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In this study, the space charge in oil-impregnated thick pressboard and Kraft paper were measured by the pulsed electroacoustic (PEA) method from -20 to +60 °C. A bipolar charge transport model was used to simulate the transport processes of homocharge and heterocharge, and the acoustic attenuation process in the samples. The test results show that space charge accumulates in the thick pressboard and Kraft paper increases first and then decreases with temperature, and its maximum appears at 40°C, while little space charge accumulates at -20°C. The space charge near the lower electrode shrinks in the oil-impregnated thick pressboard at high temperature and the shrinkage is larger at 60°C. In the oil-impregnated Kraft paper, the accumulation and charge density of positive charge is different from negative charge. The ion transport process model simulates the charge shrinkage near the electrode, and disappears at the upper electrode after the acoustic attenuation simulation. The model established in this paper can well simulate the space charge distribution of oil-impregnated thick pressboard and Kraft paper under different temperatures. [ABSTRACT FROM AUTHOR]

In this work, samples of oil-immersed paper with different moisture levels and aging condition were studied. Frequency domain spectroscopy (FDS) of the samples was examined at 40 °C under different excitation voltages. A non-linear phenomenon in frequency domain dielectric response with different moisture contents and aging condition was observed. The non-linear phenomenon appears to be related to the hindrance effect of cellulose on the movement of ions and the Poole-Frenkel effect on the concentration of ions. With aging, the nonlinear loss peaks at different frequencies caused by the effect of nonlinear conductance and interface polarization appear in the FDS results. The non-linear phenomenon was modeled and verified experimentally. The characteristic parameters and quantitative method to estimate moisture content and the degree of aging degree of oil-immersed paper can be obtained by the proposed method. [ABSTRACT FROM AUTHOR]

Activation energy is popularly used for the estimation of remaining life of transformer insulation. It is defined as the average rate of all reactions that happen with cellulose. Existing literature shows that the activation energy of oil–paper insulation can be obtained from polarization depolarization current (PDC) and return voltage measurement (RVM) data that are measured at a specific temperature. It is practically difficult to ensure the same measurement temperature for both PDC and RVM data. On the other hand, PDC data and its analysis get influenced by de-trapping current. This de-trapping current is generated by ionic charge carriers that get freed from trap sites during PDC measurement process. Formation of these trap sites is related to physical, chemical reactions that happen at oil–paper interface. This paper proposes a methodology which uses de-trapped charge, dislodged from deep and shallow traps, to assess insulation condition and for the prediction of activation energy. Thus, eliminating the need of RVM data. The proposed method is tested using data collected from various real-life in-service transformers. [ABSTRACT FROM AUTHOR]

This paper introduces a possible mechanism to explain the changes in neurons following extremely low frequency magnetic fields (ELF-MFs). The model in this paper contains two parts: the physical part and the bio-trigger part. The first part is an electric current equation, which is a generalization of the Nernst–Plank equation with the exposure of ELF-MF, and the second bio-part is a phenomenological model, which is a simple two-state channel with two steady state open (O) state and closed state (C). The two parts are complementary. The first part is utilized to explain changes about synaptic plasticity following ELF-MF exposure at embryonic and postnatal age. The second part is used to simulate the process of three different types of neurons reported by previous papers. According to the results, the present model is feasible for the simulation process. The concept of ion mobility or permeability is emphasized in this paper in part I, and channel state transition probabilities are paid much attention to in part II. In this paper, the ion mobility or permeability is supposed to have close relationships with ion channel transition probabilities, which connects the two parts of the model together. [ABSTRACT FROM PUBLISHER]

Conventionally, integrated drain-extended MOS (DeMOS) like high-voltage devices are designed while keeping only performance targets for a given application in mind. In this paper, for the first time, performance and reliability codesign approach using 3-D TCAD has been presented for various superjunction (SJ) type DeMOS devices. In this context, how to effectively utilize the SJ concept in a DeMOS device for System on Chip applications, which often has stringent switching and RF performance targets, is explored in detail in this paper. Moreover, design and reliability tradeoffs for switching and RF applications are discussed, while considering two unique sets, one with fixed breakdown voltage and other with fixed ON-resistance. Finally, hot carrier generation, safe operating area concerns, and electrostatic discharge physics are explored and compared using 3-D TCAD simulations. [ABSTRACT FROM PUBLISHER]

A novel plasma Charge Accumulative Model (pCAM) by calculating time-integrated Fowler–Nordheim (FN) tunneling charges and field of the gate dielectric in plasma processes is proposed in this paper. Our prior studies have developed and presented a quantitative FinFET plasma recording device by an effective fin-shaped field effect transistor (FinFET) contact-to-metal coupling structure to record and quantify plasma ion charges created in FinFET backend processes. In this paper, a precise analytical model is proposed to model the magnitude of plasma ion charges, time-integrated stressing field, and the criteria of the plasma process for optimum FinFET process technology. The new pCAM is highly matching with the measurement result of 16- and 7-nm FinFET wafers. The model can be adapted to practically estimate the plasma damage with different charge types, process parameters, and ion distribution; it can optimize the FinFET process and further understand the plasma damage mechanism in charging processes of 7-nm FinFET and beyond. [ABSTRACT FROM AUTHOR]

In this paper, a complete flux scheme (CFS) has been implemented in 1-D fluid model for simulating the pulsed dielectric barrier discharge (DBD) in pure argon at atmospheric pressure. The characteristic quantities of the pulsed DBD have been systematically calculated by using the CFS and presented in comparison with those by using the exponential difference scheme (EDS). This paper shows the following results. There is the two-pulse discharge mode in the present simulation. The two discharge currents obtained using the CFS and EDS converge to the same result in good agreement with the experiment as spatial step length decreases, but the CFS has a fast convergence performance compared to the EDS. With a small grid number, the numerical scheme has an evident effect on the characteristic quantities in the time region corresponding to the first discharge pulse. This paper suggests that in the pulsed DBD, the usage of the CFS with a properly small grid number can give more accurate result and also presents a high calculation efficiency. [ABSTRACT FROM AUTHOR]

Basic kinetic process of plasmas is studied by a first principle based N-body simulation. By confirming Coulomb collisional relaxation process, this paper is extended to investigate the dynamics of Debye shielding. Some of the key numerical techniques are discussed, including how to avoid singularities at the near encounter of two charged particles. Electron distribution function in Debye shielding is revealed, which deviates from conventional Maxwellian distribution function. [ABSTRACT FROM AUTHOR]

In inertial confinement fusion, the scientific issues include the generation and transport of driver energy, the pellet design, the uniform target implosion physics, and the realistic nuclear fusion reactor design. In this paper, we present a pellet injection into a power reactor in heavy-ion inertial fusion (HIF). We employ a magnetic correction method to reduce the pellet alignment error in HIF reactor chamber, including the gravity, the reactor gas drag force, and the injection errors. We found that the magnetic correction device proposed in this paper is effective to construct a robust pellet injection system with a sufficiently small pellet alignment error. [ABSTRACT FROM AUTHOR]

The past measurements of the plasma density and potential profiles near the exit of the keeper electrode in a hollow cathode device suggested that turbulent ion acoustic fluctuations and ionization instability in the cathode plume significantly increased the energy of the ions that flow from this region. The lifetime of keeper electrode is limited by sputtering or ion bombardment of the Molybdenum surface exposed to the discharge plasma. Increases in the cathode gas flow reduce the amplitude of the fluctuations and the number and energy of the energetic ions, which decreases the erosion rate of the keeper electrodes. However, as the cathode gas flow is raised for a given discharge current, the performance of a 5-kW Annular-Geometry Ion Engine (AGI-Engine) declines. There is a strong relationship between the performance and the lifetime of the ion thruster. To validate whether the 20-A hollow cathode satisfied China’s communication satellite platform’s application requirement for North-South station keeping, this paper analyzed the effect of the cathode gas flow on the performance and the lifetime of the AGI-Engine. Different from the previous methods, this paper first tracked the movement of energetic ions generated in the plume of the hollow cathode, predicted erosion rates, found where they hit the keeper electrode, and then determined the amount of material that they sputtered. A review of past experimental results was presented first. Next, based on the existing experimental data, theoretical analysis and numerical calculations were performed to determine the optimum gas flow range and the performance curve of the 20-A hollow cathode. The results showed that the primary erosion mechanism of the keeper electrode was caused by impact from Charge Exchange Xenon (CEX) ions, which caused the cathode orifice to be widened and attenuated over time. However, heavy double xenon ($\text{X}_{\text{e}}^{++}$) ions, which struck the keeper electrode more severely than CEX ions, were the most crucial factor that limited the lifetime of the 20-A hollow cathode due to their high energy and large mass. [ABSTRACT FROM AUTHOR]

This paper presents the 2-D numerical simulation results of single-event burnout (SEB) in 4H-SiC junction barrier Schottky (JBS) diode by low carrier lifetime control (LCLC) for the first time. We investigate the SEB performance based on an 1800-V JBS structure and find that the most sensitive ion’s strike position is the middle of junction spacing because of the punchthrough of the electric field at anode contact. Then, the SEB hardening mechanism of LCLC is studied in this paper that the double-sided peak electric field can be effectively improved which results in a significantly decrease of maximal temperature. For the incident particle with different linear energy transfer values, we find that the SEB threshold voltage can be substantially enhanced when the carrier lifetime ($\tau $) is under a certain value. In addition, the basic characteristics with LCLC are discussed that the forward and reversed characteristics are hardly affected. [ABSTRACT FROM AUTHOR]

Bar-plate configuration has a vital function in the intensive study of corona discharge mechanism. To study the discharge characteristics of the steady current stage in this configuration, this paper proposes a hybrid numerical algorithm composed by the finite-element method and the finite-volume method. The former solves Poisson’s equation and calculates the value of onset field intensity. The latter solves the current continuity equation, in which a time-varying charge item is added. This charge item can increase the stability of the hybrid algorithm. This paper also proposes a new selection strategy for the initial charge and inception voltage on the bar electrode surface. Based on this algorithm, corona current under different electrode radii, gap distances, and applied voltages was calculated. In this way, the distribution characteristics of an electric field intensity and space charge density along the whole gap in the model can be obtained through the experiment. To verify the validity of the algorithm, the related experiment is carried out in the laboratory. The simulation results have a good consistency with the experimental results, verifying the validity of the algorithm proposed in this paper. [ABSTRACT FROM AUTHOR]

Tunnel FETs (TFETs) have been identified as the most promising steep slope devices for ultralow power logic circuits. In this paper, we demonstrate in-plane InAs/Si TFETs monolithically integrated on Si, using our recently developed template-assisted selective epitaxy approach. These devices represent some of the most scaled TFETs with dimensions of less than 30 nm, combined with excellent aggregate performance with average subthreshold swing (SS), of around 70 mV/decade combined with I\mathrm{\scriptscriptstyle ON} of a few \mu \textA / \mu \textm for |V\mathrm {\mathbf {DS}}| = |V\mathrm {\mathbf {GS}}| = 0.5 V. Here, we will discuss the device fabrication as well as the experimental electrical data. Extensive low temperature characterization and activation energy analysis is used to gain insights into the factors limiting device performance. Combined with the simulation study presented in part 2 of this paper, this will elucidate how traps are ultimately limiting the SS. [ABSTRACT FROM AUTHOR]

An ion-flow field is very important for the design of an HVDC transmission line. Due to the space ions resulting from corona discharge, there are few practical methods to measure the space electric fields around HVDC transmission lines. In this paper, a compensation method is presented to measure the space potential in the ion-flow field. The space potential can be obtained by applying an adjustable voltage source to a suspended conductor, increasing the voltage step-by-step and measuring the current flowing through the voltage source or the ground-level ion current density under the suspended conductor. When the current is equal to zero or the ground-level ion current density is equal to that without the suspended conductor, the output voltage of the voltage source is the space potential to be measured. The paper first introduces the principle of the measurement method. Then, the feasibility of the method is testified on unipolar and bipolar reduced-scale models. Finally, the measured results are discussed and are compared with the results by the numerical method. [ABSTRACT FROM AUTHOR]

The Chinese Fusion Engineering Testing Reactor (CFETR) is a next fusion device proposed in China. The ability to exhaust the plasma power loss is a critical issue for the successful production of a fusion power reactor. For Phase II of CFETR with fusion power ~1 GW, the extremely large divertor heat load would be a severe challenge to achieve steady-state operation. In this paper, we have simulated the divertor performance by using SOLPS5.0 (B2.5-EIRENE) code package for a lower single null divertor configuration based on a core self-consistent steady-state scenario with Ar seeding. The core self-consistent steady-state scenario is calculated by a 1.5-D modeling workflow utilizing the One Modeling Framework for Integrated Tasks (OMFIT) framework. The modeling shows that Ar puffing from the lower divertor region together with D2 puffing from upstream is highly effective in mitigation of the divertor peak heat flux and temperature for the whole outer target and near strike point on the inner divertor target, however, electron and ion temperature ( $T_{e}$ and $T_{i})$ at far scrape-off layer on inner divertor is still higher than the erosion mitigation. In addition, comparison simulation of different divertor geometries has been performed in this paper. Further work on self-consistent core-edge coupling to estimate the effect of impurity seeding on core performance as well as the optimization of divertor geometry and operations will be studied. [ABSTRACT FROM AUTHOR]

This paper presents a self-consistent model of plasma polarization around an isolated micrometer-sized dust particle being under the action of an external electric field. It describes ion focusing and wake formation for dust particles with different radii and external electric fields. It is shown that despite the formation of wake, plasma maintains a quasi-neutral condition around a negatively charged dust particle, and the volume charge formed as a result screens the dust particle completely. It is also shown that in the external electric field, the dipole moment of the part of the ion nearest to the dust particle is proportional to the dust particle charge. As the external electric field increases and reaches some threshold value, a positive peak appears in plasma potential downstream of the dust particle. It then increases linearly and shows a broad maximum. [ABSTRACT FROM AUTHOR]

Melamine formaldehyde microspheres are widely used in dusty plasma experiments for their monodispersity, sphericity, low mass density, and well defined sizes. This paper summarizes problems that were encountered in numerous applications of these grains in different laboratory simulations. and the already published results are discussed in view of new experiments. The main results of this paper are connected with changes of the grain mass due to the decreased pressure and/or increased temperature and variations of the grain dimensions, its shape, and mass density under electron or ion bombardments. By contrast to the work function estimated from field emission properties, we have found the photoelectric work function (4.5 eV) being close to that expected. A sputtering of the grains using a 30-keV ion beam revealed their unexpected heterogeneity. [ABSTRACT FROM AUTHOR]

Space charge distribution is a valuable indicator of ion flow field and is widely utilized to assess electromagnetic environment for transmission line. The finite-element method (FEM) is widely used to solve this problem. However, Kaptzov assumption in FEM assumes that onset voltage is unchangeable after corona occurs, which does not tally with the actual situation. This paper adopted the finite-element iteration method (FEIM), which uses empirical formula instead of assumptions to calculate the charge density. The surface field intensity is not constant in the empirical formula because the empirical formula takes the effects of space charge on surface field into consideration. So this is more consistent with actual situation. In order to verify the accuracy of the algorithm, sound pulse method is applied to measure the charge density around the conductor in the laboratory. Simulation results show that the charge density obtained in this paper agrees with the data in the experiment, which verifies the validity of the empirical formula for calculation of space charge density. Compared with a method considering Kaptzov assumption, FEIM is closer to the experiment in area around conductor line and near the ground. This indicates that empirical formula in FEIM is more effective than Kaptzov assumption in these two domains. [ABSTRACT FROM AUTHOR]

The microwave plasma torch (MPT) is an attractive plasma source in both industry and scientific research because of its advantages in electrodeless operation ability, high energy efficiency, and flexibility under different operational conditions. However, relatively few numerical studies have been carried out for the MPT fed by a rectangular waveguide in two or even three dimensions. Therefore, this paper presents a 2-D, axisymmetric, and stationary fluid models to characterize the MPT, with an emphasis on the mechanism of the surface wave formation and the sustentation of the plasma column. Nine partial differential equations are included in this research, coupling microwave radiation, heat transfer, plasma bulk flow, and transport of different species with each other. The obtained results reveal how the traveling surface wave occurs and elucidate the consequent influence of the surface wave formation. Furthermore, this paper demonstrates the extension of the plasma column length and the propagation of the surface wave with an increase in the total plasma-absorbed microwave power. The dependence of the plasma column length on the plasma-absorbed microwave power is found to be motivated by the surface wave propagation. The limitations of the model and the difficulties in its numerical implementation are also discussed in the paper. [ABSTRACT FROM PUBLISHER]

This paper considers thermal neutralized charge electron flux moving through immovable static ion background. A 2-D dispersion equation is derived. The equation describes linear waves of space charge (WSC) in the flux. In the result of the dispersion equation analysis, we proved the existence of the backward and sideward WSCs. Maps on the plane $\{{k_{x}; k_{y}} \}$ were calculated and plotted for two values of the electrons drift velocity. The lines on those maps correspond to the direct, sideward, and backward WSCs. Areas of obtuse and acute drift angles are marked out. [ABSTRACT FROM AUTHOR]

Nowadays, online social networks, such as “Facebook” and “WeChat,” facilitate the expression, diffusion, and interactions of individuals’ opinions regarding various issues. In this environment, individuals’ opinions are liable to be influenced by others and then evolve over the time. In this paper, we propose an approach based on minimum adjustments to manage the consensus in the group decision making (GDM) with opinions evolution. First, inspired by the idea proposed in DeGroot model, we establish a novel GDM model with opinions evolution, and then discuss its consensus conditions. Based on this, we propose an algorithm to achieve the network partition, and then provide a consensus model with minimum adjustments to obtain the optimal adjusted initial opinions and collective consensus opinion. Finally, we provide a numerical example to demonstrate the feasibility and effectiveness of the proposed theoretical results, and design comparative simulations to explore the effects of the opinions evolution on the final consensus solution. [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]

The front plates and embedded particle sensor shells that are part of the electric field instrument (EFI) on the Swarm satellites have recently been used as planar Langmuir probes, as an additional diagnostic tool to infer environment parameters. The interpretation of measured currents in terms of the plasma density or incoming flow speed, however, requires a knowledge of the front plate effective cross section $A_{\textrm {eff}}$. Measurements made under various space plasma conditions have led to the conclusion that this cross section is generally larger than the known geometrical cross section $A_{\textrm {geo}}$. Interpretations of measurements have thus been made using fixed relative enhancements of $A_{\textrm {geo}}$ ranging from 8% to 17%. In this paper, results from kinetic simulations are presented, from which the effective cross section can be determined over a range of plasma parameters. These are used to shed light on the physical mechanisms responsible for this enhancement and construct an empirical fit to the relative enhancement $\delta $ , where $A_{\textrm {eff}} = A_{\textrm {geo}}(1 + \delta)$ , and, in turn, enable improvements in the accuracy of inferred plasma parameters. [ABSTRACT FROM AUTHOR]

In nuclear fusion reactors, unipolar arcing is a longstanding plasma surface interaction issue. In this paper, short summaries of morphology changes by helium plasma irradiation under fusion relevant conditions and ignition of arcing on the He irradiated surfaces are given. Helium plasma irradiation leads to surface morphology changes, and arcing can be ignited on the surface in response to pulsed heat load accompanied by plasma instabilities. Then, we focused on arcing ignited on large-scale fiberform nanostructures (LFNs) formed with deposition of metallic particles together with helium-ion irradiation. Dusts release from the arc spot and the amount of material erosion are discussed based on the experiments. [ABSTRACT FROM AUTHOR]

This paper is devoted to the further development of a numerical model for the simulation of high-current vacuum arcs (HCVA) with cathode attachment in the form of multiple cathode spots. The model allows one to simulate different modes of HCVA and the transition between them. It is shown that the secondary plasma, arising from the anodic sputtering and nonadherence of the incident ions, affects the constriction of the plasma and the transition between the HCVA modes. [ABSTRACT FROM AUTHOR]

In this paper, a charge plasma-based monolayer transition metal dichalcogenide (TMD) tunneling field-effect transistor (TFET) is investigated by solving self-consistent 3-D Poisson and Schrodinger equations in nonequilibrium Green’s function (NEGF) framework. We propose a work function engineered charge plasma-based dual-metal source TFET (DMS TFET) structure for an optimum performance of the device. The proposed TFET structure demonstrates superior performance than the conventional charge plasma TFETs in terms of ${I}_{{\scriptscriptstyle {\text {ON}}}}$ , ${I}_{{\scriptscriptstyle {\text {ON}}}}/{I}_{{\scriptscriptstyle {\text {OFF}}}}$ ratio, and subthreshold slope (SS). It provides ${I}_{{\scriptscriptstyle {\text {ON}}}}$ of $222~\mu \text{A}/\mu \text{m}$ , ${I}_{{\scriptscriptstyle {\text {ON}}}}/{I}_{ \mathrm{\scriptscriptstyle OFF}}$ ratio of $2.22\times 10^{{5}}$ , a minimum SS of 42.41 mV/decade, and an average SS of 54.15 mV/decade for three-decade increase in drain current (${I}_{\text {DS}}$). The performance of the device is observed at different channel lengths. Based on this analysis, a device design guideline for sub-10-nm channel length TFETs is presented in the paper. Finally, the circuit level metrics of the proposed structure are estimated by calculating delay and energy-delay product of a 45-stage inverter chain. [ABSTRACT FROM AUTHOR]

This paper presents the simulation-based comparison between silicon (Si) and silicon carbide (SiC) MOSFETs on the single-event burnout (SEB) performance for the first time. The safe operation areas (SOAs) regarding SEB are extracted and compared between the two structures when the heavy ions with a different linear energy transfer (LET) strike the sensitive areas of the devices. It is demonstrated that benefiting from the higher doped drift region, SiC MOSFET has a larger SEB threshold voltage than Si MOSFET at low LET range. However, it is the other way around at high LET range, which is attributed to the thicker epitaxy of Si MOSFET. The introduction of buffer layer to enhance the SEB hardness is also discussed. Results indicate that a thicker buffer layer is required for SiC MOSFET to enlarge the SOA, resulting in a more serious degradation of the specific ON-resistance (${R}_{ \mathrm{\scriptscriptstyle ON},\textsf {sp}}$). Consequently, other hardening solutions need to be further explored to ensure the safe operation of SiC MOSFET in space applications. [ABSTRACT FROM AUTHOR]

In the domain of printed electronics (PE), field-effect transistors (FETs) with an oxide semiconductor channel are very promising. In particular, the use of high gate-capacitance of the composite solid polymer electrolytes (CSPEs) as a gate-insulator ensures extremely low voltage requirements. Besides high gate capacitance, such CSPEs are proven to be easily printable, stable in air over wide temperature ranges, and possess high ion conductivity. These CSPEs can be sensitive to moisture, especially for high surface-to-volume ratio printed thin films. In this paper, we provide a comprehensive experimental study on the effect of humidity on CSPE-gated single transistors. At the circuit level, the performance of ring oscillators (ROs) has been compared for various humidity conditions. The experimental results of the electrolyte-gated FETs (EGFETs) demonstrate rather comparable currents between 30%–90% humidity levels. However, the shifted transistor parameters lead to a significant performance change of the RO frequency behavior. The study in this paper shows the need of an impermeable encapsulation for the CSPE-gated FETs to ensure identical performance at all humidity conditions. [ABSTRACT FROM AUTHOR]

Many terrestrial and astrophysical plasmas encompass very large dynamical ranges in space and time, which are not accessible by direct numerical simulations. Thus, idealized subvolumes are often used to study small-scale effects including the dynamics of magnetized turbulence. A significant aspect of magnetized turbulence is the transfer of energy from large to small scales, in part through the operation of a turbulent cascade. In this paper, we present a new shell-to-shell energy transfer analysis framework for understanding energy transfer within magnetized turbulence and in particular, through the cascade. We demonstrate the viability of this framework through application to a series of isothermal subsonic and supersonic simulations of compressible magnetized turbulence and utilize results from this analysis to establish a nonlinear benchmark for compressible magnetized turbulence in the subsonic regime. We further study how the autocorrelation time of the driving and its normalization systematically change properties of compressible magnetized turbulence. For example, we find that $\delta $ -in-time forcing with a constant energy injection leads to a steeper slope in kinetic energy spectrum and less efficient small-scale dynamo action. We examine how these results can impact a range of diagnostics relevant for a range of terrestrial and astrophysical applications. [ABSTRACT FROM AUTHOR]

This paper investigates the issues of oxygen accumulation and variation in the high-resistance state of HfO2-based resistive random access memory (RRAM), with improvement attained by inserting a thin oxygen-vacancy-rich layer of indium-tin-oxide (ITO) film. By acting as the oxygen ion reservoir, this ITO thin film on the TiN electrode can further stabilize resistance switching (RS) characteristics. In terms of reliability, ac endurance, and retention tests confirm stable RS characteristics for the Pt/HfO2/ITO/TiN device. Finally, a conducting model was proposed to explain the influence of the ITO thin layer and clarify the physical mechanism of electrical improvements. [ABSTRACT FROM AUTHOR]

This paper outlines the requirements for a source of buffer plasma, which is necessary for elaboration of plasma separation method of substances and following foundations development of plasma reprocessing technology of spent nuclear fuel and radioactive waste. Such source is implemented on the basis of a helicon discharge, allowing plasma generation in a cylindrical volume with characteristic dimensions on the order of 1 m and bounded by metal walls. At plasma-forming gas (argon) pressure of 1 mTorr, radial profiles of density $n_{e}$ and temperature $T_{e}$ of electrons were obtained for various magnetic field magnitudes (0–200 G) and RF power (up to 6 kW) using double probe and optical methods. The typical value of $T_{e}$ amounted to eV units and $n_{e}$ was about 1012 cm−3. [ABSTRACT FROM AUTHOR]

With the accessibility to information, users often face the problem of selecting one item (a product or a service) from a huge search space. This problem is known as information overload. Recommender systems (RSs) personalize content to a user’s interests to help them select the right item in information overload scenarios. Group RSs (GRSs) recommend items to a group of users. In GRSs, a recommendation is usually computed by a simple aggregation method for individual information. However, the aggregations are rigid and overlook certain group features, such as the relationships between the group members’ preferences. In this paper, it is proposed a GRS based on opinion dynamics that considers these relationships using a smart weights matrix to drive the process. In some groups, opinions do not agree, hence the weights matrix is modified to reach a consensus value. The impact of ensuring agreed recommendations is evaluated through a set of experiments. Additionally, a sensitivity analysis studies its behavior. Compared to existing group recommendation models and frameworks, the proposal based on opinion dynamics would have the following advantages: 1) flexible aggregation method; 2) member relationships; and 3) agreed recommendations. [ABSTRACT FROM AUTHOR]

In this paper, a new circuit model is proposed to simulate plasma-induced damage (PID). It includes the two sheaths of the plasma, the blocking capacitor, and the RF power source coupled with the victim device. As a result, this model accounts for both the ac behavior of the plasma and the local voltage imbalance induced by differences in shading factors. The advantage of this approach, compared with the previous works, is that it can yield the waveform impinged by the plasma on the transistor gate, which is known to influence the amount of reliability degradation experienced by the device. Finally, this model is also utilized to elucidate the impact of a parasitic capacitance connected to the transistor gate on the extent of the PID inflicted on the victim device. [ABSTRACT FROM AUTHOR]

Superconducting QUantum Interference Devices (SQUIDs) based on nanobridge junctions have shown increasing promise for single particle detection. This paper describes the development of the fabrication of improved and reproducible nanobridge junctions fabricated by focused ion beam (FIB) milling from niobium thin films. Although the very low noise properties of nanobridge SQUIDs are well known, the nature of the milling process is little understood at the level of local superconducting properties. In this paper, we report the results for nanobridge Josephson devices and SQUIDs, which we believe are the first to be made by Xenon (Xe) FIB milling. Temperature-dependent current–voltage behavior, microwave-induced Shapiro steps, and SQUID response to magnetic fields have been measured. We make preliminary comparisons with nominally identical devices milled from Nb thin films using either Xe or Ga ions. [ABSTRACT FROM AUTHOR]

The switching properties of Te and TeTiW top electrodes (TEs) on TiW/SiN/TiN resistive switching memory devices are explored in this paper. The TeTiW TE device exhibits more favorable bipolar resistive switching behavior because of the decrease in binding energy after its use. This finding is confirmed through X-ray photoelectron spectroscopy analyses. The filament of the TeTiW TE device is metal like after forming, and the reset process corresponds with the thermal-dissolution mechanism. A physical model based on a Te filament is constructed to explain such phenomena. The TeTiW TE device provides the excellent endurance of more than 104 cycles, with an ON/OFF ratio of 500. The improvement can be attributed to the filament’s robustness during the forming and set processes, which prevent its diffusion even at high temperature. The device also features long retention for up to 104 s at 225 °C without stress, and 104 s at 85 °C with stress of −0.3 V. Therefore, it has high potential for high-density nonvolatile memory applications. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate the linear conductance-change characteristics of a conductive-bridging RAM (CBRAM) to be employed as an artificial synapse device in neuromorphic systems. The CBRAM with a bilayer electrolyte structure (${\mathrm {Cu/Cu}}_{{2}-{x}}\text{S}$ / $\mathrm {WO}_{{3}-{x}}$ /W) exhibits analog switching behavior during the depression process due to the well-controlled dissolution of the conductive filament. To analyze the origin of this motion, we investigate the effective voltage applied to $\mathrm {Cu}_{{2}-{x}}\text{S}$ and $\mathrm {WO}_{{3}-{x}}$. Our findings reveal that $\mathrm {Cu}_{{2}-{x}}\text{S}$ , acting as a voltage divider, helps in suppressing the large voltage drop in $\mathrm {WO}_{{3}-{x}}$ , where the formation/dissolution of filament occurs. Furthermore, due to the diode-like characteristics of $\mathrm {Cu}_{{2}-{x}}\text{S}$ and the division of voltage drop between $\mathrm {WO}_{{3}-{x}}$ and $\mathrm {Cu}_{{2}-{x}}\text{S}$ , an optimum programming energy is applied to $\mathrm {WO}_{{3}-{x}}$ during the depression process. This leads to linear conductance-change characteristics under identical pulses. However, abrupt conductance-change characteristics are observed during the potentiation process. Thus, we use only the device characteristics of the depression part for the neuromorphic system. An excellent classification accuracy is achieved due to the linear conductance-change characteristics and optimized pulse conditions. [ABSTRACT FROM AUTHOR]

In our earlier work, we presented a percolation theory-based analytical model to estimate FinFET’s VT distribution due to fin edge roughness. The earlier models in the literature were based on minimum fin width, the limitations of which were discussed in detail. In this paper, we advance the percolation theory-based model to capture the variability in all key-device parameters, viz. I \mathrm{\scriptscriptstyle ON} , I \mathrm{\scriptscriptstyle OFF} , subthreshold slope, and VT . The entire distribution of these parameters obtained by the model is presented and compared against stochastic TCAD to demonstrate excellent match. The model reduces rms error in $\mu $ of various parameters by 5%–60%, and 20%–50% in $\sigma $ with respect to the minimum fin width-based models present in the literature. [ABSTRACT FROM PUBLISHER]

This paper presents the 2-D numerical simulation results of the single-event burnout (SEB) in the floating field ring (FFR) termination of a power MOSFET for the first time. We investigate the SEB triggering mechanism and SEB performance based on a 140-V typical FFR termination, and find that the structure is sensitive to SEB because of a sharp temperature rise appearing at the p+ base/n-drift junction. A 140-V hardened FFR termination (an n-type buffer layer is added between the epitaxial layer and substrate layer) is also studied in this paper that can demonstrate much better SEB performance without sacrificing the basic characteristics compared to the standard one. In addition, the hardening mechanism is explained, and the performances of the hardened structures with different buffer layer thickness are discussed. As a result, the safe operating area can reach the value of the breakdown voltage when the thickness achieves or exceeds 3~\mu \textm . [ABSTRACT FROM AUTHOR]

In this paper, a microstrip split-ring resonator microwave-induced plasma source was developed and the effect of the resonator strip width on the microplasma properties was studied. The end-goal of this paper is to implement the resonator into an in-space micropropulsion system. We thus need to understand the behavior of the microplasma to optimize the thruster performance. A range of resonators with widths from 1.5 to 6 mm were designed to generate a microplasma in argon. Simulations of the electric fields were performed to determine the peak gap electric field. Single Langmuir probe measurements were taken at a pressure of 1 torr to obtain the plasma density and electron temperature. The microwave power was varied from 4.7 to 11.34 W (37–41 dBm). The simulations showed that with an increase in the microstrip width, the maximum electric field strength is obtained for the 3-mm-wide resonator. The electron temperature is also the highest for the 3-mm-wide resonator sitting at ~5.6 eV with 11.34 W of power. However, the maximum plasma density was obtained for the 1.5-mm resonator, \sim 1.6\times 10^17/\textm^3 . There is an indirect relationship between the resonator electric field and the resulting microplasma properties. A theoretical analysis of a resonator-based miniature ion engine showed similar performance to the existing miniature ion engines. [ABSTRACT FROM PUBLISHER]

In this paper, we systematically examined the impact of fin height ( H\mathrm{ Fin} ) and fin angle ( \theta \mathrm{ Fin} ) on the ac performance parameters including total gate capacitance ( C\mathrm{ gg} ), RC delay ( C_{\mathrm{ gg}}V_{\mathrm{ DD}}/I_{\mathrm{\scriptscriptstyle ON}} ), cutoff frequency ( f_{T} ), energy ( E ), total power ( P_{\mathrm{ Total}} ), and leakage power ( P_{\mathrm{ Leakage}} ) of hybrid FinFETs at the supply voltage, V\mathrm{ DD} with on-current I\mathrm{\scriptscriptstyle ON} . The RC delay, energy, and total power consumption are the primary factors limiting the operating frequency of the high-performance devices. Therefore, these electrical parameters are needed to be addressed in the architectural level of the fin based devices. In this paper, a calibrated numerical device simulation tool is used to achieve the best device performances of 14-nm hybrid FinFETs. From the simulated current–voltage ( I – V ) and capacitance–voltage ( C – C\mathrm{ gg}V\mathrm{ DD}/I\mathrm{\scriptscriptstyle ON} , fT , CV2, P\mathrm{ Total} , and P\mathrm{ Leakage} are extracted to analyze the effect of H\mathrm{ Fin} and \theta \mathrm{ Fin} on the performance matrices of these devices. In addition, this paper proposes an optimum structural configuration for 14-nm hybrid FinFET architecture for digital application perspective. [ABSTRACT FROM AUTHOR]

This paper pays particular attention to the dynamic characteristics of dielectric barrier columnar discharge after it starts to decay based on a 2-D fluid model. Waveforms of the gas gap voltage, discharge current, and 2-D distributions of the electron density and the equipotential lines were calculated for the steady state of dielectric barrier columnar discharges in atmospheric helium. The evolution process of the discharge during its decay can be divided into four phases: phase (i), in which new discharges occur at nondischarge-column locations after the extinction of the discharge columns; phase (ii), in which the new discharges are extinguished; phase (iii), in which the axial electric field begins to reverse in the gap; and phase (iv), in which Townsend discharges occur at the discharge column locations before entering into the next columnar discharges. Via an analysis of the time evolution of the axial electron density, we show that new discharges occurred at nondischarge-column locations are Townsend discharges. An in-depth study of the reversion process of the axial electric fields at different locations shows that nonuniform accumulated surface charges play a key role in determining the spatiotemporal discharge characteristics. These results contribute toward gaining a comprehensive understanding of columnar discharges. [ABSTRACT FROM AUTHOR]

Dielectric response measurement is widely used to characterize oil/oil-impregnated pressboards in order to evaluate the condition of transformer insulation. Insulation systems with oil can exhibit voltage dependence at low frequencies. This is due to the limited number of mobile charges in the liquid, rather than to the dielectric relaxation processes that may, in some cases, be of more interest to study. This work investigates the voltage-dependent properties of oil/oil-impregnated pressboards under ac voltages with regard to the complex permittivities. Frequency-domain spectroscopy (FDS) measurements are made with a dc voltage added to the ac voltage stimulus. Considered influences are the voltage amplitudes and polarity as well as the dependence on temperature. Properties of the space-charge polarization in the oil and oil-impregnated pressboard are calculated and discussed based on the dc-biased measurements. It is seen that using the dc bias in the FDS measurements of oil/oil-impregnated pressboard can significantly decrease the voltage dependence of the results that are caused by ion drift and consequent depletion of ions from the bulk liquid. Based on the dc-biased measurements, the complex permittivity due to the linear and nonlinear polarization can be separated. [ABSTRACT FROM AUTHOR]

In this paper, a 3-dimensional method of characteristics is used to calculate the ion flow field around a metal building in the vicinity of bipolar HVDC transmission lines. The surface charges are introduced to make sure that the surface of the metal building is equipotential. An improved iterative method is proposed to solve the ion flow field. A reduced-scale test under laboratory conditions is carried out to verify the calculation results. Comparison of the results with those by Deutsch Assumption shows that although the two groups of results on the ground are in good agreement, the electric fields in space are different because the method of characteristics considers the effect of space charges on the direction of the electric field. The ion flow field around a metal building in the vicinity of a 800 kV transmission line was calculated with the method and discussed. [ABSTRACT FROM AUTHOR]

Manganese–zinc (MnZn) power ferrites own significant applications in inductors and transformers for power conversion. The performance of these components is dependent on permeability, saturation induction, core losses, and dc bias superposition characteristics of MnZn ferrites. It is worth emphasizing that excellent dc bias superposition characteristics of ferrites are beneficial for the stability and efficiency of power converters operated with both ac and dc signals. In this paper, Co2O3-doped MnZn ferrites are fabricated using a solid-state reaction method and used to investigate dc bias superposition characteristics of permeability and core losses. More importantly, the physical mechanism of the dc bias superposition characteristics is clarified. Furthermore, the effect of Co2O3 doping on the efficiency of buck circuit was also investigated. The dc bias superposition characteristics suggests potential application in power components and systems. [ABSTRACT FROM AUTHOR]

Interplanetary networks are affected by long propagation delays, intermittent connectivity, possible packet losses due to residual errors, and other impairments. To cope with these challenges, the delay-/disruption-tolerant networking (DTN) architecture utilizes the Licklider transmission protocol (LTP) as convergence layer on space links. The LTP reliable service (red) relies on Automatic Repeat reQuest, but very long propagation delays make packet layer forward error correcting (PL-FEC) codes very appealing to protect LTP segments from losses. The key advantage of FEC is that LTP retransmissions would be limited to the unlikely case of decoding failures. To this end, a new FEC-based protocol, to be inserted immediately below LTP, the erasure coding link service adapter (ECLSA), is presented here. ECLSA is completely transparent to LTP, relies on two alternative external libraries for coding/decoding, LibecDLR and OpenFEC, both using low density parity check codes and it is fully integrated with the ION DTN software package of NASA-JPL. This paper aims to provide a solid description of ECLSA, including features functional in a real deployment (such as the dynamic selection of codes). Performance is evaluated at the end of the paper, with nearly ideal results. ECLSA is released as free software and is already included in the “contrib” section of ION. [ABSTRACT FROM AUTHOR]

This paper deals with flow electrification phenomenon for turbulent flows of liquids through pipes of a circular cross section. Two models are proposed. The first one is based on the comparison of the radial fluctuant velocity magnitude with the magnitude of the diffuse layer relaxation velocity: it assumes that in the region where the fluctuant velocity is greater than the relaxation velocity the diffuse layer is totally perturbed so that the charge is homogenized by the turbulence, whereas when the relaxation velocity is greater than the fluctuant velocity the diffuse layer is considered not perturbed at all. The charge transported by the flow is then calculated with this new charge profile. The second model consists in solving the system of the diffuse layer equations perturbed by the turbulence, taking into account the eddy diffusivity; then with the profile of the charge obtained in the cross section the charge transported is calculated. Finally, the predictions of the charge transported using each model are compared in a specific case and discussed. [ABSTRACT FROM AUTHOR]

In this paper, an investigation of the control of electron energy in the atmospheric-pressure helium plasma jet produced by a needle–plane discharge system has been performed by means of the numerical simulation based on a 2-D self-consistent fluid model. Due to the consideration of practical application of the cold atmospheric-pressure plasma jet (CAPPJ) in the fields of biomedicine, in this paper, the mean electron energy (MEE) nearby the cathode plane is accounted for. The parameter dependences of the MEE have been systematically calculated. The considered parameters include the voltage amplitude and rising time $t_{r}$ of the applied voltage pulse as well as needle electrode radius. The voltage amplitude is changed in the range from 3 to 19 kV, and $t_{r}$ is from 1 to 200 ns. The spatial electric field has also been analyzed in detail because of its dominant role in controlling electron energy. In addition, the effect of electron energy on the production of the reactive species OH, O3, and H2O2 has also been investigated when considering the addition of humid air to the working gas helium. This paper gives the following significant results. For a given $t_{r}$ , the MEE increases almost linearly with increasing voltage amplitude. The effect of voltage amplitude on the MEE becomes much more evident for smaller $t_{r}$ and is obviously weak for the $t_{r}$ with a few hundreds of nanoseconds. Fixing the voltage amplitude, the MEE decreases with the increase in $t_{r}$. The dependence of the MEE on $t_{r}$ is evident for a high voltage amplitude and the reverse is true for the lower voltage amplitudes. As a whole, the higher voltage amplitude and smaller rising time $t_{r}$ or their synergism should be considered for obtaining high electron energy. Especially, an MEE of about 10 eV can be obtained, which covers the energy thresholds inducing all the processes of dissociative electron attachment to water molecule and thus is of essential importance for the production of the reactive species such as OH, H2O2, and O3 in the interactions of plasmas with the aqueous solution embedded in biofilms or tissues. The needle electrodes with different radii result in a minor variation of the MEE under the fixed voltage amplitude and $t_{r}$. Therefore, changing the radius of the needle electrode is not an effective solution to the control of electron energy in the CAPPJ. Furthermore, the parameter dependence of the spatial electric field is similar to that of the MEE, which reveals the dominant role played by the spatial electric field in controlling electron energy in CAPPJs. Considering the addition of humid air to the working gas helium, with the increase in electron energy, the averaged densities of OH and O3 increase, but that of H2O2 decreases. [ABSTRACT FROM AUTHOR]

This paper reports experimental investigation of the discharge behavior of pulse-enhanced vacuum arc evaporation (PEVAE) with titanium target. The PEVAE discharge was analyzed by optical emission spectroscopy, monitoring of substrate current and the electron probe current at different N2 pressure or arc current, respectively, compared to that of conventional dc arc. The results show that during the PEVAE process the electron probe current was significantly enhanced particularly at a higher pulsed current. An increase of up to more than 1–2 times was observed. Electron emission was substantially enhanced. The substrate current increased linearly with arc current regardless of the dc or PEVAE mode; however, the latter led to a larger current-rise slope. The substrate current with the PEVAE mode was improved to over 7 times. The optical emission spectra of plasma at nitrogen atmosphere showed that the intensities of ion species (e.g., Ti2+, Ti+, N+, N2+) gradually increased with pulsed arc current for the PEVAE mode. Electron temperature derived from Ti+ ion spectra was 0.55–0.6 eV and changed slightly in the PEVAE mode or dc mode. The increase in plasma spectral intensity is caused by the plasma density increase from larger ion density. These results imply that PEVAE may be an effective technique for film deposition of better microstructure and properties due to higher substrate current induced by larger electron emission and plasma density. [ABSTRACT FROM AUTHOR]

In this paper, the charge-plasma structure over the source/drain region is incorporated into a dopingless junctionless transistor for obtaining the superior immunity of line edge roughness (LER). An optimized on/off current ratio is observed by using numerical simulations. It is also demonstrated that the proposed charge-plasma junctionless transistor (CP-JLT) is insensitive to the variation of LER magnitude. We further reveal the physics that LER affects the electrical characteristics of CP-JLT. Channel minimal width position variation and channel width variation are put forward to explore the impact of LER for the first time. It is observed that the LER affects the ${I}_{\text {ON}}$ of CP-JLT due to the changes of the source width caused by channel minimal width position variation, whereas the LER affects the ${I}_{\text {OFF}}$ , SS, and ${V}_{\text {th}}$ mainly through channel width variation. It is thus proved to be a helpful guide to suppress the LER variation of CP-JLT. [ABSTRACT FROM AUTHOR]