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        검색결과 130

        121.
        2002.04 KCI 등재 서비스 종료(열람 제한)
        도시하천 둔치내에 대규모로 자생하고 있는 식생으로 인한 흥수위 변화를 수리모형실험을 통해 검토하였다. 연구대상지역으로는 둔치내에 대나무군락이 밀생하고 있는 태화강을 선정하였다. 모형실험은 9.0km 하천구간을 수평축척 1/300, 연직축척 1/72으로 제작한 왜곡모형을 이용하였다. 현재 밀생하고 있는 대나무군락을 3개 지역으로 구분하여, 대나무군락의 평면적 위치와 대나무군락이 횡단면에서 차지하는 비율에 따른 홍수위 상승효과를 검토하였다. 분석결과 대나무
        122.
        2000.12 KCI 등재 서비스 종료(열람 제한)
        In this study, the distribution characteristics of volatile organic compounds (VOCs) were investigated on the seasonal basis across spring, summer, and fall during the year of 1998. According to this analysis, most VOC species investigated exhibited strong temporal trends. Over diurnal scale, there distribution characteristics were affected by seasonal factors strongly. While they showed high day/night ratio pattern during spring, the pattern was reversed during fall. When the seasonal mean values were compared between the two seasons, the spring values were systematically higher than their counterparts in most cases. In addition when our VOC measurement data were compared with those reported from elsewhere, we were able to conclude that the VOC levels in the study area are comparable to the level weakly impacted by the regional emissions of VOCs. Although our data are not sufficient enough to systematically explain the atmospheric distribution and behavior of VOCs, the findings of strong correlations among some of VOC species suggests strong need for investigating their interactions in the earth's atmosphere.
        124.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        지구온난화의 영향으로 배증 CO2 상태가 되는 약 60년 후의 한반도 평균강수량은 약 5-10%정도의 증가로 예측되고 있다. 그러나 수자원분야에서 평균강수량의 증가보다 더 중요한 것은 홍수 또는 가뭄과 같은 극치기상의 빈도 변화이다. 현재 국제적으로 이러한 극치기상의 빈번한 발생이 지구온난화의 한 증거로 받아들여지고 있기는 하나 그 양상이 어떻게 되리라고는 예측되고 있지 않다. 따라서 본 연구에서는 그러한 변화 양상을 예측해 보기 위한 방법론을 제시해
        125.
        1999.12 KCI 등재 서비스 종료(열람 제한)
        지구 온난화는 산업혁명이후 이미 시작되었으며 최근에 와서 그 정도가 심해지고 있다. CO2와 같은 온실기체의 증가를 가장 큰 원인으로 하는 지구 온난화의 영향이 아직 정량적으로 밝혀지고 있지만 대기순환모형(General Circulation Model: GCM)을 이용한 연구에서 이러한 온실기체의 증가가 지구의 평균온도를 상승시킨다고 밝히고 있다. 지구 온난화는 전지구적 물의 순환에도 영향을 미쳐 지구 곳곳의 강수패턴에 변화를 가져오는데 근래에 자주 발
        126.
        1998.08 KCI 등재 서비스 종료(열람 제한)
        최근 배수시스템의 설계시 임계지속기간의 개념을 도입하여 설계홍수량을 산정하고 있다. 그러나, 임계지속기간 산정시 설계강우분포의 선정은 명확한 기준없이 임의로 사용되고 있다. 따라서 본 연구에서는 중소규모의 도시화된 산본유역에 ILLUDAS 모형을 이용하여 다양한 강우분표형태가 임계지속기간에 미치는 영향에 대하여 분석하였다. 모형결과의 분석으로부터 강우분포형태(등분포, 삼각형분포, 사다리꼴분포, Huff 분포, IDF 를 이용한 중앙집중분포)는 임계지속기
        128.
        1997.02 KCI 등재 서비스 종료(열람 제한)
        Befor fertilization, mammalian oocytes undergo meiotic maturation, which consists of nuclear and cytoplasmic differentiation. In this study, changes of stores in mouse oocytes were examined during meiotic maturation and the role of in the regulation of the maturation was investigated by using monoclonal antibodies against smooth endoplasmic reticulum -ATPase(SERCA-ATPase) and calreticulin. Observations were made under epifluorescence microscope and/or confocal laser scanning microscope. In immature oocytes which did not resume meiotic maturation, SERCA-ATPases were mostly localized in the vicinity of the germinal vesicle and calreticulins were distributed evenly throughout the cytoplasm. In mature oocytes, SERCA-ATPases were observed throughout the cytoplasm, butwere absent from the nuclear region. In contrast, calreticulins were localized mostl in the cortex of the oocyte and were absent from the cytoplasm. However, bright fluoresence stainings were wbserved in the perimeiotic spindle region of mature oocyte when labeled with antibodies against calreticulin. These results indicate that mouse oocytes undergo distinct rearrangement of the localization of -ATPases and calreticulins during meiotic maturation. Thus it can be suggested that redistribution of the stores, as revealed by differential fluorescence stainings, is deeply involved in the regulatory mechanism of mammalian oocyte maturation.
        130.
        1981.03 KCI 등재 서비스 종료(열람 제한)
        Diurnal changes in leaf stomatal resistances were measured on leaf positions and both surfaces to investigate the stomatal response to irradiance in wheat, var. Chokwang and barley, var. Dongbori 1. Stomatal frequency and size were also determined to explain the control mechanism of gas exchanges in two species. The leaf diffusive resistances of two species decreased, as the sun rose, to minimum at 10 to 11 o'clock a.m. and increased gradually in the afternoon, even faster at sunset. As the adaxial irradiance increased, stomatal resistances decreased sensitively in the range of 30uEm-2 ㆍsec-1 to 150uEm-2 ㆍsec-1 quantum flux density. The stomatal opening of the abaxial surface began at lower irradiance and was completed earlier than the adaxial surface. The adaxial irradiances decreased in order of leaf position, flag, the 2nd, the 3rd leaf, and the stomatal resistances increased in the same order. Even under the same irradiance, the stomatal resistance of lower leaves were higher than those of upper leaves. The stomatal frequencies of lower leaves were less, but the stomatal size was greater than those of upper leaves. Consequently, the relative leaf area occupied by stomatal pores were constant among leaf positions in two species.
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