• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.767-776
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• 2014

Changes in climate have largely increased concentrated heavy rainfall, which in turn is causing enormous damages to humans and properties. Floods are one of the most deadly and damaging natural disasters known to mankind. The flood forecasting and warning system concentrates on reducing injuries, deaths, and property damage caused by floods. Therefore, the exact relationship and the spatial variability analysis of hydrometeorological elements and characteristic factors is critical elements to reduce the uncertainty in rainfall-runoff model. In this study, grid resolution depending on the topographic factor in rainfall-runoff models presents how to respond. semi-distribution of rainfall-runoff model using the model GRM simulated and calibrated rainfall-runoff in the Gamcheon and Naeseongcheon watershed. To run the GRM model, input grid data used rainfall (two event), DEM, landuse and soil. This study selected cell size of 500 m(basic), 1 km, 2 km, 5 km, 10 km and 12 km. According to the resolution of each grid, in order to compare simulation results, the runoff hydrograph has been made and the runoff has also been simulated. As a result, runoff volume and peak discharge which simulated cell size of DEM 500 m~12 km were continuously reduced. that results showed decrease tendency. However, input grid data except for DEM have not contributed increase or decrease runoff tendency. These results showed that the more increased cell size of DEM make the more decreased slope value because of the increased horizontal distance.

• Journal of Korea Water Resources Association
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• v.46 no.6
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• pp.655-666
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• 2013

Lately, intensity and frequency of natural disasters such as flood are increasing because of abnormal climate. Casualties and property damages due to large-scale floods such as Typhoon Rusa in 2002 and Typhoon Maemi in 2003 rapidly increased, and these show the limits of the existing disaster prevention measures and flood forecasting systems regarding irregular climate changes. In order to efficiently respond to extraordinary flood, it is important to provide effective countermeasures through an inundation model that can accurately simulate flood inundation patterns. However, the existing flood inundation analysis model has problems such as excessive take of analysis time and accuracy of the analyzed results. Therefore, this study conducted a flood inundation analysis by using the Gerris flow solver that uses quadtree grid, targeting the Baeksan Levee in the Nakdong River Basin that collapsed because of a concentrated torrential rainfall in August, 2002. Through comparisons with the FLUMEN model that uses unstructured grid among the existing flood inundation models and the actual flooded areas, it determined the applicability and efficiency of the quadtree grid-based flood inundation model of the Gerris flow solver.

• Journal of the Korean Chemical Society
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• v.62 no.3
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• pp.181-186
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• 2018

Nitrosamines are the nitrosocompounds which are produced by nitrosation reactions of the secondary amine and nitrite, and has been found to be produced through the vulcanization process during the production of rubber products Recently, nitrosamines have been detected in rubber products and become a major topic. Condoms are disposable medical devices, so safety is important because they come into direct contact with the skin and mucous membranes. In this study, we developed an analytical method for nitrosamines in condoms by applying ISO 29941 method. The samples were eluted by distilled water, and target compounds were extracted by liquid-liquid extraction with dichloromethane. And then after concentrated, and quantitatively analyzed by LC-MS/MS. The accuracies of the analytical method were ranged from 85.8 to 108.7%, precisions were lower than 11.5%, and the detection limits were from 0.11 (NDPA and NDBA) to 0.48 (NPYR) ng/mL. Among the 31 condom samples, NDBA was detected from 2 cases by extraction of distilled water, and NDMA were detected from 1 case, NDEA from 4 cases and NDBA from 26 cases by extraction of artificial saliva (pH 4.5). The total amount of nitrosamines in all samples were less than $500{\mu}g/kg$.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.327-333
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• 1993

A method was developed for the determination of trace elements in seawater by precipitate flotation preconcentration and subsequent flame atomic absorption detection. In order to quantitatively coprecipitate trace ions such as Cd(II), CuI(II), Fe(III), Mn(II), Pb(II) and Pd(II), 2.0 ml of 1.0M cerium(III) solution was added to 1.0l of seawater and the pH was adjusted to 9.5 with 5.0 M sodium hydroxide solution while stirring with a magnetic stirrer. The precipitate was floated with the aid of surfactant solution (1.0 ml of 0.3% sodium oleate) by bubbling nitrogen gas through a porous (No. 4) fritted glass disk. The floats was collected in a small Erlenmeyer flask by suction. The washed precipitate was dissolved in 8.0 M nitric acid and marked with deionized water in the volumetric flask of 10.0 ml. The analyte was determined by measuring the atomic absorbances in 100-fold concentrated solution. Above all analytes in Kangnung (East Sea) and Kanghwado (West Sea) sea waters were found to be under the detection limit of this method. The recoveries of over 92% for all analytes spiked into seawater samples showed that this method was applicable to the analysis of real seawater.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.428-435
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• 2015

Constructed wetlands (CWs) have been accepted as an attractive and economic alternative to a variety of pollution control and provided potentially valuable wildlife habitat in urban and suburban areas, as well as esthetic value within the local natural environment. CWs are known eco-friendly technology to solve the problem of the climate change and urbanization issues. Numerous studies have been published on the various aspects of a CW. However, there are current limitations about the CW operations such as few design guidelines, poor performance results regarding the simple construction. Therefore, the objective of this research was to suggest an appropriate design and maintenance guidelines for a CW by thorough investigation of site monitoring results. The research also concentrated in redefining and reclassifying CWs, based on literatures made by the Ministry of Environment (MOE) and other organizations. Investigation at 43 CWs in Korea was performed by using collected data and by performing site survey from 2013 to 2014. Based on the results, the best practices among the investigated CWs provided water treatment, wildlife habitat, environmental education, and leisure. Also these CWs conducted a regular maintenance such as vegetation, sediment dredging and cleaning of facilities. Results obtained are intended for use by academics and any organizations involved in CW management.

• Journal of Korea Water Resources Association
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• v.43 no.3
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• pp.245-256
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• 2010

We study the basic theory and applicability of the WQUAL block in the FFC2Q model and the characteristics of non-point pollutant loads during the early stage of runoff. Study is also performed on selection of the values of the related parameters and their effect on the simulation results. FFC2Q simulation results are compared for verification with the measured data for three rainfall events in the Gunja Subbasin and found to be similar to the measured data in peak-flows, total runoff volumes, total loads, peak concentrations and times of peak concentration. This model thus shows results very close to those applying the SWMM and MOUSE models, even though it uses simplified input data. Related to rainfall distribution, under the condition of Huff 1st quartile distribution the pollutant loads occurred earlier than under other conditions, and in the early stage of rainfall the BOD and COD loads increased faster than the SS loads. The NPS loads were concentrated in the early stage of rainfall and finally reached total loads, so the rainfall after that could not contribute so much to the NPS loads.

• Journal of Korea Water Resources Association
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• v.43 no.4
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• pp.409-419
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• 2010

In this study, for the purpose of analyzing the characteristics of Korean hydrologic weather parameters, 9 hydrologic weather parameters data such as annual precipitation, annual rainy days, annual average relative humidity, annual average temperature, annual duration of sunshine, annual evaporation, annual duration of precipitation, annual snowy days and annual new snowy days are collected from 63 domestic meteorological stations that has the hydrologic weather parameters records more than 30 years. And the basic characteristics of hydrologic weather parameters through basic statistics, moving average and linear regression analysis are perceived. Also trend using the statistical methods like Hotelling-Pabst test and Mann-Kendall test about hydrologic weather parameters is analyzed. Through results of basic analysis, moving average and linear regression analysis it is shown that precipitation is concentrated in summer and deviation of precipitation for each season showed significant difference in accordance with Korean climate characteristics, besides the increase in annual precipitation and annual average temperature, annual average relative humidity and annual duration of sunshine reduction and annual rainy days is said to increase or decrease. The results of statistical analysis of trend are summarized as trend commonly appeared in annual average relative humidity and annual average temperature. and annual precipitation, annual rainy days and annual duration of sunshine showed different results according to area.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.249-255
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• 2006

The optimum culture conditions for the ice nucleating activity and the cell growth of Xanthomonas translucens KCTC 2751 were investigated. The optimum initial pH and temperature for the cell growth and the ice nucleating activity were 6.5 and $25^{\circ}C$, respectively. The optimum culture medium for the ice nucleating activity was composed of 1.0% maltose, 1.4% yeast extract, 0.8% digested of gelatin, and 0.03% KCI in distilled water. Freezing operations carried out on distilled water showed that the degrees of supercooling were $-7.90^{\circ}C$ without ice nucleators, $-1.56^{\circ}C$ with silver iodide as a commercial ice nucleator, and $-1.36^{\circ}C$ when Xanthomonas translucens KCTC 2751 were added. During progressive freeze-concentration assays, the addition of Xanthomonas translucens KCTC 2751 led to lower saccharose concentrations in the crystals, while the cells led to higher saccharose concetrations in the concentrated phase.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.8-16
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• 2004

The industrialization of central Europe more than 100 ago marked the beginning of densely concentrated buildings in quickly growing cities. A cheap type of roofing material of that time was tar. But it was dangerous because it was high inflammable. Then some roofer had a splendid idea. They used sandy material as a final layer atop the impermeable tar layer. These roofs were much more fire resistant than the typical roofs. In this sandy layer some plant species began to grow spontaneously. This was the beginning of the green roof history of modern Europe. A number of these green roofs survived both world wars. In the early 80's in Berlin alone, 50 such buildings existed and they continued to be waterproof until the present day. Since the 1992 Earth Summit of 1992 in Rio de Janeiro(http://www.johannesburgsummit.org/html/basic_info/unced.html) the term "sustainable development" became of central interest of urban designers. In city regions green roofs had become synonymous with this term. With a small investment, long-lasting roofs can be created. Further back in history, more exciting examples of green roofs can be found. The hanging gardens of antiquity are well-known. There are also green roofs built as insulation against cold and heat all over the world. For over 20 years, roof greening in central Europe has been closely examined for various reasons. Roof greening touches several different disciplines. Of primary interest is the durability of the roofs. But ecologists are also interested in green roofs, for instance in biodiversity research. The beneficial effect of greening on water proofing was also proven. For some time, the issue of fire protection was investigated. According to tests, green roofs received a harsh careful rating. Their fire protective property is considered similar to that of tile roofs. Another recent impulse for the green roof movement in Germany has come from the evident improvement of storm water retention and the reduced burden on the sewer system. The question of whether and how much energy green roofs can save has become an urgent question. The state of the research and also various open questions from a central European point of view will be discussed in the context of international collaboration. Apart from academic considerations, those who involve themselves in this issue take a predominantly positive view of the numerous existing green roofs in Germany. In some cities, green roofs are the typical construction technique for new buildings. A few outstanding examples will conclude this review. In Germany, about 20 companies, some of which operate internationally, specialize in green roof consulting. Learning from each other in an open-ended way with respect to different construction techniques and applications in various climatic regions can only be accomplished through such international collaboration as is taking place here.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3469-3476
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• 2015

The Korea Academia-Industrial cooperation Society. The Korea Academia-Industrial cooperation Society. In Korea, the territory has east high west low type and the rainfall is concentrated in the summer season. A nation having these topography and precipitation condition like Korea has to basically needs support of hardware alternatives. However, the right places decrease gradually and the resistance of the public opinion for national water resources policy stiffens gradually. The climate change has an effect in water resources fields and has a close relation. In the present study, therefore, future inflow of Miryang multipurpose dam basin is estimated by using SWAT model applied RCP 4.5 and 8.5 scenarios of "Korea Meteorological Administration" and considering the results, the future direction is purposed to operate the dam. As a result, the rainfall pattern is changed from traditional peak form to flat form. The dam operation rule in accordance with changing precipitation pattern has to be modified from the conventional operation rule and a new plan has to be established to meet a situation.