Probing the electric double layer structure at nitrogen-doped graphite electrodes by constant-potential molecular dynamics simulations

Electric double layer(EDL)is a critical topic in electrochemistry and largely determines the working performance of lithium batteries.However,atomic insights into the EDL structures on heteroatom-modified graphite anodes and EDL evolution with electrode potential are very lacking.Herein,a constant-potential molecular dynamics(CPMD)method is proposed to probe the EDL structure under working conditions,taking N-doped graphite electrodes and carbonate electrolytes as an example.An interface model was developed,incorporating the electrode potential and atom electronegativities.As a result,an insightful atomic scenario for the EDL structure under varied electrode potentials has been established,which unveils the important role of doping sites in regulating both the EDL structures and the following electrochemical reactions at the atomic level.Specifically,the negatively charged N atoms repel the anions and adsorb Li~+at high and low potentials,respectively.Such preferential adsorption suggests that Ndoped graphite can promote Li~+desolvation and regulate the location of Li~+deposition.This CPMD method not only unveils the mysterious function of N-doping from the viewpoint of EDL at the atomic level but also applies to probe the interfacial structure on other complicated electrodes.

Failure evolution and disaster prediction of rock under uniaxial compression based on non-extensive statistical analysis of electric potential

Rock failure can cause serious geological disasters,and the non-extensive statistical features of electric potential(EP)are expected to provide valuable information for disaster prediction.In this paper,the uniaxial compression experiments with EP monitoring were carried out on fine sandstone,marble and granite samples under four displacement rates.The Tsallis entropy q value of EPs is used to analyze the selforganization evolution of rock failure.Then the influence of displacement rate and rock type on q value are explored by mineral structure and fracture modes.A self-organized critical prediction method with q value is proposed.The results show that the probability density function(PDF)of EPs follows the q-Gaussian distribution.The displacement rate is positively correlated with q value.With the displacement rate increasing,the fracture mode changes,the damage degree intensifies,and the microcrack network becomes denser.The influence of rock type on q value is related to the burst intensity of energy release and the crack fracture mode.The q value of EPs can be used as an effective prediction index for rock failure like b value of acoustic emission(AE).The results provide useful reference and method for the monitoring and early warning of geological disasters.

Gyrokinetic simulation of magnetic-island-induced electric potential vortex mode

Ion temperature gradient(ITG)-driven turbulence with embedded static magnetic islands is simulated by utilizing a gyrokinetic theory-based global turbulence transport code(GKNET)in this work.Different from the traditional equilibrium circular magnetic-surface average(EMSA)method,an advanced algorithm that calculates the perturbed magnetic-surface average(PMSA)of the electric potential has been developed to precisely deal with the zonal flow component in a non-circular magnetic surface perturbed by magnetic islands.Simulations show that the electric potential vortex structure inside islands induced by the magnetic islands is usually of odd parity when using the EMSA method.It is found that the odd symmetry vortex can transfer into an even one after a steep zonal flow gradient,i.e.the flow shear has been built in the vicinity of the magnetic islands by adopting the PMSA algorithm.The phase of the potential vortex in the poloidal cross section is coupled with the zonal flow shear.Such an electric potential vortex mode may be of essential importance in wide topics,such as the turbulence spreading across magnetic islands,neoclassical tearing mode physics,and also the interaction dynamics between the micro-turbulence and MHD activities.

Magnetic Field Curves and Magnetic Equipotential Surfaces around Crossing Electrical Wires Replacing Classical Magnetic Field Lines

This article is based on a recent model specifically defining magnetic field values around electrical wires. With this model, calculations of field around parallel wires were obtained. Now, this model is extended with the new concept of magnetic equipotential surface to magnetic field curves around crossing wires. Cases of single, double, and triple wires are described. Subsequent article will be conducted for more general scenarios where wires are neither infinite nor parallel.

Mitochondria–cGAS–STING axis is a potential therapeutic target for senescence-dependent inflammaging-associated neurodegeneration

The word “senescence” comes from the Latin senescens, meaning “to begin to age”, and is characterized by a long-lasting but reversible block in proliferation, resulting from stress-induced cell cycle arrest of previously replication-competent cells.

Recent Advances in Fibrous Materials for Hydroelectricity Generation

Depleting fossil energy sources and conventional polluting power generation pose a threat to sustainable development.Hydroelectricity generation from ubiquitous and spontaneous phase transitions between liquid and gaseous water has been considered a promising strategy for mitigating the energy crisis.Fibrous materials with unique flexibility,processability,multifunctionality,and practicability have been widely applied for fibrous materials-based hydroelectricity generation(FHG).In this review,the power generation mechanisms,design principles,and electricity enhancement factors of FHG are first introduced.Then,the fabrication strategies and characteristics of varied constructions including 1D fiber,1D yarn,2D fabric,2D membrane,3D fibrous framework,and 3D fibrous gel are demonstrated.Afterward,the advanced functions of FHG during water harvesting,proton dissociation,ion separation,and charge accumulation processes are analyzed in detail.Moreover,the potential applications including power supply,energy storage,electrical sensor,and information expression are also discussed.Finally,some existing challenges are considered and prospects for future development are sincerely proposed.

A model study of residual oil distribution jointly using crosswell and borehole-surface electric potential methods

Although high resolution can be provided by electrical logging, the measured electrical log range is narrow and is limited to near the well. Borehole-surface electric potential measurements are able to detect a wide enough range but its resolution is limited, particularly for reservoirs with complex oil and water distribution or complicated structure. In this study, we attempt to accurately locate the 3-D reservoir water and oil distribution by combining borehole-surface and crosswell electric potentials. First, the distributions of oil and water in both vertical and horizontal directions are detected by the borehole-surface and erosswell electric potential methods, respectively, and then the measured crosswell potential result is used to calibrate the measured borehole-surface electric potential data to improve vertical resolution so that the residual oil distribution is determined in a lower half-space with three dimensions. The evaluation of residual oil distribution is obtained by investigation of differences between the simulation results of the reservoir with and without water flooding. The finite difference numerical simulation results prove that the spatial residual oil distribution can be effectively determined by combining the crosswell and borehole-surface electric potentials.

Bimetallic In_(2)O_(3)/Bi_(2)O_(3) Catalysts Enable Highly Selective CO_(2) Electroreduction to Formate within Ultra-Broad Potential Windows

CO_(2)electrochemical reduction reaction(CO_(2)RR)to formate is a hopeful pathway for reducing CO_(2)and producing high-value chemicals,which needs highly selective catalysts with ultra-broad potential windows to meet the industrial demands.Herein,the nanorod-like bimetallic ln_(2)O_(3)/Bi_(2)O_(3)catalysts were successfully synthesized by pyrolysis of bimetallic InBi-MOF precursors.The abundant oxygen vacancies generated from the lattice mismatch of Bi_(2)O_(3)and ln_(2)O_(3)reduced the activation energy of CO_(2)to*CO_(2)·^(-)and improved the selectivity of*CO_(2)·^(-)to formate simultaneously.Meanwhile,the carbon skeleton derived from the pyrolysis of organic framework of InBi-MOF provided a conductive network to accelerate the electrons transmission.The catalyst exhibited an ultra-broad applied potential window of 1200 mV(from-0.4 to-1.6 V vs RHE),relativistic high Faradaic efficiency of formate(99.92%)and satisfactory stability after 30 h.The in situ FT-IR experiment and DFT calculation verified that the abundant oxygen vacancies on the surface of catalysts can easily absorb CO_(2)molecules,and oxygen vacancy path is dominant pathway.This work provides a convenient method to construct high-performance bimetallic catalysts for the industrial application of CO_(2)RR.

Mass Increase with Strong and Gravitational Potentials, and Mass Defect with Electromagnetic Potential

The proposal is “mass increases due to strong and gravitational potentials, while it decreases due to Electromagnetic potential”. This proposal explains the big difference in mass between hadrons (protons, neutrons, & mesons) and their components (quarks), mass difference between nucleus and its individual components (protons and neutrons), massless of gamma photons, abnormal masses of mesons and bosons, and the excess in galaxy masses (dark matter). Also, this proposal shows the exact relation between mass and energy: Strong Potential=−3.04mc2| Electric Potential |=−5.57×10−3mc2Gravitational Potential=−1.22×10−7mc2where m represents the excess in mass due to strong potential, or gravitational potential and represents the decrease in mass due to electromagnetic potential. Released energy here equals potential energy and doesn’t equal decrease in mass using the formula E = mc2. Released energy is transferred to heat, photons, kinetic energy… Finally, proposal will try to describe the relation between photon energy and mass of its components using the general equation of kinetic energy: Photon Energy=1/2mc2m is the sum of the individual masses of its components, while the total mass of photon is zero.

Efficient Metal Recovery from Industrial Wastewater:Potential Oscillation and Turbulence Mode for Electrochemical System

Efficient metal recovery from industrial wastewater facilitates addressing of the environmental hazards and resource requirements of heavy metals.The conventional electrodeposition recovery method is hampered by the limitations of interfacial ion transport in charge-transfer reactions,creating challenges for simultaneous rapid and high-quality metal recovery.Therefore,we proposed integrating a transient electric field(TE)and swirling flow(SF)to synchronously enhance bulk mass transfer and promote interfacial ion transport.We investigated the effects of the operation mode,transient frequency,and flow rate on metal recovery,enabling determination of the optimal operating conditions for rapid and efficient sequential recovery of Cu in TE&SF mode.These conditions included low and high electric levels of 0 and 4 V,a 50%duty cycle,1 kHz frequency,and 400 L·h^(-1)flow rate.The kinetic coefficients of TE&SF electrodeposition were 3.5-4.3 and 1.37-1.97 times that of single TE and SF electrodeposition,respectively.Simulating the deposition process under TE and SF conditions confirmed the efficient concurrence of interfacial ion transport and charge transfer under TE and SF synergy,which achieved rapid and highquality metal recovery.Therefore,the combined deposition strategy is considered an effective technique for reducing metal pollution and promoting resource recycling.

The Aharonov-Bohm Effect: An Exploration of Quantum Interference and Electromagnetic Potentials

The AB(Aharonov-Bohm)effect is a pivotal quantum mechanical phenomenon that illustrates the fundamental role of the electromagnetic vector potential A in determining the phase of a charged particle’s wave function,even in regions where the magnetic field B is zero.This effect demonstrates that quantum particles are influenced not only by the fields directly present but also by the potentials associated with those fields.In the AB effect,an electron beam is split into two paths,with one path encircling a solenoid and the other bypassing it.Despite the absence of a magnetic field in the regions traversed by the beams,the vector potential A associated with the magnetic flux Φ through the solenoid induces a phase shift in the electron’s wave function.This phase shift,quantified by △φ=qΦ/hc,manifests as a change in the interference pattern observed in the detection screen.The phenomenon underscores the principle of gauge invariance in QED(quantum electrodynamics),where physical observables remain invariant under local gauge transformations of the vector and scalar potentials.This reinforces the notion that the vector potential A has a profound impact on quantum systems,beyond its classical role.This article outlines the AB effect,including its theoretical framework,experimental observations,and implications.The focus on the role of the vector potential in quantum mechanics provides a comprehensive understanding of this important phenomenon.

The biofilm characteristics and enhanced performance of a marine microbial-electrolysis-cell-based biosensor under positive anodic potential

Microbial fuel cells have already been used as biosensors to monitor assimilable organic carbon(AOC).However,their signal production from AOC is known to be completely suppressed by dissoved oxygen(DO).In this study,two identical microbial electrolysis cell(MEC)based biosensors were inoculated with marine sediment and operated at two different anodic potentials,namely-300 mV and+250 mV relative to Ag/AgCl.The MEC biosensor operated under positive anodic potential conditions had electrochemically active microbial communities on the anode,including members of the Shewanellaceae,Pseudoalteromonadaceae,and Clostridiaceae families.However,the strictly anaerobic members of the Desulfuromonadaceae,Desulfobulbaceae and Desulfobacteraceae families were found only in the negative anodic potential MEC biosensor.The positive anodic potential MEC biosensor showed several other advantages as well,such as faster start-up,significantly higher maximum current production,fivefold improvement in the AOC detection limit,and tolerance of low dissolved oxygen,compared to those obtained from the negative anodic potential MEC biosensor.The developed positive anodic potential MEC biosensor can thus be used as a real-time and inexpensive detector of AOC concentrations in high saline and low DO seawater.

Electrical stimulation modulates injury potentials in rats after spinal cord injury

An injury potential is the direct current potential difference between the site of spinal cord injury and the healthy nerves. Its initial amplitude is a significant indicator of the severity of spinal cord injury, and many cations, such as sodium and calcium, account for the major portion of injury potentials. This injury potential, as wel as injury current, can be modulated by direct current field stimulation;however, the appropriate parameters of the electrical field are hard to define. In this paper, injury potential is used as a parameter to adjust the intensity of electrical stimulation. Injury potential could be modulated to slightly above 0 mV （as the anode-centered group） by placing the anodes at the site of the injured spinal cord and the cathodes at the rostral and caudal sections, or around-70 mV, which is resting membrane potential （as the cathode-centered group） by reversing the polarity of electrodes in the anode-centered group. In addition, rats receiving no electrical stimulation were used as the control group. Results showed that the absolute value of the injury potentials acquired after 30 minutes of electrical stimulation was higher than the control group rats and much lower than the initial absolute value, whether the anodes or the cathodes were placed at the site of injury. This phenomenon il ustrates that by changing the polarity of the electrical field, electrical stimulation can effectively modulate the injury potentials in rats after spinal cord injury. This is also beneficial for the spontaneous repair of the cel membrane and the reduction of cation influx.

Structural Surface Crack Monitoring Method Based on Electrical Potential Technique and Modern Surface Technology

Crack monitoring plays a great role in modern structural health monitoring, however, most of the conventional crack inspections have disadvantages in terms of the accuracy, expense, reliability, durability and level of instrumentation required. Thus, development of a simple and reliable crack inspection technique that allows continuous monitoring has been desired. In this paper, electrical potential technique and modern surface technology are employed together to develop a new structural surface crack monitoring method. A special crack monitoring coating sensor based on electrical potential technique was deposited on the hot spot of the structure by modern surface technology. The sensor consists of three layers： the isolated layer, the sensing layer and the protective layer. The isolated layer is prepared by anodic oxidation technology, the sensing layer is made of ion plated copper, and the protective layer is made of silicone. The thickness of each layer is at micrometer magnitude. The electrical conductivity of the sensor is very stable, and the fatigue performance of the specimen with or without coating sensor is nearly unchanged. The crack monitoring experiment result shows that there are two sudden rises of the coating sensor electrical potential values, corresponding to different stages of the crack initiation and propagation. Since the width of the surface coating sensor is only 0.5 mm, this crack monitoring sensor can detect the propagation of cracks less than 0.5 mm long. The method proposed takes the simplicity of electrical potential technique and can monitor surface crack of nearly all kinds of structures precisely. The results of this paper may form the basis of a new crack monitoring system.

Geometries and electronic structures of Zr_(n)Cu(n=2–12) clusters: A joint machine-learning potential density functional theory investigation

Zr-based amorphous alloys have attracted extensive attention because of their large glassy formation ability, wide supercooled liquid region, high elasticity, and unique mechanical strength induced by their icosahedral local structures.To determine the microstructures of Zr–Cu clusters, the stable and metastable geometry of Zr_(n)Cu(n=2–12) clusters are screened out via the CALYPSO method using machine-learning potentials, and then the electronic structures are investigated using density functional theory. The results show that the Zr_(n)Cu(n ≥ 3) clusters possess three-dimensional geometries, Zr_(n)Cu(n≥9) possess cage-like geometries, and the Zr_(12)Cu cluster has icosahedral geometry. The binding energy per atom gradually gets enlarged with the increase in the size of the clusters, and Zr_(n)Cu(n=5,7,9,12) have relatively better stability than their neighbors. The magnetic moment of most Zr_(n)Cu clusters is just 1μB, and the main components of the highest occupied molecular orbitals(HOMOs) in the Zr_(12)Cu cluster come from the Zr-d state. There are hardly any localized two-center bonds, and there are about 20 σ-type delocalized three-center bonds.

Investigation of fractured rock aquifer in South China using electrical resistivity tomography and self-potential methods

Assessment of fractured rock aquifers in many parts of the world is complicated given their strong heterogeneity. Delineation of the subsurface geological formation in the weathered terrain is essential for groundwater exploration. To achieve this goal, 2D electrical resistivity tomography(ERT) and self-potential(SP) in combination with joint profile method(JPM) and boreholes have been carried out to delineate the subsurface geological units, detect the fracture/fault zones in hard rock, monitor the groundwater flow, and estimate the groundwater reserves contained within the weathered terrain at a complex heterogeneous site of Huangbu, South Guangdong of China. The integration of resistivity images with the borehole lithology along three profiles delineates three subsurface distinct layers namely topsoil cover, weathered and unweathered layers. The incorporation of ERT and SP with JPM reveal five fractures/faults, i.e., F_1, F_2, F_3, F_4 and F_5. 2D ERT models interpret the less resistive anomalies as the fractures/faults zones, and high resistive anomalies as the fresh bedrock. The inversion program based on the smoothness-constraint is used on the resistivity field data to get more realistic three layered model. SP measurements are obtained along the same electrical profiles which provide the negative anomalies clearly indicating the groundwater preferential flow pathways along the fracture/fault zones. Hydraulic parameters namely hydraulic conductivity and transmissivity were determined to estimate the groundwater resources contained within the fractures/faults. The integrated results suggest that the fractures/faults zones are most appropriate places of drilling for groundwater exploration in the investigated area. Geophysical methods coupled with the upfront borehole data provides better understanding about the conceptual model of the subsurface geological formations. The current investigation demonstrates the importance of the integrated geophysical methods as a complementary approach for groundwater assessment in the hard rock weathered areas.

Molecular properties and potential energy function model of BH under external electric field

Using the density functional B3P86/cc-PV5Z method, the geometric structure of BH molecule under different external electric fields is optimized, and the bond lengths, dipole moments, vibration frequencies, and other physical properties parameters are obtained. On the basis of setting appropriate parameters, scanning single point energies are obtained by the same method and the potential energy curves under different external fields are also obtained. These results show that the physical property parameters and potential energy curves may change with external electric field, especially in the case of reverse direction electric field. The potential energy function without external electric field is fitted by Morse potential, and the fitting parameters are obtained which are in good agreement with experimental values. In order to obtain the critical dissociation electric parameter, the dipole approximation is adopted to construct a potential model fitting the corresponding potential energy curve of the external electric field. It is found that the fitted critical dissociation electric parameter is consistent with numerical calculation, so that the constructed model is reliable and accurate. These results will provide important theoretical and experimental reference for further studying the molecular spectrum, dynamics, and molecular cooling with Stark effect.

Study on the oscillating phenomena of electrical potential across a liquid membrane

The electrical oscillations across a liquid membrane in water/oil/water system was studied with octanol as oil phase by introducing two opposite charged surfactants in oil and aqueous phase, respectively. The sustained and rhythmic oscillation was observed. To a certain extent, the features of the oscillation （e.g. induction time, frequency, life time and orientation of the pulse pikes） strongly depend on the property of surfactant, dissolved in octanol. The mechanism may be explained by the formation and destruction of dual-ion surfactant membrane accompanying with emulsification at the interface and considering the coupling effect of diffusion and associated reaction in the vicinity of the interface.

Electric stimulation at sciatic nerve evokes long-term potentiation of cornu dorsale medullae spinalis field potential in rats at various developmental phases

BACKGROUND： Long-term potentiation of cornu dorsale medullae spinalis field potential in adult rats has already been reported; however, there is lack of correlated researches on naenonate, infant and adult rats which have different responses to pain conduction information.OBJECTIVE： To observe the various effects of electric stimulation at sciatic nerve on long-term potentiation of evoked field potential at superficial layer of cornu dorsale medullae spinalis of rats at various developmental phases and analyze manifestations of pain conduction information at superficial layers （ Ⅰ - Ⅱ）of cornu dorsale medullae spinalis in immature rats.DESIGN： Grouping controlled study.SETTING： Department of Physiology, Medical College of Wuhan University.MATERIALS： The experiment was carried out in the Laboratory of Physiology （provincial laboratory）,Medical College of Wuhan University from March 2006 to May 2007. A total of 27 healthy male Sprague-Dawley （SD） rats, 17- 90 days old, SPF grade, weighing 41 -200 g, were provided by Experimental Animal Center, Medical College of Wuhan University.METHODS： Based on their birthdays, rats were divided into naenonate group （17 - 20 days old, weighing 41-52 g, n =10）, infant group （35 - 50 days old, weighing 87 - 125 g, n =10） and adult group （60 - 90 days old, weighing 180 -200 g, n =7）. Left sciatic nerve was separated and stimulated with single square wave （15 V, 0.5 ms）. Meanwhile, evoked field potential was recorded at superficial layers of lateral T13 - L1 cornu dorsale medullae spinalis and then stimulated with high-frequent and high-intensive tetanizing current （30 -40 V, 0.5 ms, 100 Hz, 1s per bundle, 10s in bundle interval） four times. After the operation, onset of long-term potentiation was observed; meanwhile, amplitude changes and latency of field potential were analyzed.MAIN OUTCOME MEASURES： Amplitude and latency changes of field potential at superficial layers of cornu dorsale medullae spinalis of rats in the three groups.RESULTS： A total of 27 accepted rats were involved in the final analysis. ① Amplitude changes： Electric stimulation at sciatic nerve with high-frequent and high-intensive tetanizing current could induce evoked field potential at superficial layers （Ⅰ-Ⅱ ） of cornu dorsale medullae spinalis in the three groups.Long-term potentiation in the naenonate group manifested that amplitude of A-kind never fiber was raised and there was significant difference （P〈0.05）. In addition, average amplitude was increased and there was obviously significant difference （P〈0.01）. Long-term potentiation in the infant group manifested that amplitude of C-kind never fiber was raised and there was significant difference （P〈0.01）; while, long-term potentiation in the adult group manifested that amplitude of C-kind never fiber was raised and there was significant difference （P〈0.01）. Otherwise, latencies in the three groups were all shortened. ② Latency changes： Average latency of A-kind nerve fiber in the naenonate group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of C-kind nerve fiber was low and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation （P〉0.05）. Average latency of C-kind nerve fiber in the infant group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of A-kind nerve fiber was stable and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation （P〉0.05）. Average latency of C-kind nerve fiber in the adult group was shortened and there was significant difference （P〈0.01）; in addition, evoked potential of A-kind nerve fiber was stable and latency was immovable. There was no significant difference before and after high-frequent and high-intensive electric stimulation.CONCLUSION： Evoked field potential at superficial layer of comu dorsale medullae spinalis can be recorded through electric stimulation at sciatic nerve. Single stimulation and tetanizing electric stimulation can cause different characteristics of evoked field potential in rats at various developmental phases.Superficial layer of cornu dorsale medullae spinalis of naenonate rats is mainly caused by A-kind nerve fiber which participants in pain conduction and formation of pain sensitivity; however, that of infant and adult rats mainly depends on C-kind nerve fiber.

The Analytical Potential Energy Function of NH Radical Molecule in External Electric Field

The geometric structures of an Nit radical in different external electric fields are optimized by using the density functional B3P86/cc-PVSZ method, and the bond lengths, dipole moments, vibration frequencies and IR spectrum are obtained. The potential energy curves are gained by the CCSD （T） method with the same basis set. These results indicate that the physical property parameters and potential energy curves may change with the external electric field, especially in the reverse direction electric field. The potential energy function of zero field is fitted by the Morse potential, and the fitting parameters are in good accordance with the experimental data. The potential energy functions of different external electric fields are fitted adopting the constructed potential model. The fitted critical dissociation electric parameters are shown to be consistent with the numerical calculation, and the relative errors are only 0.27% and 6.61%, hence the constructed model is reliable and accurate. The present results provide an important reference for further study of the molecular spectrum, dynamics and molecular cooling with Stark effect.