• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.462-466
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• 2006

Close-to-nature stream evaluation is one of the processing to make the streams over in order to keep them natural. It is integral to evaluate and make an accurate analysis of them on the purpose of maintaining streams healthy. For many instances, there are, stream organization evaluation for restoration by German government, evaluation for ecosystem protection in natural preserves by New Zealand government, and stream-view evaluation for restoration by Britain government so on. In case of the country there are analysis and evaluation of stream physical organization by Cho, Yong-hyun, Close-to-nature stream evaluation for restoration by Kim, Dong-chan, evaluation of stream properties in korea by Park, Bong-jin. Close-to-nature evaluation by Lim, Chan-uk, that is advanced version of Park, Bong-jin's, shows form of stream including waterway curve, sand bar, diversity of flow, river bed material, diversity of minor bed, minor bed bank protection works, bank protection material. It also does environment of stream including side of minor bed vegetation, width of surface of the water/width of the river etc.. By the way, this evaluation does not have free access to apply those details above in the field, it often happens that you get various outcome from the one spot. so you must need more realistic testing method to obtain more accurate data. Remote sensing method is highly recommended because this is very useful for collecting realistic data of vegetation index. what is more, it can not only scan even the minimum area within its resolving power but also do obtain data anytime. Vegetation index indicates Ratio vegetation index, Normalized difference vegetation index, Soil adjusted vegetation index, Atmospherically resistant vegetation index etc.. The research is focusing on Cheokgwa stream which is the branch of Taehwa river and shows 19 sectioned Close-to-nature stream performed according to the method by Lim, chan-uk. Besides let you know vegetation index came from image data of satellite landsat 7 with the variation of buffering area, of the day 9. may. 2003. Of all, the outcome 0.758 at 200m buffer-zone of NDVI was the best we have got so far.

• Korean journal of food and cookery science
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• v.21 no.1 s.85
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• pp.53-63
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• 2005

This study was carried out to determine the inhibitory effect of methanol extract from kimchi ingredients against Salmonella typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Esherichia coli which are pathogenic microorganisms and Aspergillus sp. Penicillium sp. Antimicrobial activity of methanol extracts was tested against bacteria by paper disc method. Antifungal activity of methanol extracts was shown by hyphal growth inhibition ratio. The methanol extracts from all materials were effective against E. coli among them. And the antimicrobial activity of the methanol extracts from ginger and onion were lower than the others. The antifungal activity of the methanol extracts from radish, ginger, and garlic were effective against Aspergillus sp. and Penicillium sp. In the result of identifying antimicrobial effect rate, the methanol extracts from red pepper and radish had more than $40\%$ against S. typhimurium and more than $30\%$ against E. coli. Also the methanol extracts from onion had an high inhibitory effect rate of more than $50\%$ against S. typhimurium and that from garlic had more than $60\%$ against S. aureus. The minimum inhibitory concentration(MIC) of red pepper was examined 500 $\mu$g/mL against L. monocytogenes. This value was the lowest among the others.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.727-743
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• 1996

To know the floristic composition, vortical distribution and community structure of marine benthic algae inhabiting in the intertidal and subtidal zones of Yongil Bay, east coast of Korea, the study has performed using the quadrat method along a transect line from July, 1995 to June, 1996. In this area, a total of 144 species including 2 new red algae to Korea was found: 5 blue-green, 18 green, 20 brown and 101 red algae. The representative species throughout the year were Ulva pertusa, Gelidium amansii and Symphyocladia latiuscula. Dominant species were Sargassum thunbergii in spring, U. pertusa in summer and autumn. In winter, Chondrus ocellatus and Monostroma grevillei occurred dominantly. The standing crop exhibited mean value as $185.8g/m^2$ dry weight. Maximum value was recorded in spring $(267.3g/m^2)$ and minimum was observed in winter $(93.7g/m^2)$. Shannon's species diversity (H') and evenness (J') as maximum value were recorded in spring, whereas minimum values were shown in winter. Vertical distribution, rerognized by cluster analysis based on relative coverage of the species, could be divided into two or three algal groups except spring. In general, green algae (M. grevillei, Capsosiphon fulvescens, U. pefusa, Enteromorpha compressa) and brown algae (Sargassum fulvellum, S. thunbergii) were represented in the upper and middle zone and red algae (G. amansii, C. ocellatus, S. latiuscula, Crateloupia okamurae, Pachymeniopsis eilliptica) in the lower zone. The algal community varied according to season and environmental conditions. Particularly, seasonal variation of vortical distribution seemed to be affected primarily by water temperature. Also seasonal tidal level and tolerance of algal species to desiccation appeared to be associated with it in this area.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.1153-1156
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• 2012

Daegwallyeong area to be formed along the mountainous terrain more above 800 m of sea level is known as the cold zone to occur frequently wind, rain and fog. This study to evaluate the stability of crop production and agricultural production potential in the Daegwallyeong was calculated for the low temperature frequency of occurrence and potential evapotranspiration changes with announce the release of Korea Meteorological Administration (KMA) from 1972 to 2009 up to 38 years. Evapotranspiration calculated FAO and other international standard method authorized under the PENMAN-MONTEITH Method was used, and the low temperature onset and frequency of the Gumbel probability density function was used. As a result, the variation of day evaporation for 38 years were showed to respectively width of variation from maximum $9mm\;day^{-1}$ to minimum $0.5mm\;day^{-1}$. The frequency of reappearance to first emergence day that lasts more than 5 days with temperature $5^{\circ}C$ over is 3 April a 50-year frequency, 10 April a 25-year frequency, 20 April a 10-year frequency, 28 April a 5-year frequency, 8 May a 2-year frequency. Psychrotrophic crop to growth temperature more than $5^{\circ}C$ can be secured to stable production with planting after May 8, prior to planting for normal growth can be seen that the risk of growth.

• Tunnel and Underground Space
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• v.11 no.2
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• pp.109-119
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• 2001

Up to now single large cavern was excavated for each undergroud hydraulic powerhouse in Korea. But the Yangyang underground hydraulic powerhouse consists of two large caverns; a powerhouse cavern and main transformer cavern. In this carte, the structural stability of the caverns, especially the rock pillar formed between two large caverns, should be guaranteed to be sound to make the caverns permanently sustainable. In this research, the Distinct Element Method(DEM) was used to analyze the structural stability of two caverns and the rock pillar. The Barton-Bandis joint model was used as a constitutive model. The moot significant parameters such as in-site stress, JRC of in-situ natural joints, and spatial distribution characteristics of discontinuities were acquired through field investigation. In addition, two different cases; 1) with no support system and 2) with a support system, were analysed to optimize a support system and to investigate reinforcing effects of a support system. The results of analysis horizontal displacement and joint shear displacement proved to be reduced with the support system. The relaxed zone in the rock pilar also proved to be reduced in conjunction with the support system. Having a support system in place provided the fact that the non zero minimum principal stresses were still acting in the rock pillar so that the pillar was not under uniaxial compressive condition but under triaxial compressive condition. The structural stability f an approximately 36 m wide rock pillar between two large caverns was assured with the appropriate support system.

• The Korea Journal of Herbology
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• v.30 no.6
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• pp.55-61
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• 2015

Objectives : Yongdamgosam-hwan(YGH) has been used as a traditional medicine from old times for antiinflammatory effects. Streptococcus mutans(S. mutans) is known as a prime bacteria responsible for causing caries by forming a biofilm referred to as dental plaque on the tooth surface. But antimicrobial activity of YGH with dental disease is not sufficiently understood. This study was designed to investigate the effects of YGH ethanol extract on antimicrobial effect against Streptococcus mutans.Methods : The antimicrobial effect of YGH ethanol extract was assessed by the paper disk diffusion method and optical density method to determine minimum inhibition concentration(MIC), also observed by fractional inhibitory concentration index(FICI) and time-kill assay to figure out the synergic effect on the combination of YGH ethanol extract with antibiotics.Results : The YGH ethanol extract 500 μg was 7.5-8.5 mm diameter of clear zone of inhibition against Streptococcus mutans in a concentration-dependent manner and MIC was 250 μg/mL. The administration of the ethanol extract in combination with gentamicin and streptomycin induced a reduction of ≥4-8-fold in all tested bacteria. Furthermore, time-kill study was found that a combination of YGH ethanol extract with oxacillin and streptomycin produced a more rapid decrease in the concentration of bacteria CFU/mL than the YGH ethanol extract or antibiotics alone.Conclusions : As a result, the YGH ethanol extract has good antimicrobial effects. And the results suggest that YGH could be employed as a natural antibacterial agent in dental care products.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.187-194
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• 2010

As the design of the pillar width (PW) of the parallel tunnels in downtown area, in which are located in plains zone with deep alluvium compared with mountain tunnels, is directly related with pre-compensation payment and costs of the underground area, it has to be planned as to keep minimum distance while securing the stability of the parallel tunnels. Although PW of downtown road tunnel in Korea is standardized as 1.5D(D: diameter of the tunnels), PW sometimes has to be reduced within 1.5D to adjust the tunnel lines to the city plan in the cases of the inlet and outlet of the tunnels. In this paper, the design and the analyses of optimum PW of the NATM type road tunnel in the downtown area are introduced. The relationship among the tunnel line planning and underground compensation fee, and ground characteristics are evaluated. In the determination of PW distance, the numerical analyses of underground road tunnels were performed, including the use of the strength decrease method and strength/stress ratio method. In the cases of inlet and outlet part of the tunnels where the stability of the pillars is poor due to contiguous construction of the parallel tunnels, the reinforcement methods are recommended for securing the stability. Numerical verification was performed for the reinforcement proposed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.699-714
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• 2022

The objective of this study is to suggest a safe and economical pillar reinforcement method when very near-twin tunnels with a minimum interval of 1 m passes through a soft zone such as weathered soil or weathered rock. A standard cross-sectional view of a two-lane road tunnel was applied to suggest a pillar reinforcement method for the very near-twin tunnels. The thickness of the pillar was 1 m. The ground condition around the tunnel was weathered soil or weathered rock. There were four reinforcement methods for pillar stability evaluation. These were rock bolt reinforcement, pre-stressed steel strand reinforcement, horizontal steel pipe grouting reinforcement, horizontal steel pipe grouting + prestressed steel strand reinforcement. When the ground condition was weathered soil, only the pillar reinforced the horizontal steel pipe grouting + prestressed steel strand did not failed. When the ground condition was weathered rock, there were no failure of the pillar reinforced the horizontal steel pipe grouting or the horizontal steel pipe grouting + prestressed steel strand. It is considered that the horizontal steel pipe grouting reinforcement played a role in increasing the stability of the upper part of the pillar by supporting the upper load applied to the upper part of the pillar.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.374-384
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• 1999

Benthic marine algal flora and community structure of Yongho-dong area in Pusan, Korea were investigated seasonally in intertidal and subtidal zones by a quadrat method along 5 transect lines from July 1996 to April 1997. In this area, a total of 99 species including 3 blue-green, 13 green, 26 brown and 57 red algae was found. Among them, 33 taxa, together with dominant Ulva pertusa and Corallina pilulifera, occurred throughout the year. Enteromorpha spp. and Ulva spp. vertically distributed in upper and middle zone, while Simphyocladia latiuscula, Chondria crassicaulis, Corallina pilulifera and Sargassum sup. in lower zones. Biomass per unit area exhibited a wide range of variation, from 1,241 g/$m^2$(spring) to 1,648 g/$m^2$(summer) in fresh weight. Maximum and minimum species diversity were recorded in spring and autumn, respectively. Results of the UPGAM cluster analysis suggest that the examined 5 sites can be divided into two groups, sites exposed to open sea (transects 1, 2, 3) and comparatively sheltered sites (transects 4, 5) faced with the Pusan Harbor. The former group is represented by large brown algae, Sargassum and Hizikia, while Ulva pertusa and Lomentaria species are mainly found in the latter group. A calcareous alga, Corallina pilulifera occurred dominantly in both groups throughout the year. In conclusion, number of species in this area was remarkably reduced as compared to the previous data. This result may suggest probably more change of algal vegetation in future, considering the physical and chemical pollutions loaded in the coastal marine environment of this area.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.667-673
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• 2017

This study was carried out to verify the antimicrobial effect of Graviola leaves against pathogenic bacteria for the purpose of developing an antibacterial material. The extraction conditions of graviola leaves were $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, and graviloa leaves werewater extracted at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$.The extraction yields and extraction conditions were determined. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was evaluated by agar diffusion method. The extraction yields were 3.02%, 14.73% and 20.76% at $60^{\circ}C$, $80^{\circ}C$ and $98^{\circ}C$, respectively. The antimicrobial activity against S. epidermidis, S. aureus and E. coli TOP10 was found in S. epidermidis.In the samples extracted at $98^{\circ}C$, a clear zone of 13 mm was observed at 200 mg/mL and of 20 mm at 500 mg/mL. The MIC was 100 mg/mL. The higher the extraction temperature and concentration, the better was the growth inhibition effect. As a result, the natural antimicrobial activity contained in natural materials can solve the problem of resistance to antibiotics. It is considered that antimicrobial activity against S. epidermidis in skin is highly applicable to basic cosmetics and cosmetic materials.