• Title/Summary/Keyword: 편수

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Flow Characteristics of Curved Channel According to Influx form in Experimental Model (실험수로에서 유입부 형상에 따른 만곡하도의 흐름특성)

  • Ahn, Seung Seop;Lee, Sang Il;Park, Dong Il;Kim, Jung Ki
    • 한국방재학회:학술대회논문집
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    • 2011.02a
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    • pp.204-204
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    • 2011
  • 자연하천의 만곡부에서는 원심력에 의하여 수위상승 이나 침식 등으로 제방이 파괴되고 월류되어 홍수피해가 빈번하게 발생된다. 그러므로 자연하천의 만곡부는 하천정비 및 안정하도의 유지관리를 위해 매우 중요한 하도구간중의 하나이다. 본 연구에서는 하도 만곡부의 흐름특성 연구를 위하여 만곡 유입부 형상에 따라 $90^{\circ}$만곡부의 실험수로에 대한 유속, 편수위 및 편경사의 변화특성을 검토하였다. 분석결과 먼저, 만곡정도에 관계없이 유량이 증가할수록 만곡부의 최대 최소 유속차 또한 증가하는 것으로 검토되었다. 다음으로 유입부 형상이 $90^{\circ}$인 지점에서 최대 횡방향 수면경사가 발생하였으며 직선하도에 비하여 최대 8% 정도 기울어진 것으로 검토되었다. 본 연구의 결과에서 검토된 만곡 하천의 수리특성과 편경사의 경향 등을 하천정비 또는 실시계획수립에 반영한다면 치수적으로 안전하고 보다 친환경적인 하천계획이 가능할 것으로 판단된다.

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On the Mathematical Terminology before the First Editing Material (편수 자료 이전의 수학 용어에 대해)

  • Her, Min
    • Journal for History of Mathematics
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    • v.31 no.3
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    • pp.111-126
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    • 2018
  • At present, most of school mathematical terms in elementary and secondary curriculums of Korea are Sino-Korean words. 1964 Mathematical Editing Material, which aimed to unify mathematical terms into mainly Sino-Korean words, was considered a key factor for this situation. 1964 Editing Material depended heavily on 1956 Mathematical Terminology, which contains a lot of Korean native words and displays the school mathematical terms after 1945. There are many Korean native words in the Second Mathematical Curriculum. This shows that Korean native words of mathematics had been consolidated to some extent at that time. In North Korea, a lot of Korean native words are still used in mathematics. Some Sino-Korean words were recently changed to Korean native words in South Korea. 1956 Mathematical Terminology tells the method to make Korean native words of mathematics and will be an excellent guide for making Korean native words.

Relation between KARP Membership and Articles Published in KARP Journal on the Yearly Basis (대한방사선방어학회 회원수와 방어학회지에 게재된 년간 발표 논문 편수와의 관계 고찰)

  • Ro, Seung-Gy;Lee, Jai-Ki
    • Journal of Radiation Protection and Research
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    • v.14 no.1
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    • pp.71-74
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    • 1989
  • A statistical model for the relation between KARP membership and articles published in the KARP Journal on the yearly basis was obtained by using the least-squares method. From this, KARP membership potent to publish the KARP Journal up to 4 numbers a year were projected. It is revealed that at least 650 KARP members are needed.

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반세기를 거치며 쏟아 낸 시작 열정-"성탄제"에서 "달맞이 꽃"까지

  • Kim, Jong-Gil
    • The Korean Publising Journal, Monthly
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    • s.234
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    • pp.22-23
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    • 1998
  • 등단 50주년을 맞고서도 시집으로 묶은 총편수가 150편밖에 되지 않으니 무던히도 과작이었던 셈이다. 생전에 300편은 쓰고 싶은데 그 목표를 달성할 수 있을는지. 노욕은 금물이니 한 편 한 편 정성을 다하는 자세를 견지하련다.

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Studies on Differentiation of a Paddy Weed, Bur Beggarticks(Bidens tripartita L.) (논 잡초(雜草) 가막사리(Bidens tripartita L.) 생태종(生態種)의 분화(分化)에 관(關)한 연구(硏究))

  • Kim, Myung-Hyun;Rho, Yeong-Deok
    • Korean Journal of Weed Science
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    • v.17 no.3
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    • pp.303-309
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    • 1997
  • Variation of morphological and physiological traits of 50 Bidens tripartita accessions were studied and the accessions were grouped through cluster analysis based on four major characters; plant type, leaf partition, achene length, days to flowering. Bidens tripartite accessions have shown significant variations in plant type, stem length, days to flowering, leaf shape, leaf partition, chlorophyll content, leaf color, stem color, achene color, achene length and achene shape. Most of Bidens tripartite accessions appeared to have strong dormancy and also photodormancy with some exceptions. Plants could be classified into 5 types from straight(I) to triangle(V), and intermediate diamond type(III) was prevalent. The plant type score has negative correlation with the stem length. None, three, and five part leaved plants were observed and most of them were three or five parted. Leaf partition had negative correlation with achene length and chlorophyll content. Average days to flowering was 108 days in the range of 94~141 days. It had positive correlation with achene length and leaf shape and negative correlation with achene color. Average achene length was 10.0mm and it had positive correlation with achene shape, stem length, days to flowering and leaf shape. It also had negative correlation with leaf color, stem color, achene color, leaf partition. Bidens tripartite accessions could be divided into identifiable six groups from the cluster analysis at the distance 0.06 using Ward's minimum-variance method.

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Unsteady RANS computations of turbulent flow in a high-amplitude meandering channel (고진폭 만곡수로에서 난류흐름의 비정상 RANS 수치모의)

  • Lee, Seungkyu;Paik, Joongcheol
    • Journal of Korea Water Resources Association
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    • v.50 no.2
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    • pp.89-97
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    • 2017
  • Turbulent flow structure in the high amplitude meandering channel is complex due to secondary recirculation with helicoidal motions and shear layers formed by flow separation from the curved sidewall. In this work, the secondary flow and the superelevation of the water surface produced in the high-amplitude Kinoshita channel are reproduced by the unsteady Reynolds-averaged Navier-Stokes (RANS) computations using the VOF technique for resolving the variation of water surface elevation and three statistical turbulence models ($k-{\varepsilon}$, RNG $k-{\varepsilon}$, $k-{\omega}$ SST). The numerical results computed by a second-order accurate finite volume method are compared with an existing experimental measurement. Among applied turbulence models, $k-{\omega}$ SST model relatively well predicts overall distribution of the secondary recirculation in the Kinoshita channel, while all three models yield similar prediction of water superelevation transverse slope. The secondary recirculation driven by the radial acceleration in the upstream bend affects the flow structure in the downstream bend, which yields a pair of counter-rotating vortices at the bend apex. This complex flow pattern is reasonably well reproduced by the $k-{\omega}$ SST model. Both $k-{\varepsilon}$ based models fail to predict the clockwise-rotating vortex between a pair of counter-rotating vortices which was observed in the experiment. Regardless of applied turbulence models, the present computations using the VOF method appear to well reproduce the superelevation of water surface through the meandering channel.