• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.5
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• pp.109-116
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• 2010

Infiltration and the rising level of groundwater caused by rainfall are a major cause of the landslide and sliding. In order to secure the safety factor of slope, the slope stabilization and reinforcement works are used to enhance consistency. Nailing, Slope Drainage method and the surface vegetation measures can be simultaneously applied in the Mass Nail method, which is also environmental friendly reinforcement method. To demonstrate the reinforcement effect of a strengthened slope by Mass Nail, the changes in water contents by rainfall were considered while performing Scale Model Test. As a result, safety factor of reinforced slope was about 1.4~2.3 times increased on the unstrength slope. In the case of increasing water content 10% to 22%, The maximum stress was reduced to 12%~24% at the average rate of 18% on the unstrength slope and the reinforced slope by the Mass Nail Method was reduced to 4%~23% at the average rate of 14%.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.243-244
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• 2009

진공 chamber 내부 plasma를 외부에서 view port를 통한 확인 및 촬영보다 효율을 높이기 위하여 chamber 내부에 무선 camera (IVC : internal vacuum camera)를 삽입하여 더 세밀하게 plasma를 촬영하였고 view port로 확인이 불가능한 부분을 촬영 및 녹화하였다. 외부 view port로 확인할 수 없는 원거리 플라즈마 소스 (remote plasma source, RPS)와 in-line type의 chamber에서 동적 (dynamic) 증착이 이루어지는 substrate에 camera를 부착하여 이동 중 target 위쪽에 방전된 plasma, ICP (inductively coupled plasma) antenna를 진공 중 chamber 내부에서 촬영 및 녹화하였다.

• Journal of the Korean Wood Science and Technology
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• v.36 no.1
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• pp.79-87
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• 2008

Many researchers have studied on rooftop greening that can be installed in abandoned spaces on a building roof. The most important issue in rooftop greening is the soil weight problem. The light greening materials are needed to solve this problem. Therefore, many alternative materials against the soil were investigated for rooftop greening. In this study, the waste wood chips and the waste paper slurry were evaluated as the lightweight vegetation foundation for rooftop greening. It also has a meaning for recycling of waste materials. The mixture ratio of waste wood chips to waste paper slurry for the board (the foundation of greening) was 60 to 40. The wet strength resin and the sizing agent were additionally added with different amount. After the forming of the board, physical and chemical properties were tested with the variation of wet strength resin and sizing agent. As the result of the test, the board with 15% of wet strength resin in the wet condition showed the highest strength. Futhermore, the moisture evaporation loss from the board surface with sizing agent was much lower than that from the board without sizing agent. Therefore, it was clear that the sizing agent was effective for water retention. The change of thickness in the wet condition was less than 1 mm, and it showed that the board is the predominant material on the dimensional stability. The average pH value of the board was ranged from 7.6 to 8.25.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.295-303
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• 2019

This study investigated the effects of various cultivation pots on Betula platyphylla var. japonica seedlings in order to select suitable pots for the production of healthy seedlings for the ecological revegetation. We used six types of the pots natural pot, natural pot with inside 5 mm width root turning bump, natural pot with inside 10 mm width root turning bump, negative-phototropism pot, negative-phototropism pot with inside 5 mm width root turning bump, and negative-phototropism pot with inside 10 mm width root turning bump. As greenhouse cultivation provided a high level of control of irrigation and temperature, the seedlings did not show any significant differences in plant height, number of branches, and diameter at root collar, but showed a significant difference in root growth among the different types of pots. The root growth was best in the negative-phototropism pot. In the negative-phototropism, the roots grew in a vertical shape, while they grew abnormally in a spiral shape in the natural pots. In outdoor cultivation, the growth of seedlings showed significant differences according to container types. The seedlings grown in specially manufactured negative-phototropism pots were most excellent in all of the height, number of branches, diameter at root collar and root growth. As for the seedlings grown in the negative-phototropism pots, their roots grew vertically and thus their rooting was well established after they were transplanted outdoor. A size of less than 5 mm ridge installed in the negative-phototropism was found to be appropriate for the seedling growth. These results showed that the negative-phototropism pot would be best suitable for the growth of Betula platyphylla var. japonica seedlings and for the production of seedling for ecological revegetation.

• Journal of the Korean Geotechnical Society
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• v.21 no.5
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• pp.93-101
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• 2005

The formation of slopes is unavoidable under the special circumstance of Korea where $7%$ of the whole area are composed of mountains and civil engineering projects such as road and site developments are increasing with industrial development and horizontal expansions of urban area. Stability of slopes is one of quite important issues under special meteorological characteristics that over two-thirds of annual average rainfall is concentrated in summer season and the localized torrential downpour is getting more frequent recently. As a result of these circumstances, partial slope failures by debris flow of the high water content soils occur frequently in cut soil slopes. In this case of debris flow slope failure, slope declination method is selected fur the stable recovery because it is impossible to recover entirely by existing recovery methods. Seeding or special grass planting methods are followed separately without exception. The method by which entire recover with bigger stability ratio would be possible and grass planting work would be done simultaneously is developed. For debris flow failure slopes, this study secured the safety of slopes by preventing the inflow of rainwater and scour using geosynthetics-reinforced embankment, and created nature-friendly slopes by planting trees on the slopes.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.304-313
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• 2019

Biopolymer based on microbial β-glucan and xanthan gum is effective for vegetation and has a function of enhancing soil strength, which can be used as soil reinforcement and stabilization materials in river embankment. The purpose of this study is to verify the vegetation effect of the surface of levee by biopolymer with seed spraying method. Mixed soils with biopolymer were used to cover the surface of embankments. The strength is higher in biopolymer-treated soil and xanthan gum based biopolymer has advantage for quality control in field scale. In addition, the vegetation of F. arundinacea and L. perenne showed various reactions with types of biopolymers. Biopolymer has a positive effect on the vegetation of them. In contrast, root growth tended to decrease in biopolymer-treated soils. The results indicate that root growth is slow down due to increasing ability to retain water in biopolymer-treated soil. In order to apply biopolymer to river embankment, it is necessary to examine the effects of biopolymers on a wide range of plant species in river embankment.

• Journal of the Korean Geotechnical Society
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• v.31 no.2
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• pp.5-11
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• 2015

Slope stability is affected by duration of precipitation, probable rainfall intensity, unsaturated soil property, and soil strength. The recent analyses of slope stability tend to include unsaturated analysis based on infiltration properties of soil, while researches of unsaturated soil slope tend to include the analysis of deformation and stress distribution of soil over time. However, infiltration property of unsaturated soil slope depends not only on intensity or duration of precipitation, but also on relief and surface condition, which is not considered in status quo. This research uses hydrologic model parameters of soil in order to consider effects of inclination on filtration, and carries out analysis of unsaturated soil slope to confirm the effects according to slope inclination and surface condition. In conclusion, using slope stability analysis, the need to consider infiltration rate according to inclination and surface condition was confirmed even under the same precipitation conditions.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.301-306
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• 2005

Conditions for efficient organogenesis and plant regeneration from Dianthus gratianopol suspension cultured cells were established. Shoot-forming calli of glossy surface, pale green and knobby type were selected from leaf explant-derived calli and were suspension-subcultured every week in CP liquid medium with 1.0 mg/L 2,4-D and 0.5 mg/L BAP. Combinations of 1.0 mg/L 2,4-D and 0.5 mg/L BAP, and 1.5 mg/L 2,4-D and 0.5 mg/L BAP were effective for the induction of regenerative callus from the suspension cultured cell clusters. Multiple shoot primordia were initiated from the green spots of these regenerative callus and formed shoots on MS medium with 1.0 mg/L TDZ and 0.5 mg/L PAA. Shoot regeneration frequency (calli regenerating at least one shoot) was about 87%. For plant regeneration, proliferated shoots were excised and transferred to MS medium with 0.1 mg/L NAA for root initiation after 9 weeks of culture. The regenerants were potted in soil and formed the flowering buds and petals. Also, adventitious shoots were formed from the excised green shoot primordia of regenerative callus and these shoots proliferated successfully and regenerated to whole plants.