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        검색결과 15

        1.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        After nuclear power plants are permanently shut down and decommissioned, the remaining irradiated metal components such as stainless steel, carbon steel, and Inconel can be used as neutron absorber. This study investigates the possibility of reusing these metal components as neutron absorber materials, that is burnable poison. The absorption cross section of the irradiated metals did not lose their chemical properties and performance even if they were irradiated over 40-50 years in the NPPs. To examine the absorption capability of the waste metals, the lattice calculations of WH 17×17 fuel assembly were analyzed. From the results, Inconel-718 significantly hold-down fuel assembly excess reactivity compared to stainless steel 304 and carbon steel because Inconel-718 contains a small amount of boron nuclide. From the results, a 20wt% impurity of boron in irradiated Inconel-718 enhances the excess reactivity suppression. The application of irradiated Inconel-718 as a burnable absorber for SMR core was investigated. The irradiated Inconel-718 impurity with 20wt% of boron content can maintain and suppress the whole core reactivity. We emphasize that the irradiated metal components can be used as burnable absorber materials to control the reactivity of commercial reactor power and small modular reactors.
        4,900원
        3.
        2019.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Port of Pyeong Taek is located on the west coast, meaning that the difference between the rise and fall of tide is great (flood tide 1.8 to 2.9 knots, ebb tide 1.6 to 2.9 knots). Due to mainly N~NW’ly strong winds & high waves during winter, navigating as well as loading & discharging vessels must focus on cargo handling. The strong tidal and wind forces in the Port of Pyeong Taek can push an LNG carrier away from its berth, which will end up causing forced disconnection between the vessel’s cargo line and shore-side loading arm. The primary consequence of this disconnection will be LNG leakage, which will lead to tremendous physical damage to the hull and shore-side equipment. In this study, the 125K LNG Moss Type ship docked at No. 1 Pier of the Pyeong Taek is observed, and the tension of the mooring line during cargo handling is calculated using a combination of wind and waves to determine effective mooring line and mooring line priority management. As a result if the wind direction is 90° to the left and right of the bow, it was found that line monitoring should be performed bearing special attention to the Fore Spring Line, Fore Breast Line, and Aft Spring Line.
        4,000원
        4.
        2019.04 구독 인증기관·개인회원 무료
        Japanese pine sawyer, Monochamus alternatus, is the main pest that mediates pine wilt nematode, Bursaphelenchus xylophilus, that causes serious damage to pine forests. In this study, we studied the strategy to control M. alternatus using entomopathogenic fungi. The fungi were collected from soil by an insect-baiting method and two fungal isolates (Metarhizium anisopliae JEF-197 and JEF-279) showed high virulence against M. alternatus. The Metarhizium isolates were evaluated for insecticidal activity against M. alternatus by spray treatment on live pine trees and wintering trees, and the M. anisopliae JEF-197 showed high insecticidal activity. In addition, the interaction of fungi and M. alternatus were analyzed by RNA-seq. This result can contribute to the development of insect control agents using entomopathogenic fungi.
        5.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the effects of low-intensity cardiac rehabilitation exercise on the cardiac function and the degree of fibrosis in an older white rat model. This study used male Sprague- Dawley white rats that were 50 weeks old. After the acute myocardial infarction induction, Twenty of the rats were randomly allocated into an experimental group and a control group, and each of the groups consisted of 8 rats. In the experimental group, the exercise was conducted for six weeks, 30 minutes a day, five days a week, using a Rotarod treadmill for animals. The degree of myocardial fibrosis was significantly repressed in the experimental group(13.69±1.90%) and in the control group(15.67±1.54%)(p<0.05). However, fractional shortening and ejection fraction did not show a significant difference. The results of this study suggest that cardiac rehabilitation with low intensity treadmill exercise repress the myocardial fibrosis.
        4,000원
        7.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of the study was to investigate effects of Low intensity cardiac rehabilitation, using a treadmill, on the myocardial structure. We identified the effects by analyzing changes in the rats' weights and the results of biopsies. Twenty Sprague-Dawley male rats, 50 weeks old, were randomly divided into the exercise group and the control group. myocardial infarction( MI) was induced by ligaturing their left anterior descending artery. After the acute MI induction, two rats of each group began to fall dead, therefore, eight of each group completed at the end of the experiment. We used treadmills for animals for the exercise group. This exercise group performed 30 minutes of exercise five times per week for six weeks, while the control group did not perform any exercise. No statistically significant differences in weight were found in within group comparison and between group comparison. Furthermore, we observed histological changes in the myocardium using Hematoxylin & Eosin and Masson's trichrome staining in both groups. Low-intensity exercise inhibited myocardial fibrosis, may serve as a reference in the cardiopulmonary field, which plays a role in rehabilitating patients with cardiac disorders, including acute MI.
        4,000원
        8.
        2016.05 서비스 종료(열람 제한)
        Background : Indigenous plant in Jeju island, Sasa quelpaertensis Nakai, belongs to the Bambusoideae and inhabit around Mt. Halla. According to the ancient book such as Dongui Bogam, Sasa quelpaertensis Nakai have been known to possess the antidiabetic, anti-inflammatory, and anti-diuresis effect. However, because of gradual upturning temperature, Sasa quelpaertensis Nakai was spread out to wider area and intrude the habitat that other plant species are growing. Recently, although the study to seek effective use of Sasa quelpaertensis Nakai, the investigation about functional properties has not been taken place enough. Methods and Results : To assess the inhibitory activity of melanin synthesis, we employ the tyrosine as substrate and measure the formation of dopaquione at 490 nm. Firstly, 0.1 mM potassium phosphate buffer and tyrosinase were mixed and incubated at 37℃. After incubating at 37℃, the absorbance rate was measured at 490 nm. The value was compared with positive control, arbutin, and calculated with the rate between sample and control value. Previously, formononetin, glabrene, glabridin, glabrol, artocarbene, dihydromoriin are known as effective substances for whitening. Moreover, the arbutin, which was separated from Arctostaphylos uva-ursi (L.) Sprengel, are widely used in cosmetic field. Arbutin inhibits tyrosinase and tyrosine synthesis, which induce blackish pigmentation. Practically, the Sasa quelpaertensis Nakai leaf ethanol extract depend on different solvent condition, whole extracts showed stronger inhibition than arbutin. Especially, 60% ethanol extract exhibited twice higher tyrosinase inhibitory activity than arbutin, whereas least inhibitory activity was seen in 20% ethanol extract. Conclusion : In this study, a attempt was made to investigate the tyrosinase inhibitory activity of Sasa quelpaertensis Nakai leaves extracted by different solvent condition. In the results, each extracts was prior to arbutin. Yet, 20% ethanol extract was lowest, but on the one hand, 60% ethanol extract demonstrated the highest tyrosinase inhibitory activity.
        9.
        2015.02 KCI 등재 서비스 종료(열람 제한)
        LED 광원을 달리하여 재배한 감초지상부의 항산화, 항돌연 변이원성을 평가하였다. BL-0에서 DPPH 라디칼 소거활성에 서 EC50이 3.02 ± 0.13 ㎍/㎖와 ABTS 라디칼 소거활성은 EC50 이 2.18 ± 0.18 ㎍/㎖와 환원력이 가장 높게 나타났다. 폴리페놀 함량은 2.93 ± 0.11 g/100 g으로 가장 높게 나타났으며, RL-0 에서는 항산화 활성이 가장 낮게 나타났다. 항돌연변이원성 평 가에서 직접변이원인 1-NP에 대해 모든 실험군에서 돌연변이 억제효과를 나타냈으며, 간접변이원인인 Trp-P-1, Trp-P-2, AFB1에 대해서는 BL-0에서 가장 높은 돌연변이 억제효과를 나 타냈고, 2-AA에서는 RL-1에서 돌연변이 억제가 높게 나타났 다. 청색광 LED (650 ㎚)와 적색광 LED (450 ㎚)를 이용하여 재 배한 감초지상부의 성분변화를 관찰하기 위해 GC/MS를 이용 해 분석한 결과 25분에서 RL-1에서만 cytidine이 검출되었고, 37분에서 BL-0에서만 2-bromotrimethylene glycol이 특정적 으로 검출되었다. 이는 LED광원 조건에 따라 감초 경엽의 성분 이 차이가 있음을 보여준다. 이 성분들이 생리활성에 어떤 영향 을 주는지는 더 검토해야할 부분이다.
        14.
        2007.02 KCI 등재 서비스 종료(열람 제한)
        The effect of precoating of silica with polyamine surfactants on the adsorption of five model compounds containing asphalt-like functionalities was studied. Hexadecyltrimethylammonium chloride (HDTMA) and 1-hexadecylamine were used for silica precoating. The model compounds representing five asphalt functionalities were benzoic acid, phenol, benzylbenzoate, benzophenone, and quinoline. All the adsorption isotherms conformed well to the Langmuir adsorption model. All the model compounds showed decreased adsorption with the HDTMA precoating. However, two acidic compounds, benzoic acid and phenol, showed enhanced adsorption on the silica precoated with 1-hexadecylamine. In aqueous solutions, the adsorption of the acidic compounds were in the following order: silica precoated with 1-hexadecylamine > silica precoated with HDTMA > uncoated silica.