Electrical coupling regulates layer 1 interneuron microcircuit formation in the neocortex

With the support by the National Natural Science Foundation of China,the research team led by Prof.Yu Yongchun(禹永春)at the Institutes of Brain Science,Fudan University,revealed the vital roles of electrical coupling in chemical synapse formation between interneurons,which was published in Nature Communications(2016,7:12229,DOI:10.1038).Although the excitatory neurons in the neocortex are electrically coupled only during early development,

Mixed Electric and Magnetic Coupling Design Based on Coupling Matrix Extraction

This paper proposes a design and fine-tuning method for mixed electric and magnetic coupling filters.It derives the quantitative relationship between the coupling coefficients(electric and magnetic coupling,i.e.,EC and MC)and the linear coefficients of frequencydependent coupling for the first time.Different from the parameter extraction technique using the bandpass circuit model,the proposed approach explicitly relatesEC and MC to the coupling matrix model.This paper provides a general theoretic framework for computer-aided design and tuning of a mixed electric and magnetic coupling filter based on coupling matrices.An example of a 7th-order coaxial combline filter design is given in the paper,verifying the practical value of the approach.

Effect of alternating ultrasonic frequency electric signal on the distribution of pore in aluminum alloy weld

The application of ultrasonic vibration in the welding process can effectively suppress the pore defects of the weld.The different ultrasonic application methods own different effects on the weld pore.In this paper,the ultrasonic frequency vibration in the weld pool is excited by the coupling of the ultrasonic frequency electrical signal and the welding electrical signal.The influence of ultrasonic excitation voltage and excitation frequency on porosity,number,location,and size of pore in weld was investigated.The results show that the variation of ultrasonic excitation voltage and frequency has a direct influence on the pore distribution.The pore defects can be decreased by the coupling of ultrasonic frequency electrical signal with reasonable parameters or increased by the coupling of ultrasonic frequency electrical signal with unreasonable parameters.The ultrasonic excitation frequency is fixed at 30 kHz and the ultrasonic excitation voltage is changed.The porosity of the weld is close to that of the weld without ultrasonic action when the ultrasonic excitation voltage is 25 V and 75 V.The porosity of the weld is significantly lower than that of the weld without ultrasonic action when the ultrasonic excitation voltage is 50 V and 100 V.The ultrasonic excitation voltage is fixed at 100 V and the ultrasonic excitation frequency is changed.The porosity of the weld is the largest and exceeds that of the weld without ultrasonic action when the ultrasonic excitation frequency is 20 kHz.The porosity of the weld is lower than that of the weld without ultrasonic action when the ultrasonic excitation frequency is 25,30,35,and 40 kHz.The pores were mainly concentrated on the upper part of the weld and the number of pores of small size increased significantly after the coupling of an ultrasonic frequency electrical signal,indicating that ultrasonic promoted the rise and escape of bubbles in the weld pool.

Coexisting fast–slow dendritic traveling waves in a 3D-array electric field coupled neuronal network

Coexistence of fast and slow traveling waves without synaptic transmission has been found in hhhippocampal tissues,which is closely related to both normal brain activity and abnormal neural activity such as epileptic discharge. However, the propagation mechanism behind this coexistence phenomenon remains unclear. In this paper, a three-dimensional electric field coupled hippocampal neural network is established to investigate generation of coexisting spontaneous fast and slow traveling waves. This model captures two types of dendritic traveling waves propagating in both transverse and longitude directions: the N-methyl-D-aspartate(NMDA)-dependent wave with a speed of about 0.1 m/s and the Ca-dependent wave with a speed of about 0.009 m/s. These traveling waves are synaptic-independent and could be conducted only by the electric fields generated by neighboring neurons, which are basically consistent with the in vitro data measured experiments. It is also found that the slow Ca wave could trigger generation of fast NMDA waves in the propagation path of slow waves whereas fast NMDA waves cannot affect the propagation of slow Ca waves. These results suggest that dendritic Ca waves could acted as the source of the coexistence fast and slow waves. Furthermore, we also confirm the impact of cellular spacing heterogeneity on the onset of coexisting fast and slow waves. The local region with decreasing distances among neighbor neurons is more liable to promote the onset of spontaneous slow waves which, as sources, excite propagation of fast waves. These modeling studies provide possible biophysical mechanisms underlying the neural dynamics of spontaneous traveling waves in brain tissues.

Unified probabilistic gas and power flow

The natural gas system and electricity system are coupled tightly by gas turbines in an integrated energy system. The uncertainties of one system will not only threaten its own safe operation but also be likely to have a significant impact on the other. Therefore, it is necessary to study the variation of state variables when random fluctuations emerge in the coupled system. In this paper, a multislack-bus model is proposed to calculate the power and gas flow in the coupled system. A unified probabilistic power and gas flow calculation, in which the cumulant method and Gram–Charlier expansion are applied, is first presented to obtain the distribution of state variables after considering the effects of uncertain factors. When the variation range of random factors is too large, a new method of piecewise linearization is put forward to achieve a better fitting precision of probability distribution. Compared to the Monte Carlo method, the proposed method can reduce computation time greatly while reaching a satisfactory accuracy.The validity of the proposed methods is verified in a coupled system that consists of a 15-node natural gas system and the IEEE case24 power system.

Optimal Operation of Integrated Energy Systems Subject to Coupled Demand Constraints of Electricity and Natural Gas

This paper proposes a hybrid multi-objective optimization and game-theoretic approach(HMOGTA)to achieve the optimal operation of integrated energy systems(IESs)consisting of electricity and natural gas(E&G)utility networks,multiple distributed energy stations(DESs),and multiple energy users(EUs).The HMOGTA aims to solve the coordinated operation strategy of the electricity and natural gas networks considering the demand characteristics of DESs and EUs.In the HMOGTA,a hierarchical Stackelberg game model is developed for generating equilibrium strategies of DESs and EUs in each district energy network(DEN).Based on the game results,we obtain the coupling demand constraints of electricity and natural gas(CDCENs)which reflect the relationship between the amounts and prices of electricity and cooling(E&C)that DESs purchase from utility networks.Furthermore,the minimization of conflicting costs of E&G networks considering the CDCENs are solved by a multi-objective optimization method.A case study is conducted on a test IES composed of a 20-node natural gas network,a modified IEEE 30-bus system,and 3 DENs,which verifies the effectiveness of the proposed HMOGTA to realize fair treatment for all participants in the IES.

The effect of oxygen concentration on the coupled neurons:Rich spiking patterns and synchronization

The dynamical microenvironments play a crucial role in neuronal spiking patterns.In this paper,we investigated the effect of oxygen concentration on different synchronous spiking patterns of two coupled neuron models by including dynamical ion concentration.Two coupling modes of electrical diffusive coupling and potassium diffusive coupling were considered.In these two cases,oxygen concentration exhibited an important role in the synchronous spiking patterns between two coupled neurons,and extremely rich electrical activities were observed.For the potassium diffusive coupling,differential synchronous patterns of oscillation state(OS),synchronous epileptic seizure state(SSZ)and synchronous spreading depression state(SSD)as well as SZ and SD bursting states were generated.For the electrical diffusive coupling,differential synchronous patterns of resting state(RS),SSZ and SSD were observed.