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수술 받은 과거력이 없는 고령 환자에 발생한 횡행결장간막 탈장 1예
박훈석 ( Hoon Suk Park ),김진일 ( Jin Il Kim ),김명석 ( Myoung Seok Kim ),김순섭 ( Soon Sub Kim ),조세현 ( Se Hyun Cho ),박수헌 ( Soo Heon Park ),한준열 ( Joon Yeol Han ),김재광 ( Jae Kwang Kim ) 대한소화기학회 2006 대한소화기학회지 Vol.48 No.4
Internal hernia is defined as the herniation of viscera through an anatomic or pathologic opening within the boundaries of peritoneal cavity. Transmesocolic hernia, a subtype of internal hernia, has a herniated sac through the transverse mesocolon. Transmesocolic hernia has been rarely described in the literature, and most of reported cases were associated with a history of operation or congenital anormaly. A 72-year-old female with chronic intermittent abdominal pain and bloating was admitted. Small bowel series showed multiple jejunal loops confined to the left upper quadrant of abdomen. Abdomen spiral computed tomography (CT) showed a cluster of mildly dilated small bowel loops with mesenteries on the same area. On the three-dimensional reconstruction CT scan, a herniated sac through the transverse mesocolon was identified. She was diagnosed as transmesocolic hernia by using the three-dimensional reconstruction CT and small bowel series, without surgical exploration. The symptoms were managed with conservative measures. (Korean J Gastroenterol 2006;48:286-289)
Synthetic jet을 이용한 승용차의 공력저항 감소에 대한 실험적 연구
박훈일(Hoon-Il Park),이영빈(Youngbin Lee),강승온(Seung-On Kang),송기선(Ki-Sun Song),기정도(Jung-Do Kee),이준호(Jun-Ho Lee),정형석(Hyoung-Seog Chung),장영일(Young Il Jang),김규홍(Kyu-Hong Kim),이동호(Dong-Ho Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
This paper describes drag reduction of a passenger car by using synthetic jet in wind tunnel test. For the reduction of aerodynamic drag, 11 synthetic jets are installed at the edge of the trunk on a 1/4 scale passenger car model to control the separation of the flow. Aerodynamic drag reduction is observed according to the jet location, jet direction and jet driving frequency. However, in case of the trunk sideward jet, aerodynamic drag is increased. As a result, drag reducing jet location, jet direction and jet driving frequency are revealed and it shows the possibility of aerodynamic drag reduction of a passenger car can be achieved by the synthetic jet.
기존선 고속화를 위한 180㎞/h급 준고속 틸팅차량의 차량 하부열차풍 특성 분석
윤수환(Yun Su-Hwan),박훈일(Park Hoon-Il),곽민호(Kwak Min-Ho),고태환(Ko Tae-Hwan),이동호(Lee Dong-Ho) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월
Increase of travelling speed of train induces high speed underbody flow, and this can cause aerodynamic problem such as ballast-flying phenomena. In this study underbody flow characteristics of Korean Tilting Train Express(TTX) is investigated by field measurement test, which can travel at 180㎞/h in existing line. Test performed at open field, tunnel section and grade section. In each case measurement performed along the transverse sleeper. Underbody flow speed is obtained differently with the location of the measurement point along the transverse sleeper. In tunnel section test, this difference is reduced. In grade section, underbody flow speed appeared in the order of center, inside of curvature, and outside. Result of this research can be used as a basis for improving safety of train and passengers.
모터구동 회로 응용을 위한 대전력 전류 센싱 트렌치 게이트 MOSFET
김상기(Sang-Gi Kim),박훈수(Hoon-Soo Park),원종일(Jong-Il Won),구진근(Jin-Gun Koo),노태문(Tae-Moon Roh),양일석(Yil-Suk Yang),박종문(Jong-Moon Park) 한국전기전자학회 2016 전기전자학회논문지 Vol.20 No.3
본 논문은 전류 센싱 FET가 내장되어 있고 온-저항이 낮으며 고전류 구동이 가능한 트렌치 게이트 고 전력 MOSFET를 제안하고 전기적 특성을 분석하였다. 트렌치 게이트 전력 소자는 트렌치 폭 0.6 ㎛, 셀 피치 3.0 ㎛로 제작하였으며 내장된 전류 센싱 FET는 주 전력 MOSFET와 같은 구조이다. 트렌치 게이트 MOSFET의 집적도와 신뢰성을 향상시키기 위하여 자체 정렬 트렌치 식각 기술과 수소 어닐링 기술을 적용하였다. 또한, 문턱전압을 낮게 유지하고 게이트 산화막의 신뢰성을 증가시키기 위하여 열 산화막과 CVD 산화막을 결합한 적층 게이트 산화막 구조를 적용하였다. 실험결과 고밀도 트렌치 게이트 소자의 온-저항은 24 mΩ, 항복 전압은 100 V로 측정되었다. 측정한 전류 센싱 비율은 약 70 정도이며 게이트 전압변화에 대한 전류 센싱 변화율은 약 5.6 % 이하로 나타났다. In this paer, low on-resistance and high-power trench gate MOSFET (Metal-Oxide-Silicon Field Effect Transistor) incorporating current sensing FET (Field Effect Transistor) is proposed and evaluated. The trench gate power MOSFET was fabricated with 0.6 ㎛ trench width and 3.0 ㎛ cell pitch. Compared with the main switching MOSFET, the on-chip current sensing FET has the same device structure and geometry. In order to improve cell density and device reliability, self-aligned trench etching and hydrogen annealing techniques were performed. Moreover, maintaining low threshold voltage and simultaneously improving gate oxide relialility, the stacked gate oxide structure combining thermal and CVD (chemical vapor deposition) oxides was adopted. The on-resistance and breakdown voltage of the high density trench gate device were evaluated 24 mΩ and 100 V, respectively. The measured current sensing ratio and it’s variation depending on the gate voltage were approximately 70:1 and less than 5.6 %.
Vehicle Modeling Function으로 구현한 3차원 승용차의 후면 형상 변형이 공력성능에 미치는 영향에 관한 Parametric Study
송기선(Ki-Sun Song),강승온(Seung-On Kang),박훈일(Hoon-Il Park),이준호(Jun-Ho Lee),기정도(Jung-Do Kee),김규홍(Kyu-Hong Kim),이동호(Dong-Ho Lee) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
This paper conducts a parametric study on the overall tendencies of changes of aerodynamic characteristics of a sedan depending on the rear body shape modifications through CFD simulation. In these research, the shapes of YF SONATA are represented by vehicle modeling function(VMF) which can generate and change the shapes of YF SONATA very quickly, compared with the realistic complicated model. The vehicle modeling functions are improved; several section functions and variables are added in order to generate the rear body shapes in detail. And the tendency of changes of the aerodynamic characteristics is analyzed. Finally, this paper suggests that the 3D shape of YF SONATA represented by VMF can reduce the overall time cost in designing a car because it takes so less time to know the ultimate car’s aerodynamic performance through proving the overall tendencies of the shape represented by VMF and the rear shape are very similar.
Vehicle Modeling Function 으로 구현한 3차원 자동차 모델 주위의 유동 시뮬레이션 및 공력성능예측
강승온(Seung-On Kang),전상욱(Sang-Ook Jun),박훈일(Hoon-Il Park),구요천(Yo-Cheon Ku),기정도(Jung-Do Kee),김규홍(Kyu-Hong Kim),이동호(Dong-Ho Lee) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
The objective of this study is Computational Fluid Dynamics (CFD) flow simulation and aerodynamic performance prediction around three dimensional automobile configuration represented by Vehicle Modeling Function (VMF). For performing CFD analysis of three-dimensional automotive vehicle configuration, 3D virtual automobile shape is needed in the initial stage . In this study, VMF is mathematically defined in the form of an exponential function to smoothly express the complex 3D curved shapes of an automotive vehicle. Then CFD analysis is performed to simulate and analyze the characteristics of the flow field over the external configuration of the 3D virtual automobile model. Finally, aerodynamic performance is predicted and discussed considering the external configuration, wheel arch, rotating wheel and moving ground effects.
승용차의 공기저항 감소를 위한 외부유동 시뮬레이션 분석
송기선(Ki-Sun Song),강승온(Seung-On Kang),박훈일(Hoon-Il Park),기정도(Jung-Do Kee),김규홍(Kyu-Hong Kim),이동호(Dong-Ho Lee) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
When a passenger car cruises, the characteristics of external fluid flows which pass near the car body vary depending on the aerodynamic shape of the car so that many kinds of aerodynamic drags occur as the results of this phenomenon. According to previous researches, it is well known that the aerodynamic drag affects the fuel efficiency of a car directly. Although this factor has played a powerful motivation for many researchers to conduct many cases of studies on reducing the aerodynamic drag of cars by using CFD simulations, it is true that the quality of the reliability of the CFD results was not reasonable because of the excessive simplifications of the car body shapes. For this reason, in order to overcome and reduce these kinds of limits, a feasibly meshed car body shape of YF SONATA of Hyundai Motors Company for CFD analysis was suggested and the aerodynamic characteristics were studied comprehensively by CFD analysis so that it was analyzed how the external fluid flows around the car body affect the aerodynamic characteristics of the car.
능동형 리어 디퓨져 장치의 형상이 자동차 공기저항 감소 효과에 미치는 영향에 대한 연구
조준호(Jun-Ho Cho),강승온(Seung-On Kang),박훈일(Hoon-Il Park),송기선(Ki-Sun Song),기정도(Jung-Do Ki),이준호(Jun-Ho Lee),김규홍(Kyu-Hong Kim),이동호(Dong-Ho Lee) 한국자동차공학회 2012 한국자동차공학회 부문종합 학술대회 Vol.2012 No.5
The main purpose of this paper is to examine the Influence of active translating rear diffuser configuration to aerodynamic drag reduction of automotive vehicle. Actively translating rear diffuser reduces aerodynamic drag of a fast cruising car. Actively translating rear diffuser is hidden under the trunk when a car is parked and is driven slowly. And it slides out from under rear car body only at high speed driving condition not to ruin the external design of the car. 10 types of rear diffuser devices whose configuration is different were installed under the car body and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. Finding a configuration which shows the best aerodynamic drag reduction performance is to explain the aerodynamic drag reduction mechanism of a car cruising at a high speed via an actively translating rear diffuser device. The diffuser device blocks low pressure underbody flow and raises pressure of it with diffusing process and then underbody flow and upperbody flow mix strongly, bringing about an aerodynamic drag reduction. Finally, aerodynamic drag of the car is reduced by an average of more than 7% with plate arc type diffuser, which helps to improve the fuel efficiency.
승용차의 공기저항 감소를 위한 후면 형상의 공력 최적설계
송기선(Ki-sun Song),강승은(Seung-on Kang),전상욱(Sang-ook Jun),박훈일(Hoon-il Park),기정도(Jung-do Kee),김규홍(Kyu-hong Kim),이동호(Dong-ho Lee) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
This study proposed an aerodynamically optimized outer shape of a sedan using Artificial Neural Network (ANN) and focused its attention on modifying the rear body shapes of the sedan. To determine the optimization variables, the unsteady flow field around the sedan cruising very fast was scrutinized by CFD simulation, and thereby, the fluctuations of the drag coefficient (CD) and pressure around were confirmed. Regarding the baseline result for CFD, 6 local parts of the end from the sedan were chosen as the design variables for the optimization. Moreover, the ANN approximation model was established with 64 experimental points generated by the D-optimal methodology. As a result, an aerodynamically optimized shape for the rear end of the sedan in which the drag was minimal was proposed with its aerodynamic performance improving by about 5.517%, compared with that of the baseline. Finally, it is expected that in the proper range of shape modifications for a rear body, the aerodynamic performance of a sedan can be enhanced, and thereby, the fuel efficiency of the sedan can be improved. The YF SONATA, a sedan manufactured by Hyundai Motors Company, played a major role in this research as the baseline vehicle.