• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.232-233
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• 2006

In recent years the interest in organic/inorganic hybrid materials has increased at a fast rate. Nano organic-inorganic hybrid composites have shown advantages for preparing hard coating layers. Especially, nano hybrid composite has low environmental pollution. It has high transparency, hardness, toughness, thermal dissociation temperature, hydrophobicity by using nano sized inorganic material. There are many ways in which these materials may be synthesized, a typical one being the use of silica and silanes using the sol-gel process. The structure of sol-gel silica evolves as a result of these successive hydrolysis and condensation reactions and the subsequent drying and curing. The sol-gel reactions are catalyzed by acids and produce silica sol solutions. The silica sol grows until they reach a size where a gel transition occurs and a solid-like gel is formed. Colloidal silica(CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. From all sol-gel solutions, seasoning effect of sol-gel coating layer on glass was observed.

• Elastomers and Composites
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• v.54 no.3
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• pp.247-251
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• 2019

Two different urethane acrylates (mono-acrylate and di-acrylate) were used to prepare unsaturated polyester-based hybrid gel-coats. The physical properties and surface characteristics of these gel-coats were investigated on the basis of the content and type of urethane acrylate. The set-to-touch time increased and the physical properties (surface hardness and tensile strength) decreased with an increase in the urethane acrylate content. However, the type of urethane acrylate did not affect these parameters. It was found that the optimal urethane acrylate content for the application of unsaturated polyester-based hybrid gel-coats is ~10 wt%.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.79-85
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• 1997

In order to improve the surface characteristics of polymethylmethacrylate(PMMA), oxide thin film coatings were applied using the sol-gel dip-coating technique. The $Si(OC_2H_5)_4$, tetra-ethyl-ortho-silicate(TEOS) was used as a starting material for $SiO_2$ coating. The hardness of the alkoxy-derived oxide-coated PMMA was increased from 190 MPa for non-coated PMMA with increasing film thickness. By optimizing the heating conditions and the hydrolysis conditions, a maximum apparent hardness obtained In the present study was achieved 310 MPa using the withdrawal velocity of 5cm/min and heat treatment at $90^{\circ}C$ for 5 hours, which is about 1.6 times larger than that of uncoated PMMA.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.465-470
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• 2006

Coating are needed on ophthalmic lenses to enhance both the mechanical durability of the relatively soft plastic surface and the optical performance of lenses. Organic-inorganic hybrid materials as molar ratio of 3-glycidoxypropyltrimethoxysilane(GPTS), methyltrimethoxysilane(MTMS) and tetraethyl orthosilicate(TEOS) were used to improve the surface characteristics and the optical properties on allyl diglycol carbonate lenses. Coating for these plastics were at $140^{\circ}C$ for 4hrs, applied using the sol-grl process flow-coating technique. The coated lens properties of transmittance, adhesion, pencil hardness, abrasion resistance, hot water resistance and chemical resistance were investigated. The optimum properties was obtained when the ratio of GPTS : MTMS : TEOS was 1:1:2, respectively.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.2
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• pp.145-150
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• 2014

This study investigates the preparation of anti-reflective (AR) coating film to improve the efficiency of solar cell. The AR coating film was successfully obtained by dip-coating with AR coatings prepared by sol-gel method. Fluoroalkylsilane was additionally introduced into the coatings to give the self-cleaning effect of AR coating film. We performed the abrasion test, pencil scratch hardness test and cross-cut test to identify the mechanical strength of AR coating film. As the results, the transmittance of AR coating films with 9.07, 18.13 and 27.20 of IPA/MTMS molar ratios were 93.1, 93.6 and 95.3%, respectively. The water contact angle and transmittance of AR coating film increased by the introduction of hydrophobicity. The prepared AR coating film shows the high level of abrasion, hardness and adhesion. The IPA/MTMS molar ratio of 27.20 and the withdrawing speed range of 0.20 ~ 0.28cm/sec are the optimal coating condition in terms of the transmittance and mechanical strength of AR coating film.

• Journal of the Korean Applied Science and Technology
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• v.38 no.6
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• pp.1561-1567
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• 2021

In this study, we have studied synthesis of zirconia-alumina composite coating materials via a low-temperature sol-gel process. The zirconia-alumina composites were prepared by coating zirconia precursor, alumina precursor, and organosilane mixture on a polyethylene terephthalate substrate through three steps: sol-gel process, low-temperature photocuring process, and heat treatment process. The structural properties and element analysis of the composites were confirmed by FT-IR and XPS. The coated composite showed a transmittance of 96% or more in the visible light region with a wavelength of 420 nm or more and pencil hardness of 9H or more. In case of the composite of the molar ratio of zirconia and alumina of 1:4, the highest nanoindentation hardness was measured with 1.212 GPa.

• Journal of the Korean Home Economics Association
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• v.19 no.4
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• pp.33-39
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• 1981

This study was attempted to determine the pectin contents of various fruits(Cherry, strawberry, plum, peach, apricot, apple, crabapple) and to investigate the changes in the properties of pectin and pectin gel during crabapple ripening. Methoxyl content, molecular weight and intrinsic viscosity were measured in ripened and unripened crabapples. In order to determine the characteristics of pectin gel, percent sag was measured by exchange Ridgelimeter, hardness and textural characteristics of jellies were measured by a penetrometer and a texturometer. The experimental results are summarized as follows: 1. The pectin contents of various fruits were 1.16% for cherry, 3.17% fir strawberry, 4.29% for plum, 5.51% for apricot, and pectin contents of peaches and apples varies depends on varieties from 4.54% to 5.61% to 6.52, respectively. The pectin contents of unripened and ripened crabapple wee 9.21% and 9.84% respectively, indicating that pectin content increased with fruit maturity. 2. The methoxyl contents, which was 6.61%~6.95%, was very low and it increased significantly during fruit ripening. Further, a decrease in acetyl content, intrinsic viscosity, molecular weight occurred during the ripening of crabapples. 3. The percent sag of crabapple jellies increased with fruit maturity from 5.26% to 5.79%, and the corresponding jelly grade decreased in ripened crabapple. 4. The hardness of jellies determined by a penetrometer was 79.15 pp.U. for ripened crabapple jelly, 90.62 pp.U. for unripe ned crabapple jelly. 5. In the textural characteristics of gels measured by a texturometer, the gels made from unripened crabapple were shown to have the highest values in hardness, cohesiveness, adhesiveness and gumminess.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.2
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• pp.109-115
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• 2009

The properties of surimi gel from Olive flounder Paralichthys olivaceus were evaluated with addition of various food additives and by heating under different conditions. The optimum heating conditions for get good textured surimi gel from Olive flounder was 40 minutes at $85^{\circ}C$. Optimum texture characteristics such as hardness, cohesiveness, chewiness, gumminess and gel strength of olive flounder fish paste can be acquired by washing the paste 2 times and by adding sodium chloride (2.5%), sodium polyphosphate (0.3%) and starch (4%), respectively. Furthermore, we compared gel texture characteristics and strength of manufactured Olive flounder fish surimi with commercial Alaska pollack to determine their commercial applicability. Texture characteristics and gel strength of Olive flounder surimi were higher than those of the commercial Alaska pollack surimi. In addition, both lightness and whiteness were higher in surimi gel from Olive flounder than from the commercial Alaska pollack.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.113-119
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• 2002

The effect of ultrasonic radiation is reported for silica-poly(ethylene glycol) system prepared without the solvent using sol-gel processing by varying various parameters such as ultrasonic irradiation time, PEG content and HCl/TEOS molar ratio. The property of sonogel is compared with classic gel which has been prepared with ethanol as a solvent by traditional sol-gel processing. SEM, BET, DTA-TGA, density and Vickers hardness measurements are carried out for analyzing the samples. The gelation time is found strongly dependent on radiation time, PEG content and pH value, and has been discussed on the basis of existing theories. The $SiO_2-10$ & 20 wt% PEG sonogel exhibited superior optical, physical and gel properties as compared to the classic gel, hence, found suitable for device applications. The ultrasonic radiation increased the density and surface area, and also reduced the pore size which is well supported by the shift in the peak of DTA curve. The DTA thermogram was found similar to that of pure silica gel.

• The Korean Journal of Food And Nutrition
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• v.21 no.2
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• pp.184-189
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• 2008

Soybean powder is a readily available ingredient that is consumed daily as a functional food material. Furthermore, red Ginseng is an herb with various physiological effects. Therefore, in this study, we examined the physiochemical characteristics of Soybean Dasik samples prepared with different amounts of added red Ginseng gel, including Hunter's color values, mechanical characteristics, and sensory qualities. The results of each analysis are as follows. For the soybean Dasik stored at room temperature($20^{\circ}C$), luminance was reduced as the amount of added red Ginseng gel increased. In addition, Hunter's a and b values were significantly higher in Dasik samples that did not contain red Ginseng gel, as compared to those with increasing red Ginseng gel content. The mechanical properties of the Dasik were also measured at room temperature showing significant differences between samples(p<0.001) for hardness, springiness, cohesiveness, gumminess, and chewiness. In the sensory evaluation, 3 rounds of testing indicated that sweetness acceptance scores were significantly reduced(p<0.001) as the amount of added red Ginseng gel in the Dasik increased. Finally, overall quality was significantly different between the samples(p<0.001) and acceptance scores increased with increasing red Ginseng gel content.