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        검색결과 4

        1.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Environmental changes exert harmful effects on organisms inhabiting coastal regions. These changes are also associated with reduced production in aquaculture farms. In this study, we investigated internal and external responses of two Bivalvia species (Crassostrea gigas and Mytilus galloprovincialis) in Gamak Bay under stressful environmental conditions in aquaculture farms. We investigated external responses such as weight, size, and environment exposure time, and analyzed the expression of the HSP70 gene. C. gigas HSP70 gene expression level was significantly high in the C3 aquaculture farm site, but the weight and size of C. gigas were high in the C2 aquaculture farm site. The response of C. gigas HSP70 mRNA was associated with the environmental exposure time in each aquaculture farm. Expression of M. galloprovincialis HSP70 gene was found to be significantly higher in the M2 aquaculture farm site than in the M1 site, whereas the weight of M. galloprovincialis was observed to be higher in the M1 site. The size and environmental exposure time of M. galloprovincialis were similar between M1 and M2 sites. In addition, HSP70 sequences of C. gigas and M. galloprovincialis showed high similarity with that of another marine species. According to our results, there were differences in internal responses following environmental stress in aquaculture farms, with respect to HSP70 gene expression. The results suggest that the HSP70 gene is a useful molecular indicator for monitoring stress responses in Bivalvia species in the field.
        4,000원
        2.
        1994.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This work studies for boiling and condensation heat transfer performance of trapezoidally shaped integral-fin tubes having fin densities from 748fpm to 1654fpm. For comparison, tests are made using a plain tube having the same inside and outside diameter as that of the root of fins of finned tubes. Hahne's theoretical model and Webb's theoretical model are used to predict the R-11 boiling heat transfer coefficient and condensing heat transfer coefficient respectively for plain tube and all integral-fin tubes. Experiments are carried out using R-11 as working fluid. This work is limited to film-wise condensation and pool boiling on the outside surface of plain tube and 4 low integral-fin tubes. In case of condensation, the refrigerant condenses at saturation state of 32℃ on the outside tube surface cooled by coolant and in case of boiling. the refrigerant evaporates at saturation state of 1bar on the outside tube surface. The amount of non-con-densable gases in the test loop is reduced to a negligible value by repeated purging. The actual boiling and condensing processes occur on the outside tube surfaces. Hence the nature of this surface geometry affects the heat transfer performances of condenser and evaporator in refrigerating system. The condensation heat transfer coefficient of integral-fin tube is enhanced by both extended tube surface area and surface tension. The ratio of the condensation heat transfer coefficients of finned to plain tubes is greater than that of surface area of finned to plain tubes, while ratio of the boiling heat transfer coefficient of finned to plain tubes shows reverse result. As a result, low integral-fin tube can be used in condenser more effectively than used in evaporator.
        4,300원
        3.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to investigate changes in the external thermal environment, following the application of evaporative cooling systems in buildings, in response to climate change. In order to verify changes in the external thermal environment, a T-test was performed on the microclimate, Thermal Comfort Index (TCI), and building surface temperature. Differences in microclimate, following the application of the evaporative cooling system in the building, were significant in terms of temperature and relative humidity. In particular, temperature decreased by more than 7% when the evaporative cooling system was applied. According to the results of the Thermal Comfort Index analysis, the Wet-Bulb Globe Temperature (WBGT) was below the limit of outdoor activities, indicating that outdoor activities were possible. The Universal Thermal Climate Index (UTCI) values were within the very strong heat stress range when the evaporative cooling system was not applied, When the system was applied, the UTCI values were within the strong heat stress range, indicating that they were lowered by one level. The building surface temperature decreased by ~10% or more when the evaporative cooling system was applied, compared to when it was not applied. Finally, the outside surface temperature of the building decreased by ~12% or more when the system was applied, compared to when it was not applied. We conclude that the energy saving effect of the building was significant.
        4.
        2009.09 KCI 등재 서비스 종료(열람 제한)
        본 논문의 목적은 열화상 비파괴 검사기법을 적용시 손상된 콘크리트 구조물의 표면온도를 증폭시키기 위해 사용되는 외부 열원의 효율성을 알아보기 위함이다. 원적외선램프와 할로겐램프의 적용성과 효율성을 서로 비교하였다. 이를 위해 전술한 두 개의 열원을 콘크리트의 내부공극과 FRP쉬트의 비부착 결함 시험체에 적용하였다. 본 연구결과, 원적외선램프가 할로겐램프보다 더 효율적인 것으로 파악되었다. 또한, 손상영역을 효과적으로 검출하기위해서 가우스 필터와 프리윗 마스크 화상처리기법을 혼합한 알고리즘을 제안하였다.