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        검색결과 6

        1.
        2023.05 구독 인증기관·개인회원 무료
        This study investigates the behavior of the thermal conductivity among material properties in order to develop a thermal evaluation methodology of spent fuel assembles in a transport cask. It is inefficient to model each element of the spent fuel assembly in detail, and it is generally calculated by modeling the effective thermal conductivity (ETC). The ETC model was developed to allow a much simpler representation of a spent fuel assembly within a fuel compartment by treating the entire spent fuel rod array and the surrounding fill gas within the confines of the compartment as a homogenous solid material. The fuel rod assembly and surrounding gas are modeled with an effective conductivity that is designed to yield an overall conduction heat transfer rate that is equivalent to the combined effect of local conduction and radiation heat transfer in a plane through the assembly. When this model is applied to the transport cask, it tends to predict the cladding peak temperature lower than the results of detailed model in which the fuel rod arrangement and shape of the fuel assembly are simulated. As for the tendency of the error, the model tended to under-predict when basket temperature was lower than a certain temperature, and over-predict when it was higher. The purpose of this study is to investigate the attenuation effect of the cladding peak temperature on the related variables when the ETC model is applied to the transport cask. In addition, based on the thermal characteristics of this model, a correction factor that can compensate for this attenuation effect is presented. This correction factor is obtained by finding the difference between a separate ETC homogeneous model and a separate detailed fuel model, rather than directly applying the ETC calculated from the detailed fuel model to the transport cask.
        2.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study simulated strong ground motion waveforms in the southern Korean Peninsula, based on the physical earthquake modeling of the Southern California Earthquake Center (SCEC) BroadBand Platform (BBP). Characteristics of intensity attenuation were investigated for M 6.0-7.0 events, incorporating the site effects. The SCEC BBP is software generates broadband (0-10 Hz) ground-motion waveforms for earthquake scenarios. Among five available modeling methods in the v16.5 platform, we used the Song Model. Approximately 50 earthquake scenarios each were simulated for M 6.0, 6.5, and 7.0 events. Representative metrics such as peak ground acceleration (PGA) and peak ground velocity (PGV) were obtained from the synthetic waveforms that were simulated before and after the consideration of site effects (VS30). They were then empirically converted to distribution of instrumental intensity. The intensity that considers the site effects is amplified at low rather than high VS30 zones.
        4,000원
        3.
        2020.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The stochastic point-source model has been widely used in generating artificial ground motions, which can be used to develop a ground motion prediction equation and to evaluate the seismic risk of structures. This model mainly consists of three different functions representing source, path, and site effects. The path effect is used to emulate decay in ground motion in accordance with distance from the source. In the stochastic point-source model, the path attenuation effect is taken into account by using the geometrical attenuation effect and the inelastic attenuation effect. The aim of this study is to develop accurate equations of ground motion attenuation in the Korean peninsula. In this study, attenuation was estimated and validated by using a stochastic point source model and observed ground motion recordings for the Korean peninsula.
        4,000원
        5.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        홍어 껍질 유래 콜라겐 펩타이드를 한외여과막을 이용하여 분자량의 크기를 1,000 Da 이하와 1,000 Da 이상으로 분리하고 그 효과를 비교하고자 하였다. 각각의 시료를 비만 유발 실험동물인 db/db mice에 체중당 200 mg의 콜라겐 펩타이드를 8주간 투여하였다. 본 연구의 결과는 콜라겐 펩타이드를 투여한 군에서 비만대조군에 비해 체중 증가량의 감소, 혈액 및 간조직의 활성산소 농도의 감소, 간조직의 산화적 스트레스가 완화된 것으로 나타났다. 또한 콜라겐 투여군에서 염증반응과 관련된 간조직의 핵전사인자(NF-κB) 및 효소(COX2, iNOS), 염증성 사이토카인(IL-6)발현이 비만대조군에 비해 유의적으로 감소하였다. 분자량의 크기에 따라 약간의 차이가 나타났지만, 전반적으로는 유의적이지 않았다. 따라서 홍어 콜라겐 펩타이드의 비만에 의해 유발된 염증반응이 억제되었는데, 이는 콜라겐의 산화적 스트레스 완화작용에 기인한 것으로 사료된다.
        4,000원
        6.
        2015.06 KCI 등재 서비스 종료(열람 제한)
        In this study, essential oils were extracted from the leaf of Chamaecyparis obtusa (CLEO), indigenous toKorea, CLEO constituents were analysed, and the effects of CLEO on airway hyperresponsiveness (AHR) and airwayinflammation (AI) were investigated in Ovalbumin (OVA)-induced asthma mouse model. Terpenoid components amongidentified CLEO constituents made up more than 80%. The CLEO-treated group in comparison to the control groupshowed reduced AHR, the decrease of eosinophil number in the bronchoalveolar lavage fluid (BALF), reduced specific anti-OVA IgE level in the serum, and a significant reduction in Th2 cytokines levels in the BALF with concentration. We con-cluded that CLEO have an alleviating effect on asthma-like symptoms such as AHR and AI. Further studies about antiasth-matic effect are necessary on the focus of single component of CLEO.