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        검색결과 24

        2.
        2024.04 구독 인증기관·개인회원 무료
        본 연구는 도로 노면의 결빙을 방지하기 위해 열적 특성을 갖는 콘크리트를 개발했습니다. 팽창 점 토에 상변화 물질(PCM)을 함침 시키고, 고열 전도성 에폭시와 실리카 흄으로 이중코팅을 하여 PCM 물질의 유출 방지, 골재의 부착성 개선, 열적 성능 개선을 하였으며 이를 DSC를 통해 열적 성능 평가 를 진행하여 확인했습니다. 또한 상변화 물질과 경량골재의 사용으로 인한 강도 감소 개선을 위한 CNT 혼합으로 강도 감소를 25% 개선하였습니다.
        4.
        2023.05 구독 인증기관·개인회원 무료
        The configuration management system was implemented on the basis of a document management system that secured stable understanding, scalability, document security, and convenience in small modular reactor. To reduce the cost and risk of errors, configuration management is implemented to maintain a balance between design requirements, physical configuration, facility configuration information. In the initial stages, configuration change review procedures was developed with the main purpose of change management such as classification system management, configuration control committee management, configuration change review preparation, configuration control committee operation, followup measures, current status and tracking management. The preparation of the configuration change review consisted of preparation, distribution approval, designation of reviewers, review, collection of review opinions, and preparation of resolution results. In the operation of the configuration control committee, it was conducted by designating review members, reviewing members, collecting operation, and approval them. The next step is to supplement and develop the requirements of IEEE Std 828-2012, such as configuration management planning, configuration management control, configuration identification, configuration change control, configuration status monitoring, configuration audit, interface management, and release management. Through this, issue raising, action management, and baseline management will be implemented.
        8.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims at developing the paraglider with the enhanced function and safety of flight by performing the simulation and test of flight with two slots at each wing tip of canopy. When the distributions of velocity and shear stress at wall around the canopy were compared, the canopy with slots showed the distribution of less velocity and shear stress at wall significantly than the canopy without slots by confirming the safety of the paraglider. Series of simulation were conducted to achieve the optimal shape of slots by applying various sizes and positions of the slots, resulting nine cases with the better outcome on which flight tests were based. The flight test results in this study confirmed that canopy with slots showed the improved flight function by increasing the maximum velocity, decreasing the minimum velocity, delaying the stall timing significantly and consequently improving the safety of the paraglider. Based on the simulation and flight tests, three cases with the best outcome have been selected for merchandising strategies.
        4,000원
        9.
        2013.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        미즈나미 지하처분연구시설 프로젝트는 일본원자력연구개발기구가 결정질암 내의 심부 지하 환경에 관해 종 합적으로 연구하는 프로젝트이다. 미즈나미 프로젝트는 3개의 중첩되는 단계로 구성된다: 지표기반 조사단계 (단계 1), 건설단계 (단계 2), 운영단계 (단계 3)의 총 20년. 미즈나미 프로젝트의 1단계에서 3단계까지의 전체 목표는 1) 심부지질환경을 조사, 분석, 평가하기 위한 기술 정립, 2) 심부 지하 활용을 위한 일련의 공학적 기 술 개발이다. 전체 목표 1을 달성하기 위하여, 1단계 목표를 굴착 전에 지질환경을 모사하고 굴착거동을 예측 하는 모든 지표기반 조사결과로부터 지질환경 모델을 구축하는 것으로 설정하였다. 전체 목표 2를 달성하기 위하여, 2단계 목표는 지하시설을 위한 상세 설계 개념과 건설 계획을 수립하는 것으로 설정하였다. 본 논문은 결정질암내 지하수의 수리지화학적 특성을 조사하고 평가하기 위한 지질통합적 방법을 소개한다.
        5,100원
        10.
        2012.11 구독 인증기관 무료, 개인회원 유료
        최근 현대사회는 자동차, 철도 및 항공 등 대형 복합 시스템의 체계 속에서 지내고 있으며, 고장 및 사고로 인한 시스템의 안전 설계에 대한 고려와 안전에 대한 인식이 증가하고 있다. 따라서 기존의 시스템공학 프로세스에서 다루는 시스템 설계에 대한 단계별 안전 활동의 강화의 필요성 역시 강조되고 있다. 그 중에서도 시스템 설계의 최종 활동에 해당하는 검증 단계 활동이 제대로 수행되어야만 초기에 의도한 시스템 설계의 안전도 향상을 바라볼 수 있을 것이다. 본 논문에서는 안전 활동을 고려한 시 스템공학 프로세스의 검증 단계의 개선사항 도출과 모델링을 통해 안전중시 시스템인 철도 차량 운전실 시스템을 대상으로 적용 및 조정 구축에 대한 내용을 기술하고 있 다. 본 연구의 결과를 토대로 향후 품질 향상 및 비용 절감과 데이터의 관리
        4,500원
        11.
        2011.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        중저준위 방사성폐기물 처분장의 안전성 평가를 위하여 지하 사일로와 그 주변의 굴착손상영역 (EDZ) 및 단열암반을 고려한 지하수유동해석과 핵종이동해석의 통합모델을 개발하였다. 사일로를 다중방벽개념으로 고려하여 사일로를 구성하는 3개의 특성지역 (waste, buffer, concrete)으로 구분하여 해석하였고, EDZ는 사 일로 주변과 건설운영 터널 주변의 손상영역을 고려하였다. 단열암반의 불균일성은 분리단열 (discrete fractures)로 부터 해석된 불균일한 지하수 유속계로 도출하였고, 그 결과를 핵종의 이동경로를 모사하는데 사 용하였다. 현 모델은 핵종누출에 따른 사일로 배치의 최적화와 안전성의 정량화를 도출하는데 사용가능하다
        4,000원
        13.
        2003.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alpha-SiAlON ceramics having various compositions and modifying cations were investigated with respect to their phase stability, transformation kinetics. and resulting microstructures. Each composition was heat treated at 150 for 1h and measured the -SiAlON transformation. The phase-boundary composition in the single-phase -SiAlON region showed sluggish transformation from - to -SiAlON compared to the phase-center composition in the diagram. Using the different rare earth modifying cations, dependence of transformation kinetics on the phase stability in a fixed composition was also explained. By changing size of the stable u-phase region with exchanging cations, systematic change in transformation was observed. Transformation rate of -SiAlON at low temperature has an important role on controlling the final microstructure. Less transformation gives more chances to develop elongated grain in the microstructure.
        4,000원
        14.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Liquid-phase methanol synthesis via methyl formate using coal-derived syngas was carried out in a bench-scale(diameter 173 mm and dispersion height 1200 mm) slurry bubble column reactor(SBCR) Under the condition of 180˚. 61 atm, 30 L/min, H2/CO=2 and a slurry mixture of 2 kg of copper chromite and 0.5 kg of KOCH3 suspended in 14 L of methanol, the per pass conversions of syngas is 6 %, maximum concentration of methyl formate 3.088 mol% and maximum synthesis, rate of methanol 0.8 gmole/kg · hr. It is a significant evidence that copper chromite powder as heterogeneous catalyst didn't active for the hydrogenolysis of methyl formate to methanol, resulting copper chromite powder was not efficiently suspended in a slurry mixture. To enhance the hydrogenolysis of methyl formate in liquid-phase methanol synthesis process, the designed SBCR have need to use the higher specific gravity solvent and/or decrease the catalyst particle size.
        4,000원
        15.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Pb(In1/2Nb1/2)O3 (PIN)세라믹스에서 Pb+2이온 대신에 Ca+2, Sr+2, Ba+2 이온을 부분적으로 치환하여 상합성 과정 및 유전특성을 조사하였다. 페로브스카이트 PIN을 얻기위한 최적조건을 도출하기위하여 하소, 치환 이온의 종류 및 그량, 소결민돌, 유전특성의 관점에서 관찰하였다. 페로브로스카이트 PIN상을 합성하기 위해서는 Ba+2이온의 치환이 가장 효과적이었다.
        4,000원
        17.
        2020.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In order to avoid the high cost and high risk of demonstration mission of rendezvous-docking technology, missions using nanosatellites have recently been increasing. However, there are few successful mission cases due to many limitations of nanosatellites like small size, power limitation, and limited performances of sensor, thruster, and controller. To improve the probability of rendezvous-docking mission success using nanosatellite, a rendezvous-docking phase analysis tool for nanosatellites is developed. The tool serves to analyze the relative position and attitude control of the chaser satellite at the docking phase. In this tool, the Model Predictive Controller (MPC) is implemented as a controller, and Extended Kalman Filter (EKF) is adopted as a filter for noise filtering. To verify the performance and effectiveness of the developed tool for nanosatellites, simulation study was conducted. Consequently, we confirmed that this tool can be used for the analysis of relative position and attitude control for nanosatellites in the rendezvous-docking phase.
        18.
        2016.01 KCI 등재 서비스 종료(열람 제한)
        To investigate the impact of the number of runners developed from daughter plants during seedling on sapling growth and development during phase of first cluster, we examined four treatment groups that had 3–4, 5–6, 7–8, and 9–10 runners. As of June 5th, the group with 9–10 runners showed the highest number of saplings with more than 2 leaves, followed by groups with 7–8, 5–6, and 3–4 runners. Although observation on June 25th and July 15th showed a similar tendency for sapling numbers, no significant difference was detected between groups with 7–8 and 9–10 runners. The length of runners in the treated groups was similar to that in groups with 3–4 and 5–6 runners, with lengths of 49.4 mm and 48.0 mm, respectively, but runner length was significantly shorter in the group with 7–8 runners. Both the thickness and the weight of runners were highest in the group with 3–4 runners. The growth and development of daughter plants and root weight were similar between the groups with 3–4 and 5– 6 runners, whereas both values were lower in groups with 7–8 and 9-10 runners. While stem crown thickness values were 8.7 mm and 8.5 mm in groups with 3–4 and 5–6 runners, respectively, groups with 7–8 and 9–10 runners had thinner stems of 7.1 mm and 6.2 mm, respectively. The fresh weight of saplings decreased as the number of runners increased. From the phase first cluster, leaf area and fresh weight were remarkably low in groups with 7–8 and 9–10 runners. Taken together, these results can be used to increase the production of high-quality saplings by providing a foundation for studies to investigate the impact of the number of runners developed from daughter plants on growth and development during the seedling period and the phase first cluster.
        19.
        2013.12 KCI 등재 서비스 종료(열람 제한)
        The present study aims to provide an analytical framework for achieving aid and development effectiveness of agricultural cooperation with a demand-oriented perspective. This paper pays particular attention to categorize the stages of agricultural development of African recipients to identify demands for agricultural aid of the categorized groups. To do so, first of all, it establishes theoretical background to apply the demand-oriented concept and utilize the phase of agricultural development as an alternative for aid and development effectiveness. On the basis of the theoretical robustness, it conducts a series of analyses to categorize the African recipients by the development stages, incorporating factor analysis, cluster analysis and comparison between the present-future agricultural development levels. The findings propose analysis indicators for phase of agricultural development and clustered results including 18 countries of KAFACI members and priority countries in Africa. In addition to the practical application of the results, the methodological flow can be used as steps for sketching a future roadmap to construct the demand-oriented ODA(Official Development Assistance) plan. This paper also offers implications regarding ODA strategy of Korea in response to the phase of agricultural development and the aid demands.
        20.
        2013.04 서비스 종료(열람 제한)
        This study aims to investigate basic requirements for adopting the Building Information Modeling(BIM) technology to CO2 monitoring system of building maintenance. This study is progressed to emphasis to utilize BIM building information to estimate amass of CO2 on the maintenance stage. The main purpose of this monitoring technology suggest the effective use of information which enable to efficient evaluation technology.
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