The conservative method on the analysis of loss-of-coolant accidents for the HANARO fuel test loop was established based on the guide of evaluation method for the emergency core cooling systems of pressurized light water reactors. The evaluation models, the Moody model for discharge rate calculation and the Baker-Just model for water-metal reaction calculation, were used. In order to calculate conservative peak cladding temperatures for accidents the multipliers to the correlations of heat transfer coefficients in the MARS were also introduced. Consequently it is found that the maximum peak cladding temperature predicted by using the conservative method is sufficiently greater than that calculated by using the best-estimated models.
반도체 직접회로 패키지에서, 실리콘 칩의 탑 표면은 양면 리드 프레임 영역에서 바로 붙게 된다. 여기서, 양면이란 베이스 층에 상위 접착층과 하위 접착층으로 되어 있음을 말한다. IC 패키지 구조는 탈 라미네이트 화와 같이 열-기계적 파손 모드로 나타나게 된다고 알려져 왔다. 이 파손 모드의 원인은 실리콘 칩 접착면의 잔류응력 과 냉간 숙성 공정 내에 리드 프레임으로 인해 일어난다. 숙성 공정 내 유도된 열응력은 실리콘 칩과 리드 프레임위에 냉간 잔류 응력에 영향을 가진다.
본 연구에서는 칩 표면 손상의 최소화를 위해서, 실리콘 칩 위에 접착 위상 최적화 방법들이 유한 요소 해석(Finite Element Analysis)을 통해 연구되었다
미세 위치제어를 위한 미세 산업용 로봇의 작업물의 정도 보정을 위해 마이크로 조정기가 고안되었다. 피에조전기 엑추에이터를 이용한 능동 메커니즘을 증폭시키기 위한 메커니즘 설계는 위상 최적설계와 형상 최적설계의 진일보를 위해서 기하학적으로 구조적으로 둘 다 필요하다. 메커니즘의 총괄적인 기하학적 장점과 기계적 효율이 객관적성능으로서 고려되었으며, 이는 입력의 힘분에 출력의 변위, 지지발의 수직 운동과 조정기의 구조 강성의 각각의 비이다. 이들 목적함수를 최대화하기 위하여, 순차 선형 프로그램최적 기준법이 위상 재료 분포, 능동 구조물과 굽힘힌지의 기하학적 차원을 위해 사용되었다. 이 연구는 메커니즘의 능동성을 최대화 할 뿐 아니라, 위치도의 정확도와 충분한 작업공간을 보장하는 종합적 설계 공정을 보여준다. 실험은 역학적, 구조적 성능의 비교를 통해 설계공정을 유효화하기 위해 시행되었다
The initial hull form having a 3 gross tonnage and 30 knots class high speed leisure boat is newly developed based on a statistical analysis method. Fluid dynamics characteristics are studied by commercial CFD code, FLUENT. The effect of a fin attached on the hull side is investigated together. It can be found that the fin plays a role of increasing the resistance performan
The agitator with a reducer are usually using on the process of a water treatment. However, working the reducer at the field, a lubricant oil can leak out. It causes an environment pollution and a water service/sewerage pollution problem. In this study, the reducer with a drywell structure is developed in order to prevent the oil leakage. The drywell structure is that the reducer bottom housing and the support column of an output shaft are united, and taper roller bearings are in the bottom housing. During the development of the reducer, a mockup and a prototype are made by using CAD and a high speed CNC machine. Then, to prove the performance of the prototype, the performance tests, unload working test and the mechanical torque efficiency test, are conducted by the torque meter device. Also a motor velocity(rpm) control system is developed by a PID control according to the working loads(MLSS data). The results of the test are shown that the maximum torque efficiency is 88.45%, the oil leakage and the abnormal noise do not occur during the work. Therefore the reducer with the drywell structure and the motor rpm PID control system is successfully developed.
This technology is to highly produce heat by microorganism during fermentation of mushroom sludge as a byproduct at farm field which would be established more competitive in mushroom growers and distinguished technology with ordinary mushroom growers. Furthermore this technology could be reduced energy as well as high efficiency in resource uses. There was highly reduction in energy consumption using by heat during fermentation of mushroom sludge which was produced by different media material with vegetable for mushroom cultivation. After 4 days the inner temperature during fermentation of mushroom media was a little changes of 61～50℃ and inner temperature of fermentation chamber was 55～45℃, inlet temperature of cooling water was 17℃, outlet temperature was 44～35℃, and ambient temperature was 28℃ at daytime and 14℃ at night time which was relatively constant. A heat exchange from fermentation chamber was 1090～648㎉/10min and the maximum heat exchange was 11550～1064㎉/10min which was caused to reduce fermentation heat with time The efficiency of heat exchange was distributed with 81～61% with time.