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        검색결과 8

        2.
        2022.05 구독 인증기관·개인회원 무료
        In accordance with the Enforcement Decree of the Act on Physical Protection and Radiological Emergency, operators of Nuclear Power Plants (NPP)s must conduct full cyber security exercise once a year and partial exercise at least once every half year. Nuclear operators need to conduct exercise on systems with high attack attractiveness in order to respond to the unauthorized removal of nuclear or other radioactive material and sabotage of nuclear facilities. Nuclear facilities identify digital assets that perform SSEP (Safety, Security, and Emergency Preparedness) functions as CDA (Critical Digital Assets), and nuclear operators select exercise target systems from the CDA list and perform the exercise. However, digital assets that have an indirect impact (providing access, support, and protection) from cyber attacks are also identified as CDAs, and these CDAs are relatively less attractive to attack. Therefore, guidelines are needed to select the exercise target system in the case of unauthorized removal of nuclear or other radioactive material and sabotage response exercise. In the case of unauthorized removal of nuclear or other radioactive material, these situations cannot occur with cyber attacks and external factors such as terrorists must be taken into consideration. Therefore, it is necessary to identify the list of CDAs that terrorists can use for cyber attacks among CDAs located in the path of stealing and transporting nuclear material and conduct intensive exercise on these CDAs. A typical example is a security system that can delay detection when terrorists attack facilities. In the case of sabotage exercise, a safety-related system that causes an initiating event by a cyber attack or failure to mitigate an accident in a DBA (Design Basis Accident) situation should be selected as an exercise target. It is difficult for sabotage to occur through a single cyber attack because a nuclear facility has several safety concepts such as redundancy, diversity. Therefore, it can be considered to select an exercise target system under the premise of not only a cyber attack but also a physical attack. In the case of NPPs, it is assumed that LOOP (Loss of Offsite Power) has occurred, and CDA relationships to accident mitigation can be selected as an exercise target. Through exercise on the CDA, which is more associated with unauthorized removal of nuclear or other radioactive material and sabotage of nuclear facilities, it is expected to review the continuity plan and check systematic response capabilities in emergencies caused by cyber attacks.
        3.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 9종의 국화과 식물을 대상으로, 생리적 특성 및 생화학적 물질을 관찰함으로써 내건성식물 을 선발하였다. 크기와 생장이 균일한 식물체를 선발한 후, 단수처리를 통하여 건조 스트레스를 유발하 였다. 내건성식물 선발을 위해 엽록소함량, 엽록소함량, 상대수분함수량, 상대수분손실량, 프롤린, 환원 당을 단수일로부터 30일동안 관찰하였다. 식물 생존율은 단풍취, 벌개미취, 참취, 좁은잎구절초 순으로 높게 나타났고, 나머지 5종은 고사하였다. 내건성식물 선발을 위한 나머지 요인들은 높은 생존율을 얻 은 식물종을 기준으로 판단되었다. 그러나 엽록소함량은 단풍취, 단양쑥부쟁이, 벌개미취 순으로 높은 값을 보여, 단풍취와 벌개미취를 제외하고는 생존율과 연관성을 갖지 않는다고 판단되었다. 반면에 상 대수분함수량, 상대수분손실량, 프롤린, 환원당에서는 참취, 단풍취, 벌개미취 3종이 상대적으로 높은 내건성식물로 판단되었고, 생존율과도 비슷한 연관성을 나타내었다. 결론적으로 국화과 식물 9종 중 참 취, 단풍취, 벌개미취 3종이 상대적으로 내건성이 높다고 판단되었다.
        4,000원
        4.
        2008.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To satisfy the demand of higher cutting performance, mechanical properties with tungsten carbide (WC-Co) tool materials were investigated. Hardness and transverse rupture strength with WC grain size, Co content and density were measured. Compared to H, K, and S manufacture maker as tungsten carbide (WC-Co) tool materials were used for high-speed machining of end-milling operation. The three tungsten carbide (WC-Co) tool materials were evaluated by cutting of STD 11 cold-worked die steel (HRC25) under high-speed cutting condition. Also, tool life was obtained from measuring flank wear by CCD wear measuring system. Tool dynamometer was used to measure cutting force. The cutting force and tool wear are discussed along with tool material characteristics. Consequently, the end-mill of K, H manufacture maker showed higher wear-resistance due to its higher hardness, while the S maker endmill tool showed better performance for high metal removal.
        4,000원
        5.
        2016.10 서비스 종료(열람 제한)
        Background : This experiment was carried out to improve the labor-intensive task to construct of the traditional ginseng shading system in Korea. In this experiment the selected shading materials was new 6 kinds that HDPE - knitted- monofilament and taped PE Net, with taking into account of the amount of light and the amount of leakage to screen the UV stabilized 0.3% - 0.6%. Compared with the traditional shading material, the black-shading material (wt. 200g/㎡) and the yellow shading material (wt. 300g/㎡) was suitable for the ginseng growing environments in Korea. Methods and Results : The installation of shading system was the 45 degree slope -2 meter height from the ground with the selected shading materials for the wide structure ginseng cultivation. Temperature and light intensity was measured with a week interval from the surface to a height of 30cm. The two kinds of the 1st selected materials and the traditional black + blue two layer shading materials, aluminum screen, Canada Gintec shading material, total 5 kinds of materials were installed in wide structure. The growing environmental analysis was measured using data logs (watchdog 1600series). Conclusion : In the first selection of shading materials for Ginseng wide structure, the levels of light intensity were higher in order of blue-shading> Aluminum- shading> black-shading order. The temperatures of the under wide structures were lower in order of the black-shading< aluminum-shading screen< blue-shading order, especially the temperature of the black shading material was lower than the outside temperature. For the second selection of shading material of the ginseng wide structure, the black and yellow shading material were superior to the other materials, in the amount of light shading material and growing conditions and the degree of leakage etc. The temperatures of mid-May in wide structures of ginseng cultivation were higher in order of aluminum-screen> Canada shading materials (Gintec Co.) 2 layer material> Yellow shading> black shading order, and also the amounts of light intensity also was shown to be with the same manner
        8.
        2006.06 KCI 등재 서비스 종료(열람 제한)
        더덕 종자의 파종시 산파에 의한 종자 손실이 클 뿐만 아니라 입모 후 잡초 발생에 의한 제초 관리가 어려워 재배 농가에서 어려움이 많아 발아 미세환경을 개선시킬 수 있을 뿐만 아니라 기계화 점파 및 멀칭 재배가 가능하고 제초문제를 해결할 수 있는 더덕 종자 펠렛팅 연구를 실시하였던 바 그 결과를 요약하면 다음과 같다. 다양한 피복물질을 이용한 펠렛팅 종자의 발아율은 PID처리가 가장 높았으며 Illite, PIT, Diatomite, BT 순으로 높게 나타났다. 접착물질은 PVP 처리가 가장 발아율이 높았으며 PVA, XG, CMC, AG 순으로 높게 나타났다. 펠렛팅 종자의 피복소재별 성형율, 강도는 PID 가 가장 좋았으며, 발아율에 가장 좋은 물리적 특성은 수분 접촉시 split형의 1/2 균열이 생기고 수분 흡수력은 S자형의 흡수 양상을 보였다. 토양함수량에 따른 발아율은 50% 조건에서 PID처리가 가장 좋았으며, 수분함수량이 높을수록 펠렛팅 종자의 발아율은 증가되는 경향이었다.