• 제목/요약/키워드: pebble

검색결과 187건 처리시간 0.029초

충주층군(忠州層群)과 서산층군(瑞山層群)의 비교연구(比較硏究) (Comparative Studies between Chungju and Seosan Groups)

  • 나기창;김형식;이동진;이상헌
    • 자원환경지질
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    • 제15권4호
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    • pp.177-188
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    • 1982
  • The Chungju and Seosan Groups have been known usually as Precambrian formations in Korea. But their relative and absolute ages have been controvericial problem in relation with other geologic system such as so-called Ogcheon and Yeoncheon Systems in Korea. This study has mainly focused on the corelation of the Chungju Group with the Seosan Group in their stratigraphy, structure, metamorphism, and iron ore deposits. In the process of study, the auther surveyed and reclassified the Chungju and Seosan Groups and corelated with Gyeonggi and Ogch cheon metamorphic belts and got some new data. The Chungju iron-bearing formations showing transtitional relation with the Gyeonggi Gneiss Complex and the Jangamri Formation consisting mainly of pebble bearing calcarious phyllite, should be seperated from the Gyemyeongsan formation which is mainly composed of metavolcanic rocks. The Jangamri Formation and the coaly phyllite, which can be corelated respectively with the Hwaggangri Formation and Changri Formation in Ogcheon Group, are repeated in the Gyemyeonsan and Munjuri Formations with the overturned anticlinal folding(F1). So the Chungju Group which was defined as an indipendant geologic unit from the Ogcheon Group should be limited only on the Chungju iron Formation. The Seosan Group can be classified stratigraphically such as Seosan Formation consisting of iron-bearing quartzite and mica schist, Daesan Formation overlying unconformably on the Seosan Formation and Gyeonggi Gneiss Complex. Taean Formation overlying unconformably on the Daesan Formation should be seperated from Seosan Group. There are many similarity in the stratigrphy, structure, and metamorphic facies between Chungju and Seosan Groups exept the metavolcanic rocks in the Gyemyeongsan and Munjuri Formations and the pebble bearing calcareous phyllite in the Jangamri Formation. The two Groups were deformed with two kinds of differant stages, the first shows $N30^{\circ}-40^{\circ}E$ trend of fold axis, the second $N70^{\circ}-80^{\circ}W$ respectively. The Seosan Formation, which is the lowest formation in Seosan Group and bearing the iron formation, was metamorphosed at 2500 m. y. before. These age is similar with the metamorphic age of Gyeonggi metamorphic belt and with the age of Algoman and Kenoran Orogenies which devide the Precambrian into Archean and Proterozoic Era. So the Seosan Formation, which is included in some migmatitic rocks of Gyeonggi Gneiss Complex, is the oldest formation in Korea and can be corelated with the Anshan Group which bears the oldest iron formation in China. The metamorphic facies of the Precambrian metamorphism in Seosan area is simillar with that of Chungju area, showing high temperature-low pressure amphibolite facies which is corelated with the Gyeonggi metamorphic belt, the oldest metamorphic belt in Korea ($650^{\circ}-680^{\circ}C$, 3.2-4.4 Kb). The high temperature intermediate pressure amphibolite facies in Seosan area with the low temperature-intermediate presure greenschist facies of Taean formation is corelated with that of Ogcheon Group ($590^{\circ}-640^{\circ}$ C, 5.2-6.3 Kb). The Chungju and Seosan iron formations were deposited in Archean, showing geochemical composition of Precambrian iron formations. The Chungju iron formation was mainly formed by the chemical precipitation, on the other hand, the Seosan iron formation was formed by alternated action of chemical and detrital depositions.

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4대강 보 건설에 따른 실지렁이류(Aquatic Oligochaeta) 서식분포 특성 비교 (Comparison of the habitat distribution characteristics of Aquatic Oligochaeta according to the construction of weirs in four major rivers in South Korea)

  • 왕주현;박형준;박정호;송행섭;김호준;박연정;최준길;이황구
    • 환경생물
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    • 제37권4호
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    • pp.607-617
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    • 2019
  • 본 연구는 4대강 보 설치에 따른 실지렁이류의 분포 특성을 파악하고자 연구를 실시하였다. 현지조사는 2018년 3월부터 10월까지 총 10회 실시하였다. 조사결과 총 18종 35,390 ind. m-2 개체가 출현하였다. Limnodrilus hoffmeisteri (77.1%)이 우점종, Branchiura sowerbyi (9.5%)이 아우점종으로 분석되었다. 건중량 분석결과 총 32.418 g m-2이 계측되었으며, 각 종별 건중량과 TOC 농도와의 상관 분석 결과 실지렁이, 아가미지렁이와 TOC 농도 간 음의 상관성을 갖는 것으로 나타났다. 실지렁이류와 물리적·이화학적 요인들 간의 다변량 상관분석 결과 퇴적토 깊이, Clay 비율, Silt 비율, Cobble 비율, Pebble 비율, pH, TOC 항목과 상관성을 갖는 것으로 분석되었다(p<0.05, p<0.01). 조사지역별 실지렁이류 개체수와 퇴적토 깊이 및 Clay의 비율과 비교·분석한 결과 퇴적토의 깊이와 Clay의 비율이 높을수록 개체수가 많은 것으로 나타났다. 조사시기에 따른 실지렁이류의 개체수, TOC 비교·분석결과 3월부터 10월까지 개체수는 감소하는 경향성을 나타냈으며, TOC는 증가하는 경향성을 갖는 것으로 분석되었다.

여수반도와 금오열도의 담수어류상 (Freshwater Fish Fauna of the Yeosu Peninsula and Geumo Islands, Korea)

  • 채병수;윤희남
    • 한국어류학회지
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    • 제19권3호
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    • pp.225-235
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    • 2007
  • 여수반도와 금오열도의 섬들 중 하천이 발달한 돌산도, 금오도, 개도의 39개 지점에서 2003년과 2005년에 걸쳐 담수어류상과 하천의 물리적 특성을 조사하였다. 조사지역 내의 하천들은 대부분 길이가 짧고 유폭이 좁았다. 주된 하상구성물질은 cobble, pebble, gravel이었으며, 하구에 인접한 곳은 주로 gravel과 sand로 되어 있었다. 39개의 조사지점 중 상류형인 Aa형이 18지점으로 가장 많았다. 담수어류상의 조사에서 모두 16과 39종 3,397개체가 채집되었는데, 생활형 구분으로는 일차담수어가 27종(69.2%), 주연성 어종 9종(23.1%)으로 대부분을 차지하였으며, 과별 어종구성은 Cyprinidae가 12종(30.8%), Gobiidae가 10종(25.6%)으로 많았다. 한반도 고유종은 Rhodeus uyekii 등 8종이 확인되었는데, 여수반도에서는 8종 모두 나타났고 금오도에서는 1종, 돌산도와 개도에서는 확인되지 않았다. 외래종은 Lepomis macrochirus 1종이 출현하였다. 각 지구별 우점종을 보면 여수반도에서는 Zacco temminckii, 돌산도에서는 Rhinogobius brunneus, 금오도에서는 Leucopsarion petersii, 개도에서는 Oryzias latipes가 우점종이었다. 군집분석의 결과 여수반도가 가장 다양하고 안정된 집단의 구조를 지니고 있었으며 섬의 크기가 작아질수록 다양도와 풍부도가 떨어졌다. Kichulchoia brevifasciata가 본 조사에서는 확인되지 않아 본 지역에서는 절멸하였을 가능성이 있다. Acanthorhodeus gracilis와 L. petersii는 본 지역에서는 처음으로 분포가 알려지게 되었다.

화분분석에 의한 한국 남동부 해안 산하동 일대의 MIS 5e 대비 해성단구 동정 (A Marine Terrace Correlated to MIS 5e on the Basis of Pollen Analysis at Sanha-Dong, Ulsan, Southeastern Coast of the Korean Peninsula)

  • 최성길;신현조;박지훈
    • 한국지형학회지
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    • 제24권3호
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    • pp.1-11
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    • 2017
  • The pollen analysis on the deposits of the lower marine terrace I of the estimated paleoshoreline height of 18m was performed in order to estimate the formation age of this terrace developed at the Sanha-dong coast, Ulsan, southeastern coast of the Korean peninsula. The pollen assemblage of the peat layer of SH-1 pollen zone (Quercus-Ulmus/Zelkova zone), lying directly on the marine rounded pebble layer of this terrace, shows that the climatic environment of the deposition period of SH-1 pollen zone was almost similar to that of the Postglacial climatic optimum period, but slightly cooler than that of the late warm stage of Last Interglacial(MIS 5a) in the eastern coast of Korea. This heightens the possibility that the deposition period of the marine rounded pebble layer which was covered by the above SH-1 peat layer is the MIS 5e which has been estimated by a previous study of the sedimentary facies of this terrace deposits (Choi, 2016). The pollen assemblage of SH-2 pollen zone (Pinus-Quercus zone) shows that the climate of this period was almost similar to that of the late Postglacial, but slightly cooler than that of the period of SH-1 pollen zone. This means that the climate around the Sanha-dong was still warmer in the deposition period of the peat layer of SH-2 pollen zone. Thus, the peat layer of SH-2 pollen zone was considered to have been deposited during the period from the early regression stage of the MIS 5d which is the estimated final stage in the deposition period of the above peat layer of SH-1 pollen zone to any stage in which the warmer environment of MIS 5 has still lasted. The humic silt layer of SH-3 pollen zone (Pinus-Ulmus/Zelkova-Abies zone) is assumed to have been deposited during the interstadial of the Last Glacial (MIS 3).

HTGR PROJECTS IN CHINA

  • Wu, Zongxin;Yu, Suyuan
    • Nuclear Engineering and Technology
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    • 제39권2호
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    • pp.103-110
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    • 2007
  • The High Temperature Gas-cooled Reactor (HTGR) possesses inherent safety features and is recognized as a representative advanced nuclear system for the future. Based on the success of the HTR-10, the long-time operation test and safety demonstration tests were carried out. The long-time operation test verifies that the operation procedure and control method are appropriate for the HTR-10 and the safety demonstration test shows that the HTR-10 possesses inherent safety features with a great margin. Meanwhile, two new projects have been recently launched to further develop HTGR technology. One is a prototype modular plant, denoted as HTR-PM, to demonstrate the commercial capability of the HTGR power plant. The HTR-PM is designed as $2{\times}250$ MWt, pebble bed core with a steam turbine generator that serves as an energy conversion system. The other is a gas turbine generator system coupled with the HTR-10, denoted as HTR-10GT, built to demonstrate the feasibility of the HTGR gas turbine technology. The gas turbine generator system is designed in a single shaft configuration supported by active magnetic bearings (AMB). The HTR-10GT project is now in the stage of engineering design and component fabrication. R&D on the helium turbocompressor, a key component, and the key technology of AMB are in progress.

B2S궤도시스템의 초기 시설 투입비용 분석 (Initial Investment Cost Analysis of Facilities of B2S Track System)

  • 김효산;민준호;유재광;이달재
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2011년도 춘계학술대회 논문집
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    • pp.733-739
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    • 2011
  • B2S(Ballasted track To Slab track) that is track system has been first developed in 2004 with foundation of rich experience and know-how of subway track upkeep and mending of facilities in 36 years to improve an existence pebble track at a concrete track. 'B2S' is admitted technology through patent registration in the domestic and Europe and it's made by a factory and put together at field, so it's able to construct precisely and to reduce a construction period. In addition, safety, the ecological balance and durability are excellent, and walking, cleaning, etc. has the advantage of easy maintenance. 'B2S' is currently laying 27.7km at Seoulmetro as of end of 2010 standard, but it'll be expected to be applied to a domestic Metro more from now on. It is possible to classify the total cost resolution structure of B2S system by R&D cost, test production and experiment cost, the initial facility cost, maintenance cost, disposal cost. In this research, it seems useful for selection evaluation which considered the life cycle cost or economics of the concrete track structure by analyzing an initial cost of facilities.

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용인시 석성산의 자연환경 보전 (Nature Conservation of Mt. Seokseong in Yongin-si)

  • 이웅빈
    • 환경생물
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    • 제24권3호
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    • pp.294-299
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    • 2006
  • 용인시 석성산은 북위 $37^{\circ}15'15'{\sim}37^{\circ}17'00'$, 동경 $127^{\circ}09'30'{\sim}127^{\circ}11'00'$에 걸쳐 위치한다. 군집분석 결과 B지역에는 170종류의 관속식물이 생육하고 있어 조사지역 가운데 가장 식생이 풍부한 것으로 조사되었고, C지역은 140종류의 관속식물을 갖고 있어 다음으로 식생이 풍부하다. 그러나 관속식물의 유사도 지수는 B지역과 D지역이 53.7%로 가장 높은 것으로 나타났다. 생태공원을 만들기 위하여 등산로, 삼림욕장, 수서생물 못, 자갈길, 식물관찰로 등 테마공원 조성이 필요하다. 한편 이 지역의 생태적 고립화를 막기 위하여 멱조고개와 용인정신병원 앞 도로 위로 생태다리를 건설하여야 할 것으로 판단된다.

코이어블록(Coir-Blocks)을 이용한 절토사면의 경관개선 및 비점오염원 관리에 관한 연구 (A Study on Landscape Improvement of Cut-Slopes and Management of Non-Point Pollution Using Coir-Blocks)

  • 이관준;박율진
    • 한국환경복원기술학회지
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    • 제18권5호
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    • pp.27-36
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    • 2015
  • This study was conducted to grasp the effect of afforestation of cut slope using coir blocks on the improvement of scenery and the management of non point pollution source. Total four experimental tanks such as general soil slope, coir blocks, installation slope, slope refilling the inside of coir blocks slope with pebble, slope refilling the inside of coir blocks with soil and plant were installed, pollution source water was supplied and the possibility of reduction management of non point pollution source was analyzed at four items of COD, SS, T-N, T-P and main results drawn from this study are as follows. In conclusion, biodegradable materials like coir blocks and soil and plant layers are judged to be helpful in reduction management of non point pollution source inflowing to water space from land area. Thus, the reduction of non point pollution source occurring at land area is thought to be fully controlled at the cut slope, the space prior to inflowing to water ecological space like a stream or a swamp area.

저서성 대형무척추동물 군집의 피해 및 회복 규명을 위한 수리실험 계획 (Experimental Design for Damage and Recovery of Benthic Macroinvertebrate Communities)

  • 정순혁;김진홍
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2009년도 학술발표회 초록집
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    • pp.2122-2126
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    • 2009
  • 최근 나날이 강도를 더해가는 이상기후로 인하여 집중 호우의 빈발과 홍수피해가 급증함으로써 하천생태계의 서식처가 파괴되고 저서성 대형무척추동물과 같은 생태구성원의 일시적인 소멸에 의해 하천생태계의 유지가 어려워지고 있다. 본 연구에서는 흐름의 소류력에 따른 저서성 대형무척추동물 군집의 피해 및 회복 양상을 규명하기 위한 수리실험을 계획하였다. 실험수로는 400(W)${\times}$400(H)${\times}$12000(L)mm의 직사각형 단면이며, 철제틀과 투명유리로 되어있다. 실험수로는 유기물질을 제거한 cobble과 pebble로 하상을 구성하였으며, 다양한 유속의 변화에 따른 하상구성 파괴를 막기 위해 투명 플라스틱망을 이용하였다. 또한 빛에 의한 이상행동을 고려하여 직접적인 햇볕을 차단하고 자연하천과 유사한 실험 조건을 위해 인근 안성천의 원수를 이용하였다. 실험 대상종은 붙는 무리의 대표적인 동물인 두점하루살이와, 헤엄치는 무리의 두갈래하루살이를 이용하였고, 서식무리별 선호유속 및 한계유속과 피해유속을 규명하고자 계획하였다. 이와 같은 실험수로 조성의 실험 기법은 향후 인공하천 및 복원하천 조성 시 서식처 개선에 대한 생태학적 복원자료로 활용할 수 있다.

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강원감영의 공간구성과 구성요소의 건축적 특징에 관한 연구 (A Stud on the Space Organization and Composition Elements in Gangwon Gamyoung)

  • 최장순
    • 한국농촌건축학회논문집
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    • 제7권2호
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    • pp.31-47
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    • 2005
  • This study is to inspect and analyse the historical background, spacial organization and architectural features about the traditional government office building of Gangwon Gamyoung(the supreme local government office of Gangwondo in Chosun dynasty). The results are as follows. - Gangwon Gamyoung was located at the center of Gangwondo in consideration of distance to each small local office. And also it was located in consideration of geographical connection between Hanseong(today's Seoul). - The spatial organization of Gamyoung was divided into the three parts of entrance space, government office building space and backyard space. The entrance space was composed of three gates(Pojungru-Jungsammun-Naesammun). The government office building Space was consisted of business and living building as center of Sunhwadang(the main office building). And the backyard space was composed of Yonji(pond), Jungja(bower), and so on - The way to enter the space of Gamyoung follows the order from Pojungru(the first & outer main gate with a bower), Jungsammun(the second & intermediate gate), Naesammun(the third & inner gate) to Sunhwadang at last. - There were a beautiful Yonji(pond) which to be rectangular type and to have a round island with Bongraegak(bower) at Gamyoung backyard, the drain conduit and pedestrian road covered with pebble in the ground.

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