Influence Of Electric Field Research Articles

Dynamically tuning friction at the graphene interface using the field effect

Dynamically controlling friction in micro- and nanoscale devices is possible using applied electrical bias between contacting surfaces, but this can also induce unwanted reactions which can affect device performance. External electric fields provide a way around this limitation by removing the need to apply bias directly between the contacting surfaces. 2D materials are promising candidates for this approach as their properties can be easily tuned by electric fields and they can be straightforwardly used as surface coatings. This work investigates the friction between single layer graphene and an atomic force microscope tip under the influence of external electric fields. While the primary effect in most systems is electrostatically controllable adhesion, graphene in contact with semiconducting tips exhibits a regime of unexpectedly enhanced and highly tunable friction. The origins of this phenomenon are discussed in the context of fundamental frictional dissipation mechanisms considering stick slip behavior, electron-phonon coupling and viscous electronic flow.

Nonlinear optical properties of modified Möbius squared potential well: influence of electric and magnetic fields

ABSTRACT This work presents a numerical study on the electronic and optical properties of modified Möbius squared potential well in the presence of static electric and magnetic fields. The potential well is formed within GaAs/AlGaAs hetero structures. Schrödinger’s equation is solved within the framework of effective mass and envelope wave function approximations to get the wave functions and their corresponding energies of states. The optical absorption coefficients and relative refractive index changes are calculated via the expressions derived from the compact density matrix approach. The numerical results present strong blue shifts on the optical responses of modified Möbius squared potential well when the external electromagnetic fields are strengthening.

Analysis of near field mutual coupling in wideband magnetoelectric antennas array

The operating bandwidth of miniaturized magnetoelectric (ME) antenna is generally narrow due to the acoustic wave driven magneto-electromechanical resonance effect, parallel connection of multiple ME antennas with different resonant frequencies is an effective way to broaden the operating bandwidth of the antenna. This paper presents an ME antenna array consisting of three units, which are constructed of a sandwich stack of Metglas/Pb(Mg1/3Nb2/3)O3–PbTiO3/Metglas. The −3 dB operating bandwidth of 152.4–172.8 kHz is achieved, and the relative bandwidth is 12.5%. Experimental results indicated that the bias magnetic field and coupling effect between the ME antenna units significantly influence the performance of ME antenna array. A modified Butterworth–Van Dyke (MBVD) equivalent circuit model is used and improved to analyze the influence of sound waves, electric fields, magnetic fields, parasitic capacitance, and bias magnetic field on the ME antenna array. The simulation results of the MBVD equivalent circuit model are agreed well with the experimental results. The improved MBVD model is beneficial for the design of acoustic wave driven antenna array.

Snap-through instability in rotating dielectric elastomer tubes

Dielectric elastomers (DEs) have been widely used in soft robotics, high-performance actuators, and bioengineering. However, they may suffer from more failure modes than pure elastic elastomers when undergoing rotational motion. In this paper, we present a theoretical analysis of the finite deformation of rotating DE tubes, addressing the challenges associated with rotational motion in DEs. Our study focuses on the combined influence of a radial electric field and an axial pre-stretch. We numerically calculate three different materials, including neo-Hookean, Gent, and Ogden models, for rotating DE tubes and find that the snap-through instability caused by rotation occurs only in tubes with the Ogden model, resulting in dramatic deformation. Moreover, we study the effects of geometric dimensions and external loads and reveal the competition mechanism between the snap-through instability and electrical breakdown of DE tubes under external voltage. Significantly, our work presents practical thresholds that offer comprehensive guidance for designing and controlling of rotating DE tubes, preventing electrical breakdown during rapid deformation through the adjustment of external loads. This study provides novel insights and practical recommendations for the field of nonlinear deformation in rotating DE tubes.

Influence of a static electric field on magnetic materials monitored by X-ray magnetic circular dichroism

The magnetic circular X-ray dichroism (XMCD) in X-ray absorption spectroscopy (XAS) is extensively used to monitor the response of a magnetic system to an external perturbation. Application of a static external electric field to control its magnetic properties may just lead to a charge rearrangement or to a steady electric current dependent on the geometry. As it is demonstrated, the first situation can be handled with minor modifications of the standard well established schemes to calculate XAS and XMCD spectra. For the second case, however, more advanced schemes have to be used that account for the steady-state out-of-equilibrium situation. It is shown, that this can indeed be achieved by making use of the Keldysh non-equilibrium Green function formalism that allows in particular to express the X-ray absorption coefficient in terms of the corresponding greater Green function G>(E). As an alternative approach, a bi-linear response formalism is presented that can be used to calculate the modification of the XMCD spectra due to the electric field directly.

Influence of external electric field on electronic structure and optical properties of β-Ga2O3: a DFT study.

The influence of different electric fields on the electronic structure and optical properties of β-Ga2O3 was studied by GGA+U method. The results show that appropriate electric field intensity can regulate the band gap of β-Ga2O3 more effectively to improve the photoelectric characteristics. The band gap value of intrinsic β-Ga2O3 is 4.865 eV, and decreases from 4.732 to 2.757 eV with the increase of electric field intensity from 0.05 to 0.20 eV Å-1. The length of the O-Ga bond along the electric field increases the fastest with the electric field intensity, and the distance between O and Ga reaches 2.52 Å when the electric field intensity is 0.20 eV Å-1. A new peak appears in the real and imaginary parts of the dielectric function for β-Ga2O3 in the low frequency region under the electric field, and the conductivity increases obviously. The optical absorption peaks induced by the electric field were observed in the wavelength range of 400-600 nm. The optical absorption of β-Ga2O3 is enhanced with an increase of electric field intensity, exhibiting a maximum value with the electric field of 0.15 eV Å-1. The electric field above 0.15 eV Å-1 causes a decrease of optical absorption intensity.

An analysis of the spread of electric field within the cochlea for different devices including custom-made electrodes for subtotal cochleoectomy.

Cochlear implants (CIs) can restore hearing not only in patients with profound hearing loss and deafness, but also in patients following tumour removal of intra-cochlear schwannomas. In such cases, design and placement differ from conventional electrode insertion, in which the cochlea remains filled with fluid. Despite these technical and surgical differences, previous studies have tended to show positive results in speech perception in tumour patients. The purpose of this study is to retrospectively evaluate the ability to predict speech recognition outcomes using individual electric field spreads and to investigate worldwide unique tumour cases. In a retrospective analysis in a university tertiary center electric field spreads were compared between two groups of electrode designs implanted between 2009 and 2020 i.e., between lateral wall electrodes and custom-made perimodiolar electrode carriers from the same company. The voltage gradients were analysed and grouped with speech recognition results. Differences in electrical field spreads were found between lateral wall electrodes and the custom-made perimodiolar electrodes, whereas a significant influence of electric fields on scores in speech recognition cannot be demonstrated. Prediction of speech recognition outcome based on electric field propagation results seems not feasible. Significant differences in field spread between electrode arrays can be clearly demonstrated. This observation and its relevance to hearing treatment and speech recognition should therefore be further investigated in upcoming studies.

Ceramics/metals joining under the influence of electric field: A review

Ceramics/metals joining under the influence of electric field: A review

Electric Control of Thermal Contributions to the Nonlinear Optical Properties of Nitrobenzene

AbstractThermal effects are inevitable when an absorptive nonlinear optical material interacts with long pulse duration or high repetition rate laser pulses. It results in inaccurate characterization and reduction in efficiency of the nonlinear materials for device applications. In this article, the study investigates the influence of an external electric field on the thermal contribution to the nonlinear optical response of nitrobenzene (NB). Z‐scan measurements are performed on NB using 330 ps laser pulses at a wavelength of 532 nm with variable (10 Hz to 1 kHz) repetition rates. At low repetition rates, NB shows a positive nonlinear refractive index (+ n2), which leads to self‐focusing of the laser beam due to the optical Kerr effect. Cumulative thermal effects occur above a repetition rate of 200 Hz. At high repetition rates (>750 Hz), the sign of n2 becomes negative, implying a self‐defocusing behavior of the sample arising from the thermal‐induced nonlinear refractive index. By applying an external DC field to the NB, a reduction of the thermal contribution can be observed. At a sufficiently high electric field strength, the thermal contribution is suppressed and the inherent Kerr nonlinearity can be observed despite the high repetition rate of the pump laser.

Comparative Study of the Influence of Electric and Magnetic Fields on Tomato Germination Performance

Comparative Study of the Influence of Electric and Magnetic Fields on Tomato Germination Performance

The diffusion characteristics of POSS under electric field and non-uniform temperature field in natural ester insulating oil

The natural ester insulating oil is a green and environmentally friendly liquid dielectric, and nano additives can effectively improve its dielectric and heat transfer performance. However, nano additives are prone to agglomeration, especially under the influence of electric and temperature fields, which can impact the prolonged stable operation of power transformers. In this paper, the diffusion properties of caged Polysilsesquioxane (POSS) molecules in natural ester insulating oil under external electric field and non-uniform temperature field were investigated via simulation, and the effects of temperature and electric field on POSS molecules were expounded from the perspective of interaction. The results show that the high temperature difference and strong electric field can effectively improve the mobility of POSS molecules, and the temperature difference has a greater impact on the diffusion. The decrease of interaction energy is mainly due to the negative positive interaction between Si-O molecules in POSS molecules and insulating oil at high temperature, which counteracts the attraction of branch chains. At the same time, POSS molecules in the electric field will also show obvious polarization due to temperature changes, which further reduces the interaction between POSS molecules and insulating oil molecules. In addition, the electrostatic interaction energy decreases most obviously, which is the main reason that affects the migration characteristics of POSS molecules in natural ester insulating oil. This study provides a theoretical explanation for the migration mechanism of insulating oil in the microenvironment.

Pulsed Electric Field (PEF) and High-Power Ultrasound (HPU) in the Hurdle Concept for the Preservation of Antioxidant Bioactive Compounds of Strawberry Juice-A Chemometric Evaluation-Part I.

This work investigated the influence of pulsed electric field (PEF) and high-power ultrasound (HPU) combined with hurdle technology to preserve the bioactive compounds (BACs) content and antioxidant activity in stored strawberry juices. PEF was performed at 30 kV cm-1, 100 Hz during 1.5, 3, and 4.5 min, while HPU was performed at 25% amplitude and 50% pulse during 2.5, 5.0, and 7.5 min. Total phenols and hydroxycinnamic acids were the most stable BACs during the hurdle treatment without influence of the duration of both treatments, while flavonols and condensed tannins showed a significant stability dependence with respect to the duration of both treatments. Total phenols were also stable during storage, in contrast to the individual groups of BACs studied. A chemometric approach was used to optimize the parameters of the hurdle treatments with respect to the highest level of BACs and the antioxidant activity of the treated juices. In general, shorter treatment times in the hurdle approach resulted in better stability of BACs and antioxidant activity. The hurdle technology investigated in this study has the strong potential to be an excellent concept for optimizing the operating parameters of PEF and HPU technologies in the preservation of functional foods.

Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields

Importance of studying Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields lies in its relevance to fundamental physical phenomena, its applications in various fields of science and engineering and its potential for technological advancements. The study of Brinkman–Navier–Stokes flow under the influence of electric and magnetic fields, along with additional factors such as Joule heating, fractional derivatives and convection, represents a multifaceted and challenging problem in fluid dynamics and applied mathematics. In this study, we explore the combined effects of Joule heating due to electric current passing through the fluid and fractional derivatives that describe nonlocal behaviors. The fractional formulation leads to a relaxation mechanism that exhibits delay and recollection of the fluid motion. The organization of direct temperature and concentration changes in MHD flow is made possible by this formalization. A finite difference/finite element method is used to calculate the flow dynamics issue and fractionally linked fields. The physical factors explain how the topic under examination is relevant.

Enhanced cyclic stability and discharge capacity of NCM811 cathode by coating ferroelectric-type LiNbO3 ionically conductive layer

High nickel LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode is widely employed in power batteries. However, discharge capacity and cyclic stability are significantly influenced by the operating temperature. Surface coating is an effective way of improving the electrochemical properties of NCM811. Herein, a stable LiNbO3 coating layer, with excellent ferroelectricity, is introduced on the NCM811 surface. Several material and electrochemical characterization techniques, such as XRD, SEM, EDS, TEM, XPS, CV and EIS, are utilized to discuss the positive influence of LiNbO3 on electrochemical performance. On the one hand, LiNbO3 provides a protective layer to suppress side reactions and isolate the corrosion of electrolyte. On the other hand, ferroelectric LiNbO3 generates polarization under the influence of electric field to promote Li+ (de)intercalation during the charge/discharge process. Besides, LiNbO3 is a widely recognized fast ionic conductor that can promote the rapid diffusion of Li+. It is revealed that the LiNbO3-coated NCM811 exhibits excellent capacity retention of 91.7%, 93.5% and 88.4% at 0 ℃, 25 ℃ and 50 ℃ after 100 charge/discharge cycles at 1 C, respectively. Moreover, the initial discharge capacity of LiNbO3-coated NCM811 cathode is as high as 152.4 mAh/g at 0 ℃. These results indicate that a ferroelectric ionic conductor coating is an effective strategy to enhance the cyclic stability and specific capacity of NCM811 cathode.

Strong pyroelectric enhancement induced by the evolution of PNRs in paraelectric-phase KTN crystals

KTa1−xNbxO3 crystals exhibit excellent piezoelectric, ferroelectric, and electro-optical properties near the phase transition point, owing to the evolution of polar nanoregions (PNRs). This paper discusses the physical properties of the PNRs in three characteristic temperature ranges and analyzes the dielectric relaxation properties of the crystals. The effects of different heating rates and initial temperatures on the pyroelectric effect are discussed, and the influence of small electric fields on increasing the pyroelectric coefficient is investigated. The polarization characteristics of the crystal were obtained according to the change in the pyroelectric performance, and the influence of different conditions on the dynamic response of the PNRs was analyzed. It is proposed that the evolution of PNRs, induced by external coupling with an internal electric field, significantly affects macroscopic performance.

Numerical investigation of electroosmotic mixing in a contraction–expansion microchannel

Electroosmotic micromixing is generally a highly desirable technique in microanalysis systems due to its ability to mix fluids at the microliter level. Herein, a contraction-expansion microchannel is used to conduct a numerical study on the mixing caused by AC electroosmotic. We investigate the flow and concentration field distributions in the microchannel and observe two circulation flows and four rotating vortices generated in the expansion chamber by the influence of AC electric fields. The generation of the rotating vortex is highly dependent on the relative magnitudes of the electroosmotic force and inertia force. Higher inertial force prevents vortex formation and significantly reduces the mixing quality under higher inlet velocity. We also explore the influence of inlet velocity, frequency, and voltage on the vortex formation and mixing performance. The best mixing quality (0.997) is obtained at the inlet velocity of 0.2 mm/s with 0.1 V voltage in a 70 μm length-channel and the pressure drop is only 1.58 Pa. The current micromixer provides a favorable method of mixing fluid based on electroosmotic and could improve the mixing quality in microfluidic analysis devices.

The effect of electric field on the pyrolysis of transformer insulation oil–paper based on molecular dynamics

The regular operation of transformers is significantly impacted by the insulation effectiveness of the transformer insulation oil–paper. In order to explore the mechanism of the influence of an electric field on the thermal decomposition performance of insulating oil–paper, this paper simulated the process of electrothermal coupling decomposition of insulating oil–paper from the micro-level based on molecular dynamics. It was determined that the insulating oil is made up of three 16-carbon hydrocarbon molecules, while the insulating paper is made up of 30 fibrous disaccharide molecules. Using the molecular dynamics simulation approach, the pyrolysis of the insulating oil and insulating paper under various electric field strengths was simulated, and the lysis of reactants and the distribution of products were statistically examined. This paper also studied how the electric field affected the microscopic process of the insulating oil–paper pyrolysis. The findings demonstrate that under the influence of electrothermal coupling, the big molecules of the insulating oil and insulating paper are pyrolyzed to produce a variety of tiny molecules. For the insulating oil, it is easily subject to electron displacement polarization under the influence of an external electric field since it contains non-polar molecules, especially impacted by an electric field of 100 V/m. For the insulating paper, its polar nature, on the other hand, makes itself a good candidate for guiding polarization when exposed to an external electric field. So, the greater the electric field strength is, the greater the impact on the thermal decomposition of the insulating paper is.

Influence of electric field on the thermal properties of PP+NC nanocomposites for environmental chemistry application

Using Differential Thermal Analysis (DTA) method the thermal-physical properties of nanocomposites PP+NC for environmental and environmental chemistry applications were studied and the thermal-destruction processes after aging in an electric field were determined. The influence of various external factors (strong electric field, electric discharge, temperature, radiation, etc.) on polymers and composites based on polymers penetrates into the deep layers of the matrix and leads to the destruction and reconstruction of the structure. Changes in the ratio of crystalline and amorphous phase occur due to the formation of an interlayer crystalline phase in the matrix. In this regard, the thermal properties of pure PP and PP+2.0% NC nanocomposites were investigated using the derivatographic method to study the influence of the electric field on the aging process, melting temperature, and crystallization rate and depolymerization process.

Ultrasonic methods for the study of relaxation phenomena in dissipative media

In this work, a new method for study of the process of domain orientations and space charge relaxation in ferroelectrics using the surface acoustic waves (SAW) has been developed. The results of an experimental study of the dc electric field influence on the parameters of SAW propagation in piezoceramics with different ferroelectric "hardness" are presented.

Environmental Applications of Electromembrane Extraction: A Review.

Electromembrane extraction (EME) is a miniaturized extraction technique that has been widely used in recent years for the analysis and removal of pollutants in the environment. It is based on electrokinetic migration across a supported liquid membrane (SLM) under the influence of an external electrical field between two aqueous compartments. Based on the features of the SLM and the electrical field, EME offers quick extraction, effective sample clean-up, and good selectivity, and limits the amount of organic solvent used per sample to a few microliters. In this paper, the basic devices (membrane materials and types of organic solvents) and influencing factors of EME are first introduced, and the applications of EME in the analysis and removal of environmental inorganic ions and organic pollutants are systematically reviewed. An outlook on the future development of EME for environmental applications is also given.