• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4571-4584
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• 2022

The analysis of rapid flow transients in Reactor Coolant Pumps (RCP) is essential for a reactor safety study. An accurate and precise analysis of the RCP coastdown is necessary for the reactor design. The coastdown of RCP affects the coolant temperature and the colloidal crud in the primary coolant. A realistic and kinetic model has been used to investigate the behavior of activated colloidal crud in the primary coolant and steam generator that solves the pump speed analytically. The analytic solution of the non-dimensional flow rate has been determined by the energy ratio β. The kinetic energy of the coolant fluid and the kinetic energy stored in the rotating parts of a pump are two essential parameters in the form of β. Under normal operation, the pump's speed and moment of inertia are constant. However, in a coastdown situation, kinetic damping in the interval has been implemented. A dynamic model ACCP-SMART has been developed for System Integrated Modular and Advanced Reactor (SMART) to investigate the corrosion due to activated colloidal crud. The Fickian diffusion model has been implemented as the reference corrosion model for the constituent component of the primary loop of the SMART reactor. The activated colloidal crud activity in the primary coolant and steam generator of the SMART reactor has been studied for different equilibrium corrosion rates, linear increase in corrosion rate, and dynamic RCP coastdown situation energy ratio b. The coolant specific activity of SMART reactor equilibrium corrosion (4.0 mg s^-1) has been found 9.63×10^-3 µCi cm^-3, 3.53×10^-3 µC cm^-3, 2.39×10^-2 µC cm^-3, 8.10×10^-3 µC cm^-3, 6.77× 10^-3 µC cm^-3, 4.95×10^-4 µC cm^-3, 1.19×10^-3 µC cm^-3, and 7.87×10^-4 µC cm^-3 for ²⁴Na, ⁵⁴Mn, ⁵⁶Mn, ⁵⁹Fe, ⁵⁸Co, ⁶⁰Co, ⁹⁹Mo, and ⁵¹Cr which are 14.95%, 5.48%, 37.08%, 12.57%, 10.51%, 0.77%, 18.50%, and 0.12% respectively. For linear and exponential coastdown with a constant corrosion rate, the total coolant and steam generator activity approaches a higher saturation value than the normal values. The coolant and steam generator activity changes considerably with kinetic corrosion rate, equilibrium corrosion, growth of corrosion rate (ΔC/Δt), and RCP coastdown situations. The effect of the RCP coastdown on the specific activity of the steam generators is smeared by linearly rising corrosion rates, equilibrium corrosion, and rapid coasting down of the RCP. However, the time taken to reach the saturation activity is also influenced by the slope of corrosion rate, coastdown situation, equilibrium corrosion rate, and energy ratio β.

• KSBB Journal
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• v.24 no.1
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• pp.30-40
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• 2009

Statistical optimization of the production medium was carried out in order to find an optimal medium composition in itaconic acid fermentation process. Itaconic acid utilized in the manufacture of various synthetic resins is a dicarboxylic acid biosynthesized by fungal cells of Aspergillus terreus in a branch of the TCA cycle via decarboxylation of cis-aconitate. Through OFAT (one factor at a time) experiments, six components (glucose, fructose, sucrose, soluble starch, soybean meal and cottonseed flour) were found to have significant effects on itaconic production among various carbon- and nitrogen-sources. Hence, using these six factors, interactive effects were investigated via fractional factorial design, showing that the initial concentrations of sucrose and cottonseed flour should be high for enhanced production of itaconic acid. Furthermore, through full factorial design (FFD) experiments, negative effects of $KH_2PO_4$ and $MgSO_4$ on itaconic acid biosynthesis were demonstrated, when excess amounts of the each component were initially added. Based on the FFD analysis, further statistical experiments were conducted along the steepest ascent path, followed by response surface method (RSM) in order to obtain optimal concentrations of the constituent nutrients. As a result, optimized concentrations of sucrose and cottonseed flour were found to be 90.4g/L and 53.8g/L respectively, with the corresponding production level of itaconic acid to be 4.36 g/L (about 7 fold higher productivity as compared to the previous production medium). From these experimental results, it was assumed that optimum ratio of the constituent carbon (sucrose) and nitrogen (cottonseed flour) sources was one of the most important factors for the enhanced production of itaconic acid.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.44 no.4
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• pp.407-417
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• 2018

In this study, the antioxidant, cytoprotective and antimicrobial activities of 50% ethanol extract of Polygoni multiflori Radix (PMR) and its ethyl acetate fraction were evaluated to confirm the applicability as a functional ingredient. The activities of the major constituent of PMR were verified and 2, 3, 5, 4′-tetrahydroxystilbene 2-O-${\beta}$-D-glucoside (THSG) was confirmed to be the main component of extract and fraction using HPLC-DAD, LC-EIS-MS analysis. The phenolic and THSG contents of the ethyl acetate fraction were 11.1- and 3.0-folds higher than those of the ethanol extract, respectively. As a result of the DPPH assay and that of luminol dependent chemiluminescence assay in $Fe^{3+}$-EDTA/H2O2 system. the ethylacetate fraction was superior to the ethanol extract in free radical and ROS scavenging activities. Especially, the ethyl acetate fraction and THSG exhibited the similar scavenging activity like L-ascorbic acid in ROS scavenging activity. The ethyl acetate fraction perceived the most potent cytoprotective effect against oxidative damage of erythrocytes induced by photosensitization reaction, followed by the ethanol fraction, THSG and that of (+)-${\alpha}$-tocopherol, which was used as a positive control. Antimicrobial activities were evaluated by disc diffusion and broth microdilution assay against S. aureus, E. coli, P. aeruginosa and C. albicans. In particular, the antibacterial activity of the extract and fraction against S. aureus was superior to that of methyl paraben. Taken together, our results suggest that PMR could be used as a natural ingredient for antioxidant, cytoprotective and antimicrobial activities.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.1
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• pp.15-26
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• 2009

The purpose of this report was to provide the information about activity and safety of Yukmijihwang-tang by analyzing domestic/international papers and theses about Yukmijihwang-tang. Domestic/international papers and theses related to Yukmijihwang-tang were reviewed and analyzed. These papers were then classified by year, experimental method, and activity subject. The following results were obtained in this study. The study of Yukmijihwang-tang started from 1978 and was rapidly increased after 1990s. The study of Yukmijihwang-tang was continuously increased now and was mainly forcused on experimental model rather than clinical study. The paper of SCI journal or non-SCI journal was 27 volume and the other domestic paper was 64 volume. The total papers of Yukmijihwang-tang, 91 volume was analysed in this study. Allatoin, gallic acid, loganin, morroniside, paeoniflorin, paenol, urosolic acid were determined in Yukmijihwang-tang by using HPLC and HPLC-MS-MS. In classified Yukmijihwang-tang paper by experimental method and animal, more than a half study was in vivo experiment used rat. Furthermore clinical experiments were performed variously. As these studies were classified by subject, papers related to renal function were most abundant by 16 papers. Besides there were several papers related to cognitive vitality, anti-diabetic effect, immuno-regulation, reproductive activity, anti-oxidant effect, liver function, anti-cancer and blood pressure depress. According to basic research and clinic research data, it is supported that Yukmijihwang-tang was useful prescription in renal function, cognitive vitality, anti-diabetic effect and reproductive activity. Many study of basic and clinic research were performed and reported variously on Yukmijihwang-tang in domestic/international journal. According to basic research and clinic research data, it is supported that Yukmijihwang-tang was useful prescription in renal function, cognitive vitality, anti-diabetic effect and reproductive activity. However, studies on efficacy and mechanism of Yukmijihwang-tang should be conducted at the molecular biology level and studies on safety of Yukmijihwang-tang need to be completed at the clinical level.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.1
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• pp.115-130
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• 2013

The sectional methods of current design codes have been broadly used for the design of various kinds of reinforced concrete pile caps. Lately, the strut-tie model approach of current design codes also became one of the attracting methods for pile caps. However, since the sectional methods and the strut-tie model approach of current design codes have been established by considering the behaviors of structural concrete without D-regions and two-dimensional concrete structures with D-regions, respectively, it is inappropriate to apply the methods to the pile caps dominated by 3-dimensional structural behavior with disturbed stress regions. In this study, the refined 3-dimensional strut-tie models, which consider the strength characteristics of 3-dimensional concrete struts and nodal zones and the load-carrying capacity of concrete ties in tension regions, are proposed for the rational analysis and design of pile caps. To examine the validity of the proposed models and to verify the necessity of appropriate constituent elements for describing 3-dimensional structural behavior and load-transfer mechanism of pile caps, the ultimate strength of 78 reinforced concrete pile caps tested to failure was examined by the proposed models along with the sectional and strut-tie model methods of current design codes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.7 no.1
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• pp.11-22
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• 1987

A plane buoyant jet discharged vertically upward into a crossflow is analyzed by numerical solution of the governing equations of continuity, momentum and constituent transport. The turbulent transport is modelled by the Prandtl's mixing length theory. In the numerical solution procedure, the governing equations are transformed by stream function and vorticity transport, non-dimensionalyzed by discharge velocity, slot width, and parameters representing flow characteristics, and solved by Gauss-Seidel iteration method with successive underrelaxation. The numerical experiments were performed for the region of established flow of buoyant jet in the range of discharge densimetric Froude number of 4 to 32 and in the range of velocity ratio of 8 to 15, which is the ratio of discharge velocity to crossflow velocity. Variations of velocities and temperatures, flow patterns and vorticity patterns of receiving water due to buoyant jet were investigated. Also investigated are the effects of velocity ratio and discharge densimetric Froude number on the trajectories of buoyant jet. Computed are velocities, temperatures and local densimetric Froude numbers along the trajectory of the buoyant jet. Spreading rate and dispersion ratio were analyzed in terms of discharge densimetric Froude number, local densimetric Froude number and distance from the source along the jet trajectory. It was noted that the similarity law holds in both the profiles of velocity and temperatures across the jet trajectory and the integral type analysis of Gaussian distribution is applicable.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.12
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• pp.1981-1989
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• 2008

Different people buy the same or similar products for different reasons. Benefit segmentation attempts to understand these differences by grouping together people who assign a similar level of importance to the same attributes. We focused on identifying market segments for knit fabrics by comparing the relative attribute preference for knit fabrics according to segmented clusters, and testing to establish if there were significant differences between the preferences of clusters. Three consumer segments emerged, and there were three clusters with different ideal knit profiles: a preferred wool group, a preferred acrylic group, and a preferred long stitch length group. The preferred wool group and the preferred acrylic group rated the mixture ratio as the main attribute that determined their preference, followed by the stitch length. The preferred long stitch length group considered stitch length as being the most important attribute, followed by the mixture ratio. The difference in the preferences for the mixture ratio and stitch length of knit fabrics was the highest between the three clusters, The preferred wool group preferred a knit fabric that has a greater wool mixture ratio and a short stitch length, and the preferred acrylic group and long stitch length group preferred a knit fabric that had a higher acrylic mixture ratio and a short stitch length.

• Herbal Formula Science
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• v.21 no.2
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• pp.144-157
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• 2013

Objectives : The aim of this study was to evaluate the efficacy of Hwangnyeonhaedok-tang (HH) and Geongangbuja-tang (GB) on the plasma hormone level in mice exposed to cold stress. HH and GB are the representative prescriptions of cold and hot property, respectively. Methods : We established cold condition by confining ICR mice to a $4^{\circ}C$ cage for 24 hours, ICR mice were given a HH (100, 300, 1000 mg/kg) or GB (100, 300, 1000 mg/kg) extract orally twice a day for three consecutive days. From the second day, they were given cold stress ($4^{\circ}C$) for twenty four hours. To measure the plasma corticosterone, insulin, thyroxine, epinephrine and norepinephrine levels of mice, their blood samples were collected from cardiac puncture, immediately centrifuged at $4^{\circ}C$. The protein level of HSP70 and JNK was examined using western blot analysis in cortex and hypothalamus. Results : Oral administration of GB more significantly reduced plasma corticosterone level raised by cold stress than HH. Gardeniae Fructus (CJ), the constituent of HH, significantly increased the thyroxine level. Western blot analysis showed that cold stress-induced Heat shock protein 70 (HSP70) expression was increased by HH and GB, HH decreased JNK expression and GB increased JNK expression dose-depently in hypothalamus. Scutellariae Radix (HG), Zingiberis Rhizoma (GG) and Aconiti Tuber (BJ) decreased HSP70 in hypothalamus and GG, BJ decreased HSP70 in cortex as well. Conclusions : These results suggest Geongangbuja-tang (GB) is more effective for ameliorating the stress response caused by cold stress.

• Journal of Conservation Science
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• v.36 no.3
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• pp.178-186
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• 2020

Verdigris is a traditional artificial pigment reported on old research papers and according to the methods mentioned in the literature, it is manufactured by the corrosion of copper or copper alloys using vinegar and by further scraping the generated rust. Since the Three Kingdoms Period, various household products with copper alloys, such as bronze and brass, have been used, and pigment analysis of these cultural heritage items has revealed the presence of tin, zinc, lead, and copper in green pigments. Based on these data, five types of verdigris were prepared from copper and copper alloys, and analyzed. the analysis results revealed a bluish green pigmentation, and the chromaticity, particle shape, and oil absorption quantity of each verdigris differed based on the type of copper alloy used in its preparation. The main components of verdigris are Cu, Sn, Zn and Pb, and their proportions depended on the type of copper alloy used during manufacturing. However, the main constituent mineral of the pigments is the same as 'hoganite[Cu(CH₃COO)₂·H₂O]', regardless of the copper alloy used. The result of accelerated weathering test for stability evaluation revealed that verdigris was discolored rapidly, thereby indicating that its stability was low, in particular, the pigments comprising lead presented relatively lower stability.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.1
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• pp.17-23
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• 2008

In this study, plasma processing of metal surface is experimentally investigated to enhance the surface decontamination efficiency and to find out the reaction mechanism. Cobalt, the major contaminant in the nuclear facilities, and three fluorine-containing gases, $CF_4/O_2$, $SF_6/O_2$, and $NF_3$ are chosen for the investigation. Thin metallic disk specimens are prepared and their surface etching reactions with the three plasma gases are examined. Results show that the maximum etching rate of $17.2\;{\mu}m/min.$ is obtained with NF3 gas at $420^{\circ}C$, while with $CF_4/O_2$, $SF_6/O_2$ gas plasmas those of $2.56\;{\mu}m/min.$ and $1.14\;{\mu}m/min.$ are obtained, respectively. Along with etching experiments, constituent elements of the reaction products are identified to be cobalt, oxygen, and fluorine by AES (Auger Electron Spectroscopy) analysis. It turns out that the oxygen atoms are physically adsorbed ones to the surface from the ambient not participation ones during the analysis after reaction, which supports that the surface reaction of cobalt is mainly to be a fluorination reaction.