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The light-induced transthylakoid membrane potential (ΔΨ) can not only drive the ATP synthesis through the ATP-synthase in chloroplasts but serve as an essential modifier in the acclimation of photosynthesis to fluctuating light conditions. It has been manifested that during photosynthesis, the light-induced ΔΨ is responsive to multiple factors among which the ion channels/transporters (e.g., V–K+, VCCN1, and KEA3) are key to adjust the ion distribution on the two sides of the thylakoid membrane and hence shape the kinetics of ΔΨ. However, an in-depth mechanistic understanding of ion fluxes on adjusting the transthylakoid electric potentials is still unclear. This lack of a mechanistic understanding is due to the experimental difficulty of closely observing ion fluxes in vivo and also hacking the evolution of parameters in a highly intertwined photosynthetic network. In this work, a computer model was applied to investigate the roles of ion fluxes on adjusting transthylakoid electric potentials upon a temporal cycle of a period of high illumination followed by a dark-adapted phase. The computing data revealed that, firstly, upon illumination, the dissipation of the steady-ΔΨ by ∼10 mV is contributed from the V–K+-driven K+ flux whilst ∼8 mV of the steady-ΔΨ is dissipated by the VCCN1-pumped Cl− flux, but there were no appreciable KEA3-evoked variations on ΔΨ; secondly, on transition from high light to darkness, V–K+ and KEA3 are serving as major contributors whereas VCCN1 taking a counterbalancing part in shaping a standard trace of ECS (electrochromic shift), which commonly shows a sharp fall to a minimum before returning to the baseline in darkness. Besides, the functional consequences on components of ΔΨ adjusted by every particular ion channel/transporter were also explored. By employing the model, we bring evidence that particular thylakoid-harbored proteins, namely V–K+, VCCN1, and KEA3, function by distinct mechanisms in the dynamic adjustment of electric potential, which might be mainly importnat under fluctuating light conditions. • Quantitative evaluation of components of transthylakoid electric potential difference. • Quantitative insight into effect of ion fluxes on regulating components of transthylakoid electric potential difference。. [ABSTRACT FROM AUTHOR]

With the maturity of CMOS technologies and their use in low-voltage analog applications, the accuracy of SPICE models is very important. Here, an extremely accurate yet simple form of the charge-sheet model is developed using a symmetric polynomial interpolation of the charge in the channel. This formulation of the drain current retains the same simplicity of the industry-standard surface potential MOSFET models based on the symmetric linearization method (SLM). But, unlike the SLM, it is developed without requiring the linearization of the charge in the channel, hence, the asymmetries and the nonlinearity are accurately accounted for. The model, although more accurate, has the same computational efficiency and easy implementation of the SLM. Finally, the equations of the currents and terminal charges can be worked out to have the same mathematical form as the SLM. [ABSTRACT FROM AUTHOR]

The transthylakoid membrane potential (ΔΨm) is essential because it can drive the ATP synthesis through the CF0-CF1 type of ATP-synthase in chloroplasts as an energetic equivalent similar to 1pH. In addition, a high fraction of proton motive force (PMF) stored as the ΔΨm component is physiologically important in the acclimation of photosynthesis to environmental stresses. It has been shown that ΔΨm is the sum of the Donnan potential difference (ΔΨdn) and the diffusion potential difference (ΔΨd). Specifically, ΔΨdn, ΔΨd, and ΔΨm are strongly associated with the ionic activities near the membrane surface, particularly, the extent of ion binding to the charged/neutral sites adjacent to the membrane surface. However, an in-depth analysis of the effect of altered cationic binding to the membrane surface on adjusting the transthylakoid electric potentials (ΔΨdn, ΔΨd, and ΔΨm) is still missing. This lack of a mechanistic understanding is due to the experimental difficulty of closely observing cations binding to the membrane surface in vivo. In this work, a computer model was proposed to investigate the transthylakoid electric phenomena in the chloroplast focusing on the interaction between cations and the negative charges close to the membrane surface. By employing the model, we simulated the membrane potential and consequently, the measured ECS traces, proxing the ΔΨm, were well described by the computing results on continuous illumination followed by a dark-adapted period. Moreover, the computing data clarified the components of transthylakoid membrane potential, unraveled the functional consequences of altered cationic attachment to the membrane surface on adjusting the transthylakoid electric potential, and further revealed the key role played by Donnan potential in regulating the energization of the thylakoid membrane. The current model for calculating electric potentials can function as a preliminary network for the further development into a more detailed theoretical model by which multiple important variables involved in photosynthesis can be explored. [ABSTRACT FROM AUTHOR]

Recent long term planning studies have demonstrated the important role of variable renewables (VRE) in decarbonising our energy system. However, cost-optimising models do not capture the visual impact of VREs on the landscape which can act to undermine their public acceptability. Here, we use crowd-sourced scenicness data to derive spatially explicit wind energy capacity potentials for three scenarios of public sensitivity to this visual impact. We then use these scenarios in a cost-optimising model of Great Britain's power system to assess their impact on the cost and design of the electricity system in 2050. Our results show that total system costs can increase by up to 14.2% when public sensitivity to visual impact is high compared to low. It is thus essential for policy makers to consider these cost implications and to find mechanisms to ameliorate the visual impact of onshore wind in local communities. [ABSTRACT FROM AUTHOR]

This paper proposes a time-domain method of characteristics to simulate the impulse corona with background space charge, and derives the ordinary differential equations of the space charge generated by the impulse corona along the electric field line. The corresponding boundary conditions, the selection of time step and space step, and the update strategy of space charge are given. The calculation result of the impulse corona onset voltage is consistent with the test result, proving that the background space charge has almost no effect on the impulse corona onset electric field which is obtained by Kaptzov's assumption. The q-u curve obtained by simulation is compared with the test results to verify the effectiveness of the simulation method. The simulation method is used to obtain the development process of space charge during the application of the opposite polarity impulse voltage. By analyzing the space charge distribution during the process of impulse corona, and the corresponding microscopic charge distribution and macroscopic charge amount at different corona states, the characteristics of impulse corona are explained. [ABSTRACT FROM AUTHOR]

A quasi-mixed-potential layered medium Green’s function (QMP-LMGF) is proposed for non-Galerkin surface integral equation (SIE) formulations in the modeling of homogeneous dielectric objects in layered medium. The formulation is derived based on the pilot vector potential approach. In this method, the field-type LMGF in the $L$ -operator is decomposed into two parts, a “vector potential” term in a dyadic form, and a “scalar potential” term in a vector form, to represent the field components from current and charge sources, respectively. Since the proposed two potential terms (vector potential and scalar potential) do not satisfy the Lorenz gauge, we term them as quasi-mixed-potentials. The property of the two potentials is investigated to reveal that the proposed QMP-LMGF is compatible with the vector and scalar potentials in free space. Moreover, due to the continuity of the integration kernels across the interfaces, undesired line integrals are absent in the proposed QMP-LMGF when the objects are straddling different layers. Three popular non-Galerkin SIEs for dielectric objects in layered medium are studied, and the corresponding numerical results are demonstrated to validate the proposed method. [ABSTRACT FROM AUTHOR]

Synchronous rectification (SR) is an effective method to reduce the secondary side conduction loss of CLLC bidirectional resonant converter and improve its efficiency, but the SR driving signal in CLLC converter is hard to determine. Existing SR signal generating methods can be divided into three categories: theoretical calculation, voltage detection, and current detection. Compared with the other two methods, the current detection method has wider applicability and is insensitive to parasitic parameters, but usually requires lossy, bulky and costly current sensors, increasing the cost and size of the converter. This article proposed a SR scheme based on resonant inductor voltage. The polarity of the resonant current is obtained indirectly through the inductor voltage, thereby avoiding the use of current sensors. To handle the false pulses problem caused by parasitic oscillation, a corresponding SR control strategy is proposed. The SR driving signal is then adjusted according to the delay and transient requirements. Experimental results on a 380V/270V 3kW CLLC converter prototype were presented to verify the effectiveness of the proposed SR method. [ABSTRACT FROM AUTHOR]

Worker exposure to high-intensity magnetic fields encountered during bare-handed live-line working on a conductor of an overhead transmission line is a major safety concern. In this article, internal (in situ) electric fields in a live-line worker induced by power frequency magnetic fields were numerically calculated considering realistic exposure conditions, i.e., different working postures on a conductor bundle of an overhead transmission line. The scalar potential finite difference (SPFD) method was adopted to voxel-based human models with realistic postures to calculate internal electric fields inside the models. The results showed that the internal electric fields were far below the basic restriction for occupational exposure stipulated in the International Commission on Nonionizing Radiation Protection guidelines even when the maximum magnetic field exceeded the reference level in the guidelines. [ABSTRACT FROM AUTHOR]

Four-level neutral-point-clamped (NPC) multilevel converter topologies have been proposed and actively studied for low/medium voltage applications. As an inherent issue with these topologies, the voltage balancing of dc-link capacitors is challenging, especially when it operates as a single-end inverter/rectifier with high power factors and high modulation indexes. This article proposes a closed-loop voltage balancing algorithm that is effective and simple to implement with regular level-shifted carriers for a four-level NPC converter, e.g., a π-type converter. This approach is based on the redundant level modulation (RLM), which utilizes one additional voltage level in one switching cycle to gain extra controllability of the capacitor voltages without distorting/undermining the fundamental-frequency output voltage. An algorithm based on analytical expressions and logical operations is developed to achieve a dynamic closed-loop voltage balancing with RLM. The proposed method is effective over the full span of linear modulation indexes (M = 0 ∼ 1.15) and power factors. The proposed algorithm is validated and evaluated in both simulations and experiments. [ABSTRACT FROM AUTHOR]

Many failures of wind turbine blades and electrical equipment due to powerful lightning strikes have occurred. The lightning-induced wind turbine failures that have occurred in recent years can be classified into two main categories. The first is a mechanical component failure. The second is a failure or malfunction of electric or electronic equipment inside or around the wind turbine due to an increase in the potential of the wind turbine grounding system or the electromagnetic induction caused by the lightning strike. In the latter case, the equipment often fails owing to the increase in the potential of the grounding system, the method of suppressing the potential rise by laying a grounding wire vertically or horizontally to the wind turbine foundation is adopted. We propose an empirical expression for the effective length of counterpoises connected to a large grounding electrode such as a wind turbine foundation, and verify the expression using finite-difference time-domain (FDTD) method. [ABSTRACT FROM AUTHOR]

In the voltage source inverter applications, inverter nonlinearities would affect the parameter identification process in many ways. Hence, this article proposes an offline identification method for resistance and dq-axis inductance surface by considering the inverter nonlinearity characteristics. A variable amplitude square-wave injection (VASI) scheme is proposed for the dq-axis inductance identification. The VASI method achieves the inductance identification with a novel data sampling strategy. Meanwhile, it can also establish the inductance surfaces by only a few identified data points with a polynomial fitting algorithm, which greatly reduces the identification time compared with the existing methods. The resistance identification is realized by a slope signal injection method, in which the effect of IGBT voltage drop is analyzed. In order to improve the identification accuracy, the inverter nonlinearities are compensated by a self-learning method considering the zero-axis voltage at different rotor positions. At the same time, the sampling error in zero current zones of abc-phases is researched. In order to verify the effectiveness and generality, the proposed method is carried out on two different test machines and confirmed by finite element analysis. [ABSTRACT FROM AUTHOR]

This article proposes a systematic synthesis method to identify the optimum converter topology for a specified voltage conversion ratio. This gain-oriented converter synthesis is formulated as an inverse problem around the inductor flux balance equations. The proposed synthesis method consists of two processes. A set of distinct converter topologies is first synthesized from the specified voltage conversion ratio by obtaining the solutions for a set of six inverse equations in twelve unknowns. The optimal topology for any intended application can be identified based on the desired performance metrics. The complete synthesis method is illustrated with quadratic buck–boost gain as an example. In total, 25 distinct topologies are synthesized using the first process, and their feasibility is validated by PLECS simulation. In total, three case studies are reported to explain the second process. Ground-referenced output and the minimum number of switches are used as the first two selection criteria in all the case studies. Minimum peak inductor current, minimum component stress factor, and minimum voltage and current stress are the third selection criterion in Case Studies-1, 2, and 3, respectively. The steady-state operations of two optimal converters selected in Case Study-1 were verified experimentally. [ABSTRACT FROM AUTHOR]

An improved approach to determining the kinetic characteristics of electrochemical pressure-driven membrane separation of solutions has been proposed. It is based on the Spiegler friction theory and takes into account the combination of the effects of chemical and electrochemical potentials. The numerical values of the coefficients of friction fωm, f+m, and f+ω in the solvent–membrane, solute (cations)–membrane and solute (cations)–solvent systems, respectively, were found using the example of the electrochemical pressure-driven membrane separation of aqueous solutions of CuSO4, Ni(NO3)2, and Fe(NO3)3 with concentrations of 1 × 10–2, 2 × 10–3, and 1 × 10–5 mol/L, respectively, using MGA-95 and MGA-100 membranes. Empirical coefficients to determine approximating curves were also determined. It was detected that the absolute values of these coefficients increased with increasing applied electric potential in almost all cases. An exception was mass transfer through the near-cathode membranes in the separation of the Fe(NO3)3 solution. The absolute values of the coefficients of friction were lowest in the separation of the CuSO4 solution and highest in the separation of the Fe(NO3)3 solution. The derived approximating dependences of the coefficients of friction on the electric potential were used to solve the inverse problem to find the retention factors and the outlet solvent flux. This can be efficiently used to predict the mass-transfer mechanism and calculate the characteristics of electromembrane units. [ABSTRACT FROM AUTHOR]

This article presents a compact quantum threshold voltage (${V}_{\text {th}}$) shift model for a junctionless (JL) quadruple-gate (QG) FET in subthreshold region. Starting from our previous compact model for JL QG FET, the potential and the classical electron density are calculated. Considering 2-D quantum confinement, four types of quantum systems are modeled as a combination of quantum harmonic oscillator (QHO) and quantum well with bottom perturbation potential, depending on the device dimensions. Electron subband energy level for each quantum system is analytically derived to get quantum electron density. The quantum ${V}_{\text {th}}$ shift model is obtained by the ratio of quantum and classical electron line density. The modeling results are validated by 3-D numerical device simulation. It is shown that the proposed model can accurately capture the quantum ${V}_{\text {th}}$ shift in JL QG FET where both fin width and height are 3 nm. Therefore, the proposed ${V}_{\text {th}}$ shift model can be used for quantum corrections for circuit simulation of JL QG FETs. [ABSTRACT FROM AUTHOR]

We discuss the theoretical basis of the Boltzmann transport equation (BTE) and the Monte Carlo (MC) simulation scheme to take into account the discrete nature of impurities in semiconductor substrates. This is achieved by explicitly considering the self-consistent coupling between the BTE and Poisson’s equation and by separating the impurity potential into long- and short-range parts in those equations. We show that the Hartree potential is represented by the long-range part of the potential, whereas the scattering potential for the BTE is naturally derived within the framework, rather than an ad hoc assumption. The proposed scheme is validated by showing that MC simulations with discrete impurities in bulk can reproduce the conventional simulation results with the “jellium” impurity. Also, by including both static and dynamic potential fluctuations, the MC simulation can predict the correct mobility even under discrete impurities. [ABSTRACT FROM AUTHOR]

In order to accelerate the semiconductor device simulation, we propose to use a neural network to learn an approximate solution for desired bias conditions. With an initial solution (predicted by a trained neural network) sufficiently close to the final one, the computational cost to calculate several unnecessary solutions is significantly reduced. Specifically, a convolutional neural network for the metal–oxide–semiconductor field-effect transistor (MOSFET) is trained in a supervised manner to compute the initial solution. In particular, we propose to consider a device template for various devices and a compact expression of the solution based on the electrostatic potential. We empirically show that the proposed method accelerates the simulation significantly. [ABSTRACT FROM AUTHOR]

The ion-sensitive field-effect transistor (ISFET) is a type of electrochemical sensor with a wide range of applications. They offer advantages of being compatible with standard CMOS technology, a miniaturised form-factor, robustness, scalability and low power requirements to name a few. There are now many architectures and design strategies to construct ISFET-based systems in CMOS, and the appropriate choice of these depends heavily on the specifications of the intended application. This tutorial aims to give a designer the knowledge needed to make the best decisions for the required specifications by providing a background in theory and an overview of design trade-offs and existing approaches. Example designs which maximise performance in particular applications are discussed and practical considerations for simulation, layout and implementation are presented. [ABSTRACT FROM AUTHOR]

The linear–nonlinear step load control is proposed to meet the requirements of the pulse load. The nonlinear optimal step control from absolute no-load to full-load is able to force the converter to reach the full-load steady-state operation point with the minimum output voltage drop and minimum settling time. The key is to calculate the initial switching frequency and the duty cycle of the first switching period depending on the load condition. The proposed method is realized by analytic geometry analysis on the state trajectory and confirmed in a 6.6-kW 1-kV/48-V SiC LLC converter. From no-load to full-load, the output voltage drops by 2.24 V and the settling time is 0.76 ms, which reduce by 18.8% and 79.3% compared with the conventional linear control, respectively. Under 100-Hz pulse load with the duty cycle of 30%, the output voltage drop is limited within 2.30 V and overshoot by 1.68 V. [ABSTRACT FROM AUTHOR]

Power electronic (PE) penetration in energy networks has been increasing rapidly in recent years due to the campaign to rely on distributed generation as a clean, sustainable energy source. This increase leads to new challenges and stability problems occurring because of the increase in the harmonic current injected into the power network. To study and address such issues, accurate and computationally efficient models are required. In this article, a Hammerstein–Wiener-based approach is proposed to develop black-box models for PE devices capable of capturing the devices’ harmonic characteristics. A novel method based on magnitude square coherence is also proposed to compare the results of different models in the frequency domain. The method is implemented in a simulation environment and was further tested and validated through laboratory measurements. [ABSTRACT FROM AUTHOR]

Macaroni channel structure is used popularly in 3-D NAND flash memory where the memory cells are connected in series. A model of inner potential in the subthreshold regime for the whole string of three transistors is presented and verified with the TCAD simulations. By using this model, the operation of the string and the interaction between transistors are investigated. Relative position dependence between transistors is also investigated. The obtained model can be used to predict the interference effect and be helpful in the design of the 3-D NAND flash memory cell. [ABSTRACT FROM AUTHOR]

One important problem in the operation of medium voltage networks is the detection of a single-line-to-ground fault in its incipient state, when the fault resistance values are very high. In a medium voltage (MV) distribution network with a neutral grounding resistor (NGR), one of the methods employed to discriminate a single line-to-ground fault is the use of an overcurrent relay with an operating characteristic adjusted according to the effective value of the current flowing through the limiting resistor. In case of a single line-to-ground fault with a high fault resistance value, the correct tripping settings of the protective relay require the precise computation of this current. In comparison to the assumptions made by the models from the literature--the three-phase voltage system of the medium voltage busbars is symmetrical and there are no active power losses in the network insulation--the model proposed in this paper considers the pre-fault zero-sequence voltage of the medium voltage busbars and the active power losses in the network insulation, which is necessary in certain fault conditions where the use of the former leads to unacceptable errors. [ABSTRACT FROM AUTHOR]

An above-threshold I–V model is developed for short-channel double-gate (DG) MOSFETs. It is a non-gradual channel approximation (non-GCA) model that takes into account the contribution to carrier density from the encroachment of source–drain bands into the channel. At low-drain bias voltages, the effect appears as a gate-voltage-dependent reduction of channel resistance, with stronger effects at low gate overdrives. At high-drain biases, the intersection of source band encroachment with the gate-controlled channel potential leads to a point of virtual cathode a small distance from the source. By incorporating the depletion of carriers in the source and drain regions into the boundary conditions, the ${I}_{\text {ds}}-{V}_{\text {ds}}$ and ${I}_{\text {ds}}-{V}_{\text {gs}}$ characteristics generated by the model are shown to be consistent with TCAD simulations. [ABSTRACT FROM AUTHOR]

Particle tracking simulations with space charge effects are very important for high-intensity proton rings. Since they include not only Hamiltonian mechanics of a single particle but also constructing charge densities and solving Poisson equations to obtain the electromagnetic field due to the space charge, they are extremely time-consuming. We have newly developed a particle tracking simulation code that can be used in graphics processing units (GPUs). GPUs have strong capacities of parallel processing so that the calculation of single-particle mechanics can be done very fast by complete parallelization. Our new code also includes the space charge effect. It must construct charge densities, which cannot be completely parallelized. For the charge density construction, we can use “shared memory,” which can be accessed very fast from each thread. The usage of shared memory is another advantage of GPU computing. As a result of our new development, we increase the speed of our particle tracking, including the space charge effect approximately ten times faster than that in the case of our conventional code used in CPU. [ABSTRACT FROM AUTHOR]

Safe and effective exploitation of lithium ion (Li-ion) batteries requires advanced battery management systems. This article proposes a computationally efficient, control-oriented model of a Li-ion cell. The model describes the spatial nature of both the chemical species and temperature dynamics in a computationally efficient way. The method takes advantage of the algebraic structure that arises from the distributed nature of the model. We show that, by discretizing the model partial differential equations with a finite difference method, the coupling equations take a semiseparable structure for which an efficient algebra exists. This approach yields an efficient modeling tool that can be employed to design model-based estimation and control algorithms. The proposed model is validated against a high order computational fluid dynamics model showing accuracy and efficiency. [ABSTRACT FROM AUTHOR]

An electric potential appears at floating wires located within a strong electric field. This phenomenon can be used to supply small isolated communities situated close to Extra-High Voltage transmission lines. This non-conventional distributed generation system has been studied for the last years. However, to improve the power generation system the optimal position of the floating wires, number of wires used, bundle radius, and type of wires must be properly identified. This paper presents a mathematical model solved with genetic algorithm to design a collector system with optimized induced voltage and minimized project cost, identifying the optimal reactor used for voltage regulation. The algorithm was applied to design a collector system that can tap-off 100 kW from a 230 kV transmission line. The trade-off between objectives and the Pareto optimal solutions were evidenced via several simulations using the weighting sum approach. These results allowed to identify a final geometry according to a-posteriori designer preferences. [ABSTRACT FROM AUTHOR]

Experimental observations have long-established that there exists a smooth roll-off or knee transition between the temperature-limited (TL) and full-space-charge-limited (FSCL) emission regions of the emission current density-temperature (J – T) (Miram) curve, or the emission current density-voltage (J – V) curve for a thermionic emission cathode. In this article, we demonstrate that this experimentally observed smooth transition does not require frequently used a priori assumptions of a continuous distribution of work functions on the cathode surface. Instead, we find that the smooth transition arises as a natural consequence of the physics of nonuniform thermionic emission from a spatially heterogeneous cathode surface. We obtain this smooth transition for both J – T and J – V curves using a predictive nonuniform thermionic emission model that includes 3-D space charge, patch fields (electrostatic potential nonuniformity on the cathode surface based on local work function values), and Schottky barrier lowering physics and illustrates that a smooth knee can arise from a thermionic cathode surface with as few as two discrete work function values. Importantly, we find that the inclusion of patch field effects is crucial for obtaining accurate J – T and J – V curves, and the further inclusion of Schottky barrier lowering is needed for accurate J – V curves. This finding and the emission model provided in this article have important implications for modeling electron emission from realistic, heterogeneous surfaces. Such modeling is important for an improved understanding of the interplay of emission physics, cathode materials engineering, and the design of numerous devices employing electron emission cathodes. [ABSTRACT FROM AUTHOR]

This article presents an analytical method to derive an optimum converter topology for a specified voltage conversion ratio (G). An optimum topology for any given G can be identified after obtaining the comprehensive pool of converter topologies. This gain-oriented converter synthesis is formulated as an inverse problem around the principle of inductor flux balance. A step-by-step method is proposed to solve the inverse problem and obtain a comprehensive set of non-redundant converter topologies for any given voltage conversion ratio. Consequently, the number of possible converter topologies for a specified voltage conversion ratio is also identified. The optimum converter topology is chosen from the comprehensive set based on three selection criteria, viz., ground-referenced output, a minimum number of switches, and minimum peak inductor current. The proposed solution methodology is illustrated with quadratic boost and quadratic buck gains as case studies. A comprehensive set of non-redundant topologies is identified in both cases. The steady-state operations of all the topologies are studied with PLECS simulation. Based on the selection criteria, an optimum topology is selected in each case, and their steady-state operation is verified experimentally using lab-developed prototypes. [ABSTRACT FROM AUTHOR]

This article presents the implementation and performance evaluation of a model predictive control (MPC) for three-phase (3σ) transformerless interconnected five-level power electronic converters (PECs). The proposed MPC employs a discrete-time model of five-level PECs to predict future values of the grid-injected currents and ground potential. Predicted values of the grid-injected currents and ground potential are used to set the reference signals to minimize a cost function, which is formulated in terms of the command and actual values of grid-injected current and ground potential. The proposed MPC is implemented for transformerless interconnected diode-clamped and flying-capacitor five-level PECs under different conditions. Test results show that the developed MPC can operate transformerless interconnected PECs to ensure accurate, dynamic, and fast responses to changes in the power delivered to the host grid. Furthermore, the MPC demonstrates a good ability to minimize ground potentials during steady state and step changes in the power delivered to the host grid. [ABSTRACT FROM AUTHOR]

The processes of ion transport are studied using the model of a single ion-exchanger particle. The MA-40 anion-exchange membrane is chosen as a model. The fundamental difference between the membrane model of the ion exchanger and the ion exchanger itself is that the electric potential inside the solid phase can be measured on the membrane due to a special design of the measuring device. This measurement is impossible in the ion exchanger itself. Due to the indicated feature of the chosen membrane model, it became possible to propose a simple mathematical model of the process for analyzing the potential dynamics graphs. The time-varying potentials are measured on both sides of the membrane using the AgCl/Ag reference electrodes. The dynamics of time changes in the potentials of the membrane surfaces is recorded. The time change in the membrane potentials reflects the process of establishing the ion-exchange equilibrium at the membrane-solution interface. The mechanism of transfer processes across the interphase boundary is discussed. [ABSTRACT FROM AUTHOR]

Knowing exactly potentials’ distribution in pixels is a key to ensure that electronretention and transport enable a good pixel operation. Moreover, it is also a key parameter for controlof charge storage capabilityor fullwell capacity, strongly driven by potential barriers. In this article, a new method is presented to characterize potentialswithin pixels from test structure measurements. The proposed method enables to extract potential under a gate, pinning potential of photodiodes or memories, and any potential along the charge path. It is based on the use of the Enz–Krummenacher–Vittoz (EKV) model together with measurements on adequate test structures. Thanks to the so-called “ Y function series resistance correction,” the method can even be applied to test structures including devices in series as in real pixel. The method proposed here is assessed using Sentaurus technology computer-aided design (TCAD) simulation results. Such potentials extracted on the test structure can be used for process and pixel developments, devicemonitoring, reliability studies, and TCAD calibration. [ABSTRACT FROM AUTHOR]

In this brief, we computationally examine electrical characteristics of stacked gate-all-around Si nanosheet MOSFETs (GAA NS-FETs) with and without metal sidewall (MSW) source/drain (S/D) by increasing the number of channels (NCs) and their impacts on digital circuits. The ON-current (ION) and circuit performances of the NS-FETs without the MSW S/D are limited to three channels due to the electrostatic potential decreasing from the top contacts to the bottom S/D side of NS-FETs; however, the MSW S/D can improve the Ion with increasing the NCs over three channels because of low resistivity of tungsten (5.6 × 10−6 Ω ⋅ cm) in the sidewall of S/D and then the circuit performances can be boost by the MSW S/D structure of the stacked GAA NS-FETs over three channels. For example, up to six channels of the NS-FETs with the MSW S/D, the frequency of ring oscillator is 57% increase, compared with the case without MSW S/D. The results of this study can be considered to design the S/D structure of the stacked GAA NS-FETs in emerging device technologies. [ABSTRACT FROM AUTHOR]

Objective: This paper develops a novel approach for fast and reliable reconstruction of EEG sources in MRI-based head models. Methods: The inverse EEG problem is reduced to the Cauchy problem for an elliptic partial-derivative equation. The problem is transformed into a regularized minimax problem, which is directly approximated in a finite-element space. The resulting numerical method is efficient and easy to program. It eliminates the need to solve forward problems, which can be a tedious task. The method applies to complex anatomical head models, possibly containing holes in surfaces, anisotropic conductivity, and conductivity variations inside each tissue. The method has been verified on a spherical shell model and an MRI-based head. Results: Numerical experiments indicate high accuracy of localization of brain activations (both cortical potential and current) and rapid execution time. Conclusion: This study demonstrates that the proposed approach is feasible for EEG source analysis and can serve as a rapid and reliable tool for EEG source analysis. Significance: The significance of this study is that it develops a fast, accurate, and simple numerical method of EEG source analysis, applicable to almost arbitrary complex head models. [ABSTRACT FROM AUTHOR]

Darwin’s model is a reduced form of Maxwell’s equations, where radiations are neglected, while inductive, resistive, and capacitive effects are still taken into account. In this article, we propose a method for the efficient modeling of electrically long, thin wires using a Darwin-based integral equation approach, thus keeping the number of DoFs and runtime low. This model provides further numerical techniques to efficiently take into account special inhomogeneities via the modification of the Green’s functions unlike in full-wave models. The benefits are discussed through the example of the automotive CISPR 25 measurement setup. [ABSTRACT FROM AUTHOR]

A model order reduction method to recursively compute a Cauer ladder network from static finite-element solutions is extended for use with a double vector potential formulation, which decreases difficulties in solving the finite-element equation system. In addition, the connection between the boundary condition and the viability of the solution is demonstrated. Finally, the method is applied to two examples. [ABSTRACT FROM AUTHOR]

In the absence of wave propagation, transient electromagnetic fields are governed by a composite scalar/vector potential formulation for the quasi-static Darwin field model. Darwin-type field models are capable of capturing inductive, resistive, and capacitive effects. To avoid possibly non-symmetric and ill-conditioned fully discrete monolithic formulations, here, a Darwin field model is presented, which results in a two-step algorithm, where the discrete representations of the electric scalar potential and the magnetic vector potential are computed consecutively. Numerical simulations show the validity of the presented approach. [ABSTRACT FROM AUTHOR]

The nonlinear governing equations on the coupling between electromechanical fields and charge carrier in a thermal equilibrium piezoelectric pn junction subjected to asymmetric mechanical loads are established in this article. Effect of mechanical loads on the basic physical parameters of a piezoelectric pn junction, such as potential barrier region width, contact potential difference, electric potential, and carrier concentrations are analyzed numerically. Results show that asymmetry compressive stresses exert more influence on the movement of the potential barrier region’s boundary and the migration of carrier compare to asymmetry tensile stresses. It is also found that asymmetry compressive stresses lead to a pn junction with a thin potential barrier region which enhances the chance of carrier’s passing through of potential barrier region. The obtained results are useful in reducing the disadvantage of capacitance on rectification characteristic and can be used to tune the I – V characteristic of the pn junction working with bias voltage. [ABSTRACT FROM AUTHOR]

A shot noise suppression process of the emission-limited or the “soft” reset in an image sensor is investigated by analytically solving a master (Kolmogorov–Bateman) equation for a continuous-time Markov chain with correlated carrier emission rates. An explicit form of the probability distribution function, the hypoexponential type, is derived. An analytical form of the soft-reset (SR) noise is derived as the second-order moment, that is, variance, of the distribution function. It describes all the main characteristics of the SR noise previously reported; time-dependent shot noise suppression approaching an asymptotic limit of the half amount of noise charges as those of the fast or “hard” reset. The noise suppression mechanism is attributed to cascaded transitions of the storage node potential on a potential ladder giving the variance composed of a uniformly decreasing convergent series. The noise reduction factor is shown to be determined by the ladder spacing of a single-carrier charging potential. From the first-order moment analysis, an average time or lifetime dependence identical to that of the deterministic diode-decay equation is derived. Thus, the SR noise can be characterized by the governing probability law and its moments. [ABSTRACT FROM AUTHOR]

A macaroni type gate-all-around polysilicon transistor with a single grain boundary (GB) is precisely simulated to elucidate the impacts of the variation of GB width (WGB) and trap density (Dt) on its transfer characteristics. At the weak inversion region, the shift of the threshold voltage and subthreshold swing caused by GB are almost determined by the total number of the trap state in the GB (∝ WGB × Dt) because the potential barrier is simply the function of total trap state number. On the other hand, the drain current in the strong inversion region (ID,INV) is not simply the function of WGB × Dt, but more sensitive to the variation of Dt than that of WGB. For example, ID,INV becomes half when Dt increases five times (from 0.2 × 1021 to 2 × 1021 cm−3 ⋅ eV−1) with WGB × Dt kept constant (WGB reduces from 5 to 1 nm). At the strong inversion region, the higher Dt makes the deeper potential barrier at the center of GB, which reduces ID,INV further. Accordingly, the activation energy of ID,INV also has stronger dependence on Dt as compared to WGB. Finally, it is shown that abovementioned characteristics are available even in the multiple-GB cases when the grain size is twice larger than the GB width. [ABSTRACT FROM AUTHOR]

In this work, a double-gate (DG) metal–oxide–semiconductor field-effect transistor (MOSFET) with raised source and drain (RSD) regions is utilized for application of one-transistor (1T) dynamic random access memory (DRAM) through series of validation by technology computer-aided design (TCAD) device simulation. The engineered device shows less short-channel effects (SCEs) and unwanted interband tunneling compared with the usual DG MOSFETs. As a 1T DRAM device, it demonstrates longer retention time (Tret) and larger sensing margin (SM). The designed 1T DRAM achieves Tret ~ 330 and ~ 200 ms at 27 °C and 85 °C, respectively, at 50-nm channel length. Also, the device shows higher current ratio and consumes low power (84.7 nW for write “1”) and energy (2.16 × 10−15 J for read “1” and 1.5 × 10−17 J for read “0” operations). Furthermore, it is revealed that low-κ spacer has an effect of increasing Tret in the device. [ABSTRACT FROM AUTHOR]

The quantum framework of the time-dependent density functional theory (TDDFT) for analyzing nanostructured devices is reviewed, and alternative methods for incorporating induced electromagnetic fields into the theory are discussed. To capture the retardation effects in larger electronic structures, the TDDFT equations can be formulated by applying the Lorenz gauge-fixing condition to the induced scalar and vector potentials (analogous to macroscopic formulations used in antenna theory). Evaluating the retarded potentials via radiation integrals, however, rapidly becomes the computational bottleneck within the TDDFT time-marching framework if done in a brute-force manner. This article demonstrates that 3D space or 4D space-time fast Fourier transform (FFT) schemes can be adopted to accelerate these computations and reduce the costs of evaluating the potentials below the typical computational bottleneck of TDDFT. Thus, FFT-accelerated Lorenz gauge retarded potentials become an attractive candidate for replacing the conventionally used electrostatic-induced scalar potential within TDDFT. [ABSTRACT FROM AUTHOR]

The piezoelectric spherical transducers have attracted extensive attention in hydroacoustics and health monitoring. However, most reported piezoelectric spherical transducers are merely analyzed by the thin spherical shell theory, which is unsuitable for the gradually increased spherical shell thickness. Therefore, it is necessary to develop the radial vibration theory of the piezoelectric spherical transducer with arbitrary wall thickness. Herein, an exact analyzing model for the radial vibration of the piezoelectric spherical transducer with arbitrary wall thickness is proposed. The radial displacement and electric potential for radial vibration of the piezoelectric spherical transducer are precisely given, and then, the electromechanical equivalent circuit is obtained. Based on the electromechanical equivalent circuit, the resonance/antiresonance frequency equations of piezoelectric spherical transducers in the radial vibration are obtained. Besides, the relationship between performance parameters and wall thicknesses is discussed. The wall thickness has a significant influence on the performance parameters of the spherical transducer. The accuracy of the theory is validated by comparing the results with the experiment and finite element analysis. [ABSTRACT FROM AUTHOR]

In the control of variable flux reluctance machine (VFRM) excited by zero-sequence current, neglecting the zero-sequence resistive voltage drop would cause a large calculation deviation of the stator voltage, which can saturate the inverter and influence the switching from constant torque region to flux-weakening region. To solve with this problem, a flux-weakening control method considering the zero-sequence resistive voltage drop for VFRM is proposed. Firstly, the relationship between dq-axis voltages, zero-sequence voltage and the maximum voltage is presented. Secondly, based on the deduced voltage constraint, the calculation of optimal reference currents in flux-weakening region is presented by using Lagrange multiplier method. Since the zero-sequence voltage is considered, the calculation accuracy of the stator voltage and the utilization rate of DC link voltage are improved, which improves the output power capability. Finally, the proposed method is verified by the experimental results. [ABSTRACT FROM AUTHOR]

Objective: Electromagnetic recordings are useful for non-invasive measurement of human brain activity. They typically sample electric potentials on the scalp or the magnetic field outside the head using electroencephalography (EEG) or magnetoencephalography (MEG), respectively. EEG and MEG are not, however, symmetric counterparts: EEG samples a scalar field via a line integral over the electric field between two points, while MEG samples projections of a vector-valued field by small sensors. Here we present a unified mathematical formalism for electromagnetic measurements, leading to useful interpretations and signal processing methods for EEG and MEG. Methods: We represent electric and magnetic fields as solutions of Laplace's equation under the quasi-static approximation, each field representable as an expansion of the same vector spherical harmonics (VSH) but differently weighted by electro- and magnetostatic multipole moments, respectively. Results: We observe that the electric and the magnetic fields are mathematically symmetric but couple to the underlying electric source distribution in distinct ways via their corresponding multipole moments, which have concise mathematical forms. The VSH model also allows us to construct linear bases for MEG and EEG for signal processing and analysis, including interference suppression methods and system calibration. Conclusion: The VSH model is a powerful and simple approach for modeling quasi-static electromagnetic fields. Significance: Our formalism provides a unified framework for interpreting resolution questions, and paves the way for new processing and analysis methods. [ABSTRACT FROM AUTHOR]

The article is the continuation of the work devoted to the numerical study of processes in the single-phase ac plasma torch operating at low current (up to 10A RMS). The main attention is paid to the analysis of the flow pattern and the behavior of gasdynamic parameters. The effects of flow acceleration and rarefaction of near axial arc core are shown. The effects of the transformation of gasdynamic structures typical for cold flow (e.g., vortex behind the back step), as well as the appearance of new structures (e.g., vortexes in the jet periphery), are demonstrated and discussed. An explanation is given for the effect of the increase of the arc voltage drop with the increase of the flow rate of supplied air, associated with the increase of the medium electric resistance. The presented results are in accordance with the experimental data on the voltage drop in a conventional ac plasma torch. [ABSTRACT FROM AUTHOR]

This study investigates different geometry configurations for obtaining photoplasma in a gas cell of Na–Ar mixture. For this purpose, 2-D simulations with the fluid model of plasma have been conducted for single-chamber and two-chamber cells. For the studied range of pressure, the drift-diffusion approximation has been used. The simulation model is based on solving the continuity, momentum balance for charged particles, coupled with electron energy balance equation and the Poisson equation. Detailed plasma chemistry has been considered, and plasma parameters have been obtained, such as electron density and temperature, and the electric potential of the plasma. The obtained results show the effectiveness of the two-chamber cell configuration over the single-chamber one in generating a notable electromotive force (EMF). [ABSTRACT FROM AUTHOR]

In order to efficiently manage display power, there is a need for a system that can accurately predict the power consumed according to the displayed image. Existing AMOLED display power models do not consider the effects of I–R drop, which is a voltage drop along the VDD line. Therefore, when the existing power model is applied to a recent AMOLED display panel, which has a large physical size and uses a large current, power consumption cannot be accurately predicted. In this article, we propose a new model to compensate for the I–R drop and present a more accurate method for predicting AMOLED display power consumption by applying it to existing AMOLED display power models. To verify this, we conducted extensive experiments for various image databases on AMOLED display panels of Samsung Galaxy S7 and S9. When comparing the proposed display power model connected with the I–R drop model with conventional power models, it is confirmed that the proposed power model improves the accuracy by up to 70.3% over them. [ABSTRACT FROM AUTHOR]

In this article, an improved dc capacitor voltage balancing control is proposed for single-phase cascaded H-bridge (CHB) multilevel converters. Compared with conventional voltage balancing control methods, the proposed scheme has a comprehensive consideration of three aspects while balancing the capacitor voltages among H-bridges: coupling effect elimination, reactive power balancing, and dynamic performance improvement. First, the system mathematical model in the d–q reference frame is derived, and the relationship among duty cycle modifications of H-bridges is revealed to eliminate the coupling effect of voltage balancing control on the current control loop. Then, based on the H-bridge power model, a quantitative solution for reactive power balancing is presented to design the reactive duty cycle modifications. In order to enhance the dynamic performance of voltage balancing control, a dynamic references design method is adopted to evaluate the active duty cycle modifications. Finally, both simulation and experimental results are presented to validate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Conventional superjunction (SJ) structures are composed of p- and n-type doped pillars extending longitudinally as linear stripes (LSs). The reduced surface field (RESURF) effect in these structures is essentially due to a 2-D depletion. A 3-D RESURF is expected to be better than a 2-D RESURF and may further improve the BV − RDS(on),sp tradeoff for SJ devices. A natural 3-D RESURF structure is a core-shell (CS) SJ structure with a cylindrical unit cell. To identify and leverage the advantages that a 3-D RESURF can offer, the CS SJ is theoretically and numerically analyzed in this article. We develop an analytical model that results in closed-form expressions for the electric field profiles in both CS and LS structures. A very close agreement is observed between the analytical results and numerical simulations. The efficacy of 2-D and 3-D RESURF is compared using the model, and it is found that neither of these designs is universally better. The superior design is determined by the fabrication technology limitations. For trench refill type technologies, the CS design can offer substantial improvement, but, for lithography limited technologies, the CS design shows a significant deterioration in BV − RDS(on),sp tradeoff compared with the LS design. [ABSTRACT FROM AUTHOR]

This article investigates the effect of a simplified procedure, referred here as Rusck's approximation, which consists in obtaining the electrical potential at a given height by multiplying the vertical electric field computed at ground surface by the height considered, instead of integrating the vertical electric field from the ground surface up to the given height. This procedure is currently considered by several authors but, so far, has not been investigated in detail. The article shows that this approximation leads to significant deviations at close range from the strike but provides accurate results if the distance from the strike is higher than three times the height of the point considered. The article also shows that the distance between the line and the flash must be higher than three times the line height to obtain lightning induced voltage peak-values sufficiently high to produce line flashovers, as otherwise the flash will strike the line directly. As Rusck's approximation provides accurate results under such condition, it can be used for the assessment of indirect lightning performance of aerial power lines without any significant loss of accuracy. [ABSTRACT FROM AUTHOR]