Previous studies have observed that electromagnetic induction can seriously affect the electrophysiological activity of the nervous system. Considering the role of astrocytes in regulating neural firing, we studied a ...Previous studies have observed that electromagnetic induction can seriously affect the electrophysiological activity of the nervous system. Considering the role of astrocytes in regulating neural firing, we studied a simple neuron–astrocyte coupled system under electromagnetic induction in response to different types of external stimulation. Both the duration and intensity of the external stimulus can induce different modes of electrical activity in this system, and thus the neuronal firing patterns can be subtly controlled. When the external stimulation ceases, the neuron will continue to fire for a long time and then reset to its resting state. In this study, "delay" is defined as the delayed time from the firing state to the resting state, and it is highly sensitive to changes in the duration or intensity of the external stimulus. Meanwhile, the self-similarity embodied in the aforementioned sensitivity can be quantified by fractal dimension. Moreover, a hysteresis loop of calcium activity in the astrocyte is observed in the specific interval of the external stimulus when the stimulus duration is extended to infinity, since astrocytic calcium or neuron electrical activity in the resting state or during periodic oscillation depends on the initial state. Finally, the regulating effect of electromagnetic induction in this system is considered. It is clarified that the occurrence of "delay" depends purely on the existence of electromagnetic induction. This model can reveal the dynamic characteristics of the neuron–astrocyte coupling system with magnetic induction under external stimulation. These results can provide some insights into the effects of electromagnetic induction and stimulation on neuronal activity.展开更多
A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-S...A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-Stokes equations is developed under the ALE framework,coupled with the theory of shallow arch,which is approximated by Galerkin method.Further,the interactions between the unsteady flow and the shallow arch are studied in detail.In particular,the effect of the selfexcited vibration of the structure on aerodynamic performance of the airfoil is investigated deeply at various angles of attack.The results show that the lift-to-drag ratio has been increased greatly compared with the rigid airfoil.Finally,the relationship between the self-excited vibration and the evolution of the flow is analyzed using FFT tools.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11772242)China Postdoctoral Science Foundation(Grant No.2018M631140)。
文摘Previous studies have observed that electromagnetic induction can seriously affect the electrophysiological activity of the nervous system. Considering the role of astrocytes in regulating neural firing, we studied a simple neuron–astrocyte coupled system under electromagnetic induction in response to different types of external stimulation. Both the duration and intensity of the external stimulus can induce different modes of electrical activity in this system, and thus the neuronal firing patterns can be subtly controlled. When the external stimulation ceases, the neuron will continue to fire for a long time and then reset to its resting state. In this study, "delay" is defined as the delayed time from the firing state to the resting state, and it is highly sensitive to changes in the duration or intensity of the external stimulus. Meanwhile, the self-similarity embodied in the aforementioned sensitivity can be quantified by fractal dimension. Moreover, a hysteresis loop of calcium activity in the astrocyte is observed in the specific interval of the external stimulus when the stimulus duration is extended to infinity, since astrocytic calcium or neuron electrical activity in the resting state or during periodic oscillation depends on the initial state. Finally, the regulating effect of electromagnetic induction in this system is considered. It is clarified that the occurrence of "delay" depends purely on the existence of electromagnetic induction. This model can reveal the dynamic characteristics of the neuron–astrocyte coupling system with magnetic induction under external stimulation. These results can provide some insights into the effects of electromagnetic induction and stimulation on neuronal activity.
基金This research is supported by Program for New Century Excellent Talents in University in China,No.NCET-07-0685.
文摘A localized flexible airfoil at low Reynolds numbers is modeled and the aerodynamic performance is analyzed numerically.With characteristic based split scheme,a fluid solver for two dimensional incompressible Navier-Stokes equations is developed under the ALE framework,coupled with the theory of shallow arch,which is approximated by Galerkin method.Further,the interactions between the unsteady flow and the shallow arch are studied in detail.In particular,the effect of the selfexcited vibration of the structure on aerodynamic performance of the airfoil is investigated deeply at various angles of attack.The results show that the lift-to-drag ratio has been increased greatly compared with the rigid airfoil.Finally,the relationship between the self-excited vibration and the evolution of the flow is analyzed using FFT tools.
