• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.335-339
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• 2007

In order to overcome the problem of poor hardness of transparent polycarbonate (PC) sheets, organic-inorganic hybrid hard coating solutions, which show a high refractive index above 1.58, were made by the sol-gel method. These hybrid coating solutions were obtained from mixture of titanium tetraisopropoxide (TTIP), and (3-glycidoxypropyl)trimethoxysilane (GPTMS). The PC sheets were spin-coated, and cured at $120^{\circ}C$ for 2 hr. Change of refractive index in the range of 1.53-1.61 was obtained by varying the GPTMS content. The refractive index of the coated film decreased with increasing the GPTMS content, while the pencil hardness of the coated film was found to increase with increasing the GPTMS content.

• Journal of the Korean Ceramic Society
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• v.28 no.12
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• pp.943-952
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• 1991

Lead zirconate titanate(PZT) powders and thin films were prepared from an alkoxide-based solution by sol-gel method. Gelation of synthesized complex solutions, pyrolysis and crystallization behaviors of the dried powder were studied in accordance with a water content and a catalyst. PZT thin films were formed by spin-casting method on silicon and platinum substrates, and characterized. Ester produced from the reactions was completely removed when drying of the gel was finished. Pyrolysis property of the dried PZT gels were changed in order water content, class of catalyst, and quantity of catalyst. Crystalline Pb phase was transiently formed near 250$^{\circ}C$. Basic catalyst is good additive for a formation of perovskite phase in the films, and acidic catalyst for a densified film structure. By the analysis of RBS, Pb element in the PZT films were diffused into silicon substrate, and the pores, may be produced due to local densification around some grains in the films, make an origin of fault in microstructure when holding time goes to be longer at 700$^{\circ}C$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.2
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• pp.178-183
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• 2004

PBT thin film was known to be a representative for the FeRAM devices because of its good ferroelectric proporties and the ease in fabricating the thin film. However, there have been several problems such as polarization fatigue and leakage current in memory devices with a PZT thin film. In this study, Sm-dolled PZT thin films were fabricated by the so1-gel method, and their ferroelectric and dielectric proportrics were compared as a function of Sm content. We investigated the effect of the Sm dopant on structural and electrical properties of PZT film. Sm-doped PZT thin films on the Pt/Ti/SiO$_2$/Si substrates have been prepared by a sol-gel method. The remanent polarization and coercive field decreased with increasing the concentration of Sm. The dielectric constant and dielectric loss decreased with Increasing Sm content. Sm-doped PZT thin films showed improved fatigue characteristics compared to the undoped PZT thin film.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.48-51
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• 1997

(Pb. La)TiO$_3$ thin films were fabricated by sol-gel Processing and spin-coated on the Pt substrate. The spin-coated PLT films were sintered at 75$0^{\circ}C$ for 5min by rapid thermal ann La content dependence of the electrical properties of the PLT thin films are discussed. Wit La mole% from 20 to 36mo1e%. the dielectric constant of the PLT thin films decreased f 570. P-E hysteresis loops changed from ferroelectric to paraelectric. and the charge storage charging time decreased. The Curie Point decreased with increasing La content. The leak density also decreased and La 36mo1% species shows mood characteristics less than 10- electric field 500 (KV/cm) Because of the broad range of composition-controlled ferroelectric PLT thin films are suitable for memory application.

• KSBB Journal
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• v.17 no.1
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• pp.54-58
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• 2002

Curdlan gel containing various hydrophobic materials was prepared. The homogenized suspension of curdlan and hydrophobic materials was healed at $100^{\circ}C$. The curdlan gel can contain hydrophobic material up to 27%(v/v). When gel was compressed, only water in the gel was removed. When immersed in water, the dried gel absorbed water and became the original wet gel. The syneresis of gel decreased with the concentration of hydrophobic material added. DHA content of dried gel was about 90%. $\beta$-cyclodextrin inclusion complexes containing DHA were prepared with addition of water and ethanol. X-ray diffractograms of complexes showed a specific peak at 7-$8^{\circ}C$ and FT-IR spectrum of complex showed a specific C=O peak at $1745\textrm{cm}^{-1}$. Inclusion complex containing DHA was microcapsulated with curdlan and pullulan.

• Journal of the Korean Ceramic Society
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• v.28 no.6
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• pp.488-494
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• 1991

In this study, the effects of catalyst and DCCA content were investigated in order to determine the optimum conditions of monolithic silica gel formation through sol-gel process. Formamide, oxalic acid, glycerol and dimethylformamide are used as DCCA. To observe the phenomena in drying and heat-treating of gels, we examined structural exchange of gels using FT-IR, TG-DTA and XRD. Monolithic gels were obtained by adding formamide and dimethylformamide as DCCA. According to the heat treatment schedule, silica glass is prepared by heat-treatment up to 1050$^{\circ}C$.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.1
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• pp.22-29
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• 2002

The coated paper was greatly affected by the basic physical properties of the binder as well as the amount of the coating formula. High glass transition temperature (Tg) of the styrene-butadiene (SB) latex, selected as the binder in our study, gave the high stiffness to the coated paper, but lowered the binding force and print gloss. The average particle size of the SB latex also greatly affected to the coated paper so that the smaller particle size improved the rheological property of the coating formula and increased the binding force and print gloss. Another property of the SBR latex, gel content, was important because when its value was small, the latex was easily deformed at the high temperature and increased air permeability to the coated paper. Therefore, the lower gel content consequently resulted in the higher blistering resistance, especially in the web paper. The larger portion of the SB latex in the coated formula improved the binding force and print gloss, but decreased the ink set-off and ink-trapping to the coated paper. The heavier coating improved optical properties such as opacity, paper gloss and paper smoothness, to the coated paper.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1217-1220
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• 2005

Random amplified polymorphic DNA (RAPD-PCR) analysis of 56 animals of four different genetic groups of dwarf cattle in Kerala was done as a single step analysis. Bandsharing (BS) values were calculated for animals of each group and between groups as an analytical tool to find out genetic variation among animals. The different factors affecting BS values were estimated using Harvey''s Least squares analysis. The effects of genetic group, Guanine-cytosine (GC) content of primer and gel on BS values were found significant. Bandsharing values of Kasargode-Highrange dwarf animals were significantly different from Vechur, Vatakara and their combinations. The Vechur, Vatakara and Vechur-Vatakara combinations were found to be more uniform (high BS value) compared with other combinations. The bandsharing value was lowest with primers of GC content 90% and highest with 80% GC content. The effect of gel on BS value points to the need of adjustments of gel factor for calculation of BS values.

• Journal of Magnetics
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• v.20 no.3
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• pp.246-251
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• 2015

This study was aimed to study the effect of Zn content on the hyperfine parameters and the structural variation of $Ni_{1-x}Zn_xFe_2O_4$ for x = 0, 0.2, 0.4, 0.6, and 0.8. To achieve this, a sol-gel route was used for the preparation of samples and the obtained ferrites were investigated by X-ray diffraction, scanning electron microscopy, and $M{\ddot{o}}ssbauer$ spectroscopy. The formation of spinel phase without any impurity peak was identified by X-ray diffraction of all the samples. Moreover, the estimated crystallite size by X-ray line broadening indicates a decrease with increasing Zn content. This result was in agreement with the scanning electron microscopy result, indicating the reduction in grain growth with further zinc substitution. The room-temperature $M{\ddot{o}}ssbauer$ spectra show that the hyperfine fields at both the A and B sites decreased with increasing Zn content; however, the rate of reduction is not the same for different sites. Moreover, the best fit parameter showed that the quadrupole splitting values of B site increased from the pure nickel ferrite to the sample with x = 0.8.

• Polymer(Korea)
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• v.26 no.4
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• pp.508-515
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• 2002

The effects of the crosslinking caused by irradiation dose, molecular weights of the foaming materials, and various foaming processes on the foam structure of the polypropylene (PP) were investigated. The maximum gel content of the PP was 48% when the sheet was irradiated with 3.2 Mrad. This high gel content improved the cell structures by providing high thermal stability. The increase of both the gel content and structural development were stopped at the irradiation dose exceeding 3.2 Mrad. The increase of the molecular weights served to help produce a foam with particularly fine and even cell structures, along with improved thermal stability as well.