Treatment of Dyeing Wastewater by Using Positive Pulsed Corona Discharge to Water Surface

This study investigated the treatment of textile-dyeing wastewater by using an electrical discharge technique （positive pulsed corona discharge）. The high-voltage electrode was placed above the surface Of the wastewater while the ground electrode was submerged in the wastewater. The electrical discharge starting at the tip of the high voltage electrode propagated toward the surface of the wastewater, producing various oxidative radicals and ozone. Oxygen was used as the working gas instead of air to prevent nitrogen oxides from forming. The simulated wastewater was made up with amaranth, which is a kind of azo dye. The results obtained showed that the chromaticity of the wastewater was almost completely removed within an hour. The ultraviolet/visible spectra of the wastewater treated by the electrical discharge revealed that the total hydrocarbon level also decreased significantly.     

Development of an Atmospheric Dispersion Model for Accidental Discharge of Radionuclides with the Function of Simultaneous Prediction for Multiple Domains and its Evaluation by Application to the Chernobyl Nuclear Accident

A particle random-walk model GEARN for nuclear emergency response system, Worldwide version of System for Prediction of Environmental Emergency Dose Information (WSPEEDI), was improved to predict the atmospheric dispersion of radionuclides in detail around a release point as well as on a regional scale for a transboundary nuclear accident. The main improvement is simultaneous atmospheric dispersion calculations of two nested domains, local and regional areas, achieved by exchanging particle information between the domains. In the application of the model to the Chernobyl accident, the distribution of surface deposition of ¹³⁷Cs was predicted well in the local area around Chernobyl and the European regional area. The improvements were mainly due to the consideration of the reentry of particles from the regional area to the local one and the enhancement of prediction accuracy for precipitation by the nesting calculation in the meteorological model MM5 combined with GEARN. It is concluded that the nesting model developed in this paper is appropriate for nuclear emergencies in which the prediction of both local and regional scale dispersions are required.     

The Experimental Investigations of Dielectric Barrier Discharge and Pulse Corona Discharge in Air Cleaning

The dielectric barrier discharge (DBD) and pulse corona discharge(POD) plasmagenerator was used to remove NHa, H2S, C7H8 etc. from atmosphere. The principle and charac-teristic of the two ways was discussed in the article. The test shows the result of PCD is betterthan that of DBD.     

Electrical Characteristics of Pulsed Corona Discharge Plasmas in Chitosan Solution

Pulsed discharge plasma has exhibited active potential to prepare low molecular weight chitosan. In the present study, the viscosity of ehitosan solution was decreased noticeably after treated with pulsed corona discharge plasma. An experimental investigation on electrical characteristics of pulsed corona discharge plasma in chitosan solution was conducted with a view toward getting insight into discharge process. Factors affecting I-V curve, single pulse injec- tion energy and pulse width were studied. Experimental results showed positive effect of pulsed peak voltage on discharge plasma in chitosan solution. Pulse-forming capacitor greatly influenced the discharge form, and 4 nF was observed as a suitable value for efficiently generating stable discharge plasmas. As the electrode distance was larger than 10 ram, it had slight impact on dis- charge plasma due to the excellent conductive-property of chitosan solution. The injection energy significantly increased with air flow rate, while the pulse width hardly changed as the air flow rate increased from 0.5 m^3/h to 1.0 m^3/h. This study is expected to provide reference for promoting the application of pulsed corona discharge plasma to ehitosan solution treatment.     

Branch Structure of Corona Discharge： Experimental Simulation and Chemical Properties

The branch structure of corona discharge has been investigated via C2H2 corona discharge. Carbon filament with excellent branch structure is formed in the discharge. This carbon filament offers a direct mimic of the branch structure of corona discharge. It provides a very useful way to study on the average energy, physical and chemical characteristics of corona discharge. On this basis, the chemical property of corona discharge for methane conversion is discussed.     

Experiment and Analysis on the Treatment of Gaseous Benzene Using Pulsed Corona Discharge Plasma

An experiment and analysis on removal of gaseous benzene by pulse corona inducedplasma is presented in this article. Important parameters effecting removal efficiency have been investigated, such as pulse peak voltage, pulse frequency, gas inlet concentration, gas flow rate and reactor temperature. The result shows that the removal efficiency increases with the increase in pulse peak voltage, pulse frequency and reactor temperature, but decreases in the rise of gas inlet concentration and gas flow rate. On the condition of Vp = 36 kV, f = 80 Hz, C = 1440 mg/m^3 and Q = 640 ml/min, the largest removal efficiency is 98%. Finally, the reacted products are qualitatively analysed and the reaction processes are deduced in combination with plasma-chemistry theory.     

Study on Detection of Negative Corona Discharge Generated in Rod-Plane Air Gap by Using External Electrode Method

A detective method of a negative corona discharge by means of an external electrode is presented. The relationship between an area of the external electrode and a detected voltage waveform is examined experimentally. This experimental study is carried out with the use of a rod-plane air gap. The results obtained will be applicable to problems associated with silos, ducts, and high-voltage equipment.     

Analysis of Energetic Species Caused by Contact Glow Discharge Electrolysis in Aqueous Solution

Contact glow discharge electrolysis is a non-Faradaic electrochemical process with an abnormal relationship between the current and voltage. Hydroxyl radicals, hydrogen radicals and hydrogen peroxide can be produced under the glow discharge, which are often used to degrade organic contaminants in aqueous solution. In this study, with 4-nitrophenol taken as an example of contaminants and tert-butanol as a scavenger of hydroxyl radicals, the role of energetic species in degrading organic compounds was examined in detail. Moreover, the effects of the applied voltage, solution conductivity and pH on the formation of three energetic species were also observed. The formation rate constants of the three energetic species were calculated based on the experimental data.     

Removal of Volatile Organic Compounds (VOCs) Mixture by Multi-Pin-Mesh Corona Discharge Combined with Pulsed High-Voltage

Removal of single component and binary mixtures of benzene and m-xylene using a multi-pin-mesh reactor was studied to find the decomposition characteristics, carbon balance and CO2 selectivity. The decomposition rate of benzene in mixture was approximately 16% lower than that of single component benzene. However, the decomposition rate of m-xylene in mixture was slightly higher than that of single component m-xylene. Carbon balance of the mixture decomposition process achieved a lower level than that of single component benzene/m-xylene. Increase in the specific input energy was helpful to improve CO2 selectivity in the single component decomposition process, while the specific input energy had a negligible effect on CO2 selectivity in the mixture decomposition process. By changing the oxygen content in background gas, we found that different types of radicals showed different reaction activities toward benzene and m-xylene. Benzene was more likely to react with nitrogen-containing radicals, while m-xylene was more likely to react with oxygen-containing radicals.     

Prediction of DC Corona Onset Voltage for Rod-Plane Air Gaps by a Support Vector Machine

This paper proposes a new method to predict the corona onset voltage for a rodplane air gap, based on the support vector machine(SVM). Because the SVM is not limited by the size, dimension and nonlinearity of the samples, this method can realize accurate prediction with few training data. Only electric field features are chosen as the input; no geometric parameter is included. Therefore, the experiment data of one kind of electrode can be used to predict the corona onset voltages of other electrodes with different sizes. With the experimental data obtained by ozone detection technology, and experimental data provided by the reference, the efficiency of the proposed method is validated. Accurate predicted results with an average relative less than3% are obtained with only 6 experimental data.     

Neural Network Prediction of Disruptions Caused by Locked Modes on J-TEXT Tokamak

Prediction of disruptions caused by locked modes using the Back-Propagation （BP） neural network is completed on J-TEXT tokamak. The network, which is based on the BP neural network, uses Mirnov coils and locked mode coils signals as input data, and outputs a signal including information of prediction of locked mode. The rate of successful prediction of locked modes is more than 90%. For intrinsic locked mode disruptions, the network can give a prewarning signal about 1 ms ahead of the locking-time. For the disruption caused by resonant magnetic perturbation （RMPs） locked modes, the network can give a prewarning signal about 10 ms ahead of the locking-time.     

Evaluation of Excitation Function for ^45Sc

Present work contains the evaluated neutron induced excitation function data for ^45Sc, and mainly on （n, 2n） and （n, γ） reaction channels. The related experimental data were collected, analyzed and corrected for ^45Sc（n, γ）, （n, 2n） and other reaction channels. The evaluated excitation functions were based on nuclear reaction model code system EMPIREII, the experimental data and the original evaluation data.     

Numerical Modelling Point-to-Plane of Negative Corona Discharge in N_2 Under Non-Uniform Electric Field

The paper presents a simulation model of the negative corona discharge in N_2 under various pressures.The simulated discharge is of a negative point-to-plane mass type,with an inter-electrode separation distance of 20 mm and a symmetry about the axis of discharge.This simulation investigates the behavior of the neutral density and temperature for different pressures in the range of 0.1-10.0 bar.The spatial and temporal evolution of the neutral gas is analyzed based upon the equations of continuity,momentum and energy in a two-dimensional cylindrical geometry model.For that geometry of the system,the FCT(Flux Corrected Transport) technique was adopted.The results show that the pressure plays a significant role of the neutrals dynamics.     

Evaluation of Excitation Function for ^181Ta

Present work contains the evaluated neutron induced excitation function data for ^181Ta, and mainly on （n, γ） reaction channel. The related experimental data were collected, analyzed and corrected for ^181Ta （n, γ） reactions, and other reaction channels. The evaluated excitation functions were based on nuclear reaction model code system EMPIRE- II, the experimental data and the original evaluation data.     

Removal of NO and SO2 in Corona Discharge Plasma Reactor with Water Film

In this paper, a novel type of a corona discharge plasma reactor was designed, which consists of needle-plate-combined electrodes, in which a series of needle electrodes are placed in a glass container filled with flue gas, and a plate electrode is immersed in the water. Based on this model, the removal of NO and SO2 was tested experimentally. In addition, the effect of streamer polarity on the reduction of SO2 and NO was investigated in detail. The experimental results show that the corona wind formed between the high-voltage needle electrode and the water by corona discharge enhances the cleaning efficiency of the flue gas because of the presence of water, and the cleaning efficiency will increase with the increase of applied dc voltage within a definite range. The removal efficiency of SO2 up to 98%, and about 85% of NO~ removal under suitable conditions is obtained in our experiments.     

Evaluation and Optimization of Electrode Configuration of Multi-Channel Corona Discharge Plasma for Dye-Containing Wastewater Treatment

A discharge plasma reactor with a point-to-plane structure was widely studied experimentally in wastewater treatment.In order to improve the utilization efficiency of active species and the energy efficiency of this kind of discharge plasma reactor during wastewater treatment,the electrode configuration of the point-to-plane corona discharge reactor was studied by evaluating the effects of discharge spacing and adjacent point distance on discharge power and discharge energy density,and then dye-containing wastewater decoloration experiments were conducted on the basis of the optimum electrode configuration.The experimental results of the discharge characteristics showed that high discharge power and discharge energy density were achieved when the ratio of discharge spacing to adjacent point distance(d/s) was 0.5.Reactive Brilliant Blue(RBB) wastewater treatment experiments presented that the highest RBB decoloration efficiency was observed at d/s of 0.5,which was consistent with the result obtained in the discharge characteristics experiments.In addition,the biodegradability of RBB wastewater was enhanced greatly after discharge plasma treatment under the optimum electrode configuration.RBB degradation processes were analyzed by GC-MS and IC,and the possible mechanism for RBB decoloration was also discussed.     

Factors Influencing the Electron Yield of Needle-Ring Pulsed Corona Discharge Electron Source for Negative Ion Mobility Spectrometer

A simple negative ion mobility spectrometer （IMS） is designed and used to investi- gate the factors that influence the number and efficiency of electrons generated by the needle-ring pulsed corona discharge electron source. Simulation with Ansoft Maxwell 12 is carried out to analyze the electric field distribution within the IMS, and to offer the basis and foundation for analyzing the measurement results. The measurement results of the quantities of electrons show that when the drift electric field strength and the ring inner diameter rise, both the number of ef- fective electrons and the effective electron rate are increased. When the discharge voltage becomes stronger, the number of effective electrons goes up while the effective electron rate goes down. In light of the simulation results, mechanisms underlying the effects of drift electric field strength, ring inner diameter, and discharge voltage on the effective electron number and effective electron rate are discussed. These will make great sense for designing negative ion mode IMS using the needle-ring pulsed corona discharge as the electron source.     

偏心率对核主泵叶轮口环密封激励力的影响研究

为探究转子偏心率对核主泵转子密封激励力的影响,基于雷诺时均N-S方程和RNG k-ε湍流模型,选取平面密封、迷宫密封和螺旋密封3种口环结构方案,对核主泵口环间隙内部流动进行数值计算,得到口环间隙区域压力、泄漏量及其密封激励力的分布规律。结果表明,模型泵性能预测值和试验值较为吻合,扬程最大误差为4.78%。在转子无偏心时,相对于平面密封,采用螺旋密封方案时口环泄漏量显著降低93.1%,而密封激励力增加63%。偏心率为10%时,口环压力分布沿周向较为均匀;当偏心率为30%时,周向靠近偏心位置处,口环间隙内部产生带状压力突升区,相对于无偏心方案,平面密封的泄漏量显著降低43.6%,而密封激励力增大4.4倍,迷宫密封和螺旋密封方案可显著降低转子偏心产生的密封激励力,其中迷宫密封可显著降低55%;偏心率为50%时,口环间隙内部带状压力突升区域偏向高压侧。本数值预测方法为揭示偏心转子对核主泵口环密封激励力的影响提供理论依据。      

Transition from Spark Discharge to Constricted Glow Discharge in Atmospheric Air by Capacitor Coupled Discharge

The transition from a spark discharge to a constricted glow discharge in atmospheric air was studied with a capacitor coupled pin-to-water plasma reactor. The reason of the transition is considered to be of various factors, namely the change of the air gap due to the polarization of water molecules by the electric field, the feedback effect of the capacitors, and the ion trapping mechanism. The effects of the frequency of the power supply, inter-electrode gap, and coupled capacitance on the discharge transition were also investigated.     

从实验熔合激发函数抽取势垒高度

库仑势垒在低能重离子核反应中扮演了重要的角色,但它不能被直接测量,需通过不同类型的重离子核反应间接提取。目前对库仑势垒的系统研究大都比较依赖于所采用的相互作用势模型和反应理论模型。本工作采用实验熔合截面与能量的乘积相对于能量的一阶微分作为穿透系数,并将穿透系数最大值一半的位置定义为熔合反应的经验势垒高度。该定义不依赖于理论模型,具有优秀的稳定性和可靠性。依据该定义,采用耦合道模型CCFULL及Wong公式拟合12组具有代表性的实验熔合激发函数,进而提取库仑势垒高度。通过比较本工作中从实验值抽取的势垒高度和不同理论势模型预测的势垒高度,以及其随同位旋不对称度的变化,发现Bass80和WKJ公式与本工作的结果最吻合。