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1.
A study of the structure of electrohydrodynamic flows shows that the electric charge carriers are ions that are practically
frozen into the surrounding liquid. In other words, ions in weakly conducting liquids are capable of forming more or less
stable structures whose viscoelastic properties are different from those of an uncharged liquid. One method of studying this
effect is to investigate the velocity dispersion of ultrasound on charged supermolecular formations. The results of theoretical
and experimental investigations of acoustic dispersion in liquid dielectrics subjected to prebreakdown electric fields are
presented. A model problem of sound propagation in a liquid in which supermolecular structures have formed around elementary
charge carriers is studied theoretically. Approximate formulas describing the dispersion of the acoustic phase velocity as
a function of the electric field parameters and the electrophysical parameters of the liquid are obtained. The frequency dependence
of the sound velocity is of a resonance character, the resonance frequency being determined by the electric charge density
and the mass of the charged supermolecular structures. The experiments showed that the space charge affects the velocity of
acoustic waves in liquid dielectrics.
Zh. Tekh. Fiz. 67, 105–111 (October 1997) 相似文献
2.
We propose a model for an electric field-induced transition from an ordered phase of the lattice–gas system with alternating charges to a disordered phase. We assume the hopping conductivity of charge carriers. The analysis of this model using Monte Carlo method demonstrates that sufficiently high electric field can disorder ordered phases inducing flow of charges in a system with blocked conduction pathways. 相似文献
3.
4.
An investigation is made of electric fields induced in natural dielectrics by mechanical loading and electrical polarization.
It is shown that the relaxation of the polarization is identical in nature for both cases and is basically a thermally activated
process. The temperature dependence is obtained for the relaxation time of the electric fields. Also estimated is the activation
energy for motion of charge carriers leading to the relaxation of these fields.
Fiz. Tverd. Tela (St. Petersburg) 39, 1202–1204 (July 1997) 相似文献
5.
F. Jansson A.V. Nenashev S.D. Baranovskii F. Gebhard R.
sterbacka 《Annalen der Physik》2009,18(12):856-862
The effect of electric field on diffusion of charge carriers in disordered materials is studied by Monte Carlo computer simulations and analytical calculations. It is shown how an electric field enhances the diffusion coefficient in the hopping transport mode. The enhancement essentially depends on the temperature and on the energy scale of the disorder potential. It is shown that in one‐dimensional hopping the diffusion coefficient depends linearly on the electric field, while for hopping in three dimensions the dependence is quadratic. 相似文献
6.
V. A. Harutyunyan 《Physics of the Solid State》2010,52(8):1744-1749
The single-electron states in a quantized cylindrical layer in the presence of a strong homogeneous electric field have been
considered in the isotropic effective mass approximation. The energy spectrum and the envelope wave functions of charge carriers
in the layer have been obtained in the explicit form. It has been shown that a strong external electric field leads to an
additional localization of carriers in their angular motion. The corresponding selection rules have been derived, and the
absorption band of intraband-intersubband optical transitions in the layer has been calculated. 相似文献
7.
V. S. Kuznetsov 《Russian Physics Journal》1991,34(10):906-912
The quantization of the current carriers and the effect of an electric field in the space charge region on Tamm surface states are investigated within the framework of the Kronig-Penney model and in the effective mass approximation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 70–77, October, 1991. 相似文献
8.
J. Parisi U. Rau J. Peinke K. M. Mayer 《Zeitschrift für Physik B Condensed Matter》1988,72(2):225-233
Conductivity and Hall-effect measurements were performed on single-crystallinep-doped germanium, electrically driven into low-temperature avalanche breakdown via impurity impact ionization. The electric transport properties were determined as a function of the applied electric field in the pre- and post-breakdown regime. The characteristic field dependence of the carrier density, mobility, and drift velocity was found to be reflected in smooth variations of the integral current flow. The breakdown mechanism was demonstrated to involve a mobility which sensitively depends upon the density of the mobile charge carriers. Our experimental findings are qualitatively explained by simple model approaches developed from established breakdown theories. 相似文献
9.
利用美国国家强风暴实验室(NSSL)发展的耦合了详细起电机制和放电过程的中尺度电耦合数值模式WRF(weather research forecasting)-Elec,在NSSL云微物理双参数化方案中增加了电场力对霰、雹粒子降落末速度的影响,完善了WRF-Elec模式的物理过程,建立了双向耦合WRF-Elec模式.利用改进后的WRF-Elec模式,通过敏感性数值实验,定量分析了雷暴云内电场力对起电和电荷结构的反馈作用.结果发现:雷暴云发展旺盛阶段,由于电场力作用,霰、雹粒子质量加权平均降落末速度的瞬时变化极值可以超过4 m/s,但这种情况仅出现在雷暴云内局部区域,并且维持时间较短;电场力对直径小且数浓度较低的霰和雹粒子影响较大,但这种影响不是由单一物理量决定,而是由电场强度和霰、雹粒子的电荷密度、极性以及粒子的直径与数浓度共同决定;电场力通过对霰、雹粒子降落末速度的调整,增强了雷暴云内感应、非感应起电率,且前者远大于后者,云内局部产生-0.6—1.2 n C/m~3总电荷密度的变化,从而使电荷结构重新分布,局部垂直电场强度增强5 k V/m,总闪电数增加,与此同时,雷暴云内降水粒子的微观增长过程也发生改变.总体上,电场力对雷暴云起电过程的作用为正反馈,电场力对雷暴云电荷结构的反馈作用不可忽略. 相似文献
10.
《Journal of Electrostatics》2014,72(4):252-260
In this paper, space charge dynamics under DC electric field of −100 kV/mm in low-density polyethylene (LDPE) and its nanocomposite containing a small amount of MgO nanoparticles were measured using an improved pulsed electro-acoustic (PEA) system. Unlike negative packet-like space charge accumulating in LDPE films, no remarkable space charge was observed in LDPE/MgO nanocomposite films, which indicated that the introduction of MgO nanoparticles played a key role on the space charge suppression. Different with current qualitative models, this paper describes space charge suppression on the basis of simulation using the bipolar charge transport model, which featured bipolar charges injection, transport, trapping, recombination, and extraction process. It was shown from the simulation that trap depth, trap concentration, local electric field and charge injection barrier height were all significant factors on the space charge suppression process. A deeper trap depth in LDPE/MgO nanocomposites made it easier for traps to capture mobile carriers. And a larger trap concentration effectively slowed down the whole carrier movement although there seemed a trap concentration threshold less than 30 Cm−3, above which this effect became slight. In addition, both the high permittivity of LDPE/MgO nanocomposites and low local electric field in the vicinity of cathode led to a larger injection barrier height based on the Schottky injection law, which would tremendously block the charge injection. At last, the suppression mechanism of space charge formation in the LDPE/MgO nanocomposites is presented. 相似文献
11.
The paper reports effect of interaction between AC electric field and metal cluster sitting at tip end of the carbon nanotube (CNT) on CNT tip-growth in CVD theoretically. For this purpose, a theoretical model based on phonon oscillations of the metal catalyst and influence of AC electric field on these oscillations is presented. Results show that there is an optimum AC electric field which optimizes growth of ultra-long CNTs. Then it is demonstrated that, in comparison with CNTs in the absence of field, CNTs under optimum electric field grow more. In addition, relation between optimum temperature and amplitude of AC electric field is investigated and it is shown that increasing electric field leads to higher optimum temperature. Finally, Investigation of effect of catalyst type on optimum electric field demonstrates the optimum field for various catalysts is different due to their different characteristics including van der Waals interaction with carbon, atomic mass and number of free charge carriers per each atom. All results are discussed and interpreted. 相似文献
12.
The dynamical processes of the electric charge injection and transport from a metal electrode to the copolymer are investigated by using a nonadiabatic dynamic approach. The simulations are performed within the framework of an extended version of the one-dimensional Su-Schrieffer-Heeger (SSH) tight-binding model. It is found that the electric charge can be injected into the copolymer by increasing the applied voltage. For different structures of the copolymer, the critical voltage biases are different and the motion of the injected electric charge in the copolymer varies obviously. For the copolymer with a barrier-well-barrier configuration, the injected electric charge forms a wave packet due to the strong electron-lattice interaction in the barrier, then comes into the well and will be confined in it under a weak electric field. Under a medium electric field, the electric charge can go across the interface of two homopolymers and enter into the other potential barrier. For the copolymer with a well-barrier-well configuration, only under strong enough electric field can the electric charge transfer from the potential well into the barrier and ultimately reach a dynamic balance. 相似文献
13.
《Journal of Electrostatics》2014,72(5):387-395
In this work, analysis of the human body exposed to high voltage electric and magnetic fields is presented. The distribution of the electric field is obtained by using Laplace's equation. This relates the surface charge induced on the body to the potential in a reciprocal Laplace problem, which is then calculated by charge simulation method coupled with genetic algorithms to determine the appropriate arrangement of simulating charges inside the human body. The magnetic field intensity along the vertical center line of the human is calculated. Exposure to external electric and magnetic fields at power frequency induces electric field, magnetic field and currents inside the human body. The presented model for simulating electric and magnetic fields are a three dimensional field problem and introduced different types of charges to simulate the different elementary geometrical shapes of human body. The particular strength of the charge simulation method in this application is its ability to allow a detailed representation of the shape and posture of the human body. The results have been assessed through comparison induced current, electric field, magnetic field and there distribution over the body surface, as estimated in other experimental and computational work. 相似文献
14.
Spin-polarized injection and transport into ferromagnetic/organic semiconductor structure are studied theoretically in the presence of the external electric field and magnetic induction. Based on the spin-drift-diffusion theory and Ohm's law, we obtain the charge current polarization, which takes into account the special carriers of organic semiconductors. From the calculation, it is found that the current spin polarization is enhanced by several orders of magnitude by tuning the magnetic induction and electric fields. To get an apparent current spin polarization, the effects of spin-depended interfacial resistances and the special carriers in the organic semiconductor, which are polarons and bipolarons, are also discussed. 相似文献
15.
N. A. Gusak 《Technical Physics》2014,59(4):540-545
Specific features of space-charge gratings excited in photorefractive crystals in the presence of an external variable electric field that exhibits power-law time dependence are studied. It is demonstrated that the process under study substantially depends on a parameter of an increase in the external electric field over a time interval that corresponds to the generation of space-charge gratings in the absence of the field. At a relatively small parameter, the charge can be increased in accordance with variations in the field, charge oscillations with increasing amplitude can be induced, and identical excitation of the gratings can be maintained. At a relatively large parameter, the charge of the gratings is proportional to the time of external action, so that the charge can be controlled using external variable electric field. 相似文献
16.
Behaviour of the quasi-one-dimensional Peierls insulator (PI) with a doubled lattice period (of the trans-polyacetylene type) is studied in the uniform electric field The electric field polarizes the insulator thus decreasing the gap Δ in the quasiparticle spectrum and creates by tunnelling charge carriers pairs. Depending on the field strength direct creation of soliton-antisoliton pairs or electron-hole pairs (e-h) takes place. The (e-h) pairs deform the lattice forming polarons. For the cis-type polyacetylene the superinsulator phase with soliton confinement exists. The latter is characterized by a great number of soliton-antisoliton quantum levels. Because of the charges generation the process of insulator-to-metal transition becomes continuous. 相似文献
17.
The effect of transverse entrainment of charge carriers by two electromagnetic waves propagating in mutually perpendicular directions in a semiconductor with a parabolic dispersion law has been investigated. The dc component of the electric current density that appears in the direction perpendicular to the wave vectors has been calculated in the constant relaxation time approximation. It has been shown that the transverse dc current vanishes at a particular phase difference of the incident waves determined by the relaxation time of charge carriers in the material. 相似文献
18.
B. P. Gorshunov M. L. Shupegin V. Yu. Ivanov A. S. Prokhorov I. E. Spektor A. A. Volkov 《Technical Physics》2008,53(5):641-645
IR spectra of metal-containing diamondlike silicon-carbon films are taken for the first time. It is shown that the optical
response from the subsystem of free charge carriers in chromium-containing films can be described in terms of a simple model
that deals with carriers localized inside clusters several nanometers in size. The data obtained indicate that the electric
and dielectric properties of the films can be controlled by technological means during their synthesis and by varying the
size, concentration, and conductivity of metallic nanoclusters. 相似文献
19.
S. Sh. Rekhviashvili Murat O. Mamchuev Mukhtar O. Mamchuev 《Physics of the Solid State》2016,58(4):788-791
A new theoretical (semiempirical) model of diffusion-drift charge carrier transport in layers with a fractal structure based on a partial differential equation with a fractional time derivative has been proposed. It has been shown by numerical calculations that a decrease in the order of the fractional derivative in the presence of the external electric field leads to broadening and asymmetry of the spatial distributions of charge carriers, which physically corresponds to intensification of scattering processes. 相似文献
20.
Studying the charge carrier properties in CuInS_2 films via femtosecond transient absorption and nanosecond transient photocurrents
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《中国物理 B》2019,(5)
The carrier behavior in CuInS_2 thin films at femtosecond and microsecond time scales is discussed in detail. Transient absorption data suggests that the photo-generated carriers relax rapidly accompanied by a change in energy. The photogenerated charge carriers are extracted by a bias electric field E in the nanosecond transient photocurrent system. An applied E improves the efficiency of photon conversion to charge carriers and enhances the velocity of the extracted charge carriers. In addition, there exists a threshold of illumination intensity in the extraction process of charge carriers in the CuInS_2 thin film, above which carrier recombination occurs. The corresponding loss further increases with illumination intensity and the recombination rate is almost independent of E. Our results provide useful insights into the characteristics of carriers in the CuInS_2 thin film and are important for the operation of optoelectronic devices realized with these films. 相似文献