Influence Of Constant Electric Field Research Articles

Влияние тока, ограниченного объемным зарядом, на диэлектрические свойства поликристаллических пленок фуллерита С-=SUB=-60-=/SUB=-

In the frequency range from 30 Hz to 1 MHz, the dielectric properties of polycrystalline fullerite films with a thickness of about 300 nm, which are part of p-type Si / C60 / InGa structures, were studied under the influence of constant electric fields with a strength of up to 33 MV / m. It was found that at negative polarity of the InGa electrode, when the injection of electrons from the metal into the fullerite is facilitated, at frequencies less than 1000 Hz, an anomalous increase in the electrical capacity of the sample is observed, while the capacitance at a low frequency exceeds the capacitance at a high frequency by more than 1000 times. An explanation for this effect is proposed.

Experimental determination of the influence of a constant electric field on the output of biogas and substrate varieties

Оbjective. To investigate the effectiveness of stimulation of biogas release from cow substrate under influence of constant electric field of certain tension at mesophilic temperature regime. Methodology. Experimental research based on a laboratory biogas plant consisting of two reactors housed inside a thermostat and connected to gas-holder system to determine its volume and chemical composition. One of the reactors is equipped with a system of exposure to substrate by constant electric field. The optimum intensity of electric field was determined by previous experiments. The research was performed on a cow's substrate under mesophilic regimen and included determination of the dynamics of biogas output, changes in its chemical composition, and overall degree of dry organic matter destruction. Findings. The research has shown that biogas output per unit of dry organic matter under influence of constant electric field increased by 11.3%, the destruction of the latter increased by 12.2%, and the total volume of biogas (excluding CO2) increased by 8, 2%. It should also be noted that the lag phase was reduced by 12.2%. Originality. Complex research of influence of constant electric field on biomethanogenesis with measurement of chemical composition of obtained biogas and determination of degree of dry organic matter destruction has not been conducted before. Practicalvalue. The work allowed us to conclude that the influence of constante lectric field of certain intensity really stimulates the process of biogas production, without significantly affecting its composition. This method of biome-?hanogenesis intensification can be applied in industrial plants to increase their efficiency. Keywords: biogas, biomethanogenesis, bioenergy, biogasplant, chemical composition

Electrical field control of magnetoelectric effect in composite structures with single crystal piezoelectrics

The influence of constant electric field on the characteristics of the direct magnetoelectric effect in composite structures with single crystal piezoelectric layers was observed. The effect was measured in the structures with langatate and catangasite piezoelectric layers and amorphous magnetic alloy metglas as a ferromagnetic layer. The value of magnetoelectric voltage coefficient of 146 V/(Oe·cm) was obtained for the langatate-based structure and value of 1.35 V/(Oe·cm) for the catangasite-based structure. For the langatate-metglas structure, electrical field of 20 kV/cm resulted in a change in the generated voltage up to 63%, in the quality factor Q up to 76%, and provided linear variation of the resonance frequency up to 16 Hz. Electrical field control of magnetoelectric effect characteristics can be used to design new magnetoelectric devices.

Hierarchical structures of functionalized multi–walled carbon nanotubes in aerosil solution

The features and regularities of self−assembly and self− organization processes in the diffusion−limited conditions (method of drops) of aqueous (deionized water) colloidal solutions of multi−walled carbon nanotubes with aerosil under the influence of constant electric fields with a value varying of direct current voltage from 15 to 25 V have been studied. During droplet evaporation in an electric field, the processes of hierarchical structuring have been studied and the formation of linear piecewise with the sizes of 40—120 nm, fractal structures 25—45 nm and diffusion structures 250 nm from MWCNT — COOH + aerosil + H 2 O DI have been observed. These structures have been analyzed by methods of confocal microscopy, X−ray powder diffraction, Raman scattering, atomic force microscopy, FT−IR spectroscopy and scanning electron microscopy. The size of micro− and nanostructures in hyperbolic dependence of d = 1/U in the approximation d → 2R, and their growth rate increases as U 2 have been observed. Intensive ultrasonic dispersion proves to produce a centrally−axial arrangement located SWCNT after ultrasonic dispersing of functionalized MWCNT — COOH + aerosil + H 2 O DI colloidal solution, as confirmed by excitation of Raman lines in the low−wavelength region, the so−called breathing mode, resulting in the existence of mixed types sp 2 −hybridization with π− and σ−carbon bonds, as well as metallic and semiconducting conductivity, which indicates great practical importance of this structuring for the development of nanoelectronics.

Investigation of the structure, thermomechanical and sorption properties of crosslinked polyacrylamide films formed under the influence of constant electric field

Investigation of the structure, thermomechanical and sorption properties of crosslinked polyacrylamide films formed under the influence of constant electric field

Phase transition in ellipsoidal droplets of nematic liquid crystals

We developed a simple method for the calculation of the director field distribution in the droplets of nematic liquid crystals (LCs) of any shape, allowing for the interaction of LCs with the droplet surface, as well as the influence of constant electric field. In contrast to different approaches, the approach that is developed in the present paper does not require any simplifying suppositions about the structure of the LC director field. The elastic-continuum theory is used, complemented with the possibility of consideration of point and linear defects. Calculations are performed using the Monte Carlo method on a simple grid. The triangulation technique is used to take the boundary conditions of droplets of a complex shape into account. The developed approach can be used for investigation of the properties of polymer-dispersed liquid crystals (PDLCs). The topological phase transitions in the nematic LC 4-cyano-4′-pentyl-biphenyl (5CB) in spherical and ellipsoidal droplets are investigated in this paper.

Influence of constant electric field on circular photogalvanic effect in material with Rashba Hamiltonian

An appearance of a direct current perpendicularly to a constant component of an electric field in material with Rashba Hamiltonian under the influence of an elliptically polarized wave is investigated in one-subband approximation. On its physical nature this effect is close to a circular photogalvanic effect (CPGE) on intraband transitions. The effect is studied on the base of two approaches: investigations of Boltzmann kinetic equation in a constant collision frequency approximation and semiclassical Monte Carlo simulations, which immediately takes into account microscopic processes of charge carriers scattering on optical and acoustical phonons. Monte Carlo modelling allows us to determine a mean relaxation time and its dependencies on electric field strengths and on the energy of optical phonons. On the base of these estimations a possibility of using a constant relaxation time approximation is justified. It is confirmed that the main contribution to the effects of transverse rectification is made by inelastic scattering of electrons on optical phonons. A comparison of results of Monte Carlo simulations and calculations on the base of a constant collision frequency approximation is presented.

Influence of constant electric field on generation of higher harmonics in semiconductor carbon nanotubes

The generation of higher harmonics by semiconductor carbon nanotubes in the presence of constant electric field polarized along the nanotube axis is considered. The analysis is performed in the semiclassical model of electron motion without taking into account interband transitions. The electron system of carbon nanotubes is described using the kinetic Boltzmann equation in the relaxation time approximation. The dependence of higher harmonic amplitude on the field characteristics is studied.

The influence of constant electric field on relaxation processes due to the interaction of domain boundaries and mobile point defects in TGS

The dependencies of relaxation times τ1 and τ2 at constant electric field in TGS crystals were observed.

Influence of constant electric field on self-propagating high-temperature synthesis wave

A model of a heterogeneous medium allowing the action of a constant electric field (CEF) on a combustion wave in the condensed phase to be taken into account is proposed. It is shown that the influence of the CEF on the combustion temperature is of threshold type: At a CEF less than the threshold, the combustion temperature is constant; above the threshold, the combustion temperature falls with increase in CEF. The combustion rate falls with increase in CEF; this is associated with slowing of the reactive diffusion in the combustion wave. On passing through the CEF threshold, there is a discontinuity in the combustion-rate curve; this is due to additional slowing of the reactive diffusion on account of the reduction in combustion temperature.