• Journal of architectural history
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• v.19 no.5
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• pp.81-98
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• 2010

In the middle of the 8th century, we met the new high-rise building, the 7th storied wooden pagodas in 'Kokubunji' in Japan. I tried to analyze and study this building to show how the wooden pagoda had changed itself because of appearance of new style. The conculusions are as follows; 1. The construction of the foundation was mainly composed namely 'Panchuk'. It was proceeded by two ways. One is the earthen-digging, laying foundations named 'Gulkwangpachuk' and the other is simply laying foundation named 'Jisangpanchuk'. In that period, due to the progress of the technique, we assumed that the main stream is 'Jisangpanchuk'. 2. The elevation of base was mostly the single foundation from archaeological study. The material was stone. The middle case of pagoda had the base of tile-roofed. We knew the just one pagoda had the base of brick, but that was not main stream. 3. The new device had appeared in the central base stone. It was the stone point. But in that period the existing method, a hole style and the new style was used in the central base stone. This fact is showed that the central government was not hold the reigon(it names 'Kook') in the respect of the technique. 4. The plan scale is classified of 3 group. As a result, the first body is larger, the main-unit and the sub-unit is a equal unit. But smaller, the length of main-unit is longer than the one of sub-unit. And the very small pagoda was build in that period.

• Journal of Soil and Groundwater Environment
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• v.27 no.2
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• pp.61-75
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• 2022

This study evaluated the potential threat of agricultural and human activities to groundwater in the Noseong stream watershed, a typical agricultural area, through hydrogeochemical characteristics and microbial community analyses. The groundwater in the study area was Ca-SO₄ and Ca-HCO₃ types alluvial aquifer mainly used for agricultural and living purposes, and contained high levels of NO₃^- and Cl^- ions generated from anthropogenic sources such as fertilizer, livestock wastewater, and domestic sewage. Proteobacteria was most abundant in all samples with an average of 46.1% while Actinobacteria, Bacteroidetes, and Cyanobacteria were dominant on an occasional basis. The prevalence of aerobic bacteria such as the genus Mycobacterium, Flavobacterium, and Sphingomonas suggests that groundwater was well connected with the surface layer. The potential pathogen Mycobacterium was detected in most samples, and other pathogenic bacteria were also widely distributed, indicating the vulnerability to contamination. Therefore, an integrated management system is required to secure the sustainable use of groundwater in agricultural areas with high groundwater dependence.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.3
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• pp.164-169
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• 2004

A spatial interpolation scheme incorporating local geographic potential for cold air accumulation (TOPSIM) was used to test the feasibility of operational frost warning in Chatancheon basin in Yeoncheon County, where the introduction of new crops including temperate zone fruits is planned. Air temperature from April to June 2003 was measured at one-minute intervals at four locations within the basin. Cold-air accumulation potentials (CAP) at 4 sites were calculated for 3 different catchment scales: a rectangular area of 65 x 55 km which covers the whole county, the KOWACO (Korea Water Corporation) hydrologic unit which includes all 4 sites, and the sub-basins delineated by a stream network analysis of the digital elevation model. Daily minimum temperatures at 4 sites were calculated by interpolating the perfect prognosis (i.e., synoptic observations at KMA Dongducheon station) based on TOPSIM with 3 different CAPs. Mean error, mean absolute error, and root mean square error were calculated for 45 days with no precipitation to test the model performance. For the 3 flat locations, little difference was detected in model performance among 3 catchment areas, but the best performance was found with the CAPs calculated for sub-basins at one site (Oksan) on complex terrain. When TOPSIM loaded with sub-basin CAPs was applied to Oksan to predict frost events during the fruit flowering period in 2004, the goodness of fit was sufficient for making an operational frost warning system for mountainous areas.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1041-1052
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• 2022

This study is to estimate the optimal ecological flow and analysis the spatial distribution of fish habitat for Andong dam downstream reach (4,565.7 km²) using PHABSIM (Physical Habiat Simulation System) and River2D. To establish habitat models, the cross-section informations and hydraulic input data were collected uisng the Nakdong river basic plan report. The establishment range of PHABSIM was set up about 410.0 m from Gudam streamflow gauging station (GD) and about 6.0 km including GD for River2D. To select representative fish species and construct HSI (Habitat Suitability Index), the fish survey was performed at Pungji bridge where showed well the physical characteristics of target stream located downstream of GD. As a result of the fish survey, Zacco platypus was showed highly relative abundance resulting in selecting as the representative fish species, and HSI was constructed using physical habitat characteristics of the Zacco platypus. The optimal range of HSI was 0.3~0.5 m/s at the velocity suitability index, 0.4~0.6 m at the depth suitability index, and the substrate was sand to fine gravel. As a result of estimating the optimal ecological flow by applying HSI to PHABSIM, the optimal ecological flow for target stream was 20.0 m³/sec. As a result of analysis two-dimensional spatial analysis of fish habitat using River2D, WUA (Weighted Usable Area) was estimated 107,392.0 m²/1000 m under the ecological flow condition and it showed the fish habitat was secured throughout the target stream compared with Q₃₅₅ condition.

• Journal of Environmental Science International
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• v.18 no.5
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• pp.569-578
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• 2009

Aircraft Measurements of gaseous pollutants($SO_2$, NOx and $O_3$) in the Yellow Sea area, were carried out on 1997-2007. Main measurement site in 124$^{\circ}$-127$^{\circ}$E, 35$^{\circ}$-37$^{\circ}$N (in the Yellow Sea), have been done along the paths classified vertically and zonally. To understand how the air stream affects Long-range transboundary pollutants in Northease Asia (LTP), the tracks of pollutants in northeast Asia have been analyzed by dividing into 6 different regions(regions I-V and L). Compared with Korea's local sources and western north Pacific influenced by the Yellow Sea, when the air stream from region II is dominant, the $SO_2$ concentrations are 3-6times higher. In region II and III, $SO_2$ concentrations are represented highest at 25.0 and 14.7 ppb, respectively. However, in other regions, $SO_2$ concentration was recorderd the highest at 1.1-3.8 ppb, which is 7-15% higher then the highest one over the region II and III. During 1997-2007, the mean amount of incoming pollutants is 0.162 $ton/km{\cdot}hr$ exceeding about 5-times mean amount of outgoing pollutants over the West Sea. During the observed period, the amount of incoming and outgoing $SO_2$ over the Yellow Sea is the highest in winter, at 0.224 $ton/(km{\cdot}hr)$ and 0.120 $ton/(km{\cdot}hr)$, respectively.

• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.452-458
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• 2017

The nitrogen isotope value in both ammonium and nitrate ion were determined at 9 stations during both June and August 2016, in order to understand the origin of DIN at the Han river. ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in 8 stations (CP, SB, MHC, P4, SJ, SBC, P2, SC) were no significant variation. However ${\delta}^{15}N-NO_3$ and ${\delta}^{15}N-NH_4$ values in KK (Kyeongan stream) showed significant different in comparison with 8 stations, with an apparent increase of nitrogen isotope values. These results indicate that antropogenic nitrogen source influence on KK station. Also the ${\delta}^{13}C$ and ${\delta}^{15}N$ isotope ratio of phytoplankton (Diatom and Cyanobacteria) in KK (Kyeongan stream) showed heavier values, compared to other study stations. These results indicate that nitrogen isotope value in phytoplankton effects by different nitrogen source in study sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of dissolved inorganic nitrogen origin in aquatic environments.

• Journal of Wetlands Research
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• v.23 no.3
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• pp.252-259
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• 2021

Numerous valley waters originating from Mt. Mudeung and flowing into Gwangju Cheon flowed into the confluence-type sewage conduit, the Gwangju Cheon became dry and water quality deteriorated. In this study, a method to create a stream was studied by using the valley water of Mt. Mudeung in the Gwangju cheon that flows into the sewage treatment plant as a water source. Flow and water quality surveys were investigated at four points with meaningful flow quantity. As a result, it showed a flow quantity was 105~2,721 m³/day at each point. And the average water quality was BOD₅ 0.3~1.6 mg/L. If a stream with a flow quantity of 1,500 m³/day is created during the dry season and then flows into the Namgwang bridge of Gwangju cheon, it is predicted that there will be improvements in BOD 7.3%, COD 6.5%, T-P 5.8%, and T-N 5.2%. In addition, it was determined that the load on the flow quantity of the sewage treatment plant due to the inflow of valley water would be reduced, the cost of sewage treatment would be reduced, and it would be the basis for BGN construction by creating waterside amenity in the city.

• Clean Technology
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• v.21 no.1
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• pp.68-75
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• 2015

In this study, we investigated the structure and properties of a highly heat conductive metal-ceramic core-shell CoAl₂O₄@Al micro-composite for heterogeneous catalysts support. The CoAl₂O₄@Al was prepared by hydrothermal surface oxidation of Al metal powder, which resulted in the structure with a high heat conductive Al metal core encapsulated by a high surface area CoAl₂O₄ shell. For comparison, CoAl₂O₄ was also prepared by co-precipitation method and also utilized for a catalyst support. Rh catalysts supported on CoAl₂O₄@Al and CoAl₂O₄ were prepared by incipient wetness impregnation and characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), CO chemisorption, and temperature-programmed reduction (TPR). The properties of catalysts were investigated for glycerol steam reforming reaction for hydrogen production at 550 ℃. Rh/CoAl₂O₄@Al exhibited about 2.8 times higher glycerol conversion turnover frequency (TOF) than Rh/CoAl₂O₄ due to facilitated heat transport through the core-shell structure. The CoAl₂O₄@Al and CoAl₂O₄ also showed some catalytic activities due to a partial reduction of Co on the support, and a higher catalytic activity was also found on the CoAl₂O₄@Al core-shell than CoAl₂O₄. These catalysts, however, displayed deactivation on the reaction stream due to carbon deposition on the catalysts surface.

• Food Science of Animal Resources
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• v.35 no.6
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• pp.765-771
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• 2015

The development of a sample preparation method and optimization of the analytical instrumentation conditions were performed for the determination of the vitamin B₁₂ content in emulsified baby foods sold on the Korea market. After removal of the milk protein and fats by chloroform extraction and centrifugation, the vitamin B₁₂ was water extracted from the sample. Following filtration of the solution through a nylon filter, the water-soluble extract was purified by solid-phase extraction using a Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS). The solution eluted from the cartridge was dried under a stream of nitrogen gas and reconstituted with 1 mL of water. The sample solution was injected into an LC-MS/MS system after optimizing the mobile phase for vitamin B₁₂ detection. The calibration curve showed good linearity with the coefficient of correlation (r²) value of 0.9999. The limit of detection was 0.03 µg/L and the limit of quantitation was 0.1 µg/L. The method of detection limit was 0.02 µg/kg. The vitamin B₁₂ recovery from a spiking test was 99.62% for infant formula and 99.46% for cereal-based baby food. The sample preparation method developed in this study would be appropriate for the rapid determination of the vitamin B₁₂ content in infant formula and baby foods with emulsified milk characteristics. The ability to obtain stable results more quickly and efficiently would also allow governments to exercise a more extensive quality control inspection and monitoring of products expected to contain vitamin B₁₂. This method could be implemented in laboratories that require time and labor saving.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.795-798
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• 2002

This paper dispicts the vortical flow characteristics over a delta wing using a computational analysis for the purpose of investigating and visualizing the effect of the angle of attack and fee stream velocity on the low-speed delta wing aerodynamics. Computations are applied to the full, 3-dimensional, compressible, Navier-Stokes Equations. In computations, the free stream velocity is changed between 20m/s and 60m/s and the angle of attack of the delta wing is changed between $16^{\circ}\;and\;28^{\circ}$. For the correct prediction of the major features associated with the delta wing vortex flows, various turbulence models are tested. The standard $k-{\varepsilon}$ turbulence model predict well the vertical flows over the delta wing. Computational results are compared with the previous experimental ones. It is found that the present CFD results predict the vortical flow characteristics over the delta wing, and with an increase in the free steam velocity, the leading edge vortex moves outboard and its streangth is increased.