Field Shielding Research Articles

Method for design of two-level system of active shielding of power frequency magnetic field based on a quasi-static model

Aim. Development of method for design a two-level active shielding system for an industrial frequency magnetic field based on a quasi-static model of a magnetic field generated by power line wires and compensating windings of an active shielding system, including coarse open and precise closed control. Methodology. At the first level rough control of the magnetic field in open-loop form is carried out based on a quasi-static model of a magnetic field generated by power line wires and compensating windings of an active shielding system. This design calculated based on the finite element calculations system COMSOL Multiphysics. At the second level, a stabilizing accurate control of the magnetic field is implemented in the form of a dynamic closed system containing, in addition plant, also power amplifiers and measuring devices of the system. This design calculated based on the calculations system MATLAB. Results. The results of theoretical and experimental studies of optimal two-level active shielding system of magnetic field in residential building from power transmission line with a «Barrel» type arrangement of wires by means of active canceling with single compensating winding are presented. Originality. For the first time, the method for design a two-level active shielding system for an power frequency magnetic field based on a quasi-static model of a magnetic field generated by power line wires and compensating windings of an active shielding system, including coarse open and precise closed control is developed. Practical value. It is shown the possibility to reduce the level of magnetic field induction in residential building from power transmission line with a «Barrel» type arrangement of wires by means of active canceling with single compensating winding with initial induction of 3.5 µT to a safe level for the population adopted in Europe with an induction of 0.5 µT.

Influence of the magnetic field on the nucleation and properties of 0-degree domain walls in uniaxial films with inhomogeneous magnetoelectric interaction

This study investigates the behavior of 0°-domain walls arising in uniaxial magnetic films with a flexomagnetoelectric (FME) effect in a magnetic field. It is shown that at certain magnetic field orientations, it is possible to significantly enhance (or weaken) the degree of manifestation of the FME effect in the studied films. In addition, by varying the magnitude and direction of the magnetic field, it is possible to significantly lower (up to zero) the value of the critical electric field at the origin of this inhomogeneity. It is also established that the 0°-domain wall of the non-Neel type, in which induced bound charges do not create a resultant field (field shielding); when a magnetic field is directed perpendicular to the plane of rotation of magnetic moments, a FME effect occurs, which increases with increasing magnitude of the magnetic field.

A multi-mobility model for polymer insulation: Role of high-mobility space charge on breakdown with high dv/dt voltages

The failure of polymeric solid insulation under transient voltages is closely associated with space charge. In this study, DC and AC field dependent conduction characteristics of epoxy resin were investigated using the space charge limited current and high voltage broadband dielectric spectrum methods. The breakdown voltages (BDVs) were examined over a wide range of DC voltage ramp rates. The results reveal a threshold effect of AC conduction loss below 600 Hz with respect to the electric field. By analyzing charge migration laws, a mobility distribution was deduced, with an upper limit of 10−9m2V−1s−1, which is much higher than the measured DC mobility of 10−14m2V−1s−1. A multi-mobility bipolar charge transport model was proposed by introducing the obtained mobility distribution. Compared to the single-mobility model, high-mobility carriers induce larger unblocked space charge currents for high dv/dt voltages, leading to lower values of BDV, which is consistent with experiment results. As the voltage ramp rate decreases, both simulation and experiment demonstrate higher BDVs due to the field shielding effect of homocharges.

Broadband radar absorbing metamaterial based on Al @SiO2 conductive composite film.

Artificially designed metamaterial structures can manipulate electromagnetic waves, endowing them with exotic physical properties that are not found in natural materials, such as negative refractive index, superlens, and inverse Doppler effect. These characteristics are widely applied in various engineering and military applications. Due to increasingly complex application environments and innovation in radar detection technology, the combination of broadband absorption performance under thin thickness and efficient preparation methods at low cost is often the focus of research on new generation stealth materials. Here, we propose Al@SiO2 composite conductive film metamaterial (Al@SiO2 CCFM) to achieve wideband absorption of electromagnetic waves. This metamaterial structure combines two resonant units, resulting in three absorption bands in the absorption curve. The results show that the absorption rate of the metamaterial is above 90% in the frequency range of 10.6 GHz to 26.0 GHz. The resonance mechanism between multiple structures is a prerequisite for achieving wideband absorption. The materials Al and SiO2 used in Al@SiO2 CCFM are inexpensive and abundant, and the fabrication method is simple. Therefore, they hold great potential for large-scale applications in the multispectral stealth and electromagnetic shielding field.

A controllable interlayer shielding effect in twisted multilayer graphene quantum dots.

When multilayer graphene (MLG) is subjected to a vertical electric field, electrons traverse across the layers and its interlayer electrical conductance and shielding effect exhibit remarkable diversity, leading to exotic phenomena and diverse applications in photoelectric devices. The rearrangement of electrons induced by this external field is aptly described by polarizability, which quantifies the electronic response to the applied field. In this work, we have developed a polarizability decomposition scheme based on field-induced electron density variations computed using a first-principles approach. This scheme allows us to isolate the inter- and intra-layer contributions from the total polarizability of twisted multilayer graphene (TMG) quantum dots. The inter- and intra-layer counterparts reflect the charge transfer (CT) and field shielding effects among the layers, respectively. While the strongest shield effect is observed between the outermost two layers, the largest CT change is noted in the outermost layers, but small or nearly zero CT changes in the inner layers. Significant CT and shielding effects are observed not only in strongly coupled Bernal stacking, but also in the structures misaligned from full-(AA)N stacking by a small and size-dependent twist angle. The dielectric behaviors of the TMG quantum dots of a few layers are layer-dependent and different from those of typical dielectrics. Moreover, both the shielding and CT effects exhibit variation with thickness, twist angle and disc size, suggesting controllable conductive/dielectric conversion in the vertical direction. Considering the inter- and intralayer polarizability, our study addresses the precise modulation of interlayer conductance and shielding effect for TMG quantum dots, essential for microstructure design and performance manipulation of MLG-based photoelectric devices.

(Invited) Advanced Design Concepts for Vertical Gallium Nitride MOSFETs

Wide-bandgap semiconductors have a significant advantage over conventional Si-based electronics by leveraging materials properties to achieve higher breakdown voltage, lower on-resistance, and high-frequency operation. Gallium nitride (GaN) is of interest for vertical device architectures but directly competes with the already established silicon carbide (SiC) power devices. In the case of vertical GaN rectifiers which are unipolar figure-of-merit limited, the materials advantage of GaN provides a modest gain in terms of critical electric field and very slight gains in bulk mobility and saturation velocity, while being at a disadvantage in terms of thermal conductivity compared to SiC. However, despite still being a very immature technology, vertical GaN MOSFETs have demonstrated channel mobilities upwards of 200 cm2/V·s, over three times that of SiC-based MOSFETs. For 1200V-class devices, channel mobility directly contributes to a significant portion of device on-resistance, and it is therefore expected that vertical GaN MOSFETs would offer a substantial performance advantage compared to SiC MOSFETs. Despite this, the development of vertical GaN devices that demonstrate this theoretical potential faces many challenges. Several fundamental limitations exist within the manufacturing process that prohibit GaN devices from directly mirroring the design rules for similar SiC devices. In this talk, we will discuss several key design concepts recently developed for vertical GaN MOSFETs which serve to address several critical issues for GaN.Limitations in selective-area doping for GaN provide an additional challenge in designing edge termination structures, advanced features that protect the gate dielectric during the blocking state, and provides restrictions on minimizing cell pitch. Proper edge termination design is required to reach an avalanche voltage near the theoretical limit and avoid early breakdown. We present an optimized design point for the edge termination with a good match between theoretical and experimental data using a step-etched junction termination extension. Despite a well-designed edge termination, early breakdown will occur in the gate dielectric at the bottom of the gate trench due to field crowding in the dielectric at high blocking voltages. We propose a new method for protecting the gate dielectric by means of a buried field shield formed by an etch-and-regrowth process. Experimental data shows this gate dielectric failure can occur as early as 1/3rd of the designed blocking voltage. The field shield design is shown in simulation to sufficiently reduce the electric field in the gate dielectric to below 4 MV/cm with minimal or no derating of the device depending on geometry of the shield. Additional methods will be presented on new techniques to minimize cell pitch, a critical factor necessary to compete against SiC. Cell pitch minimization not only reduces on-resistance and gate-charge trade-offs, but it is also a driving factor to reduce cost and increase die density on wafer. Finally, techniques have been developed for advanced metal contact designs specific to the trench MOSFET, which further aid in reducing cell pitch. This work was supported by the Electric Drivetrain Consortium managed by Susan Rogers of DOE’s Vehicle Technologies Office. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This paper describes objective technical results and analysis. Any subjective views or opinions that might be expressed in the paper do not necessarily represent the views of the U.S. Department of Energy or the United States Government.

The role of а buffer layer at the contact with silicon in structures with an insulating gap made of a material replacing SiO2

The shape of high-frequency capacitance-voltage characteristics of structures with an insulating layer replacing silicon oxide is considered. It is shown that the buffer layer interaction on the interface with silicon substrates is related to the shielding of external electric fields by charges of the electron traps. It is found that the presence of two plateaus in the high-frequency capacitance-voltage characteristics does not necessarily indicate deep depletion and strong enrichment of a semiconductor. The presence of both capacitive plateaus in the case of strong screening can be explained by the pinning of the Fermi level of Si on electron traps of the buffer layer with a high concentration and a U-shaped spectrum. An algorithm is formulated for calculating the band bending in a semiconductor from the minimal values of the high-frequency capacitance of a sample in the region of depletion effects on the substrate. The theoretical construction was used for determining the characteristics of a structure with an insulating HfO2 layer and it was shown that in this case the buffer layer almost completely shields external electric fields, which prevents significant band bending in the silicon substrate.

Design and Performance Analysis of New Coupling Magnetic Core Structure for Dynamic Wireless Charging System of Electric Vehicle

Aiming at the problems of high cost, low efficiency, low power, and high electromagnetic radiation in the dynamic wireless charging system for electric vehicles (EVs), the cover‐like coupling structure and the return‐like coupling structure are designed, and the unique concave structure has excellent engineering practicability. Using Ansoft software for simulation and analysis, the newly proposed two coupling structures have significantly improved the induced voltage and electromagnetic induction strength at the pickup end compared with other commonly used coupling core structures. According to the advantages of practical applications, the application of its composite core structure for simulation and analysis proves that the cover‐like structure of the magnetic field strength at the pickup end not only enhances the magnetic field strength on the coil but also has a good magnetic field shielding effect. The lateral displacement of the EV is kept within the range of 10 cm, the coupling distance is 0–5 cm, the charging is stable, and the transmission efficiency is high. Finally, a dynamic wireless charging experimental platform for small EVs is constructed, which verifies that the new coupling core structure can significantly improve the transmission power and efficiency of the charging system and significantly reduce the economic cost.

Modeling, analysis, and shielding of the electric field between extra-high-voltage AC transmission lines and oil pipelines

The static charges and induced voltages from extra-high-voltage alternating current transmission lines (EHVACTLs) on parallel oil pipelines (POPLs) raise the risk levels for people and animals. Thus, the objective of this paper was to reduce and/or mitigate the electric field which is concentrated on POPLs by using grounded shield wires under EHVACTLs. Three techniques are employed to reduce the electric field effects on POPLs of two distinct types of transmission lines (TLs), 500 kV and 220 kV. The first technique involves raising the tower’s height to improve the clearance space between the POPLs and the TL conductors. The second technique is increasing the horizontal distance between the POPLs and the nearest stressed conductors of the TL. The third technique involves placing shield wires beneath the stressed conductors of the EHVACTLs. The electric field under the EHVACTLs is calculated with and without the grounded shield wires using charge simulation method. The results of the first technique revealed that with increasing the tower height from 10 m to 15, 20, 25, and 30 m, the electric field decreased by 43.75%, 62.5%, 68.75%, and 75%, respectively. Herein, employing the second technique, the electric field intensity is reduced by 20% and 21% depending on the POPL placed at a distance from the right stressed conductor equal to the horizontal clearance between conductors of 500 kV and 220 kV, respectively. Besides, the results of the third technique proved that the shield wires under the EHVACTLs reduced the electric field intensity on the POPLs by 17.65% and 24.71% for 500-kV and 220-kV TLs, respectively.

EXPERIMENTAL STUDIES OF NOISE POLLUTION OF MECHANICAL PROCESSING PLANTS

Purpose. Determination of noise pollution at the workplace of workers of metal-cutting machines of turning, milling and drilling groups. Methodology. An experimental study of the noise load at the workplace of workers working on lathes, milling and drilling group machines. The research was carried out using a testo 816-1 digital noise level meter, Sound Forge Pro software and a mathematical package for the formation of noise dependences on the type and mode of operation of the machines. Results. An experimental study of the noise load at the workplace of workers working on metal-cutting machines, namely universal lathe-screw-cutting machines (type 1K62 and CA6136), vertical milling machines (type 6P11A and F2-250), vertical milling machine with CNC (type XS5036C) and radial drilling machine (type 2L53U). In addition, it was established that the type of machine affects the level of noise pollution at the workplace of metal-cutting machine workers. For example, the machines used for drilling are characterized by high noise values in all octave frequency ranges and all operating modes, increasing the noise level by 15 dB (16.5%) on average. Milling machines, compared to lathes, show higher noise values at medium and high octave frequencies by 7 dB (8.4%). Based on the results of the study, an adequate polynomial dependence of the fifth order was determined, which describes the noise levels relative to the frequency and corresponds to the results of the natural experiment. The resulting dependencies have practical applications in the development of component materials for simultaneous shielding of both magnetic fields of an electromagnetic field of industrial frequency and electromagnetic fields of different frequencies. Scientific novelty. The solution of this problem can be used in the future to assess the risk of occupational diseases among workers working at mechanical processing stations. Practical significance. The determined dependence will allow further consideration of the issue related to the protection of employees of mechanical processing stations from noise pollution arising during the operation of metal-cutting machines of various groups. Key words: railway, metalworking machine, noise pollution, noise.

Evaluation of photon, proton, and alpha interaction parameters of EDTMPLu and MDPLu medications used for some bone cancer

In this study, we explore the interactions of photons, protons, and alpha with matter in the context of two drugs, MDPLu and EDTMPLu, delving into the interesting field of radiation shielding. Our research is focused on the mass attenuation coefficient (GMAC), effective atomic number (Zeff), buildup factors (EBF and EABF), and dosimetry parameters with the goal of understanding how these factors affect how well these drugs work as radiation shields. Our results show that the effective atomic number was higher in substances with a higher percentage of Z element component, and that the GMAC values for MDPLu medications were the highest, while the GMAC values for EDTMPLu medications were the lowest. Additionally, MDPLu showed the lowest exposure buildup factor (EBF) and energy absorption buildup factor (EABF), further validating its efficacy as a shielding material. Moreover, MDPLu displayed a higher mass-stopping power (MSP) for proton interactions in the lower energy range, making it a prime candidate for specific radiation shielding applications. These insights contribute to our understanding of the radiation-shielding efficacy of bone cancer treatment medications.

Hollow Superstructure In Situ Assembled by Single-Layer Janus Nanospheres toward Electromagnetic Shielding Flame-Retardant Polyurea Composites.

A dodecahedral superstructure consisting of a single layer of Janus spheres containing ZIF-67 nanodots is prepared by in situ polymerization, with ZIF-67 and bio-based phytic acid (PA) as templates and dopants. It is used to improve the flame retardant, electromagnetic (EMI) shielding, and thermal conductivity properties of polyurea (PUA). By adding 5wt% polyaniline@cobalt phytate-2.0 (PANI@Co-PA-2.0), the peak of heat release rate and the peak of smoke production rate are reduced by 54.9 and 59.9%, respectively. The peak of CO and CO2 production also decreased by 46.2 and 53.1%, respectively. A decrease in the absorption intensity of aliphatic and aromatic volatiles is also observed. The fire safety of PUA is greatly improved. In addition, PUA/PANI@Co-PA-2.0 exhibits an EMI shielding capability of 22.4dB with the help of reduced graphene oxide, which confirms the possibility of PUA material application in the field of electromagnetic shielding. The 5wt% filler increases the tensile strength of the PUA matrix to 6.3MPa, and the composite material obtains good thermal conductivity. This work provides a viable method for the preparation of a flame-retardant, conductive, and electromagnetic refractory PUA substrate.

Ti3C2Tx MXene/delignified wood supported flame-retardant phase-change composites with superior solar-thermal conversion efficiency and highly electromagnetic interference shielding for efficient thermal management

The development of form-stable phase-change material (PCM) with solar-thermal harvest, electromagnetic interference (EMI) shielding, and flame-retardancy is crucial for efficient building energy management and conservation. Herein, novel Ti3C2Tx MXene/delignified wood supported form-stable phase-change composites (PMPCMs) with superior solar-thermal conversion efficiency, highly EMI shielding effects, and excellent flame-retardancy were fabricated by alkaline boiling delignification, ammonium dihydrogen phosphate (ADP) and MXene deposition, and melted n-octadecane impregnation. Benefiting from the powerful surface tension and capillary force of the wood-based support materials, PMPCMs can effectively encapsulate the melted n-alkane molecules and inhibit their leakage. The differential scanning calorimetry results showed that PMPCMs possessed superior n-octadecane encapsulation yield and high thermal energy storage density (166.9–191.6 J/g). Decorating delignified wood by MXene significantly improved the solar-thermal storage efficiency (up to 88.4 %) and EMI shielding performance of PMPCMs. The average EMI shielding effectiveness of PMPCM-10 was enhanced to 34.12 dB in X-band frequency range of 8.2–12.4 GHz. Moreover, with the introduction of the flame-retardant ADP, the peak heat release rate (pHRR) and total heat release (THR) of PMPCMs decreased noticeably, demonstrating the enhanced flame retardancy of delignified wood supported phase-change composites. In summary, PMPCMs exhibited superior application prospects in building energy management and electromagnetic shielding fields.

Electromagnetic Shielding of Two-Circuit Overhead Power Lines Magnetic Field

The purpose of the work is to design an electromagnetic shield to reduce the level of the magnetic field generated by double-circuit overhead power lines to increase the shielding efficiency of the initial magnetic field in residential buildings to the level of sanitary standards and reduce the sys-tem's sensitivity to changes in system parameters. To achieve this goal, the structure of the electro-magnetic shield is determined, which consists of a single-circuit active and multi-circuit passive parts and is characterized by an increased efficiency of reducing the magnetic field of industrial frequency. The design of an electromagnetic shield is reduced to solving a minimax vector optimization problem, in which the vector objective function is calculated based on solutions of Maxwell's equations in a quasi-stationary approximation using the COMSOL Multiphysics software package. The solution of the minimax vector optimization problem is calculated on the basis of optimization algorithms by a multiswarm of particles from Pareto-optimal solutions. The most important results are theoretical and experimental studies of the effectiveness of the designed electromagnetic shield of the magnetic field generated by double-circuit overhead power lines. The significance of the results obtained lies in the fact that practical recommendations are given on the reasonable choice of the spatial arrangement of the contours of the multi-circuit passive screen and the shielding winding of the robust system of elec-tromagnetic shielding of the magnetic field generated by double-circuit overhead power lines. The possibility of reducing the induction of the initial magnetic field to the level of sanitary standards has been shown as well.

Mechanism and Influence of Dispersants on the Action of Polymer Flocculants Used in Slurry Separation.

The application of polymer flocculants plays a pivotal role in the slurry separation process of shields, and the dispersant used for treating cutter mud cakes can significantly impact the effectiveness of polymer flocculants, potentially leading to reduced efficiency in slurry separation. Experiments were conducted to select appropriate flocculants and investigate the influence of dispersants on flocculant effectiveness, aiming to assess the effect of flocculants and explore the relationships and mechanisms governing their influence. Changes in the patterns of slurry flocculation were revealed in terms of flocculation-driven precipitation and vacuum-filtration effects. The purpose of this article is to provide a reference for the field application of polymer flocculants in the shield field. The conclusions are as follows. Inorganic flocculants containing 0.5% polyaluminum chloride (PAC) exhibit the most effective flocculation, demonstrating strong charge neutralization action. Organic flocculants containing 0.1% cationic polyacrylamides (CPAM) exhibit the most effective flocculation, demonstrating strong bridging and net capture effects. The dispersant sodium hexametaphosphate (SHMP) can significantly weaken the charge-neutralizing action of flocculants and slightly enhance bridging and net capture effects. SHMP can impede the flocculation of slurry with PAC. For CPAM, SHMP can enhance the flocculation of slurry at a low mass fraction (0.1% and 0.3%), while SHMP can significantly hinder flocculation at a high mass fraction (0.5% and 1%). A low mass fraction of SHMP reduced slurry viscosity to 246.3 mPa.s and enhanced vacuum filtration, while a high mass fraction of SHMP increased slurry viscosity to 667.2 mPa.s and hindered vacuum filtration. In conclusion, while dispersants reduce the effectiveness of inorganic flocculants at any mass fraction, a small number of dispersants enhances the performance of organic flocculants; thus, the organic flocculant CPAM is recommended for slurry separation.

Analysis and suppression of magnetic noise of cylindrical nanocrystalline shield in atomic sensors

Magnetic field interference poses a major challenge to the proper functioning of electronic equipment, electronic instruments and ultra-sensitive sensors, so magnetic field shield is a vital component. Particularly for ultra-sensitive atomic sensors, there is a pressing need for magnetic shields with superior performance and reduced magnetic noise. This paper introduces the application of nanocrystalline alloy magnetic shields in ultra-sensitive atomic sensors. We have analyzed the calculation of the longitudinal and transverse magnetic noise of nanocrystalline magnetic shields using a loss separation based approach and establish a magnetic noise model for nanocrystalline alloy magnetic shields. Meanwhile, we investigate the impact of structural parameters on longitudinal and transverse magnetic noise to effectively minimize magnetic noise in the shield. Additionally, we present an error model for magnetic noise, providing valuable theoretical support for mitigating magnetic noise errors in K-Rb-21Ne SERF co-magnetometers. This study contributes to the advancement of magnetic shield technology for ultra-sensitive atomic sensors, improving their overall performance and accuracy.

(Invited) Benchmarking of Beyond the State-of-the-Art Vertical GaN Devices

In this paper theoretical benchmarking of semi-vertical and vertical gallium nitride (GaN) MOSFETs with rated voltage of 1.2 kV to 3.3 kV is performed against silicon carbide (SiC) devices. Limitations of the semi-vertical and vertical state-of-the-art GaN structures have been investigated by simulations. Specific design features and technology requirements for realization of high voltage vertical GaN MOSFETs are discussed and implemented in simulated structures. The main modifications to the structures are reduced cell pitch and introduction of electric field shielding implantation and thick oxide at the gate trench bottom and p-type implanted junction termination. The main findings are: (a) specific on-resistance of vertical GaN devices is 75% and 40% of that for 1.2 kV and 3.3 kV SiC MOSFETs, respectively, (b) semi-vertical GaN show no advantage over SiC MOSFETs for medium and high voltage devices over 1 kV, (c) vertical GaN has potential advantage for high and ultra-high voltage devices.

Shielding and dosimetry parameters for aluminum carbon steel

Aluminum is lightweight durable, versatile, non-toxic, and corrosion-resistant surface, which makes aluminum a perfect material for improving the corrosion properties of aluminum-carbon steel which is important in the radiation domain. In this study, six carbon steel alloys doped with different aluminum concentrations were studied and compared with the standard austenite stainless steel AISI316L. Different parameters for shielding and dosimetry such as mass attenuation coefficient, tenth value layer, mean free path, equivalent effective atomic and electronic numbers were calculated using WinXCom, while the exposure absorption buildup factors, thermal and fast neutron removal cross-sections were calculated using MCNPX and the effective conductivity was calculated using Phy-X/PSD program. Regarding the radiation shielding performance, the addition of aluminum to the carbon alloys has a significant influence on the shielding parameters. The results suggest that the addition of aluminum to the carbon steel alloys would improve its shielding properties so that it is a good result to be used in the field of dosimetry and radiation shielding.

A novel 4H‐SiC accumulation mode MOSFET with ultra‐low specific on‐resistance and improved reverse recovery capability

AbstractA novel 1440‐V 4H‐SiC accumulation mode MOSFET (ACCUFET) with ultra‐low specific on‐resistance and improved reverse recovery performance is proposed in this article. As for the proposed SiC ACCUFET, the channel region can be completely depleted by the P‐type heavily doped polysilicon gate to build an electron barrier and realize a normally‐off device. And a Schottky barrier diode (SBD) is integrated below the trench gates on both sides, which brings the feasibility of realizing reverse conduction function of the proposed ACCUFET. Also, the p‐shield regions under the Schottky contact metal provide a good electric field shielding effect for the gate oxide. Compared with the conventional SiC trench MOSFET, the numerical simulation results show that the specific on‐resistance (Ron,sp) of the proposed ACCUFET is reduced by more than 64%. The high‐frequency figures‐of‐merit HFOM [Ron,sp × Cgd] and HFOM [Ron,sp × Qgd] of the proposed device are improved by 53.19% and 58.74%, respectively. The reverse recovery time (trr), and reverse recovery charge (Qrr) are reduced by 23.28% and 82.73%, respectively. In addition, the results also indicate that the proposed device has a better latch‐up immunity compared with the conventional SiC trench MOSFET. The excellent device performance and the simple manufacturing process provide a good prospect for the application of the proposed device.

Uncovering the attributes of Bi2O3-CdO-TeO2 glasses: examining their structural, optical, and gamma ray shielding properties

The present work deals with the fabrication of Bi2O3-CdO-TeO2 glasses using the melt quenching technique. XRD determines the amorphous nature, while the FTIR technique provides information about the molecular vibrations present in a sample. To understand the optical properties of the glass, UV–Vis absorption spectra in the 200–800 nm range and Tauc’s plot method to determine the indirect allowed band gap energies are used. The band gap energy decreases as the concentration of Bi2O3 is increasing. Additionally, Monte Carlo (MC) simulation technique has been used to assess the linear attenuation coefficient (μ). The evaluation demonstrates an improvement in μ by 12% and 7%, respectively at 0.15 MeV and 0.662 MeV with increasing the Bi2O3 concentration from 45 mol% to 60 mol%. The half-value thickness (Δ0.5) and lead equivalent thickness (Δeq) of the fabricated samples marginally improved by the minor increase in μ in the mid-gamma energy region. The fabricated samples have applications in the field of gamma-ray shielding.