• Title/Summary/Keyword: arc-discharge

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Analysis of reactive species in water activated by plasma and application to seed germination

  • Choi, Ki-Hong;Lee, Han-Ju;Park, Gyungsoon;Choi, Eun-Ha
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.162.1-162.1
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    • 2015
  • The use of plasma has increased in bio-application field in recent years. Particularly, water treated by arc discharge or atmospheric pressure plasma has been actively utilized in bio-industry. In this study, we have developed a plasma activated water generating system. For this system, two kinds of plasma sources; dielectric barrier discharge (DBD) plasma and arc discharge plasma have been used. The discharge energy was calculated using the breakdown voltage and current, and the emission spectrum was measured to investigate the generated reactive species. We also analyzed the amount of reactive oxygen and nitrogen species in water using the chemical methods and nitric oxide sensor. Finally, the influence of plasma generated reactive species on the germination and growth of spinach (Spinacia oleracea) was investigated. Spinach is a green leafy vegetable that contains a large amount of various physiologically active organic compounds. However, it is characterized with a low seed germination rate.

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Duplex Surface Modification with Micro-arc Discharge Oxidation and Magnetron Sputtering for Aluminum Alloys

  • Tong, Honghui;Jin, Fanya;He, Heng
    • Journal of the Korean Vacuum Society
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    • v.12 no.S1
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    • pp.21-27
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    • 2003
  • Micro-arc discharge oxidation (MDO) is a cost-effective plasma electrolytic process which can be used to improve the wear and corrosion resistance of Al-alloy parts by forming a alumina coating on the component surface. However, the MDO coated Al-alloy components often exhibit relatively high friction coefficients and low wear resistance fitted with many counterface materials, additionally, the pitting corrosion for the MDO coated AI-alloy components, especially for a thinner alumina coating, often occurs in atmosphere circumstance due to the porous alumina coats. Therefore, a duplex treatment, combining a MDO coated ahumina thin layer with a TiN coating, prepared by magnetron sputtering (MS), has been investigated. The Vicker's microhardness, pin-on-disc, electrochemical measurement, salt spray, XRD and SEM tests were used to characterize and analyze the treated samples. The work demonstrates that the MDO/MS coated samples have a combination of a very low friction coefficient and good wear resistance as well as corrosion since the micro-holes on alumina coating are partly or fully covered by TiN material.

Preparation and Sintering Behavior of Fe Nanopowders Produced by Plasma Arc Discharge Process

  • Choi, Chul-Jin;Yu, Ji-Hun
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.284-285
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    • 2006
  • The nano-sized Fe powders were prepared by plasma arc discharge process using pure Fe rod. The microstructure and the sintering behavior of the prepared nanopowders were evaluated. The prepared Fe nanopowders had nearly spherical shapes and consisted of metallic core and oxide shell structures. The higher volume shrinkage at low sintering temperature was observed due to the reduction of surface oxide. The nanopowders showed 6 times higher densification rate and more significant isotropic shrinkage behavior than those of micron sized Fe powders.

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Synthesis of Ultrafine Zr Based Alloy Powder by Plasma Arc Discharge Process

  • Lee, Gil-Geun;Park, Je-Shin;Kim, Won-Baek
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.420-421
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    • 2006
  • In the present study, ultrafined Zr-V-Fe based alloy powder prepared by a plasma arc discharge process with changing process parameters. The chemical composition of synthesized powder was strongly influenced by the process parameters, especially the hydrogen volume fraction in the powder synthesis atmosphere. The synthesized powder had an average particle size of 50 nm. The synthesized Zr-V-Fe based particles had a shell-core structure composed of metal in the core and oxidse in the shell.

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A study on the arc discharge characteristics of liquid insulating materials for electrical discharge machine (방전가공기용 액체 절연재료의 아크 방전 특성 연구)

  • 김상현;김해종;마대영;신태민
    • Electrical & Electronic Materials
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    • v.8 no.5
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    • pp.564-571
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    • 1995
  • This paper deals with the arc discharge characteristics of kerosene oil as a basic study on electrical discharge machine. Using needle electrode the discharge voltage, discharge current, discharge energy and the shape of discharge crater are measured. In consequence, it becomes clear that the discharge crater(depth, height, diameter) is depending on the discharge energy. Rapid increase in depth, height and diameter of discharge crater was observed during initial discharge, where discharge energy is large. However, rather slow decrease of those values was found when discharge energy is low or N is more than 3. As the ratio of $I_p$$T_on$ increase, the shape of discharge crater gets near circle. The protuberances of the discharge crater were not formed by the melted needle electrode but by the that of work piece.

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A Study on Tracking Degradation Properties of Silicone Rubber due to Reinforcing Agent (보강제 변화에 따른 실리콘 고무의 트래킹 열화 특성에 관한 연구)

  • Lee, Sung Ill
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.12
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    • pp.841-846
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    • 2014
  • It found that the maximum temperature of the arc discharge occurred on the Silicone rubber sample significantly decreased with increasing the reinforcing agent. It was confirmed that the current value decreased with increasing the aluminium trihydrate($Al(OH)_3$) and the current value increased with reducing the primary resistance over time. Regarding these results, may be it is because the degradation due to the electro-conductive carbonization was improved and the properties of dielectric breakdown was reduced by the flame retardant reinforcing agent. It found that the electro-conductive carbonized road has not happened by increasing the flame retardant reinforcing agent. Regarding to the arc discharge, this study show that the arc arising near the lower electrode of sample has disappeared.

Characterization of Fe Nanocapsules synthesized by Plasma Arc Discharge Process (플라즈마 아크방전(PAD)법으로 제조된 Fe Nanocapsules의 특성)

  • Park Woo-Young;Youn Cheol-Su;Yu Ji-Hun;Oh Young-Woo;Choi Chul-Jin
    • Journal of Korean Powder Metallurgy Institute
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    • v.11 no.6
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    • pp.510-514
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    • 2004
  • Iron-carbon nanocapsules were synthesized by plasma arc discharge (PAD) process under various atmosphere of methane, argon and hydrogen gas. Characterization and surface properties were investigated by means of HRTEM, XRD, XPS and Mossbauer spectroscopy. Fe nanocapsules synthesized were composed of three phases $({\alpha}-Fe,\;Y-Fe\;and\;Fe_{3}C)$ with core/shell structures. The surface of nanocapsules was covered by the shell of graphite phase in the thickness of $4{\~}5$nm.

Preparation of FeAl nanopowders by Plasma Arc Discharge Process (플라즈마 아크방전(PAD)법으로 제조된 FeAl 나노분말 특성)

  • Park Woo-Young;Youn Cheol-Su;Yu Ji-Hun;Oh Young-Woo;Choi Chul-Jin
    • Journal of Korean Powder Metallurgy Institute
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    • v.11 no.6
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    • pp.522-527
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    • 2004
  • Nano sized FeAl intermetallic particles were successfully synthesized by plasma arc discharge pro-cess. The synthesized powders shouted core-shell structures with the particle size of 10-20 nm. The core was metallic FeAl and shell was composed of amorphous $AI_{2}O_{3}\;and\;a\;little\;amount\;of\;metallic\;Fe_{3}O_{4}.$ Because of the difference of Fe and Al vapor pressure during synthesis, the Al contents in the nanoparticles depended on the Al contents of master alloy.

Effect of the Process Parameters on the Fe Nano Powder Formation in the Plasma Arc Discharge Process (플라즈마 아크 방전법에서 Fe 나노 분말 형성에 미치는 공정변수의 영향)

  • 이길근;김성규
    • Journal of Korean Powder Metallurgy Institute
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    • v.10 no.1
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    • pp.51-56
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    • 2003
  • To investigate the effect of the parameters of the plasma arc discharge process on the particle formation and particle characteristics of the iron nano powder, the chamber pressure, input current and the hydrogen volume fraction in the powder synthesis atmosphere were changed. The particle size and phase structure of the synthesized iron powder were studied using the FE-SEM, FE-TEM and XRD. The synthesized iron powder particle had a core-shell structure composed of the crystalline $\alpha$-Fe in the core and the crystalline $Fe_3O_4$ in the shell. The powder generation rate and particle size mainly depended on the hydrogen volume fraction in the powder synthesis atmosphere. The particle size increased simultaneously with increasing the hydrogen volume fraction from 10% to 50%, and it ranged from about 45nm to 130 nm.

Effect of Chamber Pressure on the Microstructure of Fe Nano Powders Synthesized by Plasma Arc Discharge Process (플라즈마 아크 방전법으로 제조된 Fe 나노분말의 미세조직에 미치는 챔버압력 영향)

  • 박우영;윤철수;김성덕;유지훈;오영우;최철진
    • Journal of Korean Powder Metallurgy Institute
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    • v.11 no.4
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    • pp.328-332
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    • 2004
  • Fe nanopowders were successfully synthesized by plasma arc discharge (PAD) process using Fe rod. The influence of chamber pressure on the microstructure was investigated by means of X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared particles had nearly spherical shapes and consisted of metallic cores (a-Fe) and oxide shells (Fe$_{3}$O$_{4}$), The powder size increased with increasing chamber pressure due to the higher dissolution and ejection rate of H$_2$ and gas density in the molten metal.