• Advances in materials Research
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• v.1 no.1
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• pp.93-107
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• 2012

Epoxy resin is widely used in high voltage apparatus as insulation. Fillers are often added to epoxy resin to enhance its mechanical, thermal and chemical properties. The addition of fillers can deteriorate electrical performance. With the new development in nanotechnology, it has been widely anticipated that the combination of nanoparticles with traditional resin systems may create nanocomposite materials with enhanced electrical, thermal and mechanical properties. In the present paper we have carried out a comparative study on dielectric properties, space charge and dielectric breakdown behavior of epoxy resin/nanocomposites with nano-fillers of $SiO_2$ and $Al_2O_3$. The epoxy resin (LY556), commonly used in power apparatus was used to investigate the dielectric behavior of epoxy resin/nanocomposites with different filler concentrations. The epoxy resin/nanocomposite thin film samples were prepared and tests were carried out to measure their dielectric permittivity and tan delta value in a frequency range of 1 Hz - 1 MHz. The space charge behaviors were also observed by using the pulse electroacoustic (PEA) technique. In addition, traditional epoxy resin/microcomposites were also prepared and tested and the test results were compared with those obtained from epoxy resin/nanocomposites.

• Journal of Technologic Dentistry
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• v.42 no.1
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• pp.27-33
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• 2020

Purpose: This study is to compare and analyze the precision of glass fiber resin dentures. Methods: A lower edentulous model was prepared. Ten study models were produced using Type IV stone. Ten wax lower resin dentures containing artificial teeth were prepared. The lower wax denture was buried with plaster and deflasking was performed to remove the wax. Five conventional lower resin dentures and five glass fiber lower resin dentures were produced. The scanning spray was coated on the impression surface and then scanned. Independent sample t-test were performed using statistical software. Results: In the color different map, which is a qualitative evaluation, the green area of the precision of the conventional lower resin denture occupied the whole. The glass fiber conventional resin dentures had many negative and positive area. In quantitative evaluation, the RMS of conventional lower resin was 89.83 ㎛ and that of fiberglass resin was 224.92 ㎛. The two groups showed statistically significant differences (p<0.05). Conclusion: Conventional lower resin dentures were superior in precision, and glass fiber resin dentures would have to improve the process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.878-881
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• 2005

A Stereolithography technology is based on stacking of sliced layer from STL file that is converted from 3-dimensional CAD data. A microstereolithography technology is evolved from conventional stereolithography to fabricate microstructures. In this technology, we have to consider influence of resin flow to make refresh surface. To generate new resin surface, stage has to be moved downward deeply and upward to desired position. At this time, resin flow affects to refresh surface of resin. And resin viscosity is the key factor in simulation of resin flow. By setting optimal refresh time for resin surface, total fabrication time is reduced and there is no damage to fabricated layers. In this research, we simulate resin flow using CFD software and derive optimal stage moving time and dwelling time.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.5 s.108
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• pp.78-84
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• 2004

Lignin precipitated from black liquor of soda pulping of bagasse was used to prepare cation-exchange resin. The effect of sulfuric acid treatment, concentration of phenol and formaldehyde on the properties of the prepared cation-exchange resin was investigated. It was found that sulfonated resinified phenolated lignin gave a resin with an ion-exchange capacity higher than that of resin, which resulted from sulfonation of resinified lignin at zero phenol concentration. Infrared spectroscopy of the prepared ion-exchange resin shows anew bands at 1060, 1160, 1280 and $1330\;cm^{-1}$ which indicated to the presence of $SO_{3}$.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.284-287
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• 2002

During resin transfer molding(RTM) process, in case of thick parts, resin flow and void formation should be modeled three dimensionally even though for parts of small thickness, resin flow and void formation can be modeled two dimensionally. In this study, numerical simulations of three dimensional mold filling and void formation during RTM process.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.257-260
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• 2000

The composite composed of glass fabric and BMI resin was fabricated using resin transfer molding(RTM) process. it will be used as a supporting plate of transformer coil for high speed train. To develop a RTM process, permeability of preform was measured and resin properties like a viscosity and gellation time were checked. A resin pre-heating system and a mold system were also designed and developed. Using a vacuum-assisted RTM process, the composite supporting plate was successfully fabricated.

• The Journal of the Korean dental association
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• v.53 no.3
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• pp.187-194
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• 2015

This paper reflects on the state of the art of two kinds of tooth hard tissue (enamel and dentin) bonding with resin cement. After presenting composition of resin cement, concepts of enamel bonding and resin bonding are addressed. Special attention is devoted to the concept and advantage of self-etching technique. Finally, recommended clinical performance regarding bonding to tooth with resin cement is summarized.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3413-3416
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• 2012

Phenol-free resin was synthesized and its printing ink properties were investigated. The phenol-free resin was produced by esterification of poly phthalate and Diels-Alder adduct of rosin anhydride. Compared to rosin modified phenolic resin, eco-friendly phenol-free resin showed better vehicle properties in terms of gloss, yellowing, runability, and storage stability. The results suggest the utility of phenol-free resin instead of conventional rosin modified phenolic resin.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.313-322
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• 2004

Glasses are to be classified in organic glasses and inorganic glasses. Generally, we just call glasses instead of calling inorganic glasses and call synthetic resin or plastic instead of calling organic glasses. One of the ophthalmic plastic glasses develops into polycarbonate resin in organic glasses. Recently, polycarbonate resin is widely known because it has larger index and impact than plastic lens. Ours study analyzed about polycarbonate resin in ophthalmic substance.

• Journal of the Korea Furniture Society
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• v.20 no.3
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• pp.247-252
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• 2009

The objective of this study was the dimensional stabilization of Korean red pine (Pinus densiflora) wood by the water-based thermosetting resin. A commercial melamine-formaldehyde resin was impregnated into wood samples and cured. The weight and dimensional change of woods treated by the resin, and the absorption and dimensional behavior of treated woods were investigated. The melamine-formaldehyde resin treatment improved significantly the dimensional stability of pine wood and showed about 40% of antiswelling efficiency. The mechanism of dimensional stabilization was interpreted as the complicated reason, such as bulking effect by the resin in cell wall, mechanical restraint and/or blocking of hygroscopic site by the resin in lumen.