• Journal of Technologic Dentistry
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• v.37 no.4
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• pp.235-242
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• 2015

Purpose: The aims of this study are compare with microstructure and mechanical properties of Co-Cr-Mo alloys fabricated by powder metallurgy(P/M) process and casting process respectively. Methods: Microstructure and micro-hardness were tested by SEM and Vickers Hardness Tester. The sintered specimen was produced by furnace-coolling after sintering, however the casting specimen were produced thru air-cooling and water-cooling after the casting. For observation of phase transformation during sintering, DSC analyzing was carried out. Results: Mean pore size of sintered Co-Cr-Mo alloy was $4.32{\mu}m$ and that of casting alloy was $1.63{\mu}m$. Hardness of sintered alloy was lower than water-quenched casting alloy. Conclusion: Proper sintering temperature of Co-Cr-Mo alloy was above $1,200^{\circ}C$ and pore size of casting specimen were finer than sintered specimen, but hardness were similar.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.6
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• pp.962-971
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• 2004

This paper has dealt with thermo-physical properties of microencapsulated phase change material slurry as a latent heat storage material having a low melting point. The measured results of the thermo-physical properties of the test microencapsulated phase change material slurry, those are, density, specific heat, thermal conductivity and viscosity, were discussed for the temperature region of solid and liquid phases of the dispersion material (paraffin). The measurements of these properties of microencapsulated phase change material slurry have been carried out by using a specific-gravity meter, a water calorimeter, a differential scanning calorimeter(DSC), a transient hot wire method and rotating type viscometer, respectively. It was clarified that the additional properties law could be applied to the estimation of the density and specific heat of microencapsulated phase change material slurry and also the Euckens equation could be applied to the estimation of the thermal conductivity of this slurry.

• Textile Coloration and Finishing
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• v.22 no.2
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• pp.155-162
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• 2010

Nylon 6 was blended with a brominated epoxy resin, tetrabromobisphenol A diglycidyl ether (DGEBBA), to enhance flame retardant property. Thermal properties of the blends were analyzed by DSC. Melting point and crystallization temperature decreased as the amount of epoxy resin increased. Melt index and relative viscosity decreased as the amount of the epoxy resin increased. When the blended amount of the epoxy resin was below 5%, the melt index decreased while the relative viscosity slightly increased. The blend resin was successfully spun into fiber without swelling or drawing the resonance phenomena. However, both the tenacity and elongation of the fiber decreased by increasing the amount of the DGEBBA.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.990-992
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• 2011

In this paper, epoxy nanocomposites, focusing on the electrical properties of the composites to understand controllers, circuit breakers, bushings and power to apply to the modified instrument was carried out basic research. Composed of composites of this study to develop a power unit to control the dispersion synthesis technology is essential electrical appliances such as electrical properties analysis techniques will also need basic research skills and experience accumulated in this study, several areas of applied technology. In this study, promotion and application of nano-composite material application technology power devices than conventional insulation materials and excellent electrical properties and easy synthesis and high reliability are expected to be practical if you expect that its effects are very large. Therefore, this study has very importance.

• Journal of the Korean Graphic Arts Communication Society
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• v.14 no.1
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• pp.115-131
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• 1996

The PVT(pressure-volume-temperature) relation of main-chain dimer liquid crystals having structures such as $\alpha$,$\omega$-bis[(4,4`-cyanobiphenyl) oxy] alkane(CBA-n with=9, 10) were studied. these dimer liquid crystals are known to form an enantiotropic nematic mesophase. In this work, we have determined the volume change as a function of temperature and pressure by using a GNOMIX PVT apparatus. In the V-Tcurves obtaind from isobaris mearements on various pressures, volume changes were observed at the nematic-isotropiz and nematic-crystal phase transitions. The volume changes at the transition exhibit slight odd-even effect with respect to the number of methylene unit n. The values of the (S)v obtained at the NI transition for CBA-9 and -10 were 6.9 and 12.6J/mol k. The valuesof (S)v for the CN transition were estimated on the basis of DSC(differential scanning calorimetry) data: 58.8(CBA-9) and 65.3J/mol k (CBA-10). For both transition, it was found that the correction about the volume change is significant, ranging from 40% to 60% of the total transition entropy observed under constant pressure.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.430-436
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• 1990

Glasses of different compositions were synthesized by substituting each component of 56ZrF4-14BaF2-6LaF3-4AlF3-20NaF(ZBLAN) with HfH4, SrF2, GdF3, InF3 and LiF3, each of similar size and chemical property with the component being substituted, respectively. The heating rate used in the DSC runs was 10K/min. All ofthe glasses exhibit glass transition temperatures of 510$\pm$10K, while crystallization temperatures vary between 625 and 720K depending upon different glass compositions. For most glasses crystallization temperatures obtained while cooled are lower than those obtained while heated, but InF3 or SrF2 containing glasses showed opposite trend. HBLAN, ZHBLAN and ZHBLANLi glasses, which were made by substituting HfH4, LiF for ZrF4 and NaF of ZBLAN respectively, showed improvement in the glass stability.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.83-83
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• 2010

This study investigates the thermal and mechanical properties of insulation elements through mixing epoxy based micro- and nano particles. Regarding thermal properties, DSC and DMA were used to calculate crosslinking densities for various types of insulation elements. In a mechanical property of bending strength, shape and scale parameters were obtained using the Weibull plot. This study obtained the most excellent results of scale parameters, such as Vol 3.2%, in the bending strength of EMNCs.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.797-803
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• 2001

The on-line cure monitoring of fiber reinforced thermosetting resin matrix composite material was performed for the better quality and productivity during manufacturing. Since the dissipation factor measured by dielectrometry method is dependent on the degree of cure and temperature of resin, in this study, a new method to obtain the degree of cure during on-line cure monitoring for glass/polyester composites was developed by employing a combination function of the temperature and the dissipation factor. Two sensor signals from a K-type thermocouple and an interdigitated dielectric sensor were processed during curing process under various cure cycles. The DSC (Differential Scanning Calorimetry) data was also used for the reference of degree of cure.

• Journal of the Korean Wood Science and Technology
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• v.37 no.2
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• pp.155-163
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• 2009

This study examined the thermal stability of PLA-WF bio-composites. Wood flour (WF)-filled PLA bio-composites were reinforced with the flame retardants, Melamine pyrophosphate (MPP), resorcinol bis (diphenyl phosphate) (RDP) and zinc borate (ZB). The flame retardant was compounded with PLA and natural biodegradable filler. The thermal properties of the biodegradable polymer and bio-composites reinforced with the flame retardant were measured and analyzed by DSC, DMA and TGA. The results showed that the flame retardant-reinforced biodegradable bio-composite exhibited improved thermal properties.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.91-96
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• 2000

Glass fiber reinforced thermoplastic composites were manufactured by Rapid Press Consolidation Technique(RPCT) as functions of temperature, pressure and time in pre-heating, consolidation and solidification sections during the manufacturing processing. It was found that the material property is greatly affected by pre-heating temperature under vacuum, mold temperature and molding pressure. Among them, the temperature In the mold was the most critical factor in determining the mechanical properties and the molded conditions of specimen. The crystallinity of PET matrix was also investigated by differential scanning calorimetry(DSC) measurements for various processing conditions. The level of crystallinity($X_c$) depended strongly on the mold temperature, cooling rate and the type of composite. The difference in $X_c$ is believed to be one of important factors in characterizing the mechanical properties.