• Journal of the korean academy of Pediatric Dentistry
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• v.45 no.3
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• pp.290-298
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• 2018

This study aimed to evaluate surface morphology and resin tag penetration of resin infiltration into primary anterior teeth after enamel deproteinization with sodium hypochlorite (NaOCl) prior to phosphoric acid ($H_3PO_4$) etching. Ninety primary anterior teeth with non-cavitated caries lesion were devided five groups according to enamel pretreatment as follows, group I-15% hydrochloric acid (HCl) 2min. ; group II-5.25% NaOCl 1min., 35% $H_3PO_4$ 1min. ; group III-5.25% NaOCl 2min., 35% $H_3PO_4$ 1min. ; group IV-5.25% NaOCl 1min., 35% $H_3PO_4$ 2min. ; group V-5.25% NaOCl 2min., 35% $H_3PO_4$ 2min. Fifteen teeth were examined etched surface structure using field emission-scanning electron microscope. Seventy five teeth were infiltrated with resin, maximum penetration depth and percentage penetration were analysed using dual fluorescence confocal microscopy. As the application time of NaOCl increased, ratio of enamel type I, II were increased. Percentage penetration (PP) was higher in group V than group II, III (p < 0.05). PP of group IV, V did not show any differences. Non-cavitated caries of primary anterior teeth can be treated with resin infiltration. Enamel deproteinization with NaOCl prior to 35% $H_3PO_4$ etching could be an alternative of 15% HCl etching in resin infiltration.

• Journal of the Korean Electrochemical Society
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• v.11 no.2
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• pp.95-99
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• 2008

This study has made the electrode that is coated zirconium oxide on the titanium by ESD(Electrostatic spray deposition) coating methode. It has investigated the effects of the etching method of a Ti substrate as the preparation, making of zirconium oxide film and electrochemical characteristics of the electrode that is etched on the titanium. The HCl etching develops a fine and homogeneous roughness on the Ti substrate. Fabrication and material properties of the metal oxide electrode, which is known to be so effective to generate ozone and hypochlorous acid (HOCl) as power oxidant, were studied. A proper metal oxide material is focus zirconium oxide through reference. A coating method to enhance the fabrication reproducibility of the zirconium oxide electrode was used ESD coating method by zirconium oxychloride. Zirconium oxide films on the Ti substrate were tested using SEM, XRD, Cyclic voltammetry.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.211-216
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• 2012

Wet chemical etching of stainless steel foil by aqueous ferric chloride solution was investigated in this study. Effects of various process parameters (e.g. etchant agitation rate, etchant temperature, $Fe^{3+}$ ion concentration, free HCl concentration, specific gravity, etc.) on the etch rate was first studied, and it was found that the etch rate of AK (aluminum-killed) steel, chromium metal and stainless steel (STS430J1L alloy) follows the pseudo-first order reaction equation. When the fatigue ratio of etchant was kept under 16%, sludge was not formed in the solution, and the etched surface showed smooth roughness. The etch rate decreases as Baume of etchant increases, but the effect of free HCl concentration on the etch rate turned out to be minimal. Experimental data were compared with the calculated results from modeled equation, showing very good agreement.

• Journal of the Korean institute of surface engineering
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• v.53 no.5
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• pp.241-248
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• 2020

The change of the deposition behavior of diamond through a pretreatment process of the base metal prior to diamond deposition using HFCVD was investigated. To improve the specific surface area of the base material, sanding was performed using sandblasting first, and chemical etching treatment was performed to further improve the uniform specific surface area. Chemical etching was performed by immersing the base material in HCl solutions with various etching time. Thereafter, seeding was performed by immersing the sanded and etched base material in a diamond seeding solution. Diamond deposition according to all pretreatment conditions was performed under the same conditions. Methane was used as the carbon source and hydrogen was used as the reaction gas. The most optimal conditions were found by analyzing the improvement of the specific surface area and uniformity, and the optimal diamond seeding solution concentration and immersion time were also obtained for the diamond particle seeding method. As a result, the sandblasted base material was immersed in 20% HCl for 60 minutes at 100 ℃ and chemically etched, and then immersed in a diamond seeding solution of 5 g/L and seeded using ultrasonic waves for 30 minutes. It was possible to obtain optimized economical diamond film growth rates.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.412-418
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• 2020

This paper produced an automatic fluid management system that can accurately control the specific gravity of etching solution(FeCl₃), and produced a SUS MASK applied to OLED. The target was set at 0.4 mm in diameter of the hole. As a result of this misconception, the etching speed increased when the specific gravity(S.G) value of FeCl₃ was changed from 1.43 to 1.49. And when the weight was 1.49, it was found that the vertical diameter was 0.405 mm, approaching the target. When pressure injection was varied from 2.0kg/cm2 to 3.5kg/cm2, the hole diameter at 3.0 kg/cm2 averaged 0.4mm, matching the target. The characteristics of the change in gravity were analyzed by applying the additive 1.2% and setting the weight at 1.430 by mixing HCl and H2O in FeCl₃ and fixing the injection pressure at 3.0 kg/cm2. When the weight changed from 1.460 to 1.469 the etching speed increased from 0.564 to 0.540. When the weight was 1.467, the hole diameter was measured at 0.4 mm and the target was reached.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.20-27
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• 2021

Effects of the etching treatment of SAPO-34 catalyst were investigated to improve the catalytic lifetime in DTO reaction. The aqueous NH3 solution was a more appropriate treatment agent which could control the degree of etching progress, compared to that of using a strong acid (HCl) or alkali (NaOH) solution. Therefore, the effect on characteristics and lifetime of SAPO-34 catalyst was observed using the treatment concentration and time of aqueous NH3 solution as variables. As the treatment concentration or time of aqueous NH3 solution increased, the growth of erosion was proceeded from the center of SAPO-34 crystal plane, and the acid site concentration and strength gradually decreased. Meanwhile, it was found that external surface area and mesopore volume of SAPO-34 catalyst increased at appropriate treatment conditions. When the treatment concentration and time were 0.05 M and 3 h, respectively, the lifetime of the treated SAPO-34 catalyst was the longest, and was significantly enhanced by ca. 36% (based on DME conversion of > 90%) compared to that of using the untreated catalyst. The model for the etching progress of SAPO-34 catalyst in a mild treatment process using aqueous NH3 solution was also proposed.

• Journal of the Korean Electrochemical Society
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• v.9 no.2
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• pp.59-63
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• 2006

The study is coated tin(IV) oxide coated on the titanium substrate electrodes by electrodepositon and dip-coating method and studied about that physical and electrochemical characterization by coating methods. After titanium substrate is etched in HCl, electrodespotion is coated $SnCl_2{\cdot}2H_2O$ in nitrate solution by pulse technique, dip-coating method is also used $SnCl_2{\cdot}2H_2O$ in 1;1V% HCl and coated by dipping and annealing process. tin(IV) oxide coated on titanium substrate electrodes by two coating methods are studied x-ray diffraction (XRD), scanning electron microscopy (SEM) to compare physical characterization of electrode and potential window by cyclic voltammetry (CV) to observe electrochemical characterization.

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.191-193
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• 2005

This study has investigated the effects of the etching method of a Ti substrate for a metal oxide electrode on the electrochemical characteristics of the electrode. The HCl etching develops a fine and homogeneous roughness on the Ti substrate. Fabrication and material properties of the catalytic oxide electrode, which is known to be so effective to destruct refractory organics in aqueous waste, were studied. A method to enhance the fabrication reproducibility of the oxide electrode was tested for Ru, Zr, Sn oxide on the Ti substrate using SEM, XRD, Cyclic voltammetry.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.594-594
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• 2012

Al doped ZnO (AZO) thin films were deposited on textured glass substrate by magnetron sputtering method. Also, AZO films on textured glass were etched by hydrochloric acid (HCl). Average thickness of etched AZO films are 90 nm. We observed morphology of AZO film by AFM with various etchant concentration and etching time. Etched AZO films have low resistivity and high haze. The surface RMS roughness of AZO film was increased from 53.8 nm to 84.5 nm. The haze ratio was also enhanced in above 700 nm of wavelength due to light trapping effect was increased by rough AZO surface. The etched AZO films on textured glass are applicable to fabricate solar cell.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.79-84
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• 1999

the photolithographic patterning on an indium-tin oxide (ITO) glass and the electro-phoretic deposition were combined for preparing the screen of the full-color field emission display(FED). the patterns with a pixel of 400$\mu\textrm{m}$ on the ITO-glass were made by etching the ITO with well-prepared etchant consisting of HCL, H2O, and HNO3. Electrophoretic method was carried out in order to deposit each spherical red (R), green(G), and blue (B) phosphor on the patterned ITO-glass. The process parameters such as bias voltage, salt concentration, and deposition time were optimized to achieve clear boundaries. It was found that the etching process of ITO combined with electrophoretic method was cost-effective, provided distinct pattern, and even reduced process steps compared with conventional processes. The application of reverse bias to the dormant electrodes while depositing the phosphors on the stripe pattern was found to be very critical for preventing the cross-contamination of each phosphor in a pixel.