• Title/Summary/Keyword: Plasma

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The Characteristics of Microwaves in the Plasma Medium (프라스마내의 마이크로파 특성)

  • 양인용;강형목
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.2 no.2
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    • pp.2-8
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    • 1965
  • This paper shows the characteristics of microwaves in a plasma medium bounded by a waveguide. A standing wave detector which has VSWR less than 1.05 is designed and constructed. The electromagnetic waves which propagate through the plasma is reflected partly by the interaction between the external magnetic fields and plasma. The plasma is consisted of the electrons and positive ions ionized by high temperature of tungsten filament inserted in the waveguide. The transmitted power through the plasma was reduced by the amount of 1.5db from the reference.

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섬유의 Plasma 가공(I) -plasma 처리화학-

  • 광진민박;조환
    • Textile Coloration and Finishing
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    • v.3 no.3
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    • pp.44-56
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    • 1991
  • 진공하에서 일어나는 glow 방전을 이용해서 행하는 plasma 반응은, 표면 특이적(Surface specific)인, 또는 비파괴적인 처리공정(Non-destructive process) 으로서 주목되고 있는 기술이다. 전반은 plasma chemistry로서, 섬유가공의 기초가 되는 plasma를 이용한 반응에 대하여 정리한다. 또 다음 후반에는 섬유가공에 관한 응용예에 대해서, 특히, 최근 실용화를 이룩하고 있는 일본에 있어서의 plasma 응용의 연구개발들, polyester 섬유염색물의 농색화가공, 양모직물의 방축가공 등의 기술동향 및 실용화를 위한 장치개발 등을 소개코자 한다.

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Mass and energy of erupting plasma associated with a coronal mass ejection in X-rays and EUV

  • Lee, Jin-Yi;Raymond, John C.;Reeves, Katharine K.;Moon, Yong-Jae;Kim, Kap-Sung
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.85.1-85.1
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    • 2015
  • We investigate the mass and energy of erupting plasma observed in X-rays and EUV, which is associated with a coronal mass ejection (CME) and an X-class flare. The erupting plasma was observed by both the X-ray telescope (XRT) on Hinode and the Atmospheric Imaging Assembly (AIA) on Solar Dynamic Observatory (SDO). We estimate the emission measures of the erupting plasma using a differential emission measure method. The plasma erupts with a loop-like structure in X-ray and EUV. We estimate the mass of erupting plasma assuming a cylinder structure. In addition, we estimate the radiative loss, thermal conduction, thermal, and kinetic energies of the eruptive hot plasma. We find that the thermal conduction timescale is much shorter than the duration of the eruption. This result implies that additional heating during the eruption may be required to explain the hot plasma observations in X-rays.

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BLOOD PLASMA MINERALS AND FERTILITY OF DAIRY COWS IN CENTRAL THAILAND

  • Vijchulata, P.
    • Asian-Australasian Journal of Animal Sciences
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    • v.8 no.3
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    • pp.263-265
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    • 1995
  • Blood plasma minerals and their effects towards the fertility in 136 cows randomly selected from 26 dairy farms in central Thailand were studied. An average of 8.60 mg% Ca, 5.97 mg% P, 2.45 mg% Mg, $85.9{\mu}g%$ Cu, and $160.9{\mu}g%$ Zn in plasma was observed. Compared to the critical deficient values, 24.3, 10.3, 11.8, 28.7 and 0.0% of the surveyed cows obtained the respective elements in plasma below the standard levels. No significant difference (p >.05) in plasma concentrations of Ca, P, Mg and Zn for the low fertile (conception rate > 3) and fertile (conception rate < 3) cows was found. However, plasma Cu of the low fertile cows (averaged $77.2{\mu}g%$) was lower (p <.01) than that of the fertile ones (averaged $91.12{\mu}g%$). Additionally, it is observed that 47.1% of the cows with the low fertility problem obtained plasma Cu below the 65.0 pg% critical deficient value.

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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    • 2015.08a
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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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Sintering Phenomena and Thermodynamic Analysis in the SiC Whisker-Reinforced Mullite Matrix Ceramic Composites During RF Plasma Sintering

  • Park, Youngsoo;:Michael J. MeNallan
    • The Korean Journal of Ceramics
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    • v.2 no.4
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    • pp.231-237
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    • 1996
  • Mullite ceramics can be sintered by rf plasma sintering to densities as high as 97% compared to the theoretical density of the mullite, while SiC whisker-reinforced mullite matrix ceramic composites were not sintered by plasma sintering. Decomposition of mullite occurs in a superficial regins at the outside surface of the specimen by volatilization of SiO at elevated temperature by plasma. SiC whiskers were destroyed, and the matrix was converted to alumina from SiC-whisker reinforced mullite matrix ceramic composites during the plasma sintering. Accelerated volatilization from the SiC whisker in the mullite prevents sintering. The volatile species are mainly SiC and CO gas species. The effects of plasma on mullite and SiC-whisker reinforced mullite matrix composites are interpreted by thermodynamic simulation of the volatile species in the plasma environment. The thermodynamic results show that the decomposition will not occur during hot pressing.

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