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Deep Submicron MOSFET 기판회로 파라미터의 바이어스 및 게이트 길이 종속 데이터 추출
이용택,최문성,구자남,이성현,Lee Yongtaek,Choi Munsung,Ku Janam,Lee Seonghearn 대한전자공학회 2004 電子工學會論文誌-SD (Semiconductor and devices) Vol.41 No.12
The study on the RF substrate circuit is necessary to model RF output characteristics of deep submicron MOSFETs below 0.2$\mum$ gate length that have bun commercialized by the recent development of Si submicron process. In this paper, direct extraction methods are developed to apply for a simple substrate resistance model as well as another substrate model with connecting resistance and capacitance in parallel. Using these extraction methods, better agreement with measured Y22-parameter up to 30 GHz is achieved for 0.15$\mum$ CMOS device by using the parallel RC substrate model rather than the simple resistance one, demonstrating the RF accuracy of the parallel model and extraction technique. Using this model, bias and gate length dependent curves of substrate parameters in the RF region are obtained by increasing drain voltage of 0 to 1.2V at deep submicron devices with various gate lengths of 0.11 to 0.5㎛ These new extraction data will greatly contribute to developing a scalable RF nonlinear substrate model. 최근 실리콘 미세공정의 발달로 상용화된 0.2$\mum$ 게이트길이 이하의 deep submicron MOSFET 출력특성을 정확히 모델링하기 위해서는 RF 기판 회로 연구가 필수적이다. 먼저 본 논문에서는 기판 캐패시던스와 기판 저항이 병렬로 연결된 모델과 기판 저항만을 사용한 단순 모델들에 적합한 직접 추출 방법을 각각 개발하였다. 이 추출방법들을 0.15$\mum$ CMOS 소자에 적용한 결과 단순 모델보다 RC 병렬 기판모델이 측정된 $Y_{22}$-parameter에 30GHz까지 더 잘 일치하는 것을 확인하였으며, 이는 RC 병렬 기판모델 및 직접추출방법의 RF 정확도를 증명한다. 이러한 RC 병렬 기판모델을 사용하여 게이트 길이를 0.11에서 0.5$\mum$까지 변화시키고 드레인 전압을 0에서 1.2V까지 증가시키면서 기판 모델 파라미터들의 bias 종속 특성과 게이트 길이 종속 특성을 새롭게 추출하였다. 이러한 새로운 추출 결과는 scalable한 RF 비선형 기판 모델 개발에 유용하게 사용될 것이다.
댐 운영 제약사항을 고려한 섬진강댐 홍수조절방식에 관한 연구
이용택,정관수,Lee, Yongtaek,Jung, Kwansue 한국수자원학회 2024 한국수자원학회논문집 Vol.57 No.4
Climate change has intensified the severity of extreme floods, presenting substantial challenges to dam management and operation. Traditionally, flood control strategies for dam operations have been based on theoretical scenarios, such as designed floods, without taking into account downstream conditions. However, in practice, managing floods involves operating dams based on climate forecasts. This strategy encounters challenges due to the limited predictability of climate forecasts, which in turn leads to uncertainty in decisionmaking among dam managers. This study proposes a flood control approach for dam operations that involves gradually increasing the outflow, considering the operational constraints and potential downstream damage, based on inflow data. The effectiveness of this method was assessed through simulation, employing both a designed flood and data from the most significant historical flood. The dam operation strategy for flood control presented in this study provides a framework for dam operators, facilitating consistent decisionmaking in flood management by integrating realistic dam operational conditions.
MSP 기법을 적용한 고분자 전해질 연료전지 가스확산층의 포로시메트리 연구
이용택(Yongtaek Lee) 대한설비공학회 2013 설비공학 논문집 Vol.25 No.2
The structure of pore network of gas diffusion layers (GDLs) in PEMFCs plays a critical role in determining the transport phenomena of reaction gas as well as generated water. In addition, the interactive characteristics between water and surface of pore are no less important than the structural characteristics of pore network. In this study, porometric investigation is conducted for two kinds of GDL using method of standard porosimetry which enable to distinguish hydrophobic pores from hydrophilic pores of GDLs. The porosity of TGPH-120 decreases by 6% by adding 30 wt.% of PTFE, but the porosity of hydrophilic pores decreases by 12%. The relation of pc-Snw varies with the addition of PTFE, especially at low pc.
고분자 전해질 연료전지의 외부가습 조건에 따른 정상상태 및 비정상상태 성능특성 연구
이용택(Yongtaek Lee),김보성(Bo Sung Kim),김용찬(Yongchan Kim),최종민(Jong Min Choi),고장면(Jang Myoun Ko) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
The performance characteristics of the polymer electrolyte fuel cells (PEFCs) were investigated under various humidification conditions at steady-state and transient conditions. The PEFC studied in this study was characterized by I-V curves in potentiostatic mode. The I-V curves representing steady-state performance were obtained from OCV to 0.25V, and the dynamic performance responses were obtained at some points of voltages. The anodic external humidification was applied and the humidity was controlled from 20% to 100%. The effects of relative humidity of hydrogen were measured with the dry air at the cathode. At high voltage region, the performance at high temperature was higher, but at low voltage region, low temperature condition showed the higher performance. The dynamic responses were observed at the instant when the voltage of the PEFC was changed. It was observed that the performance reached steady-state earlier with the increase of temperature.
채널 내장형 습도 센서를 이용한 고분자 전해질 연료전지의 습도분포 측정
이용택(Yongtaek Lee),양경열(Gyung Yull Yang) 대한기계학회 2015 大韓機械學會論文集B Vol.39 No.5
본 연구는 고분자 전해질 연료전지 (PEMFC)의 성능에 매우 중요한 영향을 미치는 물의 분포를 실험적으로 측정하였다. 내부에서 일어나는 활발한 화학반응과 물질전달 특성 때문에 PEMFC 내부에서 수분의 분포가 불균일하며 그 분포를 실험적으로 측정하기가 용이하지 않아 그 동안 간접적인 측정이 많이 이루어졌다. 본 연구에서는 초소형 온습도 센서를 연료전지의 채널에 직접 삽입하고 채널을 따라 흐르는 반응가스의 습도를 측정하였다. 수소극과 공기극 중 한곳만 가습하며, 가습하지 않은 곳에서 습도를 측정하여 멤브레인을 통한 물의 이동을 연구하였다. 가습기의 온도가 증가할수록 양극의 물농도구배가 커져서 확산이 증가하나 높은 전류밀도에서는 전기삼투항력의 영향이 더욱 커졌다. In this study, water distribution inside a proton exchange membrane fuel cell (PEMFC) was measured experimentally. Water distribution is non-uniform because of vigorous chemical reaction and mass transport and has been difficult to measure experimentally. Therefore, much research relied on indirect measuring methods or numerical simulations. In this study, several mini temperature-humidity sensors were installed at the channel for measuring temperature and humidity of the flowing gas throughout the channel. Only one of two electrode channels was humidified externally, and the humidity distribution on the other side was measured, enabling the observation of water transport characteristics under various conditions. Diffusion through the membrane became more vigorous as the temperature of the humidifier rose, but at high current density, electro-osmotic drag became more effective than diffusion.
이용택(Yongtaek Lee),이원희(Wonhee Lee),장하늘(Haneul Jang) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
A CO₂ incubator is a device used for culturing, growing, and maintaining cells or microorganisms, and it is necessary to precisely maintain the optimum temperature, humidity, and CO₂ concentration in the internal atmosphere for cell growth. Through the benchmarking of the existing CO₂ incubator, internal flow and transient heat transfer were observed through computational analysis. Variation of the temperature distribution inside the chamber was observed when the air was heated from the 6 sides surrounding the chamber. After 8 seconds from the start of heating, the vicinity of the wall was heated to 67 ℃, but the temperature of the tray on which the sample would be placed did not reach the target temperature of 37 ℃. It is expected that the results of this study will be utilized in determining the control logic of the heating unit and the temperature measuring location during product development.