• Nuclear Engineering and Technology
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• v.53 no.3
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• pp.1029-1040
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• 2021

For the structural integrity evaluation of pressurized water reactor (PWR) steam generator (SG) tubes subjected to transient hydraulic loading, determination of the tube-to-tube gap velocity and static pressure distributions along the tubes is prerequisite. This paper addresses both computational fluid dynamics (CFD) and analytical approaches for predicting the tube-to-tube gap velocity and static pressure distributions during blowdown following a feedwater line break (FWLB) accident at a PWR SG. First of all, a comparative study on CFD calculations of the transient velocity and pressure distributions in the SG secondary sides for two different models having 30 or no tubes is performed. The result shows that the velocities of sub-cooled water flowing between any adjacent two tubes of a tubed SG model during blowdown can be roughly estimated by applying the specified SG secondary side porosity to those of the no-tubed SG model. Secondly, simplified analytical approximate solutions for the steady two-dimensional SG secondary flow velocity and pressure distributions under a given discharge flowrate are derived using a line sink model. The simplified analytical solutions are validated by comparing them to the CFD calculations.

• Journal of Electrochemical Science and Technology
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• v.10 no.3
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• pp.257-270
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• 2019

The inhibition performance of sodium gluconate (SG), cetyltrimethylammonium bromide (CTAB) and their mixture (SG/CTAB) on the corrosion behavior of ${\alpha}$-brass in 0.5 M $H_2SO_4$ solution has been investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS), Inductively Coupled Plasma Spectrometry (ICPS) and molecular dynamics (MD) simulation techniques. The results reveal that SG with 5ppm CTAB, noted SG/CTAB, acts as a good corrosion inhibitor and its inhibition efficiency reached 89% after 24 h immersion in sulfuric acid solution, but slightly decreased at higher temperatures. The polarization curves displayed that SG/CTAB acts as a cathodic-kind inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that the addition of 5ppm CTAB to different concentrations of SG considerably increases the corrosion resistance of ${\alpha}$-brass. The SEM-EDS and ICPS analyses support the experimental results. Further, molecular dynamics (MD) simulations were used to understand the adsorption profiles of SG/CTAB on Cu(111) and Zn(111) surfaces.

• Review of KIISC
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• v.28 no.4
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• pp.6-12
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• 2018

국제전기통신연합(ITU)은 UN 산하 정보통신기술에 대한 국제표준을 담당하고 있으며, 전기통신표준화부문(ITU-T), 전기통신개발부문(ITU-D), 그리고 전파통신 부문(ITU-R)으로 구성되어 있다. ITU-T는 역할과 임무에 따라 11개의 연구반 (SG, study group)으로 구성되어 있고, 정보통신 환경에서 사용되는 정보보호 국제표준은 ITU-T SG17(보안, 의장: 순천향대 염흥열 교수)에서 담당하고 있다. 본 논문에서는 2018년 3월 스위스 제네바에서 개최된 SG17 국제회의 주요 결과 및 향후 전망에 대해 분석하고자 한다.

• Review of KIISC
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• v.30 no.4
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• pp.7-16
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• 2020

국제전기통신연합(ITU)은 UN 산하 정보통신기술에 대한 국제표준을 담당하고 있으며, 전기통신표준화부문(ITU-T), 전기통신개발부문(ITU-D), 그리고 전파통신 부문(ITU-R)으로 구성되어 있다[1]. ITU-T 산하에는 역할과 임무에 따라 11개의 연구반(SG, Study Group)을 구성하고 있으며, SG17(보안, 의장: 순천향대 염흥열 교수)에서 정보보호 국제표준을 담당하고 있다[2]. 본 논문에서는 최근에 개최된 SG17 국제회의(2019년 8월, 2020년 3월/5월)의 주요 결과 및 향후 전망에 대해 분석하고자 한다.

• Information and Communications Magazine
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• v.12 no.3
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• pp.37-48
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• 1995

전기통신에 관한 국제 표준을 다루고 있는 ITU-T의 여러 Study Group들 중에서 ISDN에 관한 국제 표준의 제정으로 우리에게 더 많이 알려진 SG13의 연구분야는 '일반적인 망 관점(General Network Aspeats)'분야이다. 본 고에서는 금번 연구회기('93~'96)부터 적용된 ITU의 기구개편 및 Study Group 개편에 따라 기존의 SG XVlll에서 SG13으로 개편된 본 연구반의 주요한 표준화 동향을 지난 '94년 11월 제네바 회의 결과를 중심으로 이제까지의 주요 연구결과와 더불어 짚어보고자 한다.

• Review of KIISC
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• v.29 no.4
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• pp.5-11
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• 2019

국제전기통신연합(ITU)은 UN 산하 정보통신기술에 대한 국제표준을 담당하고 있으며, 전기통신표준화부문(ITU-T), 전기통신개발부문(ITU-D), 그리고 전파통신 부문(ITU-R)으로 구성되어 있다. ITU-T는 역할과 임무에 따라 11개의 연구반(SG, Study Group)으로 구성되어 있고, 정보보호 국제표준은 ITU-T SG17(보안, 의장: 순천향대 염흥열 교수)에서 담당하고 있다. 본 논문에서는 스위스 제네바에서 개최된 SG17 국제회의(2018년 8월, 2019년 1월) 주요 결과 및 향후 전망에 대해 분석하고자 한다.

• Review of KIISC
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• v.33 no.4
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• pp.75-81
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• 2023

본 논문에서는 국제전기통신연합(ITU)의 정보통신기술 표준을 담당하고 있는 ITU-T에서 보안 분야표준을 제정하고 있는 SG17에서의 양자암호 표준화 최신 동향을 살펴보았다. ITU-T SG17에서 양자암호 관련 표준화는 실무반인 Q15에서 담당하고 있다. 양자암호통신은 더 이상 쪼갤 수 없는 물리량의 최소 단위인 양자(Quantum)의 특성을 다양한 통신서비스에 적용하여 가장 높은 수준의 보안 서비스를 제공하는 것을 목적으로 하고 있고, 이를 위해 표준화가 필요한 영역에서의 보안 요구 사항과 그와 관련된 상호호환성을 보장하기 위한 다양한 영역의 표준화를 ITU-T SG17 Q15에서 진행 중에 있는데, 해당 실무반의 표준화 연혁과 현재 진행 중인 다양한 표준화 과제의 최신 표준화 현황을 살펴보았다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.7
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• pp.980-988
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• 2014

Seungmagalgeuntang (SG) is broadly used in traditional Oriental medicine especially in Korea, China, and Japan, for its many pharmacological effects. This study was carried out to investigate the antioxidative, antimicrobial, and anticytotoxic activities of SG and fermented seungmagalgeuntang (FSG). DPPH radical scavenging activities of SG and FSG were 70% and 74%, respectively, which increased slightly by fermentation. Nitrite scavenging activities were strongly altered at pH 1.2, (36.4% in SG and 38.3% in FSG) by addition of $200{\mu}g/g$. Superoxide dismutase-like activities were from 21.5% to 23.3% at a concentration of 0.4 mg/mL, and the highest value were observed in FSG. Total flavonoid contents of SG and FSG were 47.1 and $52.1{\mu}g/L$, respectively which shows an increase upon fermentation. In the antimicrobial activity test, $MIC_{50}$ values of SG and FSG were $800{\mu}g/mL$ for Candida albicans and 3,200 and $1,600{\mu}g/mL$ for Staphylococcus epidermidis and Staphylococcus aureus, respectively. Antibacterial effects were higher in FSG compared to SG. Anticytotoxic cadmium toxicities ranged from 63.5% to 76.1% at $10{\mu}g/mL$ of SG and FSG, and the highest value was observed in FSG. In the sensory evaluation, color, flavor, and overall preference values were higher in FSG.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.257-267
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• 2017

Background: Heat-processed ginseng, sun ginseng (SG), has been reported to have improved therapeutic properties compared with raw forms, such as increased antidiabetic, anti-inflammatory, and antihyperglycemic effects. The aim of this study was to investigate the antiobesity effects of SG through the suppression of cell differentiation and proliferation of mouse 3T3-L1 preadipocyte cells and the lipid accumulation in Caenorhabditis elegans. Methods: To investigate the effect of SG on adipocyte differentiation, levels of stained intracellular lipid droplets were quantified by measuring the oil red O signal in the lipid extracts of cells on differentiation Day 7. To study the effect of SG on fat accumulation in C. elegans, L4 stage worms were cultured on an Escherichia coli OP50 diet supplemented with $10{\mu}g/mL$ of SG, followed by Nile red staining. To determine the effect of SG on gene expression of lipid and glucose metabolism-regulation molecules, messenger RNA (mRNA) levels of genes were analyzed by real-time reverse transcription-polymerase chain reaction analysis. In addition, the phosphorylation of Akt was examined by Western blotting. Results: SG suppressed the differentiation of 3T3-L1 cells stimulated by a mixture of 3-isobutyl-1-methylxanthine, dexamethasone, and insulin (MDI), and inhibited the proliferation of adipocytes during differentiation. Treatment of C. elegans with SG showed reductions in lipid accumulation by Nile red staining, thus directly demonstrating an antiobesity effect for SG. Furthermore, SG treatment down-regulated mRNA and protein expression levels of peroxisome proliferator-activated receptor subtype ${\gamma}$ ($PPAR{\gamma}$) and CCAAT/enhancer-binding protein-alpha ($C/EBP{\alpha}$) and decreased the mRNA level of sterol regulatory element-binding protein 1c in MDI-treated adipocytes in a dose-dependent manner. In differentiated 3T3-L1 cells, mRNA expression levels of lipid metabolism-regulating factors, such as amplifying mouse fatty acid-binding protein 2, leptin, lipoprotein lipase, fatty acid transporter protein 1, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase, were increased, whereas that of the lipolytic enzyme carnitine palmitoyltransferase-1 was decreased. Our data demonstrate that SG inversely regulated the expression of these genes in differentiated adipocytes. SG induced increases in the mRNA expression of glycolytic enzymes such as glucokinase and pyruvate kinase, and a decrease in the mRNA level of the glycogenic enzyme phosphoenol pyruvate carboxylase. In addition, mRNA levels of the glucose transporters GLUT1, GLUT4, and insulin receptor substrate-1 were elevated by MDI stimulation, whereas SG dose-dependently inhibited the expression of these genes in differentiated adipocytes. SG also inhibited the phosphorylation of Akt (Ser473) at an early phase of MDI stimulation. Intracellular nitric oxide (NO) production and endothelial nitric oxide synthase mRNA levels were markedly decreased by MDI stimulation and recovered by SG treatment of adipocytes. Conclusion: Our results suggest that SG effectively inhibits adipocyte proliferation and differentiation through the downregulation of $PPAR{\gamma}$ and $C/EBP{\alpha}$, by suppressing Akt (Ser473) phosphorylation and enhancing NO production. These results provide strong evidence to support the development of SG for antiobesity treatment.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.27-32
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• 2001

Antibiotic resistance of thirty strains of Shigella sonnei isolatedfrom patient of Shigellosis outbreke at Young Cheon area in 1998 was tested. Twenty-seven strains were resistant to Tr(Trimethoprim-Sulfamethoxazol) and Shigella sonnei SG-48 was resistant to Tr(Trimethopirm-Sulfamethoxazol), Ap(Ampicillin), Cp(Cephalothin) and Pi(Piperacillin). Shigella sonnei SG-49, SG-66, and SG-73 were senstive to all tested antibiotics. Physiological charactristics of isolated Shigella sonnei SG-48, SG-49, SG-57, and SG-73 such as effect of pH, NaCl concentration and temperature on the growth, survival in adverse condition and heat resistance were investigated Growth of the strains were inhibited at pH 4 and pH 9. All strains were grown in Tryptic soy broth containing 6% of NaCl but inhibited in TSB containing 9% of NaCl except Shigella sonnei SG-73 after incubation for 18hrs at 37$^{\circ}C$. Selected strains grew during storage at 10 but did not grow at 4. The strains were survived in 1% pepton solution for 15 days at 37$^{\circ}C$. Viable cell of selected strains were decreased 45 log cycle after heat treatment for 30 mins at 6$0^{\circ}C$ but did not detect by heat treatment for 5 mins at 7$0^{\circ}C$.