• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2002년도 추계학술대회 논문집
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• pp.89-93
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• 2002

Resistance performance of 6.67 G/T class fishing vessel is experimentally investigated in low and middle speed ranges to find out the effect of a new chine. The tests are performed for four different cases in the circulating water channel(CWC). Wave patterns are observed together to make clear the relation between the resistance performance and the wave characteristics. The results show that the new chine can be one of the effective device to reduce the resistance.

• 한국산학기술학회논문지
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• 제5권1호
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• pp.13-15
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• 2004

고속처리를 위한 나노급의 논리소자의 개발을 위해서는 소스/드레인 영역의 저항을 감소시키는 것이 필수적이다. 반도체소자의 개발 로드맵을 제시하고 있는 ITRS의 보고에 의하면 70㎚급 MOSFET에서는 채널영역의 저항에 대비하여 그 외의 영역이 나타내는 저항성분이 약 15% 이내로 제작되어야 할 것으로 예측하고 있다. 이 기준을 유지하기 위해서는 소스/드레인 영역의 각 전류 흐름에 기인하는 가상적 기생저항에 대한 성분 분리와 이들이 가지는 저항값에 대한 정량적 계산이 이루어져야 한다. 이에 본 논문은 calibration된 TCAD simulation을 통해 나노영역의 Tr.에서 저항성분을 계산, 평가하는 방법을 연구하였다. 특히, 소스/드레인 영역의 실리사이드 접촉 저항성분들을 최소화하여 optimize하기 위한 전략을 제시한다.

• 대한기계학회논문집B
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• 제32권9호
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• pp.683-694
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• 2008

The performance and durability of Polymer Electrolyte Fuel Cells (PEFCs) are strongly influenced by the uniformity of current density, temperature, species distributions inside a cell In order to obtain uniform distributions in them, the optimal design of flowfield must be a key factor. In this paper, the numerical study of land/channel flowfield optimizations is performed, using a multi-dimensional, multi-phase, non-isothermal PEFC model. Numerical simulations reveal more uniform current density and HFR(High Frequency Resistance) distributions and thus better PEFC performance with narrower land/channel width where the less severe oxygen depletion effect near the land region and more uniform contact resistance variation along the in-plane direction are achieved. The present study elucidates detailed effects of land/channel width and assist in identifying optimal flow-field design strategies for the operation of PEFCs.

• 융합정보논문지
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• 제11권11호
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• pp.159-165
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• 2021

본 삼차원 선택적 산화를 이용하여 20 nm 수준의 핀 폭과 점진적으로 증가된 소스/드레인 확장 영역을 갖는 핀 채널을 벌크 실리콘 기판에 제작하였다. 제안된 기법을 이용하여 삼차원 소자를 제작하기 위한 공정기법 및 단계를 상세히 설명하였다. 삼차원 소자 시뮬레이션을 통해, 제안된 소자의 주요 특징과 특성을 기존 FinFET 및 벌크 FinFET 소자와 비교하였다. 제안된 삼차원 선택적 산화 방식의 핀 채널 MOSFET는 기존의 소자들과 비교하여 더 큰 구동 전류, 더 높은 선형 트랜스컨덕턴스, 더 낮은 직렬 저항을 가지며, 거의 유사한 수준의 소형화 특성을 보이는 것을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제33권5호
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• pp.550-556
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• 2022

In this study, the flow uniformity was analyzed by performing numerical analysis on the 1 kWe internal manifold type solid oxide fuel cell stack according to the channel height of the separator. Also, it was examined by varying the fuel utilization rate and oxygen utilization rate. From the calculation results, we found that as the channel height of the separator decreased, the pressure drop increased exponentially. In addition, it was found that as the channel height of the separator decreased, the gas flow resistance inside the unit cell increased, and the flow resistance increased the pressure drop, thereby improving the flow uniformity inside the stack. Finally, the calculation results showed that as the fuel and oxygen utilization increased, the flow uniformity also improved.

• Tribology and Lubricants
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• 제33권1호
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• pp.1-8
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• 2017

Drag torque reduction in a wet clutch pack is a key aspect of the design process of the dual clutch transmission (DCT) system. In order to reduce the drag torque caused by lubricant shear resistance, recently developed wet clutch pack systems of DCT, as well as automatic transmission and other four-wheel drive (4WD) couplings, frequently utilize wavy wet clutch pads. Therefore, wavy shape of friction pad are made on the groove patterns like waffle pattern for the reduction of drag torque. Additionally, the groove patterns are designed with larger channels at several locations on the friction pad to facilitate faster outflow of lubricant. However, channel performance is a function of the waviness of the friction pad at the location of the particular channel. This is because the discharge sectional area varies according to the waviness amplitude at the location of the particular channel. The higher location of the additional channel on the friction pad results in a larger cross-sectional area, which allows for a larger flow discharge rate. This results in reduction of the drag torque caused by the shear resistance of DCTF, because of marginal volume fraction of fluid (VOF) in the space between the friction pad and separator. This study computes the VOF in the space between the friction pad and separator, the hydrodynamic pressure developed, and the shear resistance of friction torque, by using CFD software (FLUENT). In addition, the study investigates the dependence of these parameters on the location and waviness amplitude of the channel pattern on the friction pad. The paper presents design guidelines on the proper location of high waviness amplitude on wavy friction pads.

• 한국전기전자재료학회논문지
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• 제16권5호
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• pp.424-428
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• 2003

The channel of a superconducting flux flow transistor has been fabricated with plasma etching method using a inductively coupled plasma etching. The ICP conditions then were ICP Power of 450 W, rf chuck power of 150 W, the pressure in chamber of 5 mTorr, and Ar : Cl$_2$=1:1. Especially, over the 5 mTorr, the superconducting thin films were not etched. The channel etched by plasma gas showed the critical temperature over 85 K. The critical current of the SFFT was altered by varying the external applied current. As the external applied current increased from 0 to 12 mA, the critical current decreased from 28 to 22 mA. Then the obtained trans-resistance value was smaller than 0.1 $\Omega$ at a bias current of 40 mA.

• 한국표면공학회지
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• 제48권4호
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• pp.142-148
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• 2015

The effect of equal channel angular pressing (ECAP) on the pitting corrosion resistance of hard anodized Al5052 alloy was investigated. The degree of internal stress generated in anodic oxide films during hard anodization was also evaluated with a strain gauge method. The pitting corrosion resistance of hard anodized Al5052 alloy was greatly decreased by ECAP. Cracks occurred in the anodic oxide film during hard anodization and these cracks were larger and deeper in the alloy with ECAP than without. The pitting corrosion was accelerated by cracks. The internal stress present in the anodic oxide films was compressive and the stress was higher in the alloys with ECAP than without, resulting in an increased likelihood of cracks. The pitting corrosion resistance of hard anodized Al5052 alloy was improved by annealing at the range of 473-573K after ECAP processed at room temperature for four passes. The compressive internal stress gradually decreased with increasing annealing temperature. It is assumed that the improvement in the pitting corrosion resistance of hard anodized Al5052 alloy by annealing may be attributed to a decrease in the likelihood of cracks due to the decreased internal stresses in anodic oxide films.

• 한국해양공학회지
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• 제27권6호
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• pp.1-6
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• 2013

A 25ft class fishing leisure boat is developed, and the resistance performances are investigated by a model test in a high-speed circulating water channel. The design speed of the developed ship is 25 knots using a 150 ps outboard engine. A catamanan type hull form using a planing section is adopted considering the Froude number and large deck area. The effect of a center body attached on the bottom of the cross deck is studied under various conditions. Wave patterns are observed to make clear the relationship between the resistance performance and the wave characteristics. The results show that the shape of the center body and the position of the chine line can have a strong effect on the resistance performance in a certain velocity range.

• 대한전자공학회논문지
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• 제27권11호
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• pp.49-54
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• 1990

본 논문에서는 LDD(lightly doped drain)구조를 갖는 짧은 채널 MOSFET에서의 기생저항의 게이트 전압 의존도에 대한 모형을 제시하였다. 게이트 전극 밑에 위치한 LDD 영역에서는 게이트 전압에 의해 준 이차원적인 축적층(quasi two-dimensional accumulation layer)이 형성된다. 소오스 측 LDD 기생저항을 축적층의 저항과 벌크 LDD 저항의 병렬 연결로 취급하였으며 별크 LDD 저항은 채널의 반전층 끝으로부터 ${n^+}$영역의 경계까지 퍼짐 저항으로 근사하였다. 그리고 접합에서의 도우핑 농도 구배가 LDD 저항에 미치는 영향이 토의하였다. 본 모형의 결과로 선형 영역에서는 LDD 저항이 게이트 전압의 증가에 따라 감소하고, 포화영역에서는 채널과 LDD에서 속도포화를 고려한 결과, 게이트 전압에 대해 준 일차적으로 증가하는 것으나 나타나 발표된 실험결과들과 일치하였다.