• Title/Summary/Keyword: burying depth

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Model Test of Stabilizing Measures for Ground Failure Due to Soft Ground Excavation (연약지반 굴착에 따른 지반파괴 억지대책 실내모형 실험)

  • Kim, Jae-Hong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.34 no.3
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    • pp.907-917
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    • 2014
  • When conducting excavations after burying the soft ground, even if the retaining walls are installed, failure often occurs within backfill. In order to minimize the occurrences of failures, model test was performed after the installation of stabilizing piles to investigate the stabilizing effects. The model chamber is set up with clay foundation reinforced with and without stabilizing piles. During the excavation of clay foundation, the subsidence, pore water pressure, and soil pressure along the excavation were measured. As a result of the model test, the increase of excavation levels and the reduction of subsidence of back ground were observed with the stabilizing piles, compared to those without the stabilizing piles. The installation of stabilizing piles does not influence the pore water pressure change, but induces less subsidence rate. In addition, the depth of excavation has a significant effect on the back ground and it was evaluated that the maximum subsidence occurs as it is closer to the excavation point.

Study on Prevention of Foreign Material Formation in Sclerotium of Poria cocos. (복령 균핵내 이물질 생성 방지 연구)

  • 장현유
    • Korean Journal of Plant Resources
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    • v.13 no.2
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    • pp.147-153
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    • 2000
  • Experiments were carried out to determine the effects of culturing conditions DCI(Day required for Colonization after Inoculation), CR(Contamination Rate), MD(Mycelial Density), DPI(Day required for Primordial sclerotia formation after Inoculation), yields, and degree of the foreign materials formations in Poria cocos sclerotia. The upper and bottom side of wood logs were covered with gauze, rice hull and floating leaves, vinyl, or covering cloth in order to prevent foreign material formations in p. cocos. The major results were positive in the order of rice hull, floating leaf, vinyl, gauze, and covering cloth covered and dwindled. In case of the upper and bottom sides of the wood logs covered with rice hull, DCI required 50 days more when compared with the control group(45 days) and CR was 0%, while the control group showed 2% CR. MD was excellent in case of conventional methods as against control's. DPI required 17~20 days less when compared with the control group(82 days). Yields of p. cocos in case of the upper and bottom side of wood logs covered with rice hull were 5.87kg, which is 35.7% higher than that of the control group(4.33kg), and 5.62kg in the case of upper sides cover only(increased by 29.8% compared with control), and 5.59kg in the case of bottom side cover only(increased by 29.1% compared with control), and foreign materials were none. In a separate experiment, where the upper and bottom sides of wood logs were covered with rice hull to prevent the foreign material formation, the results were as follows : Sclerotia formation status and quality of P. cocos were effective in the order of 20cm, 40cm, and 60cm of buring depth and dwindled. In 20cm of burying depth, DCI was shortened by 5 days and CR was none, while the control group showed 2% CR. MD was remarkably fine at the mulched conditions. DPI was shortened by 20 days when compared with the control(62 days).

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Bionomics and a Lana Sampling Method of Coppery Wireworm, Selatosomus puncticollis (Motschulsky), (Coleoptera: Elateridae) in Potato Field (청동방아벌레(Selatosomus puncticollis Motschulsky)의 생태적 특성 및 감자포장내 유충밀도 조사법)

  • Kwon, Min;Park, Cheon-Soo;Lee, Seung-Hwan
    • Korean journal of applied entomology
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    • v.43 no.3 s.136
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    • pp.195-200
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    • 2004
  • The occurrence pattern and bionomics of Selatosomus puncticollis (Motschulsky) were surveyed in three net house (6$\times$70m) in the field and in a laboratory ($20^{\circ}C$, RH$75\%$, L16/DB). Emergence of hibernated adults of S. puncricollis started from early May, reached peak at early June and diminished in late June. Occurrence rate to total number was $42.1\%$ in early June and $31.7\%$ in late May, when most of hibernated adults emerged at these periods. Adults started to oviposit from mid June, and eggs hatched from early July Larvae turned into pupae from mid July and emerged to adults from mid August. Egg-period was 23 days and pupal period was 21 days. It is estimated that preovipositional period and larval period were approximately 10 months and 30 months, respectively. Wireworms were distributed at the soil depth of 10-5 cm, $56.8\%$ in 1997 and $45.8\%$ in 1998. To establish bait techniques to attract wireworms in the soil, six baits: pieces of potato, carrot, and sweet potato, wheat grains, corns, and flour dough wrapped with gauze, were buried at 15 cm of soil depth, and collected after 5 and 10 days. The numbers of wireworms attracted by potato pieces, wheat grains and sweet potato pieces after 10 days were 1.8, 1.6, and 1.4/bait, respectively. Therefore, burying potato pieces at 15 cm of soil depth and collected after 10 days could be recommended as a wireworm baiting technique.