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.

Constructing Built-In Electric Fields with Semiconductor Junctions and Schottky Junctions Based on Mo-MXene/Mo-Metal Sulfides for Electromagnetic Response

The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave(EMW)absorption materials.However,the loss mechanism in traditional heterostructures is relatively simple,guided by empirical observations,and is not monotonous.In this work,we presented a novel semiconductor-semiconductor-metal heterostructure sys-tem,Mo-MXene/Mo-metal sulfides(metal=Sn,Fe,Mn,Co,Ni,Zn,and Cu),including semiconductor junctions and Mott-Schottky junctions.By skillfully combining these distinct functional components(Mo-MXene,MoS_(2),metal sulfides),we can engineer a multiple heterogeneous interface with superior absorption capabilities,broad effective absorption bandwidths,and ultrathin matching thickness.The successful establishment of semiconductor-semiconductor-metal heterostructures gives rise to a built-in electric field that intensifies electron transfer,as confirmed by density functional theory,which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption.We detailed a successful synthesis of a series of Mo-MXene/Mo-metal sulfides featuring both semiconductor-semiconductor and semiconductor-metal interfaces.The achievements were most pronounced in Mo-MXene/Mo-Sn sulfide,which achieved remarkable reflection loss values of-70.6 dB at a matching thickness of only 1.885 mm.Radar cross-section calculations indicate that these MXene/Mo-metal sulfides have tremendous potential in practical military stealth technology.This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities.

Analysis of the axial electric field in a plasma-loaded- helix travelling wave tube

A helix type slow wave structure filled with plasma is immersed in a strong longitudinal magnetic field. Taking into account the effect of the plasma and the dielectric, the system is separated radially into three regions. By means of the sheath model and Maxwell equation, the distribution of the electromagnetic field is established. Using the boundary conditions of each region, the dispersion relation of the slow wave structure is derived. The trend of change for the radial profile of the axial electric field is analysed respectively in different plasma densities, plasma column radius and dielectric constant by numerical computation. Some useful results are obtained on the basis of the discussion.

Effect of aging in an electric field on microstructures and properties of 1420 Al-Li alloy

After solution treatment, the 1420 Al-Li alloy samples were aged at different temperatures in an electric field with different intensity. The measurements made showed that the electric field increased the strength of the 1420 Al-Li alloy, and best properties were obtained when they were aged at 120 ℃ with E=4 kV/cm for 12 hrs. The electric field promoted the nucleation of δ′ phase, increased the quantity of the δ′ phase, and made the size of the δ′ phase particles smaller. The electric field restrained the formation and growth of PFZ, and increased the intensity of the electric field while the width of the PFZ was decreased.

Excitation-wavelength-dependent THz wave modulation via external bias electric field

A theoretical model was proposed to describe the effects of external bias electric field on terahertz(THz)generated in air plasma.The model predicted that for a plasma in a bias electric field,the amplification effect of the THz wave intensity increases with the increase of the excitation laser wavelength.We experimentally observed the relationship between the THz enhancement effect and the electric field strength at different wavelengths.Experimental results showed a good agreement with the model predictions.These results enhance our understanding of the physical mechanism by which femtosecond lasers excite air to generate THz and extend the practical applications of THz generation and modulation.

Bifurcation mechanism of interfacial electrohydrodynamicgravity-capillary waves near the minimum phase speed under ahorizontal electric field

We investigate the evolution of interfacial gravity-capillary waves propagating along the interface be-tween two dielectric fluids under the action of a horizontal electric field.There is a uniform backgroundflow in each layer,and the relative motion tends to induce Kelvin-Helmholtz(KH)instability.The com-bined effects of gravity,surface tension and electrically induced forces are all taken into account.Underthe short-wave assumption,the expansion and truncation method of Dirichlet-Neumann(DN)operatorsis applied to derive a reduced dynamical model.When KH instability is suppressed linearly by a consider-ably large electric field,our numerical results reveal that in certain regions of parameter space,nonlinearsymmetric traveling wave solutions can be found near the minimum phase speed.Additionally,the de-tailed bifurcation structures are presented together with typical wave profiles.

Theoretical Study on Drift of Ca^(2+)Spiral Waves Controlled by Electric Field

Based on the Tang-Othmer Ca^2＋ model, the drift behavior of intracellular Ca^2＋ spiral waves under the influence of weak electric field is investigated. Numerical results show that the dependence of drift velocity of the spiral tip on dc electric field is similar to experimental observations in BZ system. When an ac electric field is applied, interesting resonant-drift phenomenon is observed with ω=2ω0. All results can be explained analytically using a proximate method.

HIGH PERFORMANCE ELECTRIC FIELD MICRO SENSOR WITH COMBINED DIFFERENTIAL STRUCTURE

This paper presents a high performance electric field micro sensor with combined differential structure.The sensor consists of two backward laid micro-machined chips,each packaged by polymer and metal.The novel combined differential structure effectively reduces various environmental affections,such as thermal drift,humidity drift and electrostatic charge accumulation.The sensor is tested in near-ground place as well as balloon-borne sounding.In different weather conditions,the measurement results showed good agreement with those of the commercial electric field mill.

EFFECT OF A WEAK LONGITUDINAL ELECTRIC FIELD ON WHISTLER WAVES

The effect of a longitudinal electric field on whistler waves is studied based onkinetic theory.A local Maxwellian distribution is taken as stationary distribution function ofelectrons which departs from thermodynamic equilibrium due to the applied electric field.Thedielectric tensor is derived by integrating along orbit of the particle in the unperturbed field.Dispersion relation and growth rate are analysed from Hermitian and anti-Hermitian parts ofthis tensor respectively.It is found that the waves are growing when the angle between the wavevector and the electric field is in range of θ【2θ_c, otherwise the whistler waves are damping.Thegrowth rate increases with wave frequency and decreases with the angle between the wave vectorand the applied field.In the case of ω_e(?)Ω the maximum of growth rate,which is at θ=O_l isproportional to the plasma density and anti-proportional to the magnetic field.Some computedresults for parameters at top of the F layer are given.

Evolution of spiral wave and pattern formation in a vortical polarized electric field

In this paper, the evolution of the pattern transition induced by the vortical electric field （VEF） is investigated. Firstly, a scheme is suggested to generate the VEF by changing the spatial magnetic field. Secondly, the VEF is imposed on the whole medium, and the evolutions of the spiral wave and the spatiotemporal chaos are investigated by using the numerical simulation. The result confirms that the drift and the breakup of the spiral wave and the new net-like pattern are observed when different polarized fields are imposed on the whole medium respectively. Finally, the pattern transition induced by the polarized field is discussed theoretically.

Off-Shore Sea Surface Electric Field Investigations around the Indian Sub-Continent during 9-20 May 1983

Sea surface electric field observations off the coast from Goa (15°25'N, 73°47'E) to Madras (13°04'N, 80°15'E) around Sri Lanka, in a distance range 25-135 km from coast, during 9-20 May 1983 were taken. In this paper we have examined the diurnal variation of electric field in the Arabian Sea, Indian Ocean and Bay of Bengal regions covered during the cruise of the research ship ORV Gaveshani. An aspect of electric field dependence on coastal distance and Aitken Nuclei concentration has also been studied. An attempt to examine the latitude dependence of field was also made. Results obtained in the above studies are presented and compared with those obtained elsewhere.

Variations in the Atmospheric Electric Field at Tropical Station during 1930-1987

The variations noticed in the atmospheric electric field recorded at Pune (18°32'N, 73°51'E, 559 m ASL), a tropical inland station located in Dcccan Plateau, India, during the period 1930-1987, have been examined in relation to the variations observed in the Angstrom turbidity coefficient (β) and selected meteorological parameters. The monthly and annual mean values of the atmospheric electric field. Angstrom turbidity coefficient (β), rainfall, temperature and relative humidity for the years 1930-1938, 1957-1958, 1964-1965, 1973-1974 and 1987 were considered in the study.The results of the above study indicated gradual increases in the atmospheric electric field over the period of study (1930-1987) which is statistically significant at less than 5%level. The increases noticed during different periods varied from 30 to 109%. The increase noticed during the period (1930-1938) and (1973-1974) was maximum (109%). The Angstrom turbidity coefficient also showed systematic increases during the period of study, which is consistent. The diurnal curve of the atmospheric electric field at the station by and large, showed a double oscillation, which is generally observed in the conlinental environments.

ELECTRIC FIELD MICROSENSOR BASED ON THE STRUCTURE OF PIEZOELECTRIC INTERDIGITATED CANTILEVER BEAMS

This paper presents the design, fabrication, and preliminary experimental result of an electric field microsensor based on the structure of piezoelectric interdigitated cantilevers with staggered vertical vibration mode. The working principle of this electric field microsensor is demonstrated, and the induced charges and structural parameters of this microsensor are simulated by the finite element method. The electric field microsensor was fabricated by Micro-Electro Mechanical Systems(MEMS) technique. Each cantilever is a multilayer compound structure(Al/Si3N4/ Pt/PZT/Pt/ Ti/SiO 2/Si), and Piezoelectric, PieZ oelectric ceramic Transducer(PZT)(PbZ rxTi(1–x)O3) layer, prepared by sol-gel method, is used as the piezoelectric material to drive the cantilevers vibrating. This electric field microsensor was tested under the DC electric field with the field intensity from 0 to 5×104 V/m. The output voltage signal of the electric field microsensor has a good linear relationship to the intensity of applied electric field. The performance could be improved with the optimized design of structure, and reformative fabrication processes of PZT material.

Simulation of GaN micro-structured neutron detectors for improving electrical properties

Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different methods such as the method of modulating the trench depth,the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region(W).It is observed that the intensity of electric field can be modulated by scaling the trench depth.On the other hand,the electron blocking region is formed in the detector enveloped with a dielectric layer.Furthermore,the introducing of p-type inversion region produces new p/n junction,which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction.It can be realized that all these methods can considerably enhance the working voltage as well as W.Of them,the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8μm when the carrier concentration of p-type inversion region is 10^17 cm^-3.Consequently,the value of W is observed to improve 200%for the designed GaN-MSND as compared with that without additional design.This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.

Effects of aging in electric field on 2024 alloy

The effect of heat treatment in an electric field on micro plastic deformation characteristics of 2024 Al alloy was investigated. The mechanism of aging in an electric field affecting the micro plastic deformation behavior was preliminarily discussed. The results show that the resistance to micro plastic deformation of the alloy can be greatly increased by aging in an electric field. Aging temperature, aging time and electric field strength are selected by adopting the orthogonal design method and the optimum technological parameters are obtained.

The residual zonal flow in tokamak plasmas with a poloidal electric field

In a tokamak plasma with auxiliary heating by cyclotron waves, a poloidal electric field will be produced, and as a consequence influence the residual zonal flow(RZF) level. The poloidal electric field can also be induced through biasing electrodes at the edge region of tokamaks.Numerical evaluation for a large aspect ratio circular cross section tokamak for the electron cyclotron wave heating indicates that the RZF level decreases significantly when the poloidal electric field increases. Qualitatively, the ion cyclotron wave heating is able to increase the RZF level. It is difficult to apply the calculation to the real cyclotron wave heating experiments since we need to know factors such as the plasma profiles, the exact power deposition and the cross section geometry, etc. It is possible to use the cyclotron wave heating to control the zonal flow and then to control the turbulence level in tokamak experiments.

Experimental study and theoretical analysis on the effect of electric field on gas explosion and its propagation

The effect of the electric field with different intensity on explosion wave pressure and flame propagation velocity of gas explosion was experimentally studied, and the effect of electric field on gas explosion and its propagation was theoretically analyzed from heat transportation, mass transportation, and reaction process of gas explosion. The results show that the electric field can affect gas explosion by enhancing explosion intensity and explosion pressure, thus increasing flame velocity. The electric field can offer energy to the gas explosion reaction; the effect of the electric field on gas explosion increases with the increase of electric field intensity. The electric field can increase mass transfer action, heat transfer action, convection effects, diffusion coefficient, and the reaction system entropy, which make the turbulence of gas explosion in electric field increase; therefore, the electric field can improve flame combustion velocity and flame propagation velocity, release more energy, increase shock wave energy, and then promote the gas explosion and its propagation.

A Model for Periodic Nonlinear Electric Field Structures in Space Plasmas

In this study,we present a physical model to explain the generation mechanism of nonlinear periodic waveswith a large amplitude electric field structures propagating obliquely and exactly parallel to the magnetic field.The'Sagdeev potential' from the MHD equations is derived and the nonlinear electric field waveforms are obtained when theMach number,direction of propagation,and the initial electric field satisfy certain plasma conditions.For the parallelpropagation,the amplitude of the electric field waves with ion-acoustic mode increases with the increase of initial electricfield and Mach number but its frequency decreases with the increase of Mach number.The amplitude and frequency ofthe electric field waves with ion-cyclotron mode decrease with the increase of Mach number and become less spiky,andits amplitude increases with the increase of initial electric field.For the oblique propagation,only periodic electric fieldwave with an ion-cyclotron mode obtained,its amplitude and frequency increase with the increase of Mach number andbecome spiky.From our model the electric field structures show periodic,spiky,and saw-tooth behaviours correspondingto different plasma conditions.

Micro-seismic wave's propagation law and its numerical simulation

Deduced the propagation rule of longitudinal and transverse wave. On the basis of this, propagation rules in attenuated visco-elastic media and varied Lame coefficient were put forward as well. The subsequent numerical analysis found that in a small scope longitudinal and transverse wave could be considered as homogeneously propagating when faultages and joints were not taken into account. The existence of lane hindered the wave＇s propagation, and it made the velocity gradient change in a local vicinity area. Therefore velocity varied in different direction.

Diffusion Equations of the Electric Charges and Magnetic Flux

Innovative definitions of the electric and magnetic diffusivities through conducting mediums and innovative diffusion equations of the electric charges and magnetic flux are verified in this article. Such innovations depend on the analogy of the governing laws of diffusion of the thermal, electrical, and magnetic energies and newly defined natures of the electric charges and magnetic flux as energy, or as electromagnetic waves, that have electric and magnetic potentials. The introduced diffusion equations of the electric charges and magnetic flux involve Laplacian operator and the introduced diffusivities. Both equations are applied to determine the electric and magnetic fields in conductors as the heat diffusion equation which is applied to determine the thermal field in steady and unsteady heat diffusion conditions. The use of electric networks for experimental modeling of thermal networks represents sufficient proof of similarity of the diffusion equations of both fields. By analysis of the diffusion phenomena of the three considered modes of energy transfer;the rates of flow of these energies are found to be directly proportional to the gradient of their volumetric concentration, or density, and the proportionality constants in such relations are the diffusivity of each energy. Such analysis leads also to find proportionality relations between the potentials of such energies and their volumetric concentrations. Validity of the introduced diffusion equations is verified by correspondence their solutions to the measurement results of the electric and magnetic fields in microwave ovens.