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고충격에 신관의 생존성을 향상시키기 위한 다층 충격완충장치 전산해석 연구
소경재,김민겸,이대희,Soh, Kyoung Jae,Kim, Minkyum,Lee, Daehee 한국전산구조공학회 2020 한국전산구조공학회논문집 Vol.33 No.4
This study proposes a method of constructing an effective shock absorber. The existing shock absorber is fabricated only with polyethylene; however, the new shock absorber comprises polyethylene on the outside and a high-density material on the inside. The shock was mostly reduced when the density difference between the inner and outer materials was large. Aluminum, titanium, and copper were chosen as the outer structure of two-layer. Shock reduction was most effective in copper with the highest density, and the maximum deceleration was reduced by 43% while the impulse was reduced by 51% in the proposed shock absorber than the traditional shock absorber. In the cases of four-layer and six-layer shock absorbers, the impulse was reduced, but the maximum deceleration was increased. The fuze must survive from the biggest shock and the remaining shock waves should not exceed the threshold. Thus, a two-layer structure shock absorber using polyethylene-copper was proposed. 본 논문은 충격을 줄이기 위해 효과적인 충격완충장치를 구성하는 방법을 제안했다. 기존의 충격완충장치는 폴리에틸렌으로만 만들어졌지만, 새로운 충격완충장치는 외측에는 폴리에틸렌, 내측에는 고밀도 재료로 구성하였다. 충격은 내측과 외측 물질 사이의 밀도 차이가 더 클 때 줄어들었다. 2층 구조의 외측으로 설계하기 위해 알루미늄, 티타늄, 구리를 선택하였다. 가장 밀도가 높은 구리에서는 충격 감소가 가장 좋았으며, 기존 충격완충장치보다 최대 감가속도는 43%, 충격량은 51% 감소하였다. 4층, 6층 충격완충장치의 경우, 충격량은 줄였지만, 최대 감가속도는 증가하였다. 신관은 가장 큰 충격으로부터 살아남아야 하며 나머지 충격파는 임계값을 초과하지 않으므로, 본 논문은 폴리에틸렌-구리를 사용한 2층 구조용 충격완충장치를 제안하였다.
멘토링을 통한 중등영어 초임교사 수업 전문성 발달 지원에 관한 연구
장경숙 ( Kyungsuk Chang ),김민겸 ( Minkyum Kim ),최보윤 ( Boyoon Choi ) 한국중등영어교육학회 2012 중등영어교육 Vol.5 No.2
This study investigated how secondary English novice teachers`` continuing professional development was pursued through mentoring. Three novice teachers took part as mentee, and 5 experienced teachers and overseas specialists were involved as mentors. Data was gathered through video-taped lessons, observation, interview, and research journals. The data collected from different sources was categorized according to their saliency, frequency and to those recurring patterns found within. The findings revealed that mentoring was given with focus on areas such as the use of mother tongue, learning strategies, teaching objectives, discipline, learning atmosphere, error correction, learning styles, and language skill integration. It was also found that the mentors with different background showed different ways of providing consulting on the novice teachers`` classes observed. Suggestions were made for the effective implementation of novice teacher support program and continuing professional development.