• Ocean and Polar Research
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• v.33 no.3
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• pp.255-263
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• 2011

The aim of this investigation was to evaluate antioxidant activity of crude extracts from the halophyte Vitex rotundifolia, their solvent fractions, and isolated compounds (1-3). Antioxidant capacity was determined by measuring DPPH radical, and authentic $ONOO^-$ and $ONOO^-$ generated from 3- morpholinsydnonimine (SIN-1) in vitro as well as degree of occurrence of intracellular ROS, NO and GSH in mouse macrophage Raw 264.7 cells. From comparative analysis, MeOH extract, n-BuOH, and 85% aq. MeOH solvent fractions showed significant antioxidant effect in DPPH radical and $ONOO^-$ assay systems. Activity-guided purification of n-BuOH and 85% aq. MeOH fractions led to the isolation of flavonoids 1-3. Among them, compound 1 exhibited excellent antioxidant effect in all bioassay systems tested. On the other hand, compounds 2 and 3 revealed potent inhibitory effect against $ONOO^-$ generated from SIN-1, comparable with the positive control penicillamine.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.403-410
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• 2006

The objective of this study was to evaluate the possibility of sedimentation basin omission when installed hybrid membrane filtration process in the field plant with the capacity of $500m^3/day$ for 11 months in the "G", water purification plant in Seoul. In order to evaluate the possibility of the sedimentation basin omission, we measured the change of DOC by coagulant dosage. Dosage of PAC(power activated carbon) 4mg/L and coagulant($AI_2O_3$ 10%) 1.67mg/L were compatible to meet the water quality. Also according to the experiment without settlement process, optimization G values were determined to be 300/s, 64/s, and 32/s at the mixing tank, the first flocculator and the second flocculator, respectively. The test was performed under the conditions PAC-coagulation-no settlement-MF. As a result, a dosage of 4.0mg/L as PAC and 0.86 to 1.22mg/L as $Al_2O_3$(10%) in the condition of flux of 62.5LMH were determined to keep TMP value less than $1.0kg_f/cm^2$.

• Journal of Environmental Science International
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• v.9 no.2
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• pp.125-129
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• 2000

As one of the fundamental survey to evaluate purification capacity of pollutants at the tidal flat sediments, we studied vertical environmental characteristics in three tidal flat sediments, Chunjangdae, Eueunri and Gyewhado. These are dissmilar to external feature in each other. The results of this study may be summarized as followed; As the results of particle analysis, Eueunri tidal flat fediment located in Keum river estuary consists of 98.98% as silt & clay, Chunjangdae tidal flat sediment located in SeocheonGun consists of 97.99% as sand. And Gyewhado tidal flat sediment located in Saemankeum in Saemankeum area consists area consists of 32.81% as silt & clay and 67.19% as sand. The concentration of organic pollutants(I.L., COD, POC, PON) in Eueunri tidal flat sediment which highly content of silt & clay were 3~4 times higher than others. The concentration of organic pollutants at each layer were slightly increase goes with deepen layer. The linear correlation between I.L. and COD, POC, PON were obtained. Correlation coefficients were in range of 0.821~0.940. Also the correlation between pH and COD, POC, PON were high(>r=0.9). Filteration rate in Chunjangdae tidal flat sediment was 0.01584cm/s as mean value, but the other were almost nothing filtered off.

• Korean Journal of Microbiology
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• v.14 no.4
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• pp.176-185
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• 1976

An improved procedure for the rapid purification of glucose-6-phosphate dehydrogenase from extracts of Saccharomyces cerevisiae was developed by using affinity chromatography. Among six affinty media tested, NADP$^{+}$-agarose and Affi-gel Blue were more effective than others (i.e., Affi-gel Red, AMP-agarose, ATP-agarose, and NAD$^{+}$-agarose). Conditions to desorb the enzyme bound to the affinity media were examined to increase the purity as well as yield. The best result was obtained when the column was developed with a linear gradient of KCl (0-1.0M). In case of Affi-gel Blue, introduction of NAD$^{+}$ (15mM) washing step prior to the salt gradient was most effective to remove NAD$^{+}$-binding proteins. For a large scale preparation of G-6-P dehydrogenase higher recovery was obtained by Affi-gel Blue than NADP$^{+}$-agarose, however, the purity of the enzyme was decreased by 10 times if the former was used as the affinity medium. The capacity of Affi-gel Blue for G-6-P dehydrogenase was found to be 5 times higher than that of NADP$^{+}$-agarose. Furthermore Affi-gel Blue could be reused repeatedly and its preparation is relatively easier and less expensive than NADP$^{+}$-agarose.X> +/-agarose.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.19-27
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• 2010

Submerged plants whose most of vegetative mass are below the water surface can have great effects on wetland biogeochemistry and water purification through their photosynthesis and nutrient uptake processes. In this study, change of dissolved oxygen concentration and pH as well as nutrient removal capacity of the submerged plant dominant wetland were investigated using wetland mesocosm experiments. Obvious periodic DO and pH fluctuation was observed due to photosynthetic activities of the submerged plants. It implies that the submerged plants can provide periodic or sequential changes of oxic and anoxic conditions that affect nitrification and denitrification processes and contribute permanent nitrogen removal in the wetland system. The pH changes in the wetland mesocosm suggested that submerged plant could also play an important role as a temporary $CO_2$ storage. Higher nutrient removal efficiency was observed in the submerged plant dominant wetland mesocosm. The removal efficiencies under experimental conditions were 38.89, 84.70, 91.21, 70.76, 75.30% of TN, DIN, $NH_4-N$, TP, $PO_4-P$ in the wetland mesocosm, while those were 26.11, 57.34, 63.87, 28.19, 55.15% in the control treatment, respectively.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.685-693
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• 1988

From leaching of Korean native halloysite with hot sulfuric acid, active species of siliceous aluminosilicate are obtained as residue, which gives the mole ratio of SiO2/Al2O3 10 and substantially removes most acid-soluble impurities. By dissolving the residue in sodium hydroxide at an ambient temperature sodium silicate solution is prepared, this is used for zeolite synthesis as one of starting materials. In order to prepare zeolite Type 4A thereform, addition of a proper aluminum source is made so that the composition of the reactant materials may be of the following mole ratios : Na2O/SiO2=1.2-1.5, SiO2/Al2O3=1.8-2.0 and H2O/Na2O=34-45 By careful control of ageing time and temperature, subsequent crystal growth is induced into microfine zeolite 4A, which gives optimum particle size distributjion being suitable for detergent builder. The zeolite products thus obtained and highly competitive with those from the use of the refined clay in comparison of their calcium exchange capacity, whiteness and particle size distribution. The present method shows a marginal advantage over the existing procedures requiring neitherseparate purification nor calcinating otherwise necessary for the raw clay ores in use.

• KSBB Journal
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• v.31 no.1
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• pp.79-84
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• 2016

Biofuel has been considered as promising renewable energy to solve various problems that result from increasing usage of fossil fuels since the early 20th century. In terms of chemical and physical properties as fuel, biobutanol has more merits than bioethanol. It could replace gasoline for transportation and industrial demand is increasing significantly. Production of butanol can be achieved by chemical synthesis or by microbial fermentation. The water hyacinth, an aquatic macrophyte, originated from tropical South America but is currently distributed all over the world. Water hyacinth has excellent water purification capacity and it can be utilized as animal feed, organic fertilizer, and biomass feedstock. However, it can cause problems in the rivers and lakes due to its rapid growth and dense mats formation. In this study, the potential of water hyacinth was evaluated as a lignocellulosic biomass feedstock in biobutanol fermentation by using Clostridium beijerinckii. Water hyacinth was converted to water hyacinth hydrolysate medium through pretreatment and saccharification. It was found that productivity of water hyacinth hydrolysate medium on biobutanol production was comparable to general medium.

• Journal of the Korean Institute of Landscape Architecture
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• v.23 no.3
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• pp.132-143
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• 1995

Comprehensive development projects were carried out on the Han River from 1982 to 1986 for the purpose of creating a more serviceable places such as a riverside parks and autoroads and so on. However because of the river development, river ecosystem and function were destroyed. And many local autonomous entity follows comprehensive development projects as if it is a model case. To investigate the impact that the river development effects the river ecosystem, two sites which are Anyangcheon and Sooipcheon were surveyed in the right of around plants ecosystem and structure. Two sites are creek of the Hna River. Sooipcheon maintains the sound ecosystem. It has sufficient carrying capacity for the river recreation activity. The reason is that a hydrophyte absorbs nutrients from the stream and the river ecosystem meets the around terrestrial one neturally. Number of hydrophyte increase from upstream going forward to downstream. Number of hydrophyte increase from upstream going forward to downstream. Anyangchoen is seriously polluted stream out of many branch stream of the Han river. In the upstream various woody plants and hydrophyte appeared. But from the river developed area at midstream, naturalized plants dominated such as Bidens tripartita, panicum dichotomiflorum etc. To manage the creek ecologically, hydrophyts were introduced in partly for natural purification after rehavilitate the riverside, and steadily monitoring is demanded.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.5
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• pp.603-610
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• 2013

According to industrialization, increased toxic chemicals discharge has been causing water pollution. Especially domestic sewage is a major source of water pollution. Sixty percent of the total wastewater discharged is domestic sewage. Self-purification capacity of rivers and streams is drastically reduced by the emission of domestic sewage, industrial wastewater and livestock wastewater. Although domestic sewage is managed by implementing standards and regulations, toxicity effect of domestic sewage to humans and the environment is not yet clearly understood. In this study, by using daphnia magna, the ecotoxicity of domestic swage was assessed. Cl, Cu, Pb, COD, T-N, DO, pH and residual chlorine were investigated as background concentrations. The experiments were conducted with water samples obtained from three local sewage treatment plants. The experiment results indicated that higher level of toxicity corresponds to the higher pollution concentrations. The higher level of combinations of background concentrations such as heavy metals leads to the worse ecotoxicity. Especially, the Cu concentration affects the TU value.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.651-651
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• 2015

The Because reduction facilities of existing non-point pollution source weren't balanced with each element technologies, most of case were what damaged scene nature of river, neutralized pollution sources and reduction effect. Therefore it's necessary to find a solution by integrating the operation system. Based on the comparative analysis that we have ran, we examined the capacity at individual operation's water purification and linked the treatment to detention pond, wetland and revetment.