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隧道砂层段排水性能对水压与排水量的影响 预览
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作者 刁钰 贾镇阳 +3 位作者 李光帅 褚振西 高泽东 郭勇志 《水利水电技术》 北大核心 2019年第4期23-31,共9页
为保证运营期某隧道衬砌结构安全提供理论依据,需提出排水量与衬砌水压荷载之间的关系。通过ABAQUS数值模拟软件,将模型中隧道排水系统和初支统一视为一层排水介质,简化为一维第三类边界条件,并利用温度场与渗流场的对应关系,使用温度... 为保证运营期某隧道衬砌结构安全提供理论依据,需提出排水量与衬砌水压荷载之间的关系。通过ABAQUS数值模拟软件,将模型中隧道排水系统和初支统一视为一层排水介质,简化为一维第三类边界条件,并利用温度场与渗流场的对应关系,使用温度场模拟渗流场,在保证精度的同时,极大的提高了计算效率。对数值模拟出的变量关系进行曲线拟合,以得到简化计算公式。研究表明,对于本工程,流量与水压1个月内迅速下降并稳定。初支渗透性减小,隧道压力水头增加。当表面渗透系数K≤3×10^-5 d^-1时,可认为初支不透水,承担全部水压;当K≥3 d^-1时,可认为初支完全透水,不承担水压力,不影响隧道排水;当表面渗透系数3×10^-5≤K≤3 d^-1时,稳定水头高于设计水头,承担部分水压力。拟合公式可以合理反应表面渗透系数、水头、排水量、时间的相互关系。 展开更多
关键词 隧道 砂层 排水量 水头 数值模拟 渗流场 堵水限排
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Electric characteristic and cavitation bubble dynamics using underwater pulsed discharge
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作者 单鸣雷 陈秉岩 +3 位作者 姚澄 韩庆邦 朱昌平 杨雨 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第7期16-22,共7页
Underwater pulsed discharge is widely applied in medicine, machining, and material modification.The induced cavitation bubble and subsequent cavitation collapse are considered the major motivations behind these applic... Underwater pulsed discharge is widely applied in medicine, machining, and material modification.The induced cavitation bubble and subsequent cavitation collapse are considered the major motivations behind these applications. This paper presents an underwater pulsed discharge system.The experimental setup is established to induce and investigate the cavitation bubble assisted with a high-speed camera. Three aspects, including the characteristic of the discharge with different applied voltages and conductivities, the evolution of the cavitation bubble profile, and the energy efficiency of cavitation bubble inducing, are investigated, respectively. Especially, the mechanism of pre-discharge time delay in the low field intensity case is explained using the Joule heat effect.The results show the validity of the underwater pulsed discharger and experimental setup. The present underwater pulsed discharger is proved to be a simple, portable, and easy-to-implement device for the investigation of cavitation bubble dynamics. 展开更多
关键词 UNDERWATER pulsed DISCHARGE CAVITATION BUBBLE ELECTRIC DISCHARGE CHARACTERISTIC high-speed camera
Influence of nitrogen impurities on the characteristics of a patterned helium dielectric barrier discharge at atmospheric pressure
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作者 张雨晖 宁文军 +1 位作者 戴栋 王乔 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第7期23-37,共15页
In this paper, a two-dimensional axisymmetric fluid model was established to investigate the influence of nitrogen impurity content on the discharge pattern and the relevant discharge characteristics in an atmosphere ... In this paper, a two-dimensional axisymmetric fluid model was established to investigate the influence of nitrogen impurity content on the discharge pattern and the relevant discharge characteristics in an atmosphere pressure helium dielectric barrier discharge(DBD). The results indicated that when the nitrogen content was increased from 1 to 100 ppm, the discharge pattern evolved from a concentric-ring pattern into a uniform pattern, and then returned to the concentricring pattern. In this process, the discharge mode at the current peak moment transformed from glow mode into Townsend mode, and then returned to glow mode. Further analyses revealed that with the increase of impurity level, the rate of Penning ionization at the pre-ionization stage increased at first and decreased afterwards, resulting in a similar evolution pattern of seed electron level. This evolution trend was believed to be resulted from the competition between the N2 partial pressure and the consumption rate of metastable species. Moreover, the discharge uniformity was found positively correlated with the spatial uniformity of seed electron density as well as the seed electron level. The reason for this correlation was explained by the reduction of radial electric field strength and the promotion of seed electron uniformity as pre-ionization level increases. The results obtained in this work may help better understand the pattern formation mechanism of atmospheric helium DBD under the variation of N2 impurity level, thereby providing a possible means of regulating the discharge performance in practical application scenarios. 展开更多
关键词 pattern dielectric barrier DISCHARGE IMPURITIES Penning IONIZATION DISCHARGE UNIFORMITY seed electron
Study on the discharge mechanism and EM radiation characteristics of Trichel pulse discharge in air
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作者 王闯 陈曦 +1 位作者 唐凯 李鹏斐 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期113-120,共8页
The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel p... The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel pulse are studied in the needle-plate electrode configuration.The Trichel pulse currenl and its EM radiation signals are measured at different applied voltages.The results show that Trichel pulse discharge changes from the nindom pulse stage to the continuous pulse stage as the applied voltage increases.During these different stages,the normalized shape of the Trichel pulses remains unchanged,while the frequency of the EM radiation generated by the discharge remains unchanged.The discharge mechanism and EM radiation characteristics of the Trichel pulse are theoretically analyzed in the different stages.Both the positive ion sheath and the negative ion cloud play key roles in the formation of the Trichel pulse.The EM radiati on signal is generated by the rapidly changing Trichel pulse current,and the Trichel pulse current waveform determines the characteristics of the EM radiation signal. 展开更多
关键词 NEGATIVE CORONA DISCHARGE Trichel PULSE EM RADIATION DISCHARGE mechanism
Aerodynamic actuation characteristics of radio-frequency discharge plasma and control of supersonic flow
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作者 杨臻 宋慧敏 +3 位作者 王宏宇 郭善广 贾敏 王康 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期321-330,共10页
In this paper, aerodynamic actuation characteristics of radio-frequency(RF) discharge plasma are studied and a method is proposed for shock wave control based on RF discharge. Under the static condition, a RF diffuse ... In this paper, aerodynamic actuation characteristics of radio-frequency(RF) discharge plasma are studied and a method is proposed for shock wave control based on RF discharge. Under the static condition, a RF diffuse glow discharge can be observed;under the supersonic inflow, the plasma is blown downstream but remains continuous and stable.Time-resolved schlieren is used for flow field visualization. It is found that RF discharge not only leads to continuous energy deposition on the electrode surface but also induces a compression wave. Under the supersonic inflow condition, a weak oblique shock wave is induced by discharge. Experimental results of the shock wave control indicate that the applied actuation can disperse the bottom structure of the ramp-induced oblique shock wave, which is also observed in the extracted shock wave structure after image processing. More importantly, this control effect can be maintained steadily due to the continuous high-frequency(MHz) discharge. Finally, correlations for schlieren images and numerical simulations are employed to further explore the flow control mechanism. It is observed that the vortex in the boundary layer increases after the application of actuation, meaning that the boundary layer in the downstream of the actuation position is thickened. This is equivalent to covering a layer of low-density smooth wall around the compression corner and on the ramp surface, thereby weakening the compressibility at the compression corner. Our results demonstrate the ability of RF plasma aerodynamic actuation to control the supersonic airflow. 展开更多
关键词 radio-frequency(RF) DISCHARGE PLASMA surface DISCHARGE FLOW control aerodynamic ACTUATION
Relation between etching profile and voltage-current shape of sintered SiC etching by atmospheric pressure plasma
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作者 D C SEOK S R YOO +2 位作者 K I LEE Y S CHOI Y H JUNG 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期137-144,共8页
Sintered silicon carbide(SiC)was etched by a dielectric barrier discharge source.A high voltage bipolar pulse was used with helium gas for the plasma generation.One stable filament plasma was generated and could be us... Sintered silicon carbide(SiC)was etched by a dielectric barrier discharge source.A high voltage bipolar pulse was used with helium gas for the plasma generation.One stable filament plasma was generated and could be used for SiC etching.As the processing gas(NF3)mixing rate increased,the width and depth of the etching profile became narrower and deeper.The differentiated V-Q Lissajous method was used for measuring the capacitances(Ceq)of the electrode after the plasma turned on.The width of the etching profile was proportional to Ceq.As the current peak value/smx of the substrate current in creased,the volume removal rate of SiC increased.The etch depth was proportional to the ratio of/smx to Ceq.Additionally,because of the different characteristics of the plasma disks on SiC substrate by the voltage polarity,the etching profile was unstable.However,in high NF3 mixing process,the etching profile became stable and deeper. 展开更多
关键词 dielectric BARRIER DISCHARGE silicon CARBIDE plasma etching、filament discharge surface CHARGE
Applying the Distributed Hydrological Model for Tropical Monsoon Basins by Using Earth Observation Data (Case Studies: Kone and Ba River Basins) 预览
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作者 Phan Thi Thanh Hang 《地球科学和环境保护期刊(英文)》 2019年第1期23-37,共15页
Due to the limitation of data sources, the application of Distributed Hydrological Models (DHMs) using earth observation data to research water resources is necessary. In this study, the BTOPMC (Block-wise use of TOPM... Due to the limitation of data sources, the application of Distributed Hydrological Models (DHMs) using earth observation data to research water resources is necessary. In this study, the BTOPMC (Block-wise use of TOPMODEL) model was applied for 2 basins in the tropical monsoon region. This is the first time that the land cover map of the CCI (Climate Change Initiative Land Cover Team) was prepared for input data instead of IGBP (International Geosphere-Biosphere Programme) land cover map as proposed in the demo version of the BTOPMC model. The calibration and validation results showed that the Nash-Sutcliffe coefficients for daily stream discharge were 77.5% and 68.7% at Cung Son station (Ba basin). The Nash-Sutcliffe coefficients for daily stream discharge were 79.4% and 69.0% at Binh Tuong station (Kone basin), respectively. Because of a stop in measuring the discharge at Binh Tuong station in 2007, this model was applied to simulate discharge during the period of 2008-2015. Furthermore, the effect of land cover on discharge at Cung Son station was considered. The annual discharge in 2010 at Cung Son decreased 8 m3/s in the comparison between two scenarios (land cover of 2000 and 2010). According to this result, it is possible to propose a wide application range of the DHMs model to the tropical monsoon river basins using earth observation data. 展开更多
关键词 Distributed HYDROLOGICAL Model TROPICAL MONSOON DISCHARGE Land COVER Earth Observation Data
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Experimental study on nanosecond pulsed pin-to-plate discharge in supersonic air flow
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作者 李益文 庄重 +3 位作者 庞磊 段朋振 丁志文 张百灵 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第6期122-131,共10页
Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic a... Development of magnetohydrodynamic acceleration technology is expected to improve wind tunnel simulation capability and testing capability.The underlying premise is to produce uniform and stable plasma in supersonic air flow,and gas discharge is an effective way to achieve this.A nanosecond pulsed discharge experimental system under supersonic conditions was established,and a pin-to-plate nanosecond pulsed discharge experiment in Mach 2 air flow was performed to verify that the proposed method produced uniform and stable plasma under supersonic conditions.The results show that the discharge under supersonic conditions was stable overall,but uniformity was not as good as that under static conditions.Increasing the number of pins improved discharge uniformity,but reduced discharge intensity and hence plasma density.Under multi-pin conditions at 1000Hz,the discharge was almost completely corona discharge,with the main current component being the displacement current,which was smaller than that under static conditions. 展开更多
关键词 nanosecond pulse DISCHARGE SUPERSONIC air flow pin-to-plate DISCHARGE plasma UNIFORM and stable
Evaluation on a double-chamber gas-liquid phase discharge reactor for benzene degradation
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作者 商克峰 张琦 +3 位作者 鲁娜 姜楠 李杰 吴彦 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第7期135-144,共10页
A double-chamber gas-liquid phase DBD reactor(GLDR), consisting of a gas-phase discharge chamber and a gas-liquid discharge chamber in series, was designed to enhance the degradation of benzene and the emission of NOx... A double-chamber gas-liquid phase DBD reactor(GLDR), consisting of a gas-phase discharge chamber and a gas-liquid discharge chamber in series, was designed to enhance the degradation of benzene and the emission of NOx. The performance of the GLDR on discharge characteristics,reactive species production and benzene degradation was compared to that of the single-chamber gas phase DBD reactor(GPDR). The effects of discharge gap, applied voltage, initial benzene concentration, gas flow rate and solution conductivity on the degradation and energy yield of benzene in the GLDR were investigated. The GLDR presents a higher discharge power, higher benzene degradation and higher energy yield than that of the GPDR. NO2 emission was remarkably inhibited in the GLDR, possibly due to the dissolution of NO2 in water. The benzene degradation efficiency increased with the applied voltage, but decreased with the initial concentration, gas flow rate, and gas discharge gap, while the solution conductivity presented less influence on benzene degradation. The benzene degradation efficiency and the energy yield reached 61.11% and 1.45 g k Wh-1 at 4 mm total gas discharge gap, 15 k V applied voltage, 200 ppm benzene concentration,0.2 L min-1 gas flow rate and 721 μS cm-1 water conductivity. The intermediates and byproducts during benzene degradation were detected by FT-IR, GC-MS and LC-MS primarily, and phenols,COx, and other aromatic substitutes, O3, NOx, etc, were determined as the main intermediates.According to these detected byproducts, a possible benzene degradation mechanism was proposed. 展开更多
关键词 dielectric barrier DISCHARGE GAS-LIQUID hybrid DISCHARGE BENZENE DEGRADATION REACTIVE species nitrogen dioxide
Characteristics and underlying physics of ionic wind in dc corona discharge under different polarities
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作者 张桐恺 张宇 +2 位作者 季启政 李犇 欧阳吉庭 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第7期324-332,共9页
During a dc corona discharge, the ions’ momentum will be transferred to the surrounding neutral molecules, inducing an ionic wind.The characteristics of corona discharge and the induced ionic wind are investigated ex... During a dc corona discharge, the ions’ momentum will be transferred to the surrounding neutral molecules, inducing an ionic wind.The characteristics of corona discharge and the induced ionic wind are investigated experimentally and numerically under different polarities using a needle-to-ring electrode configuration.The morphology and mechanism of corona discharge, as well as the characteristics and mechanism of the ionic wind, are different when the needle serves as cathode or anode.Under the different polarities of the applied voltage, the ionic wind velocity has a linear relation with the overvoltage.The ionic wind is stronger but has a smaller active region for positive corona compared to that for negative corona under a similar condition.The involved physics are analyzed by theoretical deduction as well as simulation using a fluid model.The ionic wind of negative corona is mainly affected by negative ions.The discharge channel has a dispersed feature due to the dispersed field, and therefore the ionic wind has a larger active area.The ionic wind of positive corona is mainly affected by positive ions.The discharge develops in streamer mode, leading to a stronger ionic wind but a lower active area. 展开更多
关键词 CORONA DISCHARGE IONIC wind ELECTRODE polarity
The effects of gas flow pattern on the generation of ozone in surface dielectric barrier discharge
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作者 谢松汝 何勇 +4 位作者 袁定琨 王智化 Sunel KUMAR 朱燕群 岑可法 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期168-178,共11页
Ozone production utilizing surface dielectric barrier discharge(SDBD)was experimental studied for different flow patterns considering the influences of transversal flow,lateral flow and different lateral flow position... Ozone production utilizing surface dielectric barrier discharge(SDBD)was experimental studied for different flow patterns considering the influences of transversal flow,lateral flow and different lateral flow positions.Results show that the flow patterns have a remarkable impact on the ozone yield by affecting the uniformity and turbulenee of gas flow.Meanwhile,distributing the O2 flow rate according to the intensity of the plasma reaction would also increase the generation efficiency of SDBD for ozone production.By improving the uniformity and introducing the lateral flow to the transversal flow,the highest ozone yield was obtained in flow pattern'F‘.In this case,the ozone yield increased by 28.4%to 131 g kWh^-1 from 102.8 g kWh^-1 in flow pattern‘A’. 展开更多
关键词 surface DIELECTRIC BARRIER DISCHARGE gas flow OZONE generation
Thermodynamic Analysis of a Modified Ejector-Expansion Refrigeration Cycle with Hot Vapor Bypass
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作者 LI Yunxiang YU Jianlin 《热科学学报:英文版》 SCIE EI CAS CSCD 2019年第4期695-704,共10页
In this study,a modified ejector-expansion refrigeration cycle(MERC)is proposed for applications in small refrigeration units.A vapor bypass circuit is introduced into the standard ejector expansion refrigeration cycl... In this study,a modified ejector-expansion refrigeration cycle(MERC)is proposed for applications in small refrigeration units.A vapor bypass circuit is introduced into the standard ejector expansion refrigeration cycle(ERC)for increasing the ejector pressure lift ratio,thereby lowering the compressor pressure ratio in the MERC.A mathematical model has been established to evaluate the performances of MERC.Analysis results indicate that since a two phase vapor-liquid stream is used to drive the ejector in the MERC,a larger ejector pressure lift ratio can be achieved.Thus,the compressor pressure ratio decreases by 21.1%and the discharge temperature reduces from 93.6℃to 82.1℃ at the evaporating temperature of-55℃ when the vapor quality of two phase vapor-liquid stream increases from 0 to 0.2.In addition,the results show that the higher ejector component efficiencies are effective to reduce the compressor pressure ratio and the discharge temperature.Actually,the discharge temperature reduces from 91.4℃ to 82.1℃ with the ejector component efficiencies increasing from 0.75 to 0.85 at the two phase stream vapor quality of 0.2.Overall,the proposed cycle is found to be feasible in lower evaporating temperature cases. 展开更多
关键词 COMPRESSOR pressure ratio DISCHARGE temperature EJECTOR REFRIGERATION cycle vapor BYPASS
Breakdown characteristics of CF3I/N2/CO2 mixture in power frequency and lightning impulse voltages
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作者 林启明 赵谡 +1 位作者 肖登明 周柏杰 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第1期36-43,共8页
Trifluoroiodomethane(CF3I) and its mixtures are believed to be prospective alternatives to sulfur hexafluoride(SF6), which has been included as a greenhouse gas. In this paper, the breakdown properties of a CF3I/N2/CO... Trifluoroiodomethane(CF3I) and its mixtures are believed to be prospective alternatives to sulfur hexafluoride(SF6), which has been included as a greenhouse gas. In this paper, the breakdown properties of a CF3I/N2/CO2 mixture with the volume fraction of CF3I fixed at 10% are investigated under power frequency and lightning impulse voltages. The experimental result shows that N2 possesses higher power frequency and negative lightning impulse breakdown voltages than CO2, but the power frequency and more negative lightning impulse breakdown voltages of the CF3I/N2/CO2 mixture do not increase with the content of N2. For the purpose of explaining this abnormal phenomenon, the ionization energies and excitation energies of CF3I,N2and CO2 are calculated. The computation results indicate that the ionization energy of CF3I is lower than the first excitation energy of N2, but higher than the lowest excitation energy of CO2,which means that CF3I molecules are easily ionized by metastable N2 molecules. The first excitation energy of N2 is too high, which hinders its application as the buffer gas of CF3I. 展开更多
关键词 GAS DISCHARGE CF3I GAS MIXTURES Penning EFFECT BUFFER GAS
A comparison of emissive and cold floating probe techniques for electric potential measurements in rf inductive discharge
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作者 Yaroslav MURZAEV Gen nadii LIZIAKIN +2 位作者 An drey GAVRIKOV Rinat TIMIRKHANOV Valentin SMIRNOV 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期94-98,共5页
A cold floating probe method was compared with the emissive floating probe method in terms of a low-pressure radio-frequency inductive discharge.The dependences of difference between the plasma potential and the float... A cold floating probe method was compared with the emissive floating probe method in terms of a low-pressure radio-frequency inductive discharge.The dependences of difference between the plasma potential and the floating potential on the electron temperature 1-8 eV,plasma density 109-1012 cm 3 and magnetic field 100-650 G were obtained.It was demonstrated that the difference between the potentials that obtained by these two methods can differ significantly from the expected value of 5.2 kTe/e for argon. 展开更多
关键词 emissive PROBE FLOATING PROBE rf INDUCTIVE DISCHARGE plasma potential measurement
Detecting Deterioration Stages in Epoxy Resins Specimens under Partial Discharge Process 预览
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作者 Cristian R.Bonini Marcos U.Maillot Franco M.Pessana 《电气工程:英文版》 2019年第2期39-50,共12页
This paper presents a novel analysis tool based on partial discharge(PD)pulses waveform to determinate deterioration process as the fault evolves carbonizing the insulating medium in epoxy resin specimens.The PD pulse... This paper presents a novel analysis tool based on partial discharge(PD)pulses waveform to determinate deterioration process as the fault evolves carbonizing the insulating medium in epoxy resin specimens.The PD pulses were acquired in the laboratory under controlled conditions;specially designed specimens were tested with a tip-flat electrode configuration immersed in a thermostable polymer(epoxy resin).Then,in the processing step,all acquired PD pulses were characterized with the Shannon entropy,and its variations along the deterioration process were studied.It was observed that the dispersion of this quantity increases with the deterioration of the medium,which allowed identifying different deterioration stages.The evolution of the deterioration has a correlation with the appearance of a greater number of pulses,whose entropy values diverge from average value(close to 2).These new pulses were analyzed using signal processing tools.It was found that there are important differences in the spectral content of each family,in the time-scale characteristics and in the energy distribution of the same frequency bands corresponding to each pulses family.In this work,the deterioration of epoxy resin specimens was characterized throughout the modifications observed in the characteristics of PD pulses during the entire failure process.It could be verified that there is information about the deterioration of the medium contained in the characteristics of the analyzed pulses. 展开更多
关键词 PARTIAL discharge entropy EPOXY resin WAVELET transform
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渤海油田普通稠油冷采测试工艺 预览 被引量:1
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作者 高科超 高飞 +2 位作者 杨子 杨歧年 刘宝坤 《油气井测试》 2019年第1期38-45,共8页
针对渤海油田稠油井测试过程中存在的出砂、垂直管流黏阻大流动困难、PVT取样成功率低、计量误差大等难题,从射孔、防砂、控温、取样及计量工艺优化等方面细化研究,形成了由稳岩控砂射孔诱喷技术、井下测试管柱控温技术、稠油PVT取样技... 针对渤海油田稠油井测试过程中存在的出砂、垂直管流黏阻大流动困难、PVT取样成功率低、计量误差大等难题,从射孔、防砂、控温、取样及计量工艺优化等方面细化研究,形成了由稳岩控砂射孔诱喷技术、井下测试管柱控温技术、稠油PVT取样技术和稠油测试配套计量技术组成的普通稠油井冷采测试工艺。该工艺采用大孔径、深穿透、高密度射孔技术配合合适的诱喷压差提高油层渗流能力,联合井筒保温和加热技术降低原油在井筒中的流动阻力,优化取样器放置位置和取样时机,采用具有压力补偿功能的单相取样器保证取样准确性,配备可加热式的25m^3计量罐实现精确计量。渤海油田蓬莱31-X1井现场应用表明,取样压差仅为0.925MPa,取样合格;采用螺杆泵排液求产,80r/min时日产油52.84m^3,130r/min时日产油89.28m^3;四次开关井均取得了合格的压力数据资料。该工艺为类似稠油油田产能释放及有效动用提供了技术支撑。 展开更多
关键词 渤海油田 普通稠油 试采 射孔 控温 取样 计量 排液
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Electrical and optical characteristics of atmospheric helium jet array plasma
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作者 柳晶晶 陈东 +1 位作者 莫益健 荣一 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第11期38-44,共7页
In this paper,a honeycomb structure jet array with seven jet units was adopted to generate plasmas.Both the average discharge power and the emission intensity of the main excited species increase with increasing appli... In this paper,a honeycomb structure jet array with seven jet units was adopted to generate plasmas.Both the average discharge power and the emission intensity of the main excited species increase with increasing applied voltage.There are three stages of discharge evolution at different applied voltages:initial discharge,uniform discharge and strong coupling discharge.The spatial distribution of the emission intensity of the excited species can be divided into three categories:growth class,weakening class and variation class.The gas temperature along the whole plasma plume at different applied voltages is maintained at around 320 K and can be widely used in heat-labile applications. 展开更多
关键词 JET ARRAY PLASMA DISCHARGE evolution spatial distribution heat-labile application
Three decades of changes in water environment of a large freshwater Lake and its relationship with socio-economic indicators
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作者 Cuicui Li Weiying Feng +5 位作者 Fanhao Song Zhongqi He Fengchang Wu Yuanrong Zhu John P.Giesy Yingchen Bai 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第3期156-166,共11页
Tai Lake(Ch: Taihu) has attracted international attention forcyanobacteria blooms.However, the drivers of cultural eutrophication, especially long-term socio-economic indicators have been little researched. The result... Tai Lake(Ch: Taihu) has attracted international attention forcyanobacteria blooms.However, the drivers of cultural eutrophication, especially long-term socio-economic indicators have been little researched. The results of research demonstrate how socioeconomic development affected quality of water and how it has been improved by anthropogenic activities. This study described variability in indicators of water quality in Tai Lakeand investigated thedrivers. Significant relationships existed between concentrations of annual mean total nitrogen(TN), total phosphorous(TP), chemical oxygen demand(COD) and biological oxygen demand(BOD), and population, per capital gross domestic production(GDP) and sewage discharge(p < 0.05). However, mechanisms causing change varied among TN, TP, COD and BOD. Before 2000, the main contributors to increases in concentrations of TN were human population, GDP and volumes of domestic sewage discharges. After 2000, discharges of industrial sewage become the primary contributor. After 1998, the regressions of annual mean TN, TP and COD on per capital GDP, population and domestic sewage discharge were reversed compared to the former period. Since 1999, an apparent inverted U-shaped relationship between environmental pollution and economic development has developed, which indicated that actions taken by governments have markedly improved quality of water in Tai Lake. The statistical relationship between BOD and per capital GDP didn’t conform to the Kuznet curve. The Ushaped Kuznet curve may offer hope for the future that with significant environmental investments a high GDP can be reached and maintained without degradation of the environment, especially through appropriate management of industrial sewage discharge. 展开更多
关键词 EUTROPHIC LAKE Water environment INDICATORS Population GDP SEWAGE discharge Asia
Effect of glow discharge on hypersonic flat plate boundary layer 预览
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作者 Chi LI Yunchi ZHANG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第2期249-260,共12页
Glow discharge is introduced as an artificial disturbance to investigate the evolution of first-and second-mode instabilities in a hypersonic flat plate boundary layer.Experiments are conducted in a Mach 6.5 quiet win... Glow discharge is introduced as an artificial disturbance to investigate the evolution of first-and second-mode instabilities in a hypersonic flat plate boundary layer.Experiments are conducted in a Mach 6.5 quiet wind tunnel using Rayleigh scattering visualization and particle image velocimetry(PIV).Detailed analysis of the experimental observations is provided.It is found that the artificially introduced 17 kHz disturbance,which belongs to the first-mode frequency band,can effectively enhance first-mode waves.Moreover,it can enhance second-mode waves even more intensely.Possible mechanisms to explain this phenomenon are discussed. 展开更多
关键词 GLOW DISCHARGE HYPERSONIC particle image velocimetry(PIV)
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Influence of dust particles on spatial distributions of particles and fluxes in positive column of glow discharge
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作者 田瑞焕 袁承勋 +3 位作者 Dmitrii V BOGDANOV Evgeniy A BOGDANOV Anatoly A KUDRYAVTSEV 周忠祥 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第11期45-54,共10页
The research herein examined the results of numerical simulations of the positive column of a glow discharge in argon dusty plasma using COMSOL Multiphysics software under conditions similar to the project known as PK... The research herein examined the results of numerical simulations of the positive column of a glow discharge in argon dusty plasma using COMSOL Multiphysics software under conditions similar to the project known as PK-4.Various scenarios dealing with formations of spatial distributions of densities and fluxes for charged particles were studied,and evaluations of the influence of dust particles on the discharge were obtained in a wide range of dust densities.Two extreme cases were distinguished:weak dust influence when the densities,fluxes and electric field profiles are not perturbed,and strong dust influence when all three density profiles(electrons,ions and charged dust)in the dust cloud are similar(parallel)to each other,resulting in all created charges in the dust cloud being lost inside the cloud.In such a case,the ambipolar field and the transport of charged particles are decreased in the dust cloud,and any ambipolar flux is almost absent within the cloud. 展开更多
关键词 DUSTY plasma GLOW discharge kinetics modeling SCALING LAWS
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