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Recovery of Strontium From Salt Solution After Chlorination
Sang Woon Kwon,Sang-Kwon Lee,Eun-Young Choi,Chang Hwa Lee 한국방사성폐기물학회 2022 한국방사성폐기물학회 학술논문요약집 Vol.20 No.1
Strontium-90 is a high heat-generating nuclide in spent nuclear fuel. The removal of the nuclide separation is indispensable to reduce the burden of storage and disposal of high-level radioactive waste. Korea Atomic Energy Research Institute has developed the molten salt immersion technique to separate the strontium by the chlorination of the strontium oxide in molten salt. It is needed to separate the salt for the recovery of strontium from the salt solution after the chlorination reaction. In this study, it was investigated on the recovery of the strontium from the salt. Vacuum distillation was used for the separation of strontium from the molten salt. The vapor pressures of the candidate salts were calculated by HSC chemistry and the apparent evaporation rates (AER) were measured at 830°C to evaluate the salts for strontium recovery. The candidate salts were LiCl, KCl, MgCl2, NaCl and CaCl2. The AERs of MgCl2 and NaCl were 1.9 and 1.3 g/cm2-h, respectively. Those two salts can be separated from the strontium compound even though the AER values are much lower than those of LiCl-KCl (~ 8 g/cm2-h). CaCl2 salt was rarely evaporated (AER < 0.03 g/cm2-h) and it is not suitable to use as a strontium recovery salt. Therefore, MgCl2, NaCl, LiCl and KCl can be regarded as candidates for a strontium recovery salt.
Kwon Jae-Woo,Kim Mi-Ae,Sim Da Woon,Lee Hwa Young,Rhee Chin Kook,Yang Min-Suk,심지수,김민혜,Kim So Ri,Park Chan Sun,Kim Byung-Keun,Kang Sung-Yoon,Choi Gil-Soon,Lee Hyun,Jang An-Soo,김상헌 대한천식알레르기학회 2022 Allergy, Asthma & Immunology Research Vol.14 No.3
Purpose: Oral corticosteroids (OCSs) are frequently prescribed for asthma management despite their adverse effects. An understanding of the pattern of OCS treatment is required to optimize asthma treatment and reduce OCS usage. This study evaluated the prescription patterns of OCSs in patients with asthma. Methods: This is a retrospective multicenter observational study. We enrolled adult (≥18 years) patients with asthma who had been followed up by asthma specialists in 13 university hospitals for ≥3 years. Lung function tests, the number of asthma exacerbations, and prescription data, including the days of supply and OCS dosage, were collected. The clinical characteristics of OCS-dependent and exacerbation-prone asthmatic patients were evaluated. Results: Of the 2,386 enrolled patients with asthma, 27.7% (n = 660) were OCS users (the median daily dose of OCS was 20 mg/day prednisolone equivalent to a median of 14 days/year). OCS users were more likely to be female, to be treated at higher asthma treatment steps, and to show poorer lung function and more frequent exacerbations in the previous year than non-OCS users. A total of 88.0% of OCS users were treated with OCS burst with a mean dose of 21.6 ± 10.2 mg per day prednisolone equivalent to 7.8 ± 3.2 days per event and 2.4 times per year. There were 2.1% (51/2,386) of patients with OCS-dependent asthma and 9.5% (227/2,386) with exacerbation-prone asthma. These asthma phenotypes were consistent over the 3 consecutive years in 47.1% of OCS-dependent asthmatic patients and 34.4% of exacerbation-prone asthmatic patients when assessed annually over the 3-year study period. Conclusions: We used real-world data from university hospitals in Korea to describe the OCS prescription patterns and relievers in asthma. Novel strategies are required to reduce the burden of OCS use in patients with asthma.
Significance of Hemodynamic Effects on the Generation of Atherosclerosis
Sang-Ho Suh,Hyung-Woon Roh,Dong-Joo Kim,Hyuck-Moon Kwon,Byoung-Kwon Lee 대한기계학회 2005 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.19 No.3
Atherosclerosis, which is a degenerative vascular disease, is believed to occur in the blood vessels due to deposition of cholesterol or low density lipoprotein (LDL) Atherosclerotic lumen narrowing causes reduction of blood flow due to hemodynamic features Several hypothetical theories related to the hemodynamic effects have been reported. high shear stress theory, low shear stress theory, high shear stress gradient theory, flow separation and turbulence theory, and high pressure theory However, no one theory clearly explains the causes of atherosclerosis The objective of the present study was to investigate the mechanism of the generation of atherosclerosis in the study, the database of Korean carotid and coronary arteries for geometrical and hemodynamic clinical data was established The atherosclerotic Sites were predicted by the computer simulations. The results of the computer Simulation were compared with the in vivo experimental results, and then the pathogenesis of atherosclerosis by using the clinical data and several hypothetical theories were investigated From the investigation, it was concluded carefully that the mechanism of the generation of athelosclerosls was related to the hemodynamic effects such as flow separation and oscillatory wall shear stress on the vessel walls.
Conducting Polymer-Silica Composites for Immobilization of Enzymes
Kwon, Sang-Woon,Jeong, Bo-Ock,Lee, Eun-Hee,Kim, Yong-Shin,Jung, Yong-Ju Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.5
A new enzyme immobilization method based on hydrophobic interaction between supporting material and enzyme has been successfully developed. The efficacy of the new technique has been investigated by loading a horse radish peroxidase (HRP) enzyme on the surface of conducting polymer-silica composites and by measuring the enzyme activity and leaching property of HRP loaded within polymer-silica composites. The immobilized HRP enzyme showed activity profiles similar to that of free HRP in phosphate buffer (pH 6). Above all, HRP adsorbed on the polymer-silica composites has showed excellent stability over 10 days, compared to HRP adsorbed on the pristine silica. It is thought that with appropriate optimization works, the present method would be used as a cost-effective and facile route for the immobilization of biomolecules.
Microbiological survey of Korean animal facilities from 2014 to 2019
Sang woon Kim,Hi jo SHIN,Se hee PARK,Teak chang LEE,Hae jin LEE,Ok sung MOON,Ki hoan NAM,Won kee YOON,Hyoung chin KIM,Hyo jung KWON,Young Suk WON 한국실험동물학회 2021 한국실험동물학회 학술발표대회 논문집 Vol.2021 No.7
To survey the mouse microbiological contamination rate in Korean animal facilities, we tested for common contaminants in these facilities using serological, culture, and parasitological methods. A total of 21,292 experimentally housed mice from 206 animal facilities, including hospitals, universities, companies and research institutes, were tested over a 6-year period from 2014 to 2019. The most commonly found contaminants were various species of non-pathogenic protozoa (47.2%). The most common pathogenic bacteria were Staphylococcus aureus (21.2%), Pasteurella pneumotropica (12.5%) and Pseudomonas aeruginosa (5.8%). Mouse hepatitis virus (6.1%) was detected, but no other viral or bacterial pathogens were found. These results establish that the main pathogens that currently contaminate animal facilities in Korea are opportunistic pathogens, whereas important such as those in categories B or C, were decreased.
Two Step Process for the Recovery of Strontium From Salt Solution
Sang Woon Kwon,Eunsoo Lee,Byungsuk Park,Joon Bo Shim,Chang Hwa Lee 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1
It has been investigated on the management of the nuclides in KAERI. Strontium-90 is a high heatgenerating nuclide in spent nuclear fuel. It is needed to separate the salt from the salt solution for the recovery of strontium after the chlorination of the strontium oxide in molten salt. A vacuum distillation technology was used for the separation of strontium from the molten salt. It was investigated on operating conditions of reactive distillation process for the recovery of the strontium from the salt solution. At a reduced pressure, considerable amount of the carbonation agents such as K2CO3 and Li2CO3 were reduced during heating in the distiller due to the thermal decomposition. Therefore, the two step process was proposed, which is composed of a reaction step at an atmospheric pressure and a salt distillation step at a reduced pressure. In the reaction step, the condition of low temperature and high pressure is suitable to suppress the decomposition of the carbonation agent. In the salt distillation step, reduced pressure is preferable at a suitable temperature depending on the evaporation rate of the salt.
Sang Gon Kim,Seonghyu Shin,Gun-Ho Jung,Seong-Guk Kim,Chung-Guk Kim,Mi-Ok Woo,Min Ju Lee,Jin-Seok Lee,Beom-Young Son,Woon-Ho Yang,Young-up Kwon,Kang-Bo Shim 한국작물학회 2016 한국작물학회지 Vol.61 No.3
In monsoon climates, persistent shade is a troublesome weather condition with an impact on the growth and yield of corn (Zea mays L.). We imposed 7, 14, 21, and 28 days of consecutive shade (CS) on Gwangpyeongok and P3394 corn hybrids at the beginning of the kernel filling stages. Shade had little impact on leaf area and dry matter accumulation in the stem and leaves. However, dry matter accumulation in the ear was severely reduced by approximately 28% and 53% after 14 and 28 days of CS, respectively. For the components of grain yield, 7 and 14 days of shade did irreparable damage to the number of filled kernels, the kernel number per ear row, and the percent of filled kernels, but did little damage or reversible damage after removal of the shade to the 100-grain weight and the row number per ear. Shade significantly reduced the relative growth rate (RGR) due to a decrease in the net assimilation rate (NAR). These results suggest that source activity limitation by shade during the kernel filling stages leads to the inhibition of sink activity and size. The yield of biomass, ear, and grain logistically declined as the length of CS increased. Probit analysis revealed that the number of days of CS needed to cause 25% and 50% reductions in grain yield were 3.7 and 23.1, respectively. These results suggest that the plant yield loss induced by shade at the beginning of the kernel filling stages is mainly achieved within the first 7 days of consecutive shade.