• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.15-28
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• 2019

In accordance with the decommissioning plan for the Kori Unit 1 NPP, the reactor coolant system will be chemically decontaminated as soon as possible after permanent shutdown. This study developed the chemical decontamination process though the development project of decontamination technology of reactor coolant system and dismantled equipment for NPP decommissioning, which has been carried out since 2014. In this study, Oxidation/reduction process was conducted using system decontamination process development equipment of lab scale and was divided into unit and continuous processes. The optimal process time was derived from the unit process, and decontamination agent and the number of process were derived through the continuous processes. Through the unit process, the oxidation process took 5 hours and the reduction process took 4 hours. As optimum decontamination agent, the oxidizing agent was $200mg{\cdot}L^{-1}$ Permanganic acid + $200mg{\cdot}L^{-1}$ Nitric acid and the reducing agent was $2000mg{\cdot}L^{-1}$ Oxalic acid. In the case of the number of processes, all oxide films were removed during the two-cycle chemical decontamination process of STS304 and SA508. In the case of Alloy600, all oxide films were removed when chemical decontamination was performed for three cycles or more.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.53-60
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• 1997

A series of batch and lab-scale pilot tests were conducted to optimize the design parameters for the application of soil washing techniques to the soil contaminated by heavy metals. Cu, Pb, and Zn were selected as target heavy metals. The concentrations of Cu, Pb, and Zn were 500mg/kg dry soil, 1, 000mg/kg dry soil, and 500mg/kg dry soil, respectively. Citric acid and oxalic acid were used for the extractants. In the batch tests, the extraction efficiencies for Cu, Pb, and Zn were 79%, 72%, 72%, respectively. The proper extractant concentration and dilution ratio(weight/volume) for Cu and Pb were turned to be citric acid 50mM and 1:5, respectively. The extraction efficiencies were enhanced with the addition of 1~2% OA-5 or SDS. From pilot scale tests for Pb, first stage and second stage of soil washing resulted in the extraction efficiency of 59% and 78%, respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.189-195
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• 1997

A phosphate solubilizing bacterium (PSB) possessing a high ability to solubilize hydroxyapatite (HA) was isolated from the rhizosphere of wheat. The PSB markedly developed clear zones after inoculating for 36 hours at $30^{\circ}C$. This bacterium was identified as Enterobacter agglomerans through API 20E system and Biolog$^{TM}$ analysis. The values of similarity and distance coefficient from authentication trial of the strain were 0.656 and 4.79 respectively. High performance liquid chromatography (HPLC) of the products of this strain indicated that this strain excretes maily oxalic acid with som other organic acids. During the incubation period of E. agglomerans, the pH values showed an inverse correlation ($r^2=0.933^{**}$) with solubilization of inorganic phosphate. Acid phosphatase activity of the strain was 10-15 times greater than alkaline phosphatase activity. Alkaline phosphatase activity had almost constant near zero activity across time. The population of E. agglomerans greatly increased during the first day of inoculation ; however, it drastically decreased thereafter.

• The Korean Journal of Mycology
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• v.38 no.1
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• pp.54-56
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• 2010

This study was performed to develop anti-obesity Phellineus linteus powder for application as food additives. P. linteus powders which contained anti-obesity lipase inhibitor were prepared by freeze drying and spray drying. Effects of various additives on the quality of their powders were investigated. 10% over addition of dextrin and gum-arabia was good in the rheological properties of their powders and optimal spray temperature was near $130^{\circ}C$. When their powders were sealed and storaged at room temperature for 6 months, its characteristics were not changed. Especially, changes of its colors was repressed by addition of 0.3 M oxalic acid, citric acid and ascorbic acid than those by non-treatment.

• Microbiology and Biotechnology Letters
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• v.27 no.3
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• pp.246-251
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• 1999

To extend the storage period and to inhibit contamination of Kimchi by Escherichia coli, conditions of Kimchi brining and effects of the fermentation starter, halophilic Lactobacillus HL-48 were investigated. Optimum brining condition for Kimchi was accomplished in 15% NaCl and at pH2.5-3.0 adjusted by lactic acid. Starter-treated Kimchi showed pH 4.2 after 18hr fermentation, while the pH of starter-untreated Kimchi resulted in 3.3. After 36hr fermentation, the number of E. coli in starter-treated Kimchi was found clearly to decrease and not detected macroscopically, but contamination of E. coli (5.3$\times$103CFU/ml) was observed in starter-untreated sample. Organic acids in Kimchi contained organic acids such as oxalic acid, citric acid, malic acid and lactic acid. among ther, lactic acid content was remarkably high in the early fermentation stages. However, from 24hr fermentation, lactic acid content of starter-untreated Kimchi was higher than that of starter-treated Kimchi.

• Journal of Food Hygiene and Safety
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• v.8 no.3
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• pp.147-150
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• 1993

A novel rapid and sensitive method to detennine residual oxolinic acid in Acetes japonicus was developed. The residual oxolinic acid was extracted with ethylacetate and diluted oxalic acid, and interfering substances were removed by hexane. Fifty ppb residual concentration in the extract could be quantitated by UV-HPLC and the recovery rates were 79-91% according to the fortified amounts.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.102-108
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• 1998

This study was performed to establish manufacturing of garlic vinegar which has medical action component of garlic and functionality of vinegar. Optimum alcohol concentration, and garlic juice concentration for the mpnufacturing of garlic vinegar were 5%, 10%, respectively, and the optimum conditions were obtained when the fermentation was carried out at agitation of agitation of 120rpm and temperature of 3$0^{\circ}C$. The acetic acid content of optimum condition was 4.87% and thiosulfinate content was 37.5mg after 20days fermentation. The major organic acid compositions in garlic vinegar were oxalic acid, citric acid, malic acid and acetic acid, and free amino acid compositions were aspartic acid, threonine, serine, glutamic acid, alanine etc.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.2
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• pp.39-44
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• 1994

To prepare the basic information for the fermentation of high quality persimmon vinegar in the farm. the quality of the complex fermented persimmon vinegar(CFPV) was compared to that of naturally fermented persimmon vinegar (NFPV). The titratable acidity of the CFPV was 3% which was the half concentration of the NFPV. The content of total free sugar by HPLC was 6% in CFPV and NFPV was 5%. Organic acid compositions in persimmon vinegar were oxalic acid, malic acid, lactic acid, citric acid, succinic acid and glutaric acid in addition to acetic acid. Total content of the organic acids in NFPV was higer than in CFPV. Especially, the content of latic acid in NFPV was very higher than that of CFPV. the flavour, color and taste of persimmon fruit itself in CFPV were stronger than those in NFPV.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2006.10a
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• pp.87-87
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• 2006

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.416-417
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• 2019