운동에너지 탄과 적재포탄에 따른 전투시스템 내부에서의 순간화재발생에 대한 전산해석

이승철,전우철,이해평,이헌주,Lee, Seung-Chul,Jeon, Woo-Chul,Lee, Hae-Pyeong,Lee, Heon-Joo 한국군사과학기술학회 2013 한국군사과학기술학회지 Vol.16 No.6

In this paper, numerical analysis was performed about whether the flash fire of loaded shells breaks out in the virtual combat vehicle according to sorts of the kinetic energy ammunition as the preceding research for vulnerability analysis inside the combat system by an external threaty ammunition. In this simulation, Autodyn program was used and the Lee-Tarver ignition and growth model was used to determine the flash fire outbreak. In this study, the kinetic energy ammunition was set of type A and type B in two kinds and the loaded shells was set of COMPB, TNT, PBX9404 and ANB. As a result, TNT and PBX9404 have much higher flash fire probability than COMPB in high explosive, ANB has very low flash fire probability.

철도터널 내 화재 시 대피환경 확보를 위한 임계속도 산정식의 유효성 평가

이승철,이재헌,이승호,Lee, Seung-Chul,Lee, Jae-Heon,Lee, Seung-Ho 한국터널지하공간학회 2004 터널기술 Vol.6 No.1

본 연구에서는 3차원 전산유체역학 기법을 이용하여 열차터널 내 10MW급 화재발생 시, 대피환경에 대한 1차원 임계속도의 유효성을 평가하였다. 또한 터널의 입구속도가 1m/s, 2m/s (임계속도) 그리고 3m/s일 때의 터널 내 기류분포, 온도분포, 가시거리분포 및 오염물질분포가 대피환경에 미치는 영향을 각각 검토하였다. 그 결과, 세 가지 경우모두, 승객의 안전한 대피환경을 충분하게 제공하지 못할 것으로 예상되어 승객들은 유동방향 하류로 대피하여야 한다. 그러나 3m/s 입구속도의 경우는 1m/s, 2m/s의 경우 보다 승객의 대피환경에 있어서 좀 더 나은 결과를 보인다. 따라서 터널의 방재시스템의 설계 시, 안전한 대피환경을 확보하기 위해서는 임계속도보다 큰 입구속도의 시용이 요구된다. The effectiveness of one dimensional critical velocity method for evacuation environment at 10MW fire size in a railroad tunnel have been investigated in this paper by three dimensional CFD method. It was performed to evaluate the evacuation environment in terms of temperature distribution, visible distance distribution and CO concentration at some tunnel inlet velocity, 1m/s, 2m/s (near critical velocity), and 3m/s. At all inlet velocity, passenger should give away downward the flow direction because the inlet velocity can not afford to sufficient evacuation environment for passengers. In case of 3m/s inlet velocity, however, the evacuation environment for passengers is better than the other cases. To provide more safe evacuation environment on fire situation, tunnel inlet velocity should be larger than critical velocity.

초음파 밀링 공정을 이용한 텅스텐 중합금 나노복합분말의 제조

이승철,이창우,정성수,차범하,이재성,Lee, Seung-Chul,Lee, Chang-Woo,Jung, Sung-Soo,Cha, Berm-Ha,Lee, Jai-Sung 한국분말야금학회 2007 한국분말재료학회지 (KPMI) Vol.14 No.2

Ultrasonic-milling of metal oxide nanopowders for the preparation of tungsten heavy alloys was investigated. Milling time was selected as a major process variable. XRD results of metal oxide nanopowders ultrasonic-milled for 50 h and 100 h showed that agglomerate size reduced with increasing milling time and there was no evidence of contamination or change of composition by impurities. It was found that nanocomposite powders reduced at $800^{\circ}C$ in a hydrogen atmosphere showed a chemical composition of 93.1W-4.9Ni-2.0Fe from EDS analysis. Hardness of sintered part using 50 h and 100 h powder samples was 399 Hv and 463 Hv, respectively, which is higher than the that of commercial products (330-340 Hv).

운동에너지 탄에 따른 전투시스템 내의 순간화재발생에 대한 해석적 연구

이승철(Lee Seung-Chul),전우철(Jeon Woo-Chul),이해평(Lee Hae-Pyeong),이헌주(Lee Heon-Joo),이창현(Lee Chang-Hyun) 제어로봇시스템학회 2012 제어로봇시스템학회 합동학술대회 논문집 Vol.2012 No.7

본 연구는 외부 위협탄에 의한 전투시스템의 취약성을 분석하기 위한 선행연구로써, 운동에너지 탄의 종류에 따른 가상의 전투차량 내부에 적재포탄에서 순간화재발생 여부에 대한 전산해석을 수행하였다. 본 해석은 Autodyn 프로그램을 사용하였으며 순간화재발생을 판단하기 위해 Lee-Tarver ignition and growth model을 이용하였다. 본 계산에서 운동에너지 탄은 type A와 type B 두 가지로 설정하였고, 고폭탄은 COMPB, TNT 및 PBX9404를 설정하였다. 전산해석 결과, 고폭탄의 재질이 TNT와 PBX9404가 COMPB 재질보다 순간화재발생 확률이 상당히 높음을 알 수 있고 type B의 운동에너지 탄이 type A 보다 순간화재발생 확률이 다소 높음을 알 수 있었다.

악성 림프종 환자에서 발생한 다형홍반

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.

디지털 비디오 부호화에서의 고속 움직임 추정을 위한 저복잡도 알고리즘

이승철,김민기,정제창,Lee, Seung-Chul,Kim, Min-Ki,Jeong, Je-Chang 한국통신학회 2006 韓國通信學會論文誌 Vol.31 No.12C

In video standards such as MPEG-1/2/4 and H.264/AVC, motion estimation / compensation(ME/MC) process causes the most encoding complexity of video encoder. The full search method, which is used in general video codecs, exhausts much encoding time because it compares current macroblock with those at all positions within search window for searching a matched block. For the alleviation of this problem, the fast search methods such as TSS, NTSS, DS and HEXBS are exploited at first. Thereafter, DS based MVFAST, PMVFAST, MAS and FAME, which utilize temporal or spacial correlation characteristics of motion vectors, are developed. But there remain the problems of image quality degradation and algorithm complexity increase. In this thesis, the proposed algorithm maximizes search speed and minimizes the degradation of image quality by determining initial search point correctly and using simple one-dimension search patterns considering motion characteristics of each frame. MPEG-1/2/4, H.264/AVC와 같은 영상압축표준에서 사용되는 부호화 기술 중 움직임 추정 및 보상은 부호기의 복잡도에 가장 큰 영향을 끼친다. 영상 코덱에서 일반적으로 사용되는 전역탐색(Full Search) 방식은 최적의 정합블록을 찾기 위해 탐색 영역내의 모든 위치에서 SAD값을 비교하기 때문에 부호화 시간을 다량으로 소비하게 된다. 이런 문제를 개선하기 위해 초기에는 TSS, NTSS, DS, HEXBS 등 다양한 형태의 탐색 패턴을 활용한 고속 움직임 탐색 기법들이 개발되었고, 이후에는 움직임 벡터의 시 공간적 상관도를 이용한 DS기반의 MVFAST, PMVFAST, MAS, FAME 등이 개발되었다. 하지만 부정확한 움직임 벡터 탐색으로 인해 화질이 열화되는 문제와 알고리즘의 복잡도가 높아지는 문제는 여전히 해결해야 할 과제로 남아있다. 본 논문에서는 움직임 벡터 탐색시작점을 보다 정확히 결정하고, 각 프레임들의 움직임 특성을 고려한 단순화된 일차원 탐색 패턴들을 사용하여 탐색속도를 극대화하고 화질열화를 최소화시키는 알고리즘을 제안한다.

회원작품 - 큰지붕 닭갈비

이승철,Lee, Seung chul 대한건축사협회 2020 建築士 Vol.610 No.-

긴장재배치에 따른 PT 이방향 슬래브의 거동에 대한 해석적 연구

이승철,이영학,Lee. Seung-Chul,Lee. Young-Hak 한국방재학회 2011 한국방재학회논문집 Vol.11 No.6

본 논문에서는 이방향 포스트텐션 슬래브의 다양한 텐던의 배치에 따른 효과를 분석하기 위해서 유한요소법에 기반한 해석적 연구를 수행하였다. 등분포된 텐던의 배치에서부터 기둥의 중심선에 인접하게 배치되는 형태까지 연구범위를 설정하였고, 유한요소해석 상용 프로그램인 SAP에서 제공하는 휨-평면 요소를 사용하여 모델링을 하였다. 텐던 프로파일에 근거한 등가하중을 텐던 배치에 따라서 적용하였으며, 사용 하중 상태에서의 처짐과 순수 모멘트를 결정하기 위해 텐던에 대한 등가하중에 일반적인 중력하중이 부가되었다. 또한 해석 결과와 실험결과를 비교 분석하였다. In this paper, the FE analysis results are presented to evaluate the effects of various tendon layouts on the performance of post-tensioned concrete two-way slab systems. Various arrangements from uniform cable layouts to closely banded arrangements adjacent to column centerlines are considered. The slab is modeled using plate-bending elements in the software package SAP. Equivalent loads based on cable profiles are applied to the slab according to the tendon layout. Moment fields and deflected shapes are compared for the various tendon patterns. Gravity loads are applied in the usual way and superimposed on the results from the equivalent tendon loads to determine net moments and deflections at service load levels. In addition to a study of tendon layouts, the finite-element model is compared with experimental results.

산소과다가 임신에 미치는 영향에 관한 실험적 연구

이승철,조수헌,안형식,윤덕로,Lee, Seung-Chul,Cho, Soo-Hun,Ahn, Hyeong-Sik,Yun, Dork-Ro 대한예방의학회 1989 Journal of Preventive Medicine and Public Health Vol.22 No.1

The adverse effect of diving on the fetus may extend beyond n gestational process and outcome. Primiparous Sprague-Dawley rats were assigned to one of ten exposure schedules during gestatred $PO_2$ level, the following question about the effect of exposing a pregnant female to high partial pressure of inspired oxygen has been raised. 'What effect does an increased maternal $PIO_2$ have on fetal arterial $PO_2$ and therefore on possible fetal oxygen poisoning?' This study was carried out to observe the effects of maternal hyperoxia on gestational process and outcome. Primiparous Sprague-Dawley rats were assigned to one of ten exposure schedules during gestation. The treatment groups were subjected to either the high concentration of oxygen, or the high atmospheric pressure. On day 21 of gestation, laparotomy was performed to examine for number and distribution of implantations and live and resorbing embryos. Fetuses were weighed, and examined for gross malformations. Subsequently, they were fixed, measured in physical parameters, and examined for visceral anomalies. Minor visceral anomalies and anatomical variation was not found. Similarily, there were no significant differences when number of resorptions, mean fetal weights, pregnancy interruption rate were compared by analysis of variance. These results indicate that exposing rats to oxygen at increased atmospheric pressure doese not affect fetal health or survival.

에탄의 산화성 탈수소화를 위한 Boron 산화물이 첨가된 알루미나 촉매의 최적 제조조건

이승철,유의연,선우창신 ( Seung Chul Lee,Eui Yeon Yu,Chang Shin Sunwoo ) 한국화학공학회 1995 화학공학의이론과응용 Vol.1 No.2