检索结果-南通市图书馆

Photographic Study on spark discharge Generated by a Nanosecond High-Voltage Pulse over a Water Surface

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2013年第10期15卷 1020-1024页

作者：李文琴温小琼张家良 Center for Plasma Science and Engineering School of Physics and Optoelectronic TechnologyDalian University of Technology

spark discharge generated by a nanosecond positive high-voltage pulse over a water surface at atmospheric pressure in air was studied using a high speed camera system. Faint streamers form near the pin electrode and propagate towards the water surface. The time for the streamer propagating across the air gap was estimated to be about 50 ns to 60 ns with a propagation velocity of ～1.3 × 10^5 m/s. It was found that the water conductivity and the gap distance have no significant effect on the propagation velocity of the streamer. After the streamers touch the water surface a brilliant spark channel forms across the air gap. The maximum diameter at the middle of the spark channel is about 1 mm, and approximately contracts with a radical velocity of about 2.0× 10^3 m/s. No significant dependence of the maximum diameter and decay velocity of the spark channel on the water conductivity and the gap distance were recognized in the present work. The maximum conduction current for a gap distance of 5 mm is significantly larger than that for a gap distance of 10 mm at the same water conductivity, and shows an increasing tendency with increasing water conductivity for a fixed gap distance. Based on the maximum conduction current, the effect of water conductivity and gap distance on the electron density of the spark discharge plasma at the peak current was investigated. Within the range studied, the electron density in the spark channel is about 10^15 cm^-3 and increases with water conductivity at a fixed gap distance.

关键词： spark discharge water surface nanosecond high-voltage pulse high speedphotography

Aerodynamic control of NACA 0021 airfoil model with spark discharge plasma synthetic jets

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第11期58卷 1949-1955页

作者： LIU RuBing NIU ZhongGuo WANG MengMeng HAO Ming LIN Qi State Key Laboratory of Aerodynamics China Aerodynamics Research and Development Center School of Physics and Mechanical & Electrical Engineering Xiamen University Fujian Key Laboratory of Plasma and Magnetic Resonance Aerodynamics Research Institute Aviation Industry Corporation of China

spark discharge plasma synthetic jets(SPJs) have been used for the active flow control study on an NACA 0021 straight-wing model in a wind tunnel. The model forces and moments were measured using a six-component sting balance at a 20 m/s wind speed. The aim was to explore the SPJ's effect on airfoil aerodynamic by examining SPJ generators' position along the chordwise and the jet flow direction about the chord. Near the wing leading edge, two SPJ generators raised the stall angle by 2° and increased the maximum lift coefficient by 9%. The drag coefficient was decreased by 33.1%, and the lift-drag ratio was increased by 104.2% at an angle of attack above 16°. The rolling-moment coefficient was modified by 0.002, and the yawing-moment coefficient was changed by 0.0007 at angles of attack in the range of 0°–16°. The results showed that SPJs can control wing aerodynamic forces at a high angle of attack and moments at a low angle of attack.

关键词： plasma synthetic jet spark discharge NACA 0021 airfoil aerodynamic performance aerodynamic control

Spectroscopic Diagnostic of spark discharge Plasma at Atmospheric Pressure

在线全文

学校读者我要写书评

暂无评论

Journal of Chemistry and Chemical Engineering 2014年第3期8卷 302-305页

作者： Laslov Geza Shuaibov Alexander Szegedi Szendor Laszlo Elemer UzhgorodNational University Uzhgorod 88000 Ukraine Department of Meteorology Debrecen Institute of Earth Sciences Faculty of Science and Technology University of Debrecen Debrecen 4027 Hungary

The emission of CuInSe2-based spark discharge plasma at atmospheric pressure in air has been investigated by optical emission spectroscopy method. The plasma was formed by action of the high voltage pulse generator （with nanosecond pulse） on the corresponding electrodes （CulnSe2 compound）. The emission characteristics have been obtained for the spark discharge plasma at 3 mm interelectrode distance. It was established that the spark discharge plasma radiation was determined by decay products of the compound from which electrodes were made. The most suitable spectral lines for plasma diagnostics is atomic copper lines in the visible spectrum and atomic indium lines in UV （ultraviolet） and visible spectrum.

关键词： spark discharge optical emission spectroscopy emission characteristic excited states CulnSe_ compound.

Analysis on Non-penetrating Inducing Effect in Plasma Jet Triggering spark Gap discharge

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Analysis on Non-penetrating Inducing Effect in Plasma Jet Tr...

The Optical Diagnosis of Underwater Positive sparks and Corona discharges

第十八届全国等离子体科学技术会议

作者： Weihao TIE Cui MENG Yuting ZHANG Qiao Gen ZHANG Department of Engineering Physics Tsinghua University

The plasma-jet triggered gas switch(PJTGS) could operate at a low working coefficient with a low *** observed and analyzed the discharge process of the PJTGS at the lowest working coefficient of 45% with the trigger voltage of 40 k V and the pulse energy of 2 J to evaluate the effect of the plasma *** temporal and spatial evolution and the optical emission spectrum of the plasma jet were *** the spraying delay time and outlet velocity under different gas pressures were *** addition,the particle in cell with Monte Carlo collision was employed to obtain the particle distribution of the plasma jet varying with *** results showed that,the plasma jet generated by spark discharge sprayed into a spark gap within tens of nanoseconds,and its outlet velocity could reach 104 m/*** plasma jet plays a non-penetrating inducing role in the triggered discharge process of the *** the one hand,the plasma jet provides the seed electrons needed by the discharge;on the other hand,a large number of electrons focusing on the head of the plasma jet distort the electric field between the head of the plasma jet and the opposite electrode,therefore,a fast discharge originated from the plasma jet is induced and quickly bridges two electrode.

关键词： Gas switch plasma jet spark discharge delay time

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Plasma Science and Technology 2014年第12期16卷 1100-1105页

作者：陈聃曾新吾王一博 College of Opto-Electric Science and Engineering National University of Defense Technology

In this paper, two types of underwater discharges, spark discharge and corona discharge, are investigated by optical diagnosis using a high speed framing camera （HSFC） with the framing time within nanoseconds under the same experimental conditions. In order to capture the photographs of streamer propagation, the influence of the randomicity of the prebreakdown duration is taken into consideration. By increasing the conductivity of water, the randomicity reduces effectively. Experimental results show that, for a spark discharge, the process can be separated into three stages： the generation and propagation of a streamer, the generation and expansion of the discharge channel, and the development and annihilation of the plasma. The streamers do not directly move to the opposite electrode, but form a bush-like figure. With the increase of the number of branches, the velocity of streamer propagation slows down. The trajectory of the initial channel between electrodes is not straight. However, with the channel expanding, its shape transforms into a straight column. For a corona discharge, there are two stages： the generation and propagation of a streamer, and the stagnation and annihilation of the streamer. The initial streamer in a corona discharge is generated later than in a spark discharge. The forms of streamers for both kinds of discharge are similar; however, streamers generated by a corona discharge propagate with a slower velocity and the number of branches is less compared with a spark discharge. When the energy injection stops, the luminescence of plasma inside the discharge channel （spark discharge） or streamers （corona discharge） becomes weaker and weaker, and finally disappears.

关键词： spark discharge corona discharge optical diagnosis HSFC

Effects of the Liquid Conductivity on Pulsed High-voltage discharge Modes in Water

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2004年第10期15卷 1215-1218页

作者： BinYANG LeChengLEI MingHuaZHOU InstituteofEnvironmentalEngineering ZhejiangUniversityHangzhou310027

spark, stream and corona pulsed high-voltage discharges in water induced by the various initial conductivities have been examined in this paper. The discharge modes changed from spark to corona discharge with the liquid conductivity increasing. The apparent production of OH radical and quantum yield generated by spark discharge in distilled water were 11.57 ìmol/L and 0.0978 photon/s, respectively. A preliminary study on acid fuchsine (AF) treatment indicated that higher AF removal efficiency has been achieved by spark discharge. The process of degradation showed that the oxidative effects through OH radical oxidation did not play an important role and did increase with the discharge mode changing to spark discharge.

关键词： Pulsed high-voltage discharge spark discharge corona discharge quantum yields.

Effect of Initial Oxide Film on the Formation and Performance of Plasma Electrolytic Oxidation Coating on 7075 Aluminum Alloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2022年第9期35卷 1559-1571页

作者： Mingyu Zhu Yingwei Song Kaihui Dong Dayong Shan En-Hou Han Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei230026China

In the early stage of plasma electrolytic oxidation(PEO),the quick formation of the initial oxide film on the surface of the aluminum substrate is necessary for the subsequent discharge spark ***,the compactness of the initial oxide film greatly affects the quality of the PEO coating,but the related mechanisms are not investigated in *** this paper,the status of the initial oxide film was adjusted by adding the(NaPO)into the based electrolyte,and then the effect of initial oxide film on the formation of the PEO coating was *** and chemical composition were analyzed by scanning electron microscope,transmission electron microscopy and X-ray photoelectron *** compactness of the initial oxide film was characterized by Mott-Schottky *** corrosion resistance was measured by electrochemical impedance *** results show that the addition of(NaPO)can promote the co-deposition of phosphide compound into the initial oxide film and improve the film compactness,which is beneficial for the more uniform spark discharge in the later *** a result,the addition of(NaPO)is helpful to obtain PEO coating with better performance.

关键词： Aluminum alloys Plasma electrolytic oxidation Initial oxide film Growth process spark discharge Compactness

In-situ characterization of metal nanoparticles and their organic coatings using laser-vaporization aerosol mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Nano Research 2015年第12期8卷 3780-3795页

作者： Patrik T. Nilsson Axel C. Eriksson Linus Ludvigsson Maria E. Messing Erik Z. Nordin Anders Gudmundsson Bengt O. Meuller Knut Deppert Edward C. Fortner Timothy B. Onasch Joakim H. Pagels Ergonomics and Aerosol Technology Lund University P.O. Box 118 Lund SE-22100 Sweden Nuclear Physics Lund University P.O. Box 118 LundSE-22100 Sweden Solid State Physics Lund University P.O. Box 118 Lund SE-22100 Sweden Synchrotron Radiation Research Lund University P.O. Box 118 Lund SE-22100 Sweden Aerodyne Research Inc. Billefica MA 01821-3976 USA

The development of methods to produce nanoparticles with unique properties via the aerosol route is progressing rapidly. Typical characterization techniques extract particles from the synthesis process for subsequent offiine analysis, which may alter the particle characteristics. In this work, we use laser-vaporization aerosol mass spectrometry （LV-AMS） with 70-eV electron ionization for real-time, in-situ nanoparticle characterization. The particle characteristics are examined for various aerosol synthesis methods, degrees of sintering, and for controlled condensation of organic material to simulate surface coating/functionalization. The LV-AMS is used to characterize several types of metal nanoparticles （Ag, Au, Pd, PdAg, Fe, Ni, and Cu）. The degree of oxidation of the Fe and Ni nanoparticles is found to increase with increased sintering temperature, while the surface organic-impurity content of the metal particles decreases with increased sintering temperature. For aggregate metal particles, the organic-impurity content is found to be similar to that of a monolayer. By comparing different equivalent-diameter measurements, we demonstrate that the LV-AMS can be used in tandem with a differential mobility analyzer to determine the compactness of synthesized metal particles, both during sintering and during material addition for surface functionalization. Further, materials supplied to the particle production line downstream of the particle generators are found to reach the generators as contaminants. The capacity for such in-situ observations is important, as it facilitates rapid response to undesired behavior within the particle production process. This study demonstrates the utility of real-time, in-situ aerosol mass spectrometric measurements to characterize metal nanoparticles obtained directly from the synthesis process line, including their chemical composition, shape, and contamination, providing the potential for effective optimization of process operating p

关键词： metal aeroso1 organic surface coating contamination morphology alloy spark discharge

Application of Electrical Means to Aerosol Technologies

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Application of Electrical Means to Aerosol Technologies