• Journal of the Korean Geotechnical Society
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• v.25 no.11
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• pp.27-38
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• 2009

In this study, a series of 1 g shaking table model pile tests were carried out in saturated dense and loose sand to evaluate dynamic p-y curves for various conditions of flexural stiffness of a pile shaft, acceleration frequency and acceleration amplitude for input loads. Dynamic p-y backbone curve which can be applied to pseudo static analysis for saturated dense sand was proposed as a hyperbolic function by connecting the peak points of the experimental p-y curves, which corresponded to maximum soil resistances. In order to represent the backbone curve numerically, empirical equations were developed for the initial stiffness ($k_{ini}$) and the ultimate capacity ($p_u$) of soils as a function of a friction angle and a confining stress. The applicability of a p-y backbone curve was evaluated based on the centrifuge test results of other researchers cited in literature, and this suggested backbone curve was also compared with the currently available p-y curves. And also, the scaling factor ($S_F$) to account for the degradation of soil resistance according to the excess pore pressure was developed from the results of saturated loose sand.

• Korean Journal of Food Science and Technology
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• v.37 no.3
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• pp.352-359
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• 2005

Uncertainty involved during determination of vitamin C content in infant formula was quantified by indophenol titration method. Uncertainty sources in measurand, such as purity, weight, final volume of standard, volume of standard solution used for titration, sample weight, final volume of sample, extraction solution used for titration, titration of extraction solution and standard solution by indophenol solution were identified and used as parameters for combined standard uncertainty based on Guide to the expression of uncertainty in measurement (GUM) and Draft EURACHEM/CITAC Guide. Uncertainty parameters of each source in measurand were identified as resolution, reproducibility and stability of chemical balance, standard material purity, repeatability, reproducibility, end point of titration, 1 mL pipet, 5 mL autopipet, and 100 mL mass flask. Each uncertainty component was evaluated by types A and B and included to calculate combined uncertainty. Analytical test result for traceability under laboratorial conditions using Certified Reference Material (CRM) test was certified as $108.4{\pm}1.7mg/100g$, which was within CRM certification range of $114.6{\pm}6.6mg/100g$. Uncertainty test result of vitamin C content of 5 g sampling was $56.7{\pm}2.44mg/100g$. Uncertainty could be reduced by identification of uncertainty sources and components related with vitamin C determination by indophenol titration method and by decreasing uncertainty sources and components.

• Macromolecular Research
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• v.17 no.12
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• pp.1021-1024
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• 2009

We successfully prepared high-flow polycarbonate (PC) by blending commercial PC with a low molecular weight PC oligomer. The oligomer was synthesized by the addition of a large quantity of mono functional phenol groups, and the chain end group was reacted with p-tertiary butyl phenol (PTBP) to block the reactivity. The viscosity average molecular weight ($M_v$) for the oligomer was about 4,000-5,000 g/mol, compared to ~19,000 g/mol for the PC blend obtained by blending 10 wt% of the prepared oligomer with the commercial grade PC ($M_v$ of 21,000 g/mol). The blended PC had a melt flow index of 45, which is 2.5 times higher, and a processing temperature that was $20^{\circ}C$ lower, than that of commercial grade PC having a similar $M_v$.

• Journal of the Korea Concrete Institute
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• v.28 no.5
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• pp.571-579
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• 2016

RS-LMC (Rapid Setting Latex Modified Concrete) has been widely used as repair material for bridge deck overlay or rehabilitation, because the overlaid pavement could be opened to the traffic after 3 hours of curing. Although the field performance of RS-LMC generally indicates that it has an excellent bonding to the substrate and shows a long term performance, the crack by vibration of vehicles have been happened on the overlay of bridges in technical reports. In this study, experimental research was carried out to evaluate the vibration properties of RS-LMC overlays by using P.S.T (Pavement Shaking Table). Total 12 specimens were tested and the variables are Latex-cement ratio (L/C) and amplitude of vibration. The result shows that the number of cracks and the total length of cracks are reduced as the increase of Latex-cement ratio (L/C) until 15%. And the crack occurs at a very small strain than the proposed values by Walter, D, G and design codes.

• Nutrition Research and Practice
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• v.16 no.3
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• pp.298-313
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• 2022

BACKGROUND/OBJECTIVES: The effectiveness of natural compounds in improving athletic ability has attracted attention in both sports and research. Gynostemma pentaphyllum (Thunb.) leaves are used to make traditional herbal medicines in Asia. The active components of G. pentaphyllum, dammarane saponins, or gypenosides, possess a range of biological activities. On the other hand, the anti-fatigue effects from G. pentaphyllum extract (GPE) and its effective compound, gypenoside L (GL), remain to be determined. MATERIALS/METHODS: This study examined the effects of GPE on fatigue and exercise performance in ICR mice. GPE was administered orally to mice for 6 weeks, with or without treadmill training. The biochemical analysis in serum, glycogen content, mRNA, and protein expressions of the liver and muscle were analyzed. RESULTS: The ExGPE (exercise with 300 mg/kg body weight/day of GPE) mice decreased the fat mass percentage significantly compared to the ExC mice, while the ExGPE showed the greatest lean mass percentage compared to the ExC group. The administration of GPE improved the exercise endurance and capacity in treadmill-trained mice, increased glucose and triglycerides, and decreased the serum creatine kinase and lactate levels after intensive exercise. The muscle glycogen levels were higher in the ExGPE group than the ExC group. GPE increased the level of mitochondrial biogenesis by enhancing the phosphorylation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) protein and the mRNA expression of nuclear respiratory factor 1, mitochondrial DNA, peroxisome proliferator-activated receptor-δ, superoxide dismutase 2, and by decreasing the lactate dehydrogenase B level in the soleus muscle (SOL). GPE also improved PGC-1α activation in the SOL significantly through AMPK/p38 phosphorylation. CONCLUSIONS: These results showed that GPE supplementation enhances exercise performance and has anti-fatigue activity. In addition, the underlying molecular mechanism was elucidated. Therefore, GPE is a promising candidate for developing functional foods and enhancing the exercise capacity and anti-fatigue activity.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.235-241
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• 2016

Grid-connected, large-capacity energy storage systems (ESS) can be used for peak load supply, frequency regulation, and renewable energy output smoothing. In order to confirm the capability of battery ESS to provide such services, 4MW/ 8MWh battery ESS demonstration facility was built in the Jocheon substation on Jeju Island. The frequency regulation technology developed for the Jocheon demonstration facility then became the basis for the 28MW and 24MW frequency regulation ESS facilities installed in 2014 at the Seo-Anseong and Shin-Yongin substations, respectively. The operation control systems at these two facilities were continuously improved, and their successful commercialization led to the construction of additional ESS facilities all over Korea in 2015. In seven (7) locations nationwide (e.g., Shin-Gimje and Shin-Gyeryeong), a total of 184 MW of ESS had been commercialized in 2016. The trial run for the new ESS facilities had been completed between April and May in 2016. In this paper, results of the trial run from each of the ESS facilities are presented. The results obtained from the Seo-Anseong and Shin-Yongin substations during a transient event by a nuclear power plant trip are also presented in this paper. The results show that the frequency regulation battery ESS facilities were able to quickly respond to the transient event and trial run of ESS is necessary before it is commercialized.

• Journal of Korean Society on Water Environment
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• v.22 no.5
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• Journal of Aquaculture
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• v.6 no.3
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• pp.213-219
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• 1993

Two studies were carried out: to compare commercial flounder diets (C1-C6) with a laboratory-formulated diet (S), and to evaluate moist pellet (MP) prepared with or without raw fish for olive flounder culture. In experiment I, three replicates of 20 fish (42 g in average) each were fed S or each of C1-C6 for four weeks at $17^{\circ}C. For experiment 2, three replicates of 400 fish (78 g in average) each were fed $100\%$ laboratory-formulated grower diet (G), 50\%\;G+50\;%$ frozen mackerel containing $70\%$ moisture or $50\%\;C6$ (the same diet as that used in Exp. 1) +$50\%$ frozen mackerel for six weeks. Weight gain of fish fed S was significantly (P< 0.05) higher than that of fish fed C2 or C3 (26.7 vs 15.4 or 17.5g/fish over the 4-week period, respectively). Feed efficiency was significantly (p<; 0.05) lower in fish fed C2 than in fish fed S but was not different (P> 0.05) between the fish fed Sand the other commercial diets. No significant differences in weight gain were found among the fish fed $100\%\;G,\;50\%\;G+50\%$ frozen mackerel or $50\%$ C6+frozen mackerel. The results of our studies indicate that most of the commercial flounder diets can be improved for better growth, when we compared these diets with a laboratory-formulated diet, and the growth of flounder fed MP containing no raw fish was as good as that of those fed MP prepared with raw fish.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.106-115
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• 1997

Objective : To evaluate the immunogenicity and safety afforded by the HG-II$^{(R)}$ recombinant hepatitis B vaccine given to healthy neonates and children and to find the influence of preceding BCG vaccination on immunogenicity. Methods : Three doses of recombinant hepatitis B vaccine with a dose of $10{\mu}g$ were given at birth, 1 and 6 months of age. This study was conducted in three hospitals (Gyeongsang National University Hospital(Group A), Kangnam General Hospital(Group B) and Younsei University Hospital(Group C)) from April, 1995 to June, 1996. Group A and Group B received 2nd dose of hepatitis B vaccine at 1 week after and before BCG vaccine, respectively. Antibidy levels, at 1 month after the 3rd dose of hepatitis B vaccine were determined by a radioimmunoassay. Results : 1) One hundred four infants and ten children were enrolled : 55 infants and 43 infants received 2nd dose of hepatitis B vaccine at 1 week after( After BCG Group) and before BCG vaccine(Before BCG Group), respectively. 2) The seropositive rate was 99.1%, and geometric mean anti-HBs titer was 131.2mIU/ml. 3) The geometric mean titers were 105.5mIU/ml and 162.8mIU/ml in After BCG and Before BCG Group, respectively(p<0.025). 4) Among 359 episodes of vaccination, the occurrence of systemic and local side reaction were reported in 7.8% and 1.4%, respectively. Conclusion : Recombinant hepatitis B vaccine(HG-II$^{(R)}$))was highly immunogenic and safe. The significantly lower geometric mean antibody titer in the BCG preceding group was observed. Well-designed controlled study with the large number of sample size will be required to show the influence of preceding BCG vaccination.

• Advances in Traditional Medicine
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• v.4 no.2
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• pp.87-90
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• 2004

The efficacy of Arque-Ajeeb (AA), a compound formulation of Unani medicine was investigated for antidiarrhoeal activity against barium sulphate-induced gut motility and castor oil-induced diarrhoea in rats. The control, standard and test groups of experimental animals were administered with distilled water (p.o.), lomotil (p.o.) and AA (0.007 ml and 0.014 ml/100 g, p.o.) respectively. Barium sulphate and castor oil were administered after 15 and 60 min respectively in each group of first and second experiment. The distance traveled by barium sulphate in small intestine was measured after 15 and 30 min of barium sulphate administration and diarrhoea was observed every 30-min for six hour after castor oil administration. Oral administration of AA caused significant reduction in diarrhoea. AA may have the potential to reduce the diarrhoea in rats.