• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.11a
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• pp.1.1-4
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• 1995

In this study, PLZT thin films in AFE region prepared by sol-gel processing were investigated. And PLZT stock solutions were spin-coated on ITO-glass. The PLZT thin films were annealed by RTA. Hysteresis curves, dielectric characteristics and optical transmittances were measured in order to investigates the characteristics far the thin films. The PLZT thin films were crystallized at 750$^{\circ}C$ for 5 mimutes by RTA and the rosette structure composed of perovskite observed in the thin films. In case La content was 2/90/10 antiferroelectric-ferroelectric phase boundary was 2/90/10 PLZT thin film, and its hysteresis curve was good for application of optical information storage.

• Journal of Ginseng Research
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• v.14 no.3
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• pp.442-446
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• 1990

As a part of studies on the quality control of crude drug-drink preparations, ginger components were identified by TLC and 6-gingerol was determined quantitatively by HPLC. Ginger components were identified by TLC with benzene/acetone (4:1, v/v, on silica gel plate by spraying a vanillinsulfuric acid reagent. 5-Gingerol contents were determined at 280 nm by HPLC on Lichro CART RP-18 column with acetonitrile/wate(38:62, v/v). Its transfer rate in the 3 types of crude drug extract drinks was 65.4-85.1% compared to the content in the ginger extract.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.632-635
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• 2003

[ $(Ba,Sr,Ca)TiO_3$ ] powders, prepared by the sol-gel method, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen printing techniques on alumina substrates. The dielectric properties were investigated for various composition ratio and $Nb_2O_5$ doping contents. All the BSCT thick films, sintered at $1420^{\circ}C$, showed the typical XRD patterns of a perovskite polycrystalline structure. The Curie temperature and the relative dielectric constant decreased with increasing Ca content and $Nb_2O_5$ doping amount. The relative dielectric constant, dielectric loss and tunability of the BSCT(50/40/10) thick films doped with 1.0wt% $Nb_2O_5$ were 1410, 0.65% and 17.29% respectively.

• Journal of Ginseng Research
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• v.15 no.1
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• pp.1-5
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• 1991

For the quality control of crude drug drink preparations, methods for identification of cinnamon components and quantitative determination of cinnamic acid were established. Cinnamon components were identified by TLC with benzene/ethyl acetate (1:1, v/v) on silica gel plate by spraying p-anisaldehyde-sulfuric acid. Cinnamic acid contents were determined at UV 280 nm by HPLC on $\mu$-Bondapak Cls column with acetonitrile/water/acetic acid (40:60:2, v/v). Recoveries of cinnamic acid in three crude drug drink preparations were between 84.1-90.2% compared to the content of the cinnamon extract.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.238-238
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• 2001

15% Syn M, sintered mullite(SM) and fused mullite(FM) was added to produce high alumina refractory materials. Mullite content of SM, FM and Syn M was 93.17%, 86.79%, 97.57% repectively. Mechanical properties of specimens (added 15wt% mullite) ware investigated to be flexural strength 338.60MPa, compressive stcngth 9,427kgf/㎠. But the specimen which imported mullite was added showed 5~10%l lower stregth than syn M added.

• Macromolecular Research
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• v.11 no.3
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• pp.172-177
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• 2003

Biphenyltetracarboximide-phenylene diamine polyimide/silica-titania ternary hybrid composites were Prepared by thermal imidization and sol-gel reaction. Fluorescence spectroscopic, scanning electron microscopy, and atomic force microscopy studies revealed that the addition of small amount of titania showed profound effects on the microstructure and photophysical behaviors of polyimide/silica hybrid composites, when the content of silica-titania mixture was small or when the ratio of silica to titania in the mixture was high.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.926-928
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• 1999

Treeing inhibitors of barbituric acid derivatives effects on the electrical properties of crosslinked low density polyethylene under radiation environments were investigated. The electrical parameters for tree inception voltage, AC breakdown strength, volume resistivity, capacitance and dissipation factor at 1MHz and thermoluminescence, gel content measurements were discussed as a function of irradiated dosages. From the results, barbituric acid among the treeing inhibitors was shown the best treeing and radiation resistance.

• Korean Journal of Pharmacognosy
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• v.32 no.2 s.125
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• pp.153-156
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• 2001

The methods for isolation and quantitative determination of dioscin, a spirostanol triglycoside, from the roots of Smilax china have been developed. Isolation of dioscin was achieved by silica gel and RP-18 chromatography. The HPLC method used for quantitative determination of dioscin enabled the standardization of the crude drug. It suggests that the content of dioscin in Smilax china should be above 0.01%.

• The Korean Journal of Food And Nutrition
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• v.12 no.5
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• pp.508-512
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• 1999

In order to qualify and quantify carotenoid pigment of pumpukin were analyzed by HPLC column chromatography and spectrophotometry. Eightyseven percent of total carotenoids in the pumpkin was in the fiber amounting 65.33mg%. however flesh and skin contained 6.61 and 3.31mg% respectvely. A silica gel column chromatography of the carotenoids produced 2 different peaks. The components eluted in peak II showed blue color when treated with hydrochloric acid. The fact suggested it contained epoxide and the component in peak II was a monol. By the separation with HPLC. $\alpha$ and $\beta$-carotene were the major compounds in the carotenoids. In fiber the total $\beta$-carotene content was 1.6 times higher than in the flesh and skin. The fiber contained less unidentified compounds than other part which contained 27.3~32.8%.

• Textile Coloration and Finishing
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• v.16 no.1
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• pp.53-58
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• 2004

The preparation of responsive fibers from acrylic fibers is studied. Various responsive fibers, such as fibers which change their color on exposure to light or with change in temperature, have been developed and are used commercially However, the responsive material in these fibers are not the fiber itself but chemicals in microcapsules attached to the fibers by finishing, and few fibers exhibit responsive properties by itself. The partial hydrolysis of polyacrylonitrile fibers to obtain pH responsive fibers is presented in this paper. Partial hydrolysis was effected by control of the concentration of the sodium hydroxide used in the hydrolysis, hydrolysis temperature and time. The degree of hydrolysis was evaluated by nitrogen content of the hydrolyzed fibers and their response, change in length, to aqueous solutions of varying pH was studied by continually changing the pH. Significant changes in lengths with pH were observed and the gel transition behavior varied with the conditions of hydrolysis. The hysteresis of the length change was also studied to evaluate the possibilities of using hydrolyzed acrylic fibers as pH sensors.