• Journal of Korean Society on Water Environment
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• v.25 no.5
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• pp.713-719
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• 2009

A natural wetland in the Nakdong River basin which effectively removes non-point source pollutants was investigated for 2 years to understand wetland topography, vegetation types, and water quality characteristics. The water depth of the natural wetland was in the range of 0.5~1.9 m which is suitable for the growth of non-emergent hydrophytes. The wetland has a high length to width ratio (3.3:1) and a relatively large wetland to watershed area ratio (0.057). A broad-crested weir at the outlet increases the retention time of the wetland whose hydrology is mainly dependent on storm events. The concentrations of dissolved oxygen in the growing season and the winter season showed anoxic and oxic conditions, respectively. Diurnal variations of DO and pH in the growing season were also observed due to weather change and submerged plants. COD and TP concentrations were low in the winter season due to low inflow rate and increased retention time. Increased TP concentrations in the spring season were caused by degradation of dead wetland plants. Nitrogen in the wetland was mostly in organic nitrogen form (>75%). During the growing season, ammonium concentration was high but nitrate nitrogen concentration was low, possibly due to anoxic and low pH conditions which are adverse conditions for ammonificaiton and nitrification. The results of this study can be used as preliminary data for design, operation, monitoring and management of a constructed wetland which is designed to treat diffuse pollutants in the Nakdong river watershed.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.4
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• pp.310-317
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• 2016

This study aimed to evaluate the nutrient load balance from rice paddy fields with different topographies, alluvial plain and local valley. Continuous monitoring from May to September, 2013 was conducted for water quantification and qualification from alluvial plain in Yeoju region (32 ha) and local valley in Jincheon region (24 ha). The discharge rates of T-N from the alluvial plain were 57.2, 5.84, 22.7, and $5.20kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-N loads were 34.6, 4.73, 21.1, and $4.15kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In contrary, the T-P loads from the alluvial plain were 2.23, 2.22, 2.54, and $0.41kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. In case of local valley, T-P loads were 1.44, 1.57, 1.82, and $0.34kg\;ha^{-1}$ for irrigation, precipitation, drainage, and percolation, respectively. The nutrient contents in drainage water were influenced by the amount of waters, rainfall, and surface drainage water. The Pearson correlation analysis showed that rainfall was significantly correlated with nutrient loads from July to August due to the amount of runoff in local valley paddy field, and irrigation was related with nutrient loads of drainage from July to August. This study showed that paddy rice farming in alluvial plain and local valley might be beneficial to water quality protection.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.236-241
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• 2011

Soil microbial diversity was responsible for a strong effect on the chemical properties of orchard soils. This study evaluated a relationship between soil chemical properties and soil microbial diversities at 25 sites in orchard soils in Gyeongnam Province. The average nutrients in the orchard soils were 2.6 times for available phosphorous, 2.3 times for exchangeable potassium and 1.3 times for exchangeable calcium higher compared to recommend concentrations in the orchard soils. Contents of available phosphorous and organic matter in the inclined piedmont soils were higher than those in the other topographical soils (p<0.05). Populations of fungi and fluorescence Pseudomonas sp. in the silt loam soils were significantly higher than those in the sandy loam soils (p<0.05). In principal component analysis of chemical properties and microbial populations in the upland soils, our findings suggested that population of bacteria should be considered as potential factor responsible for the clear orchard soils differentiation. The soil organic matter was significantly negative correlation with population of bacteria whereas was positive correlation with population of fungi in orchard soils.

• Journal of Korea Water Resources Association
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• v.51 no.3
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• pp.221-233
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• 2018

Recently, the flood damage by the localized heavy rainfall and typhoon have been frequently occurred due to the climate change. Accurate rainfall forecasting and flood runoff estimates are needed to reduce such damages. However, the uncertainties are involved in guage rainfall, radar rainfall, and the estimated runoff hydrograph from rainfall-runoff models. Therefore, the purpose of this study is to identify the uncertainty of rainfall by generating a probabilistic radar rainfall ensemble and confirm the uncertainties of hydrological models through the analysis of the simulated runoffs from the models. The blending technique is used to estimate a single integrated or an optimal runoff hydrograph by the simulated runoffs from multi rainfall-runoff models. The radar ensemble is underestimated due to the influence of rainfall intensity and topography and the uncertainty of the rainfall ensemble is large. From the study, it will be helpful to estimate and predict the accurate runoff to prepare for the disaster caused by heavy rainfall.

• Journal of the Korean Institute of Landscape Architecture
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• v.33 no.2 s.109
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• pp.16-31
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• 2005

This study was carried out to design a bridge-type ecological corridor plan in a forested neighborhood park affected by road construction in Dongjak-gu, Seoul. In order to study the site conditions, we analyzed topography, ecosystem structure, and user behavior and trail use. Existing vegetation was classified into 12 types. Based on a vegetation analysis, the Populus albaglandulosa and Robinia pseudoacacia communities, where planted species are dominant, were distributed extensively in the southern forest area. Planted areas with a single-layer structure of Korean landscape woody plants and Robinia pseudoacacia communities with a single-layer structure were distributed extensively in the northern forest and water-supply area. Based on a study of 28 quadrats, the similarity index between the multi-layer plant communities distributed in the southern forest and the single-layer planted areas was low. Twenty-four species of wild birds(355 individuals) were found in the survey area, including nine interior species and three urban species. The study of user behavior and numbers showed most users were walkers and few users were observed in the southern forest while most users were observed in the northern forest and water supply area. We selected some wild birds as model species to represent migrating species believed to use this park as an ecological corridor during migration. We suggested the new park plan include the following: improvement of vegetation structure for wildbird migration and habitat, connection of park trails for users and presentation of a landscape linked to nature.

• Journal of architectural history
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• v.12 no.1 s.33
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• pp.43-58
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• 2003

This study is to analyze spatial structure of Eupchi(邑治) on Chungchong province with Chungchong-do regional maps(忠淸道地方地圖) and Eupjis(邑誌, topography) being compiled in the late Chosun dynasty. According to the analysis of it in this study, we make conclusions as follows; 1. Gunhyeon(郡縣) which had been Eupseong(邑城) on Chungchong-do in Chosun dynasty was 13 provinces, and the construction of Eupseong was the coast Eupseong built for the purpose of defense and military Eupseong built at Byeongyeong(兵營) and Geojin(巨鎭). And a measure used In the construction of a castle was Pobaekcheok(布帛尺) used to survey a frontier defence in Chosun dynasty, also Jucheok(周尺) or Yeongjocheok(營造尺) could be assumed to be wide use at that time. 2. Eupchi of Chungchong-do Gunhyeon was almost disposed to the south direction, also had been Jinsan(鎭山) safeguarding it. With relation to Jwahyang(坐向) and Jinsan, its Jinsan and Myeongdang-cheon(明堂川) match each other in location of Eupchi, as it get Jinsan sat, and take main river in front of it. And provincial government office to be the center of a Eupchi is organized into Gaeksa(客舍), Dongheon(東軒), Naea(內衙), Hyangcheong(鄕廳), and practical business facilities, Jakcheong(作廳) or Jangcheong etc., the others is composed for the use of support of those. 3. In most Eupchi in Chungchong province, the layout Sajikdan(社稷壇) and Yeodan(礪壇) was gone with a principle as they were disposed in the west and the north with Eupchi. Seonghwangdan(城隍壇) and Munmyo(文廟) was built in defiance of a principle, as a condition of province. Jangsi(場市) of Eupchi was opened in front of government office or Gaeksa, and the Gunhyeon which had Eupseong was established in the inside and outside of Eupseong.

• Journal of Ecology and Environment
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• v.29 no.2
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• pp.113-124
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• 2006

Landscape structure, habitat types, vegetation structure and biodiversity in the Bokha stream chosen as a reference stream were investigated to get ecological information necessary for restoration of urban stream degraded by excessive artificial interference. Landscape structure showed a slight change between before and after flooding. Habitat types of nine sorts were identified based on ecological information obtained from field survey such as micro-topography, hydrological characteristics, disturbance regime, and so on. Each habitat holds specific organisms to each site. Consequently, the number of plant communities, and species of benthos and fish increased as the kinds of habitat type increase. Ordination of habitat types based on vegetation, benthos, and fish data reorganized them into three groups of pool types of two kinds depending on whether they are connected to the water course or not and riffle one. Vegetation showed different stratification and species composition depending on topographical position in relation to disturbance cycle. Based on the results from this study, relationship between environmental heterogeneity and biodiversity was discussed and a restoration plan was suggested in a viewpoint of vegetation.

• Journal of Environmental Science International
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• v.24 no.11
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• pp.1513-1523
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• 2015

In order to clarify the characteristics of PM10 in coastal and inland cities and their variation statistical analysis were carried out using environmental and meteorological data observed at Busan and Daegu metropolitans during 4 year from 2010. Averaged PM10 concentration was higher in industrial area than any other land-use sites, and its maximum value reach on over $50{\mu}g/m^3$ at Jangrim site in Busan. Temporal and spatial variations of PM10 concentration in Busan were more sharply, since topograph and mesoscale wind pattern in Busan is more complicated than those in Daegu. Correlation of PM10 concentrations between sites within Daegu appeared strongly and maximum values $R^2$ is about 0.8. This indicate that because wind pattern induced by mesoscale forcing in Daegu are well unified, the variation of PM10 concentration tends to be similar in all sites within Daegu. However, due to complicate wind pattern induced by topography and coastal line, PM10 correlation of sites within Busan was weaker in comparison with in Daegu. And correlation of PM10 at same lane-use in Busan and Daegu tend to be related to the intensity of meteorological forcing, which can decide the intensity of wind pattern.

• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.147-154
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• 2018

PURPOSE. This study was performed to evaluate the osteogenic potential of 3mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) and niobium oxide containing Y-TZPs with specific ratios, new (Y,Nb)-TZPs, namely YN4533 and YN4533/Al20 discs. MATERIALS AND METHODS. 3Y-TZP, YN4533 and YN4533/Al20 discs (15 mm diameter and 1 mm thickness) were prepared and their average surface roughness ($R_a$) and surface topography were analyzed using 3-D confocal laser microscope (CLSM) and scanning electron microscope (SEM). Mouse pre-osteoblast MC3T3-E1 cells were seeded onto all zirconia discs and evaluated with regard to cell attachment and morphology by (CLSM), cell proliferation by PicoGreen assay, and cell differentiation by Reverse-Transcription PCR and Quantitative Real-Time PCR, and alkaline phosphatase (Alp) staining. RESULTS. The cellular morphology of MC3T3-E1 pre-osteoblasts was more stretched on a smooth surface than on a rough surface, regardless of the material. Cellular proliferation was higher on smooth surfaces, but there were no significant differences between 3Y-TZP, YN4533, and YN4533/Al20. Osteoblast differentiation patterns on YN4533 and YN4533/Al20 were similar to or slightly higher than seen in 3Y-TZP. Although there were no significant differences in bone marker gene expression (alkaline phosphatase and osteocalcin), Alp staining indicated better osteoblast differentiation on YN4533 and YN4533/Al20 compared to 3Y-TZP. CONCLUSION. Based on these results, niobium oxide containing Y-TZPs have comparable osteogenic potential to 3Y-TZP and are expected to be suitable alternative ceramics dental implant materials to titanium for aesthetically important areas.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2B
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• pp.109-119
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• 2011

In this study, the flow characteristics of Han River Estuary were investigated by using a two-dimensional numerical model according to the assumption of shift and modification of the Shingok submerged weir. The two-dimensional analysis has contributed to our understanding of the hydraulic effects induced by shift of the weir on the topography, especially wetlands. The tide and flow discharge of 2007 were adopted as an input data for the simulation. The tidal data contained both spring and neap tide, and the flow discharge condition was divided into monsoon and normal seasons. The boundaries of this study were Hangang Bridge, Tongil Bridge, and Yu island. The simulation results showed that influence area of seawater changed depending on the weir shift, and the water level at particular station fluctuated according to the condition of tide and flow discharge.