• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.450-456
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• 2005

In this paper, the effect of adhesion properties of semiconductive-insulating interface layer of silicone rubber on electrical properties was investigated. The modifications produced on the silicone surface by oxygen plasma were accessed using ATR-FTIR, contact angle and Surface Roughness Tester. Adhesion was obtained from T-peel tests of semiconductive layer haying different treatment durations. In addition, ac breakdown test was carried out for elucidating the change of electrical property with duration of plasma treatment. From the results, the treatment in the oxygen plasma produced a noticeable increase in surface energy, which can be mainly ascribed to the creation of O-H and C=O. It is observed that adhesion performance was determined by surface energy and roughness level of silicone surface. It is found that at dielectric strength was increased with improving the adhesion between the semiconductive and insulating interface.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.77-84
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• 2017

PURPOSE. The aim of this study was to compare the surface roughness of zirconia when using Zircos E etching system (ZSAT), applying a nitric acid-hydrofluoric acid compound as a pretreatment agent, and also to compare the shear bonding strength according to different resin cements. MATERIALS AND METHODS. ZSAT, air abrasion, and tribochemical silicacoating were applied on prepared 120 zirconia specimens (10 mm in diameter, 7 mm in height) using CAD/CAM. Each 12 specimens with 4 different resin cements (Panavia F 2.0, Rely X Unicem, Superbond C&B, and Hot bond) were applied to test interfacial bond strength. The statistical analysis was performed using SAS 9.1 (SAS Institute Inc., Cary, NC, USA). The results are as follows: after application of the ZSAT on the zirconia specimens, surface roughness value after 2-hour etching was higher than those after 1- and 3-hour etching on SEM images. RESULTS. For Superbond C&B and Rely X Unicem, the specimens treated with ZSAT showed higher shear bond strength values than those treated with air abrasion and tribochemical silicacoating system. Regarding the failure mode of interface over cement and zirconia surface, Rely X Unicem and Hot bond showed cohesive failures and Panavia F 2.0 and Superbond C&B showed mixed failures. CONCLUSION. Zircos E etching system in zirconia restoration could increase its shear bond strength. However, its long term success rate and clinical application should be further evaluated.

• The Journal of Advanced Prosthodontics
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• v.5 no.3
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• pp.248-255
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• 2013

PURPOSE. This study compared the effect of three intraoral repair systems on the bond strength between composite resin and zirconia core. MATERIALS AND METHODS. Thirty zirconia specimens were divided into three groups according to the repair method: Group I-CoJet$^{TM}$ Repair System (3M ESPE) [chairside silica coating with $30{\mu}m$ $SiO_2$ + silanization + adhesive]; Group II-Ceramic Repair System (Ivoclar Vivadent) [etching with 37% phosphoric acid + Zirconia primer + adhesive]; Group III-Signum Zirconia Bond (Heraus) [Signum Zirconia Bond I + Signum Zirconia Bond II]. Composite resin was polymerized on each conditioned specimen. The shear bond strength was tested using a universal testing machine, and fracture sites were examined with FE-SEM. Surface morphology and wettability after surface treatments were examined additionally. The data of bond strengths were statistically analyzed with one-way ANOVA and Tamhane post hoc test (${\alpha}$=.05). RESULTS. Increased surface roughness and the highest wettability value were observed in the CoJet sand treated specimens. The specimens treated with 37% phosphoric acid and Signum Zirconia Bond I did not show any improvement of surface irregularity, and the lowest wettability value were found in 37% phosphoric acid treated specimens. There was no significant difference in the bond strengths between Group I ($7.80{\pm}0.76$ MPa) and III ($8.98{\pm}1.39$ MPa). Group II ($3.21{\pm}0.78$ MPa) showed a significant difference from other groups (P<.05). CONCLUSION. The use of Intraoral silica coating system and the application of Signum Zirconia Bond are effective for increasing the bond strength of composite resin to zirconia.

• Journal of Sensor Science and Technology
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• v.14 no.6
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• pp.423-429
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• 2005

In this paper, we proposed the fabrication process of the stable e-beam evaporation and the patterning of metals layer on the polydimethylsiloxane (PDMS) substrate. The metal layer was deposited under the various deposition rate, and its effect to the electrical and mechanical properties (e.g.: adhesion-strength of metal layer) was investigated. The influence of surface roughness to the adhesion-strength was also examined via the tape test. Here, we varied the roughness by changing the reactive ion etching (RIE) duration. The electrode patterning was performed through the conventional photolithography and chemical etching process after e-beam deposition of $200{\AA}$ Ti and $1000{\AA}$ Au. As a result, the adhesion strength of metal layer on the PDMS surface was greatly improved by the oxygen plasma treatment. The e-beam evaporation on the PDMS surface is known to create the wavy topography. Here, we found that such wavy patterns do not effect to the electrical and mechanical properties. In conclusion, the metal patterns with minimum $20{\mu}m$ line width was produced well via the our fabrication process, and its electrical conductance was almost similar to the that of metal patterns on the silicon or glass substrates.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.3
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• pp.237-242
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• 2001

Ti-6Al-4V alloy can be obtained the stability of organization and product treasure, the evaluation of the cutting ability and the mechanical characteristics after the heat treatment of annealing, solution and aging. The difficulty in machining titanium alloy is how treat the heat generated during the process. Because the heat conductivity of titanium alloy is regardfully low, the heat generated during grinding is accumulated in workpiece. and it causes the increasing of grinding wheel grits' wear and makes the ground surface rough. So, these characteristics in grinding of titanium alloy will change the mechanical properties of the titanium alloy. From this study. the mechanical characteristics of annealed one and solution and aging one treated Ti-6Al-4V alloy after grinding was concerned with checking out the bending strength and hardness. For the result, both of bending strength and hardness were increased at the burned area on the surface. Roughness value was remarkably high at the table speed of 10m/min.

• Magazine of the Korea Concrete Institute
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• v.6 no.4
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• pp.161-168
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• 1994

Half-P.C. slab system is the composite structural system which utilizes precast concrete for lower portion and cast in situ concrete for upper portion slab. When the composite slab using Half P.C. slab is deformed by flexural moment, horizontal shear happened at the interface between Half P.C. slab and topping concrete. To resist horizontal shear strength a scratch method has tried. To determine ultimate interface shear strength, shear stress, and shear coefficient, high and normal strength concrete are used for topping concrete. Major variables are compressive strength of topping concrete with or without shear reinforcement, quantitative roughness of the P.C. :surface and tie or untie of the stud with welded deformed wire fabric in the P.C. member. The Icross sectional area on joints is 3,200 $cm^2$ in all specimens. Test results showed that shear stress increased, as the depth of the quantitative roughness increased. The horizontal shear strength could be resisted with safe by the quantitative roughness without shear tie. A shear coefficient determinant equation is proposed such that K = 0.025918 + 0.0068894$\cdot$R – 0.000182354${\cdot}R^2$

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.930-933
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• 2001

Titanium Alloys used in this experiment has an good corrosion resistance and specific strength, and is the new material developed for medical supplies living goods. In this study the rolled titanium alloy is done by annealing, solution heat-treatment and aging and then is worked by wire EDM. With changing the process conditions, the process properties of surface hardness, surface roughness, shape of process surface and the analysis of ingredients are measured through experiment repeating main cut and finish cut. It is confirmed to gain good measure values as increasing the number of processing of wire EDM. In this experiment the phenomena of processing is studied and the appropriate process condition is proposed.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.529-535
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• 2009

One of the most important things in shipbuilding is to select light and high tensile strength materials. Therefore, the use of Al alloy in shipbuilding become an increase. In cutting the aluminum plate, the quality of the cut surface is strongly influenced by the cutting conditions such as cutting speed, kerf width, plate thickness, cutting materials, and applied gas pressure. The cutting experiment of Al alloy plate(5083) were carried out using LASER cutting machine. The upper and lower of kerf width, the surface roughness(Ra, Rmax) of cut surface were measured under various cutting conditions. The morphologies of cutting surface were also monitored at various cutting conditions. The optimum cutting conditions of Al alloy among tested were indicated.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.128-133
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• 2010

The Titanium has many superior characteristics which are specific strength, heat resistance, corrosion resistance, organism compatibility, non-magnetic and etc. and their quantity are abundant. this study performed turning operation of Ti-6Al-4V alloy using the TiAlN Coated Tool which treated Physical Vapor Deposition. Experimental works are also executed to measure cutting force, tool wear, chip figuration and surface roughness for different cutting conditions. As a result of study. Cutting depth influences on the cutting force much more than the feed rate and the value of the cutting force is the most stable at the depth of 1.0mm. And tool wear was serious at over 100m/min of cutting speed and cutting condition was excellent at 1.0mm of cutting depth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1101-1104
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• 2001

The special purposed materials, such as ceramics and stainless steel, are widely used in the various industrial area. They have properties of the higher strength of material, the wear-resistance, and the corrosion proof. But ceramics is a difficult-to-grind material which possesses the higher level of a strength and a brittleness. In this study, the theoretical investigation of a grinding force and of a surface roughness was conducted. The evaluations of grinding characteristics on the hardened-brittle and difficult-to-grind materials were experimentally carried out.