Energy estimation and coupling synchronization between biophysical neurons

Static charges can induce spatial electric field while moving charges can induce magnetic field. As a result, continuous pumping and exchange of intercellular and extracellular Calcium, potassium and sodium of cells will generate time-varying magnetic field in the media. Therefore, the physical effect of electromagnetic induction in neural activities should be included in building biological neurons. On the other hand, the occurrence of action potential and propagation of ions require energy consumption and supply, so the estimation of physical energy becomes important. Based on our memristive biophysical neuron model, the Hamilton energy function is obtained by using the Helmholtz’s theorem, and this energy is contributed by the electric field and magnetic field described by magnetic flux. It is found that this improved neuron model can present the main dynamical properties in neural activities, and it characterizes the lower threshold behavior and subthreshold oscillation during refractory period. The external forcing current on an isolate is adjusted to calculate the firing patterns, energy function and mode transition, which shows the dependence of energy on electrical activities. Finally, magnetic coupling is triggered to modulate the phase synchronization between two identical neurons connected by electric synapse, respectively.     

A review for dynamics of collective behaviors of network of neurons

The nervous system is composed of a large number of neurons, and the electrical activities of neurons can present multiple modes during the signal transmission between neurons by changing intrinsic bifurcation parameters or under appropriate external forcing. In this review, the dynamics for neuron, neuronal network is introduced, for example, the mode transition in electrical activity, functional role of autapse connection, bifurcation verification in biological experiments, interaction between neuron and astrocyte, noise effect, coherence resonance, pattern formation and selection in network of neurons. Finally, some open problems in this field such as electromagnetic radiation on electrical activities of neuron, energy consumption in neurons are presented.     

Energy dependence on modes of electric activities of neuron driven by different external mixed signals under electromagnetic induction

Energy supply and release play an important role in individual neuron and neural network. In this paper, the electrical activities and Hamilton energy of neuron are investigated when external mixed signals(i.e., the periodic stimulus current and the periodic electromagnetic field) are imposed on the neuron under the electromagnetic induction. As a result, the Hamilton energy is much dependent on the mode transition, the multiple electric activity modes and the numerical analysis of Hamilton energy are more complicated under various parameters. When the periodic high-low frequency electromagnetic radiation is imposed in neuron, it is found that the electrical activities are more complex, and the changing of energy is obvious. In addition, the response of electrical activity and Hamilton energy is much dependent on the changing of amplitude A, B when the external high-low frequency signal is imposed on the neuron, meanwhile, the energy of bursting state is lower than the one of spiking state. It can be used for investigation about the energy coding in the neuron even the neuron networks.     

Correlation of electromagnetic radiation emitted from coal or rock to supporting resistance

More accurate forecasting of rock burst might be possible from observations of electromagnetic radiation emitted in the mine. We analyzed experimental observations and field data from the Muchengjian coal mine to study the relationship between electromagnetic radiation signal intensity and stress during the fracturing of coal, or rock, and samples under load. The results show that the signal intensity is positively correlated with stress. In addition, we investigated the change in the electromagnetic radiation intensity, the supporting resistance in a real coal mine environment, and the coal or rock stress in the mining area. The data analysis indicates that: 1) electromagnetic radiation intensity can accurately reflect the distribution of stress in the mining area; and, 2) there is a correlation between electromagnetic radiation intensity and supporting resistance. The research has some practical guiding significance for rock burst forecasting and for the prevention of accidents in coal mines.     

Electrical activities of neural systems exposed to sinusoidal induced electric field with random phase

The brain neural system is often disturbed by electromagnetic and noise environments, and research on dynamic response of its interaction has received extensive attention. This paper investigates electrical activity of Morris-Lecar neural systems exposed to sinusoidal induced electric field(IEF) with random phase generated by electromagnetic effect. By introducing a membrane depolarization model under the effect of random IEF, transition state of firing patterns, including mixed-mode oscillations(MMOs) with layered inter-spike intervals(ISI) and intermittency with a power law distribution in probability density function of ISI, is obtained in a single neuron. Considering the synergistic effects of frequency and noise, coherence resonance is performed by phase noise of IEF under certain parameter conditions. For the neural network without any internal coupling, we demonstrate that synchronous oscillations can be induced by IEF coupling, and suppression of synchronous spiking is achieved effectively by phase noise of IEF. Results of the study enrich the dynamical response to electromagnetic induction and provide insights into mechanisms of noise affecting information coding and transmission in neural systems.     

Enhancement of pacemaker induced stochastic resonance by an autapse in a scale-free neuronal network

An autapse is an unusual synapse that occurs between the axon and the soma of the same neuron. Mathematically, it can be described as a self-delayed feedback loop that is defined by a specific time-delay and the so-called autaptic coupling strength. Recently, the role and function of autapses within the nervous system has been studied extensively. Here, we extend the scope of theoretical research by investigating the effects of an autapse on the transmission of a weak localized pacemaker activity in a scale-free neuronal network. Our results reveal that by mediating the spiking activity of the pacemaker neuron, an autapse increases the propagation of its rhythm across the whole network, if only the autaptic time delay and the autaptic coupling strength are properly adjusted. We show that the autapse-induced enhancement of the transmission of pacemaker activity occurs only when the autaptic time delay is close to an integer multiple of the intrinsic oscillation time of the neurons that form the network. In particular, we demonstrate the emergence of multiple resonances involving the weak signal, the intrinsic oscillations, and the time scale that is dictated by the autapse. Interestingly, we also show that the enhancement of the pacemaker rhythm across the network is the strongest if the degree of the pacemaker neuron is lowest. This is because the dissipation of the localized rhythm is contained to the few directly linked neurons, and only afterwards, through the secondary neurons, it propagates further. If the pacemaker neuron has a high degree, then its rhythm is simply too weak to excite all the neighboring neurons, and propagation therefore fails.     

Dynamics of electric activities in neuron and neurons of network induced by autapses

The effect of autapse on adjusting the membrane of potentials of neuron is described by imposing a time-delayed feedback on the membrane of neuron in a close loop type,and the Hindmarsh-Rose(HR)neuron under autapse is investigated.Firstly,the electric activity of single HR neuron under electric autapse and chemical autapse is investigated.It is found that quiescent neuron is activated due to appropriate time delay and feedback gain in the autapse,and the autapse plays an important role in waking up neuron.The parameter region for periodic,chaotic activity of neuron under autapse is calculated in a numerical way,and transition from spiking to bursting is observed by increasing the feedback gain and time delay carefully.Furthermore,the collective electric activities of neurons in a ring network is investigated and abundant electric activities are observed due to the competition between the autapse and the time-delayed coupling between adjacent neurons in the network,and time delay in coupling between neurons also plays an important role in enhancing synchronization in the network.     

圆柱形波导梳状线谐振器间电耦合特性分析

着重分析了加载U字型和一字型耦合杆的圆柱形波导梳妆线谐振器间电耦合特性。利用三维电磁场仿真软件HFSS计算得到了腔内电场和磁场分布,并给出了重要的实用耦合特性曲线。得到的部分实验结果与理论分析结果吻合的很好。最后,利用这样的电耦合以及磁耦合设计的九单元交叉耦合梳妆线滤波器进一步证实了理论分析的正确性。     

航天器屏蔽电缆电磁辐射的分析与测试

为了减小屏蔽电缆对航天器的影响,提出了基于传输阻抗和屏蔽层共模信号的电磁辐射分析方法.采用Kley模型分析内导体与屏蔽层之间的传输阻抗,将共模信号进行电流元分解;采用赫兹偶极子等效模型分析电缆的电场辐射.用辐射法测试屏蔽电缆的电磁辐射,以实现在常规电磁兼容性实验室开展测试的目标.仿真分析和实验结果证明,该方法可对屏蔽电缆的电磁辐射进行有效地分析和测试,可应用于航天器电缆的电磁兼容性分析和测试.     

Memristive neuron model with an adapting synapse and its hardware experiments

Electromagnetic induction effect caused by neuron potential can be mimicked using memristor. This paper considers a fluxcontrolled memristor to imitate the electromagnetic induction effect of adapting feedback synapse and presents a memristive neuron model with the adapting synapse. The memristive neuron model is three-dimensional and non-autonomous. It has the time-varying equilibria with multiple stabilities, which results in the global coexistence of multiple firing patterns. Multiple numerical plots are executed to uncover diverse coexisting firing patterns in the memristive neuron model. Particularly, a nonlinear fitting scheme is raised and a fitting activation function circuit is employed to implement the memristive mono-neuron model. Diverse coexisting firing patterns are observed from the hardware experiment circuit and the measured results verify the numerical simulations well.     

Synchronization of two electrically coupled inspiratory pacemaker neurons

Synchronization is considered to be a crucial mechanism that maintains respiratory rhythm.For understanding the effect of electrical coupling on the transition of the firing patterns and synchronization,we coupled two inspiratory pacemaker neurons together,and studied various synchronous behaviors between them.We firstly compared the bifurcation diagrams between the coupled neurons and single neuron,and found that the coupled neurons had a more complicated bifurcation mode.By increasing the coupling strength,the regular variation of phase differences was illustrated so that asynchronous and some synchronous states could be observed.These synchronous states were also shown in detail by phase portraits and firing series.In addition,we explored the ranges of different synchronous states,which attributed to different ranges of membrane capacitance and coupling strength.     

Spatiotemporal dynamics in a network composed of neurons with different excitabilities and excitatory coupling

Spiral waves have been observed in the biological experiments on rat cortex perfused with drugs which can block inhibitory synapse and switch neuron excitability from type II to type I. To simulate the spiral waves observed in the experiment, the spatiotemporal patterns are investigated in a network composed of neurons with type I and II excitabilities and excitatory coupling. Spiral waves emerge when the percentage (p) of neurons with type I excitability in the network is at middle levels, which is dependent on the coupling strength. Compared with other spatial patterns which appear at different p values, spiral waves exhibit optimal spatial correlation at a certain spatial frequency, implying the occurrence of spatial coherence resonance-like phenomenon. Some dynamical characteristics of the network such as mean firing frequency and synchronous degree can be well interpreted with distinct properties between type I excitability and type II excitability. The results not only identify dynamics of spiral waves in neuronal networks composed of neurons with different excitabilities, but also are helpful to understanding the emergence of spiral waves observed in the biological experiment.     

汽车电器电磁干扰及防护的探讨

随着计算机信息处理能力的提高,现代汽车装备有各式各样由电器或电子器件构成的系统,但是只要是带电的物体都会对周围产生辐射或受到其他磁场的辐射而受到影响.通过分析现代汽车电器电磁干扰现象及其产生机理,结合我国对现代汽车电磁兼容的标准,提出了5种抑制汽车电器电磁干扰的方法.防止和降低汽车电器的电磁干扰,对汽车行驶安全起着重要...     

电磁超声表面波辐射声场的三维有限元分析

为了得到电磁超声表面波换能器在被测试件表面和内部的辐射声场分布,采用ANSYS有限元仿真软件对电磁超声换能器辐射声场进行仿真.建立了电磁超声换能器三维有限元模型并进行了优化,给出了被测试件中感生涡流与换能器激励线圈参数的量化关系.通过电磁结构耦合的方法得到被测试件内部及表面不同方向质点的位移变化,分析了在被测试件内部的辐射声场分布,并给出了被测试件表面辐射声场的指向性规律.根据仿真模型搭建了电磁超声探伤平台,实验结果与指向角仿真结果基本吻合.实验结果表明：对电磁超声表面波辐射声场的有限元仿真,为其设计优化、实际探伤范围的确定、接收线圈放置位置,以及收发装置的安装角度提供了依据.     

屏蔽系统HPM效应的拓扑图分析与防护加固

提出了一种屏蔽计算机系统的高功率微波效应拓扑图分析方法。实现了屏蔽系统的电磁拓扑图,分析了HPM的孔缝耦合进入腔体的极化规律,用扩展BLT方程分析了线缆在HPM辐照下能量进入屏蔽系统的规律;强调了在屏蔽电子系统HPM效应拓扑图的研究中,HPM的频率和极化是表示屏蔽系数的两个重要的效应参数,最终用以这两个参数为变量的矩阵表示了系统HPM效应拓扑图,用最短路径算法求解该矩阵,可求得从源点到终点总屏蔽系数小于一定值,需要加固的电磁耦合路径。     

单轴压缩下不同含水状态砂岩损伤演化试验

为了研究不同含水状态岩石损伤演化特性,利用RMT-150C岩石力学试验机、AEwin-USB型声发射信号采集系统和KBD5电磁辐射采集系统,对干燥、自然和饱水状态下的红砂岩进行单轴压缩声电信号监测试验.基于岩石破坏过程中声发射振铃计数、电磁辐射脉冲数和应力变化,建立了砂岩损伤演化模型.结果表明:声发射、电磁辐射信号和损...     

Effects of electromagnetic induction and noise on the regulation of sleep wake cycle

As an exploration of electromagnetic induction effects on homeostatic regulation of sleep wake cycle, a magnetic flux term coupled with membrane current is proposed as an equivalent induction current act on a physiologically-motivated mathematical model, to study the effects of electromagnetic induction and its noise on the sleep wake cycle. The basic model includes 2 simplified Hodgkin-Huxley type neurons connected via glutamate(Glu) synapses, one of which additionally contains hypocretin/orexin(Hcrt/ox) as the functionally relevant co-transmitter. The numerical results suggest that when a constant current(DC) stimulus is applied to the model, the average fire frequency of the Hcrt/ox neuron could be modified from gamma to delta frequency with increased the intensity of electromagnetic induction, but the local Glu neuron transforms active into sleep state.Additionally, the homeostatic regulation function has better robustness to electromagnetic induction and its noise than the current or conductance noise, even there is a similar stochastic resonance phenomenon. For the circadian current input case, the time of wake up is delayed and fall asleep is advanced when the electromagnetic induction and its noise is considered. Furthermore, the effects of electromagnetic noise on the regulation is not significant, but only to inhibit the neuronal discharge activities and change the time of wake up and fall asleep of the Glu neuron, characterized by the sleep duration is slightly prolonged with increasing the strength of noise intensity.     

高空高能带电粒子流

本文介绍高空高能电子研究进展,揭示接近宇宙空间的高能电子形成机制,高空高能带电粒子流和地震活动性之间的关系。指出在震中地区,地震形成过程中发射电磁辐射是高能带电粒子流和地震活动性之间存在关系的重要原因。     

ESD脉冲辐射电磁场瞬态仿真与分析

现今电子电路的结构越来越复杂,大量的无源器件集成在PCB各个模块上,这些元器件极易收到来自外界的EMS干扰信号的干扰,通常情况人们将目光集中于中低频段信号通过传导耦合串扰直接进入设备,而忽略了EMS干扰的高频特性会在近场范围内通过空间磁场施加在模块上. 本文通过模拟静电放电(ESD)脉冲电磁辐射场,分析其在近场对PCB板级电路上的复杂无源模块产生的辐射干扰,并且对无源模块周围受到影响产生的场进行仿真并且得出时域上的信号强度分布.     

基于无线供电太阳能加热器的设计

无线输电技术具有广泛的应用前景,其传送原理可分为三种：电磁感应原理、电磁辐射原理和电磁谐振原理.白天,将太阳能转换为电能储存在蓄电池中;黑天时,自动控制无线发射线圈产生电磁波辐射,利用电磁辐射原理接收线圈耦合得到电能并提供给负载,供特殊环境下的人们保暖使用.