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Study of n/γ Discrimination Using 3He Proportional Chamber in High Gamma-Ray Fields
최준범,박준식,손재범,김용균 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.1
The 3He proportional chamber is widely used for neutron measurement owing to its high neutrondetection efficiency and simplicity for gamma-ray rejection. In general, the neutron and gamma-raysignals obtained from the 3He proportional chamber can be easily separated by the difference in thepulse heights. However, for a high gamma-ray field, the gamma-ray signal cannot be precisely eliminatedby the pulse height due to gamma-ray pulse pileup which causes the pulse height of gamma-ray pulse toincrease and making the pulses due to neutrons and gamma rays indistinguishable. In this study, animproved algorithm for n/g discrimination using a parameter, which is the ratio of the rise time to thepulse height, is proposed. The n/g discrimination performance of the algorithm is evaluated by applyingit to 252Cf neutron signal separation from various gamma-ray exposure rate levels ranging 0.1e5 R/h. Theperformance is compared to that of the conventional pulse-height analysis method in terms of thegamma elimination ratio. The suggested algorithm shows better performance than the conventional oneby 1.7% (at 0.1 R/h) to 70% (at 5 R/h) for gamma elimination.
주기적인 경계조건을 사용하는 수치모사에서 계산영역 크기의 영향
최준범(Choon-Bum Choi),장용준(Yong-Jun Jang),김진호(Jin Ho Kim),한석윤(Seok Youn Han),양경수(Kyung-Soo Yang) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.5
Effect of computational domain size in simulating of periodic obstacle flow has been investigated for the flow past tube banks. Reynolds number, defined by freestream velocity (U∞ ) and cylinder diameter (d), was fixed as 200, and center-to-center distance (P) as 1.5d. In-line square array and staggered square array were considered. Drag coefficient, lift coefficient and Strouhal number were calculated depending on domain size. Circular cylinders were implemented on a Cartesian grid system by using an immersed boundary method. Boundary condition is periodic in both streamwise and lateral directions. Previous studies in literature often use a square domain with a side length of P, which contains only one cylinder. However, this study reveals that the domain size is improper. Especially, RMS values of flow-induced forces are most sensitive to the domain size.
최준범(Junbeom Choi) 한국비교과교육학회 2023 비교과교육연구 Vol.4 No.2
본 연구는 재학생의 특성에 따른 비교과 만족도 차이를 살펴보고 이를 바탕으로 향후 비교과 프로그램을 계획하는데 청사진을 제공하기 위함이다. 이러한 목적을 달성하기 위해, 총 848명의 재학생의 설문을 바탕으로 통계 분석하였으며, 연구 결과는 다음과 같다. 첫째, 현재 참여하고 있는 비교과에 만족하는지에 대한 유 · 무, 거주유형에 따라 통계적으로 유의미한 차이가 있는 것으로 나타났다. 둘째, 재학생의 특성에 따른 항목별 차이를 살펴보면, 프로그램 내용, 강사, 강사의 전문성을 제외한 6개의 항목에서 여학생보다 남학생의 만족도가 높았으며 통계적으로도 유의한 차이가 없었으며, 학년에 따른 차이에서는 활동 장소와 강사의 항목에서 유의한 차이가 있었으며, 단과대는 모든 항목에서 유의한 차이가 없는 것으로 나타났다. 거주유형에 따른 비교과 프로그램 항목별 만족 차이를 살펴보면, 비교과 전반을 제외한 모든 항목에서 통학하는 학생들의 만족도가 높은 것으로 나타났다. 비교과 전반은 기숙사 2관 소속 학생들의 만족도가 상대적으로 높았으며, 통계적으로도 유의한 차이가 있었다. 마지막으로 기숙사에 만족하는 집단일수록 비교과 프로그램에 만족하는 것으로 나타났다. 이러한 결과를 토대로 비교과 성과 지표를 계획하고 차년도 프로그램을 계획하는데 시사점을 제공하였다. The purpose of this study is to examine differences in comparative education satisfaction by student characteristics and to provide a blueprint for planning future comparative education programs. It is also intended to provide a blueprint for planning the future direction of the extra-curricular program based on these results. Statistical analysis was conducted based on questionnaires from a total of 848 students, and the research results are as follows. First, the group that was satisfied with extra-curricular activities in general and with life in the dormitory was found to be more satisfied with the extra-curricular program, and the College of Humanities and Social Sciences had relatively higher satisfaction with the extra-curricular program than other colleges. There was a statistically significant difference in these results. Second, male students' satisfaction was relatively higher than that of female students in six items excluding extra-curricular program content, instructor, and instructor's expertise, and there was a statistically significant difference. In terms of differences by grade, there were statistically significant differences in the activity location and instructor items, and colleges were found to have no significant differences in all items. Third, looking at the difference in satisfaction by extra-curricular program items according to residence type, it was found that students who commute to school from nearby areas had high satisfaction in all items. The satisfaction level of students living in dormitory building 2 was relatively high, and there was a statistically significant difference. Based on these results, extra-curricular program performance indicators were planned and implications were provided for planning the extra-curricular program for the next year.
ZVS Active Clamp 포워드 컨버터를 적용한 철도차량용 전원공급장치
오효석,장진영,최준범,김재문 대한전기학회 2024 전기학회논문지 Vol.73 No.1
As railway vehicle technology continues to advance and the quantity and performance of electrical and electronic components increase, the required load capacity is also increasing significantly. In response, we propose a 300W class power supply with high reliability. An active clamp forward converter is applied as the SMPS circuit of the power supply to minimize power loss and heat generation through Zero Voltage Switching(ZVS) control. Additional protection circuits were implemented to enhance the durability and reliability of the device, taking into account the challenging operating environment of railway vehicles. In this paper, a prototype was constructed based on the designed active clamp forward converter. The test was conducted, considering the input voltage fluctuation situation in the railroad vehicle, and it was confirmed that the power supply stably outputs DC 12V power. Additionally, the reliability of the 300W class power supply design was further verified through a load test using an electronic load.