• Journal of the Korean Geosynthetics Society
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• v.21 no.3
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• pp.29-39
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• 2022

The engineering characteristics of synthetic polymer-silica sol, which has the effect of reducing leakage, was evaluate and compared with typical grouting material, the water glass-based SGR injection material in this study. The result of the laboratory tests on strength and durability about the synthetic polymer-silica sol showed more than twice as high as LW-based injection materials in uniaxial compressive strength, significantly lower values in shrinkage rate and permeability. The result of pH was less than 8.5 (the drinking water quality standard). As a result of the leaching test, the Na₂O elution amount of the synthetic polymer-silica sol was measured to be 3 to 4 times smaller than that of the water glass grout. These results be assumed that the synthetic polymer-silica sol has better durability and permeability than those of the typical water glass-based grout.

• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.112-115
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• 1985

3-Aminopropylsilated silica gel bound hemin, biliverdin, and bilirubin were synthesized by reacting 3-aminopropyl silated silica gel with hemin, biliverdin and bilirubin respectively. The aspects of binding of bilirubin to amino group of 3-aminopropylsilated silica gel were studied using the above synthetic silica immobilized hemin, biliverdin and bilirubin, and oxodipyrromethene.

• Textile Coloration and Finishing
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• v.30 no.4
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• pp.275-287
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• 2018

In recent years, research on the development of eco-friendly synthetic suede based on water-dispersed polyurethane resin and non-fluorine water repellent has been conducted. Synthetic suede has a problem that the fastness to dyeing is greatly lowered after the water-repellent processing at a high temperature of $160^{\circ}C$ because the polyester is dyed with a disperse dye. Therefore, in this study, silica was added to water-dispersed polyurethane resin to improve dye fastness. To distribute the $PUD-SiO_2$ mixture evenly in the water-dispersed polyurethane resin, sufficient stirring was done for a period of time. When the $PUD-SiO_2$ mixture(PUD 1-5%) is applied to the substrate, it is confirmed through SEM that the mixture is uniformly applied without particle condensation. The results showed that silica with a diameter of 4~12nm and BET of $200{\sim}380g/m^2$ had the ability to improve dispersibility and fastness.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.357-367
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• 1997

A fast process for producing pure silica glasses with the reproducibility of 100% by means of sintering of silica aerogels was optimized. The density of silica glasses synthesized by heat-treating upto 110$0^{\circ}C$ with the heating rate of 0.1$^{\circ}C$/min was 2.197 g/㎤. Synthetic silica glasses(5 mm thickness) exhibited the transmittance of 92% in the near IR range as well as they had the excellent mechanical properties such as flexural strength of 162 MPa and hardness of 778 kg/$\textrm{mm}^2$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.4
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• pp.128-135
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• 2022

The inside of a quartz glass crucible for semiconductor processing, called a transparent layer, is manufactured using synthetic silica powder. Bubbles existing in the transparent layer of the crucible cause a problem of reducing the quality of the crucible as well as the yield of the silicon ingot. Therefore, the main goal of the synthetic silica powder, which is the raw material of the transparent layer, is to minimize the bubble generation factor. For this purpose, in the case of synthetic silica powder, it is necessary to minimize silanol groups, carbon and pores. In this study, synthetic silica gel was prepared using the sol-gel method, and changes in carbon content and specific surface area were investigated according to calcination temperature and dwelled time in a two-stage calcination process. The first-stage calcination process was performed between 500℃ and 600℃ and the second-stage calcination process was performed between 1000℃ and 1100℃. The dwelled time was carried out from 10 minutes to a maximum of 12 hours. The carbon content of the powder calcined at 1000℃ for 1 hour was 0.0031 wt.%, and the specific surface area of the powder calcined at 1100℃ for 12 hours was 16.6 m²/g.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.662-665
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• 2011

Highly efficient, three-component condensation of aromatic aldehyde, malononitrile and 4-hydroxycoumarin promoted by neat silica gel at room temperature is described. The method offers an excellent alternative to the synthesis of 3,4-dihydropyrano[c]chromenes. The reactions are fast and clean, and the products are obtained with good yield and purity.

• Elastomers and Composites
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• v.33 no.3
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• pp.185-192
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• 1998

This study was investigated on the physical properties of synthetic rubber compounds containing silica and silane copuled silica. Surface area and pore volume of silane copuled silica appeared to be low compared with those of pure silica because silane coupling agent blocks the pore of silica surface during silanization reaction. Silica with large surface area and high structure showed the short scorch time$(t_5)$ and rapid cure rate. The silane coupled silica showed the shorter scorch time and more rapid cure rate than pure silica because of the of effect of sulfur in the silane coupling agent(Si 69), The high value of $N_2SA$ minus CTAB com-pared with surface area and structure of silica showed the high 300% modulus. Also, the surface area and structure of silica did not affected the amount of PICO loss that indicate the abrasion resistance but affected the amount of cut and chip loss.

• Magazine of the Korean Society of Agricultural Engineers
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• v.34 no.E
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• pp.60-69
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• 1992

The research significance of the paper is to identify the major properties of synthetic lightweight concrete that are affected by ASR expansion and to determine the extent and magnitude of the loss in these properties. Emphasis is also given to the use of non-destructive testing techniques ; Such as dynamic modulus of elasticity and ultrasonic pulse velocity, to examine whether these methods could be used to identify the initiation of expansion and the internal structural damage caused by ASR.

• Macromolecular Research
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• v.17 no.1
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• pp.37-43
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• 2009

To fabricate dental nanocomposites containing finely dispersed silica nanoparticles, nearly monodispersed silica nanoparticles smaller than 25 nm were synthesized without forming any aggregates via a modified sol-gel process. Since silica nanoparticles synthesized by the Stober method formed aggregates when the particle size is smaller than 25 nm, the synthetic method was modified by changing the reaction temperature and adding poly(1-vinyl-2-pyrrolidinone) (PVP) to the reaction mixture. The size of the formed silica nanoparticles was reduced by increasing the reaction temperature or adding PVP. Furthermore, the formation of aggregates with primary silica nanoparticles smaller than 25 nm was prevented by increasing the amount of PVP added to the reaction mixture. To enhance the dispersion of the silica particles in an organic matrix, the synthesized silica nanoparticles were treated with 3-methacryloxypropyltrimethoxysilane ($\gamma$-MPS). A dental nanocomposite containing finely dispersed silica nanoparticles could be produced by using the surface-treated silica nanoparticles.

• Journal of Powder Materials
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• v.12 no.2 s.49
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• pp.122-130
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• 2005

Layered silicate was synthesized at hydrothermal condition from silica adding to various materials. Nano-clay was synthesized by intercaltion of various amine compounds into synthetic layered silicate. The products were analysed by XRD, SEM, and FT-IR in order to examine the condition of synthesis and intercalation. From the results, it was confirmed that kaolinite was synthesized from precipitated silica and gibbsite at $220^{\circ}C$ during 10 days, and hetorite was synthesized from silica sol at $100^{\circ}C$ during 48 h. Na-Magadiite was synthesized from silica gel at $150^{\circ}C$ during 72 h, and Na-kenyaite was synthesized from silica gel at $160^{\circ}C$ during 84 h. Nano-clay was prepared using synthetic layered silicate intercalated with various amine compounds. Kenyaite was easily intercalated by various organic compounds, and has the highest basal-spacing value among other layered silicates. Basal-spacing was changed according to the length of alkyl chain of amine comopounds. Polymer can be easily intercalated by dispersion with large space of interlayer. Finally, epoxy/nano-clay nanocomposite can be easily prepared.