• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.269-269
• /
• 2012

A new ion source has been designed, fabricated, and installed at the NBTS (Neutral Beam Test Stand) at the KAERI (Korea Atomic Energy Research Institute) site. The goalis to provide a 100 keV, 2MW deuterium neutral beam injection as an auxiliary heating of KSTAR (Korea Super Tokamak Advanced Research). To cope with power demand, an ion current of 50 A is required considering the beam power loss and neutralization efficiency. The new ion source consists of a magnetic cusp bucket plasma generator and a set of tetrode accelerators with circular copper apertures. The plasma generator for the new ion source has the same design concept as the modified JAEA multi-cusp plasma generator for the KSTAR prototype ion source. The dimensions of the plasma generator are a cross section of $59{\times}25cm^2$ with a 32.5 cm depth. The anode has azimuthal arrays of Nd-Fe permanent magnets (3.4 kG at surface) in the bucket and an electron dump, which makes 9 cusp lines including the electron dump. The discharge properties were investigated preliminarily to enhance the efficiency of the beam extraction. The discharge of the new ion source was mainly controlled by a constant power mode of operation. The discharge of the plasma generator was initiated by the support of primary electrons emitted from the cathode, consisting of 12 tungsten filaments with a hair-pin type (diameter = 2.0 mm). The arc discharge of the new ion source was achieved easily up to an arc power of 80 kW (80 V/1000 A) with hydrogen gas. The 80 kW capacity seems sufficient for the arc power supply to attain the goal of arc efficiency (beam extracted current/discharge input power = 0.8 A/kW). The accelerator of the new ion source consists of four grids: plasma grid (G1), gradient grid (G2), suppressor grid (G3), and ground grid (G4). Each grid has 280 EA circular apertures. The performance tests of the new ion source accelerator were also finished including accelerator conditioning. A hydrogen ion beam was successfully extracted up to 100 keV /60 A. The optimum perveance is defined where the beam divergence is at a minimum was also investigated experimentally. The optimum hydrogen beam perveance is over $2.3{\mu}P$ at 60 keV, and the beam divergence angle is below $1.0^{\circ}$. Thus, the new ion source is expected to be capable of extracting more than a 5 MW deuterium ion beam power at 100 keV. This ion source can deliver ~2 MW of neutral beam power to KSTAR tokamak plasma for the 2012 campaign.

• 한국세라믹학회지
• /
• 제41권6호
• /
• pp.456-463
• /
• 2004

음극지지형 SOFC의 성능을 향상시키기 위해 단전지 제조공정을 개선하고 그 출력특성을 평가하였다. 액상응결 공정(Liquid Condensation Process : LCP)과 일축가압성형공정을 통하여 NiO/YSZ 복합체 음극기판을 제조하고 위에 YSZ 전해질을 스크린 인쇄한 후 140$0^{\circ}C$에서 3시간동안 동시소결하여 음극/전해질 기판을 제조하였다. 또한 LSM/YSZ 양극층은 임피던스 분석을 통해 분극저항이 최소가 되는 조성 및 열처리 조건을 선택하여 스크린 인쇄법을 이용해 구성하였고 이러한 적층공정을 거쳐 최종적으로 5${\times}$5와 l0${\times}$10 $\textrm{cm}^2$ 크기의 단전지를 제조하였다. 제조된 단전지의 출력특성을 측정한 결과 5${\times}$5와 10${\times}$10 단전지는 80$0^{\circ}C$에서 약 0.45W/$\textrm{cm}^2$ 와 0.22 W/$\textrm{cm}^2$의 최대출력밀도를 각각 나타내어 선행연구에서 기존공정으로 제조된 단전지에 비해 2배 이상 향상된 좋은 성능을 나타내었다.

• 한국표면공학회:학술대회논문집
• /
• 한국표면공학회 1999년도 추계학술발표회 초록집
• /
• pp.15-15
• /
• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제40회 동계학술대회 초록집
• /
• pp.204-205
• /
• 2011

In thin film silicon solar cells, p-i-n structure is adopted instead of p/n junction structure as in wafer-based Si solar cells. PECVD is a most widely used thin film deposition process for a-Si:H or ${\mu}c$-Si:H solar cells. For best performance of thin film silicon solar cell, the dopant profiles at p/i and i/n interfaces need to be as sharp as possible. The sharpness of dopant profiles can easily achieved when using multi-chamber PECVD equipment, in which each layer is deposited in separate chamber. However, in a single-chamber PECVD system, doped and intrinsic layers are deposited in one plasma chamber, which inevitably impedes sharp dopant profiles at the interfaces due to the contamination from previous deposition process. The cross-contamination between layers is a serious drawback of a single-chamber PECVD system in spite of the advantage of lower initial investment cost for the equipment. In order to resolve the cross-contamination problem in single-chamber PECVD systems, flushing method of the chamber with NH3 gas or water vapor after doped layer deposition process has been used. In this study, a new plasma process to solve the cross-contamination problem in a single-chamber PECVD system was suggested. A single-chamber VHF-PECVD system was used for superstrate type p-i-n a-Si:H solar cell manufacturing on Asahi-type U FTO glass. A 80 MHz and 20 watts of pulsed RF power was applied to the parallel plate RF cathode at the frequency of 10 kHz and 80% duty ratio. A mixture gas of Ar, H2 and SiH4 was used for i-layer deposition and the deposition pressure was 0.4 Torr. For p and n layer deposition, B2H6 and PH3 was used as doping gas, respectively. The deposition temperature was $250^{\circ}C$ and the total p-i-n layer thickness was about $3500{\AA}$. In order to remove the deposited B inside of the vacuum chamber during p-layer deposition, a high pulsed RF power of about 80 W was applied right after p-layer deposition without SiH4 gas, which is followed by i-layer and n-layer deposition. Finally, Ag was deposited as top electrode. The best initial solar cell efficiency of 9.5 % for test cell area of 0.2 $cm^2$ could be achieved by applying the in-situ plasma cleaning method. The dependence on RF power and treatment time was investigated along with the SIMS analysis of the p-i interface for boron profiles.

• Korean Chemical Engineering Research
• /
• 제50권3호
• /
• pp.562-566
• /
• 2012

본 논문에서는 세그먼트 관형 고체산화물 연료전지(SOFC)의 설계 및 제작과 특성 분석을 다루고 있다. 관형 세라믹 지지체는 압출 공정을 통하여 제작하였으며, NiO-YSZ 연료극과 YSZ 전해질은 담금 코팅법을 통해 세라믹 지지체에 코팅하였다. 코팅된 세라믹 지지체를 $1,350^{\circ}C$에서 5시간 동안 열처리하였으며, $10{\mu}m$ 미만의 치밀하고, 균열이 없는 YSZ 전해질 층을 얻을 수 있었다. 또한 열처리된 세라믹 지지체에 LSM-YSZ/LSM/LSCF로 구성된 다층 구조 공기극을 담금법으로 코팅하여 $1,150^{\circ}C$에서 열처리하였다. 세라믹 관형 지지체에 코팅된 세그먼트 SOFC 셀은 Ag-glass 연결재를 사용하여 전기적으로 직렬 연결하였으며, 수소연료 유량과 운전 온도에 따른 세그먼트 SOFC의 성능 변화를 측정하였다.

• 대한임상검사과학회지
• /
• 제50권4호
• /
• pp.470-476
• /
• 2018

다중펄스경두개전기자극(mpTES)을 이용한 안면운동유발전위(FMEP)는 자유 진행 근전도와 직접적인 안면 신경 자극법의 한계점을 보완하고 소뇌교각 종양 수술 중에 안면 신경의 기능적인 완전성을 예측할 수 있다. 본 논문의 목적은 이 검사의 표준화된 검사방법과 안면 신경의 기능예측인자로서의 유용성을 알아보고 수술 후 중대한 후유증인 안면마비 발생률을 최소화하는 것이다. Mz (음극)-M3, M4 (양극) 전극으로 경두개전기자극을 주고 안면운동유발전위의 단일펄스반응(SPR)의 부재와 10 ms이상의 잠복기를 확인해서 직접적인 두개 외 말초 안면 근육 자극을 배제하고 구륜근(orbicularis oris)과 턱근(mentalis)에서 동시에 측정하면 구륜근에서만 측정했을 때보다 안면운동유발전위의 정확도와 성공률을 높일 수 있다. 본 논문에서는 안면운동유발전위의 50% 진폭감소를 경고기준으로 해서 수술 직후 안면 신경의 결과를 효과적으로 예측할 수 있었다. 결론적으로, 소뇌교각 종양 수술 중에 FMEP는 자유 진행 근전도와 직접적인 안면 신경 자극법과 더불어서 수술 후 중대한 후유증인 안면 마비 발생률을 최소화 할 수 있는 유용한 검사방법이다.