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        검색결과 15

        1.
        2022.10 구독 인증기관·개인회원 무료
        KINAC has regulated cyber security of nuclear facilities based on「Act on Physical Protection and Radiological Emergency」and KINAC/RS-015 “Security for Computer and Information System of Nuclear Facilities”, a regulatory guide. By that law and regulatory guide, nuclear licensees shall protect digital assets so-called CDAs, which are conducting safety, security, and emergency preparedness functions from cyber-attack. First of all, to protect CDAs from cyber-attack, licensees should identify CDAs from their assets according to the RS-015. The identification methods are provided in another regulatory guide, RS-019. To research the best practice, a reference case is selected as a U.S. case. In this study, a comparison analysis was conducted especially focused on EP CDAs identification methodology between R.O.K. and U.S., because the regulation basis is relatively insufficient in R.O.K., and improvement plans for the cyber security regulations in R.O.K were proposed. From the analysis, it was identified that detailed methods to identify EP function are provided in NEI 10-14 “Identifying Systems and Assets Subject to the Cyber Security Rule” published by Nuclear Energy Institute (NEI), an institute of nuclear power reactor licensees. Also identified that the definition of EP function is provided clearly in NEI 10-04 based on related regulation, 10 CFR 50.47 “Emergency Plans”. In that regulation, licensees shall follow and maintain the effectiveness of an emergency plan that meets the sixteen planning standards of 10 CFR 50.47(b). So, these sixteen planning standards correspond to the emergency preparedness functions. In NEI 10-04, scoping considerations for emergency preparedness function are provided referring to sixteen planning standards. Moreover, in that scoping considerations, planning standards, planning standard functions and 10 CFR 73.54 “Protection of digital computer and communication systems and networks” scoping guidance are provided, so, licensees identify EP CDA in their assets conveniently. In case of R.O.K., because these sixteen planning standards are not established, there is an ambiguity in identifying EP CDAs. The only related provision is “Detailed Standards for Establishment of Emergency Plan”. To resolve the ambiguity, it is needed to analyze sixteen planning standards in 10 CFR 50.47(b) and “Detailed Standards for Establishment of Emergency Plan”. Then, should be developed ‘scoping considerations for emergency preparedness function’ based on the analysis as provided in NEI 10-04.
        2.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, nitric acid oxidation with varied treatment temperature and time was conducted on the surfaces of polyacrylonitrile- based ultrahigh modulus carbon fibers. Scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and surface tension/dynamic contact angle instruments were used to investigate changes in surface topography and chemical functionality before and after surface treatment. Results showed that the nitric acid oxidation of ultrahigh modulus carbon fibers resulted in decreases in the values of the crystallite thickness Lc and graphitization degree. Meanwhile, increased treating temperature and time made the decreases more obviously. The surfaces of ultrahigh modulus carbon fibers became much more activity and functionality after surface oxidation, e.g., the total surface energy of oxidized samples at 80 °C for 1 h increased by 27.7% compared with untreated fibers. Effects of surface nitric acid oxidation on the mechanical properties of ultrahigh modulus carbon fibers and its reinforced epoxy composites were also researched. Significant decreases happened to the tensile modulus of fibers due to decreased Lc value after the nitric acid oxidation. However, surface treatment had little effect on the tensile strength even as the treating temperature and processing time increased. The highest interfacial shear strength of ultrahigh modulus carbon fibers/epoxy composites increased by 25.7% after the nitric acid oxidation. In the final, surface oxidative mechanism of ultrahigh modulus carbon fibers in the nitric acid oxidation was studied. Different trends of the tensile strength and tensile modulus of fibers in the nitric acid oxidation resulted from the typical skin–core structure.
        4,500원
        4.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An organophosphorus pesticide, ethoprophos, has been widely used in agriculture to control major insect pests. As ethoprophos is a well-known neurotoxin, its accumulation in soils and groundwater is concerning worldwide. In this study, we constructed an artificial ethoprophos-enrichment soil system, and its active concentration in soils was measured by gas chromatography on 15-days intervals during 90 days after ethoprophos treatment. Furthermore, the changes in bacterial community and microorganisms responsible for efficient bioremediation were investigated while ethoprophos was degraded in soils. From 15 to 60 days after the treatment, ethoprophos was actively degraded in soils and members of genera Collimonas and Sphingobium appeared dominantly in a natural microbial community especially in 60-days-after-treatment soil. We isolated a bacterium EP60845 from this soil sample, showing significant ethoprophos biodegradation activity in vitro. When we challenged EP60845 strain into ethoprophos-enrichment soils (250 mg/kg of soil), most ethoprophos was removed within 5-days. Phylogenetic 16S rRNA gene sequence analysis and biochemical properties by API 20GN kit demonstrated that the EP60845 strain was a novel Sphingobium sp., which could be used as an efficient ethoprophos- degrading agents for bioremediation purposes.
        4,000원
        5.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        동적 불안정 좌굴현상에 관한 연구는 다소 발표되고 있으나 주기성을 가진 히중하에서의 동적 좌굴을 다룬 연구는 그리 많지 않은 편이다. 주기성을 가진 하중하에서의 거동은 스텝 하중하에서 거동과는 다르리라 예상된다. 본 논문에서는 동적 불안정의 기본 메커니즘을 파악하기 위하여 2자유도의 얕은 EP(Elliptic Paraboliodal)쉘이 정현파 하중을 받았을 때의 직접좌굴과 간접좌굴 현상을 조사한다. Newma가-β법에 의한 수치적분을 이용하여 비선형 운동 방정식의 변위응답을 구하고 얻어진 비선형 변위응답으로 위상곡면선의 끌개를 비교하고, FFT(Fast Fourier Transform)에 의한 연속 응답 스펙트럼을 구해 동적 불안정 특성에 관해서 분석한다. 그 결과 동적 좌굴하중은 구조물의 고유주기와 외력 탁월진동수와의 관계에 크게 영향을 받는다.
        4,000원
        6.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        쉘형 구조물의 동적 불안정 문제를 다룬 연구결과는 다소 발표되고 있으나 위상곡면을 이용하여 카오스 생성에 관한 기본적 현상을 다룬 연구는 거의 없는 실정이다. 동적 비선형 문제에서 여러 가지 초기조건에 의해 불안정 현상이 민감하게 발생하는 이유를 파악하기 위해서는 위상곡면에서 끌개의 특성을 조사하여 동적 불안정 생성과정을 검토하는 일은 매우 중요하다. 본 연구에서는 얕은 EP 쉘이 스텝하중을 받을 때, 직접 좌굴과 간접 좌굴의 발생 경로를 파악하기 위하여 Galerkin 법에 의해 전개된 이산화 방정식을 구한다. 이를 수치해석 기법으로 위상곡선과 연속응답스펙트럼을 구해 동적 불안정 특성을 규명한다.
        4,000원
        11.
        2017.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We have studied the technology to extend the storage period of ‘Seolhyang’ strawberries using modified atmosphere package (MAP) and ethyl pyruvate (EP) treatment for domestic distribution and export. The selected ripe strawberries harvested on December 28, 2016 at the Sancheong farmhouse were transported to the laboratory for 2 h and tested. After a day’s precooling at 4℃, the strawberries were divided into seven experimental groups. These groups were control, active MAP using low density polyethylene (LDPE), active MAP using polyamide (PA), active MAP using PA with EP treatment, passive MAP using LDPE, passive MAP using PA and passive MAP using PA with EP treatment. Quality analysis was carried out every 4 days during the storage period of 16 days. During the storage period of 16 days, MAP decreased from 3.5% to less than 1.1% in weight loss ratio compared with control, and decreased from 36% to less than 7% in fungal incidence. In the case of fungi in the EP treatment group, hyphae did not grow on the outside of the strawberry but grew to the inside. This tendency was similar to that in the low oxygen and high carbon dioxide environment of the MAP, the mycelium of the fungus did not grow outside of the strawberry. Fungi are the biggest problem in the distribution and export of strawberries, and these results suggest that MAP alone could inhibit mold and increase shelf life.
        12.
        2011.01 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 분산제 코팅을 통해 성능 개선된(EP) 나일론 섬유를 혼입한 자기충전 콘크리트의 가능성을 알아보고자 하였으며, 이를 위한 실험 방법으로 나일론 섬유 길이와 다른 유기계 섬유(폴리프로필렌, 셀룰로오스)를 혼입한 경우 그리고 광물질혼화재(고로슬래그 미분말, 플라이애쉬)의 종류를 달리 혼합한 2성분계 및 3성분계의 경우를 가지고 자기충전 콘크리트의 특성을 검토하였다. 이 실험 결과를 토대로 하여 실구조물 적용을 위한 Mock-up Test를 성능 개선된 나일론 섬유를 혼입한 자기충전콘크리트 와 일반콘크리트를 비교하여 실구조물 활용 가능성을 검토 하였다. 그 결과 굳지 않은 자기충전 콘크리트의 특성, 경화된 자기충전 콘크리트의 특성 및 내구특성을 종합해 볼 때 성능 개선된(EP) 나일론 섬유가 우수함을 알 수 있었고,성능 개선된 나일론 섬유에 따른 광물질 혼화재 사용에서는 플라이애쉬 보다 고로슬래그 미분말이 우수함을 알 수 있었다.
        15.
        1999.09 KCI 등재 서비스 종료(열람 제한)
        The importance of service quality in any service industry cannot be disputed. Shippers have increased expectations concerning the quality of shipping service they receive and carriers are struggling to meet these expectations. This struggle between shipper and carriers would suggest that there is room to improve much more understandings of how shipper define shipping service quality in the carriers' perspectives. This is an empirical investigation and study on the measurement of customer response and service quality as perceived by customer in the international transportation logistics system. The purpose of this study is to clarify factors of shipping service quality on the basis of service marketing concept. In order to fulfill the objectives, this paper combined research tools that include both empirical study and documentary research. Data was gathered from 132 freight forwarder by the use of questionnaire. In this study, the established hypotheses were generated on the basis of the service quality evaluation model(SERVQUAL, SERVPERF, and EP) and Gap model.