Constructing Built-In Electric Fields with Semiconductor Junctions and Schottky Junctions Based on Mo-MXene/Mo-Metal Sulfides for Electromagnetic Response

The exploration of novel multivariate heterostructures has emerged as a pivotal strategy for developing high-performance electromagnetic wave(EMW)absorption materials.However,the loss mechanism in traditional heterostructures is relatively simple,guided by empirical observations,and is not monotonous.In this work,we presented a novel semiconductor-semiconductor-metal heterostructure sys-tem,Mo-MXene/Mo-metal sulfides(metal=Sn,Fe,Mn,Co,Ni,Zn,and Cu),including semiconductor junctions and Mott-Schottky junctions.By skillfully combining these distinct functional components(Mo-MXene,MoS_(2),metal sulfides),we can engineer a multiple heterogeneous interface with superior absorption capabilities,broad effective absorption bandwidths,and ultrathin matching thickness.The successful establishment of semiconductor-semiconductor-metal heterostructures gives rise to a built-in electric field that intensifies electron transfer,as confirmed by density functional theory,which collaborates with multiple dielectric polarization mechanisms to substantially amplify EMW absorption.We detailed a successful synthesis of a series of Mo-MXene/Mo-metal sulfides featuring both semiconductor-semiconductor and semiconductor-metal interfaces.The achievements were most pronounced in Mo-MXene/Mo-Sn sulfide,which achieved remarkable reflection loss values of-70.6 dB at a matching thickness of only 1.885 mm.Radar cross-section calculations indicate that these MXene/Mo-metal sulfides have tremendous potential in practical military stealth technology.This work marks a departure from conventional component design limitations and presents a novel pathway for the creation of advanced MXene-based composites with potent EMW absorption capabilities.

Superposition of dual electric fields in covalent organic frameworks for efficient photocatalytic hydrogen evolution

Covalent organic frameworks(COFs)are promising materials for converting solar energy into green hydrogen.However,limited charge separation and transport in COFs impede their application in the photocatalytic hydrogen evolution reaction(HER).In this study,the intrinsically tunable internal bond electric field(IBEF)at the imine bonds of COFs was manipulated to cooperate with the internal molecular electric field(IMEF)induced by the donor-acceptor(D-A)structure for an efficient HER.The aligned orientation of IBEF and IMEF resulted in a remarkable H_(2) evolution rate of 57.3 mmol·g^(-1)·h^(-1)on TNCA,which was approximately 520 times higher than that of TCNA(0.11 mmol·g^(-1)·h^(-1))with the opposing electric field orientation.The superposition of the dual electric fields enables the IBEF to function as an accelerating field for electron transfer,kinetically facilitat-ing the migration of photogenerated electrons from D to A.Furthermore,theoretical calculations indicate that the inhomogeneous charge distribution at the C and N atoms in TNCA not only pro-vides a strong driving force for carrier transfer but also effectively hinders the return of free elec-trons to the valence band,improving the utilization of photoelectrons.This strategy of fabricating dual electric fields in COFs offers a novel approach to designing photocatalysts for clean energy synthesis.

Effect of applied electric fields on supralinear dendritic integration of interneuron

Evidences show that electric fields(EFs)induced by the magnetic stimulation could modulates brain activities by regulating the excitability of GABAergic interneuron.However,it is still unclear how and why the EF-induced polarization affects the interneuron response as the interneuron receives NMDA synaptic inputs.Considering the key role of NMDA receptor-mediated supralinear dendritic integration in neuronal computations,we suppose that the applied EFs could functionally modulate interneurons’response via regulating dendritic integration.At first,we build a simplified multi-dendritic circuit model with inhomogeneous extracellular potentials,which characterizes the relationship among EF-induced spatial polarizations,dendritic integration,and somatic output.By performing model-based singular perturbation analysis,it is found that the equilibrium point of fast subsystem can be used to asymptotically depict the subthreshold input–output(sI/O)relationship of dendritic integration.It predicted that EF-induced strong depolarizations on the distal dendrites reduce the dendritic saturation output by reducing driving force of synaptic input,and it shifts the steep change of sI/O curve left by reducing stimulation threshold of triggering NMDA spike.Also,the EF modulation prefers the global dendritic integration with asymmetric scatter distribution of NMDA synapses.Furthermore,we identify the respective contribution of EF-regulated dendritic integration and EF-induced somatic polarization to an action potential generation and find that they have an antagonistic effect on AP generation due to the varied NMDA spike threshold under EF stimulation.

Oscillation of Dzyaloshinskii–Moriya interaction driven by weak electric fields

Dzyaloshinskii–Moriya interaction(DMI) is under extensive investigation considering its crucial status in chiral magnetic orders, such as Néel-type domain wall(DW) and skyrmions. It has been reported that the interfacial DMI originating from Rashba spin–orbit coupling(SOC) can be linearly tuned with strong external electric fields. In this work, we experimentally demonstrate that the strength of DMI exhibits rapid fluctuations, ranging from 10% to 30% of its original value, as a function of applied electric fields in Pt/Co/MgO heterostructures within the small field regime(< 10-2V/nm). Brillouin light scattering(BLS) experiments have been performed to measure DMI, and first-principles calculations show agreement with this observation, which can be explained by the variation in orbital hybridization at the Co/MgO interface in response to the weak electric fields. Our results on voltage control of DMI(VCDMI) suggest that research related to the voltage control of magnetic anisotropy for spin–orbit torque or the motion control of skyrmions might also have to consider the role of the external electric field on DMI as small voltages are generally used for the magnetoresistance detection.

Evaluation of genetic response of mesenchymal stem cells to nanosecond pulsed electric fields by whole transcriptome sequencing

BACKGROUND Mesenchymal stem cells(MSCs)modulated by various exogenous signals have been applied extensively in regenerative medicine research.Notably,nanosecond pulsed electric fields(nsPEFs),characterized by short duration and high strength,significantly influence cell phenotypes and regulate MSCs differentiation via multiple pathways.Consequently,we used transcriptomics to study changes in messenger RNA(mRNA),long noncoding RNA(lncRNA),microRNA(miRNA),and circular RNA expression during nsPEFs application.AIM To explore gene expression profiles and potential transcriptional regulatory mechanisms in MSCs pretreated with nsPEFs.METHODS The impact of nsPEFs on the MSCs transcriptome was investigated through whole transcriptome sequencing.MSCs were pretreated with 5-pulse nsPEFs(100 ns at 10 kV/cm,1 Hz),followed by total RNA isolation.Each transcript was normalized by fragments per kilobase per million.Fold change and difference significance were applied to screen the differentially expressed genes(DEGs).Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to elucidate gene functions,complemented by quantitative polymerase chain reaction verification.RESULTS In total,263 DEGs were discovered,with 92 upregulated and 171 downregulated.DEGs were predominantly enriched in epithelial cell proliferation,osteoblast differentiation,mesenchymal cell differentiation,nuclear division,and wound healing.Regarding cellular components,DEGs are primarily involved in condensed chromosome,chromosomal region,actin cytoskeleton,and kinetochore.From aspect of molecular functions,DEGs are mainly involved in glycosaminoglycan binding,integrin binding,nuclear steroid receptor activity,cytoskeletal motor activity,and steroid binding.Quantitative real-time polymerase chain reaction confirmed targeted transcript regulation.CONCLUSION Our systematic investigation of the wide-ranging transcriptional pattern modulated by nsPEFs revealed the differential expression of 263 mRNAs,2 miRNAs,and 65 lncRNAs.Our study demonstrates that nsPEFs may affect stem cells through several signaling pathways,which are involved in vesicular transport,calcium ion transport,cytoskeleton,and cell differentiation.

Two-dimensional investigation of characteristic parameters and their gradients for the self-generated electric and magnetic fields of laser-induced zirconium plasma

Two-dimensional diagnosis of laser-induced zirconium(Zr)plasma has been experimentally performed using the time-of-flight method by employing Faraday cups in addition to electric and magnetic probes.The characteristic parameters of laser-induced Zr plasma have been evaluated as a function of different laser irradiances ranging from 4.5 to 11.7 GW cm-2 at different axial positions of 1–4 cm with a fixed radial distance of 2 cm.A well-supporting correlation between the plume parameters and the laser-plasma-produced spontaneous electric and magnetic(E and B)fields was established.The measurements of the characteristic parameters and spontaneously induced fields were observed to have an increasing trend with the increasing laser irradiance.However,when increasing the spatial distance in both the axial and radial directions,the plasma parameters(electron/ion number density,temperature and kinetic energy)did not show either continuously increasing or decreasing trends due to various kinetic and dynamic processes during the spatial evolution of the plume.However,the E and B fields were observed to be always diffusing away from the target.The radial component of electron number densities remained higher than the axial number density component,whereas the axial ion number density at all laser irradiances and axial distances remained higher than the radial ion number density.The higher axial self-generated electric field(SGEF)values than radial SGEF values are correlated with the effective charge-separation mechanism of electrons and ions.The generation of a self-generated magnetic field is observed dominantly in the radial direction at increasing laser irradiance as compared to the axial one due to the deflection of fast-moving electrons and the persistence of two-electron temperature on the radial axis.

Applying Double Electric Fields to Avoid Deteriorating Movable Sensitive Parts in MEMS During Anodic Bonding

Anodic bonding between silicon and glass with dou bl e electric fields is presented.By this means,the damage caused by the electric f ield to the movable part during bonding can be avoided and the experiment result s show that.

Si_2O_2 molecule:structure of ground state and the excited properties under different external electric fields

Geometry and vibrational frequencies of the ground state of Si2O2 molecule are studied using density function theory （DFT） at the level of cc-pvtz and 6-311-k＋G^＊＊. It is found that the optimizing value by B31yp/cc-pvtz is closer to the experimental data. The excited properties under different external electric fields are also investigated by the time-dependent-DFT method. Transitions from the ground state of Si2O2 molecule to the first singlet state under different external electric fields can take place more easily. The corresponding absorption spectral line is about 360 nm in wavelength and the excitation energy is about 3.4 eV.

Electric fields inside and outside an anisotropic dielectric sphere

Analytical expressions of electric fields inside and outside an anisotropic dielectric sphere are presented by transforming an anisotropic medium into an isotropic one based on the multi-scale transformation of electromagnetic theory. The theoretical expressions are consistent with those in the literature. The inside electric field, the outside electric field and the angle between their directions are derived in detail. Numerical simulations show that the direction of the outside field influences the magnitude of the inside field, while the dielectric constant tensor greatly affects its direction.

Chemical Analysis of NO_x Removal Under Different Reduced Electric Fields

This work presents a chemical kinetic analysis of different species involved in nitrogen-oxygen mixed gas induced by stationary corona discharge at room temperature and atmospheric pressure.This study takes into account twenty different chemical species participating in one hundred and seventy selected chemical reactions.The reaction rate coefficients are taken from the literature,and the density is analyzed by the continuity equation without the diffusion term.A large number of investigations considered the removal of NOx showing the effects of N,O and O3 radicals.The aim of the present simulation is to complete these studies by analysing various plasma species under different reduced electric fields in the range of 100-200 Td（1 Td=10-21 V·m^2）.In particular,we analyze the time evolution of depopulation（10^-9-10^-3s）of NOx.We have found that the depopulation rate of NO and NO2 is substantially affected by the rise of reduced electric field as it grows from 100 Td to 200 Td.This allows us to ascertain the important role played by the reduced electric field.

Tumor ablation with nanosecond pulsed electric fields

Liver cancer is one of the most malignant cancers. It is reported that 600 000 patients died from liver cancer every year. [1,2] Hepatocellular carcinoma (HCC) is a particular problem because symptoms are not evident until the disease has progressed and hepatitis B, which is prominent specific regions of Asia, is a common precursor of the disease. There are many liver cancer

Effects of harmonic electric field frequency on electromagnetic and flow fields of Ti-Al melt in a rectangular mold based on numerical simulation

A model was established based on Maxwell's equations and Navier-Stokes' equations to numerically simulate the electromagnetic field and flow field in a rectangular mold with sectional aspect ratio of 5:1. The FEM (Finite Element Method) and APDL (ANSYS Parametric Design Language) were employed for the model to execute the modeling, meshing, load applying and solving. The Ti-Al alloy melt was selected to illustrate and validate the effects of the harmonic field frequency on the distribution of the physical fields in the mold. The simulated results demonstrate that with an increasing frequency the electric current forms an ellipsoid cavity where it becomes much weaker, and that the melt flows more intensely with low frequency (less than 5 kHz) than with high frequency (more than 5 kHz). The melt is pinched from the central part in the mold to bipolar parts in which it forms two vortexes in each side. The maximum value of fluid velocity exists near the bipolar zone.

Spiking patterns of a hippocampus model in electric fields

We develop a model of CA3 neurons embedded in a resistive array to mimic the effects of electric fields from a new perspective. Effects of DC and sinusoidal electric fields on firing patterns in CA3 neurons are investigated in this study. The firing patterns can be switched from no firing pattern to burst or from burst to fast periodic firing pattern with the increase of DC electric field intensity. It is also found that the firing activities are sensitive to the frequency and amplitude of the sinusoidal electric field. Different phase-locking states and chaotic firing regions are observed in the parameter space of frequency and amplitude. These findings are qualitatively in accordance with the results of relevant experimental and numerical studies. It is implied that the external or endogenous electric field can modulate the neural code in the brain. Furthermore, it is helpful to develop control strategies based on electric fields to control neural diseases such as epilepsy.

Design and Experiments of the High Voltage Pulsed Electric Fields Sterilization System

This experiment designed the pulsed electric fields （PEF） of high intensity of 100 kV· cm^-1 sterilization system. Fluorescent pseudomonas as target cell was operated 180 s in the PEF. By observing the difference of the bacteria before and after the disposal by TEM, it is found that the cell walls of the treated bacteria were broken. Irreversible perforations were formed on the cell membrane. The cell inclusions and cell fragments were leaked. The cell died as a result. The results showed that the PEF sterilization system designed can be used for liquid food sterilization experiments.

Coalescence behaviour of water droplets in water‐oil interface under pulsatile electric fields

In this research, the deformation of water droplets in sunflower oil-interface under pulsatile electric field was studied experimentally. Three types of coalescence were observed:(i) complete coalescence,(ii) incomplete coalescence and(iii) no-coalescence. The first type is desirable because of leaving no secondary droplets. The second type that produced secondary droplets which caused by necking process, due to extreme elongation of droplets(mostly small droplets), was undesirable; because the small droplets were more difficult to coalesce and remove. The no-coalescence was caused by very fast coalescence and extensive pushing of droplet into the continuous phase. In this work the process was operated with the utilization of a batch cylindrical separator with high voltage system. The lower part of the cylinder was filled with the aqueous phase and its top part was filled with sunflower oil to form an interface between the two phases. The effects of electric field strength,frequency, and waveform types were investigated. It was found that, the ramp-ac waveform was the best waveform, avoiding the production of secondary droplets and in this case the frequency also played an important role.

Currents and Electric Fields Induced in Anatomically Realistic Human Models by Extremely Low Frequency Electric Fields

There is increasing public concern about biological interactions with and the potential health effects of low frequency electric and magnetic fields. Recently, the ICNIRP （International Commission on Non-Ionizing Radiation Protection） has published new exposure guidelines with regard to these fields. The aim of this paper is to demonstrate the calculation of the currents and electric fields induced in the human body by external electric fields at 60 Hz, using numerical human models of anatomically-realistic human bodies, and to compare those results with the basic restrictions proposed by the new guidelines. As a result, in the case that a human is exposed to an electric field of 1 kV/m at 60 Hz the short-circuit current of 18 μA flows though the ankles. Furthermore, the electric field of 40 mV/m in the nervous tissue of the adult model is induced by exposure to external electric fields at the reference level, which is enough smaller than the basic restrictions established in the ICNIRP guidelines for occupational exposure.

Effects of vacancy and external electric field on the electronic properties of the MoSi_(2)N_(4)/graphene heterostructure

Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures.

Electrical fields and the promotion of endogenous angiogenesis in a rat spinal cord injury model

BACKGROUND： Previous studies have shown that direct current electrical fields affect development and growth of human microvascular endothelial cells, but the role of electrical fields on promoting angiogenesis in tissues following spinal cord injury remains poorly understood. OBJECTIVE： To determine the effects of electrical fields on angiogenesis and spinal cord repair following traumatic spinal cord injury in rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Chongqing Key Laboratory of Neurology, Affiliated Hospital of Chongqing Medical University, China from September 2007 to August 2008. MATERIALS： Hydrogen blood flow detector （Soochow University Medical Instrument, China）, Power Lab System （AD Instruments, Colorado Springs, CO, USA） and mouse anti-vascular endothelial growth factor （VEGF） monoclonal antibody （Sigma-Aldrich, St. Louis, MO, USA） were used in this study. METHODS： A total of 60 healthy, adult, Sprague Dawley rats were equally and randomly assigned to sham-surgery, model, and electrical field groups. The Allen＇s weight-drop method was used to induce complete spinal cord injury in the model and electrical field groups. Rats in the electrical field group were implanted with silver needles and electrical fields （350 V/m） were applied following traumatic injury. MAIN OUTCOME MEASURES： Latency of somatosensory-evoked potential was detected and spinal cord blood flow was measured by hydrogen blood flow detector. Microvascular density was determined by histological analysis. VEGF expression in the spinal cord was observed by immunohistochemical staining. RESULTS： Recovery of spinal cord blood flow was significantly increased in the electrical field group （at 1, 2, 4, 8, and 24 days after injury） compared with the model group （P 〈 0.05 or P 〈 0.01）. Latency of P1 waves in somatosensory-evoked potential of electrical field group （at 1,2, 4, 8, and 24 days after injury） was significantly shorter than the model group （P 〈 0.05 or P 〈 0.01）. Microvascular density and VEGF expression were greater in the electrical field group compared with the model group at 24 days after injury （P 〈 0.01）. CONCLUSION： Electrical fields （350 V/m） promoted angiogenesis within injured rat tissue following spinal cord injury and improved spinal cord function. Electrical fields could help to ameliorate spinal cord injury. The mechanisms of action could be related to increased VEGF expression.

Action potential-simulated weak electric fields can directly initiate myelination

BACKGROUND： Myelination is a process whereby glial cells identify, adhere, wrap and enclose axons to form a spiral myelin sheath. OBJECTIVE： To investigate the effects of action potential-simulated weak electric fields on myelination in the central nervous system. DESIGN AND SETTING： This single-sample observation study was performed at the 324 Hospital of Chinese PLA. MATERIALS： Two 5 μm carbon fibers were provided by the Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. One Sprague Dawley rat, aged 1 day, was used. METHODS： Cerebral cortex was harvested from the rat to prepare a suspension [（1 2）× 10^5/mL] containing neurons and glial cells. To simulate the axon, carbon fibers were placed at the bottom of the neuron-glial cell coculture dish, and were electrified with a single phase square wave current, 1×10^-2, 1×10^-3, 1×10^-4, and 1×10^-5 seconds, 1 Hz, 40 mV, and 10 μA, 30 minutes each, once a day for 10 consecutive days to simulate weak negative electric fields during action potential conduction. MAIN OUTCOME MEASURES： Glial cell growth and wrapping of carbon fibers were observed by phase contrast microscopy and immunohistochemistry. RESULTS： On culture day 7, cell groups were found to adhere to negative carbon fibers in the 1 × 10^-3 seconds square wave group. Cell membrane-like substances grew out of cell groups, wrapped the carbon fibers, and stretched to the ends of carbon fibers. Only some small and round cells close to negative carbon fibers were found on culture day 12. In the 1 × 10^-4 and 1 × 10^-3 seconds square wave groups, the negative carbon fibers were wrapped by oligodendrocytes or their progenitor cells. CONCLUSION： The local negative electric field which is generated by action potentials at 1×（10^-4-10^-3） seconds, 40 mV can directly initiate and participate in myelination in the central nervous system.

Binding energy of the donor impurities in GaAs-Ga_(1-x)Al_xAs quantum well wires with Morse potential in the presence of electric and magnetic fields

The behavior of a donor in the GaAs–GaAlAs quantum well wire represented by the Morse potential is examined within the framework of the effective-mass approximation. The donor binding energies are numerically calculated for with and without the electric and magnetic fields in order to show their influence on the binding energies. Moreover, how the donor binding energies change for the constant potential parameters(De, re, and a) as well as with the different values of the electric and magnetic field strengths is determined. It is found that the donor binding energy is highly dependent on the external electric and magnetic fields as well as parameters of the Morse potential.