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In this contribution, we aim at supporting theoretical transistor material design using a combination of electronic structure theory, transport simulations, and local current analysis. Our effort f...

In CSAMT exploration, the using of the artificial sources not only improves the signal-to-noise ratio of the data, but also brings a series of distortion effects, such as shadow and source overprint effects. This paper attempts to introduce a distortion effect caused by the target in the survey area. Although it is often ignored, it always plagues the data interpretation. In CSAMT method, the primary current has determined direction due to the source. When the primary current encounters electrical interfaces, the induced charge will accumulate on it and generate local current, causing local distortion. The anomaly body stretches in the direction of the vertical primary current, and a false anomaly with opposite polarity appears on both sides of the target. If the direction of the primary current is different, the accumulation position of the induced charge is also different, which will result in different shapes of the anomalies in observed data. This paper confirms the existence of the distortion by taking four simple models as examples and explains it from the physical mechanism. On this basis, the paper summarizes the relationship between inversion and distortion. If our code can simulate the distortion effect in the forward, we do not need to remove it before the inversion. Otherwise, it must be removed.

The local overheating effect induced by the uneven distribution of current density is a crucial physical phenomenon during the spark plasma sintering (SPS) of metallic powder, which can promote the densification. In order to investigate the local effects of current on densification kinetics behaviors of tungsten powder during SPS, an electromigration-creep model was constructed by introducing the local current density and was used to describe the densification process. The numerical calculation based on the model indicates that the local effect of electric current can induce a certain impact on densification during SPS at the intermediate sintering stage, in which an extremely high local current density is generated. Additionally, with the decrease of porosity, the local effect of electric current on densification is weakened.

In this study, the evolution of the electrical resistivity of metal powders during densification and the resulting current flow through punch, powder compact, and die is investigated. The e...

We report analysis of a recent model for local current density distribution along the air channel in a PEM fuel cell. Analytical solution for the case of small cell ohmic resistivity is obtained. An algorithm for numerical solution of the model equations is developed for practically important case when the cell polarization curve and ohmic resistivity are known. Good agreement between the calculated and experimental shapes of the local current density is demonstrated. Cell ohmic resisitivty greatly homogenizes the distribution of local current. A Python code for local current calculation is available for download. Keywords: PEM fuel cell, Local current distribution, Modeling, Experiment

Plastics have been found in several compartments in Antarctica. However, there is currently no evidence of their presence on Antarctic glaciers. Our pilot study investigated plastic occurrence on two ice surfaces (one area around Uruguay Lake and another one around Ionosferico Lake) that constitute part of the ablation zone of Collins Glacier (King George Island, Antarctica). Our results showed that expanded polystyrene (EPS) was ubiquitous, ranging from 0.17 to 0.33 items m−2, whereas polyester was found only on the ice surface around Uruguay Lake (0.25 items m−2). Furthermore, we evaluated the daily changes in the presence of plastics in these areas in the absence of rainfall to clarify the role of the wind in their transport. We registered an atmospheric dry deposition rate between 0.08 items m−2 d−1 on the ice surface around Uruguay Lake and 0.17 items m−2 d−1 on the ice surface around Ionosferico Lake. Our pilot study is the first report of plastic pollution presence on an Antarctic glacier, possibly originated from local current and past activities and likely deposited by wind transport.

In this paper, we shall present an analytical solution for current density from a sharp tip in the tip-to-plate configuration, with an applied dc voltage bias, using the methods of variational calculus. We shall also show that when the radius of the tip tends to infinity, we get back the current density formula for the classical Child-Langmuir (CL) law for a flat surface. The local current density near the tip is found to be much higher than the current density in the classical CL configuration. The results seem to be in agreement with the recent numerical simulations of the current density near a sharp tip.

Using a recently proposed method [Y. Meng, C. Liu, and K. L. Zhang, arXiv:1910.11597v3], we study the two-photon decay rate of ${\ensuremath{\eta}}_{c}$ using two ${N}_{f}=2$ twisted mass gauge ensembles with lattice spacings 0.067 fm and 0.085 fm. The results obtained from these two ensembles can be extrapolated in a naive fashion to the continuum limit, yielding a result that is consistent with the experimental one within two standard deviations. To be specific, we obtain the results for two-photon decay of ${\ensuremath{\eta}}_{c}$ as $\mathcal{B}({\ensuremath{\eta}}_{c}\ensuremath{\rightarrow}2\ensuremath{\gamma})=1.29(3)(18)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ where the first error is statistical and the second is our estimate for the systematic error caused by the finite lattice spacing. It turns out that Ward identity for the vector current is of vital importance within this new method. We verify that the Ward identity is violated for local current with a finite lattice spacing, however it will be restored after the continuum limit is taken.

Methylammonium lead iodide perovskite solar cells with Zn1-xMgxO buffers (hole-blocking layers) were fabricated to optimize conduction band offset (CBO) of buffer/perovskite absorber interface. The Zn1-xMgxO films were prepared by sol-gel and sputtering methods. It is disclosed that the Zn1-xMgxO buffers with increasing [Mg]/([Mg] + [Zn]) from 0 (pure ZnO) to 0.15 prepared by the sol-gel method lead to the enhancement of conversion efficiency (η) from 10.7 to 15.1%, attributed to the improvement of the CBO. However, the Zn1-xMgxO buffers with enhancing [Mg]/([Mg] + [Zn]) from 0 to 0.10 deposited by the sputtering method yield the decrease in η from 6.6 to 5.6%. The lower η in the case of the sputtering method is mainly caused by the lower short-circuit current density (JSC). According to micro-scale current path distributions of ZnO-coated SnO2:F (FTO) substrates, local current easily flows in case of ZnO-coated FTO sample by sol-gel method. On the other hand, the local current hardly flows especially at peak regions of sample surface in case of ZnO-coated FTO sample by sputtering method. This is because ZnO (or Zn1-xMgxO with [Mg]/([Mg] + [Zn]) of 0) by sputtering has higher resistance than that by sol-gel method and tends to be formed on peak regions of the FTO surface. Consequently, the low JSC of the perovskite solar cells with the buffer by sputtering method is observed.

We explore solar wind re-acceleration during their passage through reconnecting current sheets in the interplanetary space using the particle-in-cell approach. We investigate particle acceleration in 3D Harris-type reconnecting current sheets with a single or multiple X-nullpoints taking into account the ambient plasma feedback to the presence of accelerated particles. We also consider coalescent and squashed magnetic islands formed in the current sheets with different magnetic field topologies, thickness, ambient density, and mass ratios. With the PIC approach, we detected distinct populations of two groups of particles, transit and bounced ones, which have very different energy and asymmetric pitch-angle distributions associated with the magnetic field parameters. We present a few cross-sections of the simulated pitch-angle distributions of accelerated particles and compare them with the in-situ observations of solar wind particles. This comparison indicates that locally generated superthermal electrons can account for the counter-streaming ‘strahls’ often observed in pitch-angle distribution spectrograms of the satellites crossing heliospheric current sheets.

The paper presents the results from developing a new type of geoelectric instrument, a local current gauge. The operational principle of this gauge is based on measuring the electric current density and not the potential difference. The main features of this primary field sensor are described and analyzed. The characteristics of the operational prototype of the gauge are given. The main possible applications of the gauge are considered, including geoelectric and seismoelectric monitoring in a geological environment, as well as geoelectric monitoring and exploration of waterbodies.

International audience; Experimental results based on in-situ measurements at the interface between the catalyst layer and the gas diffusion layer (GDL) on the cathode side at the channel e rib scale show an interesting variation of the current density distribution as the mean current density is increased. It is found that the local current density below the rib median axis corresponds to a maximum at low to intermediate mean current densities and to a minimum when the mean current density is sufficiently high. Also, the higher is the current density, the more marked the minimum. From numerical simulations, it is shown that the current density distribution inversion phenomenon is strongly correlated to the liquid water zone development within the GDL.

Water and nitrogen can accumulate in the anode channel in proton exchange membrane fuel cells (PEMFCs) with dead-ended anode (DEA) and can affect cell performance significantly. In this paper, the cell performance characteristics in DEA PEMFCs with three different anode flow fields under two operating modes are studied through measuring the cell voltages and local current densities. The effect of the anode exit reservoir is also studied for the three different anode flow fields. The experimental results show that the interdigitated flow field has the most stable cell performance under both constant pressure and pressure swing supply modes. Parallel and serpentine flow fields lead to very non-uniform local current distributions under constant pressure supply mode and experience severe fluctuations and spikes in local current densities under pressure swing supply mode. The results also show that anode pressure swing supply mode can achieve more stable cell performance than anode constant pressure supply mode for parallel and serpentine anode flow fields. The anode exit reservoir can significantly improve cell performance stability for parallel and serpentine flow fields, but has no significant effect on interdigitated flow fields. Besides, the results further show that PEMFCs with DEA can maintain very stable operation with anode serpentine flow field and an anode exit reservoir under pressure swing operation.

Thin liquid electrolyte films are frequently used in electrochemical systems, such as energy devices and sensors, where they play an important role in determining the performance of such devices. However, it is difficult to experimentally determine the electrochemical behavior of these thin liquid films on electrodes. Here we investigated the uneven distribution of currents on an electrode covered with a thin liquid electrolyte film using a segmented Pt array electrode. A combination of experimental and simulation studies revealed that local ionic resistances governed the active positions of electrodes for the oxygen reduction reaction. These results demonstrate that segmented array electrodes are powerful tools for investigating the unique electrochemical features of thin liquid electrolyte films. Keywords: Liquid films, Current distribution, Array electrodes, Gas diffusion electrodes

Early Warning of Space Weather phenomena is one of the most important products produced by Mexican Space Weather Service (SCiESMEX). The aim is to deliver a verified warning to Mexican National Center for Disaster Prevention (CENAPRED) as well as to general public in near-real time automatically. First, the international pubic warning (or alert) is produced by Space Weather Prediction Center of National Oceanic and Atmospheric Administration, U.S.A. Further, the alert is received by SCiESMEX system, decodified, translated in Spanish and put in the context of local current conditions. The alerts are transformed and validated in agreement to Mexican policies of civil protection and CENAPRED protocols. The automatic system segments the information and delivers the corresponding web- page-alerts, emails, twits, facebook messages and SMS. The latency of the alert is 5 minutes. The code is running since January of 2015 without major interruptions.

Consistent performance of Li metal electrode (LME) relies on well-distributed current across the electrode surface. Lithium plating and dendrite growth are challenging issues for LME performance in high-energy rechargeable Li battery (RLB) development. The morphology of Li plating is affected by local current density variations on LME. A three-dimensional RLB cell model is used to study current density variations induced by cathode particle size. Smaller cathode particles show lower variances in the current density distribution throughout the separator. The results suggest particle size could affect uniformity of Li plating, propensity for dendrite formation and ultimately cycle life of RLB.

The discontinuity of a spin-current through an interface caused by spin-orbit coupling is characterized by the spin memory loss (SML) parameter {\delta}. We use first-principles scattering theory and a recently developed local current scheme to study the SML for Au|Pt, Au|Pd, Py|Pt and Co|Pt interfaces. We find a minimal temperature dependence for nonmagnetic interfaces and a strong dependence for interfaces involving ferromagnets that we attribute to the spin disorder. The SML is larger for Co|Pt than for Py|Pt because the interface is more abrupt. Lattice mismatch and interface alloying strongly enhance the SML that is larger for a Au|Pt than for a Au|Pd interface. The effect of the proximity induced magnetization of Pt is negligible.

In several OECD countries employer federations and unions fix skill-specific wage floors for all workers in an industry. One view of those “explicit” contracts argues that the prevailing wage structure reflects the labor market conditions back at the time when those contracts were bargained, with little space for renegotiation. An alternative view stresses that only workers close to the minima are affected by wage floors and that the wage structure reacts to current labor market conditions. We disentangle both models using a novel data set that combines more tan 1,000 signature dates and 15,000 wage floors set in the metal working industry with labor market histories of metal workers drawn from Social Security records in Italy and Spain. An increase in the contemporaneous local unemployment rate of 1 p.p. diminished contemporaneous mean wages by about 0.45 p.p. between 2005 and 2013 in both countries. Instead, a 1 p.p. higher unemployment rate back at the time of contract renewal reduced wages by 0.7 p.p., an impact driven by wages close to the negotiated wage floors. Even though the evidence for earlier periods is mixed in Italy, the results do not support the view that the wage structure reflects labor market conditions at the time of bargaining. The results support the hypothesis that (most) wages respond to local current unemployment rate, although the estimated elasticity falls short of the prediction of an off-the-shelf bargaining model.

The work is aimed to the study of materials based on lead selenide PbSe obtained by chemical bath deposition from aqueous solutions. The layers are studied with atomic force microscopy (topography and local current-voltage characteristics) and Raman spectroscopy.

Motivated by the recent experimental realization of the topological Anderson insulator and research interest on the topological quasicrystal lattices, we investigate the effects of disorder on topological properties of a two-dimensional Penrose-type quasicrystal lattice that supports the quantum spin Hall insulator (QSHI) and normal insulator (NI) phases in the clean limit. It is shown that the helical edge state of the QSHI phase is robust against weak disorder. Most saliently, it is found that disorder can induce a phase transition from NI to QSHI phase in the quasicrystal system. The numerical results based on a two-terminal device show that a quantized conductance plateau can arise inside the energy gap of the NI phase for moderate Anderson disorder strength. Further, it is confirmed that the local current distributions of the disorder-induced quantized conductance plateau are located on the two edges of the sample. Finally, we identify this disorder-induced phase as topological Anderson insulator phase by computing the disorder-averaged spin Bott index.

An efficient technique for improving the accuracy of the domain Green's function method (DGFM) for the analysis of large finite antenna arrays with strong mutual coupling, is presented. The technique employs rigorous method of moments (MoM) analysis on strongly-coupled local domains. All antenna elements outside a local neighbourhood are still handled according to the standard DGFM approximation. This allows for maintained accuracy in case of very high local current variations and strong mutual coupling scenarios. A further improvement is presented, in order for the technique to be accurate for antenna arrays containing passive elements. The method maintains the low memory consumption and amenability to parallelization of the standard DGFM, but with improved accuracy.

The work on production capacity expansion of hydrogen peroxide plants is part of an extensive research. In this research, the expansion of hydrogen peroxide plant, including the local current production and market demands of hydrogen peroxide has been highlighted. Hydrogen peroxide (H2O2) is one of the basic chemicals. The market size of hydrogen peroxide in Bangladesh has been ever bigger than caustic soda. Textile, Dyeing, Medicine, Pharmaceuticals, Water Treatment, Soap, Pulp and Paper Industries are using hydrogen peroxide (H2O2) as huge quantity. Recently new application is developed for hydrogen peroxide in the effluent treatment of various organic wastes of refineries and other chemical industries. In Bangladesh, there are only four plants which are producing various grades and qualities of hydrogen peroxide. Among these, three plants are producing the 50.00% (w/w) and one plant is producing the 35.00% (w/w) concentration of hydrogen peroxide. But locally, the consumption of 50.00% (w/w) is higher than 35.00% (w/w) concentration of hydrogen peroxide. The current production capacity of hydrogen peroxide in Bangladesh is not adequate to meet the country's requirement. In Bangladesh, production of hydrogen peroxide is about 190 Ton Per Day (TPD) but demand is 350 Ton per Day (TPD) which is higher than the local production. In that case, some quantity of 50.00% (w/w) concentrates of hydrogen peroxide is being imported from foreign countries like as India, China, Korea and Thailand. To avoid imports the hydrogen peroxide and to meet the requirement of local consumers, either needs to install a new production plant or increase the capacity of the existing plant. Chemical Engineers recommend that the expansion of local plants is better than newly installed the plant and it will more competence. The main purpose of the study to introduce the answer regarding the basic question, "how will we expand the capacity of an existing H2O2 plant?" In this study, a complete expansion and operation data of the H2O2 manufacturing plant have been shown so that the plant can be run efficiently. Beside this, the properties, manufacturing procedures, applications and local demanding of hydrogen peroxide are briefly discussed in this study. Finally, this invention will be helpful for the engineering team, operation team and marketing team so that they can implement their own jobs in the expansion project.

Harmonic analysis has been used in corrosion measurements for several decades. During this period the method has been refined and developed. Nevertheless, the technique has not been applied to properties determination in local scale yet. This paper is focused on local corrosion current measurements based on harmonic analysis. For this purpose, a non-linear nature of electrode processes is used and measured in local scale applying Harmonic Analysis Microscope (HAM).

The morphological evolution of zinc during electrodeposition from an alkaline zincate solution, i.e., corresponding to charging operation in secondary zinc batteries, was investigated. The initiation and propagation of mossy structures were particularly focused; mossy structures represent one of the undesired, irregular morphologies at low cathodic overpotential. Scanning electron microscopy observations showed that mossy structures formed transiently from layer-like morphology followed by the formation of protrusions with a size of submicrometers. These protrusions still exhibited layer-like features in the initial stage. In addition to this transition behavior, the propagation of mossy structures was monitored in situ by optical microscopy. At −5.0 mA cm−2, mossy structures formed successively and propagated, while there was no clear change in layer-like morphology during deposition outside these characteristic structures. At −20 mA cm−2, the layer-like growth proceeded for longer duration and the population of the mossy structures apparently decreased. However, they continuously increased in size followed by successive formation of mossy structures once initiated. From these results, growth mode of zinc at low cathodic overpotential transiently changed from layer-like growth to mossy structure evolution accompanied with dynamic variations in local current density.

We analyzed the distribution of suspended sediments concentration (SSC) in the Yellow River Estuary based on data from GaoFen-1 (GF-1), which is a high-resolution satellite carrying a wide field-of-view (WFV) sensor and panchromatic and a multispectral (PMS) sensor on it. A new SSC retrieval model for the wide field-of-view sensor (M-WFV) was established based on the relationship between in-situ SSC and the reflectance in blue and near infrared bands. SSC obtained from 16 WFV1 images were analyzed in the Yellow River Estuary. The results show that (1) SSC in the study area is mainly 100–3500 mg/L, with the highest value being around 4500 mg/L. (2) The details of suspended sediment injection phenomenon were found in the Yellow River Estuary. The SSC distribution in the coastal water has two forms. One is that the high SSC water evenly distributes near the coast and the gradient of the SSC is similar. The other is that the high SSC water concentrates at the right side of the estuary (Laizhou Bay) with a significantly large area. Usually, there is a clear-water notch at the left side of the estuary. (3) Currents clearly influenced the SSC distribution in the Yellow River Estuary. The SSC gradient in the estuary was high against the local current direction. On the contrary, the SSC gradient in the estuary was small towards the local current direction. Eroding the coast and resuspension of the bottom sediments, together with currents, are the major factors influencing the SSC distribution in nearshore water in the Yellow River Estuary.

Electrochemical exfoliation of graphite is one of the promising methods for the mass-production of graphene oxide (GO). The analysis of chemical condition, structure, and the electrical property of graphene-like materials, which is usually evaluated by X-ray photoelectron spectroscopy or micro Raman spectroscopy, is important for the practical application. However, the information obtained by these instruments are spatially averaged. In this report, electrical property of mono-layer electrochemically-exfoliated GO (EGO) sheet was directly measured by conductive atomic force microscopy (C-AFM). Although there was little difference between EGO and GO synthesized by conventional chemical oxidation routes (CGO) in terms of chemical and structural characteristics, the electrical conductivity of EGO was much higher (27 000 S m−1) than that of CGO which is considered as the insulating material. These results proved the significance of C-AFM for unveiling the relationship between the structure and the electrical properties of graphene-like materials.

Pulsed surface discharge on water has been given attention as a water purification technology and material synthesis method. The contribution of this study is to clarify the plasma state of a positive pulsed surface discharge on water. Although the pulse width of the current dramatically decreased with an applied voltage ranging from 10 to 20 kV under a conductivity of water of 1 mS cm-1 and a water depth of 2 mm, the plasma state in the vicinity of the needle electrode was a local thermodynamic equilibrium (LTE) state. Validation of the LTE was performed by the McWhirter criterion. On the other hand, the propagating discharge along the water surface was supposed to be in non-LTE state. Consequently, the pulsed surface discharge on water was in mixed states of LTE and non-LTE., Japanese Journal of Applied Physics, 59, art.no.SHHA07; 2020

We report on the evolution of dipolarization and associated disturbances of the near-Earth current sheet during a substorm on 27 October 2007, based upon Cluster multi-point, multi-scale observations of the night-side plasma sheet at X~−10 RE. Three dipolarization events were observed accompanied by activations on ground magnetograms at 09:07, 09:14, and 09:22 UT. We found that all these events consist of two types of dipolarization signatures: (1) Earthward moving dipolarization pulse, which is accompanied by enhanced rapid Earthward flux transport and is followed by current sheet disturbances with decrease in BZ and enhanced local current density, and subsequent (2) increase in BZ toward a stable level, which is more prominent at Earthward side and evolving tailward. During the 09:07 event, when Cluster was located in a thin current sheet, the dipolarization and fast Earthward flows were also accompanied by further thinning of the current sheet down to a half-thickness of about 1000 km and oscillation in a kink-like mode with a period of ~15 s and propagating duskward. Probable cause of this "flapping current sheet" is shown to be the Earthward high-speed flow. The oscillation ceased as the flow decreased and the field configuration became more dipolar. The later rapid flux transport events at 09:14 and 09:22 UT took place when the field configuration was initially more dipolar and were also associated with BZ disturbance and local current density enhancement, but to a lesser degree. Hence, current sheet disturbances induced by initial dipolarization pulses could differ, depending on the configuration of the current sheet.

This paper describes a novel flexible prototype device capable of both RF and microwave delivery for coagulation and ablation. The concept offers additional freedom to tailor the ablation profile in addition to key multimodality benefits (adjustable profile, thermal management, local current path, larger ablation). Finite element analysis, the prototype device and ex-vivo testing is presented. Good agreement was achieved between simulated and ex-vivo ablation profiles along with successful validation of the antenna design capable of delivering both RF and microwave energy. To the best of the authors knowledge, this is the first ablation antenna structure reported that combines the delivery of RF and microwave energy to produce optimal ablation volumes.

We present a pedagogical review of current density simulation in molecular junction models indicating its advantages and deficiencies in analysis of local junction transport characteristics. In particular, we argue that current density is a universal tool which provides more information than traditionally simulated bond currents, especially when discussing inelastic processes. However, current density simulations are sensitive to choice of basis and electronic structure method. We note that discussing local current conservation in junctions one has to account for source term caused by open character of the system and intra-molecular interactions. Our considerations are illustrated with numerical simulations of a benzenedithiol molecular junction., 10 pages, 6 figures

Purpose– The purpose of this paper is to establish and compare the provision of information literacy (IL) skills to university students both at undergraduate and graduate levels in South Africa (SA) and the United Arab Emirates (UAE). This could in turn inform the development of appropriate/suitable IL programmes to support teaching and learning.Design/methodology/approach– A review of available scholarly papers is performed for information collection.Findings– The findings can identify variations in IL provision within and across disciplines, deficiencies in local current and ongoing research.Research limitations/implications– It must be noted that this is a review and conclusions from it are expected to reveal areas that require more in-depth study.Practical implications– The study’s contribution to the field of IL lies in its revelation of what is understood by IL provision and how the ACRL standards are used to guide practice in the two different regions of the world.Originality/value– The study is the first of its kind which compares IL practices at university libraries in SA and the UAE. It will assist policymakers and librarians in the development of appropriate IL programmes in support of teaching and learning.