Search

Polyelectrolyte brushes (PEBs) are commonly used to modify surface that have attracted great research interest. The dielectric permittivity of the grafted surface is typically significantly different from that of solution, which results in surface polarization (SP) effect with a jump of electric field. It is thus important to study how SP alters the PEB's structure and properties. In this work, the SP effects on PEB structure was studied using a statistical thermodynamic theory. The free energy functional to describe SP effect was constructed by using the image-charge method. Meanwhile, the electrostatic potential was solved from a modified Poisson-Boltzmann equation taking the ion solvation effect into consideration. In the absence of SP, the thickness of PEB exhibited a continuous collapse transition when decreasing the solvent quality. In the presence of SP, the collapse became a jump-like transition. Free energy analysis showed that the long-range Coulombic interaction dominated the transition because of the enhanced counterion condensation in the presence of SP. The theory provides an effective tool to study SP effect on PEBs, and the results explain the underlying physics in PEB collapse transition. [ABSTRACT FROM AUTHOR]

The most successful and popular machine learning models of atomic-scale properties derive their transferability from a locality ansatz. The properties of a large molecule or a bulk material are written as a sum over contributions that depend on the configurations within finite atom-centered environments. The obvious downside of this approach is that it cannot capture nonlocal, nonadditive effects such as those arising due to long-range electrostatics or quantum interference. We propose a solution to this problem by introducing nonlocal representations of the system, which are remapped as feature vectors that are defined locally and are equivariant in O(3). We consider, in particular, one form that has the same asymptotic behavior as the electrostatic potential. We demonstrate that this framework can capture nonlocal, long-range physics by building a model for the electrostatic energy of randomly distributed point-charges, for the unrelaxed binding curves of charged organic molecular dimers, and for the electronic dielectric response of liquid water. By combining a representation of the system that is sensitive to long-range correlations with the transferability of an atom-centered additive model, this method outperforms current state-of-the-art machine-learning schemes and provides a conceptual framework to incorporate nonlocal physics into atomistic machine learning. [ABSTRACT FROM AUTHOR]

In order to suppress electric wear of current collecting materials such as a contact wire and a contact strip in an electric railway, it is necessary to estimate the relationship between current and melting volume at a contact loss point. In this paper, we focused on a molten bridge which is considered as the main factor of electric wear at the contact loss point. And we proposed the estimation method of melting volume of contact wire and contact strip; in which film resistance is considered by using the relationship between the electric potential and the temperature at the contact spot. From estimation results, it is found that the melting volume increases as current increases, and that it increases as a contact boundary factor decreases. In addition, the authors carried out wear tests and measure a melting depth, a melting radius, and a melting volume under two conditions of current. From wear test results, experimental values of melting volume of the contact wire were in the range where contact boundary factor α was estimated from 0.90 to 0.94.

A semiconductor p-n junction diode with heavy doping under consideration is kept in forward biased condition. These are oppositely propagating electron and hole currents. These two streams interact among themselves and result in recombination, which supplies additional energy to the system. Such thermal energy creates additional electrical fluctuations, which exists long after the interaction has taken place. We have carried out an analytical investigation with numerical techniques as well as carried out a simulation of the wave–wave interaction in semiconductor junction diodes. In terms of signal transmission and operation of semiconductor device, such a theoretical study is important. [ABSTRACT FROM AUTHOR]

Recent developments in non-Hermitian physics offer exciting opportunities for a broad range of basic research and engineering applications relevant to the antennas and propagation community. In this article, we offer a tutorial geared toward introducing the unusual electromagnetic phenomena emerging in non-Hermitian systems, with a particular emphasis the subclass of these systems that obey PT symmetry. We first discuss the basic features of ${\hat{P}}$ , ${\hat{T}}$ , and ${\hat{P}}{\hat{T}}$ operators applied to electromagnetic and quantum mechanical phenomena. We then discuss the exotic response of PT-symmetric electromagnetic structures and their opportunities, including the singularities, known as exceptional points (EPs), emerging in these systems and their unusual scattering response. We discuss applications, challenges, and potentials in classical and quantum domains. [ABSTRACT FROM AUTHOR]

The bioelectric conduction model plays a key role in bioelectromagnetism analysis, such as solving electromagnetic forward and inverse problems. This paper is aimed to develop an anisotropic subvoxel-smooth conduction model (ASCM) to characterize the electrical conductivity tensor jump across the tissue interface, which is derived based on the interfacial continuity condition with asymptotic analysis method. This conduction model is furthermore combined with finite volume method to improve the numerical accuracy for solving electromagnetic forward problem. The performance of ASCM for electrical potential analysis is verified by comparison with analytic solution. The method is also applied to investigate the effect of anisotropic conduction on EEG analysis in a realistic human head model. [ABSTRACT FROM AUTHOR]

When learning science, students must often make sense of complex and counterintuitive ideas. However, this process of sensemaking is difficult, and consequently students risk emerging from science courses with highly fragmented understandings. In this study, I examine the ways in which students create conceptual connections to resolve such difficulties and defragment their understandings. Using three intersecting theoretical frameworks—Knowledge in Pieces, sensemaking, and conceptual blends—I analyze a case study of two undergraduate physics students making sense of the concepts of voltage, electric potential, and electric potential energy. I show how the students move through the different stages of the sensemaking process and how a conceptual blend was constructed and productively applied to help them resolve their knowledge fragmentation. Based on this case, I argue that conceptual blends can serve as a cognitive mechanism for the sensemaking process. [ABSTRACT FROM AUTHOR]

Recently, a non-equilibrium thermodynamic approach has been developed in order to model the fundamental role of the membrane electric potential in the cell behaviour. A related new viewpoint is introduced, with a design of a photobiomodulation treatment in order to restore part of the visual field. Here, a first step in experimental evidence of the validity of the thermodynamic approach is developed. This result represents the starting point for future experimental improvements for light stimulation in order to improve the quality of life of the patients. The future possible therapy will be in addition to the pharmacological treatments. [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]

Consider a knot K in S 3 with charge uniformly distributed on it. From the standpoint of both physics and knot theory, it is natural to try to understand the critical points of the potential and their behavior. We show the number of critical points of the potential is at least 2 t (K) + 2 , where t (K) is the tunnel number, defined as the smallest number of arcs one must add to K such that its complement is a handlebody. The result is proven using Morse theory and stable manifold theory. [ABSTRACT FROM AUTHOR]

In this paper, the thermoelastic vibrations of a functionally graded thermo-piezoelectric rod of limited length are considered using the generalized theory of thermoelasticity. Both ends of the rod are fixed at zero voltage and are exposed to a movable axial heat source. Using the Laplace transform analysis, the problem was solved. The expressions for the displacements, temperature, stress, electric field and electric potential were obtained. To consider the influence of the properties of gradient materials, the moving heat source velocity and thermo-piezoelectric response, some comparisons were constructed for different distributions of the physical quantities. The non-homogeneity effect on the field variables is also discussed in some detail.

The aim of this article is to develop a risk management procedure, which could be applied to the magnet design process, for both superconducting and normal magnets at the Jefferson Laboratory (JLab). This procedure allowed us to identify the key risks at each of the critical phases of design and propose procedures, tests, and checks to mitigate each risk. In this article, we present a qualitative and quantitative risk management procedure commonly referred to a “failure modes and effects analysis.” As part of this procedure, we calculated a risk priority number (RPN) for each activity of the process, identified the most critical activities and proposed mitigation activities, which in turn resulted in a revised RPN. Another benefit of this procedure was the identification of appropriate “control and hold” points within the design process, which allowed one to review and approve a particular outcome before proceeding to the next sequential activity. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical approach to glaucoma, with the aim of improving the comprehension of the biophysical bases for new possible therapies. The approach is based on a non-equilibrium thermodynamic model. The results point to the fundamental role of the membrane's electric potential and of its relation with inflammation and ion fluxes. A new viewpoint is suggested to consider anti-inflammation and photobiomodulation as possible therapies for glaucoma. [ABSTRACT FROM AUTHOR]

The evaporation possibility of micro sized metallic particles during them passage through the region of a magnetized plasma with a Maxwellian velocity distribution with the electron temperature in the range Te=1...100eV at presence of an ion beam with the energy in the range εb=1...6keV is studied theoretically. The floating potential of a macroparticle is obtained using the OML theory, the effect of the electron temperature and the energy of the ion beam on its magnitude is studied. The equation of energy balance on the macroparticle surface is obtained, such energy exchange mechanisms as collisions of particles of an ion beam and plasma particles with the macroparticle, thermal radiation of the macroparticle, as well as cooling due to the evaporation of substance from the macroparticle surface are taken into account. The effect of the temperature of plasma electrons and the ion beam energy on the stationary temperature of the macroparticle is studied. It is shown that for the given plasma and ion beam parameters, the temperature of the copper macroparticle is below the boiling point so that the evaporation of the macroparticle occurs at temperatures below the boiling point. The dependences of the macroparticle evaporation time on the electron temperature and the energy of the ion beam have been obtained.

Barkhausen noise (BHN) is a voltage signal induced by a coil due to the discontinuous magnetization of ferromagnetic materials. The BHN voltage value is strongly correlated with the microstructure of such materials. In this paper, we propose a new model whereby the BHN voltage pulse width is proportional to the travel distance of the domain wall between pinning sites, and the constant of proportionality corresponds to the domain wall velocity. This correlation is examined using a model sample wherein cementite and copper precipitates as pinning sites for the domain wall were dispersed in ferrite. The test results show that the BHN voltage pulse width T and the precipitate spacing L had a proportional relationship, and that the constant of proportionality L/T grew concomitant with increases in the excitation field. The change rate of L/T with excitation field was 3.8 × 10-4 A-1 m2 sec-1, and corresponded well to the reported value that was the correlation coefficient between the domain wall velocity and the excitation field. This result demonstrates the validity of our model whereby the BHN voltage pulse is equal to the time required for the domain wall to jump over the pinning sites. [ABSTRACT FROM AUTHOR]

In this study, electrical characteristics of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate) (PEDOT:PSS)/ITO devices have been investigated. The current-voltage (I-V) characteristics of devices show hysteresis behavior, and the hysteresis is formally described by different voltage amplitudes for the sweep from negative to positive bias and the reverse direction. According to the experimental results, the author suggested that donorlike trap states within the PEDOT:PSS layer controlled carrier flow and resulted in hysteresis-type I-V characteristics of ITO/PEDOT:PSS/ITO devices. [ABSTRACT FROM AUTHOR]

Current oscillations and other abnormalities in the dark current-voltage characteristics of an aluminum/silicon-rich oxide (SRO)/silicon structure were observed at room temperature. The SRO layers in the devices were fabricated by low pressure chemical vapor deposition and postdeposition thermal annealing. The spikelike current oscillations and other abnormalities are interpreted by an alternative switching between the on and off states of the conduction paths through the Si nanocrystallites at proper biases. [ABSTRACT FROM AUTHOR]

We have studied current versus voltage characteristics of n-GaN/u-AlGaN/n-GaN double heterostructure devices under hydrostatic pressure up to 500 MPa. Devices were grown on c-plane sapphire substrates by organometallic vapor phase epitaxy using epitaxial layer overgrowth. The effect of AlGaN layer thickness and composition on the pressure sensitivity was investigated. For a fixed applied bias, we found that the current decreases approximately linearly in magnitude with increasing hydrostatic pressure over the range of voltages and pressures applied. The decrease in current magnitude can be attributed to piezoelectric effects and is consistent with model calculations. The polarization charge densities at the GaN/AlGaN interfaces change with hydrostatic pressure, which in turn modifies the internal potential barrier. Changes in the AlGaN layer thickness and composition also modify the interfacial polarization, with thicker AlGaN layers and higher AlN content increasing the effect of pressure on the observed current versus voltage characteristics. The strain gauge factors obtained for these devices range from ∼200 to 800. [ABSTRACT FROM AUTHOR]

Electrically tunable solidly mounted thin film bulk acoustic resonators based on Ba0.25Sr0.75TiO3 and BaTiO3 films are fabricated and measured in wide dc bias voltage and temperature ranges. At room temperature, the tunability of the series and parallel resonances for the Ba0.25Sr0.75TiO3 resonator are 1.7% and 0.3%, respectively, for 15 V bias voltage applied over the 350 nm thick ferroelectric film (43 V/μm). The electromechanical coupling coefficient increases with dc bias up to 3.7% at 15 V. The measured tunability and coupling coefficient are limited partly by the quality of the used films. Potentially, they may be substantially increased for high quality films allowing application of higher dc fields. The resonator quality factor is approximately 100. The measured resonator response is in good agreement with available models based on the electromechanical equations describing the ferroelectric film under applied dc and ac electric fields. Measurements of the resonance frequencies of the Ba0.25Sr0.75TiO3 resonator as a function of temperature in the range 40–520 K reveal a sharp step at 150 K which is related to a structural phase transition of the ferroelectric material. The series resonance frequency is tuned to lower frequencies with increasing dc bias for all temperatures, while the parallel resonance frequency reveals a change in the sign of the tunability at approximately 150 K, from being tuned to lower frequencies at high temperatures to being tuned to higher frequencies at low temperatures. Measurements of BaTiO3 resonators in the temperature range 300–520 K are presented and compared to the Ba0.25Sr0.75TiO3 results. [ABSTRACT FROM AUTHOR]

Surface defect passivation for ZnO nanocombs (NCBs), random nanowires (RNWs), and aligned nanowires (ANWs) was performed through a metal plasma immersion ion implantation with low bias voltages ranging from 0 to 10 kV, where Ni was used as the modification ion. The depth of surface-originated green band (GB) emission is thus probed, revealing the surface origin of the GB. It is also found that the GB is closely related to oxygen gas content during growth of the nanostructures. The GB origin of NCBs and RNWs grown with higher oxygen content is shallower (∼0.5 nm), which can be completely quenched with no bias applied. However, the GB origin of ANWs grown at lower oxygen content is much deeper (∼7 nm) with a complete quenching bias of 10 kV. Quenching of the GB can be attributed to passivation of the surface hole or electron trapping sites (oxygen vacancies) by Ni ions. [ABSTRACT FROM AUTHOR]

In the present work an experimental investigation on the electrohydrodynamic (EHD) interaction effect, induced by means of a dielectric barrier discharge on a 1 atm subsonic air flow, is described. The air flow is obtained in an open circuit blowing wind tunnel at different air speeds. A plane plasma panel equipped with a dielectric discharge barrier system is immersed in the flow. A single phase sinusoidal power supply system, a superposition of a single phase sinusoidal system with a dc voltage supply, and a three phase symmetrical power supply configuration are considered. Electric, fluid dynamic, and spectroscopic diagnostic techniques are utilized. Pitot probe measurements are performed in the boundary layer on the plasma panel surface. Schlieren imaging is done to visualize the plasma sheath. Vibrational and rotational temperatures are evaluated by means of spectroscopic techniques. The force induced on the flow by the dielectric barrier discharge acts on the ions of the non-neutral sheath ahead of the plasma filament when travelling on the panel surface only. This causes a reduction of the time interval during which the force is active. The EHD effect and the momentum transfer to the gas flow in the boundary layer are reduced when the flow speed grows. An increase of the supply frequency and of the supply voltage causes an increase of the momentum transfer. In these experiments no significant increase of the efficiency of EHD effect is observed when utilizing the superposition of a dc voltage to a single phase power supply or a three phase power supply. [ABSTRACT FROM AUTHOR]

The electrical characteristics of low-energy (3 keV) Ge-implanted and, subsequently, thermal annealed SiO2 layers are investigated through capacitance-voltage (C-V) and conductance-voltage (G-V) measurements of metal-oxide-semiconductor capacitors. Particular emphasis is placed on the properties of such gate oxides for memory applications. Capacitance measurements at flatband voltage before and after the application of constant voltage stress in the accumulation regime indicate that the charge trapping behavior of the devices undergoes a major change after annealing at temperatures higher than 910 °C. The latter change is identified as a relocation of Ge atoms mainly toward the upper portion of the oxide with a significant fraction of them leaving the oxide; a finding in harmony with secondary ion mass spectroscopy analysis. The interface trap density (Dit) for the thin (9–12 nm) implanted oxides decreases with increasing annealing temperature, approaching at 950 °C the Dit levels in the mid-1010 eV-1 cm-2 range of the nonimplanted samples. At elevated annealing temperatures (>1000 °C), the device C-V characteristics are substantially disturbed. In this case, the presence of electrically active Ge atoms at an extended depth in the substrate modifies the intrinsic electrical properties of the n-Si substrate, lending a p-type conductivity character to the device high-frequency C-V curves. Substrate electrical modification is interpreted through a model that takes into account the formation of a SiO2/Ge-rich-Si/n-Si system. The SiO2/Ge-rich-Si interface presents very low Dit levels as revealed by conductance loss characteristics. The present study suggests that a combination of Ge implantation into SiO2 films and thermal annealing may be exploited in damage-free SiGe epitaxial growth technology based on Ge implantation. [ABSTRACT FROM AUTHOR]

The electronic structure of Cu(111)/pentacene and Ag(111)/pentacene interfaces were investigated with photoelectron spectroscopy and the hole barrier heights were determined to be 0.74 and 0.90 eV, respectively. When combined with previous measurements of the Au(111)/pentacene interface, the slope of the plot of metal work function against barrier height for Schottky barrier formation was determined to be 0.36, in agreement with current-voltage (I-V) measurements in the literature. However, the absolute barrier heights from photoemission measurements are 0.16 eV higher. The offset between the I-V measurement and the x-ray and ultraviolet photoelectron spectroscopy measurements was attributed to differences in how the highest occupied molecular orbital position is determined. Photoemission data indicates that at low coverages the pentacene molecules lie flat on the metal substrates, whereas at higher coverages the molecular orientation changes to orient the long molecular axis normal to the surface. Thicker films then tend to form three-dimensional islands, resulting in structured rather than flat films forming on clean Ag(111) and Cu(111) at room temperature. [ABSTRACT FROM AUTHOR]

We report results of thermal poling experiments performed with continuous and alternating electric fields in Suprasil glass. Firstly, the second-order nonlinearity induced with a continuous voltage is fully characterized, and the nonlinear region is found to extend to almost 80 μm under the anode surface. Then, we focus our study on experiments realized with a square alternating poling field. For particular frequencies in the millihertz regime, we found a 30 times increase of the generated second harmonic signal. The nonlinear layer created under these conditions is completely characterized and a χ(2) value of 0.3 pm/V is reached for the first time in a Suprasil glass. This χ(2) coefficient is one order of magnitude greater than best results reported so far in Suprasil glasses. [ABSTRACT FROM AUTHOR]

The emission characteristics and external quantum efficiencies of ambipolar polymer light-emitting field-effect transistors are investigated as a function of applied voltage, current density, and ratio of hole to electron mobility. Green-emitting poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) (F8BT) with balanced electron and hole mobilities and red-emitting poly((9,9-dioctylfluorene)-2,7- diyl-alt-[4,7-bis(3-hexylthien-5-yl)-2,1,3-benzothiadiazole]-2′,2″-diyl) (F8TBT) with strongly unbalanced hole and electron mobilities as semiconducting and emissive polymers are compared. The current-voltage and light output characteristics of the two types of light-emitting transistors were found to be fundamentally alike independent of mobility ratio. Device modeling allowing for a single (Langevin-type) charge recombination mechanism was able to reproduce the device characteristics for both cases but could not replicate the experimentally observed dependence of external quantum efficiency on current density. The increase of quantum efficiency with current density up to a saturation value could be indicative of a trap-assisted nonradiative decay mechanism at the semiconductor-dielectric interface. Optical output modeling confirmed that the maximum external quantum efficiency of F8BT light-emitting transistors of 0.8% is consistent with complete recombination of all charges and a singlet exciton fraction of 25%. [ABSTRACT FROM AUTHOR]

In this work, we investigate the combined influence of electromagnetic and acoustic Casimir forces on the pull-in voltage of microswitches with self-affine rough plates. It is shown that for plate separations within the micron range the acoustic term arising from pressure fluctuations can influence significantly the pull-in potential in a manner that depends on the particular roughness characteristics. Indeed, the acoustic term contribution can be comparable to that of surface roughness. Moreover, the temperature influence from the acoustic term appears to play a significant role besides that arising from the temperature dependence of the electromagnetic force due to quantum vacuum fluctuations. [ABSTRACT FROM AUTHOR]

The response of a ballistic mesoscopic Hall bar to a local potential barrier is investigated in the presence of an external magnetic field. The effect of the position of the local potential probe in the Hall cross on the Hall and bend resistance is investigated leading to two-dimensional (2D) resistance maps. The Onsager–Casimir symmetry relations and symmetry relations between resistance measurements when interchanging the current and voltage leads, is obtained numerically for such 2D resistance maps. Symmetry properties are derived for the Hall and bend resistance maps with respect to the position of the local potential barrier. [ABSTRACT FROM AUTHOR]

We report the growth behavior of oxide nanostructures according to physical properties such as work function, electrical and thermal conductivities, and roughness for high resolution nanostructure fabrication. Among these factors, threshold voltages, in particular, which induced the formation of a water meniscus and driving voltage, which drive oxyanions for oxidation, decreased as the mobility of electrons increased by the increasing electrical conductivity. Oxide growth increased as the diffusion of OH radical increased by the increasing conductivity of thermal energy. The high electrical and thermal conductivities imply that the reaction of the OH radical and surface was more easily activated over a wide reaction region (in the parallel direction of substrate) by the conductivity of the generated thermal energy at a low driving voltage. On the basis of these conductivity effects, the Cr film, which is the most sensitive to electron transport and conductivities, had hill-shaped nanostructures and could be applied as a candidate for high-speed atomic force microscope lithography at the lowest driving voltage. In addition, Ta and Ti, which are less sensitive, can be used to fabricate nanostructures with a high aspect ratio (spike shape). [ABSTRACT FROM AUTHOR]

A fundamental challenge in neuroscience is to understand what structure in the world is represented in spatially distributed patterns of neural activity from multiple single-trial measurements. This is often accomplished by learning a simple, linear transformations between neural features and features of the sensory stimuli or motor task. While successful in some early sensory processing areas, linear mappings are unlikely to be ideal tools for elucidating nonlinear, hierarchical representations of higher-order brain areas during complex tasks, such as the production of speech by humans. Here, we apply deep networks to predict produced speech syllables from a dataset of high gamma cortical surface electric potentials recorded from human sensorimotor cortex. We find that deep networks had higher decoding prediction accuracy compared to baseline models. Having established that deep networks extract more task relevant information from neural data sets relative to linear models (i.e., higher predictive accuracy), we next sought to demonstrate their utility as a data analysis tool for neuroscience. We first show that deep network’s confusions revealed hierarchical latent structure in the neural data, which recapitulated the underlying articulatory nature of speech motor control. We next broadened the frequency features beyond high-gamma and identified a novel high-gamma-to-beta coupling during speech production. Finally, we used deep networks to compare task-relevant information in different neural frequency bands, and found that the high-gamma band contains the vast majority of information relevant for the speech prediction task, with little-to-no additional contribution from lower-frequency amplitudes. Together, these results demonstrate the utility of deep networks as a data analysis tool for basic and applied neuroscience. [ABSTRACT FROM AUTHOR]

China’s transport sector is facing enormous challenges from soaring energy consumption and greenhouse gas (GHG) emissions. Transport electrification has been viewed as a major solution to transportation decarbonization, and electric vehicles (EVs) have attracted considerable attention from policymakers. This paper analyzes the effects of the introduction of EVs in China. A system dynamics model is developed and applied to assess the energy-saving and emission-reducing impacts of the projected penetration of EVs until the year 2030. Five types of scenarios of various EV penetration rates, electricity generation mixes, and the speed of technological improvement are discussed. Results confirm that reductions in transport GHG emissions and gasoline and diesel consumption by 3.0%–16.2%, 4.4%–16.1%, and 15.8%–34.3%, respectively, will be achieved by 2030 under China’s projected EV penetration scenarios. Results also confirm that if EV penetration is accompanied by decarbonized electricity generation, that is, the use of 55% coal by 2030, then total transport GHG emissions will be further reduced by 0.8%–4.4%. Moreover, further reductions of GHG emissions of up to 5.6% could be achieved through technological improvement. The promotion of EVs could substantially affect the reduction of transport GHG emissions in China, despite the uncertainty of the influence intensity, which is dependent on the penetration rate of EVs, the decarbonization of the power sector, and the technological improvement efficiency of EVs and internal combustion engine vehicles. [ABSTRACT FROM AUTHOR]

Detailed physics of the third quadrant electrical characteristics of 1.2-kV rated 4H-SiC accumulation (Acc) and inversion (Inv) channel MOSFETs, based on experimentally measured data and TCAD numerical simulations, are described in this paper for the first time. The power MOSFETs with various channel lengths (0.3, 0.5, 0.8, 1.1 $\mu \text{m}$) used in this paper were fabricated in a 6-in commercial foundry. Numerical simulations verified that there are two current paths in the third quadrant: 1) through the base region and 2) through the p-n body diode. This paper demonstrates that the Acc MOSFETs have a smaller third quadrant knee voltage (${V}_{{\text {knee}}})$ of −1.2 V compared with −1.9 V for the Inv MOSFETs (at ${V}_{g} = {0}$ V and room temperature). Numerical simulations show that this difference is due to a smaller potential barrier for electron transport from the drain to the source in the base region for accumulation channel devices than inversion channel devices. Acc devices are shown to have a lower voltage drop in the third quadrant. [ABSTRACT FROM AUTHOR]

The switching physics of ferroelectric, series capacitance theory and Pao and Sah's double integral are used for describing the polarization-voltage (P-V) characteristic of ferroelectric layer, capacitance-voltage (C-V) characteristic of MFMIS capacitor, and drain current-gate voltage (ID-VGS) and drain current-drain voltage (ID-VDS) characteristics of MFMIS FET. The effects of the area ratio on the P-V, C-V, ID-VGS, and ID-VDS characteristics are discussed. The results indicate that with the increase of the area ratio, the P-V characteristic, memory windows of C-V and ID-VGS characteristics become saturated, while the drain current ON/OFF ratio and applied voltage for saturated memory window decrease. [ABSTRACT FROM AUTHOR]

This study presents a modelling framework in which information on muscle fiber direction and orientation during contraction is derived from diffusion tensor imaging (DTI) and incorporated in a computational model of the surface electromyographic (EMG) signal. The proposed model makes use of the principle of reciprocity to simultaneously calculate the electric potentials produced at the recording electrode by charges distributed along an arbitrary number of muscle fibers within the muscle, allowing for a computationally efficient evaluation of extracellular motor unit action potentials. The approach is applied to the complex architecture of the first dorsal interosseous (FDI) muscle of the hand to simulate EMG during index finger flexion and abduction. Using diffusion tensor imaging methods, the results show how muscle fiber orientation and curvature in this intrinsic hand muscle change during flexion and abduction. Incorporation of anatomically accurate muscle architecture and other hand tissue morphologies enable the model to capture variations in extracellular action potential waveform shape across the motor unit population and to predict experimentally observed differences in EMG signal features when switching from index finger abduction to flexion. The simulation results illustrate how structural and electrical properties of the tissues comprising the volume conductor, in combination with fiber direction and curvature, shape the detected action potentials. Using the model, the relative contribution of motor units of different sizes located throughout the muscle under both conditions is examined, yielding a prediction of the detection profile of the surface EMG electrode array over the muscle cross-section. [ABSTRACT FROM AUTHOR]

Linear and nonlinear properties of obliquely propagating waves are studied in a degenerate dense cold magnetoplasma, comprising of Thomas–Fermi distributed electrons and ions as well as non-degenerate negatively charged dust particulates. By using the plane wave approximation, a linear dispersion relation for the dust-cyclotron (DC) and dust-acoustic (DA) waves is derived and analyzed numerically. For fully nonlinear waves, a Sagdeev pseudopotential theory is employed to derive an energy-balance equation and the soliton existence domain depending upon the dust concentration $(h)$ , obliqueness $(L_{z})$ , and Mach number $(M)$. Numerical analysis reveals that the parameter $h$ enhances the domain for allowed Mach numbers, i.e., $M_{1} < M < M_{2}$ and therefore favoring the solitary excitations, where $M_{1}$ and $M_{2}$ are the lower and upper Mach numbers, respectively. In addition, the dust concentration significantly reduces the amplitude and the profile sharpness of the solitary pulses. Similarly, variations in the obliqueness parameter and the Mach numbers modify the wave characteristics. This paper is important for understanding the nonlinear properties of electrostatic excitations in degenerate dusty magnetoplasma, relevant to white dwarfs (WDs), namely $GD56,\,\,GD29-38,\,\,GD362$ , and $WD2115-560$ , being termed as the DUSTY DAZ WDs. [ABSTRACT FROM AUTHOR]

Radiation-induced single event transients (SETs) are expected to evolve to single event multiple transients (SEMTs) due to the downscaling of transistor feature size, which also increases the difficulty of the vulnerability estimation for large-scale digital integrated circuits. In this paper, a novel layout-based soft error vulnerability estimation approach which is termed LBSEVEA is proposed to evaluate the impact of heavy ions on the vulnerability of combinational circuits. The physical process of interaction between particles and devices, especially nuclear reaction and scattering process are included in the LBSEVEA. In addition, ambipolar diffusion and bipolar amplification effect, which induce additional charge collection of the adjacent transistors and the hitting transistor, are also considered. A new method calculating the collected charge induced by the bipolar amplification effect is presented. By introducing the layout information of the target circuits into the identification of the adjacent cells, SEMTs effect can be considered in the vulnerability estimation. A fast SPICE simulation tool is adopted to conduct the fault injected netlist simulations, which can make a favorable compromise between the consumption of computer resources and simulation precision. Furthermore, induced soft error numbers, distributions of charge collected by the hitting nodes and the adjacent nodes, and SET pulse width distributions are presented. Besides, heatmaps of induced pulse widths for the layout of two benchmark circuits are provided. Finally, the constraints, the flexibility, and the scalability of the LBSEVEA are discussed. The ability to estimate the impact of process variations on the vulnerability is also presented. Compared with simulation and experimental results, the LBSEVEA can fairly estimate the vulnerability of combinational circuits. [ABSTRACT FROM AUTHOR]

The uniform gas discharge has long been pursued for realizing or improving some practical applications but is difficult to achieve due to the fact that nonuniform discharges are much easier to be generated in most cases. Usually, achieving uniform gas discharge requires sophisticated devices, and the operation is complicated and time-consuming. In this paper, we introduce simple and flexible multimethods for realizing uniform discharge from patterned structures under dielectric-barrier discharge (DBD) systems by varying experimental controlling parameters, and these methods can be employed in combination. The effects of driving frequency, voltage, duty ratio, and magnetic/electric field on glow DBD structure are investigated. It is found that a uniform glow DBD is obtained when frequency, voltage, and duty ratio are either very high or very low and also by the introduction of strong magnetic/electric field. The underlying physics of these methods is consistent as the elimination of a focusing effect of space electrons. It is concluded that the key of achieving uniform discharge is to uniformize the distribution of space charges. [ABSTRACT FROM AUTHOR]

The self-consistent leader inception and propagation model is used to analyze the influence of the phase voltage on the attachment of lightning to ultra-high voltage power transmission lines (UHV-TLs). An UHV-ac line with shielding failures reported in the literature is used as a case study. It is shown that the length of upward leaders initiated from conductors and their striking distances are longer under positive voltages than when energized with the opposite polarity. Therefore, the fraction of shielding failures of each conductor changes significantly with the phase angle in ac lines. However, it is found that the overall effect of voltage on lightning attachment can also be limited by the electrostatic screening produced by shield wires and their leaders. This proximity effect mainly reduces the velocity of upward leaders launched from energized conductors. Therefore, the effect of voltage on the lightning attachment process cannot be generalized since it is strongly coupled to the proximity of shield wires and their associated leaders. Thus, the lightning shielding performance should consider case-to-case variations in the upward leader velocity in different UHV-TLs designs, given not only by the line voltage but also coupled to the proximity of other wires and their launched leaders. [ABSTRACT FROM AUTHOR]

One of the pathological site effects in excitotoxic activation is Zn2+ overload to postsynaptic neurons. Such an effect is considered to be equivalent to the glutamate component of excitotoxicity. Excessive uptake of Zn2+ by active voltage-dependent transport systems in these neurons may lead to significant neurotoxicity. The aim of this study was to investigate whether and which antagonists of the voltage gated calcium channels (VGCC) might modify this Zn2+-induced neurotoxicity in neuronal cells. Our data demonstrates that depolarized SN56 neuronal cells may take up large amounts of Zn2+ and store these in cytoplasmic and mitochondrial sub-fractions. The mitochondrial Zn2+ excess suppressed pyruvate uptake and oxidation. Such suppression was caused by inhibition of pyruvate dehydrogenase complex, aconitase and NADP-isocitrate dehydrogenase activities, resulting in the yielding of acetyl-CoA and ATP shortages. Moreover, incoming Zn2+ increased both oxidized glutathione and malondialdehyde levels, known parameters of oxidative stress. In depolarized SN56 cells, nifedipine treatment (L-type VGCC antagonist) reduced Zn2+ uptake and oxidative stress. The treatment applied prevented the activities of PDHC, aconitase and NADP-IDH enzymes, and also yielded the maintenance of acetyl-CoA and ATP levels. Apart from suppression of oxidative stress, N- and P/Q-type VGCCs presented a similar, but weaker protective influence. In conclusion, our data shows that in the course of excitotoxity, impairment to calcium homeostasis is tightly linked with an excessive neuronal Zn2+ uptake. Hence, the VGCCs types L, N and P/Q share responsibility for neuronal Zn2+ overload followed by significant energy-dependent neurotoxicity. Moreover, Zn2+ affects the target tricarboxylic acid cycle enzymes, yields acetyl-CoA and energy deficits as well. [ABSTRACT FROM AUTHOR]

Adenosine deaminase (ADA) catalyzes the deamination of adenosine, which is important in purine metabolism. ADA is ubiquitous to almost all human tissues, and ADA abnormalities have been reported in various diseases, including rheumatoid arthritis. ADA can be divided into two conformations based on the inhibitor that it binds to: open and closed forms. Here, we chose three ligands, namely, FR117016 (FR0), FR221647 (FR2) (open form), and HDPR (PRH, closed form), to investigate the inhibition mechanism of ADA and its effect on ADA through molecular dynamics simulations. In open forms, Egap and electrostatic potential (ESP) indicated that electron transfer might occur more easily in FR0 than in FR2. Binding free energy and hydrogen bond occupation revealed that the ADA-FR0 complex had a more stable structure than ADA-FR2. The probability of residues Pro159 to Lys171 of ADA-FR0 and ADA-FR2 to form a helix moderately increased compared with that in nonligated ADA. In comparison with FR0 and FR2 PRH could maintain ADA in a closed form to inhibit the function of ADA. The α7 helix (residues Thr57 to Ala73) of ADA in the closed form was mostly unfastened because of the effect of PRH. The number of H bonds and the relative superiority of the binding free energy indicated that the binding strength of PRH to ADA was significantly lower than that of an open inhibitor, thereby supporting the comparison of the inhibitory activities of the three ligands. Alanine scanning results showed that His17, Gly184, Asp295, and Asp296 exerted the greatest effects on protein energy, suggesting that they played crucial roles in binding to inhibitors. This study served as a theoretical basis for the development of new ADA inhibitors. [ABSTRACT FROM AUTHOR]

Keyhole-mode plasma arc welding (PAW) has a good prospect in the manufacturing industry. Unified models of plasma arc and workpiece help to reveal the physical mechanism in PAW for a better application. Previous unified models either deal with a constant keyhole situation or take too much computational time to display the dynamic keyhole process with a two-phase flow method. In view of the convenience for industrial application as well as good accuracy, a convenient unified model was developed to describe the mobile keyhole-mode PAW. With a simplified technique, the multiphase heat and force effect between plasma arc and workpiece was turned into a single-phase problem at each individual domain. Thus, it takes less computational time than previous unified models. The temperature field and weld pool during the mobile keyhole-mode PAW process were revealed, the arc flow and pool flow were displayed and the electric potential was predicted. The experiment was conducted on a stainless-steel plate, and the weld pool image and the measured arc pressure agree well with the calculated result. The calculated electric potential drop also coincides with the experiment. The model provides a convenient and accurate method to display the mobile keyhole-mode arc welding process.