• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.515-515
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• 2012

일반적으로 저온 대기압 플라즈마는 표면개질이나 의료도구, 식수등 살균장치에 많이 이용되고 있으며 현재에는 혈액응고, 치아 치료등의 바이오분야에도 활발한 연구가 진행되어지고 있다. 그러나 저온 대기압 플라즈마는 가스 유량, 전극간격, 물질, 모양에 따라 인가되어지는 전자기장이 특성이 상이하다. 본 연구에서는 시뮬레이션을 이용하여 저온 대기압 플라즈마 젯(jet) 소스에서 전극의 간격에 따른 전자기장의 세기를 계산하였고, 전극의 거리별 저온 대기압 플라즈마 젯(jet) 소스에서 인가되는 전압과 비교를 해보았다. 그 결과 시뮬레이션 값과 실험결과가 유사한 경향을 보이는 것을 본 연구에서 확인할 수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.3
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• pp.451-461
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• 2001

We present a simple design method of velocity-matched traveling-wave (TW) electrode with periodic capacitive loads. Once matching impedance and optical phase velocity are defined, the width and separation of coplanarstrip (CPS) and the magnitude and period of capacitive load are determined analytically. Calculation results of velocity-matched TW electrodes on GaAs substrates show bandwidths of more than 100 GHz.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.183-195
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• 2014

In order to study the mineralogical characteristics of a cathodic deposition-metallic powder, electrowinning experiments were carrier out on different electrolytic solutions at varying electric distances and electric currents. Under the same experimental conditions, Cu recovery was obtained much more effectively using a sodium chloride electrolyte than with a sulfuric acid electrolyte. In XRD analysis, copper ($Cu^0$), chalcanthite and cuprite were identified in the sulfuric acid electrolyte, while copper, nantokite and chalcanthite were observed in the sodium chloride electrolyte. In the sodium chloride electrolyte solution, increasing the electric distance and the electric current increased the Cu recovery rate, anode weight and anodic corrosion. The results of XRD analysis with non-pulverized cathodic deposition-metallic powder showed the average copper crystallite size was increased by increasing the electric current and decreasing the electric distance. It is suggested that the mass transfer was controlled with diffusion on the boundary between the electrode and the electrolytic solution due to the formation of dendrite copper.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.6
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• pp.492-498
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• 2012

Characteristics of DBD(Dielectric Barrier Discharge) plasma actuator as design parameters were investigated for plasma flow control. Flow velocity and power consumption of the DBD plasma actuator were measured according to the design parameters such as discharge voltage and frequency, gap, width and length of electrode, and the thickness of dielectric barrier. The flow velocity and power consumption increased as the discharge voltage and frequency increased. As the electrode gap increased, the flow velocity increased with decreasing the power consumption, whereas high voltage was required for the plasma discharge. The flow velocity increased as the upper-electrode width decreased, and as the lower-electrode width increased at the constant power consumption. The performance of the DBD plasma actuator can be estimated at the given discharge and geometry conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.238-238
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• 1999

현대 AC-PDP(Plasma Display Panel)의 유지전극 구조는 공면 전극구조를 가지고 있다. 공면 전극구조하에서 Ne-Xe 혼합가스에 대한 이온화율 측정을 시도하였다. 일정한 전극 간격을 가지고 있는 공면 전극 구조에서 암전류와 방전류를 측정함으로써 이온화율을 측정하였다. 본 실험의 결과를 통하여 압력으로 규격화된 전기장에 대하여 압력으로 규격화된 이온화율을 나타낼 수 있으며 단일 가스에 대한 이온화율과 혼합값에 대한 이온화율을 비교할 수 있으며 실제 PDP구조하에서의 이온화율을 적용할 수 있다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.124-129
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• 2010

When a phenolic resin is carbonized by the leakage current flowing along its surface, the carbonization pattern is one of the most important factors to determine its carbonization characteristics. However, the typical carbonization pattern of a phenolic resin is too complicated to be analyzed by conventional Euclidean geometry. In most cases, such a complicated shape shows a fractal structure. It is possible, therefore, to examine the characteristics of the carbonization pattern regarding a given phenolic resin. In order to quantitatively investigate the carbonization pattern of the phenolic resin carbonized by a leakage current, in this paper, the fractal dimension of the carbonization pattern has been calculated as a function of the magnitude of a leakage current and the distance between two electrodes. For reliability of calculation, the correlation function as well as the box counting method has been used to calculate the fractal dimension. According to the result of calculation, the fractal dimension increases as the current increases at the constant electrode gap distance. However, there is no significant relation between the fractal dimension and the electrode gap distance at a constant current.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.503-503
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• 2012

본 연구에서는 최대전압 600 KV, 최대전류 88 KA, 펄스 폭 60 ns의 특성을 가지는 고전압 펄스 시스템 '천둥'을 이용하여 방전 챔버에 고전압 펄스를 인가하고 $N_2$와 $SF_6$ 혼합기체 종류와 여러 가지 기체압력에서 전기 트리거를 이용한 방전현상을 전기, 광학적으로 연구하였다. 전극은 구리텅스텐 합금재질의 표준전극을 사용하였고, 전극 간격은 10 mm로 고정하였다. 방전 챔버 압력을 100 torr, 1기압, 2 기압에서 실험을 진행하였고, $N_2$에 대한 $SF_6$의 혼합비율을 0~100%까지 변화시키며 실험을 진행하였다. 전기 트리거 신호가 인가된 펄스 방전 스위치의 방전전압 및 방전 기작원리, 트리거 스위칭 지연시간, 트리거 절연파괴 기작원리, 그리고 이때 생성된 플라스마의 전자 온도 및 밀도에 관한 전기광학 특성 등에 관한 기초연구를 수행하였다. 트리거 펄스가 있을 때의 방전개시전압은 트리거 지연시간 20 us 에서 최소가 되는 특성을 보이며, 이때의 SF6 함량에 따른 최소방전전압과 트리거 펄스가 없을 때의 방전전압을 서로 비교하였다. 이를 통하여 A-K gap 10 mm 조건에서 20 us의 트리거 펄스의 지연시간을 가지는 방전 개시전압은 트리거 펄스가 없을 때 전극 간격이 6 mm에 해당되는 방전개시 전압 값을 가짐을 실험적으로 보였다. 이는 트리거 펄스에 의하여 전극 주위에 쉬스가 형성되며, 이로 인한 전극 간격이 가까워지며, 이와 같은 효과 때문에 방전개시전압은 그만큼 낮아지는 것으로 해석 할 수 있다.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.6
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• pp.67-76
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• 2005

This paper proposes a compact-sized surface myoelectric sensor for the myoelectric hand prosthesis. To fit the surface myoelectric sensor in the socket for the myoelectric hand prosthesis, the sensor should be a compact size. The surface myoelectric sensor is. composed of a skin interface and a single processing circuit that are mounted on a single package. The skin interface has one reference and two input electrodes, and the reference electrode is located in the center of two input electrodes. In this paper we propose two types of sensors with the circle- and bar-shaped reference electrode, but all input electrodes are the bar-shaped. The metal material of the electrodes is the stainless steel (SUS440) that endures sweat and wet conditions. Considering the conduction velocity and the median frequency of the myoelectric signal, we select the inter-electrode distance (IED) between two input electrodes as 18mm, 20mm, and 22 mm. The signal processing circuit consists of a differential amplifier with a band pass filter, a band rejection filter for rejecting 60Hz power-line noise, amplifiers, and a mean absolute value circuit. We evaluate the proposed sensor from the output characteristics according to the IED and the shape of the reference electrode. From the experimental results we show the surface myoelectric sensor with the 18mm IED and the bar-shaped reference electrode is suitable for the myoelectric hand prosthesis.

• Journal of Sensor Science and Technology
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• v.7 no.2
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• pp.90-96
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• 1998

Non-contacting capacitive sensors, based on principle of the cross capacitor, for measuring small displacement less than $1.95{\pm}0.5\;mm$ have been fabricated and characterized. To overcome disadvantages of the existed capacitive sensors with 2-electrodes and 3-electrodes, the new sensor is consisted of 4-electrodes which are formed two electrode(high, low) and 2 guard electrodes on a sapphire plate with diameter 17 mm and thickness 0.7 mm, and are symmetrically situated with a constant gap of 0.2 mm between the electrodes. This sensor can be used for measuring both metallic and non-metallic target without ground connection, and is evaluated to the correlation coefficient of 0.9987 for the range of $1.95{\pm}0.5\;mm$ and that of 0.9995 for $1.95{\pm}0.25\;mm$ range.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2007.05a
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• pp.346-350
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• 2007

Pt/TI, Ir/Ti, Ru/Ti의 세가지 종류의 전극을 이용하여 전기분해공정에서 레지오넬라균의소독효과를 고찰한 결과 기존 산업계에서 가장 많이 사용하는 Pt/Ti 전극의 성능이 떨어지는 것으로 나타났고, Ru/Ti 전극의 성능이 가장 우수한 것으로 나타났다. NaCl 농도가 높을수록 전기전도도가 높아지기 때문에 소요되는 전력도 감소하고 소독효과도 증가하지만 염소에 대한 냉각수의 수질기준을 고려할 때 최적 NaCl 첨가량은 0.0125%로 사료되었다. 전극 간격이 넓을수록 소독효과가 감소하는 것으로 나타났다.