Modeling Of Electric Field Distribution Research Articles

Optimization algorithm of 500kVGIS circuit breaker electric field simulation based on GPU acceleration

It proposes an optimization approach for electric field simulation in 500kV gas-insulated switchgear (GIS) circuit breakers that use GPU acceleration. Accurate modelling of electric field distribution within GIS circuit breakers is critical for assuring the dependability and safety of high voltage power systems. However, the computational complexity of simulating these systems presents substantial obstacles to established approaches. The goal of this work is to improve the speed, efficiency, and scalability of electric field simulations by leveraging GPU parallel processing capabilities. They methodically build and refine the simulation algorithm, utilizing techniques such as parallel algorithm design, GPU architecture optimization, and efficient memory management. Through rigorous performance studies, they demonstrate significant increases in computational efficiency relative to CPU-based techniques, with an average speed up of 15x. Furthermore, the scalability of the GPU-accelerated method is evaluated, demonstrating near-linear scalability up to 8 GPUs. Validation against experimental observations and analytical models indicates that the simulation findings are accurate and robust. This study helps the progress of electric field simulation tools for GIS circuit breakers by providing insights into electric field behaviour and aiding design optimization and performance evaluation in high voltage power systems.

Evaluation of dynamics of charge accumulation and dissipation processes in Ge15Se85 thin film under electron beam irradiation by mapping surface potential distribution

The interaction of Ge15Se85 amorphous chalcogenide films with an electron beam has been studied. Three ranges of electron irradiation doses, in which a surface relief of various shapes is formed, are found. The presence and persistence of the surface potential for a long time after film irradiation have been established using the Kelvin probe force microscopy (KPFM). It is shown that the formation of surface relief is result of the charge accumulation in the interaction region. Based on the mapping of surface potential distribution in irradiated regions using KPFM we propose models of electric field distribution in the irradiated spots and suggest mechanism of electron-induced mass transfer. It has been suggested that the formation of a high surface relief structures is due to the electron-induced plastic effect. It is shown that the appearance of asymptotically sharp Taylor cones in chalcogenide films is due to charge collapse in the interaction region when the volume charge density and internal electric field strength exceed their critical values.

Increasing Brain Gamma Activity Improves Episodic Memory and Restores Cholinergic Dysfunction in Alzheimer's Disease.

ObjectiveThis study aimed to assess whether non‐invasive brain stimulation with transcranial alternating current stimulation at gamma‐frequency (γ‐tACS) applied over the precuneus can improve episodic memory and modulate cholinergic transmission by modulating cerebral rhythms in early Alzheimer's disease (AD).MethodsIn this randomized, double‐blind, sham controlled, crossover study, 60 AD patients underwent a clinical and neurophysiological evaluation including assessment of episodic memory and cholinergic transmission pre and post 60 minutes treatment with γ‐tACS targeting the precuneus or sham tACS. In a subset of 10 patients, EEG analysis and individualized modelling of electric field distribution were carried out. Predictors to γ‐tACS efficacy were evaluated.ResultsWe observed a significant improvement in the Rey Auditory Verbal Learning (RAVL) test immediate recall (p < 0.001) and delayed recall scores (p < 0.001) after γ‐tACS but not after sham tACS. Face‐name associations scores improved with γ‐tACS (p < 0.001) but not after sham tACS. Short latency afferent inhibition, an indirect measure of cholinergic transmission, increased only after γ‐tACS (p < 0.001). ApoE genotype and baseline cognitive impairment were the best predictors of response to γ‐tACS. Clinical improvement correlated with the increase in gamma frequencies in posterior regions and with the amount of predicted electric field distribution in the precuneus.InterpretationPrecuneus γ‐tACS, able to increase γ‐power activity on the posterior brain regions, showed a significant improvement of episodic memory performances, along with restoration of intracortical excitability measures of cholinergic transmission. Response to γ‐tACS was dependent on genetic factors and disease stage. ANN NEUROL 2022;92:322–334

Investigation of the anti-corrosion performance of a Cu/Ni–B4C superhydrophobic coating with self-cleaning and abrasion resistance properties

A Cu/Ni–B4C superhydrophobic coating was fabricated on the surface of Q235 steel under different current density via electrodeposition. The distribution of electric field influenced by current density controls the growth of rough structure. Therefore, the effect of current density was measured by the morphology and wettability of coating and analyzed by Electric field distribution model. The coating surface demonstrates the most uniform and compact rough structure at a current density of 3 A/dm2 (MC-3) obtaining contact angle 160 ± 2° after the surface energy reduced by stearic acid. The self-cleaning performance and mechanical stability of MC-3 coating were studied. The potentiodynamic polarization curve (PPC) and electrochemical impedance spectroscopy (EIS) were used to measure the anti-corrosion and protection performance of the coatings with different morphology and contact angle. The protective performance of MC-3 coating soaked in 3.5 wt% NaCl solution for different time was studied by EIS. The wetting stability of different coatings was studied by single frequency impedance spectroscopy. Then the double protective mechanism of superhydrophobic coating was described and the corresponding model was established.

An Automated Workflow for the Electric Field Modeling of High-definition Transcranial Direct Current Stimulation (HD-tDCS) in Chronic Stroke with Lesions.

Transcranial Direct Current Stimulation is a popular noninvasive brain stimulation (NIBS) technique that modulates brain excitability by means of low-amplitude electrical current (usually <4mA) delivered to the electrodes on the scalp. The NIBS research has gained significant momentum in the past decade, prompting tDCS as an adjunctive therapeutic tool for neuromuscular disorders like stroke. However, due to stroke lesions and the differences in individual neuroanatomy, the targeted brain region may not show the same response upon NIBS across stroke patients. To this end, we conducted a study to test the feasibility of targeted NIBS. The hand motor hotspot (HMH) for each chronic stroke participant was identified using Neuronavigated Transcranial Magnetic Stimulation (TMS). After identifying the HMH as the neural target site, we applied High-definition TDCS with the current delivered at 2mA for 20 minutes. To simulate the effects of HD-tDCS in the brain, especially with stroke lesions, we used the computational modeling tool (ROAST). The lesion mask was identified using an automated tool (LINDA). This paper demonstrates that the stroke lesions can be incorporated in the computational modeling of electric field distribution upon HD-tDCS without manual intervention.

Monopolar gene electrotransfer enhances plasmid DNA delivery to skin

A novel monopolar electroporation system and methodologies were developed for in vivo electroporation intended for potential clinical applications such as gene therapy. We hypothesized that an asymmetric anode/cathode electrode applicator geometry could produce favorable electric fields for electroporation, without the typical drawback associated with traditional needle and parallel plate geometries. Three monopolar electrode applicator prototypes were built and tested for gene delivery of reporter genes to the skin in a guinea pig model. Gene expression was evaluated in terms of kinetics over time and expression distribution within the treatment site. Different pulsing parameters, including pulse amplitude, pulse duration, and pulse number were evaluated. Monopolar gene electrotransfer significantly enhanced gene expression compared to controls over the course of 21 days. Gene expression distribution was observed throughout the full thickness of the epidermis, as well as notable expression in the deeper layers of the skin, including the dermis, and the underlying striated muscle without any damage at the treatment site, which is a substantial improvement over previously reported expression confined to the epidermis only. Expression distribution observed is consistent with the electric field distribution model, indicating that our novel electrode geometry results in targeted electroporation and gene transfer. This is important, as it may facilitate translation of many electroporation-based clinical therapies including gene therapies, IRE, and ECT.

Quantum Analytical Model for Lateral Dual Gate UTBB SOI MOSFET for Analog/RF Performance

This paper presents a quantum analytical modeling of UTBB SOIMOSFET as lateral dual gate for the first time. In this paper, a 2-dimensional analytical modeling of electric field distribution, threshold voltage (Vth), surface potential and drain current (ID) have been developed and then including Quantum mechanical effects (QMEs)in it. The proposed model provides an expression for Vth shift due to QMEs, which can be used for compact modeling as a quantum correction term. The results of quantum analytical modeling have been verified with the results achieved from numerical TCAD device simulator. Different analog/ radio frequency (RF) performance parameters like transconductance (gm), output resistance (RO), transconductance generation factor (TGF), intrinsic gain (gm*RO), cut-off frequency (fT), gain bandwidth product (GBW), maximum frequency of oscillation (fmax) etc. has been investigated. The effect of negative voltage on the control gate on RF/analog performance parameters has been studied. Result reveals that the potential of UTTB SOI MOSFET with lateral dual gate becomes a choice for analog and mixed signal SOC applications.

Transient Simulation Model for Electric Field Distribution in Cable Joint

The analysis of the impact of the switching impulse voltage on the internal electric field of the cable joint plays a key role in studying the breakdown of the joint. In this paper, the finite element method is used to simulate the transient electric field of the axisymmetric model of the cable joint. By changing the closing moment, the influence of different closing moments on the electric field intensity distribution is studied and analyzed. The results show that under the switching voltage excitation, when the closing moment at t 0=nT, the electric field distribution in the cable joint is consistent with the steady state without distortion. Others, the point near the root of the stress cone will distort when the switch is closed, the closing moment is at 7.5ms, which is the most serious. The closing time is at 10ms, has the greatest influence on the electric field intensity distribution in the cable joint, especially the stress cone end, the bottom of the high voltage shield and the position near the high voltage conductor in the air domain.

Filtration efficiency investigation of mesh fabrics by polytetrafluoroethylene filament with surface static electricity

Particulate matter (PM) pollution has become a severe environmental problem. The application of some static electric materials with high filtration efficiency became more and more popular. However, the escape of surface voltage was unbeneficial to the long-term application of this material. Herein, this research reported novel static electric materials polytetrafluoroethylene (PTFE) and tourmaline. With the application of these two materials, a kind of fabric with high surface electricity, filtration efficiency, long-term stability and low pressure drop was exploited. This fabric was woven by PTFE filaments containing tourmaline particles of four different content and particle size. By means of the surface electricity and filtration efficiency measurement, the fabric containing 7 wt % tourmaline particles possessed the largest surface electricity of 830 V, as well as highest filtration efficiency of 75.6%. In addition, a model of electric field distribution in filament and fabrics were both proposed by the static electricity test to interpret the mechanism of filtration. The successful fabrication of such an intriguing material might provide a new application for the electret materials for PM removing.

Electrostatic and mechanical properties of extrusion spun PTFE monofilament with integration of microtourmaline particles

ABSTRACTThis study reports on polytetrafluoroethylene (PTFE) monofilaments prepared by extrusion spinning with the integration of tourmaline particles. The resultant PTFE monofilaments have excellent electrostatic properties and contain different amounts and sizes of tourmaline particles. Tensile tests show that the PTFE monofilaments with 7 wt % and 1 wt % of 5 μm particles possessed tensile strengths of 1175 N and 1026 N, which were 12.5% and 23.6% lower than those of the pure PTFE monofilament, respectively. In electrostatic properties, there was 14.3% growth in surface voltage compared with the original PTFE monofilament in the series of monofilaments with varying content of tourmaline particles. When the particle size was 5 μm, the voltage was 14.7% higher than that of pure PTFE monofilament in the series of monofilaments with varying sizes of tourmaline particles. In addition, a model of electric field distribution around the monofilament was proposed based on a static electricity test. Successful research on such an intriguing monofilament might provide a novel application of the PTFE and tourmaline. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46401.

A Model of Electric Field Distribution in Gate Oxide and JFET-Region of 4H-SiC DMOSFETs

For the first time, a full analytical model of the electric field in the gate oxide of 4H-polytype silicon carbide (4H-SiC) power double-implanted MOSFET devices is shown. It takes into account all the relevant physical and geometrical parameters of the device and avoids the use of any fitting parameters. To validate the results of the full-analytical model, comparisons with numerical simulations are reported for device structures having different values of the drift doping concentration and drift thickness as well as of the junction FET (JFET)-region width. Moreover, because the model equations are in closed form, they can be used to derive an adequate JFET-region geometry by fixing the maximum electric field in the oxide and the maximum blocking voltage for a given drift region.

Thermal analysis of induced damage to the healthy cell during RFA of breast tumor

Effective pre-clinical computational modeling strategies have been demonstrated in this article to enable risk free clinical application of radiofrequency ablation (RFA) of breast tumor. The present study (a) determines various optimal regulating parameters required for RFA of tumor and (b) introduces an essential clinical monitoring scheme to minimize the extent of damage to the healthy cell during RFA of tumor. The therapeutic capabilities offered by RFA of breast tumor, viz., the rise in local temperature and induced thermal damage have been predicted by integrating the bioheat transfer model, the electric field distribution model and the thermal damage model. The mathematical model has been validated with the experimental results available in the literature. The results revealed that, the effective damage of tumor volume sparing healthy tissue essentially depends on the voltage, the exposure time, the local heat distribution, the tumor stage and the electrode geometric configuration. It has been confirmed that, the assessment of damage front can accurately determine the extent of damage as compared to the thermal front. The study further evaluates the damaged healthy and tumor volumes due to RFA of different stages of breast cancer. The assessment of cell survival and damage fractions discloses the propensity of reappearance/healing of tumor cells after treatment.

Analytical Modeling of Electric Field Distribution in Dual Material Junctionless Surrounding Gate MOSFETs

Analytical Modeling of Electric Field Distribution in Dual Material Junctionless Surrounding Gate MOSFETs

Electric crosstalk impairs spatial resolution of multi-electrode arrays in retinal implants**This paper was originally submitted for the special issue containing contributions from the Sixth Biennial Research Congress of The Eye and the Chip.

Active multi-electrode arrays are used in vision prostheses, including optic nerve cuffs and cortical and retinal implants for stimulation of neural tissue. For retinal implants, arrays with up to 1500 electrodes are used in clinical trials. The ability to convey information with high spatial resolution is critical for these applications. To assess the extent to which spatial resolution is impaired by electric crosstalk, finite-element simulation of electric field distribution in a simplified passive tissue model of the retina is performed. The effects of electrode size, electrode spacing, distance to target cells, and electrode return configuration (monopolar, tripolar, hexagonal) on spatial resolution is investigated in the form of a mathematical model of electric field distribution. Results show that spatial resolution is impaired with increased distance from the electrode array to the target cells. This effect can be partly compensated by non-monopolar electrode configurations and larger electrode diameters, albeit at the expense of lower pixel densities due to larger covering areas by each stimulation electrode. In applications where multi-electrode arrays can be brought into close proximity to target cells, as presumably with epiretinal implants, smaller electrodes in monopolar configuration can provide the highest spatial resolution. However, if the implantation site is further from the target cells, as is the case in suprachoroidal approaches, hexagonally guarded electrode return configurations can convey higher spatial resolution.

Model for Electrical Field Distribution in the Human Esophagus during Stimulation with Patch and Ring Electrodes

Introduction. Electrical stimulation is used in experimental human pain models. The aim was to develop a model that visualizes the distribution of electrical field in the esophagus close to ring and patch electrodes mounted on an esophageal catheter and to explain the obtained sensory responses. Methods. Electrical field distribution in esophageal layers (mucosa, muscle layers, and surrounding tissue) was computed using a finite element model based on a 3D model. Each layer was assigned different electrical properties. An electrical field exceeding 20 V/m was considered to activate the esophageal afferents. Results. The model output showed homogeneous and symmetrical field surrounding ring electrodes compared to a saddle-shaped field around patch electrodes. Increasing interelectrode distance enlarged the electrical field in muscle layer. Conclusion. Ring electrodes with 10 mm interelectrode distance seem optimal for future catheter designs. Though the model needs further validation, the results seem useful for electrode designs and understanding of electrical stimulation patterns.

Mathematical Model of Electric Field Distribution at a Critical State in Bubble Electrospinning

Bubble electrospinning is a novel method to produce ultrafine nanofibers. In this work, a mathematical model of the electric field distribution in a critical state was established for bubble electrospinning process and was numerically simulated using finite element method. The results indicated that the maximum electric force occurred at the tip of the bubble, it is probably for this reason that the first jet occurs at the tip of the bubble, when the electrical force exceeds the surface tension, which also possibly induces bubble bursting.

2D Transconductance to Drain Current Ratio Modeling of Dual Material Surrounding Gate Nanoscale SOl MOSFETs

The prominent advantages of Dual Material Surrounding Gate (DMSG) MOSFETs are higher speed, higher current drive, lower power consumption, enhanced short channel immunity and increased packing density, thus promising new opportunities for scaling and advanced design. In this Paper, we present Transconductance-to-drain current ratio and electric field distribution model for dual material surrounding gate (DMSGTs) MOSFETs. Transconductance-to-drain current ratio is a better criterion to access the performance of a device than the transconductance. This proposed model offers the basic designing guidance for dual material surrounding gate MOSFETs.

Nucleic Acids Electrotransfer-Based Gene Therapy (Electrogenetherapy): Past, Current, and Future

About 25 years after the publication of the first report on gene transfer in vitro in cultured cells by the means of electric pulses delivery, reversible cell electroporation for gene transfer and gene therapy (DNA electrotransfer) is at a cross in its development. Present knowledge on the effects of cell exposure to appropriate electric field pulses, particularly at the level of the cell membrane, is reported here. The importance of the models of electric field distribution in tissues and of the correct choice of electrodes and applied voltages is highlighted. The mechanisms involved in DNA electrotransfer, which include cell electropermeabilization and DNA electrophoresis, are also surveyed. This knowledge has allowed developing new nucleic acids electrotransfer conditions using combinations of permeabilizing pulses of high voltage and short duration, and of electrophoretic pulses of low voltage and long duration, which are very efficient and safer. Feasibility of electric pulses delivery for gene transfer in humans is discussed taking into account that electric pulses delivery is already regularly used for localized drug delivery in the treatment of cutaneous and subcutaneous solid tumors by electrochemotherapy. Because recent technological developments made DNA electrotransfer more and more efficient and safer, this non-viral gene therapy approach is now ready to reach the clinical stage. A good understanding of DNA electrotransfer principles and the respect of safe procedures will be key elements for a successful future transfer DNA electrotransfer into the clinics.

Modeling Electric Field Distribution on Insulator under Electron Bombardment in Vacuum

Charging and discharging phenomenon on the surface of materials can be found in plasma display panel, spacecraft charging, high voltage insulator, etc. This report gives a simple explanation on this phenomenon. A scanning electron microscope was used not only as a tool to produce energetic electron beam to charge an insulator without metallic coating and to produce a surface discharging (surface breakdown/flashover) but also to observe the visible charging and discharging on the sample surface. A model of electric field distribution on the surface was developed in order to explain charging and discharging phenomena. Since charging and discharging process involves incubation time, therefore this process can be used to evaluate the insulation property of materials under electron bombardment.

Space charge sign inversion and electric field reconstruction in 24 GeV/ c proton-irradiated MC z Si p +-n(TD)-n + detectors processed via thermal donor introduction

The aim of this study is the evaluation of radiation effects in detectors based on p-type magnetic czochralski (MC z) Si that was converted to n-type by thermal donor (TD) introduction. As-processed p +-p-n + detectors were annealed at 430 °C resulting in p +-n(TD)-n + structures. The space charge sign and the electric field distribution E( x) in MCz Si p +-n(TD)-n + detectors irradiated by 24 GeV/ c protons were analyzed using the data on the current pulse response and the Double Peak (DP) electric field distribution model for heavily irradiated detectors. The approach considers an irradiated detector as a structure with three regions in which the electric field depends on the coordinate, and the induced current pulse response arises from the drift process of free carriers in the detector with variable electric field. Reconstruction of the E( x) profile from the pulse response shapes is performed employing a new method for DP electric field reconstruction. This method includes: (a) a direct extraction of charge loss due to trapping and (b) the fitting of a simulated pulse response to the “corrected” pulse by adjusting the electric field profiles in the three regions. Reconstruction of E( x) distribution showed that in the diodes irradiated by a proton fluence of (2–4)×10 14 p/cm 2 space charge sign inversion has occurred. This is the evidence that the influence of 24 GeV/ c proton radiation on MCz Si p +-n(TD)-n + detectors is similar to that on p +-n-n + detectors based on FZ or diffusion oxygenated n-type Si.