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We exhaustively investigate the temporal correlations between the ultrahigh-frequency (of the order of 1–6 GHz), very high-frequency (of the order of 10–100 MHz), and x-ray (photons with energies from 5 keV to 1 MeV) emissions together with the optical emissions in the near-infrared (within 700–1100 nm) and near-ultraviolet (within 300–400 nm) wavelength regions. The emissions are produced by a laboratory atmospheric discharge developing in an 55 cm air gap at voltages up to 1 MV. When registering various electromagnetic emissions, the discharge current and voltage are measured, as well as nanosecond imaging of the discharge evolution in its own glow is performed. The spatiotemporal localization of the discharge regions associated with the x-ray generation is carried out by employing the group of fast scintillation detectors, and the evolution of plasma structures during the x-ray generation is traced. A chronological map is constructed providing an in-depth understanding of the temporal character and correlations of various electromagnetic emissions. The map allows one to analyze fast ionization processes occurring in the gas-discharge medium and triggering the generation of the corresponding emissions. The generation mechanisms of the considered emissions in an extended high-voltage discharge are discussed. The findings can be helpful in revealing the sources of various electromagnetic emissions accompanying the formation of laboratory and atmospheric discharges. [ABSTRACT FROM AUTHOR]

Ferroelectric thin-film transistors (Fe-TFTs) have promising potential for flexible electronics, memory, and neuromorphic computing applications. Here, we report on a physics-based efficient device model for Fe-TFTs that effectively describes memory switching and device I–V characteristics. This model combines a stochastic multi-domain description of FE switching dynamics with a virtual source treatment of TFT device characteristics. It demonstrates that the memory window of Fe-TFTs depends on the amplitude and duration of the applied voltage pulses, thus suggesting quantitative means of programming and control. Additionally, we introduce a machine-learning-enabled method to automatically generate optimal voltage pulses for accurately programming multiple intermediate FE states, which is crucial for multi-bit memory and neuromorphic computing applications. To showcase the model's applications, we simulate a 4 × 4 crossbar array circuit based on Fe-TFTs, highlighting its utility in performing multiply-accumulate computing operations. This small array can achieve a high speed of ∼ 1.28 tera operations per second (OPS) and a power efficiency of ∼ 0.43 W/PetaOPS. The model developed here is valuable for exploring the capabilities of Fe-TFTs in future flexible memory and computing technologies. [ABSTRACT FROM AUTHOR]

Results of experimental research and two-dimensional hydrodynamical simulations of close to critically damped microsecond timescale underwater electrical explosions of butterfly-shaped foils for six different materials are presented. Using current and voltage waveforms along with multi-frame shadow images of the shocks generated in water, the values of the specific action integral, h, were determined. It is shown that values of h can be calculated based on the average current density and that its value (within error bars) does not change in the range of current densities (0.5–1) × 108 A/cm2. The values of h were found to be consistent with those obtained for sub-microsecond underwater electrical explosions of wires made of the same material but differ from those obtained in earlier research with explosion of wires in vacuum. [ABSTRACT FROM AUTHOR]

To mimic the intricate and adaptive functionalities of biological ion channels, electrohydrodynamic ion transport has been studied extensively, albeit mostly, across uniformly charged nanochannels. Here, we analyze the ion transport under coupled electric field and pressure across heterogeneously charged nanopores with oppositely charged sections on their lateral surface. We only consider such pores with symmetric hourglass-like and cylindrical shapes to focus on the effects of the non-uniform surface charge distribution. Finite-element simulations of a continuum model demonstrate that a pressure applied in either direction of the pore-axis equally suppresses or amplifies the ionic conductance, depending on the electric field polarity, by distorting the quasi-static distribution of ions in the pore. The resulting anomalous mechanical deactivation and activation of ionic current under opposite voltage biases exhibit the functional modularity of our setup, while their intensities are highly tunable, substantially greater than those of analogous behaviors in other nanochannels, and fundamentally correlated to ionic current rectification (ICR) in our pores. A detailed study of ICR subsequently reveals its counterintuitive non-monotonous variations, in the pores, with the magnitude of applied voltage and the pore length, that can help optimize their diode-like behavior. We further illustrate that while the hourglass-shaped nanopores yield the more efficient mechanical suppressors of ion transport, their cylindrical analogs are the superior rectifiers and mechanical amplifiers of ion conduction. Therefore, this article provides a blueprint for the strategic design of nanofluidic circuits to attain a robust, modular, and tunable control of ion transport under external electrical and mechanical stimuli. [ABSTRACT FROM AUTHOR]

The possibility observation of the electric field controlled multicaloric response through quasi-isostatic compression as a result of the converse piezoelectric effect was demonstrated on the cylindrical type magnetoelectric composite MnAs/PZT. It was shown that an electric voltage of 100 V corresponding to an electric field of E ∼0.3 kV/mm applied to the walls of the piezoelectric component PZT of the MnAs/PZT composite contributes to an increase in the maximum adiabatic temperature change by 0.2 K in the temperature range of the magnetostructural phase transition of MnAs ∼317 K at a magnetic field change of 1.8 T. Numerical analysis using the finite element method has shown that an electric field voltage of 100 V is capable of creating a quasi-isostatic mechanical stress in the region inside a cylindrical PZT tube of ∼3 MPa. Moreover, in the region of weak pressures up to 10 MPa, the contribution to the total adiabatic temperature change from piezo-mechanical compression linearly depends on the electrical voltage that can be used for control by magnetic and caloric properties of multicaloric materials. [ABSTRACT FROM AUTHOR]

Voltage distribution in sub-cellular micro-domains such as neuronal synapses, small protrusions, or dendritic spines regulates the opening and closing of ionic channels, energy production, and thus, cellular homeostasis and excitability. Yet how voltage changes at such a small scale in vivo remains challenging due to the experimental diffraction limit, large signal fluctuations, and the still limited resolution of fast voltage indicators. Here, we study the voltage distribution in nano-compartments using a computational approach based on the Poisson–Nernst–Planck equations for the electro-diffusion motion of ions, where inward and outward fluxes are generated between channels. We report a current–voltage (I–V) logarithmic relationship generalizing Nernst law that reveals how the local membrane curvature modulates the voltage. We further find that an influx current penetrating a cellular electrolyte can lead to perturbations from tens to hundreds of nanometers deep, depending on the local channel organization. Finally, we show that the neck resistance of dendritic spines can be completely shunted by the transporters located on the head boundary, facilitating ionic flow. To conclude, we propose that voltage is regulated at a subcellular level by channel organization, membrane curvature, and narrow passages. [ABSTRACT FROM AUTHOR]

Surface flashover that occurs on the surface of epoxy resin (EP) is one of the main causes of insulation failure in the power system. The newly emerging polar groups on the surface are highly desirable for enhancing the surface flashover performance of EP. Here, we present a facile ultraviolet (UV) irradiation method to enable the controlled introduction of C–OH and C = O groups on the EP surface. The resultant UV-irradiated EPs (UV-EPs) are highly uniform with little variation in surface roughness while exhibiting tunable polar content with the irradiation time. We also present the first systematic investigation into the effect of UV irradiation time on the surface flashover voltage of UV-EPs, with a maximum increase of 23.07% compared to the pristine EP. Mechanistic studies suggest that the enhancement of the surface flashover voltage is mainly dominated by the density of the deep trap, which is strongly dependent on the UV-induced C–OH and C = O groups on the surface. Besides that, the UV-EPs also display long-term stability due to the stable presence of polar groups, which further demonstrates the feasibility of this method for the development of EP with excellent properties. [ABSTRACT FROM AUTHOR]

Alternating current (AC) loss measurement is crucial for the theoretical evaluation and optimization in the fabrication of superconducting AC devices. Lock-in amplifier based on the lock-in phase is commonly adopted and inevitably involves with phase error. In this work, a novel approach for measuring transport AC loss by determining the minimum compensated voltage (MCV) was developed, in which the lock-in amplifier was removed. Since it just uses the voltage signal from an AC voltmeter, it is phase-error immune. Experimental results demonstrated that when using the lock-in amplifier, there existed a system error as the initial phase difference between the sampled (reference) and real current phases, which required careful compensation. In contrast, the phase error no longer needed to be considered by the MCV method, and the AC loss results were obtained much more conveniently with the relative error between the theoretical and the experimental of less than 5%. Finally, the AC loss of a coated conductor spiral wound on an epoxy bar was obtained using the presented approach, demonstrating its low cost, ease of operation, and high accuracy. [ABSTRACT FROM AUTHOR]

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 − 9 m 2 V − 1 s − 1 , which is much higher than the measured DC mobility of 10 − 14 m 2 V − 1 s − 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. [ABSTRACT FROM AUTHOR]

Synaptic behavior simulation in transistors based on MoS2 has been reported. MoS2 was utilized as the active layer to prepare ambipolar thin-film transistors. The excitatory postsynaptic current phenomenon was simulated, observing a gradual voltage decay following the removal of applied pulses, ultimately resulting in a response current slightly higher than the initial current. Subsequently, ±5 V voltages were separately applied for ten consecutive pulse voltage tests, revealing short-term potentiation and short-term depression behaviors. After 92 consecutive positive pulses, the device current transitioned from an initial value of 0.14 to 28.3 mA. Similarly, following 88 consecutive negative pulses, the device current changed, indicating long-term potentiation and long-term depression behaviors. We also employed a pair of continuous triangular wave pulses to evaluate paired-pulse facilitation behavior, observing that the response current of the second stimulus pulse was ∼1.2× greater than that of the first stimulus pulse. The advantages and prospects of using MoS2 as a material for thin-film transistors were thoroughly displayed. [ABSTRACT FROM AUTHOR]

Due to the erratic switching phenomenon of the Si avalanche bipolar junction transistor (ABJT) in the Marx bank circuit (MBC), an explanation of the leakage current trigger mode in the overvoltage state with a lack of displacement current is proposed. There are random switching properties (i.e., switching or non-switching) in the ABJT with emitter–base shorted, triggered by a voltage ramp to the overvoltage state temporarily with dV/dt rate close to 0 V/ns. The experimental conditions and characteristics of erratic behaviors are summarized. The optical visualization of the current channel in an erratic switching state is obtained, and the corresponding physical model of the leakage current trigger mode is established. It shows that the switching event occurs with the change in the position of the conductive channel. The process of emitter electron injection is caused by the leakage current in the overvoltage state instead of the displacement current. Meanwhile, the intensity of this trigger mode is weak, and the instability of the leakage current may cause the failure of switching. The study of erratic switching is of great significance for the working reliability of MBCs and failure analysis of ABJTs. The proposed explanation is validated by the agreement between the simulation results and the experimental observations. [ABSTRACT FROM AUTHOR]

The study of insulation degradation processes is crucial for the reliable operation of power equipment and electronic devices. The phase field method has been widely used in recent years to simulate the degradation process of insulation materials. However, the effect of space charge was ignored. In this paper, a novel phase field method based on the bipolar carrier transfer model is suggested. This model can simulate degradation under different temperatures and DC or combined AC/DC voltage. The cases under AC and combined AC/DC voltage at different temperatures are simulated by COMSOL. Methods to ensure model convergence are proposed. The results show that the field strength distribution under a combined AC/DC field is more uniform, especially for negative polarity. For the same voltage form, temperature and breakdown time show an exponential relationship. The results are consistent with those of previous experimental studies, proving the usability of the model. In addition, the processes of initiation, growth, and breakdown stage of the dielectric degradation process, as well as the stagnation period, are explored theoretically. The stagnation time at low temperatures under combined AC/negative DC voltage is long. The research in this paper is useful for insulation optimization design, condition assessment, and longevity prediction. [ABSTRACT FROM AUTHOR]

As we known waves contain important information, however, to realizing high-precision quantification for ocean exploitation and utilization is challenging. In this paper, we proposed a neural network for wave height detection by training the voltage waveform of a triboelectric nanogenerator (TENG). First, we analyzed the voltage signal obtained using a TENG. Second, we proposed a lightweight artificial neural network model that achieves a minimal monitoring error of 0.049% at low amplitudes and yields better monitoring results than the linear model. The findings presented in this paper enable the measurement of water surface waves and eliminate the influence of external factors on sensor performance. Wave parameters can be obtained using neural networks, and this work provides a new strategy for computational and intelligent applications by using wave data. [ABSTRACT FROM AUTHOR]

Vector inversion generators or spiral generators are compact, high voltage pulse generators consisting of a pair of conducting foils wound in a spiral and a switch. We developed an improved analytical model predicting the time evolution of the output voltage of such spiral generators. Our model (i) takes into account that the current in the switch results from the current on active and passive waveguides and (ii) takes into account the losses of the conductor in equations describing the propagation of voltage and current pulses in both waveguides. The model is compared to experimental results involving different input switches and at different temperatures to investigate the influence of resistive losses on the output voltage. The model is further developed to obtain the time evolution of the current in the switch. Our model is then used to predict the amplitude of the first two peaks of the oscillatory response of spiral generators as a function of a set of dimensionless parameters. [ABSTRACT FROM AUTHOR]

We present super-resolution microscopy of isolated functional mitochondria, enabling real-time studies of structure and function (voltages) in response to pharmacological manipulation. Changes in mitochondrial membrane potential as a function of time and position can be imaged in different metabolic states (not possible in whole cells), created by the addition of substrates and inhibitors of the electron transport chain, enabled by the isolation of vital mitochondria. By careful analysis of structure dyes and voltage dyes (lipophilic cations), we demonstrate that most of the fluorescent signal seen from voltage dyes is due to membrane bound dyes, and develop a model for the membrane potential dependence of the fluorescence contrast for the case of super-resolution imaging, and how it relates to membrane potential. This permits direct analysis of mitochondrial structure and function (voltage) of isolated, individual mitochondria as well as submitochondrial structures in the functional, intact state, a major advance in super-resolution studies of living organelles.

The ability to induce different potentials in different regions of a (bipolar) electrode could transform applications such as on-demand drug delivery, the electrostimulation of biological cells, the development of advanced electroceuticals, and multi-analyte detection devices where different analytes could be wirelessly detected in different regions of a single sensing surface dramatically simplifying the device design. Here, we demonstrate the use of multiple feeder electrodes to control the electric field distribution in solution thus changing the potential induced in different regions of the bipolar electrode depending on the feeder voltage, polarity and feeder electrode position. The principle is demonstrated for the deposition of films of the conducting polymer, Poly(3,4-EthyleneDiOxyThiophene) (PEDOT), without the need for a physical template to control the regions in which polymer deposits. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper discusses an analytical framework to model one‐ and two‐ports in a way which avoids prioritizing either the voltage or the current as model variables. This approach allows for a truly general symbolic treatment of such circuits, avoiding the need to perform repetitive analyses in different working scenarios, and also displays a number of benefits from a theoretical point of view. The key ingredient is a homogeneous version of the Thévenin–Norton theorem for one‐ports which possibly include controlled sources and coupling effects. This paves the way for the introduction of a comprehensive form for the transfer functions and the driving point immittances of two‐ports, accounting for all possible impedance/admittance descriptions of the devices connected at the ports and also of the internal devices. Our framework allows, for example, for a universal definition of reciprocity but also for a straightforward derivation of Middlebrook's formulae in the context of the extra element theorem. Several examples illustrate the results. [ABSTRACT FROM AUTHOR]

In this paper, we consider covering graphs obtained by lifting a tree with a loop at each vertex as a voltage graph over a cyclic group. We generalize a tool of Hell et al. (2020), known as the billiard strategy, for constructing Hamiltonian cycles in the covering graphs of paths. We show that our extended tool can be used to provide new sufficient conditions for the Hamiltonicity of covering graphs of trees that are similar to those of Batagelj and Pisanski (1982) and of Hell et al. (2020). Next, we focus specifically on covering graphs obtained from trees lifted as voltage graphs over cyclic groups Z p of large prime order p. We prove that for a given reflexive tree T whose edge labels are assigned uniformly at random from a finite set, the corresponding lift is almost surely Hamiltonian for a large enough prime-ordered cyclic group Z p. Finally, we show that if a reflexive tree T is lifted over a group Z p of a large prime order, then for any assignment of nonzero elements of Z p to the edges of T , the corresponding cover of T has a large circumference. [ABSTRACT FROM AUTHOR]

This paper presents a design of fully differential chopper amplifier employing the flipped voltage follower (FVF) adaptive biasing technique, focusing on its potential use in biopotential recording applications. The suggested architectural OTA incorporates self-cascoded current mirrors (SCCMs) as the active load to achieve a substantial output swing. The FVFs based adaptive biasing approach for the differential input stage boosts extra current and enhances gain and dynamic characteristics. The chopper amplifier attains a common mode rejection ratio (CMRR) of more than 100 dB through the strategic utilization of chopper modulators and pseudo-resistors. Additionally, this device exhibits characteristics such as accurate and stable gain, high input impedance, and a compact physical footprint. The present study also includes a comparison between the suggested structure and the bio-potential amplifiers discussed in the existing literature. This comparison is based on key metrics such as gain, input referred noise (IRN), CMRR, and input impedance (Zin). The proposed structure yielded a gain of 63.72 dB, an IRN of 0.07nVrms, a CMRR of 127.97 dB and a Zin of 1.54 GΩ. The bio-potential chopper amplifier under consideration was constructed and simulations were performed by utilizing the Cadence Virtuoso Spectre simulator tool at 180 nm CMOS technology node. [ABSTRACT FROM AUTHOR]

In many integrated circuit applications, where large passive resistors are prohibited, a tunable active resistor is necessary. This paper presents a compact and wide-range voltage-controlled grounded resistor that employs MOS transistors only. The design’s foundation is an active adjustable resistor that controls the NMOS transistor’s mode of operation. The proposed design is implemented using 0.18μm TSMC CMOS technology and is validated through post-layout simulations conducted in the Cadence Virtuoso environment. Furthermore, a tunable high-pass filter utilizing the proposed active resistor is also shown. The circuit is powered by 1.5V DC. According to the simulation findings, the resistance varies between 33k Ω and 36G Ω, for an input voltage range −0.7–0.6v. [ABSTRACT FROM AUTHOR]

ABSTRACT The output AC side voltage of traditional full‐bridge inverter is lower than the input DC side voltage, which is limited in low‐voltage power generation. The conventional boost circuit and the modified boost circuit structure are effectively combined, thus putting forward a kind of no leakage current of single‐phase single‐stage booster inverter. The inverter has the characteristics of common ground, which can suppress the leakage current from the structure and avoid the problem of shoot‐through and improve the reliability of the system. The working mode, modulation strategy, and steady‐state performance of the proposed circuit structure are analyzed in detail. Finally, a 250‐W experimental prototype is designed in the laboratory, and the experimental results verify the feasibility and superiority of the proposed inverter. [ABSTRACT FROM AUTHOR]

ABSTRACT Recently, battery energy storage systems (BESS) have gained importance due to the growing introduction of intermittent renewable energy power plants. Although BESS already has multiple applications, the current standard approach presents several drawbacks aggravated by the second‐life batteries use. In order to deal with this issue, the literature proposes the integration of dc/dc converters in the batteries, an approach known as smart battery. However, due to the different capacities of the batteries, the conventional control of smart battery packs does not guarantee a constant dc‐link voltage, because during operation, some dc/dc converters can reach their physical voltage limit. Therefore, this paper proposes an algorithm called offset compensation network (OCN) that guarantees constant dc‐link voltage even when there are saturated converters. Simulations in software PLECS and hardware‐in‐the‐loop experiments validate the proposal. The results prove the improvement of the technology as the possibility to operate with fixed dc‐link voltage, enabling the use of second‐life batteries, OCN algorithm reduces the SOC balancing time in 6.25% and avoids dc‐link voltage variations during the balancing process. Finally, this technology is fully compatible with current power conversion systems, allowing an easy retrofit of standard BESS. [ABSTRACT FROM AUTHOR]

Wet‐design AC subsea power cables are currently rated up to a maximum voltage of 72.5 kV. These high voltage (HV) cables are cost‐effective alternatives to subsea cables kept dry by a protective lead sheath and exhibit superior properties for dynamic applications. However, several vented water trees, degradation phenomena reducing the cable lifetime, are observed in a HV XLPE insulated cable subjected to wet aging in the laboratory. The water trees initiate from a smooth and clean XLPE insulation/semiconductive screen interface. In this paper, we show that voids in the range 15–150 μm are observed in the conductor screen, 50–320 μm from the water tree inception sites. Degradation of the semiconductive material is observed, in the form of porous regions that connect the voids to the water tree inception sites. NaCl impurities are detected on the void surfaces and in the porous regions. These features are proposed to be the pre‐requisites for the formation of the vented water trees observed in this type of cable. The mechanism responsible for the formation of the void and porous regions in the semiconductive cable screen is discussed based on the observations. [ABSTRACT FROM AUTHOR]

Smart home power hardware makes it possible to collect a large number of measurements from the distribution grid with low latency. However, the measurements are imprecise, and not every node is instrumented. Therefore, the measured data must be corrected and augmented with pseudo-measurements to obtain an accurate and complete picture of the distribution grid. Hence, we present and evaluate a novel method for distribution grid monitoring. This method uses smart plugs as measuring devices and a feature propagation algorithm to generate pseudo-measurements for each grid node. The feature propagation algorithm exploits the homophily of buses in the distribution grid and diffuses known voltage values throughout the grid. This novel approach to deriving pseudo-measurement values is evaluated using a simulation of SimBench benchmark grids and the IEEE 37 bus system. In comparison to the established GINN algorithm, the presented approach generates more accurate voltage pseudo-measurements with less computational effort. This enables frequent updates of the distribution grid monitoring with low latency whenever a measurement occurs. [ABSTRACT FROM AUTHOR]

Designing potential architectures by the modification of conventional electrode materials is an effective approach in the development of high performance supercapacitor electrodes. The present study investigated the effect of varying anodization voltages (50, 75, and 100 V) on the morphology and electrochemical properties of titanium nanotubes (TNT). Molybdenum was doped onto TNT using a simple hydrothermal procedure, followed by thermal treatment at 450 °C. The study effectively demonstrated control over the dimensions of the nanotube structure by adjusting the anodization voltage. Additionally, it was found that the tube diameters were increased due to etching during the hydrothermal treatment with the Mo precursor, which potentially enhanced the supercapacitive performance of Mo‐doped TNT. Further, structural analysis revealed that Mo doping improved both crystallinity and electrode stability. With an optimal anodization voltage of 100 V, TNT and Molybdenum‐doped TNT could exhibit capacitance value of 13.34 and 326.54 mF cm−2 respectively, at a current density of 1 mA cm−2. Furthermore, the electrode demonstrated good cyclic stability with 88% capacitance retention and 97% coulombic efficiency after 5000 cycles. An impressive energy density of 87.03 µWh cm−2 and a power density of 799.99 µW cm−2 could be achieved with this sample in an asymmetrical device. [ABSTRACT FROM AUTHOR]

Oxygen redox in layered oxide cathodes for Na‐ion batteries is considered a promising approach for improving the energy density. However, oxygen‐redox‐based cathodes suffer from sluggish kinetics and undesirable structural change during charge/discharge, leading to poor electrochemical performances. Herein, introducing vacancies (□) in the transition metal layers enables the enhanced oxygen redox‐based electrochemical performances in the P3‐type Mn‐based layered oxide cathode is demonstrated. The vacancies can play a role of the local distortion buffers, resulting in the enhanced oxygen redox kinetics and the suppressed structural deformation such as P3‐O3(II) phase transition. The oxygen‐redox‐based P3‐type Na0.56[Ni0.1Mn0.81□0.09]O2 exhibits the large discharge capacity of ≈140.95 mAh g−1 at 26 mA g−1 with a high average discharge voltage of ≈3.54 V (vs Na+/Na). Even at 650 mA g−1, its discharge capacity and average operation voltages delivered ≈122.06 mAh g−1 and ≈3.22 V, respectively. Especially, the small gap of average discharge voltage indicates both improves power‐capability and enhanced kinetics of oxygen redox in P3‐type Na0.56[Ni0.1Mn0.81□0.09]O2. Moreover, the vacancy buffer in the transition metal layers results in the stable cycle‐performance of P3‐type Na0.56[Ni0.1Mn0.81□0.09]O2 with the capacity retention of ≈80.80% for 100 cycles, due to the suppressed P3‐O3(II) phase transition. [ABSTRACT FROM AUTHOR]

ABSTRACT Three‐phase brushless DC (BLDC) motors are cost‐effective and are increasingly used in various speed control applications. The phase voltage, DC‐bus utilization, current ripple, and torque ripple are major performance parameters for a BLDC motor drive. Different pulse width modulation (PWM) methods will diversely influence these parameters. This paper presents the phase voltage, current ripple, and DC‐bus utilization analysis of BLDC motor drive for four PWM techniques and provides a comparative analysis. The current ripple of the BLDC drive is evaluated with low and high switching frequency operations. Phase voltage and DC‐bus utilization of a BLDC motor are evaluated using analytical methods and validated experimentally. The investigation provided in this work are significant for PWM selection and implementation for low and high switching frequency operations. Both low‐ and high‐frequency operations are performed by supplying the BLDC drive from a silicon carbide (SiC) based inverter. These PWM techniques are also compared, considering high and low‐speed applications. Experimental results of SiC inverter‐fed BLDC motor drive are provided to substantiate the proposed work. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper proposed a segment‐compensated printed circuit board (PCB) coil for multirelay wireless power transfer (WPT) system. The PCB coil is designed with variable width to improve the system transfer efficiency, and the segmented compensation method is applied to avoid the high voltage stress on resonant capacitors in case of the multirelay WPT system with a low load resistance operating at a constant voltage frequency. The segmented compensation capacitors are integrated into the PCB coil, so as to constitute the compact coupler used in multirelay WPT system. The optimization procedure of the segment‐compensated PCB coil is also provided. The quality factor of the PCB coil can be improved by optimizing the proportional coefficients of width variation. The voltage of capacitors can be reduced by optimizing the number of segments. A physical variable‐width PCB coil with 3 segments is constructed. The experimental prototypes of the three‐coil, four‐coil, and five‐coil WPT systems are built. The experimental results show that the voltage of the segmented compensation capacitors on each coil is almost uniformly distributed and does not exceed 250 V when the input voltage is 50 V and the load resistance is 10 Ω. Compared with the multirelay WPT system using the equal‐width PCB coil, the multirelay WPT system using the PCB coil designed in this paper has higher output power and higher efficiency. [ABSTRACT FROM AUTHOR]

Designing SPADs with high sensitivity in a wide wavelength range is crucial since the applications utilizing SPAD-based sensors target different parts of the spectrum. Here, we introduce a novel technique to achieve a wider sensitivity spectrum through the insertion of a second multiplication region into the depletion region. Thanks to the proposed method, at 5.5 V excess bias voltage, the fabricated devices achieved a PDP of 78% peak at 500 nm and 25.5% at 850 nm wavelength. At the same excess bias, we measured a normalized noise of 3.7 cps/μm2 and a jitter of 165 ps at 517 nm FWHM. [ABSTRACT FROM AUTHOR]

The aim of the present research is to investigate the effect of ohmic‐assisted extraction (OAE) parameters on the Falcaria vulgaris extract (FVE) properties. Various parameters, including ethanol‐to‐water ratio (0%–100%), voltage gradient (10–30 V/cm), temperature (30°C–60°C), and extraction time (10–30 min), were applied as independent factors. Physicochemical process, antimicrobial properties, and energy analysis were accomplished to achieve OAE optimization. Results indicated that extraction yield (EY) and energy consumption (EC) significantly increased with increasing the voltage gradient and extraction time (p < 0.05). Also, EY significantly increased with increasing of process temperature and the ethanol concentration in the solvent (p < 0.05). The findings demonstrated that as the voltage gradient, process duration, temperature, and ethanol concentration in the solvent were increased, there was a significant initial increase followed by a decrease in both the total phenolic content (TPC) and the DPPH radical scavenging activity of FVE (p < 0.05). The optimization results indicated that the extraction process with an ethanol‐to‐water ratio of 65.5%, voltage gradient of 20.3 V/cm, temperature of 56.6°C, and extraction time of 22.1 min results in maximum extract TPC, DPPH, and EY, and minimum extraction EC. The OAE method showed greater EY and less EC and CO2 production compared to the hydrodistillation (HD) method. In general, OAE caused improved antioxidant and antimicrobial properties of the FVE. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a robust low‐power power‐on‐reset (POR) circuit with dual threshold method is proposed. The current‐based circuit exhibits good robustness with respect to process, voltage, temperature, and supply ramp variations. In contrast to conventional delay‐based pulse generation approaches, a dual threshold method is introduced to generate POR and brown‐out‐reset (BOR) pulse signals, resulting in ultralow quiescent current and a compact area. Implemented in the 55‐nm CMOS process, the proposed circuit achieves an accurate trigger‐point voltage with a temperature coefficient of 90.4 ppm/°C and a deviation to the ramp time of 2.9% for a range from 100 μs to 1 s. Furthermore, the quiescent current and active area are 0.3 nA and 4834 μm2, respectively, making it particularly suitable for energy harvesting systems. [ABSTRACT FROM AUTHOR]

ABSTRACT Direct pulse‐width modulated (PWM) AC–AC converters are rapidly advancing, primarily because of their single‐stage power conversion and reduced footprint, achieved by eliminating the intermediate DC‐link capacitor. Z‐source AC–AC converters (ZSACs) especially have gained attention for their wide voltage range and reduced harmonic currents in applications where only voltage regulation is desired. Meanwhile, voltage regulation in PWM AC–AC converters necessitates effective closed‐loop control methods. Delta‐sigma modulation (DSM) has emerged as a promising technique, outperforming traditional methods. Nevertheless, the conventional DSM technique employs a fixed hysteresis band, resulting in the converter operating at a variable switching frequency. The variable switching frequency increases the switching losses, which puts more thermal stress on the switches. This paper introduces a CSF‐based DSM method for ZSACs that makes use of an adaptive hysteresis band. A four‐step commutation technique is utilized to prevent voltage and current spikes across the bidirectional switches, eliminating the need for snubber circuits. The proposed approach is validated through comprehensive simulation studies and experimental results on a modified quasi‐ZSAC topology using a 200‐W laboratory prototype, demonstrating significant improvements in source and load current total harmonic distortion (THD), dynamic response, and overall system performance while maintaining constant switching frequency. [ABSTRACT FROM AUTHOR]

This research article introduces a 1-bit Full Adder (FA) cell comprising 20 transistors, employing Gate Diffusion Input (GDI) and transmission gate logic. The FA cell is segmented into four modules: the first module encompasses an AND-OR module, followed by a module housing a Multiplexer (MUX) based on transmission gates for Carry Output generation. The remaining two modules are XOR gates dedicated to Sum Output generation. Simulation of the proposed design is conducted on the 45 nm technology node using Cadence Virtuoso and its GPDK 45 nm library. To validate the performance of the proposed design, it is compared against existing full adders. Performance parameters such as power consumption, delay and Power Delay Product (PDP) demonstrate superior performance across voltages ranging from 0.8 V–1.2 V. [ABSTRACT FROM AUTHOR]

Purpose Methods Results Conclusion Very high‐power short‐duration (vHPSD) ablation creates shallower lesions, potentially reducing efficacy. This study aims to identify factors leading to insufficient lesions during pulmonary vein antral isolation (PVAI) with vHPSD‐ablation and to develop an optimized PVAI strategy using this technology.PVAI was performed on 41 atrial fibrillation patients using vHPSD‐ablation (90 W/4 s). Lesion parameters were recorded and analyzed to identify predictors of insufficient lesions. An optimized PVAI strategy, based on these predictors, was tested in subsequent 42 patients.In total, 3099 RF‐applications, including 103(3.3%) insufficient lesions, were analyzed. First‐pass PVAI was achieved in 19/40(47.5%) right PVs and 24/41(58.5%) left PVs. Multivariate analysis identified significant predictors of insufficient lesions: local largest bipolar voltage (Bi‐V), average contact force, baseline impedance, impedance drop, temperature rise, inter‐lesion distance (ILD), and anatomical location (carina or not). An ILD:4‐6 mm increased the risk of insufficient lesions 2.2‐fold, and lesions at the carina increased it 3.6‐fold for both ILD < 4 mm and ILD:4‐6 mm. Local largest Bi‐V was the strongest predictor for insufficient lesions. The optimized PVAI approach, utilizing vHPSD‐ablation with an ILD < 4 mm in non‐carinal areas with Bi‐V < 4 mV, and high‐power ablation‐index guided ablation (HPAI, 50 W, ablation‐index:450–550) in remaining areas, achieved first‐pass PVAI in 92.7% of right PVs and 88.1% of left PVs, using vHPSD‐ablation in approximately 65% of total RF‐applications. The optimized PVAI achieved significantly higher first‐pass PVI rate (p < .0001) with shorter ablation time (p = .04).Appropriate use of vHPSD and HPAI, based on local largest Bi‐V and anatomical information, may achieve high first‐pass PVAI rates in shorter ablation time with minimal energy delivery. [ABSTRACT FROM AUTHOR]

This work characterized different cation- and anion-exchange membranes to improve the efficiency for the electrochemical conversion of Li2SO4 into LiOH and simultaneously recover H2SO4 as a byproduct, an essential process for sustainable alternatives for lithium−ion battery recycling. The membrane's ability to block H+ and OH− migration over the membrane to the feed stream of the electrolyzer was investigated. Simultaneously, the membrane resistance was measured to assess its impact on the cell voltage and overall energy consumption. The best CEM, Sx-2301-Wn, enabled to concentrate LiOH up to 1.7M with a current efficiency (CE) of 77.3%, while Fumasep FAB-130-PK, the best AEM, was able to concentrate H2SO4 up to 0.6M with a CE of 74.6%. The recirculation of LiOH into the middle compartment to maintain a constant pH was also investigated and showed to improve both Li+ (4.2%–8%) and SO42- (5.1%) migration, but pH higher than 3 led to an increased membrane resistance. The results of this work contributed to the selection of a suited membrane and ideal operational conditions for producing LiOH and H2SO4 through a three-compartment membrane electrolysis cell. [ABSTRACT FROM AUTHOR]

This Letter presents the fabrication and characterization of a 2D SnS memristor, proposing its integrate and fire (I&F) model as a potential hardware implementation of neuronal somatic behavior. The memristor comprises a thin layer of tin (II) sulfide (SnS) sandwiched between copper (Cu) electrodes on a silicon (Si) substrate. This structure exhibits an impressive R off : R o n ratio of 103 at a read voltage V r d of 0.25 V with exceptionally low switching V s w and set V set voltages of 0.3 and 0.35 V, respectively, with ∼ 3 order variation between the maximum R max and R min resistances offered during single voltage sweep cycle. We have explained the memristive behavior using the dual ionic conduction mechanism in the SnS active layer. We extracted the real-time band diagram of SnS using ultraviolet photoelectron spectroscopy, explaining the low V s w observed. We propose that the emulation of the I&F artificial neuron model exhibited by the fabricated device could serve as a promising application in the field of artificial neuron spiking. [ABSTRACT FROM AUTHOR]

Distributed power supply access to the distribution network, although it can effectively support the band voltage, will also cause problems such as voltage overruns at the point of grid connection and large network losses, so this paper establishes a reactive power optimization model containing three objectives: network loss, voltage fluctuation rate, and static reactive power generator (SVG) installation capacity in distributed photovoltaic power generation scenarios by taking advantage of the characteristics of SVG that both absorb and send out reactive power. A multiobjective particle swarm algorithm with an adaptive grid and roulette mechanism is introduced to ensure the uniformity and diversity of the Pareto boundaries under the constraint that the output of each device does not exceed the constraints, and to obtain the optimal set of solutions capable of coping with the stochastic fluctuations of distributed power sources. When the algorithm is compared with three other algorithms, such as nondominated sorting genetic algorithm‐II, the results show that it reduces the network loss by about 25% and significantly improves the voltage fluctuation rate. [ABSTRACT FROM AUTHOR]

ABSTRACT Two‐stage single‐phase photovoltaic inverters exhibit a second‐harmonic ripple at the dc‐link voltage, which can cause variations in the terminal voltage of the photovoltaic array, reducing the efficiency of the maximum power point tracking (MPPT). Initially, this work investigates the efficiency reduction caused by the second‐harmonic component using analytical models. Besides, this work explores a control technique to reduce the ripple in the terminals of the photovoltaic module based on real‐time normalization of the dc/dc converter control signal. This technique is compared with conventional control and with the addition of second‐harmonic resonant control. The case study is based on a 4.4‐kVA/220‐V photovoltaic inverter with input for two photovoltaic strings. The results indicate that both techniques are capable of performing the attenuation of the voltage ripple at the terminals of the photovoltaic array, resulting in efficiency gains in the order of 0.74% for the strategy based on resonant control and 0.95% for the proposed normalization technique. In addition, C‐HIL and experimental results prove the reduction in voltage ripple with the normalization and resonant control. As an advantage, the normalization technique is simpler than the second one, because it does not require modification of the control structure of the dc/dc converter. [ABSTRACT FROM AUTHOR]

ABSTRACT Nonisolated three‐level inverter has the problem of leakage current and neutral‐point (NP) potential imbalance in photovoltaic grid‐connected system. Therefore, a new subregional vector‐optimized modulation strategy is proposed, which can be adopted to achieve leakage current suppression and NP potential balance control in full power factor and the range of full modulation ratio. First, a system model is established for the three‐level grid‐connected inverter to analyze the mechanism of leakage current and the factors affecting the NP potential. Aiming at the shortcomings of existing modulation strategies, the three‐level space vector modulation region is redivided, and different voltage vector preselection methods are used in different modulation regions, reduced computing power. In addition, controlling the balance of NP potential, the effect of dead zone effect on the leakage current is further analyzed and improved on the basis of the proposed strategy. Finally, the proposed strategy is compared with the traditional space vector pulse width modulation strategy. The experimental results show that the proposed control strategy suppresses the leakage current below 300 mA and can effectively control the NP potential shift and eliminate the midpoint potential fluctuation. Meanwhile, the control strategy is low in computation and fast in seeking the optimum. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel high‐gain switched capacitor (HGSC) DC–DC converter for carbon neutral energy applications is presented in the scientific paper. It consists of two MOSFET switches, and utilization of a simultaneous switching approach for the switches enables simplified control. The switched capacitor (SC) technique is utilized to extract high gain from the proposed HGSC topology; the basic idea is periodic charging and discharging of the capacitor. The proposed HGSC topology operational mode is carried out in Continuous Conduction Mode (CCM) along with the steady‐state analysis, and different switching stages are discussed in detail. Then, an analysis is carried out to demonstrate the proposed HGSC converter's special feature with other high‐gain converters. An averaging state‐space technique is used to determine the suggested converter's dynamics performance, and a small signal analysis is used to verify its stability. Furthermore, the HGSC topology is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, nonidealities voltage gain is derived. The maximum efficiency of 96.7% is obtained at 150 W output power with the help of the dSPACE 1104 controller. Whenever the HGSC converter is fed with an input voltage supply of 20 V. It generates output voltages between 140 and 240 V. Extensive experimental investigation is carried out on a 200 W laboratory prototype model to verify the practicability and feasibility of HGSC DC–DC converter topology. [ABSTRACT FROM AUTHOR]

The voltage reinjection strategy is an effective solution to improve the voltage quality of the voltage source inverters for high‐power applications. In this article, the fundamentals of voltage reinjection strategy are analyzed to reduce voltage harmonics of the output voltage. Then, a novel voltage reinjection circuit is proposed which can generate a 5‐level voltage to be injected on the voltages of the DC sources. The reinjected voltage can create a 60‐pulse voltage waveform for a three‐phase load. Turn ratio optimization of the reinjection transformer has a significant effect on the improvement of the harmonic situation of the output voltage. Furthermore, the proposed reinjection circuit provides ZVS conditions for the main switches to reduce switching losses considerably. The simulation results indicate that the proposed reinjection circuit can reduce the output voltage THD to 3.16% without any type of filter or modulation, and the load variation does not have a considerable effect on the voltage quality. The experimental results approve the analytical trend and simulation process and also confirm the reinjection circuit performance. According to the results, the proposed method has generated a semi‐sinusoidal voltage waveform with THDV=3.78%$THD_{V}=3.78\%$ in the laboratory. [ABSTRACT FROM AUTHOR]

In the traditional predictive torque control strategy, the cost function considers two different control objectives: stator flux and torque. Therefore, it is necessary to reasonably set the weighting factor to ensure that the optimal voltage vector is accurately selected during the control process, thereby achieving better torque and flux control performance. In view of the complex tuning process caused by traditional predictive torque control setting method of weighting factor, a new weighting factor selection method for permanent magnet synchronous motor control system is proposed in this paper. The derivation process is based on the equivalent transformation between the torque–flux prediction and the voltage vector prediction. If both the cost functions of the torque–flux and voltage vector reach their minimum values, the same output voltage vector will be selected. Compared with previous studies, the algorithm proposed in this paper can find the precise location of the optimal weighting factor without changing the form of the cost function, which simplifies the parameter tuning process. Experimental results are also provided to validate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

The active power control of photovoltaic (PV) inverters without energy storage can flatten the fluctuating power and support the voltage amplitude and frequency of the grid. When operated in grid‐forming voltage‐control mode, because the PV power can change rapidly and widely, the PV inverter needs to track the power commands quickly and precisely. Traditionally, this goal is achieved with the estimation of PV power curve or PI‐based multiple‐loop feedback control, where flexibility, availability and accuracy are not satisfactory. Therefore, a CC/VC‐based power tracking (CVPT) method is proposed, which only uses single‐loop in control. The proposed method does not need to tune multiple loops and can respond faster, which is important for grid‐forming voltage control. Furthermore, the different operating modes due to the limitation of PV maximum power are analysed, and a mode switch method is proposed. Simulation and experimental results demonstrate that the PV inverter can cope with power disturbances from both the power and grid sides and maintain the quality of grid voltage. [ABSTRACT FROM AUTHOR]

This study proposes a cutting‐edge AC/DC converter designed for medium‐power PFC applications. The converter is a single‐phase, single‐stage boost‐push–pull model. It consists of three key components: an interleaved boost, a push–pull, and a resonant tank circuit. The interleaved boost operates in DCM mode and serves as power factor correction. The push–pull converter includes a resonant tank on the secondary side of the transformer to achieve ZVS. The two switches control the boost and the push–pull circuits to create a single‐stage converter. The converter in question provides an array of advantages, such as zero voltage switching (ZVS), an intermediate bus voltage that is independent of the load, and a low‐ripple input current, all of which can be achieved without the need for additional filtering. The present article provides a comprehensive overview of the design procedure, simulation and experimental results, and separate operating modes analysis. To verify the design and simulation results, a 200‐W interleaved boost push–pull converter (IBPPC) prototype is implemented. Finally, because it is crucial to maintain the voltage of the bus capacitor within an acceptable range, this study investigated the impact of load variation on the bus voltage. [ABSTRACT FROM AUTHOR]

In recent years, wide voltage range DC/DC converters have been widely used in telecom power, solar generation and electric vehicle charger applications. Based on this, a new multi‐resonant converter with wide input voltage is proposed here. Compared with the traditional LLC converter, the proposed converter can maintain the output voltage within a narrow frequency regulation range in both under‐resonance and over‐resonance areas. Thus, a wide voltage range can be realized without additional switch components or complex control strategies. The topology and the corresponding working principle of the proposed converter are introduced. In addition, the equivalent model by considering the fundamental wave is established and the influence of the resonance parameters on the voltage gain characteristic is analysed in detail. With these considerations, the resonance parameters are designed. Finally, a 500 W experiment platform is established to verify the effectiveness and feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

This paper proposes a novel non‐isolated ultrahigh step‐down interleaved DC‐DC converter with an extremely extended duty cycle based on the series capacitor and coupled‐inductor techniques. The proposed converter utilizes a three‐winding coupled inductor (TWCI) to enhance the step‐down conversion ratio. In contrast to conventional coupled inductor‐based step‐down converters, its voltage gain improves as the turn ratio approaches unity. Consequently, coupled inductors have significantly lower winding losses. Furthermore, there is no extra constraint on the turn ratio of the TWCI. It results in a highly flexible voltage gain and more design freedom. Other advantages of the employed series capacitor and coupled inductor techniques can be listed as, zero voltage switching (ZVS) condition for all switches, significant reduction of the total switching device power (SDP) and recovery of the energy of leakage inductors. They all reduce power losses and costs. Steady‐state analysis, derivation of voltage gain and design considerations are discussed in detail. Finally, a 200 W, 400‐to‐12 V experimental prototype is implemented to verify the effectiveness and feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

In a modular multilevel converter (MMC) system, the sub‐module capacitors account for a large proportion of the cost, volume, and weight. This paper proposed a method to reduce the total capacitance of MMC based on the combination of boosting the modulation index (m) and second‐harmonic circulating current injection (SCCI). A small amount of full‐bridge sub‐modules was added to conventional half‐bridge sub‐modules (HBSM) based MMC to form the hybrid MMC. The third‐harmonic voltage injection technology was used to increase the m of hybrid MMC without the common‐mode voltage injected on the ac‐side. An optimized SCCI method determined by m was introduced, which limited the root mean square (RMS) of arm current. An improved modulation approach is used to eliminate the coupling effect of third‐harmonic voltage injection and SCCI in boosting m, ensuring that the m increases to 1.15 with the optimized SCCI. Compared with conventional HBSM‐MMC, the proposed method reduced the total capacitance by approximately half when m = 1.15. A comprehensive comparison of different capacitance reduction methods was presented to demonstrate the cost and effect. Simulation and experiment verified the proposed method. [ABSTRACT FROM AUTHOR]

In this article, the homoepitaxial regrowth of AlGaN on AlGaN templates fabricated via chemical mechanical polishing (CMP) on periodically aligned AlN nanopillars is reported on. These templates are lattice relaxed according to X‐Ray diffraction reciprocal space mapping measurements, with a low dislocation density of ≈3 × 108 cm−2. However, the AlGaN surface has hillocks exceeding 104 cm−2. Contrastingly, no hillocks are observed on the homoepitaxially regrown AlGaN on the CMP–AlGaN template and after the UV‐B laser diode (LD) layer structure is crystallized and grown on the homoepitaxially regrown AlGaN. Furthermore, when this wafer is processed for LD fabrication, room‐temperature pulsed oscillation is confirmed in the UV‐B region at a wavelength of 296 nm. The turn‐on voltage and operating voltage also reduce by ≈2 V. [ABSTRACT FROM AUTHOR]

In this work, the fabrication and characterization of a fully functional field‐effect transistor (FET) are addressed based on a non‐intentionally doped GaN‐nanowire FET (NW–FET). Universal conductance fluctuations (UCFs) are observed at temperatures below 140 K. In contrast to other reports in literature, UCFs appear in the analyzed NW–FET only under the influence of an electrical field when applying a gate voltage, while no UCF signatures are observed when performing magnetic‐field‐dependent measurements. The reason is the considerable impact of the applied voltage on the narrow conductive channel of the non‐intentionally doped NW. The electrical field influences the Fermi level as well as the width of the depletion region, both changing the effective impurity distribution which determines the set of possible electron paths. The electric‐field‐induced variation of the set of electron paths correlates with a conductance variation, which leads to the occurrence of UCFs. Furthermore, the reliability of determining the phase coherence length lϕ$l_{\phi}$ from the NW–FET transfer characteristics is analyzed. It is shown that the value of lϕ$l_{\phi}$ is significantly affected by the choice of the gate voltage range due to the current dependence of the magnitude of the UCFs. [ABSTRACT FROM AUTHOR]