• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1339-1346
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• 2024

Electrorefining in molten salts is used for purifying actinides. Optimizing electrorefining is key to minimizing processing time and radiological waste. One possible way of improving electrorefining efficiency is using an AC superimposed DC waveform. This waveform has demonstrated potential benefits in aqueous solutions but has never been utilized in a molten metal, molten salt application. This work investigates the effects of using an AC superimposed DC waveform on molten bismuth electrorefining in a molten LiCl-KCl-CaCl2 eutectic. Bismuth has been identified as a potential surrogate for plutonium electrorefining and a potential cathode in electrorefining used nuclear fuel (UNF). All electrorefining runs resulted in a high purity cathode ring and high yield with exception of the run using a low-frequency, high-amplitude superimposed AC waveform, which experienced some contamination and a lower yield. The other three AC superimposed DC runs experienced an average yield 6.7 % higher than the average yield of the DC runs. The electrorefining run using the high-frequency, high-amplitude superimposed AC signal had the highest yield. It is recommended in future studies to investigate the statistical variability of electrorefining yield and current efficiency and the impact of AC superimposed DC waveforms on solidified bismuth anodes.

• Journal of the Mineralogical Society of Korea
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• v.20 no.1 s.51
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• pp.1-6
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• 2007

Hectorite was synthesized by a two-step hydrothermal process from $Mg(OH)_{2}$, water glass (${\sim}30\;wt%\;SiO_{2}$) and Li-compound at $90{\pm}5^{\circ}C$. The product shows excellent dispersion and swelling properties. The mixture of the starting materials was heated in a glass vessel for the first reaction with continuous stirring and the pH of the solution was adjusted to $6{\sim}8$, resulting in the formation of a precursor of hectorite. The excess salt components were washed out from the resulting slurry and then was matured in the glass vessel for the 2nd reaction. Li compound was added during the reaction. After a 10 h retention, the gel of hectorite was formed. The XRD pattern of the synthesized one was coincided with that of natural hectorite and SEM study revealed uniform grains 50 m in diameter. The d001 basal spacing of the product moved from 12 to $17.4\;{\AA}$ after glycolation treatment. The measured value of CEC and the swelling capacity was 90 cmol/kg and $60{\sim}70\;mL/2\;g$, respectively.

• Journal of Life Science
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• v.34 no.7
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• pp.500-508
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• 2024

Recently, there has been increasing interest in enhancing the indoor air quality, particularly in response to the growing utilization of public facilities. The focus of this study was on assessing the efficacy and safety of an air sterilizer equipped with electrolytic salt catalysts. To that end, we evaluated the antimicrobial activity of the vapor spraying from the air sterilizer and its cytotoxicity in condensed form on human cell lines (HaCaT, BEAS-2B, and THP-1). Against the test organisms, which comprised five bacterial strains (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium) and one fungal strain (Candida albicans), the air sterilizer exhibited relatively high antimicrobial activities ranging from 10.89 to 73.98% following 1 and 3 hr of vapor spraying, which were notably time-dependent. Importantly, cytotoxicity assessments on human cells indicated no significant harmful effect even at a 1.0% concentration. Comprehensive safety evaluations included morphological observations, gene expression (Bcl-2, Bax) tests, and FACS analysis of intracellular ROS levels. Consistent with previous cytotoxicity findings, these estimates demonstrated no significant changes, highlighting the air sterilizer's safety and antimicrobial activities. In a simulated 20-hr operation within an indoor environment, the air sterilizer not only showed an 89.4% removal of total bacteria but also a 100.0% removal of Escherichia sp. and fungi. This research outlines the potential of the developed electrolytic salt catalyst air sterilizer to effectively remove indoor microbial pollutants without compromising human safety, underscoring the solution that it offers for improving indoor air quality.

• Food Science of Animal Resources
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• v.27 no.3
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• pp.363-370
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• 2007

In order to identify probiotic microorganisms, 25 isolates of Lactobacillus sp. were selected from kimchi based on their growth rates, lactic acid production and salt tolerance. The isolate JK-01 was identified as Lactobacillus plantarum by the API kit and 16S rDNA analysis (99.9% of homology), and named as L. plantarum JK-01. The maximum number of L. plantarum JK-01 was reached at 18 hr fermentation in MRS broth and the pH gradually decreased to 4.5. L. plantarum JK-01 showed high enzyme activities for xylanase, amylase, protease, and phytase on MRS agar plates containing each substrate. L. plantarum JK-01 showed high resistance to acidic pH and bile salts, and grew well even at pH 2.0 and 1.0% bile salt. In particular, L. plantarum JK-01 showed high heat stability as shown by $3.3{\times}10^3$ CFU/mL at $60^{\circ}C$. The isolate showed remarkable antimicrobial activity against E. coli in MRS broth based on its disappearance after 18 hr and clear zone formation using a paper disk assay. These results suggest that L. plantarum JK-01 may be probiotic in nature.

• Research in Community and Public Health Nursing
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• v.11 no.2
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• pp.358-372
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• 2000

The purpose of this study was to describe the way of life (such as smoking habits, alcohol consumption, exercise, duration of sleep, eating habits etc.), physical. psychological and overall health complaints and to identify the relationship between the way of life and health complaints of the nursing students. Data was collected with the self-administered OMI( Okayama Medical Index Health Questionnaire, devised Cornell Medical Index) from 766 nursing students and was analyzed. For data analysis, descriptive statistics and an ANOVA with an SPSS/PC+ program were used. The results were as follows: 1. The mean age of subjects was 21.0557(2.7618) years old in their 1st, 2nd, 3rd and 4th year-classes of nursing departments and college students in 4 regions of Korea. 62.1% of subjects were of the proper body weight, 2.0% were overweight, and 28.3% were underweight. Most subjects did not have a past history of disease, but 1.8% of subjects had experienced a blood transfusion. 2. 28.3% of the subjects had averaged 7 hours of sleep, 98.5% were nonsmokers, 91.2% were nondrinkers, 74.7% of subjects had milk intake sometimes, 53.7% of the subjects had an average salt intake, 49.6% of the subjects usually had a green vegetable intake, 45.4% of the subjects sometimes had fatty food intake, 64.8% of the subjects had good taste, 29.5% of the subjects enjoyed physical exercise. 3. The highest percentages of 'yes' among physical. psychological and overall health complaints were observed in the question 'Do you have gastric pain?'(60.2%), 'Are you confused of disorderly?' (37.2%), 'Physical body was burdensome and fatigued.'(57.3%). 4. The total O.M.I. score ranged from 1 to 89 with an average of 22.91(SD=12.10). A statistically significant difference was observed for the physical. psychological complaints for alcohol consumption. and for the psychological complaints for salt and fatty food intake. These conclusions should provide grounds for future studies of strategies for health promoting lifestyle for nursing students and their health concerns. Further research is required to investigate the life environmental and psychological factors affecting the way of life for nursing students and their health status, to analyze the health behavior of nursing students related with their culture and consciousness. Also epidemiologic research methodology, such as prospective cohort study should be considered to explore the performing process of nursing student's health behavior related with the occurrence of diseases.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.574-580
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• 2019

ATP drives the conformational change of the group II chaperonin from the open lid substrate-binding conformation to the closed lid conformation to encapsulate an unfolded protein in the central cavity. It is thought that the folding activity of group II chaperonin is strongly correlated with the ATP-dependent conformational change ability. In order to confirm the dependence of the reaction temperature and ATP concentration of PhCpn, the ATPase activities were measured under different reaction temperatures and ATP concentrations. The maximal ATPase activity of PhCpn was observed at 80℃ and 3 mM ATP concentration. As a result of ATPase activity according to the type of salt ions, the highest activity was observed at 300 mM LiCl among the univalent cations and 5 mM MgCl₂ among the divalent cations, respectively. The values of Km and Vmax for ATP substrate were estimated as 2.17 mM and 833.3 μM/min, respectively. This results provide the enzymatic information of PhCpn when the prolonged and high activities of pharmaceutical and industrial proteins (or enzymes), by using chaperonin molecules, are required.

• Analytical Science and Technology
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• v.23 no.1
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• pp.45-53
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• 2010

For the determination of chlorine in uranium compound, analytical methods by using a steam distillation and a pyrohydrolysis have been developed. The steam distillation apparatus was composed of steam generator, distilling flask and condenser etc. The samples were prepared with an aliquot of LiCl standard solution and a simulated spent nuclear fuel. A sample aliquot was mixed with a solution containing 0.2 M ferrous ammonium sulfate-0.5 M sulfamic acid 3 mL, phosphoric acid 6 mL and sulfuric acid 15 mL. The chloride was then distilled by steam at the temperature of $140^{\circ}C$ until a volume of $90{\pm}5\;mL$ is collected. The pyrohydrolysis equipment was composed of air introduction system, water supply, quartz reaction tube, combustion tube furnace, combustion boat and absorption vessel. The chloride was separated from powdered sample which is added with $U_3O_8$ accelerator, by pyrohydrolysis at the temperature of $950^{\circ}C$ for 1 hour in a quartz tube with a stream of air of 1 mL/min supplied from the water reservoir at $80^{\circ}C$. The chlorides collected in each absorption solution by two methods was diluted to 100 mL and measured with ion chromatography to determine the recovery yield. For the ion chromatographic determination of chlorine in molten salt retained in a metal ingot, the chlorine was separated by means of pyrohydrolysis after air and dry oxidation, and grinding for the sample.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.15 no.4
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• pp.321-332
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• 2017

In order to build a general model of a high-throughput uranium electrorefining process according to the electrode configuration, numerical analysis was conducted using the COMSOL Multiphysics V5.3 electrodeposition module with Ordinary Differential Equation (ODE) interfaces. The generated model was validated by comparing a current density-potential curve according to the distance between the anode and cathode and the electrode array, using a lab-scale (1kg U/day) multi-electrode electrorefiner made by the Korea Atomic Energy Research Institute (KAERI). The operating temperature was $500^{\circ}C$ and LiCl-KCl eutectic with 3.5wt% $UCl_3$ was used for molten salt. The efficiency of the uranium electrorefining apparatus was improved by lowering the cell potential as the distance between the electrodes decreased and the anode/cathode area ratio increased. This approach will be useful for constructing database for safety design of high throughput spent nuclear fuel electrorefiners.

• Journal of Korean Medical classics
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• v.22 no.3
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• pp.79-95
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• 2009

Background : Eye diseases refer to a wide range of disconveniences from conjunctivitis, pterygium, glaucoma to even blindness. Acupuncture has been widely used in Korea throughout the history and provides an efficient method in the treatment of them. Objectives : Establish a distinctive and efficient acupuncture method for the treatment of eye diseases based in literature research. Method : We reviewed four Korean medical literature, "Guide to Swollen Sore Treatment[治腫指南]", "Treasured Mirror of Eastern Medicine[東醫寶鑑]", "Experiential Prescriptions of Acupuncture and Moxibustion[鍼灸經驗方]", and "Essential Rhymes on Acupuncture and Moxibustion by Master Saam[舍岩鍼法]", and analyzed the therapeutic characteristics in the treatment of eye diseases. Result : 1. According to "Guide to Swollen Sore Treatment[治腫指南]", various methods were applied in the treatment of eye diseases. We can cite salt water washing method after needling, pricking bloodletting method using three-edged needle, surgery method using bent needle and lance needle, or sore treatment using sliced bean-curd and ground Aristolochiae Fructus among others. Acupuncture points like GV20[百會], BL1[睛明], EX-HN5[太陽], GB20[風池], GV24[神庭], GB1[瞳子髎], and GB15[臨泣] were mostly needled. 2. In "Treasured Mirror of Eastern Medicine[東醫寶鑑]", pricking bloodletting method were most frequently used in comparison to single acupuncture or moxibustion methods. Applied points were GV20[百會], BL1[睛明], LI4[合谷], EX-HN5[太陽], GB37[光明], BL18[肝兪], GB20[風池], BL2[攢竹], GB1[瞳子髎], and ST36[三里]. Also selections of adjacent points were considered important. 3. In respect to treatment methods "Experiential Prescriptions of Acupuncture and Moxibustion [鍼灸經驗方]" has some similarity to "Treasured Mirror of Eastern Medicine[東醫寶鑑]" as pricking bloodletting method were mostly used. Also focused on normal Qi flow through meridian. Points like BL18[肝兪], BL1[睛明], LU5[尺澤], EX-HN5[太陽], LI4[合谷] were used. 4. "Essential Rhymes on Acupuncture and Moxibustion by Master Saam[校勘舍岩道人鍼法]" considered visceral pattern identification method fundamental in the diagnosis and treatment of eye diseases. Specifically, Liver, Heart, Stomach, Lung, Kidney identification methods are presented. Combined both corresponding and connecting meridians supplementation and draining methods according to mother-child relation. Also Saam master's own experiential prescriptions are noted. Conclusions : After previous study on stroke, we could also find various efficient methods according to eye diseases, through literature research of korean medical classics. This study will concurrently result in establishing distinctive therapeutic method characteristic of Korea.

• Polymer(Korea)
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• v.29 no.4
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• pp.403-407
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• 2005

In this work, the solid polymer electrolyte (SPE) composites, which are composed of poly(ethylene oxide) (PEO), mesoporous mobil crystalline material-41 (MCM-41), and lithium salt, are prepared in order to investigate the influence of MCM-41 contents on the ionic conductivity of the composites. The crystallinity of the SPE composites was evaluated using differential scanning calorimeter (DSC) and X-ray diffraction (XRD). The ionic conductivity of the SPE composites was measured by the frequency response analyzer (FRA). As a result, the addition of MCM-41 into the polymeric mixture prohibited the growth of PEO crystalline domain due to the mesoporous structures of the MCM-41. The $P(EO)_{16}LiClO_4$/MCM-41 electrolytes show an increased ion conductivity as a function of MCM-41 content up to 8 $wt\%$ and a slightly decreased conductivity over 8 $wt\%$. These ion conductivity characteristics are dependent on a change of polymer crystallinity in the presence of MCM-41 system.