Action Of External Electric Field Research Articles

Control of iron(II)-tris(2,2'-bipyridine) light-induced excited-state trapping via external electromagnetic fields.

Light-induced excited spin-state trapping reactions in iron pyridinic complexes allow the iron's low-to-high spin transition in a sub-picosecond timescale. Employing a recently developed model for [Fe(2,2'-bipyridine)3]2+photochemical spin-crossover reaction in conjunction with quantum wavepacket dynamics, we explore the possibility of controlling the reaction through external electromagnetic fields, aiming at stabilizing the initial metal-to-ligand charge transfer states. We show that simple Gaussian-shaped electromagnetic fields have a minor effect on the population kinetics. However, introducing vibrationally excited initial wavepacket representations allow to maintain trapped the population into the metal-to-ligand charge transfer states. Using optimal control theory, we propose an electromagnetic field shape that increases the lifetime of metal-to-ligand charge transfer states. These results open the route for controlling the iron photochemistry through the action of external electric fields.

Electroosmotic flow and heat transfer characteristics of a class of biofluids in microchannels at high Zeta potential

Peristalsis is an important dynamic phenomenon in the field of biomedical research, and has great application prospects in microscale fluids. In recent years, this biomimetic (peristaltic) phenomenon has gained widespread attention due to its large-scale applications in various medical and industrial fields, such as radiation therapy, peristaltic blood pumps, and drug delivery systems. In this study, the electroosmotic flow and heat transfer characteristics are investigated under high wall Zeta potential and slip boundary conditions for a certain type of biological fluid that satisfies the Newtonian fluid model. Fluid flows under the joint action of external electric field, magnetic field, and Joule heating. Firstly, without using the Debye-Hückel linear approximation, the numerical solutions are given by using the Chebyshev spectral method for the nonlinear Poisson-Boltzmann equation, the fourth-order differential equation satisfied by the stream function, and the thermal energy equation. The results are compared with those obtained by using the Debye-Hückel linear approximation to demonstrate the effectiveness of the numerical method used in this study. Secondly, the effects of wall Zeta potential, Hartmann number <inline-formula><tex-math id="M11">\begin{document}$H$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M11.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M11.png"/></alternatives></inline-formula>, electroosmotic parameter <inline-formula><tex-math id="M12">\begin{document}$m$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M12.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M12.png"/></alternatives></inline-formula>, slip parameter <inline-formula><tex-math id="M13">\begin{document}$\beta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M13.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M13.png"/></alternatives></inline-formula> are discussed on the flow characteristics, peristaltic pumping, and trapping phenomena under electromagnetic environments, and the influence of Joule heating parameter <inline-formula><tex-math id="M14">\begin{document}$\gamma $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M14.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M14.png"/></alternatives></inline-formula> and Brinkman number <inline-formula><tex-math id="M15">\begin{document}$Br$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M15.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M15.png"/></alternatives></inline-formula> is explored on heat transfer characteristics. The results show that 1) wall Zeta potential plays an important role in controlling the velocity of fluid peristaltic flow; 2) the increase of electroosmotic parameter <inline-formula><tex-math id="M16">\begin{document}$m$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M16.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M16.png"/></alternatives></inline-formula> and slip parameter <inline-formula><tex-math id="M17">\begin{document}$\beta $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M17.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M17.png"/></alternatives></inline-formula> increases the flow velocity in the central region of the channel, while the increase of Hartmann number <inline-formula><tex-math id="M18">\begin{document}$H$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M18.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M18.png"/></alternatives></inline-formula> hinders the flow of fluid; 3) these flow behaviors exhibit opposite trends near the channel walls; 4) the number of streamlines captured by peristaltic transport decreases with Hartmann number <inline-formula><tex-math id="M19">\begin{document}$H$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M19.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M19.png"/></alternatives></inline-formula> and electroosmotic parameter <inline-formula><tex-math id="M20">\begin{document}$m$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M20.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M20.png"/></alternatives></inline-formula> increasing; 5) the increase of Joule heating parameter <inline-formula><tex-math id="M21">\begin{document}$\gamma $\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M21.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M21.png"/></alternatives></inline-formula> and Brinkman number <inline-formula><tex-math id="M22">\begin{document}$Br$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M22.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="6-20231685_M22.png"/></alternatives></inline-formula> leads temperature to rise.

Instability of liquid film with odd viscosity and slip effect under the action of external electric field

The influence of odd viscosity on the instability of a liquid film flowing along a porous inclined plane under a normal electric field is investigated. It is assumed that the flow at the porous inclined plane satisfies the Beavers–Joseph slip boundary condition. By utilizing the long-wave approximation and employing the method of systematic asymptotic expansion, a nonlinear evolution equation for the film thickness under the influence of the electric field is derived. The stability analysis of this evolution equation reveals that the odd viscosity of the film has a stabilizing effect, while the electric field has a destabilizing effect. Additionally, the permeability of the porous inclined plane enhances the instability of the liquid film flow. Numerical simulations are conducted using a fast Fourier transform algorithm to solve the nonlinear evolution equations. The numerical results demonstrate that, within the stable region and with all parameters fixed, the wave amplitude decreases as the evolution time increases, indicating a gradual stabilization of the liquid film flow. Conversely, in the unstable region, the opposite behavior is observed. As the evolution time increases, the fluctuation amplitude grows larger, resulting in a gradual destabilization of the liquid film flow. Furthermore, when the evolution time is kept constant and the odd viscosity coefficient is nonzero, the film exhibits greater stability. The amplitude of the wave increases with the electrical parameter E. In the unstable region, an increase in the permeability β of the porous medium leads to a tendency for the film flow to stabilize.

Electric field effect of sliding graphene/hexagonal boron nitride heterobilayer

The first-principles computer-aided design of atomistic heterostructures can discover the physical properties of new materials and help them widely find applications in frontier scientific fields. Here, we report an investigation on the heterobilayer composed of one sheet of two-dimensional (2D) graphene on the surface of one-layer hexagonal boron nitride (h-BN). We calculate and simulate the binding energies, electric dipoles related to interlayer sliding, and twisting angles of three stacking orders in graphene/hBN heterobilayer. The relative energies of these three heterobilayers are obtained by using first-principles calculations method and the AB stacking structure exhibits the lowest energy. We have also found that the electric field perpendicular to the 2D plane can control the dipole magnitude of the bilayer system, and even change the polarization direction. We studied the kinetic stability of graphene-hBN bilayer heterostructures under the action of external electric fields using Ab initio molecular dynamics (AIMD), as well as the thermodynamic stability. Finally, we propose that the graphene/h-BN heterobilayer might play an important role in the field of information electronics as a 2D material with interesting physical properties.

780 nm near-infrared photorefractive holograms recorded in undoped Bi12TiO20 crystal under the action of external electric field

In this paper, we studied recording and erasure of photorefractive holographic gratings recorded at 780 nm in an undoped Bi12TiO20 (BTO) crystal sample under the action of an externally applied electric field. The diffraction efficiency was measured by directly chopping the diffracted beams by the gratings recorded in a two-wave mixing setup without using of any phase-modulation technique of the recording beams or feedback mechanism. An enhancement of 3.5-fold in the diffraction efficiency was observed when the applied electric field increased from 0 to 6 kV/cm. The theoretical dependence of the diffraction efficiency on the external electric field considering the effect of screening of charges near the electrodes was investigated, and the result is supported by good fit to the experimental data, allowing us to compute characteristic parameters of the material, including the values of photoactive donor concentrations (ND1)eff ≈ 0.12 × 1016 cm−3 and (ND2)eff ≈ 0.8 × 1015 cm−3, respectively, for the levels placed at 1.6 eV and 1.3 eV below the conduction band responsible for photorefractive recording in the BTO sample.

Study on the dissociation properties and spectra of chlorodifluoromethane under an external electric field

Chlorodifluoromethane (HCFC-22) is a kind of greenhouse gas, the study of its properties and dissociation methods is of great value to reduce its pollution. Based on the density functional theory (DFT), the structure, spectra and dissociation characteristics of HCFC-22 gas molecules under applied electric field (0 V·nm−1–12.856 V·nm−1) are discussed at the 6–311 G++ (d, p) level. The results all show that HCFC-22 molecule is more easily dissociated under an external electric field. The dissociation characteristic of the molecule is as follow: the dissociation barrier decreases gradually with the increase of external electric field. In addition, the UV–Vis spectrum of HCFC-22 is redshifted and the excitation energy decreases gradually under the action of external electric field. The results of this study provide theoretical support for the application of electric field to degrade HCFC-22 molecules, which can help solve the problem of air pollution.

Synthesis, molecular dynamics and dielectric properties of benzoic acid intercalated kaolinite

The synthesis of new clay-organic nanocomposites with potential application value is one of the research hotspots in the field of functional materials. Herein, benzoic acid intercalated kaolinite compound (K-BzCOOH, calculated as Al 2 Si 2 O 5 (OH) 4 ·(BzCOOH) 0.556 , d (001) of 1.419 nm, and 51.5% intercalation rate) was synthesized, and its preparation methods, intercalation mechanisms and dielectric properties were investigated thoroughly. The results show that K-BzCOOH must be obtained under high pressure with K-DMSO as the precursor and methanol as the solvent. The benzoic acid molecules are arranged in an inclined monolayer between kaolinite layers, and benzene ring and the center of gravity of benzoic acid molecules are close to the surface of alumina layer. Hydrogen bonds are mainly present between H(Al-sheet) and O(c=o), and between H(coo-h) and O(Si-sheet).The interfacial interaction between inorganic and organic components is -47.11 kJ/mol. Dielectric measurements show that K-BzCOOH exhibits relaxation behavior in the range of 1-10 7 Hz and 10-100°C, attributed to the limited dipole motion of benzoic acid molecules under the action of external electric field. Also, the compound has a low dielectric constant at frequencies greater than 10 6 Hz (6.9 and 8.8 at 10°C and 100°C, respectively), which can be considered as a low- k material for semiconductor industry. • K-BzCOOH (Al 2 Si 2 O 5 (OH) 4 ·(BzCOOH) 0.556 ) was first prepared. • Intercalation mechanism probed by molecular dynamics. • K-BzCOOH exhibits two dielectric relaxation processes and low dielectric constant.

6,6]CNB with controllable external electric field deformation: a theoretical study of the structure-function relationship

An external electric field (EEF) has a strong controlling effect on the structure, electron distribution, and optoelectronic properties of a system. In this study, the geometric structure, electronic distribution and electronic transition properties of [6,6]carbon nanobelt ([6,6]CNB) were investigated under different EEFs based on density functional theory and wave function analysis. These theoretical studies determined that EEF can significantly change the geometry of [6,6]CNB by elongating its structure. The system deformation was mainly caused by forces pulling in the direction of the EEF. After removal of the EEF, the system reverted to its original structure. Electronic polarization played a major role in structural stability during the deformation process. The changes in geometric structure and electronic distribution affected the photoelectric properties of [6,6]CNB. Under the action of EEFs, the absorption peak of [6,6]CNB was red-shifted and gradually appeared in the visible light region. This study facilitates an understanding of the performance of [6,6]CNB as a new type of nanomaterial and provides the necessary theoretical basis for the application of [6,6]CNB in the field of optoelectronics.

Modelling of multi-species transport in concrete under the action of external electric field: Influence of the overpotential at electrode–electrolyte interfaces

• A model describing ionic transport with electrostatic potential effect is presented. • Overpotential at electrodes during ionic transport are examined and demonstrated. • Interaction of ionic transport and electrostatic action is described and demonstrated. • Effects of various processing parameters on ionic transport in concrete are discussed. • Transient chloride binding mechanism is discussed and illustrated. The application of external electrical field on concrete structures is widely used to protect it from chloride attack or to evaluate its resistance to chloride penetration in a short period. During these electrochemical processes, the polarization of electrodes placed inside and/or outside of concrete cannot be ignored. This study proposes a numerical model dealing with the mass transport and electrode polarizing process under an externally applied voltage, in which multi-species electromigration, time-varying overpotential and non-equilibrium binding are involved. The Tafel Equation is adopted to express the overpotential at electrode–electrolyte interfaces. The electro-potential boundary changing with overpotential is reset at each time step to obtain the accurate concentration distributions of ionic species. Additionally, benchmarks against third-party experiments are conducted to verify the reliability of the present model. The effects of externally applied voltage, Tafel parameters and initial ionic species concentration on the interaction of overpotential and chloride penetration are also quantitatively examined. The obtained results show that the potential difference between two concrete surfaces is always lower than that applied on electrodes due to the influence of polarization, which has a further impact on the temporal and spatial concentration distributions of ionic species in the pore solution of concrete.

Effects of Bi<sub>2</sub>Te<sub>3</sub>(111) and Al<sub>2</sub>O<sub>3</sub>(0001) substrates on electronic and topological properties of Bi(111) bilayer

The bilayer and thin films of Bi(111) have demonstrated novel topological properties. Here, we investigate the electronic structures of Bi/Bi<sub>2</sub>Te<sub>3</sub>(111) and Bi/Al<sub>2</sub>O<sub>3</sub>(0001) by combining first-principles and tight-binding approximation calculations. Our results show that the Bi(111) bilayer is a semiconductor with a gap of about 0.2 eV. Its electronic states are strongly disturbed by the interaction with Bi<sub>2</sub>Te<sub>3</sub>(111) thin films, no matter whether the substrate has a band gap or Dirac surface state. Moreover, it is hard to see Rashba-type band splittings in such systems. In contrast, it demonstrates clean and giant Rashba-type splittings as strongly hybridized with insulating Al<sub>2</sub>O<sub>3</sub>(0001), which is due to the broken inversion symmetry induced by interfacing and the strong atomic spin-orbit coupling in Bi. Our tight-binding approximation analyses further reveal that the effect of substrate Al<sub>2</sub>O<sub>3</sub>(0001) on the band structure of the Bi(111) bilayer is equivalent to the action of external electric field in a range between 0.5 and 0.6 V/Å. Moreover, we find that the strong hybridization between Bi(111) bilayer and the electronic state of the substrate Bi<sub>2</sub>Te<sub>3</sub>(111) can lead to a topological phase transition, i.e. the change from a two-dimensional topological insulator into a mediocre insulator. Our study thus provides an insight into the interface-engineering of electronic states of Bi(111) bilayer.

First-principle investigation of Li–N dual-acceptor co-doping for p type ZnO: The effect of electric fields

Obtaining stable P-type ZnO is the key and bottleneck of its industrialization application in LED field. In this paper, a new electrostatic field-assisted semiconductor doping method is proposed, which can effectively reduce the formation energy of Li–N dual-acceptor P-type ZnO defects, thus greatly improving the solid solubility of Li–N defects. We use the First-principle calculations based on Density Functional Theory, research defect formation energy, density of states, electron density and population analysis of Li–N co-doped ZnO under electrostatic field. The calculation results show that the higher electric field intensity, the more formation energy reduces and the greatest reduction will be in the parallel direction, up to 0.52120HA. Therefore, Li–N co-doping under the action of external electric field can obtain more stable p-ZnO. The analysis of the distribution of charge density difference indicates that the electronic clouds' overlapping effect in the Li–N defect sphere is the main factor that leads to the reduction of formation energy. The investigation provides a theoretical reference for study of ZnO-based p-type semiconductor materials with higher carrier's density.

Study on microscale flow characteristics of electrorheological Fluids

Electrorheological fluid is a kind of intelligent material whose rheological properties change rapidly and reversibly under the action of external electric field, It has a broad prospect in practical engineering application. It is found in the research progress of electrorheological fluids. The time scale and space scale of the electrorheological effect are very small, and the flow process has some micro-scale flow characteristics. In this paper, the dynamics of dielectric particles in electrorheological fluids under static and dynamic coupling fields is numerically simulated by dissipative particle dynamics method. The influence of surface force under static field on the submicrostructure of Electrorheological fluid and the influence of electroviscosity under dynamic coupled field on the flow rate of Electrorheological fluid are also studied.

Synergistic Effects of External Electric Field and Solvent Vapor Annealing with Different Polarities to Enhance β-Phase and Carrier Mobility of the Poly(9,9-dioctylfluorene) Films

In this work, the synergistic effects of external electric field(EEF) and solvent vapor annealing to enhance β-phase and carrier mobility of poly(9,9-dioctylfluorene)(PFO) films were investigated. It is found that EEF can promote the PFO β-phase conformation transition and orientate the PFO chains along the EEF direction with the assistance of polar solvent vapor annealing. PFO chain orderness is closely related to the solvent polarity. In particular, the β-phase content in the annealed film of strong polar chloroform vapor increases from 18.7% to 34.9% after EEF treatment. Meanwhile a characteristic needle-like crystal is formed in the film, as a result, the hole mobility is enhanced by an order of magnitude. The mechanism can be attributed to the fast polarization of solvent dipole under the action of EEF, thus forming a driving force that greatly facilitates the orientation of PFO dipole unit. Research also reveals that EEF driving of the PFO chains does not occur with an insoluble solvent vapor since the solvent molecules cannot swell the film, thus there is insufficient free volume for PFO chains to adjust their conformation. This research enriches the understanding of the relationship between solvent vapor annealing and EEF in orientation polymers, and this method is simple and controlled, and capable of integrating into large-area thin film process, which provides new insights to manufacture low-cost and highly ordered polymer films, and is of great significance to enhance carrier mobility and efficiency of photoelectric devices based on polymer condensed matter physics.

INTENSITY OF ELECTRIC FIELD UNDER OVERHEAD POWER LINE USING CATENARY SHAPE OF CONDUCTORS

<p><span lang="EN-US"><strong><span style="font-family: Times New Roman; font-size: small;">This </span></strong></span><span lang="EN-GB"><strong><span style="font-family: Times New Roman; font-size: small;">article presents a superposition method in combination with the Coulomb’s law and the Method of image charges for calculation of the electric field distribution generated by high voltage overhead power lines above a flat surface in every dimension. Such calculations are required to ensure the operational safety of people exposed to the action of external electric field as well as to reduce the cost of people protection. The method provides options for calculation of the field around the wire of a general shape. This substantial improvement of the method could be applied to eliminate the usual error in the calculation created using approximation of catenary shape conductors by infinite straight conductors. The method has been extensively tested on a set of shapes with known analytical solutions. It has been shown that the numerical solution converges uniformly to the analytical solution and the accuracy depends only on the number of finite elements.</span></strong></span></p>

Photon-enhanced thermionic emission solar energy converters with GaAs wire array cathode under external electric field

In this work, a theoretical emission model for GaAs wire array cathode based on photon-enhanced thermionic emission (PETE) under the action of external electric field is deduced utilizing two-dimensional continuity equations. With the electron energy distribution and elevation angle of emitted electron considered, the electron collection probability for each emission surface of GaAs wire array cathode varying with the field intensity is simulated. Combining emission current density with electron collection probability, the effective collection current density of GaAs wire array cathode is obtained. Results suggest that the external electric field can effectively enhance the collection probability of emitted electrons within GaAs wire array, which contributes to the improvement of the actual photoelectric conversion capability of GaAs wire array cathodes. For GaAs wire array cathodes, the effective collection current density can reach the maximum value with the incident angle of 20° and field intensity of 0.9 V/μm. Applying a transparent phosphorus-doped diamond film as the anode material, the simulated conversion efficiency increases from 18.85 to 44.80% as the electron affinity of GaAs wire cathode rises from 0 to 0.6 eV.

Structure and properties of nanoscale Ag2S/Ag heterostructure

Ag2S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. The formation of Ag2S/Ag nanocomposite structures is confirmed by X-ray analysis, high-resolution electron microscopy, and energy dispersion analysis. It is established that in the contact layer between silver sulfide and silver, nonconductingα-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag heteronanostructure is proposed.

Facile synthesis, structure, and properties of Ag2S/Ag heteronanostructure

Ag2S/Ag heteronanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag2S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The size of Ag2S and Ag nanoparticles is 45–50 and 15–20 nm, respectively. It is established that in the contact layer between silver sulfide and silver, nonconducting α-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag heteronanostructure is proposed. The UV–Vis optical absorption spectra of colloidal solutions of Ag2S/Ag heteronanostructures have been studied.

STRUCTURE AND PROPERTIES OF AG2S/AG SEMICONDUCTOR/METAL HETERONANOSTRUCTURE

Ag2S/Ag hetero-nanostructure has been produced by a simple one-stage chemical deposition from aqueous solutions of silver nitrate, sodium sulfide, and sodium citrate with the use of monochromatic light irradiation. For simultaneous synthesis of Ag2S and Ag nanoparticles, deposition has been performed from reaction mixtures with reduced sodium sulfide concentration. The formation of Ag2S/Ag nanocomposite structures is confirmed by X-ray analysis, high-resolution electron microscopy, energy dispersion analysis and dynamic light scattering methods. It is established that in the contact layer between silver sulfide and silver, non conducting α-Ag2S acanthite transforms into superionic β-Ag2S argentite under the action of external electric field. The scheme of the operation of a resistive switch based on an Ag2S/Ag hetero-nanostructure is proposed.

Particle charging mechanism and numerical methodology for industrial applications

Particles in industrial flows can be charged under an action of external electric field, while in the absence of external electric field, tribo-electrostatic charges are almost unavoidable in gas-solid two-phase flows due to the consecutive particle contacts. The particle charging may be beneficial, or detrimental. In the past decade considerable progress has been made in understanding the physics of particles charging. However, the particle charging mechanism, especially in the gas-solid phase flow, is still poorly understood. The purpose of this review is to present a clear understanding of the particle charging and movement of charged particle in two-phase flow, by summarizing the charging mechanisms, physical models of particle charging, and methods of charging/charged particle entrained fluid flow simulations. In this review, charged particles in industry, which would be beneficial (triboelectrostatic separation, electrostatic precipitator) or detrimental (electrification in gas-solid fluidized bed and manufacturing plant) are discussed separately. The particle charging through collisions could be attributed to electron transfer, ion transfer, material transfer, and/or aqueous ion shift on particle surfaces. For conductive particle contacts, the difference in work function is often used to explain the charge transfer. For insulation particle contacts, the charging tendency can be explained by the ion transfer and material transfer. In addition, aqueous ion shift transfer would be an important charge transfer mechanism considering water content in environmental conditions and the influences of temperature and humidity. The charges on particle through collision can be quantitatively predicted by using the particle charging model. According to the differently induced ways of charge transfer, the charging models are related to the external electric field, asymmetry contact, and/or aqueous ion shift on particle surfaces. In fact, the motions of particles in industry are influenced by fluid flow. The effect of fluid on particle dynamics makes the particle charging more complicated. Thus it is more reasonable to study the particle charging from the viewpoint of the gas-solid two-phase flow. The method combining particle charging model with computational fluid dynamics and discrete element method is applicable to the studying of the particle charging/charged processes in gas-solid two phase flow in which the charge behaviors are significantly influenced by the fluid mechanics behavior. By this method, the influence factors of particle charging, such as gas-particle interaction, contact force, contact area, and various velocities, are described systematically. This review presents a clear understanding of the particle charging and provides theoretical references on controlling and utilizing the charging/charged particles in industrial technology.

Clusters Formation in Salts Solution in Polar Dielectric Liquids and Electrically-induced Separation of Solvated Ions

The aim of study is to demonstrate that separation of solvated ions in solution of mix of salts under the action of external periodic electric field happens because of around ions there are formed clusters consisting of molecules of solvent and the sizes of such clusters have dimensions ~ 0.1 μm. In investigations the sizes of clusters theoretically were defined and experimentally value of frequency of external electric field which action excites the effect of separation of the solvated ions was defined. Experiments were done in the Technical Physics Chair of the National Research Tomsk Polytechnic University. At theoretical determination of the dimensions of clusters Poisson's equation was solved and was considered that polar molecules of solvent are oriented under the action of electric field of an ion. The chemical composition of samples of solutions was determined by means of the X-ray excited fluorescent radiation analysis method. Theoretical estimates and results of experiments confirmed the assumption that clusters which are formed around ions in solutions have the dimensions ~ 0.1 μm. Results of investigation testify that placing of volume distributed electric charge of ion in Original Research Article British Journal of Applied Science & Technology, 4(18): 2014 2539 dielectric liquid is accompanied by formation of the supramolecular particles, which we called “clusters”, linear sizes of which is significantly more than first and second radiuses of solvation (~ 1 Angstrom) and reach size ~ 0.1 μm. At such sizes inertial properties of clusters and their natural frequencies give the chance to operate their movement by means of action of external electric field on solution.