• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.55-59
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• 1999

The Rapid Expansion of Supercritical fluid Solutions (RESS) process was applied to particles coating. Microcapsules prepared by spray drying were used as the core particles, and two kinds of paraffin were used as the coating materials. Supercritical $CO_{2}$ solutions of paraffin were expanded through the short nozzle into the bed that was fluidized by air. Extraction temperature and pressure were varied at $50~120^{\circ}C$, $150~200\;kg/\textrm{cm}^2$, respectively. The thickness of theoritical coating layer ws measured, and precipitate coating layer on surface was analyzed by using SEM, FT-IR. The release behaviors of $Mg^{2+}$ ions were inspected by atomic absorbance spectrophtometer.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.684-687
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• 2004

We have developed multi-layer passivation films of UV-polymerized film/inorganic composite film to improve the long lifetime of passivated OLEDs for very thin flat panel applications. Preliminary lifetime to half initial luminance ($L_{o}{\sim}\;3,000\;cd/m^2$) of order 300 Hr is achieved on the conventional encapsulated test pixel using a passive matrix drive at room temperature; 570 Hr lifetime is achieved on a de tested multi-layer passivated 9$mm^2$ test pixel.

• The Journal of Korean Academy of Prosthodontics
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• v.38 no.3
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• pp.366-374
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• 2000

FRC/ceromer system provides the clinician with a durable, flexible, and esthetic alternative to conventional porcelain fused to metal crowns. FRC is the matrix which is silica-coated and embedded in a resin matrix. The ceromer material which is a second generation indirect composite resin contains silanized, microhybrid inorganic fillers embedded in a light-curing organic matrix. FRC/ceromer restoration has a several advantages: better shock absorption, less wear of occluding teeth, translucency, color stability, bonding ability to dental hard tissues, and resiliency. It has versatility of use including inlay, onlay, single crown, and esthetic veneers. With adhesive technique, it can be used for single tooth replacement in forms of inlay adhesion bridge. In single tooth missing case, conventional PFM bridge has been used for esthetic restoration. However, this restoration has several disadvantages such as high cost, potential framework distortion during fabrication, and difficulty in repairing fractures. Inlay adhesion bridge with FRC/ceromer would be a good alternative treatment plan. This article describes a cases restored with Targis/Vectris inlay adhesion bridge. Tooth preparation guide, fabrication procedure, and cementation procedure of this system will be dealt. The strength/weakness of this restoration will be mentioned, also. If it has been used appropriately in carefully selected case, it can satisfy not only dentist's demand of sparing dental hard tissue but also patient's desire of seeking a esthetic restorations with a natural appearance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.11
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• pp.961-968
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• 2009

In this work, transparent conductive oxide(TCO) films such as $In_2O_3-SnO_2$(ITO) and $In_2O_3-ZnO$(IZO) were prepared on polyethylene naphthalene(PEN) and glass substrates by using rf-magnetron sputtering system. The TCO films deposited on PEN substrate show very poor conductivity as compared to that of the TCO films deposited on glass substrates. From the results of the residual gas analysis(RGA) test, this poor stability of plastic substrate is presumed to be caused by the deteriorated adhesion between the TCO films and the plastic substrate due to outgassing from the plastic substrate during deposition of TCO films. From our experiment, it is found that the vaporization of some defects in the plastic substrates deteriorate the adhesion of the TCO films to the plastic substrate, because the most plastic substrates containing the water vapor and/or other adsorbed particles such as organic solvents. Mixing of these gases vaporized in the sputtering process will also affect the electrical property of the deposited TCO films. Inorganic thin composite $(SiO_2)_{40}(ZnO)_{60}$ film as a gas barrier layer is coated on the PEN substrate to protecting the diffusion of vapors from the substrate, so that the TCO films with an improved quality can be obtained.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.7 no.6
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• pp.42-50
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• 1993

In this paper the affect an inorganic filler and a f i n g up water absorption in epoxy composite material was represented. The results are summarized as follows ; 1. In the case of Sample 1, Sample 2 and a fillng up water absorption, the frequency depenence of E,' shows the straight characteristic underl4O0C. 2. Between lOOHz and 3kHz, the frequency dependency of tan8 is dominated by the loss of a dipole relaxation than the conductive loss for movement of a career. The effect of water absorption, is increased as the frequency is d e creased.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.494-499
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• 2001

The effects of accelerated Ultraviolet (UV) radiation on High temperature vulcanized (HTV), Room temperature vulcanized (RTV) silicone rubber and two types of ethylene propylene diene terpolymer (EPDM) used for composite insulator were investigated by hydrophobicity class (HC), surface voltage decay after corona charging, SEM-ES, FTIR and XPS. The contact angle in two kinds of silicone rubber was scarcely change, but EPDM occurred to the loss of hydrophobicity followed by surface cracking and chalking. The surface voltage decay on UV-treated silicone rubber and EPDM showed a different decay trend with UV treatment. EDS and XPS analysis indicated that the oxygen content increased with UV treatment time in all samples. For silicone rubber, the oxidized groups of inorganic silica-like structure increased with UV treatment time. The oxidized carbon of C=O, O=C-O in EPDM increased. These oxidized surface for each material had different electrostatic characteristics, so deposited charges were expected to have different impacts on their surface hydrophobicity. The degradation mechanism based on our results was discussed.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.319-330
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• 2005

Over the past few decades, much effort has been made to improve the mechanical and biological performance of HA, in order to extend its range of applications. As a major inorganic component of human hard tissues, hydroxyapatite bioceramic is regarded as being one of the most biocompatible materials. Numerous in vitro and in vivo studies have confirmed its excellent bioactivity, osteoconductivity and bone forming ability. However, because of its poor mechanical properties, its use in hard tissue applications has been restricted to those areas in which it can be used in the form of small sized powders/granules or in the non-load bearing sites. A number of researchers have focused on improving the mechanical and biological performance of HA, as well as on the formulation of hybrid and composite systems in order to extend its range of applications. In this article, we reviewed our recent works on HA-based biomaterials; i) the strengthening of HA with ceramic oxides, ii) HA-based bioactive coatings on metallic implants, iii) HA-based porous scaffolds and iv) HA-polymer hybrids/composites.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.955-960
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• 2012

In this study, pure Polyurethane and commonly used flame retardants $Al(OH)_3$ and $Mg(OH)_2$, the add-in sample and Cloisite Na+, Cloisite 15A added sample of flammability and mechanical properties are compared. Sodium silicate and a mixture of polyurethane that the lightweight filler Vermiculite, Perlite addition of flame retardant and mechanical properties of the sample was confirmed. As a result, the flame retardant additive in the Vermiculite and Perlite in a flame-retardant grade sample except sample were identified. Tensile strength is degrade accord to the filler amount. But, Sodium silicate in the case of the sample add-in, other than confirmed that the sample strength increases.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.99-99
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• 2010

Polymer nanocomposite has been attracting much attention as a new insulation material, since homogeneous dispersion of nm-sized inorganic fillers can improve various properties significantly. In this paper, various kinds of epoxy based nanocomposites were made and AC breakdown strength of Nano-TiO2 and micro-silica filler mixture of epoxy based composites were studied by sphere to sphere electrode. Moreover, nano- and micro-filler combinations were adopted as an approach toward practical application of nanocomposite insulation materials. Nano-TiO2 particle size is about 10nm and composites ratio was resin (100) : hardener (82) : accelerator (1.5). AC breakdown test was performed at room temperature (25 [$^{\circ}C$], 80 [$^{\circ}C$] and 100 [$^{\circ}C$] in the vicinity of Tg (90[$^{\circ}C$]). And thermal conductivity were measured by ASTM-D5470.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.29-29
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• 2010

Engineering plastics have excellent electrical properties, mechanical strength and various characteristic which include chemical resistance, environmental resistance, weatherability at a wide temperature range. It has good characteristic(light weight, good productivity) as compare with epoxy or porcelain insulators. However, engineering plastics not suited to outdoor insulator because it isn't hydrophobic. Therefore, to over come these critical problems, we improve the surface insulation characteristics of engineering plastic by coating micro-, nano- size inorganic fillers added to RTV-SIR(Room temperature vulcanized-silicone rubber) at this plastic surface. The effect is analyzed through salt-fog test, tracking test. In conclusion, the engineering plastic coated RTV with micro-$Al_2O_3$20[phr], nano-Al(OH)3 1 ~ 3[phr] improved much better than the others.