• Journal of Korean Society on Water Environment
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• v.28 no.2
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• pp.320-331
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• 2012

A combination system of catch canal and constructed wetland was designed and suggested to improve water quality in gagricultural region of lower Dong-jin river basin. In order to evaluate an water quality improvement efficiency of the designed combination system, the NPS-WET model was applied in this study. Simulation result of the NPS-WET shown that the nutrient load removal rate of constructed wetland was BOD, T-N, T-P and SS was 30.7~39.0%, 46~60%, 40.7~57.0% and 68.2~74.7%, respectively. Nutrients reduction of constructed wetland was higher in growing season than winter season because vital activity of microorganism, macrophyte and algae was augmented with high air and water temperature. Effluents from constructed wetland can affect water-quality of catch canal drains, especially, water-quality on junction point to Dong-jin river. Water-quality improvement in low-flowed catch canal (Un-san) was more significant than in high-flowed catch canal (Won-pyeong). In conclusion, a feasible design of constructed wetland is necessary to treat large quantity of receiving water. The NPS-WET is useful tool for assessing water-quality improvement efficiency using constructed wetland.

• Journal of Wetlands Research
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• v.23 no.4
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• pp.372-380
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• 2021

Non-point source pollutants and high-concentration livestock wastewater are reported as major factor of water pollution in water system and wet-land. So, LID is suggested as a method to manage of them. wet-lands is presented as effective method for management of NPS from agriculture and livestock farm area based on various NPS reduction mechanism. In this research, the application of wet-lands was evaluated based on monitoring and modeling of agriculture and livestock farm in J city, Jeollabuk-do. As a resutl, EMC during rainfall event was found to be about 27 times higher than dry season based on a BOD. indicating that the management of non-point pollutants is urgent. Modeling-based wet-land reduction efficiency was BOD 57.5%, TN 48.9% and Tp 64.2%. However, removal efficiency of wet-land tends to decrease during the winter and large amounts of rainfall runoff occur, it is necessary to manage of wet-land. Based on the results of this research, wet-land could be proposed as an alternative to stable management of NPS in agriculture and livestock farm area.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.4
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• pp.25-31
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• 2012

In the synthesis of nanoparticles (NPs) via wet chemical reduction using tin(II) acetate precursor, the effects of green reducing agents (sugar) and a capping agent (gelatin) on the formation of NPs were analyzed as functions of synthesis conditions and time. When glucose was used as the reducing agent, it was observed that irregular chainlike shapes, aggregates of NPs, were formed during the synthesis at $70-110^{\circ}C$. The NPs were determined as $SnO_2$ from the fast Fourier transform (FFT) pattern. In the synthesis at $110^{\circ}C$ by using sucrose, fine spherical NPs of ~10 nm in diameter were formed after the synthesis time of 3 h. As the time increased to 9 h, the chainlike NP aggregates besides irregularly aggregated spherical NPs were also formed locally. However, the chainlike NP aggregates were only observed when the synthesis was conducted at $130^{\circ}C$. The spherical NPs and chainlike NP aggregates were analyzed to be pure Sn and $SnO_2$, respectively.

• Journal of Environmental Impact Assessment
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• v.25 no.4
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• pp.248-260
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• 2016

This study was aimed to assess the effect of diverse pollutants control measures suggested in the Chuso basin and its upstream of So-oak stream watershed where are the most concerned areas on the control of algal bloom occurring in Daecheong Reservoir. The control measures were classified as watershed measures and in-reservoir measures, and their effects were simulated using a two-dimensional hydrodynamic and water quality model. The watershed measures were made up of 1) point sources control, non-point sources control, and their combinations. The in-reservoir measures were supposed to treat sediment at Chuso basin and to install a phosphorus elimination plant (PEP) at the end of So-oak stream. The results showed that the effect of each measure was influenced by the hydrological condition of the year. In wet year, as the contribution of non-point sources increased, the non-point source control measures (NPS1~NPS4) showed more effective compared to other measures, while, the PEP system to eliminate phosphorus from So-oak stream showed better performance in dry year. In particular, the scenario of NPS1, in which all livestock manures were collected and treated but only chemical fertilizers (NPS1) were used for agriculture fields, showed the best performance for the control of algal bloom in Chuso basin among the watershed measures.

• Journal of Wetlands Research
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• v.19 no.4
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• pp.393-402
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• 2017

This study was designed to provide basic information for an effective wetland design by analyzing the correlation between wetland size and water quality improvement effect in regard to an artificial wetland inside the Biopark Basin by means of applying the modelling technique. It is expected that this study will contribute to a rational design, operation and management of the artificial wetland in the basin. The following conclusions are obtained through the results and discussion of this study. The results of respective design scenarios that expanded the size of the artificial wetlands in the range of 0-100 % showed that when the wetland is 'expanded 75 % compared with the existing size', water quality improved best compared with the design criteria of 'the current operation of the existing size'. The improved data are: 66.7 % in BOD5, 69.9 % in TSS, 64.7 % in T-N, 85.5 % in T-P and 51.8 % in Chl-a. In particular, with the exception of Chl-a, water quality improvement stood out in the quality items in summer among the four seasons. And that there in no direct relationship between facility scale and water quality improvement.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.413-419
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• 2010

A silica mine monitoring was conducted from March to December in 2008 to measure rainfall, runoff amounts and pollution loads. A total of 13 rainfall-runoff events were measured and analyzed with respect to runoff ratio, pollutant concentration and load, and initial flush. Over rainfall-runoff events, 95% confidence range of SS concentration was 942.5~2,056.2 mg/L. Other measured water quality indices also showed relatively large variation. This wide concentration variation was thought to be caused by the bare working ground of the mine that was used to store, process and transport the mined silica. Total pollution load of the 13 rainfall-runoff events was SS 17,901 kg/ha, $COD_{Cr}$ 160.9 kg/ha, $COD_{Mn}$ 111.24 kg/ha, BOD 79.6 kg/ha, T-N 13.8 kg/ha, T-P 3.5 kg/ha, and TOC 39.3 kg/ha. Initial flush was not well observed except SS. Very high SS concentration and load was occurred when rainfall was large. Therefore, it was recommended to manage the bare ground not to discharge excessive pollutants during wet days by covering the ground or constructing runoff treatment systems such as a sediment basin.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.80-89
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• 2017

Researches about NPS(Non-point Pollution Source) reduction have been widely carried out in recent years. A pilot channel-type constructed wetland (wet swale) was constructed in Rongyin area to treat stormwater generated from a green house agro-land of 22.7 ha. From 2006 to 2008, monitoring was conducted to evaluate its performance on the removal effect for organic pollutants as well as nutrients. Totally, sampling trips of 17 rainfall events were made and they covered most types of storm events in Korea. The channel-type constructed wetland have average removal efficiencies of 78.3~92.0%, 56.4~66.1%, 28.2~45.5% and 50.6~66.4% for SS, COD, TN and TP, respectively. According to four methods for estimating the removal efficiency, the average efficiencies of TSS, COD, TN and TP are 86.0%, 60.1%, 30.1% and 53.5%, respectively. From 2006 to 2008, annual efficiency improved due to infiltration potential increase. It was found that most of the pollutants removed in this channel type of wetland was particulate solids bound pollutants, which is assumed fact that it lacks of physico-chemical treatment conditions which are commonly observed in the retention type of constructed wetlands.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.3025-3032
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• 2012

Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT@C) have been fabricated by a two step polymerization method. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were prepared with a wet-type beadsmill method. A polymer, which is easily removable by a thermal treatment (intermediate polymer) was polymerized on the outer surfaces of Si-CNT nanocomposites. Subsequently, another polymer, which can be carbonized by thermal heating (carbon precursor polymer) was incorporated onto the surfaces of pre-existing polymer layer. In this way, polymer precursor spheres containing Si-CNT nanohybrids were produced using a two step polymerization. The intermediate polymer must disappear during carbonization resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT@C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT@C microcapsules were measured with a lithium battery half cell tests.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.3
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• pp.91-101
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• 2012

This study is to assess the runoff characteristics of nonpoint source pollution loads for Jecheon and Jangpyeong stream watersheds located in the upstream of Chungju lake. The SWAT (Soil and Water Assessment Tool), a physically based distributed hydrological model was calibrated and verified using 5 years (2006 to 2010) streamflow and water quality data. The Nash-Sutcliffe model efficiency for streamflow was 0.60~0.92 and the determination coefficients for sediment, Total Nitrogen (T-N), and Total Phosphorous (T-P) were 0.53~0.71, 0.51~0.91 and 0.38~0.85 respectively. The results showed that the Sediment, T-N, and T-P of Jangpyeong stream were 40.0~60.9 %, 34.8~64.1 % and 76.5~83.9 % higher than Jecheon stream watershed during wet days. The results evaluated high NPS loads at Jangpyeong stream because the percentage of urban and upland crop cultivation area Jangpyeong stream watershed was higher than Jecheon stream watershed.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.1
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• pp.97-105
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• 2008

Nitrogen budgets in Korea in 2005 were estimated using a mass balance approach. Major nitrogen fluxes were divided into three sections: cities, agricultural area, and forest. Nitrogen inputs were chemical and biological fixation, dry and wet deposition, imported food and feed, while crop uptake, volatilization, denitrification, leaching, runoff, and forest consumption were nitrogen outputs. Non-point source(NPS) pollution budgets were also estimated by mass balance approach. Annual total nitrogen inputs budgets were 1,442,254 ton$\cdot$yr$^{-1}$, and outputs were 814,415 ton$\cdot$yr$^{-1}$. Approximately 19.4% of nitrogen input leaked to river and seawater as NPS pollution. It contains nitrogen input 21 percent more than the previous research in 2002. Especially the change of government plans affect nitrogen budget. As a result, in the output field, the whole nitrogen amount due to landfill reduce from 20 percent to less than 1 percent.