• 한국결정성장학회지
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• 제20권2호
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• pp.101-105
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• 2010

플라즈마 에쳐 내에 사용되는 실리콘 전극과 링 부품은 사용 중에 강한 플라즈마와 접촉하면서 주기적인 가열과 냉각 과정을 거친다. 이 때 부품의 표면에서는 열 응력으로 인하여 PSB라고 하는 띠 형상의 결함이 생성되며 이로 인하여 그 수명을 다하게 된다. 원료인 실리콘 잉곳의 관점에서 그 수명에 미치는 인자를 살펴보았다. 잉곳의 등급, 즉 S/F와 S/A에 따라 불순물과 결함의 농도를 GDMS와 ${\mu}$-PCD로 평가하여 잉곳의 어떤 요소들에 의하여 수명이 결정되는가를 분석하였다. 그 결과, {001} 면상에서 관찰되는 <110> 방향의 면 결함들이 PSB와 연결될 가능성이 있음을 제안하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.241.1-241.1
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• 2014

The large-area high-power radio-frequency (RF) driven ion sources based on the negative hydrogen (deuterium) ion beam extraction are the major components of neutral beam injection (NBI) systems in future large-scale fusion devices such as an ITER and DEMO. Positive hydrogen (deuterium) RF ion sources were the major components of the second NBI system on ASDEX-U tokamak. A test large-area high-power RF ion source (LAHP-RaFIS) has been developed for steady-state operation at the Korea Atomic Energy Research Institute (KAERI) to extract the positive ions, which can be used for the NBI heating and current drive systems in the present fusion devices, and to extract the negative ions for negative ion-based plasma heating and for future fusion devices such as a Fusion Neutron Source and Korea-DEMO. The test RF ion source consists of a driver region, including a helical antenna and a discharge chamber, and an expansion region. RF power can be transferred at up to 10 kW with a fixed frequency of 2 MHz through an optimized RF matching system. An actively water-cooled Faraday shield is located inside the driver region of the ion source for the stable and steady-state operations of RF discharge. The characteristics and uniformities of the plasma parameter in the RF ion source were measured at the lowest area of the expansion bucket using two RF-compensated electrostatic probes along the direction of the short- and long-dimensions of the expansion region. The plasma parameters in the expansion region were characterized by the variation of loaded RF power (voltage) and filling gas pressure.

• 한국가금학회지
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• 제17권2호
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• pp.83-91
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• 1990

닭의 Cholecystokinin (CCK) 방출에 미치는 사료성분에 대한 효과에 대해서 stomach tube에 의한 사료투여에 의해, 특수 CCK-8 antibody 를 이용해서 그 혈중 CCK의 농도를 측정했다. 실험 1에서, 무단백질사료에 대두단백질 및 대두단백질과 같은 조성의 아미노산혼합물을 첨가해서 투여한 결과 무단백질사료에 비교해서 유의하게 높은 증가를 보였으며, 아미노산혼합물사료투여가 단백질사료투여보다 빠른 증가가 관찰되었다. 무단백질사료에 아미노산을 단독으로 첨가하여 투여한 결과. phenylalanine 첨가 사료에서 Plasma중의 CCK농도가 가장 높게 나타나 아미노산혼합물과 같은 수준으로 나타났으며. 뒤이어 arginine이, valine에서 가장 낮은 분필반응이 관찰되었다. 실험 2와 3에서, 단백질사료에 SBTI를 첨가하여 투여한 결과, SBTI첨가 사료에 의해 Plasma CCK 농도는 투여 후 급격히 증가하였으며, 그 반응은 1,000mg첨가가 100mg/kg첨가보다 높은 dose response가 관찰되었다. SBTI첨가 사료에 의한 crop emptying에는 처리군과 차이가 나타나지 않아, SBTI가 단독으로 plasma CCK농도를 상승시킨다고 생각된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.228.2-228.2
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• 2016

The triggered vacuum switch (TVS) discharges high current through two processes. In the first process, an igniting plasma is generated at a trigger system, and the next process that a main discharge is taken place sequentially at a six-gap rod electrode within a few microsecond. In general, a triggered voltage producing the igniting plasma is increased. However, after several hundred shots, it goes down and stable, in our experiment the trigger voltage is about 5 kV after 250 shots. This triggered characteristics comes from the ceramic insulator which is covered by an electrode material, therefore we have focused on the first igniting plasma process. The igniting plasma has been generated at the surface of a ceramic insulator under a strong electric field. The electric field can be increased through modifying geometries of trigger components which compose of a trigger pin, a ceramic insulator and an enclosed holder. We fabricated not only two types of trigger pin which are a plane head and an umbrella head type, but two different holders which are a concave and a convex type. In this paper the result that the dependency of geometries for these four combined types is included, but the study of the ceramic insulator is not. The research of the ceramic insulator will be announced in the other paper.

• 전자공학회논문지
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• 제50권10호
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• pp.124-131
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• 2013

플라즈마(Plasma) 공정 시뮬레이션에서 가장 중요한 요소는 식각(Etching) 과정으로 특성 정보 프로파일(Feature Profile)에 의존하는 식각 비율(Etch Rate)을 계산하는 것이다. 식각 비율을 결정 요소는 이온 플럭스(Ion Flux), 뉴트럴 플럭스(Neutral Flux), 가스 종 온도 등 다양하지만 본 논문에서는 이온 플럭스(Ion Flux)에 한정하여 고속으로 이온 플럭스를 계산하기 위한 스캔 방법을 제안했다. 그리고 일반적으로 많이 사용되어지는 몬테카를로(Monte Carlo) 방법과 제안 방법을 가우시안 분포 및 코사인 분포를 이용하여 실험하고 서로 비교 분석하였다. 본 논문에서 제안한 방법이 몬테카를로 방법과 비교 했을 때 보다 효율적으로 정확한 이온 플럭스를 계산 할 수 있음을 검증하였다.

• Korean Chemical Engineering Research
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• 제60권3호
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• pp.452-458
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• 2022

3가지 종류의 기-액 하이브리드 수평형, 수직형 그리고 needle-to-cylinder형 플라즈마 반응기가 제작되었다. 이들 반응기를 통하여 대기압 플라즈마 방전에서 발생하는 반응 활성종 생성과 전극 내의 전위차를 통한 세정성분의 기-액 활성화 반응을 일으키는 고효율 친환경 기반의 세정 개념을 제시하였다. 세정성능에 대한 효율성을 비교한 결과, needle-to-cylinder형 반응기가 가장 우수한 특성을 가졌다. 본 연구를 통해 기-액 하이브리드 대기압 플라즈마 반응기가 반도체 공정 등 초정밀 세정공정에 응용 가능성이 있음을 확인하였다.

• Journal of Veterinary Science
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• 제24권2호
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• pp.33.1-33.7
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• 2023

Background: Laminitis is a complex and debilitating disease of horses. Numerous predisposing factors contribute to laminitis development, however the exact pathogenesis remains undetermined. Serum T4, cortisol, and histamine are components of the innate stress response and could play a causative or contributory role. Stress hormone concentrations in laminitis are largely unknown. Objective: To evaluate parameters associated with stress response in horses with laminitis, and compare these to healthy horses and horses with gastrointestinal (GI) disease. Methods: Thirty-eight adult horses presenting for non-medical conditions, GI abnormalities, or clinical laminitis were prospectively enrolled. Horses were assigned to the appropriate disease group (healthy, GI disease, and laminitis) and had blood drawn on presentation to the hospital. Samples were analyzed for plasma endogenous adrenocorticotrophic hormone (eACTH), serum cortisol, serum thyroid hormone, and plasma histamine. Results: Stress hormone concentrations were significantly different between horses in the laminitis and GI disease groups. Plasma histamine levels were highest in horses with laminitis, compared with GI disease and controls. Both horses with laminitis and GI disease had increased plasma eACTH when compared to healthy horses. Horses with GI disease had higher serum cortisol concentrations than horses with laminitis or controls. Serum T4 was lower in horses with GI disease than in horses with laminitis and controls. Conclusions: Horses with laminitis had relative increases in both plasma histamine and eACTH concentrations. Serum T4 and cortisol concentrations of horses with laminitis did not differ significantly when compared to healthy horses. The role of stress hormones in equine disease warrants further investigation.

• 한국재료학회지
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• 제33권7호
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• pp.309-314
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• 2023

This study aimed to address the limitations of traditional plasma nitriding methods by implementing a short-term plasma oxy-nitriding treatment on the surface of AISI 420 martensitic stainless steel. This treatment involved the sequential formation of nitride and oxide layers, to enhance surface hardness and corrosion resistance, respectively. The process resulted in the formation of a 20 ㎛-thick nitride layer and a 3 ㎛-thick oxide layer on the steel surface. Initially, the hardness increased by 2.2 times after nitriding, followed by a subsequent decrease of approximately 31 % after oxidation. While the nitriding process reduced corrosion resistance, the subsequent oxidation process led to the formation of a passive oxide film, effectively resolving this issue. The pitting corrosion of the oxide passive film started at 82.6 mVssc, providing better corrosion resistance characteristics than the nitride layer. Consequently, the trade-off between surface hardness and corrosion resistance in plasma oxy-nitrided AISI 420 martensitic stainless steel is anticipated to be recognized as an innovative and comprehensive surface treatment process for biomedical components.

• 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.

• 대한수의학회지
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• 제36권3호
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• pp.743-745
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• 1996

가축 특히 대동물에 있어서 전방수의 화학조성에 관한 보고는 극히 드물다. 따라서 본 연구에서는 한우 및 유우(Holstein)를 대상으로 전방수에 대해 화학조성을 검토하였다. 유의의 protein, urea nitrogen, creatinine, cholesterol, calcium, sodium, potassium과 chloride 등이 분석 검출되었다. 이러한 조성분포는 혈장에서 보다는 수액(cerebrospinal fluid)의 조성에 더 유사한 것으로 나타났으며, 한우 및 유우에 있어서 조성에 관한 차이는 거의 인정되지 않았다.