In this paper, an intermittent local electric shock scheme is proposed to suppress 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 ...In this paper, an intermittent local electric shock scheme is proposed to suppress 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 monitored synchronically the evolutions of the activator on the grids as the sampled signal of the activator steps out a given threshold （i.e., the electric shock works on the n ~ n grids if the activator u ≤ 0.4 or u ≥ 0.8）. The numerical simulations show that a breakup of spiral is observed in the media state evolution to finally obtain homogeneous states if the electric shock with appropriate intensity is imposed.展开更多
Spirals generated from the excitable media within the Barkley model is investigated under the gradient electric fields by a numerical simulation. The spiral drift and spiral break up are observed when the amplitude of...Spirals generated from the excitable media within the Barkley model is investigated under the gradient electric fields by a numerical simulation. The spiral drift and spiral break up are observed when the amplitude of the electric fields is modulated by a constant signal or a chaotic signal. It is also verified that, even in the presence of the white noise, the whole system can reach homogeneous states after the spiral breakup, by using an adaptive strategy.展开更多
The transition from stationary to oscillatory states in dynamical systems under phase space compression is investigated. By considering the model for the spatially one-dimensional complex Ginzburg-Landau equation, we ...The transition from stationary to oscillatory states in dynamical systems under phase space compression is investigated. By considering the model for the spatially one-dimensional complex Ginzburg-Landau equation, we find that defect turbulence can be substituted with stationary and oscillatory signals by applying system perturbation and confining variable into various ranges. The transition procedure described by the oscillatory frequency is studied via numerical simulations in detail.展开更多
In isolated chick retina, the visualization of electrochemical self-organized patterns is possible due to the presence of macroscopic intrinsic optical signals (IOSs). Isolated circular waves, standing patterns, and s...In isolated chick retina, the visualization of electrochemical self-organized patterns is possible due to the presence of macroscopic intrinsic optical signals (IOSs). Isolated circular waves, standing patterns, and self-sustained sequences of spirals are all easily obtained using an IOS approach. In this paper we present the tight coupling and non-linear relationship between optical and electrical wave concomitants, and potassium-induced whole tissue excitability changes. Elementary statistical methods and time series analyses were applied to two sets of data: 1) solitary circular retinal spreading depression waves, and 2) tissue response to exogenous potassium fast pulses. The results were interpreted from the point of view of non-linear thermodynamical concepts and volume phase transitions in polyanionic gels according to the Tasaki action potential model. From these and previous results, it is clear that the glial network and extracellular matrix contribute to the propagation and emergence of these patterns.展开更多
The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear...The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear law are derived for untwisted organization center. These results have explicit physical meaning and are in good agreement with experiments.展开更多
文摘In this paper, an intermittent local electric shock scheme is proposed to suppress 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 monitored synchronically the evolutions of the activator on the grids as the sampled signal of the activator steps out a given threshold （i.e., the electric shock works on the n ~ n grids if the activator u ≤ 0.4 or u ≥ 0.8）. The numerical simulations show that a breakup of spiral is observed in the media state evolution to finally obtain homogeneous states if the electric shock with appropriate intensity is imposed.
基金Supported partially by the National Natural Science Foundation of China under Grant No 90303010.
文摘Spirals generated from the excitable media within the Barkley model is investigated under the gradient electric fields by a numerical simulation. The spiral drift and spiral break up are observed when the amplitude of the electric fields is modulated by a constant signal or a chaotic signal. It is also verified that, even in the presence of the white noise, the whole system can reach homogeneous states after the spiral breakup, by using an adaptive strategy.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos 10405018 and 70571053.
文摘The transition from stationary to oscillatory states in dynamical systems under phase space compression is investigated. By considering the model for the spatially one-dimensional complex Ginzburg-Landau equation, we find that defect turbulence can be substituted with stationary and oscillatory signals by applying system perturbation and confining variable into various ranges. The transition procedure described by the oscillatory frequency is studied via numerical simulations in detail.
文摘In isolated chick retina, the visualization of electrochemical self-organized patterns is possible due to the presence of macroscopic intrinsic optical signals (IOSs). Isolated circular waves, standing patterns, and self-sustained sequences of spirals are all easily obtained using an IOS approach. In this paper we present the tight coupling and non-linear relationship between optical and electrical wave concomitants, and potassium-induced whole tissue excitability changes. Elementary statistical methods and time series analyses were applied to two sets of data: 1) solitary circular retinal spreading depression waves, and 2) tissue response to exogenous potassium fast pulses. The results were interpreted from the point of view of non-linear thermodynamical concepts and volume phase transitions in polyanionic gels according to the Tasaki action potential model. From these and previous results, it is clear that the glial network and extracellular matrix contribute to the propagation and emergence of these patterns.
文摘The motion of organization center of three_dimensional untwisted scroll waves in excitable media with single diffusion is studied by singular perturbation method in this paper. The relation of curvature and the linear law are derived for untwisted organization center. These results have explicit physical meaning and are in good agreement with experiments.
