Electric Fields Of Order Research Articles

Precise micromotion compensation of a tilted ion chain

Excess micromotion can be a substantial source of errors in trapped-ion based quantum processors and clocks due to the sensitivity of the internal states of the ion to external fields and motion. This problem can be fixed by compensating background electric fields in order to position ions at the RF node and minimize their driven micromotion. Here we describe techniques for compensating ion chains in scalable surface ion traps. These traps are capable of cancelling stray electric fields with fine spatial resolution in order to compensate multiple closely spaced ions due to their large number of relatively small control electrodes. We demonstrate a technique that compensates an ion chain to better than 5 V/m and within 0.1 degrees of chain rotation.

Intrinsic Nonlinear Planar Hall Effect.

We propose an intrinsic nonlinear planar Hall effect, which is of band geometric origin, independent of scattering, and scales with the second order of electric field and first order of magnetic field. We show that this effect is less symmetry constrained compared with other nonlinear transport effects and is supported in a large class of nonmagnetic polar and chiral crystals. Its characteristic angular dependence provides an effective way to control the nonlinear output. Combined with first-principles calculations, we evaluate this effect in the Janus monolayer MoSSe and report experimentally measurable results. Our work reveals an intrinsic transport effect, which offers a new tool for material characterization and a new mechanism for nonlinear device application.

Monte-Carlo Calculations (GEANT4) of Ions Resulting of the Irradiation and Interaction of a Static Electric Field and Some Experimental Tests – an Attractive Way to Improve the Enhancement of the Yield of Hydrogen

The past decade has emerged a growing interest in the electrolysis and Hydrogen technology as a surrogate of the conventional energy sources. Many novel materials have been tested to improve the Hydrogen yield and to reach a breakthrough with them. In the present analysis the electrolysis with additional 6 MV ionizing radiation produced by a linear accelerator has been tested in order to suggest γ-radiation of radioactive waste of nuclear reactors and other sources, which is the goal of this study. For this purpose, a box consisting of laboratory glass filled with water and capacitors as electrodes has been used for the performance of the tests. The experimental tests have provided significant differences of the Hydrogen release, if the test phantom has been subjected to radiation and the comparison without it. A theoretical insight obtained by the consideration an extension of the diffusion equation by a static electric field in order to describe the transport of ions. Quantitative examinations have been made possible by Monte Carlo calculations with GEANT4, which provided good agreement with experimental data, since this code is also applicable by inclusion of external electric and magnetic fields.

Laser Written Stretchable Diffractive Optic Elements in Liquid Crystal Gels

Direct laser writing (DLW) in liquid crystals (LCs) enables a range of new stimuli-responsive functionality to be realized. Here, a method of fabricating mechanically tunable diffraction gratings in stretchable LC gels is demonstrated using a combination of two-photon polymerization direct laser writing (TPP-DLW) and ultraviolet (UV) irradiation. Results are presented that demonstrate the fabrication of a diffraction grating that is written using TPP-DLW in the presence of an electric field in order to align and lock-in the LC director in a homeotropic configuration. The electric field is subsequently removed and the surrounding regions of the LC layer are then exposed to UV light to freeze-in a different alignment so as to ensure that there is a phase difference between the laser written and UV illuminated polymerized regions. It is found that there is a change in the period of the diffraction grating when observed on a polarizing optical microscope as well as a change in the far-field diffraction pattern when the film is stretched or contracted. These experimental results are then compared with the results from simulations. The paper concludes with a demonstration of tuning of the far-field diffraction pattern of a 2-dimensional diffraction grating.

The lateral electric force on an off-axis sphere in a circular cylinder.

The electrophoretic velocity of a sphere within a liquid-filled circular cylinder in a direction parallel to the cylinder axis has been studied by Yariv and Brenner (Phys. Fluids 2002, 14, 3354-3357; SIAM J. Appl. Math. 2003, 64, 423-441). We use their analyses of the electric field in order to determine the electrical force on the sphere along the cylinder radius (i.e., perpendicular to its axis) when either the radius of the sphere is small compared to that of the cylinder, or when the radius of the sphere is only slightly smaller than that of the cylinder. In both cases the force acts towards the centreline of the cylinder, and hence this force tends to stabilize electrophoresis of the sphere along the cylinderaxis.

Inverse Imaging Using Total Field Measurements

Most microwave inverse imaging algorithms rely on measurements of both the total and the incident electric field in order to estimate the dielectric properties of an unknown scattering object (SO). We propose a new technique to jointly estimate the incident field and relative permittivity of a heterogeneous dielectric object from measurements of the total electric field alone. For the first task, we express the incident field as a collection of plane waves and estimate the wave coefficients from the given data by leveraging the sparsity of the plane wave spectrum and obtain the solution via a constrained reweighted <inline-formula> <tex-math notation="LaTeX">$L_{1}$ </tex-math></inline-formula> norm minimization technique. Subsequently, we estimate the permittivity and geometry of the SO using a twofold subspace optimization method. We evaluate the performance of our algorithm on synthetically generated object and experimental data. For synthetic objects, the accuracy in reconstruction of the incident field and the relative permittivity is &#x2248;93&#x0025; for field measurements with a 15-dB signal-to-noise ratio, while the accuracy obtained for an experimental data set was &#x2248;90&#x0025;.

The Use of Iron-Enriched Yeast for the Production of Flatbread.

The most common cause of iron deficiency is an improperly balanced diet, in which the body’s need for iron cannot be met by absorption of this element from food. Targeted iron supplementation and food fortification may be the main treatments for iron deficiency in the population. However, many iron-rich supplements and foods have low bioavailability of this element. In our study, we used yeast enriched with iron ions to produce flatbread. The yeast cells accumulated iron ions from the medium supplemented with Fe(NO3)3·9H2O, additionally one of the cultures was treated with pulsed electric field in order to increase the accumulation. The potential bioavailability of iron from flatbread containing 385.8 ± 4.12 mg of iron in 100 g dry mass was 10.83 ± 0.94%. All the flatbreads had a moderate glycemic index. There were no significant differences in antioxidant activity against DPPH• between flatbread with iron-enriched and non-iron-enriched yeast. Sensory evaluation showed that this product is acceptable to consumers since no metallic aftertaste was detected. Iron enriched flatbread can potentially be an alternative to dietary supplements in iron deficiency states.

Study of Electric Field Impact on Crystallization in Tunnel Drainage Pipes in Hard Water Area

To solve the problem of blockage of crystallization in tunnel drainage pipes in hard water area, electric field devices are designed and applied in the transversal tunnel drainage pipe according to the fundamental law of crystallization. Laboratory tests were carried out to test the crystallizing tunnel drainage pipe under the effect of electric field in order to study the law of electric field impact on crystallization in tunnel drainage pipes in hard water area. The test results indicate that the arranged circumferential and parallel plate electric field devices can form an electrical field within a narrow and small space inside the pipe and influence the ion movement in water and adsorption performance between crystals and the pipe. Under the condition of full flow, the amount of crystals in the ordinary pipe without electric field treatment increases progressively along water flow direction and remains relatively uniform later. The amount of crystals along the water flow direction of the pipe treated with circumferential and parallel plate electric fields presents signs of fluctuation in the early stage and then stableness later. The amount of crystals in the fluctuating section is higher and lower in the uniform section, and its uniform section length is longer than that in ordinary pipes. Under the condition of full current, crystallizing speed declines with elapse of running time. After the electric field is imposed, crystallizing acceleration progressively decreased to a relatively lower level. Comparing three voltages of 5 V, 12 V, and 24 V, the effect of scale inhibition under 5 V is superior. When water amount in the pipe varies, the effects of scale inhibition under different electric field modes are different. The electric field effect causes the changes of the external form of calcium carbonate crystal and its surface abrasion, porous crystal, and structural looseness.

Effect of coil positioning and orientation of the quadruple butterfly coil during transcranial magnetic stimulation

Transcranial Magnetic Stimulation (TMS) is a non-invasive neuromodulation technique for treating neurological and psychiatric disorders. It is a proven technique that is safe and considered very effective when compared to conventional brain surgery or drug therapy. Researchers and clinicians are interested in understanding the distribution of the induced electric field (E-Field) during TMS and determining its effectiveness in treating neurological disorders. TMS studies are primarily focused on enhancing the focality and depth of penetration of the induced electric field in order to increase its effectiveness. Coil orientation has been confirmed to have an effect on the magnitude and direction of the induced E-Field. In this paper, we study the effect of the orientation of the novel Quadruple Butterfly Coil (QBC) on the distribution of the induced E-Field. Finite element analyses were conducted with the orientation of the QBC in steps of 15° over the vertex of two head models and about the transverse (XY –) plane and coronal (XZ –) plane of the head model. The maximum electric field intensity (E-Max) and stimulated volume of the brain (V-Half) were computed and compared to determine the optimal coil orientation.

Optimization of Non-Stationary Electric Field Parameters in Order to Increase the Efficiency of Chamber Furnaces

Topicality. The presented work is devoted to the urgent task of increasing the energy efficiency of chamber furnaces.The purpose is to solve the problem connected with optimizing the parameters of the non-stationary mode of the applied electric field in order to increase the efficiency of the chamber furnaces. Methodology. According to well-known methods of experiment planning, we obtained a set of Pareto-incomparable solutions of the chamber furnace, taking into account the voltage between the burner and the metal charge, which is the basis of the algorithm. Findings. The work proposes an innovative system acting the process of metal heating in a chamber furnace. The result is a developed chamber furnace control system, in which the optimal values of control actions at each step of the heating cycle are determined according to the created algorithm. The proposed control system is universal, because after miscalculations it produces the dynamics, according to which one needs to change the value of direct-current voltage and gas supply with a step in time to perform any given mode of metal heat treatment. The experimental studies conducted on a real chamber furnace with a bogie hearth at Zaporozhye Titanium and Magnesium Combine confirmed this. The analysis of the obtained metal annealing temperature curve showed that the implementation of the optimal values of the control actions, obtained using the developed algorithm, provides a high uniformity and better quality heating of the metal. The dynamics of gas consumption by the chamber furnace during the heating cycle in the basic mode, without voltage supply, and under the condition of its use in accordance with the performed optimization testify to the possibility of significant energy efficiency improvement of the considered furnaces. Conclusions. For the first time we proved the possibility and efficiency of using a non-stationary electric field in the furnace chamber as a control action, which confirms the originality of the obtained results. The practical value of the research is that the developed control algorithm is universal in terms of metal heat treatment and can be used in chamber furnaces of any industrial enterprise, while one heating cycle reduces the consumption of natural gas by more than 10 %.

Characterization of Nematic Liquid Crystals at Microwave Frequencies

The use of nematic liquid crystal (LC) mixtures for microwave frequency applications presents a fundamental drawback: many of these mixtures have not been properly characterized at these frequencies, and researchers do not have an a priori clear idea of which behavior they can expect. This work is focused on developing a new procedure for the extraction of the main parameters of a nematic liquid crystal: dielectric permittivity and loss tangent at 11 GHz under different polarization voltages; splay elastic constant K11, which allows calculation of the threshold voltage (Vth); and rotational viscosity γ11, which allows calculating the response time of any arbitrary device. These properties will be calculated by using a resonator-based method, which is implemented with a new topology of substrate integrated transmission line. The LC molecules should be rotated (polarized) by applying an electric field in order to extract the characteristic parameters; thus, the transmission line needs to have two conductors and low electric losses in order to preserve the integrity of the measurements. This method was applied to a well-known liquid crystal mixture (GT3-23002 from MERCK) obtaining the permittivity and loss tangent versus bias voltage curves, the splay elastic constant, and the rotational viscosity of the mixture. The results validate the viability of the proposed method.

High-resolution sampling of beam-driven plasma wakefields

Plasma-wakefield accelerators driven by intense particle beams promise to significantly reduce the size of future high-energy facilities. Such applications require particle beams with a well-controlled energy spectrum, which necessitates detailed tailoring of the plasma wakefield. Precise measurements of the effective wakefield structure are therefore essential for optimising the acceleration process. Here we propose and demonstrate such a measurement technique that enables femtosecond-level (15 fs) sampling of longitudinal electric fields of order gigavolts-per-meter (0.8 GV m−1). This method—based on energy collimation of the incoming bunch—made it possible to investigate the effect of beam and plasma parameters on the beam-loaded longitudinally integrated plasma wakefield, showing good agreement with particle-in-cell simulations. These results open the door to high-quality operation of future plasma accelerators through precise control of the acceleration process.

Direct Visualization of Current-Stimulated Oxygen Migration in YBa2Cu3O7−δ Thin Films

The past years have witnessed major advancements in all-electrical doping control on cuprates. In the vast majority of cases, the tuning of charge carrier density has been achieved via electric field effect by means of either a ferroelectric polarization or using a dielectric or electrolyte gating. Unfortunately, these approaches are constrained to rather thin superconducting layers and require large electric fields in order to ensure sizable carrier modulations. In this work, we focus on the investigation of oxygen doping in an extended region through current-stimulated oxygen migration in YBa2Cu3O7-δ superconducting bridges. The underlying methodology is rather simple and avoids sophisticated nanofabrication process steps and complex electronics. A patterned multiterminal transport bridge configuration allows us to electrically assess the directional counterflow of oxygen atoms and vacancies. Importantly, the emerging propagating front of current-dependent doping δ is probed in situ by optical microscopy and scanning electron microscopy. The resulting imaging techniques, together with photoinduced conductivity and Raman scattering investigations, reveal an inhomogeneous oxygen vacancy distribution with a controllable propagation speed permitting us to estimate the oxygen diffusivity. These findings provide direct evidence that the microscopic mechanism at play in electrical doping of cuprates involves diffusion of oxygen atoms with the applied current. The resulting fine control of the oxygen content would permit a systematic study of complex phase diagrams and the design of electrically addressable devices.

Recording the Vertical Component of the Electric Field in Magnetotelluric Sounding

Abstract —Magnetotelluric sounding (MTS) usually records variations in five components of the electromagnetic field. Interpretation of distorted MT responses of an inhomogeneous earth may be problematic. The problem can be solved by recording additionally the vertical component Ez of the electric field in order to improve the quality of inversion and to gain more information. Currently Ez variations are estimated by measuring voltage on a vertical line immersed in water. The land measurements of this kind require special drilling or using the existing boreholes, which is not always feasible. Otherwise, a circular electric dipole (CED) can be used as a receiver to record the electric field behavior along the vertical component. Its applicability to MT soundings is analyzed in this paper.

Velocity Saturation Effect on Low Frequency Noise in Short Channel Single Layer Graphene Field Effect Transistors

Graphene devices for analog and RF applications are prone to Low Frequency Noise (LFN) due to its upconversion to undesired phase noise at higher frequencies. Such applications demand the use of short channel graphene transistors that operate at high electric fields in order to ensure a high speed. Electric field is inversely proportional to device length and proportional to channel potential so it gets maximized as the drain voltage increases and the transistor length shrinks. Under these conditions though, short channel effects like Velocity Saturation (VS) should be taken into account. Carrier number and mobility fluctuations have been proved to be the main sources that generate LFN in graphene devices. While their contribution to the bias dependence of LFN in long channels has been thoroughly investigated, the way in which VS phenomenon affects LFN in short channel devices under high drain voltage conditions has not been well understood. At low electric field operation, VS effect is negligible since carriers velocity is far away from being saturated. Under these conditions, LFN can be precicely predicted by a recently established physics-based analytical model. The present paper goes a step furher and proposes a new model which deals with the contribution of VS effect on LFN under high electric field conditions. The implemented model is validated with novel experimental data, published for the first time, from CVD grown back-gated single layer graphene transistors operating at gigahertz frequencies. The model accurately captures the reduction of LFN especially near charge neutrality point because of the effect of VS mechanism. Moreover, an analytical expression for the effect of contact resistance on LFN is derived. This contact resistance contribution is experimentally shown to be dominant at higher gate voltages and is accurately described by the proposed model.

EFFECT OF ELECTRIC FIELD ON GAS CONTENT OF CAST IRON

The effect of electric field on the gas content of cast iron has been experimentally established on the basis of electrochemical studies in the system “liquid cast iron – slag – gas phase”. The author has carried out the studies aimed at obtaining cast iron sparingly alloyed with nickel, equal to Ni-resist cast iron in its mechanical and performance characteristics. For this purpose, austenitic cast irons melted in induction furnace with electrocorundum lining have been studied. Samples prepared from the obtained cast iron have been subjected to further treatment with electric field in order to research the influence of static electric field on fixation of atomic nitrogen in the alloy, and ultimately, on the structure of metal matrix. According to the experimental data, the effect can be enhanced by application of electric field. The application of negative charge to metal appears to be more effective, although, in case of anode metal, certain “capture” of nitrogen in cast iron also occurs. This may be explained by the fact that, at the initial moment of time, there is a stationary electric field between the movable (free) electrode and surface of the melt, where the charged particles are stationary in this reference frame, which is registered as no current by ampere-meters integrated in the circuit. The application of static electric field facilitates is capture of nitrogen in cast iron. According to further experiments, at 8 – 9 % of Ni, it is necessary to apply significant voltage for the manifestation of this influence. The studies have shown that the issue of stabilizing austenite with nitrogen in cast iron was not so simple, and, apparently, the influence of the field in case of the introduction of nitrided ferrochrome affected decomposition of nitrides, recharging of nitrogen ions, and non-equilibrium conditions of their diffusion and transition to gaseous phase. It was confirmed by a wide variation of the results of nitrogen analyses. Some samples have shown 0.04 – 0.05 % of N (with the introduction of nitrided ferrochrome, and a “minus” applied to metal), but most analyses have indicated considerably lower values. For foundry industry, electrochemical deoxidation of alloys that are difficult to deoxide by other methods, e.g. aluminum cast iron alloy, is of particular interest. Aluminum is an active element, which, in case of unfavorable arrangement of mass flows, is difficult to remove even using calcium. It leads to the emergence of Al2O3 inclusions in metal with the density close to melt, which complicates their coagulation and emersion. A double deoxidation has been tried. After the melt’s exposure lasted for 1 hour, its EMF has almost “returned” to its initial state (0.8 V). The subsequent deoxidation of melt for 15 minutes facilitated three-fold decrease in oxidation degree as compared to the initial one. Thus, the possibility of electrochemical deoxidation of iron-carbon melts and expediency of double deoxidation have been experimentally proved. As a result, the method of applying electric field in order to change the gas content of cast iron, as well as the method of practical application of electrochemical deoxidation of iron-carbon alloys have been suggested.

Initial electric field changes of lightning flashes in tropical thunderstorms and their relationship to the lightning initiation mechanism

In this paper, the key finding is that all the examined first classic Initial Breakdown (IB) pulses in tropical flashes within the reversal distance were found to be initiated by a clearly detectable Initial E-field Change or IEC (45 –CG, 32 normal IC, and 3 IC initiated by +NBE). The durations of IECs for both –CG and IC flashes in tropical storms were longer than in Florida storms. On the other hand, for the magnitudes of the E-change, the values were smaller compared to Florida storms with averages of 0.30 V/m compared to 1.65 V/m for –CG flashes, and −0.81 V/m compared to −6.30 V/m for IC flashes. The IEC process of lightning flashes in tropical regions took longer to increase the local electric field in order to produce the first IB pulse because of the smaller magnitude of E-change. On the other hand, in Florida storms, the IEC process took a shorter time to increase the local electric field to produce the first IB pulse because of the larger magnitude of E-change. We found that very high frequency (VHF) pulses for tropical thunderstorms started sometime prior to the onset of the IECs. They started between 12.69 and 251.60 μs before the initiation of the IEC for two normal IC flashes. The first two VHF pulses were detected alone without narrow IB pulses (fast antenna and slow antenna records) or any pulses from the B-field and dE/dt records. Furthermore, the VHF pulses for three IC flashes initiated by +NBEs were also detected before the onset of the IEC. The IEC started immediately after the detection of the +NBE. It is clear that the IEC is initiated by VHF pulses. It can be suggested that lightning is initiated by Fast Positive Breakdowns or FPBs (which emit strong VHF pulses and large +NBEs) and is followed by several negative breakdowns (weak VHF pulses and/or weak NBE-type pulses) before the IEC started. For the case of normal IC flashes, several weaker VHF pulses (mean values of 41.97 mV and 46.4 mV compared to the amplitudes of the VHF pulses of +NBEs of around 800 mV) were detected before the onset of the IEC. As FPBs can occur with a wide range of VHF strengths and E-change amplitudes, it can be suggested these weak VHF pulses accompanied by narrow IB pulses or weak NBE-type pulses detected before the onset of IEC are actually FPBs followed by negative breakdowns or several attempted FPBs.

Sulforaphane-Enriched Broccoli Sprouts Pretreated by Pulsed Electric Fields Reduces Neuroinflammation and Ameliorates Scopolamine-Induced Amnesia in Mouse Brain through Its Antioxidant Ability via Nrf2-HO-1 Activation

Activated microglia-mediated neuroinflammation plays a key pathogenic role in neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and ischemia. Sulforaphane is an active compound produced after conversion of glucoraphanin by the myrosinase enzyme in broccoli (Brassica oleracea var) sprouts. Dietary broccoli extract as well as sulforaphane has previously known to mitigate inflammatory conditions in aged models involving microglial activation. Here, we produced sulforaphane-enriched broccoli sprouts through the pretreatment of pulsed electric fields in order to trigger the biological role of normal broccoli against lipopolysaccharide-activated microglia. The sulforaphane-enriched broccoli sprouts showed excellent potency against neuroinflammation conditions, as evidenced by its protective effects in both 6 and 24 h of microglial activation in vitro. We further postulated the underlying mechanism of action of sulforaphane in broccoli sprouts, which was the inhibition of an inflammatory cascade via the downregulation of mitogen-activated protein kinase (MAPK) signaling. Simultaneously, sulforaphane-enriched broccoli sprouts inhibited the LPS-induced activation of the NF-κB signaling pathway and the secretions of inflammatory proteins (iNOS, COX-2, TNF-α, IL-6, IL-1β, PGE2, etc.), which are responsible for the inflammatory cascades in both acute and chronic inflammation. It also upregulated the expression of Nrf2 and HO-1 in normal and activated microglia followed by the lowered neuronal apoptosis induced by activated microglia. Based on these results, it may exhibit anti-inflammatory effects via the NF-κB and Nrf2 pathways. Interestingly, sulforaphane-enriched broccoli sprouts improved the scopolamine-induced memory impairment in mice through Nrf2 activation, inhibiting neuronal apoptosis particularly through inhibition of caspase-3 activation which could lead to the neuroprotection against neurodegenerative disorders. The present study suggests that sulforaphane-enriched broccoli sprouts might be a potential nutraceutical with antineuroinflammatory and neuroprotective activities.

Suppression of Electron Avalanches in Ultra-Dilute SF6-N2 Mixtures Subjected to Time-Invariant Crossed Fields

Ultra-dilute SF6 + N2 mixtures are subjected to crossed fields with the applied magnetic field normal to the electric field in order to investigate critical magnetic field values for suppression of electron avalanche growth resulting in increased dielectric strength. Electron avalanche growth inhibition together with the related electron mean energy variation and electron energy distribution functions are reported in the binary mixtures subjected to the combined fields. Even if a very small amount of greenhouse gas (SF6) is used, high dielectric strength can be achieved in the binary mixtures with 0.25%, 0.50%, 0.75%, 3%, and 7% SF6 contents subjected to the evaluated combined fields. The magnitude of the crossed magnetic field, which results in avalanche growth inhibition, decreases as the electronegativity of the mixture is increased.

Hybridization of MWCNTs and reduced graphene oxide on random and electrically aligned nanocomposite membrane for selective separation of O2/N2 gas pair

This present study demonstrates the development of high-performance polysulfone (PSf) hybrid mixed matrix membranes (MMMs) through the collaborative inclusion of multiwalled carbon nanotubes (CNTs) and reduced graphene oxide (rGO). The nanofillers are aligned by virtue of an AC electric field in order to formulate a multifunctional composite membrane structure for selective separation of O2/N2 gas. Proper alignment of the conducting nanofillers within PSf was confirmed by utilizing different microscopy and spectroscopy techniques. Hybridization of CNTS and rGO resulted in concurrent enhancement of permeability as well as the selectivity of the neat membrane. The inclusion of rGO nanosheets established a long, tortuous path hindering the permeation of gas molecules possessing the larger molecular size, while CNTs-filled MMM achieved better permeation due to their favorable intrinsic structural characteristics. The overall performance of the aligned hybrid membranes was found to be significant in contrary to single filler-based membrane systems (PSf/CNTs and PSf/rGO).