• 조명전기설비학회논문지
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• 제22권8호
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• pp.75-81
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• 2008

본 논문은 플라즈마를 이용한 수처리 연구를 수행하였다. 이 연구에 사용한 수중플라즈마 토치는 상당한 전력의 절감을 가져올 수 있기 때문에 경제적인측면과 에너지효율면에서 뛰어난 결과를 나타내었다. 수중에서 일어나는 스트리머방전과 아크방전 현상을 면밀히 조사하여 비교하였고, 또한 염색페수를 플라즈마로 처리하였을 시의 색도제거율과 용존오존, 과산화수소와의 상관관계를 알기위해 표본화하고 분석하였다. 이에 플라즈마토치에는 선택적인 산화반응이 다소 있긴 하지만, 플라즈마화학반응에 의한 $H_2O_2$와 $O_3$의 성장이 아크방전 보다 스트리머방전시 더 효과적으로 촉진된다는 것을 알 수 있었다. 따라서 스트리머방전이 아크플라즈마 토치에 비해 더 효율적인 플라즈마 화학반응을 일으킬 수 있는 환경을 만들어주므로, 수처리에 있어서 스트리머플라즈마토치가 더 적합하였다.

• 한국세라믹학회지
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• 제29권9호
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• pp.681-688
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• 1992

Ultrafine Si3N4 and Si3N4+SiC mixed powders were synthesized through thermal plasma chemical vapor deposition(CVD) using a hybrid plasma, which was characterized by the supersposition of a radio-frequency plasma and arc jet. The reactant SiCl4 was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant CH4 and/or NH3 mixed with H2 were injected into the tail flame through double stage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction efficiency increased significantly by double stage injection compared to single stage one, although crystallizing behaviors depended upon injection speed of reactive quenching gas (NH3+N2) and injection method. For the preparation of Si2N4+SiC mixed powders, N/C composition ratio could be controlled by regulating the injection speed of NH3 and/or CH4 reactant and H2 quenching gas mixtures as well as by adjusting the reaction space.

• Nuclear Engineering and Technology
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• 제56권1호
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• pp.70-77
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• 2024

A low energy ion irradiation system based on the deuterium arc ion source with a high perveance of 1 µP for a single extraction aperture has been successfully developed for the investigation of ion irradiation on plasma-facing components including the first mirror of plasma optical diagnostics system. Under the optimum operating condition for mirror testing, the ion source has a beam energy of 200 eV and a current density of 3.7 mA/cm². The ion source comprises a magnetic cusp-type plasma source, an extraction system, a target system with a Faraday cup, and a power supply control system to ensure stable long time operation. Operation parameters of plasma source such as pressure, filament current, and arc power with D₂ discharge gas were optimized for beam extraction by measuring plasma parameters with a Langmuir probe. The diode electrode extraction system was designed by IGUN simulation to optimize for 1 µP perveance. It was successfully demonstrated that the ion beam current of ~4 mA can be extracted through the 10 mm aperture from the developed ion source. The target system with the Faraday cup is also developed to measure the beam current. With the assistance of the power control system, ion beams are extracted while maintaining a consistent arc power for more than 10 min of continuous operation.

• 치위생과학회지
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• 제9권5호
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• pp.525-530
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• 2009

이 연구는 35% 과산화요소를 이용한 전문가 치아미백술에 플라즈마 아크를 함께 적용하여 플라즈마 아크가 법랑질의 색조변화에 미치는 효과와 비커스경도와 주사전자현미경을 이용하여 법랑질 표면에 미치는 영향을 알아보고자 in vitro 평가를 시행하여 다음과 같은 결론을 얻었다. 1. 미백 횟수의 증가에 따라 색조변화량(${\Delta}E^*$)이 통계적으로 유의한 증가를 나타내었으며, 미백 제만 단독으로 적용한 대조군 보다 플라즈마 아프를 함께 적용하여 미백처리를 한 실험군의 색조변화량(${\Delta}E^*$)이 더 높게 나타나는 것을 알 수 있었다. 2. 미백처리 전 후 법랑질의 미세경도 측정 값을 분석한 결과 미백 처치를 함으로써 미세경도 값이 통계적으로 유의하게 감소되었고, 미백제에 플라즈마 아크를 함께 적용한 실험군에서 더 큰 미세경도의 감소가 나타나는 것을 알 수 있었다. 3. 주사전자현미경 관찰에서 미백 처치를 한 시료에서 법랑질 표면이 상당히 거칠어진 양상을 나타내는 것을 볼 수 있었다. 이상의 결과를 종합해 볼 때 전문가 치아미백술에서 플라즈마 아크를 함께 적용함으로써 색조변화를 더욱 상승시킬 수 있으나, 법랑질 표면의 미세경도와 형태변화를 증가시킬 수 있으므로 미백 효과는 증가시키면서 법랑질의 형태와 구조는 변화시키지 않는 안전한 미백 방법에 관한 연구가 이루어 져야 할 것으로 사료된다.

• 한국분말재료학회지
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• 제11권6호
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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.

• 한국분말재료학회지
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• 제11권6호
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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.

• 한국분말재료학회지
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• 제10권1호
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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.

• 한국분말재료학회지
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• 제11권4호
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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.

• 한국기계가공학회지
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• 제6권3호
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• pp.92-97
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• 2007

The overlay welding the automobile where the durability is demanded, it is used in the vessel engine valve, plant valve and pump parts. Cause of damage public opinion one what is thought is the fatigue load due to the opening and shutting operation right time repetition of the engine valve. The damage cause of the engine valve or explanation of destruction mechanism is very difficult. The research which it sees to make clear a overlay welding of Co-alloy by Plasma Transferred Arc Weld Surfacing Process reconsideration fatigue crack initiation and fatigue crack growth mechanism at high temperature.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1898-1900
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• 1996

The Laser aided diagnostic method makes it possible to diagnose plasma characteristics which have never been done by other one. The aim of this study is to measure the electron density profile of an arc plasma by Mach-Zenhder interferometer. The two laser beams (He-Ne and Argon Lasers), which are different in wavelength, pass across an arc plasma and meet a change of refractivity which makes fringe shifts. From this effects we could find densities of electron and neutral particle.