• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.589-595
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• 2013

Solution processed conjugated molecules enable to manufacture various electronic devices by unconventional and cost effective patterning methods as screen or gravure printing. Spin-coating is the most popularly used method to form conjugated polymeric film for various electronic devices. The coating method has certain disadvantages such as a large amount of unwanted wastes, difficulty forming a film with a large area, and impossible to apply roll-to-roll manufacturing. We present here a promising alternative coating method, bar-coating for conjugated polymer film and OLED with the bar coated light emitting layer. In this papers, we show atomic force microscope images of spin- and bar-coated Poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) films on substrate. The bar-coated film showed a slight lower RMS roughness (1.058 [nm]) than spin-coated film (1.767 [nm]). It means the bar-coating is suitable method to form light emitting layers in OLEDs. By using bar-coating process, an OLED obtained with 4.7 [cd/A] in maximum current efficiency.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.16-21
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• 2008

The key component of a direct methanol fuel cell (DMFC) is the membrane electrode assembly (MEA), which comprises a polymer electrolyte membrane and catalyst layers (anode and cathode electrode). Generally the catalyst layer is coated on the porous electrode supporter (e.g. carbon paper or cloth) using various coating methods such as brushing, decal transfer, spray coating and screen printing methods. However, these methods were disadvantageous in terms of the uniformity of catalyst layer thickness, catalyst loss, and coating time. In this work, we used bar-coating method which can prepare the catalyst layer with uniform thickness for MEA of DMFC. The surface and cross-section morphologies of the catalyst layers were observed by SEM. The performances and resistance of the MEAs were investigated through a single cell evaluation and impedance analyzer.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.416-416
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• 2016

Organic-inorganic metal halide perovskite solar cells have received attention because it has a number of advantages with excellent light harvesting, high carrier mobility, and facile solution processability and also recorded recently power conversion efficiency (PCEs) of over 20%. The major issue on perovskite solar cells have been reached the limit of small area laboratory scale devices produced using fabrication techniques such as spin coating and physical vapor deposition which are incompatible with low-cost and large area fabrication of perovskite solar cells using printing and coating techniques. To solution these problems, we have investigated the feasibility of achieving fully printable perovskite solar cells by the blade-coating technique. The blade-coating fabrication has been widely used to fabricate organic solar cells (OSCs) and is proven to be a simple, environment-friendly, and low-cost method for the solution-processed photovoltaic. Moreover, the film morphology control in the blade-coating method is much easier than the spray coating and roll-to-roll printing; high-quality photoactive layers with controllable thickness can be performed by using a precisely polished blade with low surface roughness and coating gap control between blade and coating substrate[1]. In order to fabricate perovskite devices with good efficiency, one of the main factors in printed electronic processing is the fabrication of thin films with controlled morphology, high surface coverage and minimum pinholes for high performance, printed thin film perovskite solar cells. Charge dissociation efficiency, charge transport and diffusion length of charge species are dependent on the crystallinity of the film [2]. We fabricated the printed perovskite solar cells with large area and flexible by the bar-coating. The morphology of printed film could be closely related with the condition of the bar-coating technique such as coating speed, concentration and amount of solution, drying condition, and suitable film thickness was also studied by using the optical analysis with SEM. Electrical performance of printed devices is gives hysteresis and efficiency distribution.

• Computers and Concrete
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• v.21 no.2
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• pp.181-187
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• 2018

In order to solve the life prediction problem of damaged coating steel bar in magnesium cement concrete, this study tries to establish the marginal distribution function by using the corrosion current density as a single degradation factor. Representing the degree of steel corrosion, the corrosion current density were tested in electrochemical workstation. Then based on the Copula function, the joint distribution function of the damaged coating was established. Therefore, it is indicated that the corrosion current density of the bare steel and coated steel bar can be used as the boundary element to establish the marginal distribution function. By using the Frank-Copula function of Copula Archimedean function family, the joint distribution function of the damaged coating steel bar was successfully established. Finally, the life of the damaged coating steel bar has been lost in 7320d. As a new method for the corrosion of steel bar under the multi-dimensional factors, the two-dimensional Copula function has certain practical significance by putting forward some new ideas.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.608-613
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• 2010

This study is on development of UV-cured water soluble coating composition which have more improved anti-cigar burning to prevent a surface of PVC tile from damage of heat. To make an anti-cigar burning coating solution, thermostable agent that synthesize main materials phosphorus compound, guanidine and ammonium phosphate dibasic used temporary flame retardants, changing their contents from 10 to 30wt% against quantities of resin and compounded. After coating PVC tiles using bar-coating method that can adjust a thickness, we estimated surface properties of coated layer such as anti-cigar burning, adhesive power, chemical resistance, thickness of coating, and so on. Results showed that a coating composition added 30 wt% of phosphorus compound and coated with No.12 bar-coater had the best optimized surface property in anti-cigar burning effect, adhesive power and chemical resistance. Also, we could find anti-cigar burning effect was improved as thermostable agents content and coating thickness increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1741-1746
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• 2010

This study is on development of UV-cured anti-stain coating compounds which have more improved anti-stain function to prevent a surface of PVC tile from stain. To make an anti-stain coating composition, water soluble antistatic agent made from ammonium(IV) salt, antistatic agents for acrylic and polyurethane were used. Their contents varied from 5 to 20wt% against quantities of resin in coating composition. After coating PVC tiles using bar-coating method that can adjust a thickness, we estimated surface properties of coated layer such as anti-stain, electric resistance, adhesive power, thickness of coating, and so on. Results showed that a coating composition added 15wt% of water soluble antistatic agent and coated with No.12 bar-coater had the optimum surface property in electric resistance($3.24{\times}10^9{\Omega}/cm^2$), anti-stain(ink Test, Dust Test) and adhesive power. We could also find electric resistance and anti-stain effect were improved as antistatic agent content increased. However, excessive addition of antistatic agents(over 20wt%) caused the migration.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.3
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• pp.62-69
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• 1995

In order to investigate the effect of TiN coating on corrosion fatigue behavior of metal, the rotary bending corrosion fatigue tests were carried out in 3% NaCl solution by using the round bar specimens of high-speed steel, SKH-9, coated with TiN by PVD method. From the experimental results, fatigue strength of TiN coating steel in air was obvious improvement as compared with that of the substrate because of the restriction of dislocation movement in near surface of the substrate by hard thin film. In 3% NaCl solution, corrosion fatigue life of TiN coating specimen in high stress level was improvement same as in air. But in low stress level, corrosion fatigue life of TiN coating one was equivalent to that without coating, due to much crack initiated from corrosion pits formed at the substrate by failure of coating layer.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.117-122
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• 2001

Recently, epoxy-coated re-bar used to the structure partly and put to practical use step, but not economical and appeared to the defect of deterioration of long term bond strength between concrete. The method for complement the defect of epoxy coated re-bar, study of polymer cement slurry coated re-bar started and basic properties appeared to excellent, but study of bond properties embedded in concrete specimens insufficient until now. This study attempts to examination of using possibility for bond strength of polymer cement slurry coated re-bar between concrete specimens compare to ACI Code and KS Code through pull-out test of 15cm$\times$15cm$\times$15cm specimens with polymer cement slurry coated re-bar as polymer cement ratio 50%, 100%, 150%, coating thickness 250${\mu}{\textrm}{m}$, 440${\mu}{\textrm}{m}$ and curing age. In the results of this study, the bond strength of polymer cement slurry coated re-bar compare to plain re-bar, epoxy coated re-bar decreased St/BA-modified polymer cement slurry coated re-bar, but bond strength of PA-modified polymer cement slurry coated re-bar appeared to excellent results. The bond properties of polymer cement slurry coated re-bar between concrete will be obtain more precise results according to compressive strength change of concrete and re-bar diameter size.

• International Journal of Safety
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• v.10 no.1
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• pp.16-21
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• 2011

In this thesis, appearance inspection, compressive strength of concrete test, arrangement of bar inspection, survey, and bearing stress analysis were performed on a damaged coping of reinforced concrete pier to investigate the damage cause. According to the performed a series of inspections, it was found that the coping of pier was damaged during PSC (Pre-stressed Concrete) beam construction. In this thesis, the repair method for damaged pier was studied. The repair procedure used in this thesis was follows : chipping for damaged part, clean by high-pressure, installation of wire mesh, coating of surface hardening, construction of section restoration material, copula grinding, and prevent coating for far-infrared radiation.

• Journal of Ginseng Research
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• v.33 no.3
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• pp.229-233
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• 2009

The centrifugal coating granulating system, a new method of preparing red ginseng extract pills, has been developed. The red ginseng extract was first powdered with 85.5% of edible ethanol and dried for 3 to 4 hours at 50$^{\circ}C$. The powders were fed in chamber of centrifugal coating granulating system and then granulated, sequentially. The centrifugal system operated at 20 to 50$^{\circ}C$ of inlet temperature, 1 to 1,000 g/min of feeding speed, 60 to 70$^{\circ}C$ of atmosphere temperature of intake, 3.0 to 4.0 bar of spray atmosphere pressure, 1,000 to 1,500 rpm of centrifugal plate speed and 25 to 40$^{\circ}C$ of outlet temperature. The product yield was about 85% and preparation time was 7 to 8 hours. Especially, major ginsenoside components of red ginseng were not decomposed after processing of red ginseng extract pill.