• Composites Research
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• 제31권6호
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• pp.398-403
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• 2018

최근 플라스틱 폐기물로 인한 환경오염, 미세플라스틱의 생태계 교란 및 인체축적이 큰 문제로 떠오르고 있다. 이를 대체하기 위하여 친환경 수지 및 천연섬유 기반의 복합재료가 개발되어 왔으나 합성섬유 기반의 복합재료에 비하여 기계적 물성이 크게 떨어진다는 단점이 있다. 본 연구에서는 천연섬유인 황마섬유(jute fiber)의 기계적 물성을 향상시키기 위하여 해초로부터 친환경 나노섬유를 추출 후 첨가제로 사용하였다. 핸드 레이업 공정을 이용하여 복합재료를 제조하였으며, 인장, 굽힘, 낙추충격시험을 통하여 나노섬유가 천연섬유 복합재료의 기계적 물성 향상에 효과적임을 확인할 수 있었다.

• Steel and Composite Structures
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• 제24권2호
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• pp.191-200
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• 2017

Impact resistance and weight are important features for ballistic materials. Kevlar fibres are the most widely reinforcement for military and civil systems due to its excellent impact resistance and high strength-to-weight ratio. Kevlar fibres or spectra fiber composites are used for designing personal body armour to avoid perforation. In this study, the ballistic impact behaviour of Kevlar/filled epoxy matrix is investigated. Three different fillers, nanoclay, nanocalcite and nanocarbon, were used in order to increase the ballistic impact performance of Kevlar-epoxy composite at lower weight. The filler, nanoclay and nanocalcite, content employed was 1 wt.% and 2 of the epoxy resin-hardener mixture while the nanocarbon were dispersed into the epoxy system in a 0.5%, 1% and 2% ratio in weight relating to the epoxy matrix. Specimens were produced by a hand lay-up process. The results obtained from ballistic impact experiments were discussed in terms of damage and perforation. The experimental tests revealed a number of damage mechanisms for composite laminated plates. In the ballistic impact test, it was observed whether the target was perforated completely penetrated at the back or not. The presence of small amounts of nanoclay and nanocalcite dispersed into the epoxy system improved the impact properties of the Kevlar/epoxy composites. The laminates manufactured with epoxy resin filled by 1 wt.% of nanoclay and 2 wt% nanocalcite showed the best performance in terms of ballistic performance. The addition of nanocarbon reduced ballistic performance of Kevlar-epoxy composites when compared the results obtained for laminates with 0% nanoparticles concentration.

• 한국강구조학회 논문집
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• 제24권3호
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• pp.349-360
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• 2012

본 논문은 GFRP 슬래브 교량 상부구조에 대한 장기성능, 내하력, 사용성 및 구조적 안전성의 상세한 평가를 기술하고 있다. 국내 최초로 완전 GFRP 슬래브 교량이 2002년 5월에 가설되었다. GFRP 슬래브 교량은 단순지지로 지간 10.0 m, 폭 8.0 m 인 2차선으로 설계되었다. 본 GFRP 슬래브교량은 콜루게이트(corrugate) 심재를 갖는 샌드위치 구조로서 유리섬유와 비닐 에스테르를 사용하여 수적층으로 제작되었다. GFRP 슬래브 교량의 장기성능 평가는 2002년 수행되었던 동일한 현장재하시험으로 2004, 2011년에 실시되었다. GFRP 슬래브교량은 예상되었던 대로 공용 중에서 구조적 문제점이 없이 성능이 잘 발휘되고 있었음을 평가를 통하여 나타내고 있다. 본 평가 자료는 GFRP 슬래브 교량의 내하력 평가에 대한 기초자료와 완전 GFRP 슬래브교량 상부구조의 장기성능의 일부자료로서 제공될 수 있을 것이다.

• Journal of Mechanical Science and Technology
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• 제17권1호
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• pp.1-10
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• 2003

This paper summarizes the results of the fatigue test of four composite bridge decks in extreme temperatures (-30$^{\circ}C$ and 50$^{\circ}C$ ). The work was performed as part of a research program to evaluate and install multiple FRP bridge deck systems in Dayton, Ohio. A two-span continuous concrete deck was also built on three steel girders for the benchmark tests. Simulated wheel loads were applied simultaneously at two points by two servo-controlled hydraulic actuators specially designed and fabricated to perform under extreme temperatures. Each deck was initially subjected to one million wheel load cycles at low temperature and another one million cycles at high temperature. The results presented in this paper correspond to the fatigue response of each deck for four million load cycles at low temperature and another four million cycles at high temperature. Thus, the deck was subjected to a total of ten million cycles. Quasi-static load-deflection and load-strain responses were determined at predetermined fatigue cycle levels. Except for the progressive reduction in stiffness, no significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

• Composites Research
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• 제32권6호
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• pp.368-374
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• 2019

무기필러가 첨가된 현무암섬유 강화 에폭시 복합재료를 제조하여 그 특성을 평가하였다. 첨가된 무기필러는 각각 수산화마그네슘, 수산화알루미늄, 알루미나, 베마이트이며 이를 첨가제로한 에폭시 수지를 현무암섬유에 핸드레이업으로 함침시킨 후 hot pressing하여 수지 함침량이 30 wt%인 섬유복합재료를 제조하였다. LOI 평가 결과 BFRP의 LOI (28.9)는 에폭시 수지 (21.4)에 비해 향상된 것을 확인하였으며 무기필러가 첨가될 경우 그보다 더욱 향상되는 것을 확인하였다. 또한 무기필러가 첨가된 복합재료는 무기필러가 첨가되지 않은 복합재료에 비해 콘칼로리미터 시험에서 PHRR, THR, TSR 등이 감소하여 무기필러 첨가에 따른 난연 특성 향상을 확인하였다.

• 한국문헌정보학회지
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• 제23권
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• pp.63-106
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• 1992

The opening period of Korea was the period of modernisation amidst the conflicts between conservative and progressive sections with penetration of Western powers after 1876. With the opening modernisation accompanied modernisation of education. Missionary schools established by protestant missionaries played a crucial role in educational modernisation in the period of opening. In this article, the process of educational modernisation and the ways in which the ideas of democracy and equality were taught in the earliest schools, Paejae, Ewha, Kyoungsin and Chungsin are analysed through the method of bibliographical investigation of the textbooks used by these schools. No textbook prior to 1900 was found and in general there were no textbooks such as we know today. Usually English reading material and the Bible were the main teaching materials. Teachers kept their own copies of hand-written texts which were translated versions of American textbook. Since the same teacher taught in a number of schools, they shared same curriculum. In the early period, English Bible was taught so that English and the Bible lessons were not separated but gradually history and geography were added. Teaching of Hangul, and Korean history were added to encourage the sense of national identity and patriotism. In the case of Chungsin, for biology class, pupils were sent to Che-jung-won to learn human physiology, chemistry and physics, which shows an emphasis on science education. Vocational education was carried out; in the case of Paejae, a printing workshop was set up enabling students to earn some money at the same time as learning. Also in Kyungsin, skills of woodwork and basket weaving were stressed. Ewha also held a bazaar of the work made in sewing classes. Establishment of missionary schools brought about a great contribution in modernising Korean society and the Christian spiritual education of these schools lay the foundation for building democracy in Korea.

• 한국산학기술학회논문지
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• 제15권8호
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• pp.4756-4762
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• 2014

운전 중에 손상된 풍력발전기 블레이드는 전통적으로 에폭시 수지를 사용하는 수적층 공법으로 수리가 되어 왔다. 수적층 공법의 접착 강도는 높지 않으며 에폭시 수지는 낮은 온도에서 경화특성이 좋지 않은 단점을 가지고 있다. 본 논문에서는 손상된 블레이드 수리를 위하여 폴리에스터 수지를 사용하는 진공성형 공법을 제안한다. 진공성형 공법은 수지를 균일하게 분포시키는 장점이 있으며, 폴리에스터 수지는 저온에서 에폭시보다 경화가 더 잘되는 특성을 가지고 있다. 상온에서 수리가 이루어 질 때, 제안한 방법을 사용할 경우 전통적인 방법에 비하여 평균 접착강도가 최대 77.7% 상향되었다. 섭씨 15도와 5도에서 제안한 방법을 사용하여 수리가 이루어 질 때, 동일한 온도에서 전통적인 방법으로 수리한 경우보다 평균 접착강도가 향상되었다. 전통적인 방법을 사용하여 수리가 불가능한 저온에서도, 본 논문에서 제안한 방법을 사용할 경우 수리가 가능하게 되었고 상온에서 전통적인 방법으로 수리가 된 경우보다 더 좋은 접착강도를 얻을 수 있게 되었다.

• 동서간호학연구지
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• 제8권1호
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• pp.135-146
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• 2003

Moxibustion plays an important role not only in the medical service, but also in the health care of Korea. So this study attempted to review of moxibustion and analyze of domestic study trend. And it also intends to examine the usefulness of moxibustion treatment in Korean nursing intervention. "Donguibogam" is famous for the most comprehensive medical book in ancient Korea, indicates that moxibustion makes up a large part of it and that its contents were composed of material, size, time, caring of one's health, indication, operational procedure, contraindication in the documented in the 25 reference books. Also, It confirms that it has been widely used since old times. Especially, it seems to be a great help to researchers because its content lay a theoretical foundation. From the literature, we identified that moxibustion was most widely using method for health promotion and an efficacious cure for a disease. I searched and investigated the journals and dissertations supplied by KERIS and RICH with the key word "moxibustion". Of 10 articles with moxibustion intervention, the trend of domestic studies shows, that of an area relating to nursing was 5. Therefore, moxibustion intervention steadily increases in frequency in nursing academic circles year by year. But there is no distinction between hand moxibustion and moxibustion. According to the above results, we need to develop moxibustion learning program and well designed experimental study with moxibustion for Korean Nursing intervention.

• Composites Research
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• 제33권4호
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• pp.213-219
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• 2020

최근 플라스틱 폐기물로 인한 환경 문제가 이슈화되면서 친환경 소재에 대한 관심이 점점 증가하고 있으며, 이에 따라 천연섬유를 활용한 복합재의 연구가 지속적으로 이루어지고 있지만 친환경 복합재의 강도나 계면 접착력에 대한 연구가 많이 부족한 실정이다. 복합재료의 강도나 계면 접착력을 향상시키는 방법들 중 한 가지 방법은 나노 입자를 첨가하여 기계적 물성을 향상시키는 방법이 있다. 본 연구에서는 기존에 사용되는 고가의 나노소재를 대체할 수 있는 친환경적이면서 경제적인 천연섬유를 해초로부터 추출하여 첨가제를 제조하고, 복합재료의 제조 및 기계적 특성평가를 수행하였다. 시험결과 제조한 첨가제가 복합재료의 인장, 굽힘, 충격 등의 물성 향상에 효과가 있을 뿐만 아니라 친환경성과 경제성도 가지고 있어 후속연구를 통해 다양한 분야에 적용할 수 있을 것이라 기대된다.

• 사상체질의학회지
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• 제16권2호
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• pp.71-83
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• 2004

1. Objectives The purpose of nursing is to promote health and well-being for all persons. It is connected with Sasang Constitution theory have regard for viewpoint by other's a special quality & individual difference. A nursing is helping behavior to recover health, disease protection & self care ability through health education. There is need for Oriental nursing research continually. 2. Methods This study attempted to develop a fundamental nursing theory for Sasang Constitution on the focus "Dongyi Soose Bowon Sasang Chobongyun". Because the book is important to understand Lee Je-ma's early medical mind and thinking. 3. Results and Conclusions The Sasang Constitution theory lay great emphasis upon health caring medicine to promote health according to self Constitution at normal times, preventive medicine to manage byself body and mind in ordinary times. The way of Sasang Constitutional Nursing Theory is expected to set up a landmark stone in Korean nursing. It is also can product a new nursing theory. In view of 'Nature and Order' is explained inborned general human being who were gifted from nature. On the other hand, in view of 'Knowledge and Deed' based on Constitutions are explained autonomical human being. There are depend on independant control and make efforts themselves or not. It have a connected in four paradigm (human- environment-health- nursing) of nursing theory. The history taking stage claim caring of sick-people before. The ways of assesment for sick-people have to know a process of illness.