• Title/Summary/Keyword: 강도래

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Observation of the Adults and Eggs of Two Species of the Family Perlidae(Plecoptera) to Korea (강도래과(강도래목) 2 종에 대한 성충 및 란의 외부형태 관찰)

  • 나철호;백순기;조영관
    • Animal Systematics, Evolution and Diversity
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    • v.7 no.1
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    • pp.101-110
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    • 1991

  • Two species of Perlidae, Oyamia coreana and Kiotina decorata which were collected in mountain valley of the Chonnam, Chonguk and Kyongnam provinces, south Korea are reported for the first time from Korea, with description of the external morphology of their eggs by SEM.

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Fundamental Characteristics of Concrete for Nuclear Power Plant Using Crushed Sand (부순모래 사용에 따른 원전 구조물용 콘크리트의 기초적 특성)

  • Park, Sung-Hak;Kim, Kyung-Hwan;Choi, Byung-Keol;Choi, Yun-Wang
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.5 no.2
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    • pp.168-176
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    • 2017

  • This study, as a research for using crushed sand as a fine aggregate of concrete for nuclear structures, we improved the performance of impact crusher in the existing crushed sand production process and adjusted grain size to conform to ASTM C 33 The shape and grain size characteristics of a crushed sand were examined and concrete was prepared according to the substitution ratio of the sand to investigate the properties of fresh concrete and hardened concrete. The experimental results show that most of the concrete characteristics are equivalent to those of concrete using only heavy sand. However, when the substitution rate of steel sand exceeds 50%, the amount of air, compressive strength and tensile strength are somewhat reduced.

  • https://doi.org/10.14190/JRCR.2017.5.2.168 인용 PDF KSCI