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        검색결과 3

        1.
        2024.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 단기간의 UV-A 조사가 시금치(Spinacia oleracea L.)의 생장과 생리활성물질에 미치는 영향을 평가 하였다. 시금치 묘는 200μmol·m-2·s-1 PPFD, white LED, 광 주기 12시간, 온도 20°C, 상대습도 70%, 이산화탄소 농도 500μmol·mol-1의 수직농장 모듈에서 재배되었다. 파종 후 5 주된 묘는 7일 동안 20W·m-2와 40W·m-2의 두 가지 에너지 수 준에서 연속적으로 UV-A(피크파장: 385nm) 조사한 후 생육 특성, 광합성 파라미터, 이미지 형광, 총 페놀 함량, 항산화도, 그리고 총 플라보노이드 함량을 분석하였다. 결과적으로, UV-A20W 처리는 시금치의 생체중과 건물중을 증가시켰다. 하지만, UV-A 처리구와 대조구 사이의 광합성 파라미터에는 유의한 차이가 나타나지 않았다. 광계Ⅱ의 최대양자수율 (Fv/Fm)은 모든 UV-A 처리에서 7일동안 지속적으로 감소했 다. 또한, UV-A20W 처리에서 식물체당 총 페놀 함량과 항산화 도는 처리 7일째 증대되었으며, 총 플라보노이드 함량은 처리 5일째부터 유의적으로 증가하였다. 이러한 결과는 UV-A LED 보광이 수직농장과 같은 폐쇄형 식물 생산 시스템에서 재배되는 시금치의 생장과 품질을 향상시킬 수 있음을 시사 한다.
        4,000원
        2.
        2021.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to several seismic design standards, a ground motion time history should be selected similar to the design response spectrum, or a ground motion time history should be modified by matching procedure to the design response spectrum through the time-domain method. For the response spectrum matching procedure, appropriate seed ground motions need to be selected to maintain recorded earthquake accelerogram characteristics. However, there are no specific criteria for selecting the seed ground motions for applying this methodology. In this study, the characteristics of ground motion time histories between seed motions and spectral matched motions were compared. Intensity measures used in the design were compared, and their change by spectral matching procedure was quantified. In addition, the seed ground motion sets were determined according to the response spectrum shape, and these sets analyzed the response of nonlinear and equivalent linear single degrees of freedom systems to present the seed motion selection conditions for spectral matching. As a result, several considerations for applying the time domain spectral matching method were presented.
        4,000원
        3.
        2021.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The design response spectrum presented in the seismic design standard reflects the characteristics of the tectonic environment at a site. However, since the design response spectrum does not represent the ground motion with a specific earthquake magnitude or distance, input ground motions for response history analysis need to be selected reasonably. It is appropriate to use observed ground motions recorded in Korea for the seismic design. However, recently recorded ground motions in the Gyeongju (2016) or Pohang (2017) earthquakes are not compatible with the design response spectrum. Therefore, it is necessary to convert the recorded ground motion in Korea to a model similar to the design response spectrum. In this study, several approaches to adjust the spectral acceleration level at each period range were tested. These are the intrinsic and scattering attenuation considering the earthquake environment, magnitude, distance change by the green function method, and a rupture propagation direction's directivity effect. Using these variables, the amplification ratio for the representative natural period was regressed. Finally, the optimum condition compatible with the design response spectrum was suggested, and the validation was performed by converting the recorded ground motion.
        4,000원