Electric Force Research Articles

A photoelectrochemical sensor based on In2S3/AgInS2 in situ Z-type heterojunction with “photo-modulated interface charge” for sensitive detection of Programmed Death-Ligand 1

The construction of heterostructure photoelectrodes can enhance the performance of photoelectrochemical (PEC) sensors. However, it is still a critical challenge to achieve efficient transfer of interface carriers. In this paper, we propose a strategy of “photo-modulated interface charge” to design a PEC sensor based on a hollow hexagonal tubular In2S3/AgInS2 in situ Z-type heterojunction for the susceptible detection of Programmed Death-ligand 1 (PD-L1). The hollow structured In2S3/AgInS2 is ingeniously synthesized employing indium-sourced MIL-68 as a sacrificial template and in situ cation exchange technique. This composite material has close contact interfaces due to in situ growth, which facilitates the spontaneous establishment of a robust and stable built-in electric field between the interfaces. Moreover, the inner cavity structure promotes multiple light refractions and scatterings, significantly enhancing light trapping capability. Under the influence of both light irradiation and electric field force, the migration direction of the interfacial charge is reversed, forming a Z-transfer path, which effectively delays the compounding of the electron-hole pairs (e-/h+) and further improves the sensitivity of the sensor. The minimum detection threshold of the PEC sensor is 26.58 fg/mL, and the feasibility of real samples is investigated, providing new insights for early diagnosis and prognostic treatment of diseases.

Numerical study on the efficiency of an electrostatic precipitator having the shape of a truncated cone

This paper presents a comprehensive numerical study of a truncated conical precipitator. The main objective was to enhance the efficiency of the precipitator by exploring the influence of several parameters on particle trajectories and the evolution of the collection efficiency. The studied parameters include the cone coefficient ( D), flow velocity, applied voltage, conduit diameter and length, as well as relative permeability. For each parameter, analyses were conducted on the evolution of the collection efficiency for particles with various diameters, ranging from 0.01 to 10 μm. The results obtained from the numerical simulation on COMSOL Multiphysics® indicate that, regardless of the value of D, the precipitator exhibits optimal efficiency in collecting particles with extreme diameters (0.01 and 10 μm) due to the dominance of the electrical force. In contrast, particles with intermediate diameters (0.1–1 μm) present a challenge, as the drag and electric forces are too weak to ensure effective particle collection. The study highlights that a sharper tip at the top of the precipitator significantly enhances its efficiency. Increasing the applied voltage and selecting lower inner radii of the collecting electrode reinforce the electrical force and enhance particle collection. Furthermore, increasing the height of the precipitator directs particle trajectories more effectively toward the collecting electrode. The results provide valuable insights for the design of more efficient precipitators and propose practical guidelines for improving their effectiveness. These contributions are particularly important for air pollution control technologies, offering significant advancements in this field.

The formation process and mechanism of coaxial electrostatic atomization of nanofluid oil film droplets

Abstract In coaxial electrostatic atomization cutting, the atomization effect of nanofluid oil film droplets directly affects the cooling and lubrication performance. To further understand the formation process of tiny oil film water droplets in coaxial electrostatic atomization, this paper takes LB2000/water, LB2000/0.1 vol.% graphite water-based nanofluids, LB2000/0.3 vol.% graphite water-based nanofluids, LB2000/0.5 vol.% graphite water-based nanofluids as the research object. Coaxial electrostatic atomization simulation is carried out based on the determined common voltage of the conical jet (-6.5 kV). The formation process of nanofluid oil film water droplets was analyzed using electric field force, charge concentration, and volume force, and the droplet states under different fluid types were compared. The results show that when nanoparticles are added to the inner fluid, the charge concentration increases, the electric field force and volume increase, and the formation speed of the cone jet increases significantly.

Lattice Boltzmann study of droplet dynamic behaviors impinging on textured surfaces under an external electric field

Textured surfaces contribute to enhancing the cooling effectiveness of electrostatic spray, while the droplet impacting dynamics on such substrates under the influence of electric field are crucial for cooling efficiency. This study utilized a multiphase lattice Boltzmann method combined with the leaky dielectric model to systematically examine the dynamics of droplet impingement on textured surfaces when exposed to electric field. The impact of Weber number, microstructural surface parameters, and electric field strength on droplet impact behavior was discussed in detail. Simulation outcomes reveal that, without the presence of an electric field, the impingement of droplets on textured surfaces results in three distinct deposition states: the Cassie state, partial penetration state, and Wenzel state, primarily contingent upon the surface solid fraction and the droplet impingement velocity. In the Cassie impact regime influenced by an applied electric field, the droplet spreading behaviors exhibit minimal sensitivity to the electric field, with surface tension and inertia primarily governing the spreading dynamics. Throughout the retraction stage, the droplet elongated the direction of the electric field as a result of electric field forces, and eventually, as the electric field strength grows, it bounces off the surface. In the Wenzel impact regime, as the strength of the electric field escalates, the droplet undergoes upward stretching and splits into satellite droplets during the retraction phase, attributed to the dynamic pressure and electrostatic pressure at the apex exceeding the capillary pressure and gravity. These findings could aid in advancing electrostatic spray cooling technology.

Robust control of charged particles position in a homogeneous isotropic turbulence using an electric field

This research investigates the position control of spherical charged particles suspended in a directly simulated homogeneous isotropic turbulence, which has the potential to improve the efficiency of the electrostatic precipitators (ESPs) in removing gaseous pollutants. To do this, the electric field used in ESPs is controlled by the sliding mode control method to steer the particles toward their desired positions. The particles are charged using the field charging method, which leads to electrical interactions between them. Employing the linked-list method reduces the computational cost related to these interaction forces. The dynamics of particles is simulated using the Maxey–Riley equation including the control force. Coupling the direct numerical simulation solver with the proposed control method and the linked-list scheme, along with solving the particle dynamics, complicates the problem from a control theory point of view. The robustness of the proposed model-free control method leads to overcoming disturbances and uncertainties in the simulation due to turbulence and repulsive electric forces. Hence, steering a large number of charged particles to places with more pollution concentration or increasing the duration of exposure of the particles to gaseous pollutants becomes possible. The findings of the present research are pertinent to improving the performance of air purification equipment.

Discharge and mass transfer characteristics of atmospheric pressure gas-solid two-phase gliding arc

In this work, a gas-solid two-phase gliding arc discharge (GS-GAD) reactor was built. Gliding arc was formed in the gap between the blade electrodes, and solid powder was deposited on the sieve plate positioned beneath the blade electrodes. A range of experimental parameters, including the inter-electrode spacing, gas flow rate, applied voltage, and the type of the powder, were systematically varied to elucidate the influence of solid powder matter on the dynamics of gliding arc discharge (GAD). The discharge images were captured by ICCD and digital camera to investigate the mass transfer characteristics of GS-GAD, and the electrical parameters, such as the effective values of voltage, current, and discharge power were record to reveal the discharge characteristics of GS-GAD. The results demonstrate that powder undergoes spontaneous movement towards the upper region of the gliding arc due to the influence of electric field force. Increasing the discharge voltage, decreasing relative dielectric constant of the powder and reducing the electrode-to-sieve-plate distance all contribute to a greater involvement of powder in the GAD process, subsequently resulting in an enhanced powder concentration within the GAD region. Additionally, powder located beneath the gliding arc experiences downward resistance caused by the opposing gas flow and arc. Excessive gas flow rate notably hampers the powder concentration within the discharge region, and the velocity of powder motion in the upper part of the GAD region is reduced. Under the condition of electrode-to-sieve-plate distance of 30 mm, gas flow rate of 1.5 L/min, and peak-to-peak voltage of 31 kV, the best combination of arc gliding and powder spark discharge phenomena can be achieved with the addition of Al2O3 powder.

Local Electric Field Accelerates Zn2+ Diffusion Kinetics for Zn‐V Battery

AbstractVanadium‐based aqueous zinc‐ion batteries (AZIBs) exhibit significant potential for large‐scale energy storage applications, attributed to their inherent safety characteristics. Addressing the slow transport kinetics of divalent Zn2+ within the cathode lattice, thereby enhancing the rate capability and stability, is essential for the Zn‐V battery system. In this study, a local electric field (LEF) strategy is introduced to accelerate the Zn2+ diffusion by creating abundant oxygen vacancies (Ov) in V2O5. Comprehensive characterization and density functional theory (DFT) calculations reveal the formation of the Ov induced atomic‐level donor‐acceptor couple configuration, verify and visualize the LEF. The fabricated LEF‐enhanced vanadium oxide (LEF‐VO) exhibits exceptional rate capability, achieving 338.3 mA h g−1 at a current density of 10 A g−1, and maintaining 66.4% of its capacity over a range from 0.2 to 20 A g−1. Furthermore, the influence of the LEF on expediting Zn2+ diffusion kinetics is elucidated, correlating to the electrical force. This novel LEF approach offers valuable insights for advancing high‐rate cathode materials.

Evidence of stretching/moving sheet-triggered nonlinear similarity flows: atomization and electrospinning with/without air resistance

PurposeThe purpose of this study is two-fold. First, it aims to differentiate the response of a stretching jet encountering a quadratic air resistance from the classical jet shape formed in a frictionless medium. Second, it investigates how the resulting jet forms with and without air resistance, seeking evidence that supports the similarity flows frequently studied for stretching/moving thin bodies under the boundary layer approximation.Design/methodology/approachThis study extends the established electrohydrodynamic stretching jet theory, used to model electrospinning or jet printing in the absence of air resistance, to encompass the impact of the retarding force on the jet stretching in both the cone and final regimes before it impinges on a substrate.FindingsA close examination of the nonlinear governing equations reveals that the jet rapidly thins near the nozzle because of the combined action of viscous and electrical forces. In this region, the exponentially decaying jet receives further support from the air resistance, resulting in a closer alignment with the observed experimental jet. This exponential decay, accelerated by the inversely quadratic speed of the liquid particles, serves as clear evidence for the existence of a similarity flow over an exponentially stretching sheet. Furthermore, in the final regime, the jet stretching exhibits an algebraic decay in the absence of air friction, while with air resistance, it decays exponentially to reach a limiting speed. In the former case, a square root dependence of the stretching jet speed leads to the emergence of a similarity flow over a thin stretching jet, while in the latter case, a Sakiadis’ similarity flow appears over a continuously moving flat surface.Practical implicationsThe analysis goes beyond jet hydrodynamics, delving into the interplay of electrostatic forces (including Coulomb’s law) and quadratic air drag, drawing upon experimental data on glycerol liquid presented in earlier publications.Originality/valueFinally, the asymptotic behavior of the stretching jet under the combined influence of electrostatic pull and its electric currents because of bulk conduction and surface convection is validated through a comprehensive numerical simulation of the nonlinear system.

Double emulsion generation in shear-thinning fluids under electric field effects

Double emulsions are encapsulated microstructures with medical, food, and cosmetics applications. Precise control over their parameters, such as volume, thickness, and size distribution, is crucial. This study numerically investigates, for the first time, the generation of double emulsions in a shear-thinning outer fluid under the influence of an external DC electric field. A dual co-flowing microfluidic device is chosen as the flow domain, and the shear-thinning behavior of the outer fluid is approximated by the Carreau–Yasuda rheological model. The governing equations are discretized on structured numerical grids using the VOF-CSF model and the finite volume method. The combined effects of the shear-thinning behavior and electric forces on compound droplet formation parameters, including volume, eccentricity, maximum thickness, and jet length, are studied carefully. Results show that for highly shear-thinning fluids, the application of electric forces can ensure the generation of desired compound droplets, which is not feasible without electric field effects. However, excessive electric forces can disrupt the droplet generation process, especially for moderate to low shear-thinning fluids. These findings provide new insights into the role of external electric fields in double emulsion generation and highlight their potential to optimize the production process.

Energy transfer, conversion and mechanical regulation in graded piezoelectric semiconductor bipolar junction transistor

While the effective regulation of carrier redistribution in piezoelectric semiconductor devices by mechanical loads through piezoelectric polarized electric fields is well-studied, there is a scarcity of reported research on the influence of energy transfer and conversion characteristics in a non-thermal equilibrium state of these devices. This paper establishes a nonlinear multi-field coupling model for piezoelectric semiconductor graded bipolar junction transistor (PS-GBJT) and proposes a corresponding multi-gradient iterative algorithm. We regard the product of current and built-in electric field as the work done by electric field force on carriers. By incorporating the energy absorbed/released during carrier recombination/generation process, we observe that non-equilibrium carriers act as a medium that facilitates energy conversion between these two mechanisms. Additionally, the non-uniformly distributed doping extends the influence of space charge region throughout entire transistor. In terms of external input electrical energy, the emitter, base, and collector regions play roles of input energy, transfer energy, and output energy, respectively. The study concludes by demonstrating the regulation of energy transfer or conversion efficiency in emitter, base, and collector regions through mechanical loads, thereby altering the heating behavior of entire GBJT and reshaping its energy transfer path. This leads to the significant finding that distinct energy transfer paths fundamentally define the various operational states of GBJT. The novel insights gained from this research hold reference value for thermal design and energy management of electronic devices.

An insight into physicochemical properties of hexagonal lyotropic liquid crystal templates from amphiphiles for mesoporous structural administration

Hexagonal lyotropic liquid crystals (HLLC) provide an ideal template for the fabrication of nanofiltration membranes without the flux-selectivity trade-off problem. Amphiphiles, the core components of the columnar micelles in the HLLC system, play a key role in regulating the nanostructure, their effects on dimensional stability and physicochemical properties of the system however have not been explored well. In this research, we compared the dimensional stability and physicochemical properties of HLLC templates prepared from amphiphiles with various head groups and tail lengths. The amphiphiles with charged head groups (dodecyl trimethylammonium bromide, DTAB, and hexadecyl trimethylammonium bromide, CTAB) enable more monomers to be introduced and a much smaller (∼ 1/2) pore size than that with uncharged ones (polyethylene glycol hexadecyl ether, Brij56). The tail length however mainly regulates the width of water channels with CTAB being 23.27 Å and DTAB about 17.06 Å when the head groups are identical. Although the HLLC systems with CTAB and DTAB present a little bit higher phase transition temperature, the dynamic mechanical stability is much better than that with Brij56 at room temperature, facilitating the reorientation process under an electric force with the order parameter reaching to about 0.9 and the retention of the aligned nanostructure with the absence of the force at room temperature. The study enables a better understanding of the effects of amphiphiles on HLLC templates and their tunability for advanced nanofiltration membranes.

Study on the preparation and fretting behavior of bonded oriented MoS2 solid lubricant coating

The bonded MoS2 solid lubricant coating is an effective measure to mitigate the fretting wear of AISI 1045 steel. In this work, the amino functionalized MoS2 was protonated with acetic acid to make the MoS2 positively charged. The directional arrangement of protonated MoS2 in the coating was achieved by electrophoretic deposition under the electric field force. The bonded directionally aligned MoS2 solid lubricant coating showed high adaptability to various loads and excellent lubrication performance under all three working conditions. At a load of 10 N, the friction coefficient and wear volume of the coating with 5 wt% protonated MoS2 decreased by 20.0% and 37.2% compared to the pure epoxy coating, respectively, and by 0.07% and 16.8% than the randomly arranged MoS2 sample, respectively. The remarkable lubricating properties of MoS2 with directional alignment were attributed to its effective load-bearing and mechanical support, barrier effect on longitudinal extension of cracks, and the formation of a continuous and uniform transfer film.

Dynamic Characteristics of λ-DNA Molecules Translocating through Tapered Microfluidic Channel System Driven by Electric Field Force

Dynamic Characteristics of λ-DNA Molecules Translocating through Tapered Microfluidic Channel System Driven by Electric Field Force

Analysis of Transformer GSB Bushing Fault Causes Based on Finite Element Simulation

Abstract In response to a sudden explosion and fire fault during the operation of a GSB dry-type transformer bushing in a certain power grid company, based on the structural parameters of the bushing measured by the supplier and on-site, a reverse design of the capacitor core was carried out on the faulty bushing. Based on the measured parameters and reverse design results, a finite element simulation model of the bushing electric field and structural force field was established. Calculate the electric field distribution of the casing under normal operation, 60s power frequency withstand voltage, lightning impulse, operation impulse, and other operating conditions; Conduct finite element simulation of structural mechanics to calculate the stress distribution of the casing under conditions such as cantilever load and short circuit impact; Based on the discharge traces discovered during disassembly, simulation calculations were conducted by assuming the defect situation of the casing, and the electric field distribution of the casing under different defect types was quantitatively analyzed. The simulation calculation results of the electric field under various working conditions have verified that the occurrence of this fault is the result of multiple defects working together, providing quantitative support for fault analysis and providing a certain reference for the operation and maintenance of similar casings.

Radial and Vertical Structures of Plasma Disk in Jupiter's Middle Magnetosphere

AbstractThe Juno mission flew through the plasma disk near the equator in Jupiter's magnetosphere frequently. We identify 274 plasma disk crossings of Juno between 10 and 40 RJ from PJ5 to PJ44. Using a forward modeling method that combines the JADE‐I time‐of‐flight and SPECIES data sets, we perform a survey of ion properties in the plasma disk. Ions are heated from 1.5 to 6 keV between 15 and 30 RJ. Density and temperature are locally anti‐correlated. Assumed to be related to centrifugal instabilities, cold, dense plasma are commonly observed near midnight. Plasma corotates around Jupiter and the rigid corotation breaks down outside 15–20 RJ. The plasma bulk velocity increases from the post‐dusk sector to the pre‐dawn sector featuring injection flows in the pre‐dawn sector, which is consistent with the Vasyliunas cycle. Strong outflows (>100 km/s) are commonly observed outside 20 RJ and the average radial velocity increases with radial distance. The ion abundance changes between 10 and 18 RJ and that might indicate plasma sources and/or sinks near Europa and Ganymede. The vertical distribution of ions is controlled by the balance between centrifugal, pressure gradient, and ambipolar electric field forces. An example near the M‐shell of 13.5 shows that average plasma temperature increases by a factor of 10 from the disk center to edge, because cold ions are more confined near the equator. Lighter ions with higher charge states have more mobility along the field line and have larger scale heights. The observations are compared with multi‐species diffusive equilibrium model.

Liquid-to-gas transfer of sodium in a liquid cathode glow discharge

Plasma-liquid interactions have been extensively studied with a focus on the transport of reactive species from the plasma to the liquid phase and their induced liquid phase chemistry and resulting applications. While solute transfer from the liquid to the gas phase in plasmas has been widely used in analytical chemistry, the underlying processes remain relatively unexplored. We report spatially and temporally resolved absolute density measurements of sodium in a plasma with a NaCl solution cathode using two-photon absorption laser induced fluorescence (TaLIF). The observed non-linear increase in sodium density with solution conductivity is shown to correlate with droplet generation as visualized by Mie scattering. The findings are explained by droplet generation by electrospray induced by Taylor cone formation as underpinning mechanism for the introduction of sodium in the plasma. An analytical sheath model combined with a scaling law shows an increase in electric field force with solution conductivity that is consistent with the observed non-linear increase in sodium density in the plasma with solution conductivity.

A novel electric field-assisted material extrusion process for clean additive manufacturing

Material extrusion (MEX) is a type of additive manufacturing technique that is widely used in a variety of applications. However, the issue of reduced quality of printed parts caused by degraded polymer debris accumulation on the nozzle surface during the MEX process has received very limited attention. This work presents a novel electric field-assisted MEX (E-MEX) method to solve the quality issue by significantly reducing the accumulations of polymer debris on the nozzle. By applying a high-voltage power source between the nozzle and the build plate, an electrostatic force was generated to overcome the which showed great potential to reduce the accumulation of molten thermoplastic material on the nozzles. Both the E-MEX and conventional MEX methods were used to print test specimens for specific amounts of time to confirm the efficacy of the E-MEX method. 3D scanning was used to quantify the volumes of debris that had accumulated on the nozzle. Compared to the conventional MEX method, the E-MEX printing reduced debris accumulation by 47 % after about 5 h and over 80 % after about 15 h of the printing process. The changes in electric field intensity over orienting height were analyzed using numerical simulations. The relationship between electric field intensity and time spent by the nozzle during the printing process at a specific height was established. The polymer accumulation in the E-MEX process was found to be dependent on the electric field intensity and the continuous time spent by the nozzle in the weaker electric field enhanced polymer debris accumulations on the nozzle surfaces. The presented study integrates experimental observations with simulation results, revealing the mechanism of debris accumulation on the nozzle when the electric field decreased to a certain level during printing process. A numerical simulation model was developed to understand the traveling of accumulated polymer debris from the nozzle's outer surface to the printing layer under the influence of electrostatic force. The simulation results showed that the dragging of polymer debris towards the build plate occurs when the electric force acting in the tangential and normal direction is sufficient to overcome the viscous force and normal force in the polymer debris. The simulation results also showed some part of the debris remained in the crease area of the nozzle surface due to the viscous and surface tension forces prevailing over the electric force.

Mechanism of Antiferroelectricity in Polycrystalline ZrO2

AbstractThe size and electric field dependent induction of polarization in antiferroelectric ZrO2 is the key to several technological applications that are unimaginable a decade ago. However, the lack of a deeper understanding of the mechanism hinders progress. Molecular dynamics simulations of polycrystalline ZrO2, based on machine‐learned interatomic forces with near ab initio quality, shed light on the fundamental mechanism of the size effect on the transition fields. Stress in the oxygen sublattice is the most important factor. The so constructed interatomic forces allow the calculation of the transition fields as a function of the ZrO2 film thickness and predict the ferroelectricity at large thickness. The simulation results are validated with electrical and piezo response force microscopy measurements. The results allow a clear interpretation of the properties of the double‐hysteresis loops as well as the construction of the free energy landscape of ZrO2 grains.

Impact of proton radiation on Zr-doped HfO2-based ferroelectric memory

HfO2-based ferroelectric random access memory (FeRAM) has attracted tremendous attention in the field of data storage. However, the radiation performance and tolerance of FeRAM have not been investigated comprehensively. In this work, the electrical and structural properties of the W/TiN/Zr-doped HfO2(HZO)/TiN ferroelectric memory after radiation by 5 MeV proton at room temperature (RT) and low temperature (LT) were studied. After performing electrical and piezoresponse force microscopy (PFM) characterization, it was demonstrated that the radiation effect of HZO MFM ferroelectric memory strongly depends on the radiation temperature. The dielectric constant (Ɛr) and the remanent polarization (2Pr) values of the capacitor first decreased and then increased with the increasing of fluence at RT. Once the HZO thin film was radiated by protons at extremely low temperature, the performance of the HZO memory would be completely degraded. The increased ferroelectric properties due to RT radiation will be partially weakened after annealing at room temperature. The ferroelectric properties of the samples radiated by LT proton radiation would be restored due to the domain unpinning effect.

Study on the mesoscopic dynamic effects of tumor treating fields on cell tubulin

Tumor treatment fields (TTFields) can effectively inhibit the proliferation of tumor cells, but its mechanism remains exclusive. The destruction of cellular microtubule structure caused by TTFields through electric field force is considered to be the main reason for inhibiting tumor cell proliferation. However, the validity of this hypothesis still lacks exploration at the mesoscopic level. Therefore, in this study, we built force models for tubulins subjected to TTFields, based on the physical and electrical properties of tubulin molecules. We theoretically analyzed and simulated the dynamic effects of electric field force and torque on tubulin monomer polymerization, as well as the alignment and orientation of α/β tubulin heterodimer, respectively. Research results indicate that the interference of electric field force induced by TTFields on tubulin monomer is notably weaker than the inherent electrostatic binding force among tubulin monomers. Additionally, the electric field torque generated by the TTFileds on α/β tubulin dimers is also difficult to affect their random alignment. Therefore, at the mesoscale, our study affirms that TTFields are improbable to destabilize cellular microtubule structures via electric field dynamics effects. These results challenge the traditional view that TTFields destroy the microtubule structure of cells through TTFields electric field force, and proposes a new approach that should pay more attention to the "non-mechanical" effects of TTFields in the study of TTFields mechanism. This study can provide reliable theoretical basis and inspire new research directions for revealing the mesoscopic bioelectrical mechanism of TTFields.