• 제목/요약/키워드: sea sand

검색결과 624건 처리시간 0.028초

Application of Remote Sensing and GIS technology for monitoring coastal changes in estuary area of the Red river system, Vietnam

  • Lan, Pham Thi;Son, Tong Si;Gunasekara, Kavinda;Nhan, Nguyen Thi;Hien, La Phu
    • 한국측량학회지
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    • 제31권6_2호
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    • pp.529-538
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    • 2013
  • Coastline is the most dynamic part of seascape since its shape is affected by various factors. Coastal zone is an area with immense geological, geomorphological and ecological interest. Monitoring coastal change is very important for safe navigation, coastal resource management. This paper shows a result of monitoring coastal morphological changes using Remote Sensing and GIS. Study was carried out to obtain intensity of erosion, deposition and sand bar movement in the Red River Delta. Satellite images of ALOS/AVNIR-2 and Landsat were used for the monitoring of coastal morphological changes over the period of 1975 to 2009. Band rationing and threshold technique was used for the coastline extraction. Tidal levels at the time of image acquisition varied from -0.89m to 2.87m. Therefore, coastline from another image at a different tidal level in the same year was considered to get the corrected coastline by interpolation technique. A series of points were generated along the coastal line from 1975 image and were established as reference points to see the change in later periods. The changes were measured in Euclidean distances from these reference points. Positive values represented deposition to the sea and negative values are erosion. The result showed that the Red river delta area expanded to the sea 3500m in Red river mouth, and 2873m in Thai Binh river mouth from 1975 to 2009. The erosion process occurred continuously from 1975 up to now with the average magnitude 23.77m/year from 1975 to 1989 and 7.85m/year from 2001 to 2009 in Giao Thuy area. From 1975 to 2009, total 1095.2ha of settlement area was eroded by sea. On the other hand, land expanded to the sea in 4786.24ha of mangrove and 1673.98ha of aquaculture.

서해안 준설토의 역학적 특성 및 시간경과에 따른 강도 특성에 관한 연구 (A Study on the Mechanical Characteristic and Shear Strength haracteristic on Elapsed Time of the Western Sea Dredged Soils)

  • 김홍택;한연진;유완동
    • 한국지반환경공학회 논문집
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    • 제14권2호
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    • pp.31-41
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    • 2013
  • 서해안 지역의 준설토는 실트 또는 세립모래 성분이 많은 특성으로 인해 성토재로 직접 사용되는 사례가 증가하고 있으나, 준설토를 성토재로써 활용하는 연구에 대해서는 미흡하다. 이에 본 연구에서는 서해안 지역의 준설토를 성토재료의 활용성을 확인 하고자 하였다. 우선적으로 피에조콘 관입시험을 통해서 준설 지반의 구성성분을 확인함으로써 성토재의 활용 가능성을 우선적으로 확인하였다. 준설토에 대한 침강 및 자중압밀시험을 시행하여 준설토의 특성을 평가하는 동시에 침강 및 자중압밀이 완료된 시료에 대해서 다짐시험 및 직접전단시험을 시행함으로써 준설토의 준설완료 시점의 특성을 확인하였다. 아울러 침강 및 자중압밀이 완료 된 시료를 자연배수시킴으로써 시간이 경과됨에 따라서 준설토가 보이는 역학적 특성을 확인하고자 하였다. 실트, 실트질 모래 및 모래성분이 다량 포함되고 있는 서해안 지역의 준설토는 자연배수 시간이 경과함에 따라서 단위중량과 전단강도가 증가되는 특성 을 보이는 것으로 평가되었다.

녹조식물 가시파래, Enteromorpha prolifera의 양식연구 (A Study on the Cultivation of Enteromorpha prolifera(Muller) J.Agardh, Chlorophyta in Korea)

  • 윤장택;조용철;공용근
    • 한국양식학회지
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    • 제16권1호
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    • pp.44-50
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    • 2003
  • 가시파래의 자연 서식지에서 자연채묘 방법과 실내에서 포자방출에 의한 인공종묘생산 기술을 개발하고, 양성시험에 의한 완전한 양식방법을 개발하여 대량생산 가능성을 조사하였다. 가시파래 자연채묘는 자연 서식지의 사니질로 조성된 해역이 적합하였으며, 하계의 착생밀도는 채묘틀이 지면에서 20cm 높이에 시설하는 것이 높았고, 추계에는 40cm 높이에 시설하는 것이 효과적이었다. 가시파래 인공종묘 생산은 성숙한 모조를 12~24시간 음건하여 포자를 방출하고, 포자액이 들어있는 수조에 채묘망을 넣고 24시간 암흑처리하면 포자 착생률이 높게 나타났다. 가시파래 양성은 수심이 낮고 저질이 니질 또는 사니질로 조성된 해역은 지주식으로 시설하며, 수심이 깊고 유속이 빠른 해역은 부류식으로 시설하는 것이 좋았다. 양성장소는 영양염이 풍부하고 파랑에 의한 엽체의 탈락과 시설물 파손이 적은 해역이 양호하였으며, 광합성률을 높이기 위하여 표층노출식으로 시설하는 것이 생산량이 많았다.

Penicillium Diversity from Intertidal Zone in Korea

  • Park, Myung Soo;Lee, Seobihn;Oh, Seung-Yoon;Lim, Young Woon
    • 한국균학회소식:학술대회논문집
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    • 한국균학회 2016년도 춘계학술대회 및 임시총회
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    • pp.11-11
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    • 2016
  • Penicillium species are commonly isolated from various outdoor and indoor environments, including marine environments such as sponges, algae and sand. Penicillium is especially important because numerous bioactive compounds have been isolated. Penicillium was the most common species in intertidal zone in Korea, however the diversity and ecological roles of Penicillium in intertidal zone are not clarified. We explored diversity and ecological roles of marine-derived Penicillium from tidal flat and sea sand in Korea. The diversity of marine-derived Penicillium from Korea was investigated using both culture-dependent and culture-independent approach by ${\beta}$-tubulin sequence. In addition, we evaluated optimal temperature, halo-tolerance, and enzyme activity of Penicillium strains, such as extracellular alginase, endoglucanase, ${\beta}$-glucosidase, and protease. For culture-dependent approach, a total of 182 strains of 62 Penicillium species were isolated, with 53 species being identified. The most common species was Penicillium oxalicum, followed by P. crustosum, P. brasilianum, P. koreense, and P. griseofulvum. Species richness and composition were not significantly different by season, substrates, and seaside. For culture-independent approach using Illumina sequencing, 73 OTUSs were detected. The most frequently observed species was P. antarcticum, followed by P. koreense, P. crustosum, and P. brevicompactum. Diversity of Penicillium was higher during winter season than during summer season and in western sea than in southern sea, respectively. Community structure was significantly different by season and sea side. 52 species were detected by both methods. Unique species were isolated from each of methods - 10 from culture methods and 21 from Illumina sequencing. Furthermore, salinity adaption of the Penicillium varied depending on species. Many Penicillium species showed endoglucanase, ${\beta}$-glucosidase, and protease activity. Some species including P. paneum and P. javanicum degraded the polycyclic aromatic hydrocarbons. Thus, our results demonstrate that intertidal zone in Korea harbors diverse Penicillium community and marine-derived Penicillium play important ecological roles as decomposers of organic material in marine environments.

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한국 서해안 곰소만 조간대의 제 4기 층서와 해수면 변화 (Late Quaternary stratigraphy and sea-level change in the tidal flat of Gomso Bay, West Coast of Korea)

  • 장진호;박용안
    • 한국해양학회지:바다
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    • 제1권2호
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    • pp.59-72
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    • 1996
  • 한반도 서해안 곰소만 조간대의 제 4기 층서는 최소한 2개의 부정합면을 경계로 하여 하부로부터 기반암, 선현세 산화대층(혹은 풍화토), 현세 조간대층의 순서로 배열된다. 선현세의 산화대층은 황갈색의 반고화된 이질 퇴적층으로서 식물 뿌리와 식물 조각들이 산재하고, 수평 및 수직 방향의 미세한 틈(crack)들이 존재하며, 해양성 패각과 미고생물 화석은 전혀 존재하지 않는다. 이 산화대층은 12,000년 B.P.이전의 아빙기(stadial) 시기에 해안 육지의 지형적 저지(소분지)에서 퇴적된 것으로 추정된다. 현세의 조간대층은 하부의 이질 퇴적상(상부 조간대층) 과 상부의 사질 퇴적상(중부 및 하부 조간대층)으로 구성된 상향조립의 해침층 (transgressive succession)으로서 현세의 해수면 상승을 반영한다. 해수면 지시에 적합한 물질의 $^{14}$ C-연령과 심도(depth)의 상관관계에 기초하여 현세의 해수 면 변화를 추적한 결과, 한반도 서해의 해수면(relative sea-level 혹은 local sea- level)은 현재의 평균 해수면을 기준으로 7,000년 B.P.에 6.5 m 아래, 4,000년 B.P. 에 3 m 아래, 그리고 2,000년 B.P.에는 2.5 m 아래에 위치하였고, 현세 동안 큰 범위의 상승 및 하강 변화를 보인 증거는 찾을 수 없었다.

Study on the possibility of the aerosol and/or Yellow dust detection in the atmosphere by Ocean Scanning Multispectral Imager(OSMI)

  • Chung, Hyo-Sang;Park, Hye-Sook;Bag, Gyun-Myeong;Yoon, Hong-Joo;Jang, Kwang-Mi
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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    • pp.409-414
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    • 1998
  • To examine the detectability of the aerosol and/or Yellow dust from China crossing over the Yellow sea, three works carried out as follows , Firstly, a comparison was made of the visible(VIS), water vapor(WV), and Infrared(IR) images of the GMS-5 and NOAA/AVHRR on the cases of yellow sand event over Korea. Secondly, the spectral radiance and reflectance(%) was observed during the yellow sand phenomena on April, 1998 in Seoul using the GER-2600 spectroradiometer, which observed the reflected radiance from 350 to 2500 nm in the atmosphere. We selected the optimum wavelength for detecting of the yellow sand from this observation, considering the effects of atmospheric absorption. Finally, the atmospheric radiance emerging from the LOWTRAN-7 radiative transfer model was simulated with and without yellow sand, where we used the estimated aerosol column optical depth ($\tau$ 673 nm) in the Meteorological Research Institute and the d'Almeida's statistical atmospheric aerosol radiative characteristics. The image analysis showed that it was very difficult to detect the yellow sand region only by the image processing because the albedo characteristics of the sand vary irregularly according to the density, size, components and depth of the yellow sand clouds. We found that the 670-680 nm band was useful to simulate aerosol characteristics considering the absorption band from the radiance observation. We are now processing the simulation of atmospheric radiance distribution in the range of 400-900 nm. The purpose of this study is to present the preliminary results of the aerosol and/or Yellow dust detectability using the Ocean Scanning Multispectral Imager(OSMI), which will be mounted on KOMPSAT-1 as the ocean color monitoring sensor with the range of 400-900 nm wavelength.

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해안림의 방풍 효과에 영향을 미치는 설치 파라미터 분석 (INSTALLATION PARAMETERS EFFECTING ON THE WIND PROOF OF A COASTAL FOREST)

  • 신종현;장세명;박기형;윤호중
    • 한국전산유체공학회지
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    • 제20권2호
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    • pp.52-60
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    • 2015
  • The objective of this research lies in the effect of installation parameters influencing on the wind proof performance of the coastal forest for damage prevention. The dissipation ratio of incident wind power is developed as an assessment index to make a lumped parameter study possible. From the real field data of East, West, and South Sea bounded on the Korean peninsula, single and double storied forests were modeled in three-dimensional shape with computer aided design, and so was done the artificial structures such as wind break, sand accumulating fence, and sand dune, etc With a commercial code ANSYS-CFX, the computational result from the comparison of dissipation ratio between single and double storied forest shows the effect of composition, and also the installation effect is investigated for artificial structures with optimal dimension of distance.

잔골재 특성에 따른 콘크리트 건조수축 모델링에 관한 연구 (A Study on Modelling for Prediction of Concrete Drying Shrinkage according to Properties of Aggregate)

  • 박도경;양극영
    • 한국건축시공학회지
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    • 제6권1호
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    • pp.73-77
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    • 2006
  • Drying Shrinkage has much complexity as it has relations with both internal elements of concrete and external factors. Therefore, experiments on Concrete Drying Shrinkage are carried out in this study under simplified circumstances applying temperature & Humidity test chamber which enables constant temperature and humidify. Comparative analyses have been made respectively according to the consequences aiming at modelling for prediction of Concrete Drying Shrinkage and making out measures to reduce it. As a result Strain Rate of Drying Shrinkage of concrete was measured to increase by average $10{\times}10^{-5}$ in proportion to additional 4% increase in fine aggregate ratio, when water/cement ratio constant. Strain Rate of Drying Shrinkage in pit sand concrete increased 20% higher than measured when in river sand under the condition of 90-day material age. 6. Strain Rate of Drying Shrinkage in sea sand concrete increased $10%{\sim}15%$ higher than measured when in river sand. The results of prediction of Rate of Drying Shrinkage by Response Surface Analysis are as fellows. The coefficient of correlation of Drying Shrinkage in concrete was over 90%.