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        검색결과 442

        201.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, electric propulsion leisure boat with 9 meters length is designed and the performances are investigated by CFD analysis and model test. Maximum speed of the developed boat is 15knots(7.7 m/s) using 80Kw electric motor. Catamanan type hull form with slender body is adopted considering high Froude number and large deck area. Two kinds of hull forms are designed and the performances are compared in resistance point of view. Wave patterns are observed to make clear the relationship between resistance performance and wave characteristics. The results show that not only wave interaction due to shoulder waves but also stern waves have a strong influence on resistance performance and CFD analysis including free surface can give useful informations at initial ship design stage for high Froude number catamaran boat.
        4,000원
        202.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, a new designed propeller was applied on 24 ton class squid jigging vessel to reduce of fuel consumption. The selected squid jigging boat was under construction at the shipyard to determine the resistance of the hull through the model experiment. The propeller design was carried out by using the experimental data and ITTC procedures. Sea trials were performed by measuring the speed and the horsepower required by the condition of five power levels of engine load, namely 70%, 80%, 90%, MCR and maximum engine power. The speed and delivered horse power were compared between the conventional propeller and the new design propeller. Delivered horse power by installing the new propeller takes 90% engine load at start-up conducted by decreased 9.06%. The measuring speed is increased up to the 0.6 knots in the low-speed range to high range. This study showed that only the design and installation of a new propeller can improve the propulsion efficiency of the boats; furthermore, reduce fuel costs can be achieved at the same time by improving the increased cruising speed.
        4,000원
        204.
        2016.11 구독 인증기관 무료, 개인회원 유료
        Lentinula edodes, shiitake, is a very important non-timber forest product that has been consumed more than 50,000 tons every year in Republic of Korea. However, the rapid increase of imported shiitake media from China has eroded domestic goods’ competitiveness. The domestic shiitake industry has faced this situation and has exerted great efforts to localizing shiitake spawn while encouraging the growers to utilize the domestic shiiake spawn. To address such a challenge, the “Golden Seed Project” was designed, with an objective to expand the market share of domestic spawn and to increase the exports of the domestic spawn within the period of 2013 to 2021. Under the project, two projects and five commissioned sub-projects have been conducted up to now, making some outcomes. Protections of two new varieties (Sanmaru 2-ho and Sanbaekhyang) of shiitake, whose cultivation periods were shortened up to 20 days compared to the existing ones, have been applied. Also, there have been three cases of technology transfers of new varieties to private enterprises, all of which contributed to disseminating domestic spawn. Besides, the research team has held public fairs and presentations of new shiitake varieties in a regular basis, while operating a total of 24 test beds consisting of log cultivation and sawdust bag cultivation. Meanwhile, other research projects have been done to identify fruit-body ingredients and the properties of molecular markers of mating types and to monitor diseases and pests. The second stage of “Golden Seed Project” aims to increase the share of domestic spawn in the domestic market, up to more than 70%.
        4,800원
        212.
        2016.10 구독 인증기관·개인회원 무료
        해양사고의 건수는 연평균 1,700회 이상이며 기관손상사고는 전체의 31.5%이다. 기관손상사고 중에서도 추진축계와 관련된 사고는 과다한 부하에 기인한 베어링의 마멸로 발생하며 정상운항에 큰 피해를 줄 수 있는 매우 중요한 요인이다. 이 연구에서는 선박의 추진축계 베어링 발열 사고를 사례분석을 통해 고찰하였다. 그 결과 축계정렬불량이 주 원인으로 분석되었고 이에 대한 주기적인 점검으로 사고를 줄일 수 있을 것으로 판단된다.
        213.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Agriculture, Forestry and Fisheries Research Council within the Ministry of Agriculture, Forestry and Fisheries looks over the Agriculture, Forestry, and Fisheries Research and Development Project. Every five years, it revises the Agriculture, Forestry and Fisheries Research Basic Plan. Based on the information above, the following suggestions are made to implement domestic research projects. First, the strategic planning and promotion of research and development projects are needed to achieve the goals of the country and agricultural policy. Second, it is necessary to break up and diversify research assignments so that the project implementation reflects the trend of the time. Third, there is a need to develop a research partnership that strengthens cooperation among industry, academia, government, and research institutes to utilize technology seeds from fields other than agriculture. Fourth, it is necessary to improve field demonstration research projects where central and local research institutes, universities, private companies, agricultural cooperation, and farmers can participate. Fifth, follow-ups should be conducted at the end of research to advance research implementation systems. Finally, there is a need to build a new dissemination system which includes research results and policy.
        4,000원
        216.
        2016.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 고체추진기관의 2차원 축대칭 FSI 해석에서 CSS 및 ISS 기법의 수치 안정성을 고찰하였다. 이를 위하여 CSS 및 ISS 기법을 2차원 축대칭 FSI 수치해석 알고리즘에 구현한 프로그램을 작성하고, 이를 ACM 및 BCM 고체추진기관의 복합거동 해석에 사용하였다. 해석 결과들을 비교 분석하여 ISS 기법이 고체추진기관 FSI 해석의 수치 안정성 개선에 효과적인지 검토하였다. 연구결과, ISS 기법을 적용한 FSI 해석은 시스템 시간간격이 작아질수록 수치적 수렴성을 보이며, CSS 기법과 다르게 시간이 진행되어도 수치해의 진동이 발산하지 않는 것을 확인할 수 있었다. 이를 통하여 ISS 기법을 사용하면 ACM 및 BCM의 FSI 해석에 CSS 기법을 이용할 시 나타나는 수치 불안정성을 개선할 수 있음을 확인하였다.
        4,000원
        220.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        에너지자원의 안정적인 확보는 국가발전을 위한 가장 중요한 요소 중 하나이다. 본 연구는 혁신시스템 관점에서 우리나라의 에너지관련 정책결정시스템을 분석하고 그 문제점을 도출하였다. 혁신시스템의 구성요소 중 혁신주체 측면에서는 에너지의 안정적인 수송을 위한 전략적인 강화방안이 미흡하다는 한계를 가지고 있었으며, 연계측면에서는 국방영역을 제외한 혁신주체들 간의 연계는 비교적 양호하였으나 안보적 관점에서 중요한 역할을 담당하는 국방영역과 타 혁신주체들 간의 연계는 미흡한 것으로 분석되었다. 하부구조 측면에서는 에너지안보 관점에서 국방영역의 하부구조인 전력건설 논의가 미흡한 것으로 나타났으며, 마지막으로 제도적 측면에서는 에너지안보에 관한 국방영역의 역할에 대한 제도적 정립이 미흡하여 향후 국가 에너지안보와 관련된 거버넌스에서 국방영역의 참여가 제도적으로 명시될 필요가 있는 것으로 분석되었다.
        4,000원