• Journal of Surface Science and Engineering
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• v.32 no.3
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• pp.428-432
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• 1999

As metallic surface has its unique lustrous appearance and optical reflectance in visible range of light, the metallization of plastic surface has been an essential drive toward weight reduction for fuel economy and decorations in transportation industry and has been put into practiced from wet chemical-electrochemial to dry vacuum process in view of an environmental effect. Electron-beam metallization was used in this work with an aim at improving the scratchproof surface hardness of plastic substrate with metallic finish character. Thin film of Al ($1000\AA$) and $SiO_2$($7000\AA$) were metallized on substrate of PC and PMMA and the films were evaluated by pencil test for surface hardness and by cross-cut tape test for adhesion. The ion beam treatment improved around twice as hard as non-treat surface. The ion beam is effect on its hardness and adhesion to surface hardened PC substrate.

• Fashion & Textile Research Journal
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• v.22 no.5
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• pp.628-638
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• 2020

This study develops a cool-touch functional Dancesport top for middle-aged women by using cool-touch materials in areas where surface temperature becomes high after exercise. The post-exercise surface temperature of the developed research product was compared and analyzed. In addition, subjective evaluation of cool-touch as well as appearance and movement evaluations were performed. The results are as follows. In designing the research product, a detachable neckband was made using highly-preferred hydrated polymer crystals. A material with high moisture absorption speed was also used in F1, S1, under arm and B5, while a material with good thermal conductivity was used in other parts of the bodice. Deodorant tape with antibacterial and deodorant effects was incorporated in the armpit for additional comfort. As for wear evaluation of the research product, significant differences were found in 10 areas using a material with high moisture absorption speed to compare and analyze the post-exercise surface temperatures of the clothing. The temperature difference between the compared top and the research product in the neckband area was 9.16℃, demonstrating clear cool-touch function in using cool-touch material. In the subjective evaluation of cool-touch function, the results showed high scores when asked about the efficiency of the detachable neckband and the ease of movement when wearing the product. In the appearance evaluation, significant differences were found in 11 items, including redundant folds, tightfit, fit, and design line. The overall mean score of the movement evaluation was 4.6, indicating excellent function for movement.

• Elastomers and Composites
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• v.44 no.4
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• pp.358-365
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• 2009

High-frequency induction is an efficient way to rapidly heat mold surface by electromagnetic induction. In the present work, high-frequency induction heating is applied to injection molding of a mobile phone cover in order to eliminate weldlines by efficiently raising the mold temperature. Through the induction heating experiments, the maximum temperature of $143^{\circ}C$ is obtained on the mold surface in 3s of heating, which is higher than the glass transition temperature of the resin material. An injection molding experiment is then performed with the aid of induction heating, from which we can successfully remove all the weldlines of the mobile phone cover. The effect of induction heating conditions such as the heating power and the heating time on the surface appearance is experimentally investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.636-636
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• 2013

Since first discovery of strong Raman spectrum of molecules adsorbed on rough noble metal, surface enhanced Raman scattering (SERS) has been widely used for detection of molecules with low concentration. Surface plasmons at noble metal can enhance Raman spectrum and using Au nanostructures as substrates of SERS has advantages due to it has chemical stability and biocompatibility. However, the photoluminescence (PL) background from Au remains a problem because of obtaining molecular vibration information. Recently, graphene, two-dimensional atomic layer of carbon atoms, is also well known as PL quenchers for electronic and vibrational excitation. In this study, we observed SERS of single layer graphene on or under monolayer of Au nanoparticles (NPs). Single layer graphene is grown by chemical vapor deposition and transferred onto or under the monolayer of Au NPs by using PMMA transfer method. Monolayer of Au NPs prepared using Langmuir-Blodgett method on or under graphene surface provides closed and well-packed monolayer of Au NPs. Scanning electron microscopy (SEM) and Raman spectroscopy (WItec, 532 nm) were performed in order to confirm effects of Au NPs on enhanced Raman spectrum. Highly enhanced Raman signal of graphene by Au NPs were observed due to many hot-spots at gap of closed well-packed Au NPs. The results showed that single layer graphene provides larger SERS effects compared to multilayer graphene and the enhancement of the G band was larger than that of 2D band. Moreover, we confirm the appearance of D band in this study that is not clear in normal Raman spectrum. In our study, D band appearance is ascribed to the SERS effect resulted from defects induced graphene on Au NPs. Monolayer film of Au NPs under the graphene provided more highly enhanced graphene Raman signal compared to that on the graphene. The Au NPs-graphene SERS substrate can be possibly applied to biochemical sensing applications requiring highly sensitive and selective assays.

• Journal of the Korean Wood Science and Technology
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• v.9 no.1
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• pp.1-12
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• 1981

The structure of spiral thickenings, particulary the appearance, arrangement and orientation of thickenings in compression wood of Torreya nucifera, were studied in detail by light and polarizing microscope, scanning and transmission electron microscope. The results obtained are as follows: (1) Using the inclined sections at an angle of 45 degrees to the fiber axis, it seems that we can not only observe the more accurate transverse view of the thickenings but also investigate the formation of their thickenings. (2) Generally 2-4 pieces of thickenings are projected to the cell lumen as nipple-like appearance in transverse section and are as frequent, well developed, forming pair and have the rope-like appearance in radial surface. (3) The secondary wall of early wood is composed of 3 layers (S1, S2, S3) and orientation of thickening appears S helix but that of late wood is of 2 layers (S1, S2) and that orientation shows Z helix. Above two regions are demaracted at several tracheid cells from the growth ring boundary. (4) Orientation of thickening seems to be a element showing the characteristics of compression wood in Torreya nucifera. (5) It believes that the thickenings of compression wood are integral part of the S3 in early wood tracheids and of the S2 in late wood and have the same orientations as the inner-most microfibrils in these layers. (6) Thickening and cavities seem to be not formed together in a secondary cell wall of same tracheids.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.24 no.1
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• pp.49-67
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• 2015

Since the implant became the important treatment modality in dentistry, the research and clinical effort to mimic natural tooth appearance have been pursued. While the rehabilitation of mastication and occlusal appearance was focused in the past, more esthetic and functional restoration was preferred recently. To fulfill this demand, the clinicians should consider the axial contour, papilla space, subgingival appearance, as well as the shape of occlusal surface. In the surgery part, there have been significant advances in the adequate formation of bone and soft tissue through the careful reflection on the surgery time and incision. When the dentist has good knowledge about this aspect and passion for the final product, he or she can acquire better results.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.148-148
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• 2017

Surface modification is a type of mechanical manipulation skills to achieve extensive aims including corrosion control, exterior appearance, abrasion resistance, electrical insulation and electrical conductivity of substrate materials by generating a protective surface using electrical, physical and chemical treatment on the surface of parts made from metallic materials. Such surface modification includes plating, anodizing, chemical conversion treatment, painting, lining, coating and surface hardening; this study conducted cavitation experiment to assess improvement of durability using anodizing. In order to observe surface characteristics with applied current density, the electrolyte temperature, concentration was maintained at constant condition. To prevent hindrance of stable growth of oxide layer due to local temperature increase during the experiment, stirring was maintained at constant speed. In addition, using galvanostatic method, it was maintained at processing time of 40minutes for 10 to $30mA/cm^2$. The cavitation experiment was carried out with an ultra sonic vibratory apparatus using piezo-electric effect with modified ASTM-G32. The peak-to-peak amplitude was $30{\mu}m$ and the distance between the horn tip and specimen was 1mm. The specimen after the experiment was cleaned in an ultrasonic bath, dried in a vacuum oven for more than 24 hours, and weighed with an electric balance. The surface damage morphology was observed with 3D analysis microscope. As a result of the study, differences were observed surface hardness and anti-cavitation characteristics depending on the development of oxide film with the anodizing process time.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.437-440
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• 2009

High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a non-contact manner. Thanks to its capability of rapid heating and cooling of mold surface, it has been recently applied to the injection molding. The present study applies the high-frequency induction heating for elimination of weldlines in an injection-molded plastic part. To eliminate weldlines, the mold temperature of the corresponding weld locations should be maintained higher than the glass transition temperature of the resin material. Through experiments, the maximum temperature of $143^{\circ}C$ is obtained on the mold surface around the elliptic coil, while the temperature of the mold plate is lower than $60^{\circ}C$. An injection molding experiment is then performed with the aid of induction heating, and the effect of induction heating conditions on the surface appearance of the weldline is investigated.

• Journal of Surface Science and Engineering
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• v.34 no.6
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• pp.537-544
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• 2001

In the present study, tin-zinc alloys were coated on a cold-rolled steel sheet with variations of electrolyte concentration, additives quantity and current density employing the Hull cell and circulation cell simulator. With an addition of additives of 2m1/L, tin-zinc deposits containing 10 to 40 percent Zn revealed a good surface appearance with weak acidic electrolytes. The organic additives suppressed the Sn deposition rate and thus increased the zinc contents in tin-zinc coating layers. The zinc contents in the tin-zinc coating layers depended almost linearly on the concentrations of metal ions of tin and zinc. Temperature of the electrolyte affected the composition tin-zinc coating layer. However, the concentration of complexants revealed little effectiveness. The surface morphology of tin-zinc coating showed dense tin and zinc phases with fine equiaxed grains with the high current density.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.71-76
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• 2003

This paper describes the characteristic of a large-diameter pipe to obtain smooth surface using Electropolishing after grinding using a non-woven fabric. Grinding using a non-woven fabric is possible under lower load and fine effect comparing with Wheel grinding. Also, the ion from the surface of the metal is eliminated by means of an electrical potential and current in Electropolishing. Electropolishing is used for leveling the surface, improving the physical appearance of the part, promoting corrosion properties and reducing contamination and adhesion of the surface. Therefore, the aim of the present study is to investigate the internal machining of a large-diameter pipe for semiconductor using experimental design method.