이음면 이격이 확장형 단부판 이음부 성능에 미치는 영향에 대한 실험적 연구

김철환,이명재,김희동,김사빈,Kim, Cheol Hwan,Lee, Myung Jae,Kim, Hee Dong,Kim, Sa Bin 한국강구조학회 2016 韓國鋼構造學會 論文集 Vol.28 No.6

This study is experimental research for the effect of gap at the end plate on the performance of extended end-plate type splice. For this research, simple beam type specimens by using extended end-plate type splice are planned. Main variables are the initial gap between end-plates, the installation of finger shim plate before the installation of high tension bolts, the final gap between end-plates, and the installation of finger shim plate after the installation of high tension bolts. The static loading tests results show that the maximum bending strength of splice is not dependent on the gap, but the vertical displacement, initial stiffness and elastic stiffness are affected by the gap. In addition to that, the possibility of brittle fracture is increased when the torque of high tension bolt is used to control the gap. Thus, careful consideration is needed in this case. 두본 연구는 실험적인 방법을 통하여 단부판 이음부의 이음면에서 초기 오차로 발생하는 이격이 이음부의 내력 및 거동에 미치는 영향을 평가한 연구이다. 이를 위하여 총 5가지의 단순보형 실험체를 확장형 단부판 이음부를 이용 계획하였고 주요 변수로는 이음면 초기 이격(gap) 여부, 고력볼트 채결 전 끼움판(finger shim plate) 설치 유무, 고력볼트 체결 후 이음면 이격, 고력볼트 채결 후 끼움판 삽입 여부를 적용하였다. 정적가력실험 결과 이음판의 이격은 이음부의 최대휨강도에 미치는 영향은 제한적이나 수직변형과 초기 및 탄성강성에는 영향을 미치는 것으로 나타났으며, 이격을 제어하기 위해 고력볼트 장력을 이용할 경우 고력볼트의 취성파괴 우려도 있는 것으로 나타나서 이들에 대한 충분한 고려가 필요할 것으로 판단된다.

민.군겸용기술사업 활성화 방안 연구

김철환,최은호,허환,Kim, Chul-Whan,Choi, Eun-Ho,Heo, Whan 한국국방경영분석학회 2006 한국국방경영분석학회지 Vol.32 No.1

This study aims to propose alternative suggestions for practical and efficient implementation of Dual Use Technology Programs(CUTP) in Korea which can strengthen both national security and industrial competitiveness. DUTP of Korea has suffered from inefficiency and inactivity. This study analyzes the Inefficiency and negative factors of DUTP of Korea by examining the previous cases of the advanced countries. It also examines individual problems of DUTP carefully and attempts to derive alternative solutions to improve the current situation. First, a global government plan should be made considering Korea's weapon system and Korea's industrial characteristics. Second, DUTP should begin to develop core technology in connection with technology level evaluation and technology exchange project should establish a comprehensive information network system which links any civilian and military technology data. Third, technology transfer project should be promoted by utilizing cyber technology exchange market and military defense venture center. Fourth, standardization project should be expanded by establishing a national standard information system. 국가안보와 산업경쟁력 강화를 동시에 향상시킬 수 있는 민 군겸용기술사업은 효율성 부족과 추진실적 저조로 새로운 개선방안이 필요한 시점이다. 본 연구에서는 그 원인을 선진국과 비교 분석하여 각 사업별 문제점 및 개선점을 도출하고, 민군겸용기술사업의 활성화를 위한 세부 사업별 대안을 제시하고자 한다. 먼저, 우리나라의 무기체계와 산업구조의 특성을 고려한 범정부차원의 정책을 수립하고 활성화 프로그램을 계획해야 한다. 이를 근간으로, 겸용기술개발은 기술수준 조사와 연계하여 필요 핵심기술을 선 개발하고, 기술교류 사업은 민간 및 국방 분야의 모든 기술자료를 연계할 수 있는 통합정보 시스템을 구축해야 한다. 또한 사이버 기술거래시장과 국방벤처센터를 활용하여 기술이전사업을 촉진하고, '국가 규격 및 표준정보체계'를 조속히 구축하여 규격통일화 사업을 확대해 나가야 한다.

전외측대퇴유리피판 (Anterolateral Thigh Free Flap)을 이용한 구강안면부 결손의 재건

김철환,방대연,황승연,Kim, Chul-Hwan,Bhang, Dae-Yeon,Hwang, Seung-Yeon 대한악안면성형재건외과학회 2009 Maxillofacial Plastic Reconstructive Surgery Vol.31 No.6

Recently, the anterolateral thigh(ALT) flap, based on the septocutaneous vessels or musculocutaneous perforators from the descending branch of the lateral circumflex femoral artery has gained popularity in head and neck soft-tissue reconstruction. It has some advantages in free-flap surgery with respect to the radial forearm free flap, such as low donor site morbidity, availability of different tissues with large amounts of skin, adaptability as a sensate or flow-through flap (with the possibility of harvesting a long pedicle with a suitable vessel diameter). Moreover, the thickness of the flap is adjustable until the subdermal fat level, allowing it to be used as a thin or ultrathin flap. This clinical cases are ALT free flap reconstructions without functional impairment of the donor limbs (transitory and permanent) based on anastomosis with superficial temporal arteries and veins in patient of huge resection defect on face, lip and tongue.

미국의 무기체계 획득과정과 정책(1)

김철환,Kim, Cheol-Hwan 한국방위산업진흥회 1993 國防과 技術 Vol.- No.175

요즈음 논란이 일고있는 율곡사업등으로 해서 국방부나 각 군에서 혼란을 겪고 있는 "무기체계 획득과정 쇄신"에 도움이 되었으면 해서 미국의 무기체계 획득과정과 정책을 소개합니다 이번 호에 게재된 내용과, 93/10월호에는 –의사결정 지원체계 및 검토과정 –회기득사업요약서/사업계획서 –획득 전문화 제도(DAWIA) –무기체계 획득 및 군수지원 전산화(CALS) –획득정책 발전방향 순으로 계속해서 연재됩니다

구강암 수술 및 재건 환자에서의 C-Reactive Protein 수치의 변화

김철환,황승연,Kim, Chul-Hwan,Hwang, Seung-Yeon 대한악안면성형재건외과학회 2010 Maxillofacial Plastic Reconstructive Surgery Vol.32 No.5

Purpose: The aim of this study is that we evaluate the change of the White Blood Cell(WBC) count, Absolute Neutrophil Count (ANC), Erythrocyte Sedimentation Rate (ESR) and C-reactive Protein (CRP) values, and try to make standardization for postoperative sequels before and after the oral cancer resection and reconstructive surgery. Materials and Methods: The study was comprised of 34 patients (male 15, female 19) who were diagnosed as an oral cancer and had performed ablation and reconstructive surgery at Dankook university dental hos-pital. Each blood specimen was collected from patients and estimated WBC count, Neutrophil count, ESR, CRP on first, third, fifth, seventh day efore and after surgery and analyzing inter relationship between each value. Classifying Group I (resection with reconstructive surgery patients) and Group II (resection without reconstructive surgery patients). Also classifying group A (below 4 hours of operation time), Group B (4 to 8 hours of operation time), Group C (above 8 hours of operation time), each group was analyzed and compared. The Following results were induced. Results: (1) In coefficient of correlation, the CRP and WBC has highest value except WBC count and Neutrophil count. (2) There was no significant difference any lapse in the progress between Group I and II of WBC count, Neutrophil count, but the CRP shows statistically higher level in group I than group II at immediate postoperative day, and 1 to 5 days after surgery. (3) There is no significant difference any lapse in the progress between Group A, B, C of WBC count, Neutrophil count, but CRP shows statistically significant difference in 1 day, 3 days after surgery Conclusion: It should be suggested that, determination of CRP is most valuable parameter for postopera-tive management and determination of postoperative clinical changes than other parameter such as WBC count, neutrophil count, and ESR values in oral cancer patient after resection and reconstructive surgery, based on the results of this study.

Rotation-Up 공법에 의한 킬 트러스 대공간 구조물의 Erection 실험에 관한 연구

김철환,채원탁,백기열,정환목,Kim, Cheol-Hwan,Chae, Won-Tak,Baek, Ki-Youl,Jung, Hwan-Mok 한국공간구조학회 2013 한국공간구조학회지 Vol.13 No.2

There are a number of construction methods to build spatial structures such as erection method, Element method, Block method, Sliding method, Lift-up method and Push-up method. These methods are uneconomical and low accuracy, and require long construction duration because of a need of a scaffold or a tower crane to build spatial roof frame. In this study, the construction method to erect a truss structure was proposed as an economical and easy installation method. The proposed method has end hinges of keel truss and winches with horizontal cable. This method makes safe and accurate production and reduces construction duration because trusses are built on the floor or supporter. The goal of this study is to verify the validity of construction method by building scale model using the proposed method.

RC-S 복합보의 역학적 특성에 관한 실험적 연구

김철환,채원탁,Kim, Cheol Hwan,Chae, Won Tak 한국강구조학회 2002 韓國鋼構造學會 論文集 Vol.10 No.3

본 연구에서는 단부 철근콘크리트구조와 중앙부 철골구조로 이루어진 복합구조 보를 대상으로 내력 및 강성, 변형능력을 평가하기 위해 반복재하 실험을 행하였다. 주된 실험변수는 철근콘크리트와 철골보의 이종구조 이음부부의 응력전달을 위해 철골보에 접합되는 철근의 개수와 단부 콘크리트를 구속하여 강성을 상승시킬 목적으로 설치되는 부착판의 설치유무이다. 실험결과 모든 실험체가 방추형의 이력 거동을 나타내며 안정된 거동을 하였으며, 내력에 있어서는 부착판 설치 실험체의 경우가 기본형 실험체 보다 높게 나타났다. 또한, 강성에 있어서도 단부에 부착판을 설치한 실험체가 설치하지 않은 실험체에 비하여 보다 높게 나타났으며, 모든 실험체가 최대 내력시의 부재각이 0.03rad. 이상의 변형능력을 나타내고 있다. The beam of composite structure composed of the RC structure in the end part and steel structure in the central palt were investigated during cyclic loading, in order to evaluate strength, stiffness, and deformational capacity. The parameters used in this study include the amount of reinforced steel bar between the steel beam and RC structure and the existence of the sticking plate. Test results showed that all specimens had stabilized hysteresis loops. Likewise, the specimens with sticking plate had higher load-carrying capacity compared with the one without it. In addition, the stiffness of the composite structure was higher than the steel structure. All specimens also showed good rotational capacity.

Strain-induced Local Transport Properties in Epitaxial Pr0.7Ca0.3MnO3 Thin Films

김철환,Y. H. Jang,H. B. Moon,J. W. Kim,조진형 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.2

Pr0.7Ca0.3MnO3 (PCMO) thin films have been deposited on SrTiO3 (STO) substrates by using a pulsed laser deposition (PLD) method. By changing the in-situ annealing condition after the film deposition, we were able to prepare two different sets of films, where coexistence of both strained and relaxed structures was obtained using a synchrotron X-ray diffraction. We observe that the density of the strained structure depended on the cooling condition, as observed from the mesh scan of HL reciprocal lattice. In addition, structural characterizations of the films were carried out, and the local transport properties are discussed in terms of the strain-induced misfit at the grain boundary.

EVMS를 이용한 프로젝트 관리효율화

김철환,Kim, Cheol-Hwan 한국시스템엔지니어링협회 2005 시스템엔지니어링워크숍 Vol.6 No.-

CALS 구현 정책 방향

김철환,Kim, Cheol-Hwan 한국정보통신집흥협회 1996 정보화사회 Vol.103 No.-

CALS 추진의 주요 목표는 수동적이고, 서류중심인 정보를 국제 공통표준으로 디지털화시켜 통합적이고 자동화된 기술정보 공유 및 전송과정의 전환이며, 이와 같이 자동화되고 통합된 모습은 통합 데이터베이스(IDB)가 될 것이다. 이러한 CALS추진에 대한 구조적인 접근은 하부구조 현대화, 업무과정 혁신, 디지털 자료 획득, 그리고 기업통합으로 나타낼 수 있다. CALS 전략의 실행은 산업활동의 전 순기를 통하여 크게 하부구조 현대화, 업무과정 혁신, 디지털자료획득, 기업통합 등 4가지 요소들을 설명함으로써 가능하다.