BLOCH DYNAMICS IN SPATIALLY LOCAL INHOMOGENEOUS ELECTRIC FIELDS

2001 ◽  
Vol 11 (02) ◽  
pp. 425-453
Author(s):  
JOSEPH P. REYNOLDS ◽  
GERALD J. IAFRATE ◽  
JUN HE
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Nearest Neighbor ◽  
Constant Electric Field ◽  
Tight Binding ◽  
Homogeneous Field ◽  
Wannier Functions ◽  
Field Dependent ◽  
Bloch Electrons ◽  
Special Case

The influence of local inhomogeneities on the electric field dependent properties of Bloch electrons is studied. The homogeneous electric field is described through the use of the vector potential, and the instantaneous Wannier functions of the homogeneous field dependent Hamiltonian are used as bases states to depict Bloch dynamics and properties. Model examples are treated using Slater-Koster inhomogeneities and nearest-neighbor tight-binding band structure in a one dimensional, single-band analysis. Detailed analysis is presented for the special case of a constant electric field; here the influence of localization due to the presence of the electric field is shown to clearly affect the energy spectrum of the Bloch electron for a single and double impurity configuration.

Electronic structure of POPC phospholipids under constant electric field

2017 ◽  
Vol 31 (22) ◽  
pp. 1750157
Author(s):  
Jaciéli Evangelho de Figueiredo ◽  
Leandro Barros da Silva
Keyword(s):  
Electronic Structure ◽  
Dipole Moment ◽  
External Field ◽  
Electric Field ◽  
Electric Fields ◽  
Electric Dipole Moment ◽  
Electric Dipole ◽  
Constant Electric Field ◽  
Ab Initio Study ◽  
Electronic And Structural Properties

We report in the present paper an ab initio study on the electronic and structural properties of phospholipidic membranes under the influence of electric fields. We show that the external field alters the charge distribution of the molecule leading to a modification in the electric dipole moment. The torque on the phospholipid may then cause a transmembranar stress, which by its turn, weakens the membrane allowing to the formation of a pore.

scholarly journals ELECTROPHORESIS IN THE TOTAL (CONSTANT AND ALTERNATING) ELECTRIC FIELD. II. PECULIARITIES OF THE COMBINED IMPACT OF ALTERNATING AND CONSTANT ELECTRIC FIELDS

2020 ◽  
Vol 30 (4) ◽  
pp. 46-51
Author(s):  
B. P. Sharfarets ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Electrokinetic Phenomena ◽  
Alternating Electric Fields ◽  
Alternating Electric Field ◽  
Electroacoustic Transducer ◽  
Dispersed Medium ◽  
Hydrodynamic Field ◽  
Combined Impact

The hydrodynamics of electrophoresis under the simultaneous impact of constant and alternating electric fields is considered. It has been shown that when the constant and alternating external fields are combined, the energy of the constant electric field is transferred into the alternating hydrodynamic field. An example is given of a dispersed medium in which a giant dispersion of the dielectric constant can arise, which in turn can contribute to an increase in the total electrophoresis rate. Analogies of the behavior of the considered dispersed medium with the action of an electroacoustic transducer based on the use of electrokinetic phenomena are given.

THE IMPROVEMENT OF THE HIGH VOLTAGE TESTING METHOD

2019 ◽  
pp. 4-14
Author(s):  
V. A. Syasko ◽  
S. S. Golubev ◽  
A. S. Musikhin
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Homogeneous Field ◽  
Inhomogeneous Field ◽  
Minimum Thickness ◽  
Air Gaps ◽  
Testing Method ◽  
Almost All

The high voltage spark testing method of protective dielectric coatings is applied in almost all manufacture areas and is governed by ISO, ASTM etc. However, all of it doesn’t pay proper attention to high voltage forming (DC or AC) and its polarity relative to electrode, influence of environment and electric field inhomogeneity. In that paper a detailed analysis of air gap breakdown forming processes was given. A dependence of electric field strength on an interelectrode gap length was given for homogeneous and highly inhomogeneous electric fields. It was shown a breakdown voltage of air gaps in highly inhomogeneous field is greatly less than in homogeneous field. Also, it is described the breakdown voltage of air gaps with positive polarity is less then with negative polarity. The possibility coatings testing with a minimum thickness up to 50 m while reducing the testing voltage without reducing the reliability of the results is shown.

Linear AC transport in T-stub and crossed silicene nanosystems

2018 ◽  
Vol 32 (03) ◽  
pp. 1850016
Author(s):  
Yun-Lei Sun ◽  
En-Jia Ye
Keyword(s):  
Electric Field ◽  
Transport Properties ◽  
External Electric Field ◽  
Nearest Neighbor ◽  
Transport Theory ◽  
Energy Gap ◽  
Local Density ◽  
Tight Binding ◽  
Edge State ◽  
Topological Quantum

In this work, we theoretically study the linear AC transport properties in T-stub and crossed zigzag silicene nanosystems. The DC conductance and AC emittance are numerically calculated based on the tight-binding approach and AC transport theory, by considering the nearest-neighbor hopping, second-nearest-neighbor spin-orbit interaction (SOI) and external electric field. The relatively strong SOI of silicene was demonstrated to induce a topological quantum edge state in the nanosystems by the local density of states, which eliminates the AC emittance response at the Dirac point. Further investigations suggest that the SOI-induced AC transport is topologically protected from the changes of geometrical size. Moreover, the AC transport properties of these nanosystems can be tuned by the external electric field, which would open an energy gap and destroy the topological quantum state, making them trivial band insulators.

scholarly journals Multiphoton intersubband transitions in an armchair graphene nanoribbon

2021 ◽  
Vol 2103 (1) ◽  
pp. 012130
Author(s):  
B S Monozon ◽  
T A Fedorova ◽  
P Schmelcher
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Graphene Nanoribbon ◽  
Laser Technique ◽  
Strong Light ◽  
Vacuum Decay ◽  
Experimental Values ◽  
Armchair Graphene Nanoribbon ◽  
Armchair Graphene

Abstract We present an analytical approach to the problem of the interband transitions in an armchair graphene nanoribbon (AGNR), exposed to the time-periodic electric field of strong light wave, polarized parallel to the ribbon axis. The two-dimensional Dirac equation for the massless electron subject to the ribbon confinement is employed. In the resonant approximation the probability of the transitions between the valence and conduction size-quantized subbands are calculated in an explicit form. We trace the dependencies of the Rabi frequency for these transitions on the ribbon width and electric field strength for both the multiphoton-assisted and tunneling regimes relevant to the fast oscillating and practically constant electric field, respectively. Estimates of the expected experimental values for the typically employed AGNR and laser technique facilities show that the Rabi oscillations can be observed under laboratory conditions. The data, corresponding to the intersubband tunneling, makes the AGNR a 1D condensed matter analog, in which the quantum electrodynamic vacuum decay can be detected by the employment of the attainable electric fields.

Numerical simulation of the leaky dielectric microdroplet generation in electric fields

2016 ◽  
Vol 27 (01) ◽  
pp. 1650012 ◽  
Author(s):  
Reza Kamali ◽  
Mohammad Karim Dehghan Manshadi
Keyword(s):  
Biological Sciences ◽  
Field Strength ◽  
Electric Field ◽  
Electric Field Strength ◽  
Electric Fields ◽  
Constant Electric Field ◽  
Fluid Volume ◽  
Dielectric Fluids ◽  
Leaky Dielectric ◽  
Vast Range

Microdroplet generation has a vast range of applications in the chemical, biomedical, and biological sciences. Several devices are applied to produce microdroplets, such as Co-flow, T-junction and Flow-focusing. The important point in the producing process is controlling the separated fluid volume in these devices. On the other hand, a large number of liquids, especially aqueous one, are influenced by electric or magnetic fields. As a consequence, an electric field could be used in order to affect the separated fluid volume. In this study, effects of an electric field on the microdroplet generation in a Co-flow device are investigated numerically. Furthermore, effects of some electrical properties such as permittivity on the separating process of microdroplets are studied. Leaky dielectric and perfect dielectric models are used in this investigation. According to the results, in the microdroplet generating process, leaky dielectric fluids show different behaviors, when an electric field is applied to the device. In other words, in a constant electric field strength, the volume of generated microdroplets can increase or decrease, in comparison with the condition without the electric field. However, for perfect dielectric fluids, droplet volume always decreases with increasing the electric field strength. In order to validate the numerical method of this study, deformation of a leaky dielectric droplet in an electric field is investigated. Results are compared with Taylor theoretical model.

Research Progress on the Electric Coagulation of Fine Dust

2014 ◽  
Vol 955-959 ◽  
pp. 2594-2599
Author(s):  
Ruo Bai Ma ◽  
Kai Quan Wang ◽  
Hai Pu Bi
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Collection Efficiency ◽  
Constant Electric Field ◽  
Research Progress ◽  
Charged Dust ◽  
Fine Dust ◽  
Dust Collection ◽  
Advantages And Disadvantages ◽  
Dust Collection Efficiency

Fine dust in the atmosphere is one of the key factors causing air pollution as well as fog and haze. Due to the limited efficiency of fine dust collection in conventional dust removal technology, pre-charged dust coagulation between particles to increase the effective collecting diameter, is an effective way to improve the dust collection efficiency. Currently, coagulation technology research falls into three mainly aspects: electric coagulation technology in constant electric field, alternating electric field and pulsed electric fields. The advantages and disadvantages as well as the research status and trends are fully analyzed in this paper, of which the technology that uses alternating or pulsed power supply for pre-charge device has more advantages and efficiency in coagulation. They will improve the efficiency of electric coagulation in further on the improved airflow pole with form and structure and the technical development of alternating or pulsed powers, which will make the coagulation and filtration technologies and new composite technology an important development direction of fine dust governance.

Conductivity of impurity graphene nanoribbons and gate electric field

2017 ◽  
Vol 31 (36) ◽  
pp. 1750340
Author(s):  
Natalia Konobeeva ◽  
Mikhail Belonenko
Keyword(s):  
Electric Field ◽  
Graphene Nanoribbons ◽  
Constant Electric Field ◽  
Tight Binding ◽  
Tunneling Current ◽  
Graphene Nanoribbon ◽  
Voltage Characteristic ◽  
Current Voltage Characteristic ◽  
Tight Binding Approximation ◽  
Current Voltage

In this paper, we investigate the influence of a gate electric field on the tunneling current for the contact of impurity graphene nanoribbon with a metal or quantum dots. Based on the Hamiltonian for graphene in the tight-binding approximation, the density of states is calculated, which allows us to obtain a tunneling current. We analyze the effect of the field magnitude on the detecting possibility of an impurity in the graphene nanoribbon. A sufficient change of current–voltage characteristic (CVC) of the contact is observed, with an increase in the constant electric field applied parallel to the nanoribbon plane.

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