• 보존과학연구
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• s.27
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• pp.23-42
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• 2006

This study is about gilt bronze ornament, that is from Deok Cheon-Ri in Gyeong Ju, of conservation treatment process and of scientific analysis. This relic gathered with soil around the relic by Polyurethane foam. While the relic got rid of soil, Took X-rays. As the result, we decided to process reconstruction as condition that the relic was dug up. After the conservation treatment processed, we made a frame to display the relic. Investigated manufacture techniques of the relic after the conservation treatment processed, and thenexecuted scientific analysis of the relic for a chemical experiment. A analysis of the results of components for composition layers using the SEM-EDS can be briefly summarized as below; Firstly, the average contents of outer, inner and body corrosion layer have a Cu-60.9~39.3wt% and analyzed a little impurities material which is Fe-0.5wt%.Secondly, the average contents of body have a Cu-99.7wt% which was using manufactured by pure copper. Thirdly, gold layer have a mercury of 9.5wt% which indicate that layer was manufactured by mercury amalgam gilding technique.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.1
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• pp.39-44
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• 2005

A sheet type of green body was made with the mixture of 60 wt% red clay, 20 wt% fly ash, and 20 wt% stone sludge. Indentations were made on the surfaces of sheets to investigate fracture rate of 1 to 5 mm artificial light-weight aggregates by various drying, breaking, and forming methods. Drying methods of green bodies were natural, electric oven, microwave, and fast drying by torch. Breaking methods of green bodies were ballmill Ⅰ, ballmill Ⅱ, free dropping in the box, and mechanical breaking with roller mill. The depth and width of indent on the surface of the sheet were varied and the thickness of green bodies was also changed to investigate effects of indentation on fracture rates. The highest fracture rate of 42 % among the various drying methods was obtained by microwave drying for 210 sec and the highest fracture rate of 65 % among the various breaking method was obtained by ballmill Ⅱ method. In forming method, an yield of larger aggregates than Ф = 5 mm decreased and that of smaller aggregates than Ф = 5 mm in creased with increasing depth of indentation (only in 3 mm thick green body)and with increasing thickness of green body. The size of aggregates was most homogeneous (by judging from the measurement of aspect ratio of 1 to 5 mm aggregates.) when 3 mm thick green body was rapidly dried by torch and was broken by ballmill Ⅱ method.

• Journal of Powder Materials
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• v.7 no.1
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• pp.6-11
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• 2000

Two kinds of Bi2Te3 powders, pure Bi2Te3/2vol.%ZrO2, have been prepared by a mechanical grinding process process. Effect of mixing of the powders on thermoelectric of the sintered body has been investigated by measuring Seebeck Coeffcient, specific electric resistivity and thermal conductivity. With an increase in the weight fraction of the Bi2Te3/2vol.%ZrO2 powder from 0 to 40wt.%. Especially, the figure of merit of the mixedBi2Te3 sintered body increases and thereafter dedreases above 40wt.%. Especially. the figure of merit of the mixed Bi2Te3 sintered bodies with mixing of Bi2Te3/2vol.%ZrO2 powder increased about 1.3time in comparison with the value of the specimen before mixing. Mixing of two kinds of Bi2Te3 powders which have different theramal and electric propertries with each other seemed to be useful methob to increase the figure of merit of Bi2Te3 sintered body.

• Journal of the Korean Ceramic Society
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• v.28 no.5
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• pp.415-421
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• 1991

Influence of Li2O.4B2O3 frit addition on the microstructure and thermal expansion properties of $\beta$-eucryptite ceramics was studied. With 1.0~10.0wt% frit addition, sintering temperature range was enlarged and densified body was obtained. Thermal expansion was increased from -6.67$\times$10-6 $^{\circ}C$-1 of pure sintered body to 1.03$\times$10-6$^{\circ}C$-1 of 6 wt% added body, but this increasement was accompanied by inhibition of thermal expansion anisotropy, so that improved microcracking property.

• Composites Research
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• v.25 no.6
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• pp.172-177
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• 2012

For the manufacture of low resistance Si-SiC composite, the properties of reaction sintering in the green body of various mixed ${\alpha}$-SiC powder size with the various carbon contents from 0wt% to 20wt% were investigated. The samples preparation was green body by CIP method under this condition, molten silicon infiltration process was conducted to reaction bonded silicon carbide. the results of sintered density, 3-point bending strength and resistance of analysis showed that varied carbon and silicon melt reacted to convert to fine ${\beta}$-SiC particle and the structure was changed to dense material. The amount of fine ${\beta}$-SiC particle was gradually increased as carbon content increase. According to mixed composite, it's mechanical and specific resistivity properties was strongly influenced by carbon content within 10wt% more then carbon content 10wt% was strongly influenced by phase transition.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.9
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• pp.1419-1426
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• 1990

The microstructure and electrical conductivity characteristics were examined for the Yttria Stablized Zirconia that were added Titania with the concentration of 0.02wt%, 0.05wt% and 0.1wt%. The stabilized cubic phase had not been changed. The obtained density of the sintered body was higher than 97% of the theoretical density as the grain growth and proe removal. And the highest density of 5.91g/cm**3 was obtained for 0.02wt% addition of TiO2. When 0.02 wt% TiO2 was added to YSZ, the electrical conductivity was 0.293.(\ulcorner.cm)**-1 and the limit of electrolyte regime Pn was 4x10**-28 atm. at 1, 100\ulcorner, respectively. Those were improved value compared with the electrical conductivity 0.107 (\ulcorner.cm)**-1 and Pn 1.5x10**-27atm. without adding TiO2.

• Journal of Veterinary Clinics
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• v.22 no.2
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• pp.108-113
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• 2005

This study was performed to investigate the growth rate, hematological and serological changes of the rats when they were fed with the high fat diets supplemented with or without the tannic acid for five weeks. Thirty-two Sprague-Dawley male rats(235.7\pm10.7g\;of\;body\;weight)$ were randomly divided into four groups, control group and three treatment groups(T1, T2 and T3). Rats in control group were fed with the high fat diet containing $15\%\;lard,\;1\%$ cholesterol and $0.5\%$ sodium cholate(wt/wt) which was modified from the formula of American Institute of Nutrition (AIN)-76 diet and rats in treatment groups were fed with above diet supplemented with $0.25\%(T1),\;0.5\%(T2)$ or $0.75\%(T3)$ of tannic acid(wt/wt), respectively. The supplementation of tannic acid(TA) did not affect the final body weight, gain of body weight and feed intake of rats in both control and treatment groups. The numbers of red blood cells, hemoglobin concentrations and hematocrit values in blood of rats showed no significant differences between control group and treatment groups. The glucose concentration and albumin/globulin(A/G) ratio of rats in treatment groups were slightly lower than that of control group without significance. The values of total protein, albumin and globulin showed no significant differences between control group and treatment groups. The values of total cholesterol, low density lipoprotein­cholesterol and atherogenic index in sera of rats in treatment groups were much lower than that of control group without significance. The values of triglycerides in sera of rats in T3 group were significantly lower than that of control group (p<0.05). The values of AST and ALT in sera of rats in T3 group were significantly lower than that of control group (p<0.05). Thus supplementation of tannic acid to high fat diet could be effective to reduce the serum lipid levels such as total cholesterol, high density lipoprotein-cholesterol and triglycerides which were regarded as to cause the cardiovascular diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.5
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• pp.337-341
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• 2009

Signal transducer and activator of transcription 4 (STAT4), a STAT family member, mediates interleukin 12 (IL12) signal transduction. IL12 is known to be related to calorie-restricted status. In the central nervous system, IL12 also enhances the production of nitric oxide (NO), which regulates food intake. In this study, the expression of neuronal NO synthase (Nos1), which is also related to food intake, was investigated in the hypothalamic areas of Stat4 knockout (KO) mice using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) histochemistry, a marker for neurons expressing Nos1 enzyme. Western blots were also performed to evaluate Nos1 and Fos expression. Wild-type Balb/c (WT group, n=10 male) and Stat4 KO mice (Stat4 KO group, n=8 male) were used. The body weight and daily food intake in the WT group were $22.4{\pm}0.3$ and 4.4 g per day, while those in the Stat4 KO group were $18.7{\pm}0.4$ and 1.8 g per day, respectively. Stat4 mice had lower body weight and food intake than Balb/c mice. Optical intensities of NADPH-d-positive neurons in the paraventricular nucleus (PVN) and lateral hypothalamic area (LHA) of the Stat4 KO group were significantly higher than those of the WT group. Western blotting analysis revealed that the hypothalamic Nos1 and Fos expression of the Stat4 KO group was up-regulated, compared to that in the WT group. These results suggest that Stat4 may be related to the regulation of food intake and expression of Nosl in the hypothalamus.

• Journal of Sericultural and Entomological Science
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• v.43 no.2
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• pp.109-115
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• 2001

Silk sericin protein was extracted by treatment with enzyme or NaOH solution from raw silk and culled-cocoon shell. The extracted sericin was characterized and examined the functional properties as well as subjective properties for its use as a soap and a body cleaner. The optimum extraction conditions on specimen are NaOH (0.02 wt.%) or enzyme, Flavourzyme 3% under N2 gas. Molecular weights of sericin was decreased by treatment with enzyme, Actinase, from 10,000-30,000 to 2,700-4,200. Sericin showed important bioactive properties, for instance, lowering effect on blood glucose and alcohol. Subjective test of sericin soap and body cleaner showed superior in washability, foamability, and skin hydration, etc., to commercial soap and body cleaner. Therefore, it is thought that silk sericin can be expected as the source of bioactive and skin-compatible materials.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1312-1316
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• 2007

Strip casted and rolled magnesium sheet is become exiting material for car manufacturer, due to its better formability and specific strength compare with conventional extruded sheet. TWB technology was attractive for car body designer, because it saves the weight of the car without strength loss. In this study, the laser welding performance of magnesium sheet was investigated for Mg TWB panel manufacturing. The material was strip casted and rolled magnesium alloy sheet contains 3 wt% Al and 1 wt% Zn (AZ31). Lamp pumped Nd:YAG laser of 2kW was used and its laser light was delivered by optical fiber of 0.6mm core diameter to material surface with focusing optics of 200mm focal length for TWB welding. The microstructure of weld bead was investigated to check internal defects such as inclusion, porosity and cracks. Also mechanical properties and formability were evaluated for press forming of car body. For the results, there was no crack but inclusion or porosity on weld at some conditions.The tensile strength of weld was over 95% of base metal. Inner and outer panel of engine hood were press formed and assembled at elevated temperature.