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중생대 화강암을 이용한 한국산 지질 표준물질 제작을 위한 예비연구
진미은,선광민,박상구,좌용주 한국지구과학회 2017 韓國地球科學會誌 Vol.38 No.6
In this study, we selected three representative granite samples and conducted petrological observation to establish the Korean geostandards. Samples were taken from the two Jurassic (KJG-1, KJG-2) and one Cretaceous (KCG-1) granites in South Korea. The powder samples were prepared by the standard pulverization process, and glass beads were made for geochemical analysis using X-ray fluorescence (XRF) method, and finally, major element contents of the samples were acquired. The analytical data are shown with mean, standard deviation and relative standard deviation. The accuracy of the analysis was confirmed within an estimated error range of about 5% by comparing the recommended true values of the USGS and GSJ geostandards. Also, we checked the analytical precision by calculating a relative standard deviation of about 3% from the XRF analytical results for the three samples. 본 연구에서는 국내 암석을 대표할 수 있는 한국산 지질 표준물질을 제작하기 위해 대상이 되는 시료를 선정하고암석학적 연구를 실시하였다. 지질 표준물질 대상 암석으로 쥐라기 화강암인 KJG-1와 KJG-2와 함께 백악기 화강암인KCG-1을 선정하였다. 표준적인 분쇄 과정을 통하여 분말시료를 제조하고, X-선 형광을 위한 유리 비드를 제작하였으며, 최종적으로 시료들의 주성분 원소함량을 구하였다. 분석 자료에는 평균, 표준편차 및 상대 표준편차를 함께 제시하였다. 미국지질조사소(USGS)와 일본지질조사소(GSJ)의 지질표준물질을 함께 분석하여 그들의 참값과의 비교를 통해 5% 내의정확도를 확인하였으며, 세 시료에 대한 XRF 분석결과 상대표준편차가 3% 내외의 높은 정밀도 역시 확인하였다.
Turn-off Time Improvement by Fast Neutron Irradiation on pnp Si Bipolar Junction Transistor
안성호,선광민,백하니 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.2
Long turn-off time limits high frequency operation of Bipolar Junction Transistors (BJTs). Turn-off timedecreases with increases in the recombination rate of minority carriers at switching transients. Fastneutron irradiation on a Si BJT incurs lattice damages owing to the displacement of silicon atoms. Thelattice damages increase the recombination rate of injected holes with electrons, and decrease the holelifetime in the base region of pnp Si BJT. Fast neutrons generated from a beryllium target with 30 MeVprotons by an MC-50 cyclotron were irradiated onto pnp Si BJTs in experiment. The experimental resultsshow that the turn-off time, including the storage time and fall time, decreases with increases in fastneutron fluence. Additionally, it is confirmed that the base current increases, and the collector currentand base-to-collector current amplification ratio decrease due to fast neutron irradiation