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        검색결과 109

        61.
        2013.04 구독 인증기관·개인회원 무료
        우리나라 전 국토의 6.58%를 차지하고 있는 국립공원은 생태계 현황을 대표하는 지역으로 한국에 서식하는 생물종 39,150종 중 40%에 해당하는 15,727종이 서식하고 있다 (국립공원관리공단, 2012). 특히 환경부에서 지정한 멸종위 기종 221종 중에서 65%에 해당하는 144종이 서식하고 있 어 인간의 간섭 및 개발압력으로부터 마지막 피난처의 중요 한 역할 또한 수행하고 있다. 국립공원은 자연생태계와 자 연 및 문화경관 등을 보전하고 지속가능한 이용을 도모함을 목적으로 하는 자연공원법에 의하여 지정되는 자연공원의 하나로서 자연생태계의 보전뿐만 아니라 지속가능한 이용 또한 고려되어야 한다. 즉, 생물종 서식처의 보존 뿐만 아니 라 탐방객의 이용 또한 고려되어야 하며 이를 위해서는 생 물종의 서식현황 분석은 반드시 선행되어야 할 과제이다. 그러나 생물종이 다양하고 서식처가 광범위하여 종의 전체 적인 서식현황을 분석에는 많은 시간과 비용이 수반된다. 따라서 시간과 공간이 제한되는 산불조심기간 중 산불통제 구간을 대상으로 야생동물의 서식현황을 분석해 보고자 하 였다. 아울러 구례군 지역에 서식하는 야생동물의 서식현황 을 분석하여 보호지역 관리에 기초자료를 제공하고자 하였 다. 월 1회 정기적으로 탐방로를 중심으로 야생동물의 식흔, 배설물 등 흔적을 2010년부터 2012년까지 최근 3년간 모니 터링 하였으며, 모니터링 시 GPS 좌표 측점, 사진촬영, 주변 환경조사 등을 병행하였다. 아울러 무인센서카메라를 10대 설치하여 실체를 확인하였으며, 조사된 자료는 GIS DB로 구축하였다. 최근 3년간, 지리산국립공원 노고단~피아골계곡에서 조 사된 야생동물 흔적은 124건으로 삵 59건, 담비 27건, 족제 비 21건, 멧토끼 10건, 멧돼지 4건, 고라니 2건, 오소리 1건 등이었다. 이중 삵과 담비는 멸종위기종으로서 86건으로 발 견종의 69%를 차지하고 있었다. 특히 봄과 가을철 산불통 제기간 중에는 월평균 19회 관찰되었는데 이는 다른 기간 평균 4회 보다 5배정도 많은 횟수로 탐방객의 출입이 제한 되었을 때 위협요인이 감소됨으로서 서식여건이 보다 안정 화되어 훨씬 많이 발견되고 있음을 알 수 있었다. 2010년부터 2012년 지리산국립공원 구례지역에서 조사 된 야생동물 698건의 서식 분포특성을 분석한 결과 삵 286 건, 담비 139건, 족제비 95건, 수달 53건, 오소리 30건, 멧돼 지 30건, 멧토끼 29건, 너구리 16건, 고라니 13건, 노루 4건, 하늘다람쥐 3건 등이었다. 특히 멸종위기종인 삵, 담비, 수 달, 하늘다람쥐 등이 481건으로 68%를 차지하고 있어 멸종 위기 야생동물의 출현빈도가 매우 높음을 알 수 있었다. 최근 3년간 야생동물 서식현황을 분석한 결과 타기간 보 다 산불방지기간에 출현빈도가 높아 탐방객의 출입에 따른 위협요인을 계량적으로 파악할 수 있었으며, 특히, 봄철 산 불방지기간은 야생동물의 번식기라는 점에서 보다 안정된 서식처를 제공한다는 의의가 있을 수 있다. 또한 멸종위기 종의 흔적이 전체종의 68%가 발견됨으로서 멸종위기종의 서식처를 제공하고 있음을 알 수 있었다. 향후 이러한 결과 를 바탕으로 각 야생동물에 대한 서식처 분석과 더불어 이 를 통한 관리방안이 수립될 필요성이 있다.
        62.
        2012.12 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to suggest specific ways of designing educational programs for school violence prevention by applying a serious online game in Korea. To do this, first, the authors analyzed literature, programs and cases related to school violence. Second, we derived design principles for serious games from the analysis of current game contents. Finally, we wrote a design process to develop the game. A serious game for school violence prevention was specifically designed based on these design principles and processes. It was applied by registering school violence cases, processing the cases, drawing solution plans, and finishing the game. The game is intended for a game user to be self-taught and self-cured by participating in the solution process of school violence cases.
        4,200원
        63.
        2011.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        FePt nanoparticles suspension was synthesized by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine. FePt nanoparticles were coated on a substrate by convective assembly from the suspension. To prevent the coalescence during the annealing of FePt nanoparticles double convective coatings were tried. First convective coating was for silica particle assembly on a silicon substrate and second one was for FePt nanoparticles on the previously coated silica layers. It was observed by scanning electron microscopy (SEM) that FePt nanoparticles were dispersed on the silica particle surface. After annealing at 700˚C for 30 minutes under nitrogen atmosphere, FePt nanoparticles on silica particles were maintained in a dispersed state with slight increase of particle size. On the contrary, FePt nanoparticles that were directly coated on silicon substrate showed severe particle growth after annealing due to the close-packing of nanoparticles during assembly. The size variation during annealing was also verified by X-ray diffractometer (XRD). It was suggested that pre-coating, which offered solvent flux oppose to the capillary force between FePt nanoparticles, was an effective method to prevent coalescence of nano-sized particles under high temperature annealing.
        4,000원
        64.
        2008.12 구독 인증기관 무료, 개인회원 유료
        The present study reports the protective properties of a total methanol extract of B. platyphylla var. japonica against ultraviolet (UV)-C irradiation. Pretreatment of Chinese hamster fibroblast (V79-4) cells with a total methanol extract significantly increased cell survival following 300J/m² of UV-C irradiation. The total methanol extract was further fractionated into 5 fractions: n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these fractions, B. platyphylla var. japonica ethylacetate, butanol and water fractions showed significant protective effects against the cellular damage induced by UV-C irradiation. In order to elucidate the mechanism underlying this protective effect, DPPH (Editor note: abbreviations should be spelled out at first use.) radical scavenging and lipid peroxidation inhibitory activity were measured. Significant radical scavenging and lipid peroxidation inhibitory activities were observed for the ethylacetate fraction. In summary, the present data demonstrate that an extract of B. platyphylla var. japonica has a significant protective effect against UV-C irradiation. The underlying mechanism of this protective effect may involve radical scavenging and inhibition of lipid peroxidation by the B. platyphylla var. japonica extract.
        4,000원
        65.
        2007.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        If you examine the Industrial Disaster Analysis Content that occurs every year in the small and medium enterprise, industrial disaster occurs because of manager's lack of safety and worker's unprepared safety education. Therefore effective safety education systems are needed to offer adequate knowledge and technology to the workers. On this research, to give an effective education way to decrease industrial disaster we administered to the workers who are in charge of 300 workplace in Incheon area to search actual condition of industrial disaster and to disclose a link between industrial disaster and industrial safety education. We put in effect on frequency study and examined x2 using SPSSWIN 10.0. On the research, the results shows that the industrial safety education and training are in effect regularly and the satisfaction are low. But the manager's satisfactions are high through safety education. So it shows that we need to find a way to put in effect safety education to satisfy the workers.
        4,500원
        66.
        2006.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
          Large glass furnaces to produce glass for CRT are housed in huge chambers. It is costly to maintain such a chamber in constant temperature, humidity, and (air) pressure. In this study, first, we show that the process of such a huge furnace, which requir
        4,000원
        69.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        노후콘크리트 포장 수명을 연장하기 위한 방안으로 아스팔트 덧씌우기가 일반적이나 반사균열을 억제하기 어렵다는 단점이 있다. 반사균열을 억제하기 위하여 줄눈부 보수, 응력 완화층 설치가 적용되는 경우가 있으나 반사균열의 진전 속도를 늦추는 제한적인 성공을 보여 왔다. 콘크리트포장 슬래브를 원위치에서 파쇄하여 기층재료로 활용하고 그 위에 덧씌우기 포장을 건설하는 러블라이제이션 공법은 기존 덧씌우기 보강 공법을 갖고 있는 반사균열 문제를 완벽하게 해결할 수 있는 장점을 가지고 있다. 러벌라이제이션 공법을 적용할 경우 파쇄된 노후 콘크리트 포장층 상부층은 40mm-70mm로 파쇄되나 하부층은 100mm이상 되는 경우가 일반적이다. 국내 고속도로와 같이 상대적으로 두꺼운 콘크리트 포장 슬래브를 사용하는 경우 전체 포장 두께를 파쇄하기에 어려움이 있다. 따라서 파쇄된 노후 콘크리트 포장층이 반사균열을 유발시키지 않는 도로기층으로써의 역활을 확보하기 위한 적정 파쇄 깊이를 파악하기 위하여 본 연구에서는 미국 DOT에서 제안한 일반적인 파쇄규격(40mm-70mm)을 기준으로 파쇄 깊이를 0cm, 10cm, 20cm,로 변화시켜가며 반사균열 실내 모사 실험을 수행하여 반사균열 저항 특성을 분석하고 적정파쇄 깊이를 검토하였다.
        4,000원
        73.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, both management and labor are interested in the increasing ratio of musculoskeletal disorders. And the developed countries make efforts to consider a counterplan such as prevention activity of musculoskeletal disorders and application possibility of ergonomic program, because musculoskeletal disorders take large portion out of occupational disease. Especially, small and medium enterprises have bigger problems due to the inferior work condition and environment in comparison with big businesses. This study is to introduce developed countries' cases such as WISE(Work Improvement in Small Enterprises) and OSHA Handbook for Small Businesses and to suggest the program of ergonomic management for small and medium enterprises having comparative difficulties against big businesses in improving work environment and managing ergonomic operations.
        5,200원
        75.
        2002.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Back pain is painful for people at a lower lumber(L4/L5 or L5/S1). It is experienced as a most frequent disaster 70% of workers have suffered from back-pain. Especially, the occurrence rate of back pain for nurses is very high. Therefore, this study investigates female nurses who worked as a part of a medical cost management team, which mainly deal with the medical insurance in a general hospital at Seoul area. These nurses had different job tasks, which used computers for 50% of their time, so it can be treated as VDT workers. As a first step of this project, a muscle fatigue was measured for these special VDT workers. First, survey for nurses was conducted to figure out what is a real problem of them. Second, to evaluate an experimental data, a medical cost management team was chosen for subjects. Areas of measurement were 3 places that were the trapezius (TR), the medial deltoid (MD), and the erector spine muscle (ES: L4/L5). These areas are most frequently used, so they were chosen for this study. Measurements were taken before work and after work. From these measurements, it was revealed that a fatigue really comes from their main VDT task excluding natural fatigue after work, so their work environment need to be corrected.
        4,600원
        79.
        2023.11 서비스 종료(열람 제한)
        Wolsong Unit 1 nuclear power plant, which was permanently shut down in 2019, has a 678 MWe calandria vessel of the CANDU-6 type pressurized heavy-water reactor model. The calandria inside the vault is a horizontal cylindrical vessel made of stainless steel with a length of 7.8 m and a thickness of 28.6 mm. For the entire dismantling processes of a nuclear power plant, dismantling works cannot be performed using only one cutting technology and method, and when performing dismantling of a calandria vessel, various systems and components can be used for cutting and dismantling. The calandria vessel is located in a concrete compartment called a vault, and in order to safely dismantle the calandria vessel, the spread of radioactive contaminants from inside of the vault to the outside must be prevented. We designed dismantling processes using the laser cutting method to dismantle the calandria vessel and end shields. We must minimize the risk of internal radiation exposure to workers from aerosols derived from the thermal cutting processes. Therefore, we need a way to prevent secondary contamination from spreading outside the vault and within the reactor building. The path through which radioactive contaminants move is that the flying airborne products generated during the cutting process inside the vault where the calandria is located do not stay in place but spread outward through the opening of the RM-Deck structure at the top. Therefore, facilities or devices are needed to effectively prevent the spread of radioactive contaminants by blocking the expected movement path. By using these facilities or devices, it is possible to prevent the movement of radioactive aerosol particles between the location of the worker and the location of the cutting area where the calandria is located, thereby preventing internal exposure through the worker’s breathing. In addition, by using these, the cutting area where airborne pollutants are generated can be designed as an isolated work space to prevent the spread of radioactive contaminants. In this study, we propose a method of facilities for confining radioactive aerosol particles and preventing the spread of contamination when thermal cutting of the calandria vessel within the vault.
        80.
        2023.11 서비스 종료(열람 제한)
        Currently, the most promising fuel candidate for use in sodium fast reactors (SFRs) is metallic fuel, which is produced by a modified casting method in which the metallic fuel material is sequentially melted in an inert atmosphere to prevent volatilization, followed by melting in a graphite crucible, and then injection casting in a quartz (SiO2) mold to produce metallic fuel slugs. In previous studies, U-Zr metallic fuel slugs have been cast using Y2O3 reaction prevent coatings. However, U-Zr alloy-based metallic fuel slugs containing highly reactive rare earth (RE) elements are highly reactive with Y2O3-coated quartz (SiO2) molds and form a significant thickness of surface reaction layer on the surface of the metallic fuel slug. Cast parts that have reacted with nuclear fuel materials become radioactive waste. To decrease amount of radioactive waste, advanced reaction prevent material was developed. Each RE (Nd, Ce, Ln, Pr) element was placed on the reaction prevent material and thermal cycling experiments were carried out. In casting experiments with U-10wt% Zr, it was reported that Y2O3 layer has a high reaction prevent performance. Therefore, the reaction layer properties for RE elements with higher reactivity than uranium elements were evaluated. To investigate the reaction layer between RE and NdYO3, the reaction composition and phase properties as a function of RE content and location were investigated using SEM, EDS, and XRD. The results showed that NdYO3 ceramics had better antireaction performance than Y2O3.
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