• Composites Research
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• v.32 no.2
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• pp.90-95
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• 2019

Sloshing impact loads on liquefied natural gas (LNG) carr iers are the main issue of damage to the insulation system in LNG cargo containment system (LNG CCS). The damage to the insulation system would be fatal in maintaining a temperature-savings environment in LNG CCS. The typical method is to enhance the insulation materials that can maintain a constant cryogenic temperature. Insulation materials consist of polyurethane foam and plywood, an adhesive for bonding these two materials. This study intends to improve the absorption energy of the material when the impact load is applied by creating a glass bubble/epoxy composite resin as part of the insulation. The experimental scenarios consider the effect of temperature ($20^{\circ}C$, $-163^{\circ}C$), glass bubble weight fraction in epoxy resin through free fall experiments. Experiments have shown that if the glass bubble additive reaches 20 wt.%, the cryogenic absorption energy is a maximum performance and that 0 wt.% has a maximum ambient absorption energy. However, the agglomeration has been occurred due to deterioration of the stirring performance if weight fraction was 20 wt.% and the result of 0 wt.% have been revealed that ambient absorption energy is significantly lower.

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.47-56
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• 2021

The cryosuction (negative pore pressure) in freezing soils causes groundwater migration from the frozen fringe to freezing front for ice lens formation. Frost heave and heaving pressure by ice lens cause damage to ground infrastructure. In order to prevent damage by the frost heave, various frost susceptibility criteria have been proposed. The SP (Segregation Potential) is the most widely used classification criterion for frost susceptibility in cold regions. The expansion of the ice lens by the migration of the groundwater is a key role in frost heave mechanism, and thus it is necessary to evaluate the hydraulic conductivity. In this paper, soil mixtures of coarse-fines (sand-silt) were prepared in various weight fractions and used for frost heave and column permeability test. For each case, the SP and the hydraulic conductivity were derived and correlations were analyzed. As a results, the transition threshold of the SP and the hydraulic conductivity were shown at 20% and 50% of the silt weight fraction, respectively. Although there are difference between these transition thresholds, these two coefficients show a specific correlation. In the future, additional study should be conducted for detailed analysis of the threshold transition values between SP and hydraulic conductivity.

• Tunnel and Underground Space
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• v.7 no.2
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• pp.100-107
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• 1997

In case of a fire outbreak in a uni-directional road tunnel, the flow of traffic immediately behind the fire disaster will be stalled all the way back to the entrance of the tunnel. Furthermore, when the vehicle passengers try to flee away from the fire toward the entrance of the tunnel, the extremely hot fume that propagates in the same direction will be fatal to the multitudes evacuating, but may also cause damage to the ventilation equipments and the vehicles, compounding the evacuation process. This paper will present the 3-dimensional modelling analysis of the preventive measures of such a fume propagation in the same direction as the evacuating passengers. For the analysis, the fire hazard was assumed to be a perfect combustion of methane gas injected through the 1 m X 2 m nozzle in the middle of the tunnel, and the product of $CO_2$ as the indicator of the fume propagation. From the research results, when the fire hazard occurred in middle of the 400 m road tunnel, the air density decreased around the fire point, and the maximum temperatures were 996 K and 499 K at 210 m and 350 m locations, respectively, 60 seconds after fire disaster occurred, when the fumes were driven out only towards the exit-direction of the tunnel. By tracing the increase of $CO_2$ level over 1% mole fraction, the minimum longitudinal ventilation velocity was found to be 2.40 m/sec. Furthermore, through Analysis of the temperature distribution graphs, and observation of the cross-sectional distribution of $CO_2$ over 1% mole fraction, it was found that the fume did not mix with the air, but rather moved far in a laminar flow towards exit of the tunnel.

• Preventive Nutrition and Food Science
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• v.16 no.2
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• pp.127-134
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• 2011

The purpose of this study was to purify antioxidant substances from steamed squid extract (SSE). The yield of SSE was 8% by dry weight. The approximate compositions of SSE proteins, lipids, moisture, carbohydrate and ash were 64.95%, 1.69%, 7.23%, 4.44% and 21.69%, respectively. The major amino acids in SSE were taurine (29.17%), glycine (20.33%), alanine (12.51%), and glutamic acid (9.83%). Antioxidant activities were evaluated using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, which was measured as 24.7% at 1.0 mg/mL. Four SSE fractions were isolated by Sephadex G-25 gel chromatography; the F2 fraction showed the highest DPPH radical scavenging activity. The F2 fraction was separated by reverse-phase high performance liquid chromatography (HPLC) using an octadecylsilane (ODS) column, yielding a purified antioxidant substance with a DPPH radical scavenging activity of 64.41% at 1.0 mg/mL, representing a 2.64-fold increase in the scavenging activity of SSE purified by the 3-step procedure. The amino acid compositions showed that purified SSE was rich in taurine, glycine, glutamic acid and alanine. The purified SSE significantly elevated 2',7'-dichlorodihydrofluororescein diacetate (DCFH-DA) fluorescence probe, which confirms its effective radical scavenging potential in cellular ROS. In addition, the SSE significantly inhibited oxidative damage of purified genomic DNA. These results suggest that a purified antioxidant substance from SSE can be used as a potential natural compound-based antioxidant in the functional food and pharmaceutical industries.

• Journal of Nutrition and Health
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• v.36 no.8
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• pp.793-800
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• 2003

This study was conducted to investigate the antioxidative effects of Paeonia lactiflora (PL) seeds on antioxidative defense system and lipid peroxidation of liver in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100 $\pm$10g were randomly assigned into five experimental groups fed 0.5% cholesterol ; HC group which was not supplemented PL seeds extract, 0.1% methanol extract diet group (MP1 group), 0.2% methanol extract diet group (MP2 group), 0.05% ether-souble fraction diet group (EP1 group) and 0.1 % ether-souble fraction diet group (EP2 group). Experimental diets were fed ad libitum to the rats for 3 weeks. The activity of hepatic superoxide dismutase (SOD) was not significantly different among all the high cholesterol diet groups. The hepatic glutathione peroxidase (GSHpx) activity in MP2 group was increased to 27% compared to HC group. The activity of hepatic catalase (CAT) was not significantly different among the all high cholesterol diet groups. The hepatic glutathione S-transferase (GST) activity in the EP1 and EP2 groups were increased to 12% and 13%, respectively, as compared to HC group. The levels of hepatic TBARS in the MP1, MP2, EP1 and EP2 groups were reduced by 18%, 21%, 20% and 23%, respectively, as compared with HC group. The contents of lipofuscin in liver was not significantly different among all the experimental groups. The results indicated that PL seeds extract may be reduced oxidative damage by activating antioxidative defense system of hepatic in rats fed high-cholesterol diets. (Korean J Nutrition 36(8): 793∼800, 2003)

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.990-996
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• 2003

This study was conducted to investigate the effects of Forsythia viridissima Lindl. (FVL) on antioxidative defense system and lipid peroxidation of liver in rats fed high-cholesterol diet. Sprague-Dawley male rats weighing 100 $\pm$ 10 g were randomly assigned into five experimental groups fed 0.5％ cholesterol ; HC group which was not supplemented FVL extract, 0.05％ methanol extract diet group (MSI group), 0.1％ methanol extract diet group (MS2 group), 0.025％ ethylacetate-souble fraction diet group (ES1 group) and 0.05％ ethylacetate-souble fraction diet group (ES2 group). Experimental diets were fed ad libitum to the rats for 3 weeks. The hepatic xanthine oxidase (XOD) activity in the MS2 group was decreased to 20％ as compared to HC group. The activities of hepatic superoxide dismutase (SOD) and catalase (CAT) were not significantly different among all the high cholesterol diet groups. The hepatic glutathione peroxidase (GSHpx) activity in MS2, ES2 groups were significantly increased as compared to HC group. The hepatic glutathione S-transferase (GST) activity in the MS2 group was increased to 20％ as compared to HC group. The levels of hepatic TBARS in the MS1, MS2, ES1 and ES2 groups were reduced by 13％, 21％, 13％ and 21％, respectively, as compared with HC group. The contents of lipofuscin in liver tissue was not significantly different among all the experimental groups. The results indicate that FVL extract may reduce oxidative damage by activating antioxidative defense system of liver in rats fed high-cholesterol diets.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.784-790
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• 2003

Present investigation shows the analysis results for ceramic reinforced metal matrix composite under uniaxial transverse tensile loading. The resulting deformation, the projected damage type, and stress-strain behavior were computed depending on microstructure details such as the type of periodic reinforcement array, and the type of interface bonding. A two-dimensional finite element analysis was conducted based on the unit-cell of square, hexagonal, or diagonal periodic away For composite with strong interface bonding, the transverse stress vs. strain curve was generally increased with the increase of the ceramic volume fraction. For the composite with weakly bonded interface, however, the transverse stress vs. strain curve was reduced against the ceramic volume fraction. The decrease was caused by the interface debonding-induced stiffness reduction of the composite. For the composite of weakly bonded interface, the relative reduction rate in the final limit stress for hexagonal array was larger than that for square array. Outcome of the present study was compared favorably with the published literature data.

• Advances in Traditional Medicine
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• v.7 no.5
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• pp.534-539
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• 2008

Shenqi-wan, Oriental herbal medicine formulation, has traditionally been used for the treatment of delayed mental and physical development in children, complications of diabetes, and glomerulonephritis. In the present study, we investigated the protective effect of the aqueous extract of Shenqi-wan and its fractions against N-methyl-D-aspartate (NMDA)-induced exitotoxicity in rat hippocampal CA1 neurons. Fractions were elucidated at 0 - 10 min, 11 - 20 min, and 21 - 30 min by using gravity column chromatography method. In the present results, treatment with NMDA on cultured hippocampal slices induced neuronal death in the hippocampal CA1 region. Pretreatment with the Shenqi-wan did not exerted protective effect, however its fractions suppressed NMDA-induced neuronal damage. The fraction elucidated at 11 - 20 min showed the most potent protective effect. These results revealed that effective substances of the Shenqi-wan against NMDA-induced excitotoxicity may exist mainly in the fraction elucidated at 11 - 20 min.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.327-335
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• 2010

We reported previously that the administration of Korean red ginseng water extract (KRG-WE) protected the guinea pig testis against damage induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (a potent endocrine disruptor). We also found that crude saponin from ginseng was the active ingredient responsible for this protection. Here, we examined the biological role of KRG-WE in an animal model of age-induced dysfunction of spermatogenesis. Twenty-four male Sprague-Dawley (six 2-month-old and eighteen 12-month-old) rats were used. The young and old control groups received only vehicle. The ginseng saponin (GS)- and KRG-WE-treated groups received GS (40 mg/kg body weight/day) and KRG-WE (200 mg/kg body weight/day), respectively, for 4 months. The number of cells, Sertoli cell index, Johnsen's score, and sex hormone levels decreased significantly with age. However, the administration of KRG-WE and GS markedly improved the number of germ cells, seminiferous tubular size, and Johnsen's score in the old rats. Ginseng produced a distinct testicular histological improvement in old rats. KRG-WE and GS elevated testosterone levels, while attenuating the aberrant increase in follicle stimulating hormone and luteinizing hormone levels. Sperm kinematics evaluated by a computer-assisted sperm analyzer demonstrated improvement in the percentage of motile sperm, progressive sperm motility, and curvilinear velocity associated with sperm quality, supporting the beneficial role of red ginseng in senile spermatogenesis. Overall, the total water extract had a more potent effect than the corresponding saponin fraction. In conclusion, Korean red ginseng rejuvenated age-induced testicular dysfunction. Additionally, the total water extract was more potent than the corresponding saponin fraction.

• Journal of Applied Biological Chemistry
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• v.61 no.3
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• pp.283-290
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• 2018

In this study, we verified the 1-1-diphenyl-2-picryl-hydrazyl radical scavenge, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenge, elastase, tyrosinase inhibitory effect by using the solvent fractions of Maekmoondong-tang hot water extract. As a result, the ethyl acetate fraction (MW-EA) showed the highest inhibitory activity. In cell-based assays, MW-EA treatment confirmed a 34% ($100{\mu}g/mL$) efficacy in reactive oxygen species inhibitory activity, and at the same concentration, MMPs showed more than 50% inhibition and tyrosinase inhibited 25% ($50{\mu}g/mL$). Therefore Maekmoondong-tang is considered high development potential as a material to improve the skin.