Electric Charge Distribution Research Articles

ACOUSTICS OF PROCESS AS A FACTOR OF FORMING IN THE COMBUSTION ZONE OF FORMATIONS WITH EXCESS CHARGE

The nature and mechanism of formation and reproduction in time of macroscopic, fluctuational nature of formations with uncompensated electric charge (aquazineutral or AQN-formations) fixed by observations in the burning zone are investigated. With account of characteristic to combustion acoustic manifestations it is shown, that when burning in the reacting medium are necessarily developed instabilities in the distribution of electrical charge over the volume.It is substantiated, that the excitation conditions and the general features of charge instabilities in distribution of charge over volume really determine the mechanism under study as factor jointly providing of both the formation and continuous reproduction of AQN-formations in the combustion zone (in the pre-flame region, first of all).

Numerical Study of the Suitable Precharger Grounded Electrode Length in Two-Stage-Type Electrostatic Precipitators

The two-stage-type electrostatic precipitator has been used only in limited applications because of its need to accommodate a large flow rate with its compact size. A two-stage-type electrostatic precipitator comprises a precharger and a collecting unit. The grounded electrode in the precharger is generally designed to be quite short. Previous studies on the influence of the grounded electrode length in the precharger on collection efficiency have reported that the amount of particle charge through the precharger decreases for grounded electrodes that are 20- or 80-mm long. The electric field and space charge distributions were calculated for various grounded electrode lengths using the finite-element method, where the ion density distribution was used as the space charge distribution. For a 20-mm-long grounded electrode, the electric field intensity around the high-voltage wire electrode decreased. Additionally, the electric field intensity distribution at close proximity to the grounded electrode has two additional peaks due to the edges of the electrode. With the 80-mm-long grounded electrode, the peaks of the electric field intensity distribution were outside of the high-ion-density region. These results show that the optimal grounded electrode length for particle charging is about three times the distance between the grounded electrode and the high-voltage wire electrode.

Double Fano resonance in gold nanotube embedded with a concentric elliptical cylinder

Optical properties of the concentric composite nanostructure composed of gold nanotube around the center gold elliptical core are investigated based on the finite difference time domain method. According to the simulated absorption and scattering spectra, electric field distributions and charge distributions, we can generate double dipole-dipole Fano resonances by adjusting the angle between the elliptical cylinder core and the linearly polarized excitation light, which is due mainly to the interference between the subradiant dipole mode and the superradiant dipole mode. The narrow, low-energy subradiant mode originates from the symmetric hybrization between the longitudinal or transverse dipole mode of the elliptical cylinder core and the dipole bonding mode of the nanotube, and the broad, high-energy superradiant mode originates from the symmetric hybrization between the core’s dipole mode and the nanotube’s dipole antibonding mode. Moreover, the intensities and spectral positions of the two Fano resonances can be manipulated by modifying the geometric parameters of the composite structure. By increasing the semiminor axis of elliptical core, the high-energy Fano resonance red-shifts faster than the low-energy Fano resonance due to the increase of the interaction coupling between the transverse dipole mode of the core and the dipole mode of the nanotube, and becomes weaker in the scattering spectrum because of the reduced radiation intensity of the superradiant dipole mode. When the semimajor axis is changed, a similar phenomenon occurs in the low-energy Fano resonance. In addition, the two Fano resonances red-shift when outer radius of the nanotube increases, but the shift of low-frequency and high-frequency Fano resonance are inconsistent as the inner radius of the nanotube changes. The high-frequency Fano resonance red-shifts monotonically while the low-frequency Fano resonance first blue-shifts and then red-shifts with the increase of inner radius of nanotube because the red shift of the dipole bonding nanotube mode competes with the spectral shifts induced by the diminishing hybridization between elliptical core and nanotube mode. It can also be concluded that the dipole-dipole Fano resonances become apparent and higher order Fano resonance occurs when the composite nanostructure is scaled to a larger size due to the increased radiative damping. With the core and nanotube size fixed, Fano resonance is insensitive to the change of the external environment, but has a good response to the nuclear material of the nanotube.

Weak radius of the proton

The weak charge of the proton determines its coupling to the Z0 boson. The distribution of weak charge is found to be dramatically different from the distribution of electric charge. The proton's weak radius RW=1.545±0.017 fm is 80% larger than its charge radius Rch≈0.84 fm because of a very large pion cloud contribution. This large weak radius can be measured with parity violating electron scattering and may provide insight into the structure of the proton, various radiative corrections, and possible strange quark contributions.

Effective Excess Charge Density in Water Saturated Porous Media

A model for the effective excess charge in a capillary as well as in porous media is developed for arbitrary pore scales. The prediction of the model is then compared with another published model that is limited for a thin electric double layer (EDL) assumption. The comparison shows that there is a deviation between two models depending on the ratio of capillary/pore radius and the Debye length. The reasons for the deviation between two models are not only due to the thin EDL assumption to get electrical potential and charge distribution in pores but also to some other approximations for integral evaluations. The results suggest that the model developed in this work can be used with arbitrary capillary/pore scale and thus is not restricted to the thin EDL assumption.
 Keywords: Zeta potential, porous media, electric double layer, effective excess charge.
 References
 [1] M. Aubert, Q.Y. Atangana, Groundwater, 34 (1996) 1010–1016.[2] A. Finizola, J.-F. Lénat, O. Macedo, D. Ramos, J.-C. Thouret, F. Sortino, J. Volcanol. Geoth. Res., 135 (2004) 343–360.[3] C. Doussan, L. Jouniaux, J.-L. Thony, Journal of Hydrology 267 (2002) 173–185.[4] F. Perrier, M. Trique, B. Lorne, J.-P. Avouac, S. Hautot, P. Tarits, Geophys. Res. Lett. 25 (1998) 1955–1958.[5] Martinez-Pagan, P., A. Jardani, A. Revil, and A. Haas, Geophysics 75 (2010) WA17–WA25.[6] Naudet, V., A. Revil, J.-Y. Bottero, and P. Bgassat, Geophysical Research Letters 30 (2003).[7] V. Naudet, M. Lazzari, A. Perrone, A. Loperte, S. Piscitelli, V. Lapenna, Engineering Geology 98 (2008) 156-167.[8] A. Perrone, A. Iannuzzi, V. Lapenna, P. Lorenzo, S. Piscitelli, E. Rizzo, F. Sdao, Journal of Applied Geophysics 56 (2004) 17-29.[9] Jouniaux, L., A. Maineult, V. Naudet, M. Pessel, and P. Sailhac, C. R. Geoscience 341 (2009).[10] Revil, A., and A. Jardani, The Self-Potential Method: Theory and Applications in Environmental Geosciences, Cambridge University Press, 2013.[11] Hunter, R., Zeta Potential in Colloid Science: Principles and Applications, Colloid Science Series, Academic Press, 1981.[12] Leroy, P., and A. Revil, Journal of Colloid and Interface Science, 270 (2004) 371–380.[13] T. Ishido, H. Mizutani, Journal of Geophysical Research 86 (1981) 1763-1775.[14] P. W. J. Glover, E. Walker, M. Jackson, Geophysics 77 (2012) D17–D43.[15] Revil, A., and P. Leroy, Journal of Geophysical Research 109 (2004).[16] Linde, N., D. Jougnot, A. Revil, S. K. Matthäi, T. Arora, D. Renard, and C. Doussan, Geophys. Res. Lett. 34 (2007) L03306.[17] Revil A. and Mahardika H, Water Resources Research 49 (2013) 744–766.[18] Jardani, A., A. Revil, A. Bolève, A. Crespy, J. Dupont, W. Barrash and B. Malama, Geophysical Research Letters, 34 (2007) L24,403.[19] L. Guarracino, D. Jougnot, Journal of Geophysical Research - Solid Earth 123 (2018) 52-65.[20] Jackson M.D., Leinov E., International Journal of Geophysics 2012 (2012).[21] Gierst L., J. Am. Chem. Soc. 88 (1966) 4768.[22] Rice, C., and R. Whitehead, J. Phys. Chem. 69 (1965) 4017–4024.[23] Pride, S., Physical Review B 50 (1994) 15,678–15,696.[24] Bear, J., Dynamics of Fluids in Porous Media, Dover Publications, New York, 1988. [25] Chan I. Chung, Extrusion of Polymers: Theory & Practice, Hanser-2nd edition, 2010.[26] J. Vinogradov, M. Z. Jaafar, M. D. Jackson, Journal of Geophysical Research 115 (2010).

Spectroscopic identification, structural features, Hirshfeld surface analysis and molecular docking studies on stiripentol: An orphan antiepileptic drug

Epilepsy affects approximately 50 million individual worldwide but only 70% thereof are adequately controlled by the clinically used antiepileptic agents. The chemical structure of stiripentol (STP) is significantly different from any other marketed antiepileptic drug and it is approved as an add-on medication to control the childhood epilepsy. Detailed vibrational spectroscopic features of stiripentol aided by density functional theory (DFT) computations have been explored in the current study. Furthermore, the frontier molecular orbital (FMO) analysis, distribution of electric charges on the STP molecule and natural bond orbital (NBO) analysis were investigated using DFT computations. Also, Hirshfeld surface maps of STP and its 2D fingerprint plots were studied to gain insight into different patterns of its intermolecular interactions. Moreover, molecular docking simulations were conducted to manifest the probable binding pose of stiripentol to an anticonvulsant target protein.

Understanding Electric Double-Layer Gating Based on Ionic Liquids: from Nanoscale to Macroscale.

In electric double-layer transistors (EDLTs), it is well known that the EDL formed by ionic liquids (ILs) can induce an ultrahigh carrier density at the semiconductor surface, compared to solid dielectric. However, the mechanism of device performance is still not fully understood, especially at a molecular level. Here, we evaluate the gating performance of amorphous indium gallium zinc oxide (a-IGZO) transistor coupled with a series of imidazolium-based ILs, using an approach combining of molecular dynamics simulation and finite element modeling. Results reveal that the EDL with different ion structures could produce inhomogeneous electric fields at the solid-electrolyte interface, and the heterogeneity of electric field-induced charge distributions at semiconductor surface could reduce the electrical conductance of a-IGZO during gating process. Meanwhile, a resistance network analysis was adopted to bridge the nanoscopic data with the macroscopic transfer characteristics of IL-gated transistor, and showed that our theoretical results could well estimate the gating performance of practical devices. Thereby, our findings could provide both new concepts and modeling techniques for IL-gated transistors.

Electrical Charge Distribution on Carbon Surfaces as a Function of the pH and Point of Zero Charge. An Approximate Solution

Electrical Charge Distribution on Carbon Surfaces as a Function of the pH and Point of Zero Charge. An Approximate Solution

Light Influence on the Sheet Resistance of AlGaN/GaN Heterostructures Grown by MOVPE Technique

AbstractSheet resistance is the most commonly used electrical parameters of thin films; the special feature of sheet resistance is its scalability that is often used in the qualitative assessment of its usefulness. That is why it is so often used as an electrical parameter in the evaluation of created layers by various epitaxial methods. In materials based on AIIIN compounds, there is a built‐in electric field that disturbs the electrical charge inside the heterostructure. The perturbed distribution of electrical charge inside the heterostructure creates donor states on the surface that increase the surface resistance value. The paper presents the influence of UV radiation on surface states affecting the sheet resistance of AlGaN/GaN heterostructures. Based on the presented method, influence of light on sheet resistance is examined and spectral characteristics of AlGaN/GaN heterostructure are obtained. Measurements are performed using the Hall Bar test structure fabricated in AlGaN/GaN heterostructure grown by metal organic vapor phase epitaxy methods. The Hall bar test structures are investigated at room temperature under the light excitation in the range from 280 to 640 nm.

Crosslinked polyethylene/polypyrrole nanocomposites with improved direct current electrical characteristics

Space charge accumulated in insulation materials could result in local field distortion, accelerate the material aging and threaten the security of high voltage direct current (HVDC) cable. To suppress the space charge accumulation and improve the direct current (DC) electrical characteristics of crosslinked polyethylene insulation materials, crosslinked polyethylene/polypyrrole (XLPE/PPy) nanocomposites were prepared, and the DC conduction and breakdown strength were investigated. The XLPE/PPy nanocomposites were characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The DC electrical characteristics measurement results showed that the introduction of nano-polypyrrole (nano-PPy) could reduce the DC electrical conduction current density of XLPE/PPy nanocomposites, improve the space charge distribution but not affect the crosslinking reaction and crystallinity of XLPE. While assuring excellent electrical conduction and space charge distribution characteristics, there was an optimum nano-PPy content to reduce the DC breakdown strength of XLPE/PPy nanocomposites insignificantly.

Study of Dehydrogenation of Pressure-induced NaBH4 Structures Using Calculated NQCC Parameters

Nuclear quadrupole resonance (NQR) spectroscopy is an accurate method for determination of electric charge distribution around quadrupolar nuclei. Using ab initio computational methods, it is possible to calculate the Nuclear Quadrupole Coupling Constants (NQCCs) with high accuracy and obtain the useful structural information by using these parameters. Sodium Borohydride, NaBH4, is a metal hydride complex which is a good candidate for being applied in fuel cells as hydrogen storage material with high capacity of 10.6 wt %. Despite the high capacity of hydrogen storage, hydrogen desorption occurs at high temperatures due to high stability and strong bonds of this compound. This problem limits the practical usage of NaBH4 in fuel cells. One way to overcome this problem is applying the high-pressure techniques and using the pressure-induced NaBH4 structures. Under ambient conditions, NaBH4 has a cubic structure (α-NaBH4) that can be converted to β- and γ-NaBH4 by increasing the pressure. In the present research, charge distribution of α-NaBH4 nanocrystal has been compared to that of high-pressure structures using calculated NQCCs, to study the effect of pressure on different NaBH4 structures and hydrogen desorption ability of them. Our results show the smaller value of 2H–NQCCs and higher value of 11B-NQCCs for β-NaBH4 respect to other structures. In other words, the B-H bond is weaker in β-NaBH4 and it is expected that dehydrogenation occur more feasible and at lower temperature in β-phase compared to other phases. NBO results are in agreement with Calculated NQCCs. Calculations performed using Gaussian 09 program in B3LYP/6-311G*.

Viability of Different Types of Cells Cultivated on the Surface of Medical Electret

The effect of the electric field of a medical electret on the basis of tantalum pentoxide (Ta2O5) on the viability of human fibroblasts, multipotent mesenchymal stromal bone marrow cells, osteocytes, and chondrocytes cultivated on the surface of tantalum orthopedic implants with an electret coating was studied in vitro. Using the methods of photocolorimetic analysis and scanning electron microscopy, difference in the metabolic activity and cell morphology, in the character of the cell attachment to the implants and distribution by their surface, associated with the value and character of the electric charge distribution on the surface of these implants and the type of cellular test systems, were detected. Unclear mechanisms of the effect of the electric field of medical electrets on the functional activity of different types of the organism cell and tissues dictate the need for further experimental developments and fundamental studies in this field.

Finding the Optimized Frequency of Electric Field on the Attempt of Reducing Blood Sugar Level in Type II Diabetes Patients

.

Fully developed mixed convection flow in a vertical channel with electrokinetic effects

Purpose The purpose of this paper is to investigate electrokinetic and mixed convection (pressure gradient and buoyancy) effects on reverse flow formation at the channel walls. Design/methodology/approach The electrical potential distribution was modelled using the Poisson–Boltzmann equation while the governing momentum and energy equations are modelled from the Navier–Stokes equations and solved exactly. Findings It is found that flow reversal at the walls is enhanced by electrokinetic parameter whereas increasing degree of asymmetric parameter up to symmetric heating eliminates reverse flow formation at the walls no matter the electric charge distribution. Originality/value The results of this paper indicate that degree of asymmetric heating, mixed convection parameter and electrokinetic parameter regulate fluid velocity, rate of heat transfer, skin friction and reverse flow formation at the walls.

(Invited) Operando Characterization of Energy Conversion and Storage Devices Using Scanning Probe Microscopy

Energy conversion/storage devices, such as solar cells (SCs) and lithium ion batteries (LIBs), have been actively researched along with the growing interest in energy and environment issues. In order to further improve the performance of these devices, it is essential to have a deeper understanding of their working principles. To achieve this, the characterization of their physical and chemical properties under device operation conditions, so-called operando measurement, is thought to be highly effective. For example, in the case of SCs, important information related with photovoltaic conversion processes can be obtained by measuring the electrical potential, electronic states, and charge distribution in the vicinity of the excitation center under light irradiation conditions. In the case of LIBs, characterization of electrical potential and lithium ion distribution in the electrodes and electrode-electrolyte interfaces during charging and discharging processes is expected to provide strong insight into the origin of interface resistance and mechanism of cell degradation. Up to date, X-ray and electron spectroscopy techniques have led the field of operando measurement. However, the spatial resolution of those techniques is insufficient to characterize next generation devices that actively utilize nanostructure. Thus, in our group, as an operando measurement technique to evaluate the local properties at nanoscale and even down to the atomic scale, we have been working on developing scanning probe microscopy (SPM) systems that operate under various environments (under light irradiation, voltage application, inert atmospheric conditions). In this talk, we will introduce recent our works related to the characterization of perovskite SCs and all-solid-state LIBs by operando nano-scale profiling of electrical potential distribution using Kelvin probe force microscopy (KPFM). Perovskite solar cells (PSCs) have attracted great research interest owing to their advantages in high power conversion efficiency and low-cost fabrication. Although the power conversion efficiency of PSCs is very high (record is 22.7 %), the detailed photovoltaic conversion processes has not well understood yet compared with the conventional inorganic SCs. In this work, we used KPFM to measure internal electrical potential distribution of PSCs during device operation. We observed that the change of electrical potential induced by illumination occurred strongly at the interface between the perovskite film and charge transport layers, which suggests that charge separation mainly occurred at those interfaces, not in the perovskite film. Also, we found that the position of charge separation varied depending on the composition of perovskite materials and the device structure. These findings will be helpful for understanding the fundamental mechanism within PSCs and achieving high device efficiency. All-solid-state (ASS) LIBs are a promising candidate for next-generation energy storage devices. However, solid electrolytes for the current ASS-LIBs have various disadvantages, such as low power densities caused by high ionic resistivity at the interfaces between active materials and solid electrolytes. The high ionic resistivity has been attributed to the Li depleted layer or defects at the interfacial layer. For the fundamental understanding of the origin of interfacial resistivity, novel in situ techniques for measuring the distribution of the internal potential and/or Li ion concentration of LIB cells are strongly required. In this work, we combined Ar ion milling under non-atmospheric conditions with cross-sectional KPFM for direct imaging of the internal electrical potential distribution of the ASS-LIBs. We succeeded in the direct visualization of the change in the potential distribution of the cathode composite electrode arising from the battery charging (electrochemical reaction). The results obtained provided several insights into the battery operation, such as the behavior of Li ions and inhomogeneity of electrochemical reactions in the electrode.

Localized charge in various configurations of magnetic domain wall in a Weyl semimetal

We numerically investigate the electronic properties of magnetic domain walls formed in a Weyl semimetal. Electric charge distribution is computed from the electron wave functions, by numerically diagonalizing the Hamiltonian under several types of domain walls. We find a certain amount of electric charge localized around the domain wall, depending on the texture of the domain wall. This localized charge stems from the degeneracy of Landau states under the axial magnetic field, which corresponds to the curl in the magnetic texture. The localized charge enables one to drive the domain wall motion by applying an external electric field without injecting an electric current, which is distinct from the ordinary spin-transfer torque and is free from Joule heating.

Enhanced photoactivity of Bi2WO6 by iodide insertion into the interlayer for water purification under visible light

An iodine intercalated Bi2WO6 was fabricated by a facile hydrothermal method (160 °C, 2 h) and characterized by field emission scanning electron microscope, high resolution transmission electron microscopy, nitrogen adsorption/desorption isotherms, X-ray diffraction and X-ray photoelectron spectroscopy, Fourier-transform infrared and UV-Vis diffuse reflectance spectra. The I0.30-Bi2WO6 with an I/W molar ratio of 0.30 was highly effective for the degradation and mineralization of 2-chlorophenol, rhodamine B, bisphenol A, phenol, ciprofloxacin and sulfamethoxazole in water under visible light. Furthermore, the visible-light-driven photocatalytic activity of Bi2WO6 was enhanced 3.1 times by the introduction of I−. The characterized results indicated that I− mainly inserted into the interlayer of Bi2WO6, expanding the layer spacing, favoring the efficient charge separation and transfer and prohibiting the recombination of the photogenerated electrons and holes. Specially, the XPS analysis indicated the I− ions substitued the absorbed oxygen to chemically bond in the layered Bi2WO6, resulting in the change of the electric charge distribution of Bi2WO6. Moreover, the BET surface area was increased from 25.2 m2 g−1 for Bi2WO6 to 66.7 m2 g−1 for I0.30-Bi2WO6 for more surface active sites. In addition, the band gap was narrowed for expanded optical absorption in the visible light region. ESR and radicals trapping experiments verified holes were the main active species for the degradation of organic pollutants. Simultaneously, the more positive potential of valence band in iodine intercalated Bi2WO6 could enhance the oxidative power of the photogenerated holes, resulting in the efficient removal of refractory organic pollutants in water.

Plasmonic nano-tweezer based on square nanoplate tetramers.

The research fields of trapping nanoparticles have experienced a huge development in recent years, which mainly benefits from the unique field enhancement in plasmonic nanomaterials. Since the large field enhancement originates from the excited localized surface plasmon at the metal surface, exploring novel metal nanostructures with high trapping efficiency is always the main goal in this field. In this work, the plasmonic trapping of nanoparticles based on the gold periodic square tetramers (PST) was investigated through full-wave simulations using the finite-difference time-domain (FDTD) method. The electric field and surface charge distributions on the surface of PST indicate that both the trapping position and efficiency are influenced by orientations of the square nanoplates. The maximum electromagnetic enhancement is achieved when all square nanoplates rotate 45° along the z axis. Therefore, the gradient force and trapping potential of this PST with optimal orientation were further studied, and the results indicate that a dielectric nanoparticle of 15nm radius can be stably captured. Furthermore, the calculation results show that the plasmonic trapping with this PST exhibits strong polarization dependence. It is easy to change the trapping position and the field intensity by tuning the polarization of the incident wave. Our work enables a deeper understanding of this kind of plasmonic trapping and could have potential applications in biomedical research and life science.

Electrostatic force microscopy analysis of Bi0.7Dy0.3FeO3 thin films prepared by pulsed laser deposition integrated with ZnO films for microelectromechanical systems and memory applications

In this paper, we report the charge trapping phenomena in zinc oxide (n-ZnO) and Bi0.7Dy0.3FeO3(BDFO)/ZnO thin films deposited onp-type <100> conducting Si substrate. The significant change in contrast above the protrusions of ZnO verifies the possibility of heavy accumulation of injected holes in there. The ZnO and BDFO/ZnO films were characterized by the electrostatic force microscopy (EFM) to understand the phase dependence phenomenon on the bias supporting electron tunnelling. The EFM has an important role in the analysis of electrical transport mechanism characterization and electric charge distribution of local surface in nanoscale devices. It was observed that in BDFO/ZnO, the contrast of EFM images remains constant with the bias switching and that primarily indicates availability of trap sites to host electrons. The change in contrast over the protrusions of ZnO suggests that mobility of the electrical charge carriers may be through the grain boundary. The formation of these hole-trapped sites may be assumed by bond breaking phenomenon.

E-Invariant Quantized Motion of Valence Quarks

In sub-proton space wave processes are impossible. The analog of the Klein–Gordon equation in sub-proton space is elliptical and describes a stationary system with a constant number of particles. For dynamical processes, separation of variables is used and in each quantum of motion of the quark two states are distinguished: a localization state and a translation state with infinite velocity. Alternation of these states describes the motion of a quark. The mathematical expectations of the lifetimes of the localization states and the spatial extents of the translation states for a free quark and for a quark in a centrally symmetric potential are found. The action after one quantum of motion is equal to the Planck constant. The one-sided Laplace transform is used to determine the Green’s function. Use of path integrals shows that the quantized trajectory of a quark is a broken line enveloping the classical trajectory of oscillation of the quark. Comparison of the calculated electric charge distribution in a proton with its experimental value gives satisfactory results. A hypothesis is formulated, according to which the three Grand Geometries of space correspond to the three main interactions of elementary particles.