• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.104-109
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• 2017

PURPOSE. The purpose of this study was to evaluate the influence of acid etching treatment on surface characteristics and biological response of glass-infiltrated zirconia. MATERIALS AND METHODS. A hundred zirconia specimens were divided into four groups depending on surface treatments: untreated zirconia (group Z); acid-etched zirconia (group ZE); glass-infiltrated zirconia (group ZG); and glass-infiltrated and acid-etched zirconia (group ZGE). Surface roughness, surface topography, surface morphology, and Vickers hardness of specimens were evaluated. For biological response test, MC3T3-E1 cell attachment and proliferation on surface of the specimens were examined. The data were statistically analyzed using one-way ANOVA and Tukey's HSD test at a significance level of 0.05. RESULTS. Group ZGE showed the highest surface roughness ($Ra=1.54{\mu}m$) compared with other groups (P < .05). Meanwhile, the hardness of group Z was significantly higher than those of other groups (P < .05). Cell attachment and cell proliferation were significantly higher in group ZGE (P < .05). CONCLUSION. We concluded that effective surface roughness on zirconia could be made by acid etching treatment after glass infiltration. This surface showed significantly enhanced osteoblast cell response.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.1
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• pp.170-178
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• 2019

Recently, as the interest in energy savings has increased, there has been increasing use of LED lighting, which is an eco-friendly device that replaces high energy consuming fluorescent lamps and incandescent lamps. In the case of a high output LED, however, the life time is shortened due to deterioration caused by heat generation. As a solution to this problem, this paper evaluated the LED life extension effect by increasing the convective heat transfer coefficient of the heat sink surface for LED packaging. A roughing process was carried out using sandpaper and sand blasting. The changes in surface roughness and surface area after each surface treatment process were evaluated quantitatively and the convective heat transfer coefficient was measured. When sandblasting and sandpaper were used to roughen the aluminum surface, a higher convection heat transfer coefficient was obtained compared to the untreated case, and a high heat dissipation efficiency of 82.76% was obtained in the sandblast treatment. Therefore, it is expected that the application of heat dissipation to the heat sink will extend the lifetime of the LED significantly and economically by increasing the heat efficiency.

• Journal of Technologic Dentistry
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• v.45 no.2
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• pp.39-47
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• 2023

Purpose: This study aimed to confirm the applicability of gloss polishing using automatic barrel finishing with respect to three-dimensional (3D)-printed resin specimens. The surface roughness and grinding angle of the 3D-printed resin specimens were observed with respect to gloss polishing time using automatic dental barrel finishing. Methods: Herein, experiments were conducted on four types of 3D-printed resin specimens. The specimens, with a thickness of 100 ㎛ each, were printed using a 3D printer. Subsequently, light polymerization was performed on these specimens for 15 min. Post this surface treatment, the specimens underwent grinding for 25 min. This process was followed by gloss polishing at 5-min intervals for up to 25 min using automatic dental barrel finishing. The specimens were photographed using a 3D optical microscope, and their surface roughness and grinding angle were measured. Results: The Ra (centerline average roughness) values of all the specimens, except for crown & bridge 10 group and those in the control group that were not polished using automatic barrel finishing, were <0.2 ㎛. However, polishing time needs to be controlled to realize the desired surface roughness and grinding amount considering the hardness of the resin used. Conclusion: Gloss polishing of 3D-printed resin can be realized using automatic dental barrel finishing. However, polishing time needs to be controlled to realize the desired surface roughness and grinding amount considering the hardness of the resin used.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1998.05a
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• pp.54-55
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• 1998

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.2
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• pp.111-117
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• 2008

We have studied surface roughness, contamination of impurity, bonding with some gas element, reflectance and zeta potential on masks to be generated or changed during photolithography/dry or wet etching process. Mask surface roughness was not changed after photolithography/dry etching process. But surface roughness was changed on some area under MoSi film of Cr/MoSi/Qz. There was not detected any impurity on mask surface after plasma dry etching process. Reflectance of mask was increased after variable plasma etching treatment, especially when mask was treated with plasma including $O_2$ gas. Blank mask was positively charged when the mask was treated with Cr plasma etching gas($Cl_2:250$ sccm/He:20 $sccm/O_2:29$ seem, source power:100 W/bias power:20 W, 300 sec). But this positive charge was changed to negative charge when the mask was treated with $CF_4$ gas for MoSi plasma etching, resulting better wet cleaning. There was appeared with negative charge on MoSi/Qz mask treated with Cr plasma etching process condition, and this mask was measured with more negative after SC-1 wet cleaning process, resulting better wet cleaning. This mask was charged with positive after treatment with $O_2$ plasma again, resulting bad wet cleaning condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.60-67
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• 2012

In the study, the effect grinding condition on the workpiece arithmetical average roughness(Ra) to 10 steps leading to cutting each section with the spindle rotational speed 8000rpm and feed rate 150mm/min of grinding in GC(green silicon carbide) grinding processing after heat treatment and non heat treatment of SCM415 material. Also the following conclusions were obtained analysis of stress distribution displacement and finite elements method(FEM) on assemble parts with 3+2 axis simultaneous control through grinding and gave a load 11kg on ATC arm both sides gave a load of 11kg. For the centerline average roughness(Ra) in the heat and non-heat treatment work pieces, which were appeared the most favorable in the fifth section were $0.511{\mu}m$ and $0.514{\mu}m$, that were shown in the near the straight line section was the smallest deformation of curve. In addition, the bad surface roughness appeared on the path is too long by changing angle, the more inclined depth of cut, because the chip discharging is not smoothly.

• The Journal of Advanced Prosthodontics
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• v.10 no.4
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• pp.259-264
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• 2018

PURPOSE. The purpose of this study was to evaluate the effect of the zirconia surface architecturing technique (ZSAT) on the bond strength between veneering porcelain and zirconia ceramic. MATERIALS AND METHODS. 20 sintered zirconia ceramic specimens were used to determine the optimal surface treatment time, and were randomly divided into 4 groups based on treatment times of 0, 1, 2, and 3 hours. After etching with a special solution, the surface was observed under scanning electron microscope, and then the porcelain was veneered for scratch testing. Sixty 3 mol% yttria-stabilized tetragonal zirconia polycrystal ceramic blocks were used for tensile strength testing; 30 of these blocks were surface treated and the rest were not. Statistical analysis was performed using ANOVA, the Tukey post-hoc test, and independent t-test, and the level of significance was set at ${\alpha}=.05$. RESULTS. The surface treatment of the zirconia using ZSAT increased the surface roughness, and tensile strength test results showed that the ZSAT group significantly increased the bond strength between zirconia and veneering porcelain compared to the untreated group (36 MPa vs. 30 MPa). Optimal etching time was determined to be 2 hours based on the scratch test results. CONCLUSION. ZSAT increases the surface roughness of zirconia, and this might contribute to the increased interfacial bond strength between zirconia and veneering porcelain.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1333-1334
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• 2007

Al thin film was the most popular electrode in semiconductor and flat panel display world, because of its electrical conductivity, selectivity and easy to apply to thin film. However, Al thin films were not good to use on the bottom electrode about the crystalline growth of inorganic compound materials such as ZnO, AlN and GaN, because of its surface roughness and melting points. In this paper, we investigated Ar plasma surface treatment of Al thin film to enhance the surface roughness and electrical conductivity using the reactive ion etching system. Several process conditions such as RF power, working pressure and process time were controlled. In results, the surface roughness showed $15.53\;{\AA}$ when RF power was 100 W, working pressure was 50 mTorr and process time was 10 min. Also, we tried to deposit ZnO thin films on the each Al thin films, the upper conditions showed the best crystalline characteristics by x-ray diffraction.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.11
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• pp.1880-1888
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• 2010

This study was a preliminary investigation of the influence of surface characteristics of substrates on the detergency of particulate soil. A PET film was surface modified with NaOH and DMF for different times. The surface morphology of the film was scanned by AFM and the surface energies were calculated from the measured contact angles between several solutions and film based on a geometric mean and the Lewis acid base method. The surface morphology of the PET film treated with NaOH and DMF became more etched and swelled with an increased treatment time, respectively. The surface roughness and surface area of film treated with NaOH enlarged with increased treatment time. However, the coefficient of friction of film treated with NaOH and coefficient of friction, surface roughness, and surface area of film treated with DMF increased and then decreased with increased treatment time. The contact angle of film treated with DMF decreased with increased treatment time in water and surfactant solution; however, the effect of treatment time on the contact angle was different in both solutions for film treated with NaOH. By the treatment of PET film with NaOH and DMF, the polar group of the surface energy increased and the nonpolar group decreased; however, the change of total surface energy was not significant.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.281-286
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• 2001

Titanium alloy conducted in this experimental study has superior corrosive resistant and is mainly used in aerospace, automotive and petro-chemical industries. It is also treated with important materials of domestic goods due to improvement of the standard of living. In this study specimens were processed in the wire EDM after annealing, solution treatment and aging. Results were obtained through repeated experments of main rough process and finish process with the change of process parameters. Processing characteristics such as surface hardness, surfaces roughness, shape of processed surface and components were measured. The results confirmed that the above mentioned elements were improved in accordance with the number of process. Therefore, the optimal wire EDM condition in accord with processing characteristics is proposed in this experiment.