Rock Bolt의 길이 및 配置가 地下構造物의 支保效果에 미치는 影響

유희중,조기옥 호남대학교 산업기술연구소 1997 산업기술연구논문집 Vol.4 No.-

본 실험적 연구는 Rock Bolt의 길이와 배치간격이 지하 구조물의 지보효과에 미치는 영향을 고찰하기 위하여, 시공 중인 터널공사의 실물을 대상으로 실험을 수행하였다. 실험은 8개소의 장소를 선정하여 4종류로 모델화하였고, 각 모델은 암질이 유사한 2개소를 묶어 상호 비교할 수 있도록 하였으며, Rock Bolt의 길이와 간격을 동일 또는 상이하게 배치하여 각 모델별로 분석이 가능토록 하였다. 연구결과 Rock Bolt의 길이가 길어질수록 넓게 배치할 수 있었으나, 일정 수량 이상의 배치는 Bolt수량의 증가만큼 지보효과를 높일 수 없었다. 또한 같은 강도의 암질이라 할지라도, 절리의 방향과 위치에 따라 Rock Bolt의 Bolting 방향과 시공시기가 지보효과에 상당한 영향이 있는 것으로 판단되어, 앞으로 이 분야에 대한 연구가 있어야 할 것으로 사료된다. In this research, reinforcing fects of the length and the space of rock bolt on the underground structure was investigated through field test at the tunnelling work sites. In this test, 8 test sites were selected and modelized of 4 groups. Each group was consisted of 2 rock masses with equal quality to facilitate comparison of the reinforcing effects of length or space of the rock bolt. As a results, the length of rock bolt should be determined by the consideration of rock mass quality and tunnel width. The space of rock bolt could be increased as the length of rock bolt. The more rock bolts were installed, the more the tunnel was reinforced, the more the reinforcing effect of each rock bolt was diminished. Even if the strength of rock mass are equal, it was found that reinforcing effects are varied with the orientation and the installation time of rock bolts and with the orientation and the location of joints. So the continuous study on the rock bolting system with these variables is more desirable.

H-形鋼 斷面性向을 考廬한 트러스의 多目的 函數 퍼지最適化에 관한 硏究

유희중,조동영 호남대학교 산업기술연구소 1997 산업기술연구논문집 Vol.5 No.-

구조물의 최적설계문제에 퍼지이론을 이용한 구조물의 최적화는 최적화문제에 불확실성이 포함되어야 하므로 일반적인 구조물의 최적화에 비하여 최적화문제의 형성이 복잡하다. 또한 최적화문제가 형성되었다고 해도 서로 상충되는 여러개의 목적함수를 동시에 고려해서 최적화문제의 해를 구해야 하므로 최적화 과정이 단일목적함수를 고려한 구조물의 최적화에 비하여 매우 복잡하다. 따라서 본 연구에서는 다른 연구와 달리 구조물의 최적설계에 실제 생산되고 있는 H-형강의 단면 성향을 고려하였으며, 또한 구조물을 구성하는 재료의 특성치가 분명하지 않으므로 해서 설계에서 발생할 수 있는 불확실성을 포함한 트러스 구조물의 최적화를 시도하였다. 본 연구에서는 최적화를 효과적으로 수행하기 위하여 설계변수로 부재단면적을 취하고, 목적함수는 서로 상반되는 체적과 변위를 제1목적함수, 제3목적함수로 하였다. 제약조건은 퍼지량인 응력 제약조건을 고려한 최적화문제를 형성하여 허용방향법에 의한 다목적함수 퍼지 최적화기법으로 최적해를 구하였으며, 2부재, 7부재의 트러스 구조물에 적용한 결과, 본 연구의 알고리즘은 적용성, 타당성 및 효율성이 있다고 사료된다. The structural optimization using fuzzy theory to the optimum design of the structure should include uncertainties in the optimizing problem. Therefore, in this case the optimizing problems are structures. Also although the optimizing problems are made, they should be solved by simultaneously considering several objective functions that are individually different. So the process of this optimization is very complex, compared to that of the optimization considering a single objective function. Accordingly, thsi study distinctively considered the sectional properties of H shape steel actually being produced for the optimum design of the structure and tried the optimization of truss structures including uncertainties that can happen in design due to the ambiguity of the specific value composing one structure. In this study, to effectively execute the optimization, the section areas of member were taken as the design variables and the objective functions took volume and displacement being contrary to each other as the first objective function and the second one. As restraint conditions formed the optimizing problems considering stress restraint conditions, the optimum was obtained by the fuzzy optimization method of multiple-purpose function in allowable direction method. As a result of applying to truss structure of the 2 member and 7 member, the algorithm of this research was for the applicability, propriety and effciency.

재생골재 혼합율에 따른 콘크리트 압축강도 변화에 관한 연구

조동영,유희중 호남대학교 2003 호남대학교 학술논문집 Vol.24 No.2

적층고무 받침을 사용한 강상형교의 시공단계별 대기온도변화에 따른 Steel Box의 실제 온도에 관한 연구

조동영,유희중,임삼규 호남대학교 2003 호남대학교 학술논문집 Vol.24 No.2

용융염산화 반응기에서 기체체류량 및 기-액 흐름특성

조용준,양희철,은희철,유재형,김준형 한국화학공학회 2003 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.41 No.5

용융염산화는 혼성폐기물과 유해폐기물을 효과적으로 산화 및 분해할 수 있는 소각대체기술중 하나이다. 본 연구에서는 직경이 0.079 m이고 높이가 0.653 m인 용융염산화 반응기에서 기체체류량 및 기-액 흐름특성에 대한 연구를 수행하였다. 액상으로 용융탄산나트륨을 기상으로 건조된 공기를 사용하였으며 기체유속(0.05-0.22 m/s)과 용융염온도(870-970℃) 변화가 기체체류량 및 기-액 흐름특성에 미치는 영향을 규명하였다. 기체체류량은 용융염 온도가 상승함에 따라 증가하였는데, 이는 용융염 온도의 증가로 인해 용융된 탄산나트륨의 점도와 표면장력이 감소하였기 때문이다. 실험에서 얻어진 기체체류량 데이터를 drift-flux 모델에 적용하여 용융염반응기 내의 흐름특성을 규명할 수 있었으며, 이를 통해 흐름영역에 따른 기체체류량을 정확하게 예측할 수 있었다. Molten salt oxidation is one of the most promising alternatives to incineration that can be used to efficiently destroy the organic components of mixed wastes and hazardous wastes. In this study, the gas holdup and gas-liquid flow characteristics are investigated in the molten salt oxidation reactor (0.076 m D×0.653 m H.). Effects of input air velocity (0.05-0.22m/s ) and molten salt temperature (870-970℃) on the gas holdup and flow characteristics have been studied. Molten carbonate as the liquid phase and air as the gas phase have been used in this study. The gas holdup increases with increasing molten salt temperature due to the decrease of viscosity and surface tension of molten carbonate. The experimentally obtained gas holdups in the molten salt reactor have been well described and characterized by means of drift-flux model. The gas holdups with variation of the flow regime have been well predicted.

보육시설 과학 특별활동 프로그램의 개발과 적용

조복희,곽혜경,한유미,양연숙,손경화 한국영유아보육학회 2003 한국영유아보육학 Vol.0 No.32

The purpose of this study was to develop early childhood science activities, which could be utilized as an extracurricular program in the day-care center. The program is based on the Constructivist theory(Piaget and Vygotsky) and the nation-wide survey data on the extracurricular programs and science activities in the day-care center. After the manuals for the program was monitored and corrected by the professionals, the application of each activities was empirically tested by the teachers in the day-care setting. The effects of the sample program(6 activities) were conducted using Tegano, Sawyers & Moran(1989)'s Scientific problem-solving scale and Lee(2001)'s Scientific attitude scale. Subject of thirty nine children were administered by the pre-test and post-test and experimental group participated the program for six weeks. The results showed that the program was effective for enhancement of scientific problem-solving ability and scientific attitude of young children in day-care setting.

상아질 형성 부전증에 대한 증례보고

김희진,위유민,박성규,홍성수,조태식,이상호 조선대학교 구강생물학연구소 2002 口腔生物學硏究 Vol.26 No.2

Dentinogenesis imperfecta is an inherited disorder of dentin formation, usually exhibiting an autosomal dominant mode of transmission. Type Ⅰdentinogenesis imperfects occurs in Patients afflicted with osteogenesis imperfecta. Type Ⅱdentinogenesis imperfecta is not associated with osteogenesis imperfects. Type Ⅲ dentinogenesis imperfecta (Brandywine type) occurs in a racial isolate area in the state of Maryland. Clinically, the color of teeth may range from a gray to brownish violet or yellowish brown with translucent or opalescent hue. The enamel often chips and fractures away, allowing speedy attrition of the remaining, poorly calcified. softer dentin. Roentgenographic features include pulpal obliteration, bulbous crowns and short and blunted roots. The cementum, periodontal membrane and the supporting bone appear normal

소득작물 전후작지 적응 극단기성 벼 ‘중모 1032’

손영보,이종희,조준현,이지윤,오성환,송유천,박동수,박노봉,김상열,여운상,남민희,권영업 忠北大學校 農業科學硏究所 2015 農業科學硏究 Vol.31 No.2

붓스트랩방법을 이용한 피로모형의 설계곡선 설정

서순근,조유희 한국품질경영학회 2002 품질경영학회지 Vol.30 No.4

The fatigue curve with estimated parameters represents the estimate of the median or mean life at a given applied stress. But, in order to assist a designer in making decisions regarding the fatigue failure mode, it is common practice to construct a design curve on the lower or safe side of data. In this study, to overcome the limitations(i.e., no runout, equal variance, and quality of the approximation, etc) of Shen, Wirsching, and Cashman's method which suggested the approximate design curve for nonlinear models using tolerance interval constructed by Owen's method, an algorithm to find design curves under the fatigue model using a parametric bootstrap method, is proposed and illustrated with multiple fatigue data sets.

피로곡선 모형의 통계적 분석 및 비교

서순근,조유희 한국품질경영학회 2003 품질경영학회지 Vol.31 No.2

The fatigue has been considered to the most important failure mode where optimal design or reliability prediction of the machinery in aircraft, atomic reactors, and structure systems, etc.. is required. When the statistical analysis of fatigue life data is performed, some difficulties are present because of the following facts : nonlinear relationship, heteroscedastic data, large scatter in the data, censored data (runouts), and existence of fatigue limit. To find the S-N curve models that characterize fatigue strength better, this research compares existing fatigue curve models developed recently in terms of the residual mean square and the estimate of fatigue limit, etc. for various fatigue data sets.