Increase Of Electric Field Intensity Research Articles

Spectrum and dissociation properties of fluoro trichloro methane molecule in radiational field

The ozone layer in the stratosphere of the earth’s atmosphere, which can be destroyed by CFC-11 molecule, plays a crucial role in human survival because it can absorb most of the harmful radiation from the sun and effectively protect the earth’s biology. Therefore, it is of evident significance to investigate the properties of CFC-11 molecule. By Motivated by this and the adoption of B3LYP complex function at a level of 6-311++g(3df, 3pd) basis set, we carry out a series of theoretical studies of the Freon material CFC-11 (CFCl3) molecules, including the studies of the equilibrium structure, electric dipole moment, total energy, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) level, energy gap, infrared and Raman spectrum, C—F dissociation characteristics of CFC-11 molecule, and the effect of the applied electric field on CFC-11 molecule as well. The results show that the maximum error between the theoretical calculation value and the experimental value is less than 2% for an optimized ground state structure; the C—F bond length and C—Cl bond length extend with the increase of electric field intensity, but the degree of change of C—F bond length is much stronger than that of C—Cl; the HOMO energy level and total energy go up and then come down as the external field rises, while the LUMO energy level goes up as the field increases. The energy gap <i>E</i><sub>g</sub> first increases and then decreases with the variation of <i>E</i><sub>H</sub> and <i>E</i><sub>L</sub>. The dipole moment without electric field is a minimum value, and the external electric field leads the molecular polarity to increase and the molecular activity to strengthen. The electric field influences the absorption intensity of infrared and Raman spectrum. The infrared and Raman spectrum move toward the long wave under the action of positive electric field, while they move toward the short wave under the action of negative electric field. The red- or blue-shift of infrared and Raman spectrum occur with the change of electric field. The electric field can be adopted as an auxiliary means to separate the overlapping or quasi-overlapping spectral lines. The potential well depth decreases with the increase of the reverse electric field until it vanishes, which causes the bound state ability of C—F bond of CFC-11 molecule to gradually degrade. This paper is expected to provide a feasible and effective tunable means for the final dissociation and degradation of CFC-11 molecules.

Vibration of two-dimensional hexagonal boron nitride

ABSTRACT The dynamic behavior of two-dimensional nanostructures is important to the future application of nano devices. The vibrational behaviors of single-layered hexagonal boron nitride (h-BN) are studied by molecular dynamics simulation and continuum plate model. The bending stiffness and Poisson's ratios of h-BN along zigzag direction and armchair direction are calculated. H-BN is softer compared with graphene. The continuum plate model can predict the vibration of h-BN with four edge-clamped boundary conditions well. The electric fields in different directions have obvious influence on the vibration of h-BN. The natural frequency of h-BN changes linearly with the electric field intensity along the polarization direction. The natural frequency of h-BN decreases with the increase of electric field intensity along both positive and negative non-polarization direction. While the natural frequency of h-BN increases with the increase of electric field intensity along both positive and negative transverse electric field.

Natural convection heat transfer of nanofluid in a cavity under an inhomogeneous electric field

Natural convective heat transfer of nanofluid consisted of transformer oil and Al2O3 nanoparticles in a cavity under a non-uniform high electric field intensity was experimental investigated. The main objective is looking for a coupling enhanced method by nanofluid and electric field. It is found that when the effect of gravity is ignored, the electric field forces applied on the working fluids induce an electric convection and thence induce significant heat transfer enhancement. This enhancement effect increases rapidly with the increase of electric field intensity, the nanoparticles mass concentration of nanofluid and the heat flux. When the effect of gravity exists, a coupled convection is caused by both gravity and electric field force together. For pure transformer oil, the influences of electric field force and gravity on the heat transfer almost offset each other. However, for nanofluid, the impact of the electric filed force is dominant. The study results revealed the enhanced mechanism of natural convection heat transfer of nanofluid under electric field and provided some useful technical support for practical application.

Effects of electrolyte thickness, chloride ion concentration, and an external direct current electric field on corrosion behaviour of silver under a thin electrolyte layer

ABSTRACTEffects of electrolyte thickness, chloride ion concentration, and an external direct current electric field (DCEF) on the corrosion behaviour of silver under a thin electrolyte layer (TEL) were investigated using electrochemical and surface techniques. The results indicate the corrosion rate of silver increases with the decrease of TEL thickness and the increase of chloride ion concentration. Moreover, an interesting conclusion was drawn that the corrosion rate of silver near the positive plate of DCEF first increases and then decreases with the increase of electric field intensity. In a DCEF, different polarisation behaviours of silver at different positions were attributed to the differences of the local corrosion environment.

Influence of electric field on the viscosity of waxy crude oil and micro property of paraffin: A molecular dynamics simulation study

Electrical treatment is a useful method for reducing viscosity of waxy crude oil. Molecular dynamics simulation was employed to study the influence of electric field on viscosity of waxy crude oil and micro properties of paraffin. The waxy crude oil model consists of light oil and 24.9% by weight of paraffin. The simulation results show that viscosity decreases when electric field is applied. The larger the electric field intensity, the greater the decreasing extent of viscosity. The electrical viscosity-reducing effect is better at lower temperatures. The radial distribution function and diffusion coefficient were analyzed for explaining the reason of viscosity decreasing. The radial distribution function results confirm that electric field promotes aggregation of paraffin molecules. Diffusion coefficient increases with the increase of electric field intensity. At the same temperature, the higher the electric field strength, the larger the increasing extent of diffusion coefficient. In a certain electric field intensity, the lower the temperature, the greater the increasing extent. The changing tendency of diffusion coefficient is consistent with the trend of viscosity reduction under electrical treatment. It is suggested that the change of diffusion coefficient is the main reason for electrical viscosity-reducing effects, the contribution of aggregation is smaller than increasing of diffusion coefficient.

Enhanced extraction of phenolic compounds from onion by pulsed electric field (PEF)

The extraction of water-soluble phenolic compounds from onion assisted by pulsed electric field treatment (PEF) was investigated as well as the antioxidant activity of the extracts. Results indicated that the yield of water-soluble phenolic compounds (PC) and flavonoid compounds (FC) from onion was significantly increased after treated by PEF treatment following water extraction. Meanwhile, the antioxidant activity of extracts increased with the increase in electric field intensity and treatment time. Box–Behnken design was employed to optimize the extraction process. The optimal conditions were 2.5 kV/cm, 90 pulses and 45°C for both of PC and FC. Under those conditions, the content of PC and FC in extracts was 102.86 mg GAE 100 g–1 FW and 37.58 mg QE 100 g–1 FW, increased by 2.2 and 2.7 times, respectively, in comparison to control (Non-PEF treatment) (PC is 32.13 GAE 100 g–1 FW，FC is 10.22 mg QE 100 g–1 FW). Although the extraction yields of PC and FC for PEF-assisted aqueous extraction was just 1/3 and 1/2 of soxhlet extraction, compared to conventional extraction methods with toxic, organic solvent, PEF-assisted aqueous extraction method is a selective, environmental friend process to recover water-soluble PC and FC from onion. Practical application Onion is abundant of phenolic compounds, particularly flavonols which are considered to be a reduced risk of many diseases by inhibition of lipid peroxidation. PEF processing as a non-thermal technology for preservation of liquid foods has been investigated extensively during the last decades without destroying original sensorial and nutritional properties of food. In this study, it demonstrated that as efficient cell wall disruption technique, the aqueous extraction of phenolic compounds (PC) and flavonoid compounds (FC) from onion was facilitated significantly by PEF treatment. Therefore, PEF-assisted aqueous extraction method has great potential as a selective, environmental friend process to recover water-soluble PC and FC from onion.

Adsorption of lithium polysulfides on an anatase (1 0 1) and an [formula omitted]-Al2O3 (0 0 0 1) surface under external electric field with first principles calculations

The “shuttle effect” induced by the dissolution and diffusion of the Li2Sx (4⩽x⩽8) into the electrolyte is a crucial problem of a LiS battery. Anatase or Al2O3 can be used as an additive to suppress the “shuttle effect”. First-principles approach coupled with van der Waals (vdW) interaction is used to calculate the adsorption energies of Li2Sx (x=4,6,8) molecules on an anatase (1 0 1) or an α-Al2O3 (0 0 0 1) surface. The results show that the adsorption of the molecules on an α-Al2O3 (0 0 0 1) is stronger than that on an anatase (1 0 1) surface. Furthermore, owing to the existence of an electric field inside the battery during the charge-discharge process, the external electric field effects on the adsorption are investigated. As a result, the adsorption energy (absolute value) almost linearly increases with the increase of electric field intensity in the range from -0.16 to 0.16 V/Å. In addition, the responses of different Li2Sx molecules on an anatase (1 0 1) surface or an α-Al2O3 (0 0 0 1) surface to the external electric fields are different.

Joint effect of electric and magnetic field on electron energy spectrum in spherical nanostructure ZnS/CdSe/ZnS

The electron energy spectrum in inverted core-shell quantum dot driven by magnetic and electric fields is studied. The parallel and perpendicular electric and magnetic fields are considered. The Schödinger equation is solved using the method of expansion of the electron wave function on the basis of wave functions in the nanostructure without the external fields.The formation of the electron ground state under the influence of the electric and magnetic field is researched. It is shown that this state is successively formed by the states with m ≤ 0 (Aharonov-Bohm effect) when the magnetic field induction increases. This effect vanishes when the electric field intensity increases and if the magnetic field is parallel to the electric one. The electron ground state is characterized only by quantum number m = 0 in the whole range of magnetic field induction when the electric field intensity is bigger than certain critical magnitude. When the electric field intensity increases, being perpendicular to the magnetic one, the cylindrical symmetry of problem is broken and the wave function of electron ground state is obtained as a series, containing the states with different values of magnetic quantum number. Their partial contributions essentially depend on the magnitudes of electric field intensity and magnetic field induction. The effect of magnetic field on electron ground state energy decreases when the external fields are perpendicular.The peculiarities of the formation of electron energy spectrum due to the electric and magnetic field should be displayed on the selection rules and the energies of quantum transitions and, thus, on the optical properties of nanostructure.

Electrically tuned whispering gallery modes microresonator based on microstructured optical fibers infiltrated with dual-frequency liquid crystals

Abstract An electrically tunable whispering gallery mode (WGM) microresonator based on an HF-etched microstructured optical fiber (MOF) infiltrated with dual-frequency liquid crystals (DFLCs) is proposed and experimentally demonstrated for the investigation of the crossover frequency and Freedericksz transition of DFLCs. Experimental results indicate that for applied electric field with operation frequency below the crossover frequency, WGM resonance wavelength decreases with the increment of applied electric field strength. On the contrary, for applied electric field with operation frequency beyond the crossover frequency, WGM resonance dips show red shift as the applied electric field intensity increases. The proposed electrically tunable microcavity integrated with DFLCs is anticipated to find potential applications in optical filtering, all-optical switching, and electrically manipulated bi-directional micro-optics devices.

Simulation study of the performance of new micropattern gaseous detectors

The micropattern gaseous detectors (MPGDs) are widely used in high-energy physics experiment, such as detector upgrade projects in LHC, due to its excellent performance on rate capability, spatial and time resolutions. In this paper, we studied the performances of GEM, FTM and $$\mu $$ -RWELL detectors on time and spatial resolutions using Monte Carlo simulation methods and compared their performances and characteristics at various working conditions. Result shows that time resolution of MPGDs improves with the increase of electric field intensity in drift region, while spatial resolution shows the reverse tendency. In addition, detectors operating with an electronegative gas mixture show better performances on both time and spatial resolution. We studied the performance of triple-GEM, FTM and $$\mu $$ -RWELL detectors with Monte Carlo simulation. In this paper, ANSYS and GARFIELD are used to build full electric field model of the detector. The time resolution and spatial resolution are derived, which are very important for triggering performance and track reconstruction ability. These results will provide references on detector design and the technology chosen in LHC detector upgrade projects.

Electrothermal Convection in Dielectric Maxwellian Nanofluid Layer

The influence of rheological behavior on the natural convection in a dielectric nanofluid with vertical AC electric field is investigated. The rheology of the nanofluid is described by Maxwell model for calculating the shear stresses from the velocity gradients. The employed model introduces the combined effects of movement of the molecules of the fluid striking the nanoparticles, thermophoresis and electrophoresis due to embedded nanoparticles. The exact solutions of the eigen model value problem for stress-free bounding surfaces are obtained analytically using one term Galerkin method to find the thermal Rayleigh number for onset of both non-oscillatory (stationary) and oscillatory motions. It is found that the oscillatory modes are possible for both bottom and top-heavy distributions of nanoparticles. It is observed that the value of critical Rayleigh number is decreased by a substantial amount with the increase in electric field intensity, whereas role of viscoelasticity (time relaxation parameter) is to hasten the occurence of oscillatory modes appreciably. The thermal Prandtl number is found to delay the occurence of oscillatory modes. These results are also shown graphically.

Molecular structure and properties of salt cross-linked polyethylene under external electric field based on density functional theory

Cross-linked polyethylene is the main power cable insulation material and is widely used in high voltage cables. In order to study the effect of external electric field on the molecular structure of salt cross-linked polyethylene, in this paper we use the basis set of def2-TZVP for Zn atom, uses the basis set of 6-31(d) for C, H, O atoms, and uses the Minnesota density functional (M06-2X) to optimize the molecular structure of salt cross-linked polyethylene, then we obtain the stable structure of its ground state. On this basis, the molecular structure, total energy, kinetic energy, potential energy, dipole moment and polarizability changes of salt cross-linked polyethylene under the action of different external electric fields (from 0 to 0.020 a.u.) are studied by the same method. The influence of external electric field on energy level, energy gap, orbital distribution and composition of frontier orbit are studied. And the effect of external electric field on bond level, breaking bond and infrared spectrum of atoms are also discussed. The research results show that as the external electric field intensity increases, the cross-linked polyethylene molecule is gradually transformed from the spatial network structure into a linear structure, and the total energy and kinetic energy of the molecule are reduced, but its potential energy, dipole moment and polarizability are gradually increased. The highest occupied molecular orbital energy level increases with the increase of external electric field intensity. The lowest unoccupied molecular orbital energy level starts to decrease continuously from the electric field intensity of 0.011 a.u. (1 a.u. = 5:1421011 V/m), the energy gap decreases continuously, and the critical breakdown field intensity is 11.16 GV/m. With the external electric field increasing dramatically, the highest occupied molecular orbital is obviously converged at chain end in the direction of inverse electric field. Its orbital composition is more than 60%, contributed by the C atom of methyl group in the polyethylene terminal. The molecular polyethylene chain end of the inverse electric field direction exhibits an electrophilic reactivity, and C atoms are more likely to lose electrons. The Mayer bond order value of the CC bond decreases gradually, which leads the CC bonds to break more easily, and thus forming the methyl carbon negative ions. The lowest unoccupied molecular orbital moves along the electric field direction and is converged at the other end of polyethylene chain, nearly 80% of its orbital composition is contributed by the methyl of polyethylene chain end. The molecule shows a nucleophilic reactivity at the polyethylene end along the electric field direction, methyl is easier to obtain the electrons. The Mayer bond order value of the CH bond decreases gradually, and it brings about the CH bond more likely to break into H positive ions. The infrared absorption peaks of polyethylene chains are mainly concentrated in the high frequency region. With the increase of electric field intensity, the red shift occurs and the bond energy of polyethylene chain decreases. The infrared absorption peak of the cross-linked salt bridge is mainly concentrated in the low frequency area. Although there are both red shift and blue shift, the effect of red shift is more obvious, and the energy of the whole salt bridge decreases. From the variation of molecular potential energy, energy gap and Mayer bond order value, it is found that the stability of salt cross-linked polyethylene molecular system decreases with the increase of external electric field intensity.

Ultra-high voltage electron microscopy investigation of irradiation induced displacement defects on AlGaN/GaN HEMTs

Irradiation effects produced by high energy heavy ions and electrons on AlGaN/GaN high electron mobility transistor (HEMT) were investigated using ultra-high voltage electron microscopy (HVEM), optical measurements, and device characteristics analysis. The dislocation loop created on a thick (1.5μm) sample irradiated by 18MeV Ni ions was observed by HVEM. The distribution of the defects matched the calculated distribution obtained using the stopping and range of ions in matter (SRIM) code. In-situ dislocation loop generation was observed in the sample during a high energy (2MeV) electron irradiation by using HVEM. Device characteristics were found to remain stable, no increase in leakage current or electric field intensity being noticed up to a high radiant fluence of Ni and electron irradiation. These results demonstrate a high radiation tolerance of the device for space applications.

Triboluminescence modulated by humidity

Triboluminescence (TL) reflects the characteristics of real-time optical signals generated in the process of friction, hence is promising in real-time monitoring and surface study. By studying the sliding between SiO2 and Al2O3, we found that triboluminescence can be modulated quantitatively by modifying ambient humidity. The trend of TL intensity varies at different ranges of humidity and there exists a critical humidity. TL intensity rises initially and reaches its peak at critical humidity before it diminishes and eventually decreases to zero. It results from the decrease of energy barrier of tribo-charging and the increase of electric field intensity below critical humidity, and for humidity above critical humidity, the rapid growth of surface conductivity and a shorter distance account for smaller possibility of gas collision.

Effects of electric field on micro-scale flame properties of biobutanol fuel.

With the increasing need of smaller power sources for satellites, energy systems and engine equipment, microcombustion pose a potential as alternative power source to conventional batteries. As the substitute fuel source for gasoline, biobutanol shows more promising characteristics than ethanol. In this study, the diffusion microflame of liquid biobutanol under electric field have been examined through in-lab experiment and numerical simulation. It is found that traditional gas jet diffusion flame theory shows significant inconsistency with the experimental results of micro scale flame in electric field. The results suggest that with the increase of electric field intensity, the quenching flow rate decrease first and increase after it reach its minimum, while the flame height and highest flame temperature increase first and drop after its peak value. In addition, it was also observed that the flame height and highest temperature for smaller tube can reach its maximum faster. Therefore, the interaction between microscale effect and electric field plays a significant role on understanding the microcombustion of liquid fuel. Therefore, FLUENT simulation was adopted to understand and measure the impacts of microflame characteristic parameters. The final numerical results are consistent with the experimental data and show a high reliability.

The tool electrode investigation of electrostatic field-induced electrolyte jet (E-jet) electrical discharge machining

This investigation addresses concerns in micro-electrical discharge machining (EDM) such as high tool electrode preparation cost, tool electrode wear, and tool electrode compensation by proposing a new electrostatic field-induced electrolyte jet tool electrode. This method utilizes the theory that in a strong direct current electric field, the electrolyte at the capillary tube outlet can form a Taylor cone based on the balance of electric field force and surface tension. Coupled with the increase of electric field intensity, a very fine jet can eject from the tip of the Taylor cone, and this induced charge on the tip leads to a discharge to the workpiece which can remove debris from the workpiece surface. After the discharge, the induced charge at the tip is neutralized, leading to the surface tension outweighing the electric field force and the withdrawal of the fine jet. As a result, the cyclic pulse discharge process is generated. During the process, the tip of the fine jet serves as the tool electrode. This paper identifies this cyclic pulse electrolyte jet tool electrode generation and discharge process in action and tests the machining ability of this tool electrode on a silicon wafer. This electrolyte jet tool is also shown to have no wear or compensation issues, and the cost compared to conventional EDM is shown to be small.

Structural properties and digestibility of pulsed electric field treated waxy rice starch

Waxy rice starch was subjected to pulsed electric field (PEF) treatment at intensity of 30, 40 and 50kVcm−1. The impact of PEF treatment on the granular morphology, molecular weight, semi-crystalline structure, thermal properties, and digestibility were investigated. The micrographs suggested that electric energy could act on the granule structure of starch granule, especially at high intensity of 50kVcm−1. Gelatinization onset temperature, peak temperature, conclusion temperature and enthalpy value of PEF treated starches were lower than that of native starch. The 9nm lamellar peak of PEF treated starches decreased as revealed by small angle X-ray scattering. The relative crystallinity of treated starches decreased as the increase of electric field intensity. Increased rapidly digestible starch level and decreased slowly digestible starch level was found on PEF treated starches. These results would imply that PEF treatment induced structural changes in waxy rice starch significantly affected its digestibility.

에틸렌 처리를 위한 충진층 유전체배리어방전 플라즈마 반응기의 특성

This work investigated the characteristics of a packed-bed plasma reactor system and the performances of the plasma reactors connected in series or in parallel for the decomposition of ethylene. Before the discharge ignition, the effective capacitance of the γ-alumina packed-bed plasma reactor was larger than that of the reactor without any packing, but after the ignition the effective capacitance was similar to each other, regardless of the packing. The energy of electrons created by plasma depends mainly on the electric field intensity, and was not significantly affected by the gas composition in the range of 0~20% (v/v) oxygen (nitrogen : 80~100% (v/v)). Among the various reactive species generated by plasma, ground-state atomic oxygen and ozone are understood to be primarily involved in oxidation reactions, and as the electric field intensity increases, the amount of ground-state atomic oxygen relatively decreases while that of nitrogen atom increases. Even though there are many parameters affecting the performance of the plasma reactor such as a voltage, discharge power, gas flow rate and residence time, all parameters can be integrated into a single parameter, namely, specific input energy (SIE). It was experimentally confirmed that the performances of the plasma reactors connected in series or in parallel could be treated as a function of SIE alone, which simplifies the scale-up design procedure. Besides, the ethylene decomposition results can be predicted by the calculation using the rate constant expressed as a function of SIE.

Effect of the direct current electric field on the initial corrosion of steel in simulated industrial atmospheric environment

The effects of the direct current (DC) electric field on the initial corrosion of steel in simulated solution were investigated using measurements of weight loss and polarization curves, XRD and SEM techniques. The major constituents of the corrosion products are α- and γ-FeOOH in SO42− solution. It was found that the corrosion rate of steel increased with the increase of DC electric field intensity. And the DC electric field suppresses the growth of α-FeOOH and the transformation of γ-FeOOH to α-FeOOH. All these lead to the reduction of the protective ability of rust layer and accelerate further corrosion of steel.

Electrospinning of polyacrylonitrile nanofibers using strain-hardening spinning solutions

The electrospinning of polyacrylonitrile (PAN) fibers from strain-hardening PAN solutions was studied. The strain-hardening PAN electrospinning solutions were prepared by adding ultrahigh-molecular-weight PAN (UHMWPAN) into medium-molecular-weight PAN (MMWPAN) solutions. The strain-hardening behavior of the solutions was evidenced by the CaBER extensional rheological tests. In electrospinning of PAN nanofibers, the solutions containing UHMWPAN were found to be stable when large electric field intensity was applied at a constant source-target distance, different from the case that a solution without UHMWPAN was used. PAN nanofibers with smaller diameter (270 nm compared with 496 nm for the nanofibers containing no UHMWPAN) could be electrospun from the strain-hardening solutions at larger electric field intensity and no beaded fibers were observed. The results of X-ray diffraction (XRD) and mechanical tests showed that the crystallinity, crystal orientation and mechanical performance of electrospun PAN nanofibers were improved with the increase of electric field intensity.