Variation of Two-photon Absorption Cross Sections and Optical Limiting of Compounds Induced by Static Electric Field

By numerically solving the Maxwell-Bloch equations using an iterative predictor-corrector finite-difference time-domain technique, we investigate propagating properties of a few-cycle laser pulse in a 4,4＇-bis（di-n-butylamino） stilbene （BDBAS） molecular medium when a static electric field exists. Dynamical two-photon absorption （TPA） cross sections are obtained and optical limiting （OL） behavior is displayed. The results show that when the static electric field intensity increases, the dynamical TPA cross section is enhanced and the OL behavior is improved. Moreover, both even- and odd-order harmonic spectral components are generated with existence of the static electric field because it breaks the inversion symmetry of the BDBAS molecule. This work provides a method to modulate the nonlinear optical properties of the BDBAS compounds.

Saturated sodium chloride solution under an external static electric field: A molecular dynamics study

The behavior of saturated aqueous Na Cl solutions under a constant external electric field（E） was studied by molecular dynamics（MD） simulation. Our dynamic MD simulations indicated that the irreversible nucleation process towards crystallization is accelerated by a moderate E but retarded or even prohibited under a stronger E, which can be understood by the competition between self-diffusion and drift motion. The former increases with E, thereby accelerating the nucleation process, whereas the latter pulls oppositely charged ions apart under a stronger E, thereby decelerating nucleation.Additionally, our steady-state MD simulations indicated that a first-order phase transition occurs in saturated solutions at a certain threshold Ec. The magnitude of Ec increases with concentration because larger clusters form more easily when the solution is more concentrated and require a stronger E to dissociate.

Effects of direct current electric field on corrosion behaviour of copper, Cl- ion migration behaviour and dendrites growth under thin electrolyte layer

Effect of direct current electric field （DCEF） on corrosion behaviour of copper printed circuit board （PCB-Cu）, Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy （SEM） with energy dispersive spectrometer （EDS）. Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively.

Research on the Static Magnetic Field of Ships with Corrosion and Anticorrosion Efficacy Using Electric Dipole Model

In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships.

Distribution of static equilibrium points in static electric field produced by fixed electrons

Fix n electrons on the disk ｜z｜≤R. They generate a static electric field. Let a be an electron located in the disk ｜z｜≤R sin π/n. It shows that the closed disk with center a and radius R contains at least one static equilibrium point.

Electric field and force characteristic of dust aerosol particles on the surface of high-voltage transmission line

High-voltage transmission lines play a crucial role in facilitating the utilization of renewable energy in regions prone to desertification. The accumulation of atmospheric particles on the surface of these lines can significantly impact corona discharge and wind-induced conductor displacement. Accurately quantifying the force exerted by particles adhering to conductor surfaces is essential for evaluating fouling conditions and making informed decisions. Therefore, this study investigates the changes in electric field intensity along branched conductors caused by various fouling layers and their resulting influence on the adhesion of dust particles. The findings indicate that as individual particle size increases, the field strength at the top of the particle gradually decreases and eventually stabilizes at approximately 49.22 k V/cm, which corresponds to a field strength approximately 1.96 times higher than that of an unpolluted transmission line. Furthermore,when particle spacing exceeds 15 times the particle size, the field strength around the transmission line gradually decreases and approaches the level observed on non-adhering surface. The electric field remains relatively stable. In a triangular arrangement of three particles, the maximum field strength at the tip of the fouling layer is approximately 1.44 times higher than that of double particles and 1.5 times higher compared to single particles. These results suggest that particles adhering to the transmission line have a greater affinity for adsorbing charged particles. Additionally, relevant numerical calculations demonstrate that in dry environments, the primary adhesion forces between particles and transmission lines follow an order of electrostatic force and van der Waals force. Specifically, at the minimum field strength, these forces are approximately74.73 times and 19.43 times stronger than the gravitational force acting on the particles.

Single Bubble Behavior in Direct Current Electric Field

The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current （DC） electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other.

α Decays in Superstrong Static Electric Fields

Superstrong static electric fields could deform Coulomb barriers between α clusters and daughter nuclei,and bring up the possibility of speeding up α decays. We adopt a simplified model for the spherical α emitter^(212)Po and study its responses to superstrong static electric fields. We find that superstrong electric fields with field strengths|E|～0.1 MV/fm could turn the angular distribution of α emissions from isotropic to strongly anisotropic, and speed upα decays by more than one order of magnitude. We also study the influences of superstrong electric fields along the Po isotope chains, and discuss the implications of our studies on α decays in superstrong monochromatic laser fields. The study here might be helpful for future theoretical studies of α decay in realistic superstrong laser fields.

Impact of Ion Current on Total Electric Field Measurement Under HVDC Transmission Line

The total electric field(TEF) at ground level induced by high-voltage direct current(HVDC) overhead transmission lines is one of the important indexes for evaluating the lines' electromagnetic environment.Based on analyzing the existing TEF sensors and the measurement principle of ion-current density,the influence from ions on TEF measurements is quantitively studied.The results show that the ions generated by the corona from a HVDC transmission line in operation cause errors in the measurement of TEF.This error is determined through analyzing the component of total measuring current on the filed mill's sensing electrode: if no appropriate approach taken,the maximum measurement error reaches up to 4.3%.Furthermore,a method that can eliminate such error,and hence improve the accuracy of TEF sensors is designed.

Analysis on Thermal Current Field in Powertrain Cabin of Tracked Vehicles With Electric Transmission System Configuration-2

The electric transmission system congfiguration-2 is one of the main electric drives for tracked vehicles. The geometrical model for the power-train cabin is established and the preliminary design for its cooling system is implemented. The mathematic model is established for thermal current field computation, simulation and analysis in the powertrain cabin. The three-dimensional structure of the powertrain cabin is optimized. The validity of the cooling system design is proved. The foundation for optimizing the whole electric transmission system configuration is laid.

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.

Symbolic Computation and Graphic Presentation of Magneto-Static Field and Its Associated Vector Potential for a Steady Looping Current

With the advent of Computer Algebra System (CAS) such as Mathematica [1], challenging symbolic longhand calcula-tions can effectively be performed free of error and at ease. Mathematica’s integrated features allow the investigator to combine the needed symbolic, numeric and graphic modules all in one interactive environment. This assists the author to focus on interpreting the output rather than exerting the efforts of relating the scattered separate modules. In this note the author, utilizing these three features, explores the magneto-static field and its associated vector potential of a steady looping current. In particular by deploying the numeric features of Mathematica the exact value of the vector potential of the looping current conducive to its 3D graph is presented.

Hydrophobic ionic liquids/water interfacial phase transfer induced by direct current electric field

To investigate the affect of direct current electric field (DCEF) on the interfacial phase,in this paper,a hydrophobic ionic liquid (HIL)/water as liquid-liquid two-phase binary system is established by using the deioned water and l-butyl-3-methyl imidazolium hexafluorophosphate,and the topographies of the HIL nanodroplets and nanolayers in ambient water are observed by atomic force microscope (AFM).The results show the AFM exerting the DCEF can enhance the intersolubility of the HIL/water binary system and induce their interfacial phase transfer.

Influence of high voltage static electric field on ultra-weak chemiluminescence of sheep semen

Ultra_weak chemiluminescence sent forth by animals’ organs, tissures and cell organs is discussed. It is indicated that if the ultra_weak chemiluminescence of an animal is high, its metabolism is exuberant, and its pregnant rate is high. A study of the influence of ligh voltage static electric field on the luminescence of sheep sperm is carried out.

Electric-field-dependent charge delocalization from dopant atoms in silicon junctionless nanowire transistor

We study electric-field-dependent charge delocalization from dopant atoms in a silicon junctionless nanowire transistor by low-temperature electron transport measurement. The Arrhenius plot of the temperature-dependent conductance demonstrates the transport behaviors of variable-range hopping(below 30 K) and nearest-neighbor hopping(above 30 K).The activation energy for the charge delocalization gradually decreases due to the confinement potential of the conduction channel decreasing from the threshold voltage to the flatband voltage. With the increase of the source–drain bias, the activation energy increases in a temperature range from 30 K to 100 K at a fixed gate voltage, but decreases above the temperature of 100 K.

Surface Electrical Field Distribution Simulation and Insulation Characteristics Test of Polluted Insulators

In this paper,the electrical fields along the insulator surface under different scenarios,such as asymmetric pollution on top/bottom surface,and uneven circumferential distribution of surface pollution,have been calculated with finite element method for field simulation.Tests on artificial pollution insulators are conducted to study the 50% withstand voltage U50 of artificial pollution suspension insulators under different NSDD(non-soluble deposit density)and asymmetric pollution on the top/bottom surface,and study the change of leakage current with air humidity under different voltage and different ESDD(equivalent salt deposit density).The result shows that asymmetric top/bottom surface pollution has a greater impact on the insulator electrical field distribution,and the leakage current will jump under low air humidity,if had large ESDD,which has practical meanings to the anti-pollution design of the transmission line under different pollution levels across the country.

Effect of Static Magnetic Field on α-Amylase Activity and Enzymatic Reaction

The effect of magnetic field on a-amylase was studied. Under the experimental conditions, a-amylase solution was treated by 0.15 T, 0.30 T and 0.45 T static magnetic fields for a known period of time, then the activity, kinetic parameters, and the secondary conformation were investigated. The results showed that there was a considerable effect of the magnetic exposure on the α-amylase. The activity was increased by 27%, 34.1%, 37.8% compared with the control. It was also found that both kinetic parameters Km and Vm could be decreased due to the increasing magnetic field, Km decreased from 2.20×10^2 to 0.87×10^2, whereas Vm decreased from 2.0×10^3 g/min to 1.1 ×10^3 g/min. At the same time, there were some irregular changes in a-amylase secondary conformation.

Characteristics of Transient Outward Potassium Channel Exposed to 3 mT Static Magnetic Field

Acutely isolated mouse hippocampal CA3 pyramidal neurons were exposed to 3 mT static magnetic field,and the characteristics of transient outward K+ channel were studied using the whole-cell patch-clamp technique.The experiment revealed that the amplitude of transient outward potassium channel current was reduced.The maximum activated current densities of control group and exposure group were 163.62±20.68 pA/pF and 98.74±16.57 pA/pF(n=12,P<0.01) respectively.The static magnetic field exposure affected the activation and inactivation process of transient outward potassium channel current.Due to the magnetic field exposure,the half-activation voltage of the activation curves changed from 5.59±1.96 mV to 27.87±7.24 mV(n=12,P<0.05) ,and the slope factor changed from 19.43±2.11 mV to 25.87±4.22 mV(n=12,P<0.05) .The half-inactivation voltage of the inactivation curves also changed from-56.09±0.89 mV to-57.16±1.10 mV(n=12,P>0.05) and the slope factor of the inactivation curves from 8.69±0.80 mV to 10.87±1.02 mV(n=12,P<0.05) .The results show that the static magnetic field can change the characteristics of transient outward K+ channel,and affect the physiological functions of neurons.

Electric field distribution and effective nonlinear AC and DC responses of graded cylindrical composites

The perturbation method is used to study the localization of electric field distribution and the effective nonlinear response of graded composites under an external alternating-current（AC） and direct-current（DC） electric field E app = E 0（1 ＋ sin ωt）.The dielectric profile of the cylindrical inclusions is modeled by function ε i（r） = C k r k（r ≤ a）,where r is the radius of the cylindrical inclusion,and C k,k,a are parameters.In the dilute limit,the local potentials and the effective nonlinear responses at all harmonics are derived.Meanwhile,the general effective nonlinear responses are also derived and compared with the effective nonlinear responses at harmonics under the AC and DC external field.It is found that the effective nonlinear AC and DC responses at harmonics can be calculated by those of the general effective nonlinear of the graded composites under the external DC electric field.Moreover,the obtained local electrical fields show that the electrical field distribution in the cylindrical inclusions is controllable,and the maximum of the electric field inside the cylinder is at its center.

Electrical properties and electrical field in depletion layer for CZT crystals

Current—voltage (I—V) and capacitance—voltage (C—V) characteristics of Au/p-CZT contacts with different surface treatments on cadmium zinc telluride (CZT) wafer’s surface were measured with Agilent 4339B high resistance meter and Agilent 4294A precision impedance analyzer, respectively. The Schottky barrier height was 0.85±0.05, 0.96±0.05 eV for non-passivated and passivated CZT crystals by I—V measurement. By C—V measurement, the Schottky barrier height was 1.39±0.05, 1.51±0.05 eV for non-passivated and passivated CZT crystals. The results show that the passivation treatment can increase the barrier height of the Au/p-CZT contact and decrease the leakage current. The main reason is that the higher barrier height of Au/p-CZT contacts can decrease the possibility for electrons to pass through the native TeO2 film. Most of the applied voltage appears on the depleted layer and there is only a negligible voltage drops across the nearly undepleted region. Furthermore, the electric field in the depleted layer is not uniform and can be calculated by the depletion approximation. The maximum electric field of CZT crystals is Em1=133 V/cm at x=0 for non-passivated CZT crystal and Em2=55 V/cm for passivated CZT crystal, respectively.