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Compact ECR plasma장치의 제작 및 특성 연구
윤민기,박원일,남기석,이기방 대한전자공학회 1994 전자공학회논문지-A Vol.31 No.4
A compact electron cyclotron resonance(ECR) plasma system composed of a microwave generator and a magnet coil was fabricated. A Langmuir single probe was used to investigate the plasma characteristics of the system through I-V measurements. The performance of the compact ECR plasma system was tested for the case of silicon etching reaction with $CF_{4}/O_{2}$(30%) mixed gas. Electron density and etch rate increased to maximum values and then decreased with increasing argon gas pressure, but electron temperature changed in the opposite way. The electron density and the electron temperature of argon gas plasma were 0.85${\times}~5.5{\times}10^{10}cm^{-3}$ and 4.5~6.0 eV, respectively, in the pressure range from $3{\times}10^{4}$ to 0.05Torr. The etch rate reached a maximum value at the position of 2.5cm from the bottom of plasma cavity. Etch rate uniformity was $\pm$6% across 6cm wafer. Anisotropic index was 0.75 at 1.5${\times}10^{-4}$Torr.
육상 수조식 양식장의 해수 열원 히트펌프 시스템 적용을 위한 열부하 분석
윤민기,김태훈,정석권,Min-Gi YOON,Tae-Hoon KIM,Seok-Kwon JEONG 한국수산해양기술학회 2023 수산해양기술연구 Vol.59 No.2
This study deals with the maximum thermal load analysis and optimal capacity determination method of tank culture system for applying seawater source heat pump to save energy and realize zero energy. The location of the fish farm was divided into four sea areas, and the heat load in summer and winter was analyzed, respectively. In addition, two representative methods, the flow-through aquaculture system and the recirculation aquaculture system were reviewed as water treatment methods for fish farms. In addition, the concept of the exchange rate was introduced to obtain the maximum heat load of the fish farms. Finally, power consumption for heat pumps was analyzed in the view point of sea areas, tank capacity, and exchange rate based on the calculated maximum thermal load.
가변속 냉동시스템의 정밀 온도 제어를 위한 다입․출력 모델예측 제어기 설계
윤민기,정석권 대한설비공학회 2024 설비공학 논문집 Vol.36 No.4
본 연구에서는 VSRS 기반 오일쿨러 시스템의 강인하고 정밀한 온도 제어를 위해 MPC를 설계하였다. 주요 설계 파라미터인 예측 출력 수 와 예측 입력 수 를 오일출구온도 의 과도 특성을 분석하여 적절한 값으로 선정하였다. 설계된 MPC는 조작기의 물리적 제약조건 하에서 예측 추종 오차와 제어입력 변화량으로 이루어진 목적함수를 최소화하여 최적의 제어입력을 도출하였다. 지령값 변경 및 열부하 증․감 시뮬레이션 및 실험 결과, MPC는 오일출구온도 를 엄밀하게 제어하였으며, 인버터 주파수 의 간섭 영향을 예측하여 과열도 의 오차를 최소화하는 EEV 개도 지령 를 인가하였다. 최종적으로 Dual SISO 기반 PI 제어기와의 제어성능 비교를 통해 설계한 MPC의 유효성을 확인하였다. 본 연구의 주요 결론을 요약하면 다음과 같다. (1) MPC는 오일출구온도 를 목표 온도에 엄밀히 추종시켰고, 스텝 상의 외란 인가에 대해서도 허용 오차 범위 ±0.1℃ 이내의 강인한 온도 제어를 실현하였다. (2) MPC 설계 시 예측 출력 수 는 시스템의 미래 상태 예측을 위해 적절하게 큰 값을, 예측 입력 수 는 제어기의 과도한 계산 부담을 줄이기 위해 적절하게 작은 값을 선정해야 한다. (3) 목적함수의 예측 오차 에 부가된 감쇠 행렬 은 온도 계측 센서의 열잡음으로 인한 과도한 예측 출력을 막고, 제어성능의 열화를 방지하는 데 기여하였다. (4) MPC는 예측 방정식을 통해 간섭 영향을 예측하여 제어하므로 Dual SISO 기반 PI 제어기와의 비교에서 와 를 모두 더 빠르고 정밀하게 제어하였다. Variable speed refrigeration systems are composed of multiple input multiple output systems with several state variables. These input/output variables and state variables typically have various constraints, making it challenging to design optimal control considering these constraints. However, model predictive control (MPC) has been gaining attention in process control recently due to its ability to optimally control a multi-input multi-output system with a number of constraints and early constraints reflection. It can predict future outputs while taking into account current constraints through quadratic programming optimization with a mathematical algorithm. Subsequently, it can determine the optimal control input. To verify the validity of MPC, the control performance of MPC was compared with conventional PI control satisfying constraints through Matlab simulation and experiment on the oil cooler system.
윤민기(Min Gi Yoon),정석권(Seok Kwon Jeong) 대한설비공학회 2022 대한설비공학회 학술발표대회논문집 Vol.2022 No.11
Variable speed refrigeration systems (VSRS) are mostly composed of multiple input/output systems with multiple state variables. In particular, since input/output variables and state variables have various constraints in an actual system, it is not easy to design an optimal control considering them. Model predictive control (MPC) has recently been attracting attention in process control due to the advantage of being able to optimally control a MIMO system having a number of constraints. Above all, MPC exhibits excellent control performance because it predicts future outputs reflecting constraints at the present time and determines the optimal control input. In this study, we apply MPC to VSRS and examine their effectiveness through Matlab simulation. In the simulation, to confirm MPC validity, control performance of MPC considered with early reflection of constraints is compared with conventional PI control satisfying constraints through saturation.
흥미영상 : Tc-99m-가열처리 적혈구 스캔에서 다발성 복막비증
윤민기 ( Min Ki Yoon ),황경훈 ( Kyung Hoon Hwang ),최원식 ( Won Sick Choe ) 대한핵의학회 2006 핵의학 분자영상 Vol.40 No.3
A 44-year-old man with a past medical history of splenectomy came to hospital because of epigastric pain. Abdominopelvic computed tomography(CT) showed a soft tissue mass and multifocal variable-sized nodules as well as findings suggestive of cholecystitis. Subsequently, he underwent Tc-99m-labeled heat-denatured red blood cell(RBC) scintigraphy to evaluate the mass and nodules. The scintigraphy confirmed multifocal peritoneal splenosis in the abdominopelvic cavity. (Nucl Med Mol Imaging 2006;40(3):190-191)