• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1421-1426
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• 2014

To improve the inherent safety of the sodium-cooled fast reactor (SFR), the supercritical $CO_2$ ($S-CO_2$) Brayton cycle is being considered as an alternative power conversion system to steam the Rankine cycle. In the $S-CO_2$ system, a PCHE (printed circuit heat exchanger) is being considered. In this type of heat exchangers, diffusion bonding is used for joining the thin plates. In this study, the diffusion bonding characteristics of various austenitic alloys were evaluated. The tensile properties were measured at temperatures starting from the room temperature up to $650^{\circ}C$. For the 316H and 347H types of stainless steel, the tensile ductility was well maintained up to $550^{\circ}C$. However, the Incoloy 800HT showed lower strength and ductility at all temperatures. The microstructure near the bond line was examined to understand the reason for the loss of ductility at high temperatures.

• Korean Journal of Food Science and Technology
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• v.6 no.4
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• pp.193-198
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• 1974

The antioxidant activity of ground red pepper, ethyl alcohol extracts of ground red pepper peel and alcohol extracts plus organic acid was studied by using edible soybean oil as a substrate. All the substrates were stored in a dark place at $45.0{\pm}0.5^{\circ}C$ respectively. The results of the study were as follow: 1. Ground red pepper, black pepper and cassia exhibited slight antioxidant activity and there was no significant difference in antioxidant activity among them. 2. Although both ground red pepper peel and red pepper seed showed antioxidant activity, ground red pepper peel exhibited greater antioxidant activity than ground red pepper peel did. 3. Ethyl alcohol extracts of red pepper peel showed strong antioxidant activity, but the residue did not show the antioxidant activity. 4. The antioxidant activity of the ethyl alcohol extracts of red pepper peel increased in direct proportion to the concentration of the extracts. 5. In connection with the synergistic effect of organic acid to the ethyl alcohol extracts of red pepper peel, citric acid showed a very strong synergistic effect on the antioxidant activity of red pepper, while ascorbic acid showed a weak effect. On the other hand, phosphoric acid showed an accelerating effect on the oxidation of oils. 6. The maximum antioxidant activity of the ethyl alcohol of ground red pepper peel was observed at the citric acid concentration of 0.04%, when tested at various concentration of citric acid.

• Science of Emotion and Sensibility
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• v.15 no.1
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• pp.141-148
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• 2012

This study investigated the structural coloration and fabric hand of the caustic reduced fabrics for emotional garment using structural color yarns, which was spun by 37 alternating nylon and polyester layers capable of producing basic colors using biomimetic technology. The colorations of the three kinds of structural color yarns were confirmed using multi angle spectro-photometer, and their triangular cross sections composed with 37 alternating nylon and polyester layers were measured using SEM and were discussed with layer length in relation with coloration and spinning conditions were also set up. The apparent color difference and reflectance of the three kinds of fabrics with different density and weave pattern were analysed as ranging from 400nm to 700nm. The optimum fabric structural design which is made by warp and weft densities(194ends/in ${\times}$ 105picks/in) and caustic reduction condition by $100^{\circ}C$ temperature and 60minutes with NaOH, 20g/l solution were decided through analysis of the mechanical properties and fabric hands of these three kinds of fabrics treated with 3 kinds of the caustic reduction conditions. And it was shown that the rate of caustic reduction was increased from 13% to 23% with increasing temperature and time of caustic reduction. The extensibility, bending rigidity and shear modulus of caustic reduction treated fabrics were decreased by treatment of caustic reduction, on the other hand fabric compressibility was increased. And it was shown that the hand value of specimen number one which was treated with temperature $100^{\circ}C$ and time 60minute was the best and the hand of this fabric was better than that of Morpho $fabric^{(R)}$ made by Teijin co. Japan.

• Journal of Nutrition and Health
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• v.21 no.4
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• pp.242-252
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• 1988

In vivo effects of leucine on skeletal muscle protein synthesis in fed and I-day food deprived young rats were examined. Animals assigned to leucine group were given a single i.p. injection of 80 or 160flmoles of leucine while control group animals were saline sham injected. The rate of protein synthesis was measured by the amount of $^{14}\textrm{C} incorporated into muscle protein after a single injection of $^{14}\textrm{C}-tyrosine, IO$\mu$ Ci/l00g B.W. Examined muscles were two different types of hind limb muscles. the oxidative solues and the glycolytic EDL and plantaris. Administered leucine elevated the concentration of free leucine in soleus muscles by 4-6.8 times the normal level. A massive dose of leucine, 160 flmoles, stimulated protein synthesis in the EDL and plantaris by 24 %, 29 % respectively of straved rats. The soleus of I-day food deprived rats and both types of muscles in fed rats did not respond to the injected leucine. The synthesis rate of the EDL and plantaris was supressed to one-half of the normal while the soleus that was not stimulated by leucine maintained a relatively normal rate, 78 %, of protein synthesis after I-day of food deprivation. Thus, in vivo stimulatory effect of leucine appears to be not a general phenomenon but to be related to the degree of catabolic condition developed by stress such as food deprivation. Although anabolic effects of leucine observed in this study was limited, any applicability of this special property of leucine to human subjects for the purpose of protein sparing in skeletal muscles remains to be examined.

• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.220-228
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• 2003

This study was to examine the thermodynamic features of polyelecrolytic adsorption of polyamidoamine-epichlorohydrin(PAE) in a papermaking wet-end. The PAE adsorption experiments were conducted in a stirred jar containing an aqueous fibrous suspension and evaluated in terms of Langmuir and Freundlich parameters. The electrokinetic property of a stock was examined by measuring the zeta potential of each colloidal suspension. The polyelectrolytic PCD titration was employed to determine the adsorbed amounts of PAE polymer. The zeta potential of a stock, being varied significantly depending upon the addition of PAE polymer, showed initially a sharp increase and later an exponential decay as a function of time . The PAE adsorption exhibited a pseudo-Langmuir adsorption behavior at$20^{\circ}C$ , whereas its Freundlich power(v) increased in a proportional way at an elevated temperature. The train numbers calculated on the basis of adsorption thermodynamics were 7 to 8. The length of the extended loop of PAE was calculated as 215 nm at $20^{\circ}C$ and increased at a rate of 9% at every $10^{\circ}C$ rise in temperature. The PAE adsorption was proven to be an exothermic physisorption with the estimated adsorption enthalpy of -27 to -29 kJ/mol.

• Progress in Superconductivity
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• v.7 no.1
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• pp.97-101
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• 2005

Bi-22l2 tubes for fault current limiter (FCL) were fabricated by centrifugal melting process. $SrSO_4$ ($10\;wt.\;\%$) was added to Bi-2212 powder to lower the melting point of Bi-22l2 and to improve the mechanical properties. The BSCCO powder was completely melted at $1300\;^{\circ}C$ using the RF furnace and then poured into rotating steel mold. The steel mold, preheated at $450\;{\circ}C{\sim}550^{\circ}C$ for 2 hour was rotated at $1020{\sim}2520\;RPM$. The solidified BSCCO tube was cooled down to room temperature in the furnace for 48 hours and separated from the mold between Bi-2212 and the mold. $ZrO_2$ solution was used to separate it easily from the mold and Ag tape was attached in the mold inner wall of the mold to analysis electrical property. Bi-22l2 tube was often cracked when the cooling rate was high. BSCCO tubes with $70{\Phi}{\times}100\;mm,\;50{\Phi}{\times}100\;mm$ and $30{\Phi}{\times}150\;mm$ size were fabricated by centrifugal melting process. The $J_{c}s$ of tubes with $50{\Phi}{\times}100\;mm{\times}4.0\;t$ and $50{\Phi}{\times}100\;mm{\times}4.l\;t$ were 178 and $74.2\;A/cm^2$ at 77K, respectively. The processing condition for Bi-2212 tube fabrication was investigated using XRD and SEM analyses.

• Food Science of Animal Resources
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• v.23 no.3
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• pp.209-214
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• 2003

This study was carried out to investigate the influence of dietary xanthophylls(lutein and apocarotenoic acid ethyl ester) supplementation on the antioxidation of broiler meat. The broilers fed with 10 ppm or 20 ppm xanthophylls were raised for 6 weeks and then slaughtered. The broiler meats were stored at 3$^{\circ}C$ for 9 days and frozen at -18$^{\circ}C$ for 4 months until analysis, respectively. The pH of all treatments significantly(p<0.05) increased during the storage periods. The pH of the thigh was higher than that of the breast. TBARS (thiobarbituric acid reactive substance) and POV(peroxide value) were higher in thigh than breast. All meats from broiler fed with lutein and apocarotenoic acid ethyl ester(apo-ester) had greater antioxidant properties during the storage period than control meat(p<0.05). Antioxidant activity of dietary xanthophylls supplementation was more effective in thigh than breast, and in broiler meats during frozen storage than chilled storage. The higher concentration of xanthophylls in feed, the more inhibition of lipid oxidation in meat during storage. The meat from broiler fed with 20 ppm of lutein showed the highest antioxidant property during both refrigerated and frozen storage although there was no significant difference between lutein and apo-ester(p>0.05). Consequently, this results indicated that the antioxidant activity of dietary xanthophylls(lutein and apocarotenoic acid ethyl ester) supplementation was more effective.

• Culinary science and hospitality research
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• v.19 no.5
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• pp.23-35
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• 2013

This study aimed to determine the physicochemical and sensory qualities of yogurt dressing prepared with Bokbunja juice(0, 10, 20, 30 and 40%). As the amount of added Bokbunja juice increased, contents of organic acids(citric acid, tartaric acid, malic acid, succinic acid and acetic acid) increased. The viscosity of the control group(8306.67 cP) was higher than those of the others(1633.33~6913.33 cP). The pH of the control group(3.96) was higher than those of the others(3.90~3.85). The sweetness of the control group(14.43) was lower than 10% Bokbunja juice added group(14.93). Color L decreased significantly, whereas a value and b value increased significantly with more Bokbunja juice added. DPPH radical scavenging activity of the control group was 5.84%, whereas those of yogurt dressing samples with Bokbunja juice ranged from 39.72~88.17%. The sensory property results showed that yogurt dressing with 30% Bokbunja juice added group had the highest value in terms of color, flavor, taste, mouth feel, and overall acceptability. Overall, the result of this study indicates that the yogurt dressing containing 30% of Bokbunja juice was most preferred among the groups.

• Corrosion Science and Technology
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• v.14 no.2
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• pp.99-105
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• 2015

The structures of reinforced concrete have been extensively increased with rapid development of industrial society. Futhermore, these reinforced concretes are easy to expose to severe corrosive environments such as seawater, contaminated water, acid rain and seashore etc.. Thus, corrosion problem of steel bar embedded in concrete is very important in terms of safety and economical point of view. In this study, specimens having six different coating thickness (W/C:0.5) were prepared and immersed in flowing seawater for five years to evaluate the effect of coating thickness and immersion time on corrosion property. The polarization characteristics of these embedded steel bars were investigated using electrochemical methods such as corrosion potential, anodic polarization curve, and impedance. At the 20-day immersion, the corrosion potentials exhibited increasingly nobler values with coating thickness. However, after 5-yr. immersion their values were shifted in the negative direction, and the relationship between corrosion potential and coating thickness was not shown. Although 5-yr. immersion lowered corrosion potential, 5-yr. immersion did not increase corrosion rate. In addition, after 5-yr. immersion, the thinner cover thickness, corrosion current density was decreased with thinning coating thickness. It is due to the fact that ease incorporation of water, dissolved oxygen and chloride ion into a steel surface caused corrosion and hence, leaded to the formation of corrosion product. The corrosion product plays the role as a corrosion barrier and increases polarization resistance. The corrosion probability evaluated depending on corrosion potential may not be a good method for predicting corrosion probability. Hence, the parameters including cover thickness and passed aged years as well as corrosion potential is suggested to be considered for better assessment of corrosion probability of reinforced steel exposed to partially or fully in marine environment for long years.

• Korean Journal of Materials Research
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• v.22 no.2
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• pp.61-65
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• 2012

A $Li_2O-2SiO_2$ ($LS_2$) glass was investigated as a lithium-ion conducting oxide glass, which is applicable to a fast ionic conductor even at low temperature due to its high mechanical strength and chemical stability. The $Li_2O-2SiO_2$ glass is likely to be broken into small pieces when quenched; thus, it is difficult to fabricate a specifically sized sample. The production of properly sized glass samples is necessary for device applications. In this study, we applied spark plasma sintering (SPS) to fabricate $LS_2$ glass samples which have a particular size as well as high transparency. The sintered samples, $15mm\phi{\times}2mmT$ in size, ($LS_2$-s) were produced by SPS between $480^{\circ}C$ and $500^{\circ}C$ at 45MPa for 3~5mim, after which the thermal and dielectric properties of the $LS_2$-s samples were compared with those of quenched glass ($LS_2$-q) samples. Thermal behavior, crystalline structure, and electrical conductivity of both samples were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and an impedance/gain-phase analyzer, respectively. The results showed that the $LS_2$-s had an amorphous structure, like the $LS_2$-q sample, and that both samples took on the lithium disilicate structure after the heat treatment at $800^{\circ}C$. We observed similar dielectric peaks in both of the samples between room temperature and $700^{\circ}C$. The DC activation energies of the $LS_2$-q and $LS_2$-s samples were $0.48{\pm}0.05eV$ and $0.66{\pm}0.04eV$, while the AC activation energies were $0.48{\pm}0.05eV$ and $0.68{\pm}0.04eV$, respectively.