• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.50-54
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• 1999

Plasma display panel is a potential candidate for HDTV, due to the fact that the screen size can easily be increased by a thick film technology. In this study, transparent dielectric materials which satisfied the requirements of dielectrics for PDP was developed using lead alumina borosilicate glasses. The Paste which had thixotropic behavior suitable for screen printing was made of this glass composition. the paste became more thixotropic as the particle size decreased. After firing, the cross sectional area of the thick film was analyzed by SEM. The voids in the thick film were removed using bimodal particle system. The dielectric thick film showed good adhesion characteristics.

• Elastomers and Composites
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• v.49 no.2
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• pp.160-166
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• 2014

The formulation of six basecoats was designed using aluminium pastes for the per-painted system in the automotive. The aluminium pastes contain pancake type metallic pigment, #501, #801, #601 and cornflake type metallic pigment, #750, #770, #790. The relative cure density of the basecoat increased in order of #501, #801, #601, #750, #770, #790. T-bending, impact resistance, and taping adhesion showed increment with increasing cure density. In the appearance( combined factor) test on cornflake type pigment, The basecoat including the smallest particle size pigment, #790 resulted in the best combined factor compared to other two systems(#750, #770).

• Elastomers and Composites
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• v.51 no.2
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• pp.113-121
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• 2016

Magneto-rheological elastomer (MRE) is a material which shows reversible and various modulus under magnetic field. Comparing to conventional rubber vibration isolator, MREs are able to absorb broader frequency range of vibration. These characteristic phenomena result from the orientation of magnetic particle (i.e., chain-like formation) in rubber matrix. In this study, silicone rubber was used as a matrix of MREs. Carbonyl iron particle (CIP) was used to give magnetic field reactive modulus of MRE. The surface of the CIP was modified with chemical reactants such as silane coupling agent and poly(glycidyl methacrylate), to improve interfacial adhesion between matrix and CIP. The mechanical properties of MREs were measured without the application of magnetic field. The results showed that the tensile strength was decreased while the hardness was increased with the addition of CIP. Also, surface modification of CIP resulted in the improvement of physical properties of MRE, but the degree of orientation of CIP became decreased. The analysis of MR effect was carried out using electromagnetic equipment with various magnetic flux. As the addition of CIP and magnetic flux increased, increment of MR effect was observed. Even though the surface modification of CIP gave positive effect on the mechanical properties of MRE, MR effect was decreased with the surface modification of CIP due to decrease of CIP orientation. Throughout this study, it was found that the loading amounts of CIP affected the mechanical properties of MRE, and surface property of CIP was an important factor on MR effect of MRE.

• Journal of the Korean institute of surface engineering
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• v.46 no.5
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• pp.216-222
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• 2013

In order to improve the performance of electrodeposited diamond-nickel composite, surface modification of diamond particles was carried out using powder immersion reaction assisted coating (PIRAC). Titanium and chromium were selected as coating elements, which are known as carbide former. With respect to the powder elements, various phases were formed on diamond; metallic Ti and TiC for Ti powder, $Cr_3C_2$ for Cr powder, and TiC and $Cr_3C_2$ for Ti-Cr mixed powder. Surface modified diamond particle showed higher specific surface area, especially Ti coating induced considerable increase of specific surface area. The increase of specific surface area suggests increase of surface roughness, and that was confirmed by surface observation using FE-SEM. In addition, wear properties of diamond-nickel composite including surface modified diamonds were improved, and Ti coated diamond showed the highest performance. The wear property of diamond-nickel composite is dependent on adhesion strength between diamond particle and nickel layer. Therefore, surface modification of diamond particle by PIRAC increasing surface roughness is effective to improve the properties of diamond-nickel composite.

• Journal of the Korean Wood Science and Technology
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• v.34 no.4
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• pp.22-30
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• 2006

The volatile organic compound (VOC) Analyzer is a portable device to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styrene. With the VOC Analyzer, a semiconductor gas sensor eliminates the need for the carrier gas which is required for conventional gas chromatographs. In addition, since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. Compared with other measurement methods, the VOC analyzer is useful for measuring toluene, ethylbenzene, xylene and styrene in wood-based panel because of its ease in obtaining field results and repeating the test. The VOC Analyzer primarily measures four VOC in the air. In this study, we designed a test method of VOC measurement for particle board. A specimen was sealed in 3L polyester bag, after 96hours we could measure maximum VOC emission level that is a stabilized VOC Value. For easy, fast and economic testing of TVOC emission from wood-based panel, we developed the test method with the VOC Analyzer. The VOC Analyzer is expected to gain widespread use in the manufacturing field where a quick and easy test for VOC emission from wood-based panel is required. Furthermore, the VOC Analyzer promises to become an easier, faster and more economic technique than the currently used standard methods.

• Journal of the Korean Wood Science and Technology
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• v.33 no.6 s.134
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• pp.55-62
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• 2005

This study was conducted to evaluate the application of a bio-composite made by the addition recycled fiber board flour as filler. Recycled fiber board (high density fiber board, HDF) flour was added to polyolefin polymer low density polyethylene (LDPE) and polypropylene (PP) for the preparation of bio-composite materials. The mechanical properties and processability of the recycled HDF flour filled LDPE and recycled HDF flour filled PP bio-composites were then measured and compared to those of wood flour (WF) and rice-husk flour (RHF) filled LDPE and PP bio-composites, respectively. The tensile and impact strengths of the recycled HDF flour filled LDPE and PP bio-composites had similar mechanical properties to those of the WF and RHF filled LDPE and PP bio-composites. To measure the processability, torques of the bio-composites were also measured. The torques of the HDF flour filled LDPE and PP bio-composites were lower than those of the WF and RHF filled polyolefin (PP and LDPE) bio-composites with a filler loading of 30 wt.%. This result showed definite processability, which was not related with the distribution of the particle size of the material added. The recycled fiber board flour filled bio-composites showed applicability as substitutes for the bio-composites currently used in the bio-composites industry.

• Korean Journal of Computational Design and Engineering
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• v.20 no.3
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• pp.230-237
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• 2015

Soil deformation on the off-load ground is significantly affected by soil conditions, such as soil type, water content, and etc. Thus, the soil characteristics should be estimated for predicting vehicle movements on the off-load conditions. The plate-sinkage test, a widely-used experimental test for predicting the wheel-soil interaction, provides the soil characteristic parameters from the relationship between soil stress and plate sinkage. In this study, soil stress under the plate-sinkage situation is calculated by the DEM (Discrete Element Method) model. We developed a virtual soil bin with DEM to obtain the vertical reaction forces under the plate pressing the soil surface. Also parametric studies to investigate effects of DEM model parameters, such as, particle density, Young's modulus, dynamic friction, rolling friction, and adhesion, on the characteristic soil parameters were performed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.366-369
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• 2003

High T$_{c}$ superconducting lines will be applied as key materials in the areas of power transmission line; magnetic levitation of vehicle; magnetic separation; magnetic energy storage and marine propulsion. A combination method of electrophoresis deposition and zone-melting for preparation of YBaCuO tape is proposed. The submicron particle powder of YBaCuO made by sol-gel method is used in the electrophoresis process. A 40~50${\mu}{\textrm}{m}$ thickness of YBaCuO film on Ag plate could be deposited in about three minutes. After deposition the film is rolled and heat treated in order to increase the density and the adhesion of the film to the Ag plate. Silver(Ag) and lead oxide(PbO) were added in the YBaCuO powder in order to reduce its melting point. The YBaCuO coating with controlled Ag and PbO contents was preliminarily zone-melted at about 945$^{\circ}C$.>.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.12
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• pp.1253-1258
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• 2013

Ceramic particles as polishing abrasives are often used in a magnetic abrasive polishing process because they have strong wear resistance. Non-ferromagnetic ceramic abrasives should be mixed with ferromagnetic iron particles for controlling the mixture within a magnetic brush during the polishing process. This study describes the application of the ceramic particles for the magnetic abrasive polishing. The distribution of the magnetic abrasives attached on a tool varies with magnetic flux density and tool rotational speed. From the correlation between abrasive adhesion ratio in the tool and surface roughness produced on a workpiece, practical polishing conditions can be determined. A step-over for polishing a large sized workpiece is able to be selected by a S curve, and an ultrasonic vibration assisted MAP produces a better surface roughness and increases a polishing efficiency.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.339-344
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• 1997

During recent years the durability of concrete structures has attracted considerable interest in concrete practice, material research and long-term deformation. To preserve the brittleness of concrete as well as energy absorption and impact resistance, amount of fiber usage has greatly increased year to year in the field of public works. When fly ash, fine powder, mixed into concrete, it condensed the void of concrete structure. Expecially, there's a great effect for strength improvement of concrete by initial pozzolanic reactions. Pozzolan reaction, between cement particle and fly ash, can elaborate the micro structure of matrix. So it was able to improve the effect of fiber reinforced by increased adhesion between cement paste and steel fiber. And so, in this paper, we dealt SFRC for the purpose of efficiently using of industrial by-products and its economical manufacturing. Also we performed the test for durability such as chemical resistance, freeze-thaw resistance and accelerated carbonation of SFRC using fly ash.