen in space plasma observations. The transition toward strong turbulence is shown to be a consequence of an initial weak turbulent inverse cascade. Finally, the effective equation of state for ion acoustic oscillations is tested numerically from the kinetic model.https://doi.org/10.1209/0295-5075/96/55004 相似文献
14.
Yingle Li Jiying Huang Ruike Yang 《International Journal of Infrared and Millimeter Waves》2002,23(3):435-443
Dust storms and turbulence consist of a random medium system, its effects on milimeter waves propagation are studied. Attenuation of millimeter waves, its phase shift and cross- polar discrimination are presented. Results show that dust storms mainly effects XPD and phase shift of millimeter waves, turbulence chiefly produces attenuation, in mediocre fluctuation. 相似文献
15.
Starting with the very definition of chaos, we demonstrate that the study of chaos is not an abstract one but can lead to
some useful practical applications. With the advent of some powerful mathematical techniques and with the availability of
fast computers, it is now possible to study the fascinating phenomena of chaos — the subject which is truly interdisciplinary.
The essential role played by fractals, strange attractors, Poincare maps, etc., in the study of chaotic dynamics, is briefly
discussed. Phenomena of self-organization, coherence in chaos and control of chaos in plasmas is highlighted. 相似文献
16.
We demonstrate theoretically and numerically the zonal-flow/drift-wave feedback mechanism in an idealised 2-dimensional model of plasma turbulence driven by a small-scale instability. Zonal flows are generated by a secondary modulational instability of the modes which are directly driven by the primary instability. The zonal flows then suppress the small scales thereby arresting the energy injection into the system, a process which can be described using nonlocal (in scale) wave turbulence theory. Finally, the arrest of the energy input results in saturation of the zonal flows at a level which can be estimated from the theory and the system reaches stationarity without large-scale dissipation.https://doi.org/10.1209/0295-5075/96/25001 相似文献
17.
采用LuoRud91模型研究了螺旋波和时空混沌的抑制,提出用局域反馈控制方法抑制螺旋波和时空混沌,采用静止和运动控制器两种控制策略.结果表明:适当选择控制参数,静止控制器的局域反馈方法能很好抑制螺旋波,但不能有效抑制时空混沌;采用运动控制器的局域反馈方法能有效抑制螺旋波和时空混沌,抑制速度与控制器移动的速度有关,在选择适当的控制参数下,螺旋波和时空混沌能在很短的时间内被抑制. 相似文献
18.
用钙离子通道激动剂抑制心脏组织中的螺旋波和时空混沌 总被引：2，自引：0，他引：2
本文以LuoRudy91模型为基础,研究心脏组织中的螺旋波和时空混沌的抑制.提出应用钙离子通道激动剂来提高慢速内行钙离子流的最大电导率—Gsi,达到抑制螺旋波和时空混沌的目的.研究结果表明:该方法可以有效抑制心脏组织中的螺旋波和时空混沌,即使系统出现含时外行钾离子流的最大电导率—GK分布不均匀,该控制方法仍然有效.对控制机理进行了分析. 相似文献
19.
We studied synchronization behaviours of spiral waves in a two-layercoupled inhomogeneous excitable system. It was found that phasesynchronization can be observed under weak coupling strength. Byincreasing the coupling strength, the synchronization is brokendown. With the further increase of the coupling strength, completesynchronization and phase synchronization occur again. We also foundthat the inhomogeneity in excitable systems is helpful to thesynchronization. 相似文献
20.
Spiral waves are ubiquitous phenomena in nonlinear chemical, physical, and biological systems. But antispiral waves are infrequent to date. The transition between spiral and antispiral waves has been rarely explored. We have analyzed the extended Brusselator model and the extended Oregonator model by linear stability analysis. We have demonstrated that it is possible and plausible to realize the transition between them by control of diffusion coefficient of inactivator from theoretical analysis and numerical simulations. 相似文献