• 한국전기전자재료학회논문지
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• 제15권11호
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• pp.969-975
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• 2002

Thin film transistors(TFT) were made based on the polycrystalline Si (poly-Si) crystallized by sequential lateral solidification(SLS) method. The electrical characteristics of the devices were analyzed. n-type TFTs did not show a superior characteristics compared to p-type TFTs. We analyzed the causes of the failure by focused ion beam(FIB) analysis and automatic spreading resistance(ASR) measurement, to study the structural integrity and the doping distribution, respectively. FIB showed no structural problems but it revealed a non-intermixed layer in the contact holes between the polysilicon and the aluminum electrode. ASR analyses on poly-Si layer with various doping concentrations and activation temperatures showed that the inadequately doped areas were partially responsible for the inferior behavior of the whole device.

• 한국결정성장학회지
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• 제13권2호
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• pp.93-97
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• 2003

FALC(Field-Aided Lateral Crystallization) 공정에서 요구되는 a-Si의 결정화는 인가한 전계(electric field)의 세기와 방향에 의존한다. 본 연구에서는 유한요소법을 적용하여 실제 패턴을 간단하게 모델링한 형상에 각 물질의 전도도를 대입하고, 전안을 가해 그 결과로 발생하는 전계의 분포를 계산하였다. 전계는 (-)극 주위에서 전극의 양쪽 모서리 부근이 가운데 부분보다 더 높게 나타났고 그 방향은 전극과 50~$60^{\circ}$를 이루는 대각선 방향이었다. 또한 예상한대로 크기가 작은 패턴이 큰 패턴보다 더 큰 전계 값을 가지는 것으로 나타났다.

• 전기화학회지
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• 제16권4호
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• pp.211-216
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• 2013

At Pt(111), Pt(100), Pt, and Rh interfaces, the Frumkin adsorption isotherm of underpotentially deposited hydrogen (UPD H) and related electrode kinetic data are determined using the standard Gibbs energy of adsorption. The Temkin adsorption isotherm of UPD H correlating with the Frumkin adsorption isotherm of UPD H is readily determined using the correlation constants between the Temkin and Frumkin or Langmuir adsorption isotherms. At the Pt(111), Pt(100), Pt, and Rh interfaces, the lateral repulsive interaction between the UPD H species is interpreted using the interaction parameter for the Frumkin adsorption isotherm. The lateral repulsive interaction between the UPD H species at the Pt(111), Pt(100), Pt, and Rh interfaces is significantly different from the lateral attractive interaction between the overpotentially deposited hydrogen (OPD H) species at Pt, Ir, and Pt-Ir alloy interfaces.

• 한국결정성장학회지
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• 제12권4호
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• pp.210-214
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• 2002

$450^{\circ}C$ 이하에서 Cu를 이용한 전계 유도 방향성 결정화 공정을 통해 비정질 실리콘의 결정화 거동을 고찰하였다. 열처리와 동시에 전계를 인가하여 Cu가 증착된 패턴의 외부에서 Cu가 존재하지 않는 비정질 실리콘의 영역으로 측면 결정화를 유도하였다. 특히, Cu가 존재하지 않는 영역의 측면결정화는 (-) 전극 쪽에서 (+) 전극 쪽으로 방향성을 가지고 결정화가 진행되었다. 이러한 현상은 Cu와 Si가 반응 할 때, 주확산 종이 금속(Cu)이기 때문에 가능하다고 판단되었다. 또한, FALC 공정을 이용한 $350^{\circ}C$의 온도에서 결정화된 영역 내에 커다란 dendrites 형태의 가지가 형성되었고 전계 방향에 따른 측면 결정화가 진행되었음을 확인하였다. 결론적으로 $350^{\circ}C$의 매우 낮은 온도에서 30 V/cm의 전계 인가를 통해 12$\mu$m/h의 결정화 속도로 결정화가 가능함을 확인하였다.

• Journal of Korean Neurosurgical Society
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• 제56권1호
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• pp.71-74
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• 2014

Cancer-related facial pain refractory to pharmacologic management or nondestructive means is a major indication for destructive pain surgery. Stereotactic mesencephalotomy can be a valuable procedure in the management of cancer pain involving the upper extremities or the face, with the assistance of magnetic resonance imaging (MRI) and electrophysiologic mapping. A 72-year-old man presented with a 3-year history of intractable left-sided facial pain. When pharmacologic and nondestructive measures failed to provide pain alleviation, he was reexamined and diagnosed with inoperable hard palate cancer with intracranial extension. During the concurrent chemoradiation treatment, his cancer-related facial pain was aggravated and became medically intractable. After careful consideration, MRI-based stereotactic mesencephalotomy was performed at a point 5 mm behind the posterior commissure, 6 mm lateral to and 5 mm below the intercommissural plane using a 2-mm electrode, with the temperature of the electrode raised to $80^{\circ}C$ for 60 seconds. Up until now, the pain has been relatively well-controlled by intermittent intraventricular morphine injection and oral opioids, with the pain level remaining at visual analogue scale 4 or 5. Stereotactic mesencephalotomy with the use of high-resolution MRI and electrophysiologic localization is a valuable procedure in patients with cancer-related facial pain.

• 한국강구조학회 논문집
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• 제26권5호
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• pp.407-418
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• 2014

본 연구에서는 HSA800 후판 강재에 적합한 용접재를 선정하고자 휨-인장실험을 수행하였다. 본 연구 수행 당시 HSA800 강재에 적용가능한 용접재로 GMAW 용접재(외국산)와 FCAW 용접재(국내산) 두 가지가 추천되어 이들을 사용하였다. 선행연구인 표준인장실험 결과를 바탕으로 맞댐용접상세와 루트간격을 주요 실험변수로하여 실물크기의 보 실험을 통해 용접부의 성능을 평가하였다. 강도 측면에서 모멘트 및 플랜지 축력 전달에 대한 조건은 두 용접재 모두 만족하였으나 연성능력 측면에서 GMAW 용접재보다는 FCAW 용접재가 일관되고 우수한 거동을 보임이 실험적으로 확인되었다. 특히 GMAW 용접재는 용접효율과 작업성의 문제로 현장에서의 상향용접이 어려운 것으로 파악되었다. 같은 완전용입용접이라도 Single bevel보다는 V-groove가 안정적인 구조거동을 보이는 것으로 나타났다. 표준인장실험결과와 휨-인장실험결과를 토대로 HSA800 후판재의 용접상세 및 용접재를 제시하였다.

• 신재생에너지
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• 제4권2호
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• pp.74-80
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.

• Journal of Electrochemical Science and Technology
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• 제8권4호
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• pp.331-337
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• 2017

A simple strategy is proposed herein for attaining uniform current distribution in direct methanol fuel cells by varying the catalyst loading over the electrode. In order to use the same total catalyst amount for a serpentine flow field, three spatial variation types of catalyst loading were selected: enhancing the cathode catalyst loading (i) near the cathode outlet, (ii) near the cathode inlet, and (iii) near the lateral areas. These variations in catalyst loading are shown to improve the homogeneity of the current distribution, particularly at lower currents and lower air-flow rates. Among these three variations, increased loading near the lateral areas was shown to contribute most to achieving a homogenous current distribution. The mechanism underlying each catalyst loading variation method is different; very high catalyst-loading is shown to decrease the homogeneity of the distribution, which may be caused by water management in the thick catalyst layer thereof.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.390-393
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• 2008

To improve the blue responses of screen-printed single crystalline silicon solar cells, we investigated an emitter etch-back technique to obtain high emitter sheet resistances, where the defective dead layer on the emitter surface was etched and became thinner as the etch-back time increased, resulting in the monotonous increase of short circuit current and open circuit voltage. We found that an optimal etch-back time should be determined to achieve the maximal performance enhancement because of fill factor decrease due to a series resistance increment mainly affected by contact and lateral resistance in this case. To elucidate the reason for the fill factor decrease, we studied the resistance analysis by potential mapping to determine the contact and the lateral series resistance. As a result, we found that the fill factor decrease was attributed to the relatively fast increase of contact resistance due to the dead layer thinning down with the lowest contact resistivity when the emitter was contacted with screen-printed silver electrode.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.647-650
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• 2002

A lateral type GaN field emission diodes were fabricated by utilizing metal organic chemical vapor deposition (MOCVD). In forming the pattern, two kinds of procedures were proposed: a selective etching method with electron cyclotron resonance-reactive ion etching (ECR-RIE) or a simple selective growth by utilizing $Si_3N_4$ film as masking layer. The fabricated device using the ECR-RIE exhibited electrical characteristics such as a turn-on voltage of 35 V for 7 ${\mu}m$ gap and an emission current of ${\sim}580$ nA/10tips at anode-to-cathode voltage of 100 V These new field emission characteristics of GaN tips are believed to be due to a low electron affinity as well as the shorter inter-electrode distance.