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철갑소이탄에 의한 전투시스템 내 적재포탄의 순간화재에 관한 전산해석
이승철(Lee, Seung-Cheol),전우철(Jeon, U-Cheol),이해평(Lee, Hae-Pyeong),이헌주(Lee, Heon-Ju) 한국화재소방학회 2013 한국화재소방학회 학술대회 논문집 Vol.2013 No.추계
본 연구에서는 철갑소이탄이 장갑을 관통한 후 전투시스템 내의 적재포탄(고폭탄 또는 추진제)에 피탄되었을 때 순간화재 발생확률에 대해 전산해석을 수행하였다. 장갑은 RHA 재질로 설정하였고, 장갑 두께를 5~30 mm까지 5 mm씩 증가시키며 전산해석을 실시하였다. 고폭탄은 COMPB, TNT, PBX가 사용되었으며 추진제는 ANB가 사용되었다. 본 해석은 Autodyn 프로그램을 사용하였으며, 순간화재 발생 여부를 해석하기 위해 Lee-Tarver ignition and growth model을 사용하였다. 해석 결과, 철갑소이탄이 고폭탄 TNT와 PBX에 피탄되었을 때, 순간화재 발생확률이 모두 100%를 나타내었으며, 고폭탄 COMPB의 경우, 0.8~0.08%로 나타났다. 추진제 ANB의 순간화재 발생확률은 3.8~3.6%로 나타났다.
여운철,조광현,이유신,허대석,이승철 ( Un Cheol Yeo,Kwang Hyun Cho,Yoo Shin Lee,Dae Seog Heo,Seung Chul Lee ) 대한피부과학회 1990 대한피부과학회지 Vol.28 No.5
A Case of Erythema Multiforme A ssociated with Malignant Lymphoma Un Cheol Yeo, M.D., Kwang Hyun Cho, M.D., Yoo Shin Lee, M.D., Dae Seog Heo*, M.D., Seoung Chul Lee**, M.D Department of Dermatology and Internal Medicine*, College of Medicine, Seoul National University, Seoul, Korea, Department of Dermatology**, College of Medicine, Inha University, Kyung Gi Do, Korea We report a case of erythema multiforme associated with malignant lymphoma. Fifty-six-year-old male patient visited our clinic complaining generalized skin lesions which were compatible with erythema multiforme clinically and histopathologically. The skin lesions were treatment-resistant, recurrent and persistent for 3 years. In consideration of old age, atypical features of erythema multiforme and no other demonstrable etiology of erythema multiforme, we studied for internal malignancy. Malignant lymphoma at the duodenum was revealed by UGI series, abdominal CT, and endoscopic biopsy. After chemotherapy, the tumor mass and active skin lesions were cleared simultaneously. Erythema multiforme may be regarded as one of the paraneoplastic syndromes.
FFA 베이시스위험 축소를 위한 용선료 지급기준 변경의 타당성 검토
이승철,윤희성,Lee, Seung-Cheol,Yun, Heesung 한국항해항만학회 2022 한국항해항만학회지 Vol.46 No.4
FFA는 1990년대 초반 이후 시장위험의 헤징을 위한 유효한 수단으로 대두되었지만 베이시스위험으로 헤징의 효과성이 크게 저해될 수 있다는 점과 현금흐름의 불일치 등이 활성화의 장애요인으로 지적된다. 본 연구는 FFA의 헤징효과에 영향을 미치는 베이시스위험에 대하여 분석하고 이를 축소하기 위한 대안을 제시한다. 베이시스위험은 시점불일치, 항로불일치, 선박크기불일치 및 저유동성 베이시스위험으로 구분할 수 있는데 그 중 시점불일치 베이시스위험은 특정일 기준으로 지급되는 실물 선박의 용선료와 일정기간의 평균으로 정산되는 FFA의 정산가격과의 차이에 의해서 발생하는 것으로 헤징오류 원인 중 가장 큰 차이를 발생시키는 것이다. 이 연구에서는 성약일 기준 용선료를 15일 간격 이동평균 용선료로 변경한다는 대안을 제시하고 이의 차이와 운임선도거래 정산가격과의 차이를 도출하는 것을 역사적 시뮬레이션을 통하여 실증분석하였다. 연구결과 시점불일치 베이시스위험은 15일 이동평균을 적용함으로써 현저히 축소시킬 수 있는 것이 확인되었다. 이 연구는 용선료 지급기준 변경을 통해 베이시스위험을 축소하고 궁극적으로 운임선도거래를 활성화시킬 수 있는 가능성을 제시함으로써 해운실무에 유의미한 시사점을 제시한다. While the Forward Freight Agreement (FFA) has emerged as an effective hedging tool since early 1990, the basis risk and cash flow distortions have been addressed as obstacles to the active use of FFAs. This research analyses the basis risk of FFAs and provides a feasible suggestion to reduce it. Basis risk is divided into timing basis, route basis, size basis, and low liquidity basis. The timing basis is defined as the difference between the physical hire, fixed on the specific contract date and the FFA settlement price, calculated by averaging spot rates for a certain period. Timing basis is considered the worst in eroding the effectiveness of FFAs. This paper suggests a change of hire payment criterion from contract date to 15-day moving average, as a means of mitigating the basis risk, and analyzed the effectiveness through historical simulation. The result revealed that the change is effective in mitigating the timing basis. This study delivers a meaningful implication to shipping practice in that the change of hire payment criterion mitigates the basis risk and eventually activates the use of FFAs in the future.
유기용매의 처리에 따른 Bacillus subtilis IFO 12113 유래 Protopectinase의 회수
이승철,육현균,황용일 ( Seung Cheol Lee,Hyun Gyun Yuk,Yong Il Hwang ) 한국응용생명화학회 1997 Applied Biological Chemistry (Appl Biol Chem) Vol.40 No.2
To recover protopectinase (PPase) secreted from Bacillus subtilis IFO 12113, culture filtrate of the microorganism was treated with acetone, methanol, and ethanol, respectively. In the case of treatment with acetone at a ratio of 1 : 1 (culture filtrate : acetone, v/v), PPase was purified 1.7-fold with 59.2% recovery. The recovery of PPase was increased by increasing the acetone concentration. PPase was purified 4-fold with 100% recovery when the culture filtrate was precipitated with methanol at a ratio of 1 : 2 (culture filtrate : methanol, v/v). However, recovery of PPase was decreased by increasing the methanol concentration. PPase was purified 13.5-fold resulting in 68% recovery by the addition of ethanol with the final ratio 1 : 1(culture filtrate : ethanol, v/v) to the supernatant, which was obtained after precipitation of the culture filtrate with ethanol at a ratio of 1 : 0.5. These results show that methanol treatment is better than other organic solvent treatments for the simple recovery of PPase, whereas fractionated treatment of ethanol can recover PPase with higher purification fold.
Contrast-Detail Phantom을 이용한 CR에서 Image Plate의 사용 횟수에 따른 Contrast-Detail Curve의 변화
이승철,박장흠,김재동,박창현,Lee, Seung-Cheol,Park, Jang-Heum,Kim, Jae-Dong,Park, Chang-Hyeon 대한디지털의료영상학회 2005 대한디지털의료영상학회논문지 Vol.7 No.1
Purpose : Image plate (IP) is substituted for film in computed radiography. This study is to investigate into a variation of contrast and detail by the number used of image plate in computed radiography. Materials and Methods : A Contrast-Detail(CD)-RAD 2.0 phantom(Nijmegen hospital, The Netherlands) was used for this study. The computed radiography(CR) CD-RAD phantom images were acquired at 40 kVp, 160 mA, 1.6 mAs, and small focus with the Shimadzu general radiography UD-150B-10 system and Fuji FCR 5000 image process system with speed of 200. The IP used including once, 5000 times, and 10000 times also was used. The numerical value of image quality figures (IQF) was produced by CD-RAD analyser(the program is installed in the directory), and then contrast-detail curve was drawn. Results : In this study, the value of IQF was 3.53 in IP used once, 3.40 in 5000 times, and 3.22 in 10000 times. Conclusions : There was a variation of contrast-detail curve by the number used of IP with contrast-detail phantom in computed radiography. Therefore, it is necessary that the IP with lower IQF and a shift of contrast-detail curve to the lower left part is used.