• Title/Summary/Keyword: sill

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Damage Contribution Rate Analysis by Accidental Tunnel Explosion at a Multi-layered Room and Pillar Mine (우발적 갱도폭발에 따른 다층 주방식 채광광산 구조요인별 피해 기여도 분석)

  • Ko, Young-Hun;Yang, Hyung-Sik;Kim, Seung-Jun
    • Explosives and Blasting
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    • v.35 no.3
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    • pp.1-8
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    • 2017
  • In this paper, parametric studies are conducted to evaluate the contribute effect of multi layered room and pillar mine structures by underground accidental explosions. Influence of PPV(Peak Particle Velocity) obtained from large explosion at a multi layered room and pillar mine was numerically simulated by using AUTODYN. Parameters for contribution rate Analysis was analyzed by the robust design method. Orthogonal array is $L_9(3^4)$, which was adopted in this study, the parameters were pillar height, pillar width, mine span and sill pillar of 3 levels. Results of analysis showed that bottom mine of vertical direction from explosion point are most affected by pillar height, followed by sill pillar thickness, mine span and pillar width. Parameters affecting adjacent mine of horizontal direction from explosion are in the order of pillar width, mine span, pillar height and sill pillar thickness.

Inhibitory Effects of Ethanol Extracts from Pine Buds (Pinus densiflora) on Angiotensin Converting Enzyme, Xanthine Oxidase and Nitric Oxide Synthesis (소나무 새순 에탄올 추출물의 angiotensin converting enzyme, xanthine oxidase 및 nitrix oxide synthase 활성)

  • Cho, Eun-Kyung;Song, Hyo-Ju;Cho, Hea-Eun;Kim, Mi-Hyang;Choi, In-Soon;Choi, Young-Ju
    • Journal of Life Science
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    • v.19 no.11
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    • pp.1629-1636
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    • 2009
  • Pine trees (Pinus densiflora Sieb. et Zacc.) have been used as a traditional health-promoting medicinal food in Korea. This research was performed to determine the antioxidative and antibacterial activities, tyrosinase, nitric oxide synthesis, angiotensin converting enzyme (ACE), and xanthine oxidase inhibition effects of the pine bud ethanol extract (PBE). Antioxidative activities of PBE were measured by using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) free radical scavenging activity and superoxide dismutase-like activity (SODA). DPPH radical scavenging and SOD-like activities of PBE were remarkably increased in a dose-dependent manner, and were about 88.9% and 47.9% at 1 mg/ml and 10 mg/ml, respectively. The xanthine oxidase and angiotensin converting enzyme activities were inhibited about 71.9% and 60.8% at 1 mg/ml and $100{\mu}g/ml$ of PBE, respectively. The tyrosinase inhibitory activities of PBE were slightly increased in a dose-dependent manner. The PBE showed strong antimicrobial activities on Escherichia coli (E. coli) and Vibrio paraheamolyticus. Stimulation of the macrophages RAW264.7 cells with lipopolysaccharide (LPS) resulted in increased production of nitric oxide (NO) in the medium. However, NO synthesis was reduced up to 54% by addition of PBE at $200{\mu}g/ml$. These results revealed that pine buds have a strong antioxidative and anti-inflammatory activity, and exhibit angiotensin converting enzyme and xanthine oxidase inhibitory activities. This suggests that pine buds have the greatest property as a source for natural health products.

ALPINE KARST IN EASTCENTRAL KOREA

  • Oh, Jongwoo
    • Journal of the speleological society of Korea
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    • v.41 no.1
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    • pp.16-26
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    • 1994
  • Karst in Korean peninsula is not widely known. Since karst studies had been initiated a few hundred years ago based on the historic records “Dong Guck Ye Jee Seoung Lam” and “Sae Jong Sill Rok Gee Ri Jee” (1993, Oh), modern caverns during the 60s have inactively started to search on the karst phenomena to the eastern mountaineious areas.(omitted)

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