• 제목/요약/키워드: pebble

검색결과 189건 처리시간 0.029초

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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Early Stage of Algal Succession on Artificial Reefs at Muronohana, Ikata, Japan

  • Choi Chang Geun;Takayama Hiroshi;Segawa Shigeru;Ohno Masao;Sohn Chul Hyun
    • Fisheries and Aquatic Sciences
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    • 제3권1호
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    • pp.1-7
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    • 2000
  • Different substrata fixed as the roof (for shadow) on artificial iron reef had been developed as a tool for valuable fishery resources. The experiment was set up on a sandy bottom substratum at 8m depth in Muronohana, Ikata, Japan. Within one month of placement of the plates, diatoms dominated the experimental plates with a coverage of $100\%$ approximately. Enteromorpha intestinalis and Colpomenia sinuosa dominated within three months after the placement. E. intestinalis coverage on substrata was estimated $7\%$ on the plate shaped iron bar, $12-14\%$ on concrete plates, $18\%$ on the plate fixed pebble, $61\%$ on the plate to accumulated wood, and 80-100% on the steel materials plate. Whereas after four months of placement, C. sinuosa coverage on plates became $1-36\%$ on different plates, and $100\%$ on the plate to accumulated wood. The differences in E. intestinalis and C. sinuosa colonization on the different substrata were probably due to variations in their surface roughness influencing the settlement of zoospores, and thus gametophyte. development. After five months of placement, the above two species slowly disappeared.

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화순천의 퇴적환경 및 퇴적물과 하천수의 지구화학적 특성 (Sedimentary Environments, Geochemical Characteristics of Sediments and River waters, Hwasun-cheon)

  • 오강호;고영구;김주용;김해경
    • 한국환경과학회지
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    • 제11권9호
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    • pp.881-895
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    • 2002
  • Sediments and river waters form the channel of Hwasun-cheon were studied in sedimentological size and geochemical analyses of metallic elements for the purposes of identification of depositional environments and geochemical characteristics. The sizes of sediments are assigned to pebble to coarse sand in mean size and polymodal in distribution. And the sediments are poorly to very poorly sorted and positively skewed. According to the grain size distributions of the sediments, the Hwasun-cheon belongs to gravel-bed river on the basis of the grain size distribution of the sediments. The behaviors of metallic elements in the sediments mainly depend on not grain size distribution but the geology connected with geomorphological reliefs near the stream. Contamination indices(CI) of Zn, Cu and Pb are 2.83 to 6.96 with average 4.31 in the sediments. Hwasun-cheon is assigned to general stream type in accordance with water quality of physical factors and chemical characteristics by Piper's diagram. Though meaningful values of BOD, T-N, T-P were locally depicted near Masan-ri, Hwasun-eup and Jiseok-cheon areas, artificial metal concentration do not represent in the most area of the stream. Sediments and river water are considered that the relatively more or less high metallic contents in the stream are originated from coal mine and urban area.

섬진강에 서식하는 왕종개 Iksookimia longicorpa (Cobitidae)의 생태 (Ecology of Iksookimia longicorpa (Cobitidae) in the Seomjin River, Korea)

  • 김익수;고명훈
    • 한국어류학회지
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    • 제17권2호
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    • pp.112-122
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    • 2005
  • Iksookimia longicorpa was investigated in the upper part of the Seomjin River in Korea from 2003 to 2004. It inhabited pebble and cobble bottoms with water-current velocities of 10~30 cm/sec and depths of 30~100 cm. This species is active during daylight hours from March to October but hibernated in the river bottoms in the winter season. The sex ratio of female to male was 1 : 0.65, and the female was 20~40 mm larger than the male. Female length frequencies in this population indicated that the 65~90 mm group is 1+years old, the 90~110 mm group is 2+ years old, and the 110~130 mm group is 3+ years old. The males developed a secondary sexual character, the lamina circularis at the base of their pectoral fin, after 13~14 months. The spawning season was from early to middle June with water temperatures of $20{\sim}24^{\circ}C$ individuals became sexually mature after the age of 2 years. The average number of eggs in the ovaries was $2,402{\pm}944$. Stomach contents were mainly Chironomidae, Ephemeroptera, Arcellidae and Algae. The feeding rate was highest in April and September; they did not fed in the winter.

현장실험을 통한 수생식물의 수질정화 효과에 관한 연구 (A Study on the Water Quality Purification Effect of Aquatic Plants in field work)

  • 이종성;김기남
    • 한국환경과학회지
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    • 제14권10호
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    • pp.937-944
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    • 2005
  • Presently, aquatic plants are used for the water purification in inland water. This study was carried out to investigate the water purification effect of aquatic plants, Oenanthe javanica and Typha angustata, The experiment was conducted in outdoor flowing water was conducted for ten days, Water quality was measured in terms of water temperature, COD(chemical oxygen demand), SS(suspended solids), Total N, Total P. The results of field experimentation showed that hydraulic retention time was the earliest in July and August 2003, and there were not any particular changes of monthly water temperature in inflow water and outflow water. As we look at the changes taken place in inflow water and outflow water throughout the whole experiment period, the change of water quality in summer was salient, especially SS removal ratio showed distinguished change as $25\%$, when the pebble filter and aquatic were attached to it. The removal rate of COD, total N total P were $14,7\%,\;8\%\;and\;9\%$, respectively. In relating the length of water extension to the change in water quality, the water quality tended to get lower generally in proportion to hydraulic retention time.

다카다 겐조(Kenzo Takada)의 작품에 관한 연구 (A Study on the Kenzo Takada's Works)

  • 정연자
    • 복식
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    • 제21권
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    • pp.207-218
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    • 1993
  • The desire of our contempories who wish to recover humanities fading away and get back recover humanities fading away and get back to the nature is emerging as a main theme of the fashion today the decade of facing 21st century. The prevalence of naturalness-ecology ru-ral peasant look-and ethnic look shows the tendency mentioned above. Kenzo Takada' works which exhibit this naturalness and ethnic look were picked and investigated. The objective of this research is to study the beauty of form and internal and investi-gate in what form the naturaless and Ethnic look in Kenzo's work. The result were as followings : <1> Draped form are mainly used as form and they are made neglecting the body line by straight-cut and provide the wearer ease and freedom of movements <2> As for the color fantastic original colors (red, blue, etc) and natural colors are used. And Strong color contrast is seen. In ethnic look original colors(red, blue, etc.) natural colors and ethnic colors are used. <3> As for the fabric Cotton neat skilk and wool etc are used mainly and use of such natural fibers represents the return to the natural well. <4> As for ornament natural things-straw hat flower feather pebble, shell-are used and exhibit natural feelings strongly. For the ethnic look ornaments representing each country's ethnic atmos-phere by hat scarf and neckcloth made of natural fibers. <5> As for naturalness Flower deer butter-fly leopard and plant etc, are used as motif. As for ethnic look flower geometric motif are used.

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전주천 참종개 Cobitis Koreensis 의 생태 (Ecological studies of Cobitid Fish, Cobitis koreensis in Jeonju-cheon Creek, Jeonrabug-do province, Korea)

  • Ik Soo Kim
    • The Korean Journal of Ecology
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    • 제2권1호
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    • pp.9-14
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    • 1978
  • The study was made to expand the knowledge of the ecology of Cobitis koreensis which is very common in the upper and middle part of rivers in western part of Korea. A number of C. koreensis are found in the creek of Jeonju-cheon located at Segjang-ri, Wanju-gun, Jeonrabug-do Province. The area studied has pebble bottoms. The flow velocity of the river ranges from 20cm to 40cm per second under normal conditions. The sex ratio of male to female was 1:1.34 and the female was 10~25mm larger than the male in total length. Length-frequencies in this population indicate that 20~40 mm fish group is underyearling, 40~60mm is a yearling, and 60~85mm is two-year-old. And the fish longer than 90mm in total length is regarded as being over three-year-old. Based on the ratio of gonadal weight to body weight, spawning in this species began in April and expanded well into June with water temperature 20~26。C, and the individuals became sexually mature over the two-year-old. The number of the eggs was counted from ten matured female fishes. The mean number of eggs in seven 72.6~81.4mm fishes was 908 (595-1, 229) and that of the rest three 86.0~89.0mm was 1, 674 (1, 337-2, 023). The contents of stomach in the other fifteen specimens captured in September 1977 were investigated. While the younger fed almost on the algae, the foods in the adult were largely aquatic insects.

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Cement Prefabricated Piped Making and Its Application on Agriculture Irrigation

  • Meng, Qingchang;Sun, Qingyi;Dang, Yongliang
    • 한국농업기계학회:학술대회논문집
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    • 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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    • pp.212-218
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    • 1996
  • The concrete pipe used to distribute irrigation water to the right place now available is commonly made up of cement , sand, earth, pebble, etc. These materials with right ratio and right amount of water were mixed and squeezed through the pipe-making machine called vertical squeezed pipe-making machine, and then a cement prefabricated pipe is produced . This kinds of pipe has been expanding by leaps and bounds. Being little cement contents and low cost, the length of pipe is 1.0m or so with weight of 50kg, which is easy to be made and to be transported. The demolish pressure of it is 0.2 MPa or so, which meets the needs of agriculture irrigation . The buried pipe irrigation system, has been popularized in Jining Municipal , Shandong Province. By the year of 1995 , the irrigation area under pipe conveyancesystem usign this type of pipe has reached 74000 hectares. By calculation, about 27.7million ㎥ water, 2.88 million kWh power , 0.167 million man power and 1528 hectares cu tivated land will be saved one year, adding value of agriculture output increased by 10 million kg. The total economic benefits amount to 0.92 million US$ a year. The paper presents the pipe making course and its application on a large scale area.

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영산강 하류권역 하상퇴적물의 지화학적 특성과 오염평가 (Geochemical Characteristics and Contamination Assessment of Surface Sediments in Lower Yeongsan River System)

  • 윤석태;고영구;오강호;문병찬;김해경
    • 환경영향평가
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    • 제13권5호
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    • pp.251-262
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    • 2004
  • In order to investigate the geochemical characteristics of surface sediments in lower Yeongsan river system, sediment samples from the main stream of Yeongsan river, Gomakwon and Hampyeong streams were collected and analyzed for grain size and metal and organic carbon contents. The sediment types of the streams widely vary from pebble to mud. The metal contents in the sediments are mainly dependent on grain size of the sediments, geology around the streams and organic matter contents from the domestic sewage. Enrichment factor (EF) representing the degree of metal contamination in the sediments are relatively low in the study area. But, high Zn and Pb values seem to be from the study area, partly.