• Title/Summary/Keyword: 직선 강상자

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A Study on the Distortional Analysis of Curved Steel Box Girders and Determination of Diaphragm Spacing (곡선 강상자형 거더의 뒤틀림 해석 및 격벽간격산정)

  • Koo, Min Se;Yoon, Wo Hyun;Lee, Ho Kyoung;Kim, Dae Hong
    • Journal of Korean Society of Steel Construction
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    • v.15 no.2
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    • pp.125-135
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    • 2003
  • A 3-dimensional model of curved steel box girder bridges without diaphragm was presented. This model yielded results that were consistent with those of the parameter analysis using the BEF and Ritz methods. Se veralmodels with diaphragms were analyzed to estimate the appropriate diaphragm spacing. In case of 50m span, models A-10, A-20, A-30, B-10, B-20, and B-30 were found to have 5(8.3m), 7(6.25m), 8(5.5m), 4(10m), 6(7.1m), and 7(6.25m) diaphragms, respectively. In addition, a formula that presents the ratio of distortional stress to bending stresswas created from the results of the 3-dimensional FEM model analysis.

Characterization of Fusarium solani Causing Fusarium Root Rot of Lisianthus in Korea (꽃도라지 뿌리썩음병을 일으키는 Fusarium solani 의 특성)

  • Choi, Hyo-Won;Hong, Sung Kee;Lee, Young Kee;Kim, Jeomsoon;Lee, Jae Guem;Kim, Hyo Won;Kang, Eun Hye;Lee, Eun Hyeong
    • The Korean Journal of Mycology
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    • v.45 no.1
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    • pp.74-82
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    • 2017
  • Lisianthus (Eustoma grandiflorum) is a flowering ornamental plant used widely in Korea. In 2015, wilting, damping-off, stunting, and root rot symptoms were observed in lisianthus plants of Yeoju and Gimhae, Korea. Affected seedlings appeared yellow and showed poor development of root systems in the field and in nursery boxes. Furthermore, affected plants were yellow, stunted, and died at approximately 2-3 months after transplanting. Fusarium species were consistently isolated from the basal stems of diseased plants. Nine isolates were identified as Fusarium solani based on morphological characteristics. Macroconidia of isolates were relatively wide, straight-to-slightly curved, and microconidia formed in false heads on long monophialides. Abundant chlamydospores were produced at the middle or tips of hyphae. To confirm this identification, a molecular analysis of the translation elongation factor 1 alpha (TEF) and RNA polymerase II subunit (RPB2) genes was conducted. The sequences of TEF and RPB2 showed 99.2-99.9% and 98.0-98.1% similarity, respectively, to those of reference F. solani strains in NCBI GenBank. Pathogenicity was tested using root dipping inoculation of healthy lisianthus seedlings. Symptoms were observed within 7 days of inoculation only in inoculated plants. This is the first report of F. solani causing Fusarium root rot on lisianthus in Korea.