• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.455-460
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• 2005

Deposition of TiN$_{x}$ film was conducted with a DC sputtering technique. The effect of the processing parameters such as substrate temperature, deposition time, working pressure, bias power, and volumetric flowing rate ratio of Ar to N$_{2}$ gas on the resistivity of TiN$_{x}$ film was systematically investigated. Three kinds of substrates, soda-lime glass, (100) Si wafer, and 111m thermally grown (111) SiO$_{2}$ wafer were used to explore the effect of substrate. The phase of TiN$_{x}$ film was analyzed by XRD peak pattern and deposition rate was determined by measuring the thickness of TiNx film through SEM cross-sectional view. Resistance was obtained by 4 point probe method as a function of processing parameters and types of substrates. Finally, optimum condition for synthesizing TiN$_{x}$ film having lowest resistivity was discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.615-616
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• 2006

A micro-fuel processor system integrating steam reformer and partial oxidation reactor was manufactured using low temperature cofired ceramic (LTCC). A CuO/ZnO/$Al_2O_3$ catalyst and Pt-based catalyst prepared by wet impregnation were used for steam reforming and partial oxidation, respectively. The performance of the LTCC micro-fuel processor was measured at various operating conditions such as the effect of the feed flow rate, the ratio of $H_2O/CH_3OH$, and the operating temperature on the LTCC reformer and CO clean-up system. The catalyst layer was loaded with "Fill and Dry" coating for small volume. The product gas was composed of $70\sim75%$ hydrogen, $20\sim25%$ carbon dioxide, and $1\sim2%$ carbon monoxide at $250\sim300^{\circ}C$, respectively.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.4
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• pp.66-73
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• 2008

When coated paperboard is printed, pressed into a groove with a creasing rule and folded, white line cracking occurs along the crease due to intensive mechanical pressure. The cracking will deteriorates product quality and waste resources. Effects of creasing pressure and ink dosage on the foldability of coated board were investigated. It was shown that applying an optimum pressure is important during creasing. When the pressure was too low, the crease formed was not sufficiently deep enough to enable precise folding. When an excess pressure was applied, fiber bonding was destroyed, resulted in unsatisfactory cracking. When the coated board was folded in machine direction (MD), long cracks were formed along MD. When it folded in cross direction (CD), the cracks were shorter and formed perpendicular to CD. Printing promoted cracking due to the decrease in flexibility of coated board. In addition, uneven ink film layer on the coating layer caused worse cracking.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.182-187
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• 2005

A large area micro mirror is an optical element that functions as changing an optical path by reflection in integrated optical system. We fabricated the large area silicon mirror by anisotropic etching using MEMS for implementation of integrated optical pickup. In this work, we report the optimum conditions to better fabricate and design, greatly improve mirror surface quality. To obtain mirror surface of $45^{\circ},\;9.74^{\circ}$ off-axis silicon wafer from (100) plane was used in etching condition of $80^{\circ}C$ with 40wt.% KOH solution. After wet etching, polishing process by MR fluid was applied to mirror surface for reduction of roughness. In the next step, after polymer coating on the polished Si wafer, the Si mirror was fabricated by UV curing using a trapezoid bar-type way structure. Finally, we obtained peak to valley roughness about 50 nm in large area of $mm^2$ and it is applicable to optical pickup using blu-ray wavelength as well as infrared wavelength.

• Journal of Environmental Science International
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• v.16 no.10
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• pp.1111-1118
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• 2007

A bismuth-coated carbon fiber microelectrode was prepared using cyclic voltammetry (CV). An analytical application was performed for the copper analysis with Square Wave Stripping Voltammetry (SWSV). Gallic acid n-propyl ester (PG) was used for the complex formation with a copper ion, and electrochemical measurements were performed with a pre-amplifier of a low-current module for nano am per detection. The effects of various parameters on the response were optimized. Analytical working ranges of $0.03-25.9\;{\mu}gl^{-1}$ and $0-25\'mgl^{-1}$ Cu(II) were obtained. The relative standard deviation at $13\;mgl^{-1}$ Cu was 0.9% (n = 12) in optimum conditions. The detection limit was found to have been $0.019\;{\mu}gl^{-1}$, with a 30-sec accumulation time. The developed methods were applied to a copper assay in water samples.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_2
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• pp.1037-1045
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• 2022

In this study, nanoscale Al₂O3 ceramic particles were used due its exceptionally high hardness characteristics, chemical stability, and wear resistance properties. These nanoparticles will be used to investigate the optimal process conditions for the electro co-deposition of the Ni-Al₂O₃ composite coatings. A Watts bath electrolytic solution of a controlled composition along with a fixed agitation speed was used for this study. Whereas the current density, the pH value, temperature and concentration of the nano Al₂O₃ particles of the electrolyte were designated as the manipulative variables. The experimental design method was based on the orthogonal array to find the optimum processing parameters for the electro co-deposition of Ni-Al₂O₃ composite coatings. The result of confirmation experimental based on the optimal processing condition through the analysis of variance ; EDX analysis found that the ratio of alumina increased to 8.65 wt.% and subsequently the overall hardness increased to 983 Hv. Specially, alumina were evenly distributed on Nickel matrix and particles were embedded more firmly and finely in Nickel matrix.

• Membrane Journal
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• v.8 no.1
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• pp.50-58
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• 1998

Protein affinity membranes were prepared via coating of chitosan gel on the porous flat and hollow-fiber polysulfone membranes, followed by the immobilization of the reactive dye (Cibacron Blue 3GA) to the chitosan gel. Maximum protein binding capacity of these affinity membranes was about 70 $\mu{g/cm}^2$. Using the affinity flat membrane module, the elution chromatography of human serum albumin (HSA) was performed to determine the optimum condition of eluent buffer. The optimum condition of eluent was the universal buffer solution of 0.06 M concentration containing 1 M KCl at pH 10. For the frontal chromatography of HSA using the flat module, the dynamic protein binding capacity was rapidly decreased from the equilibrium values with increasing flow rate and HSA concentration of the loading solution. However, in the case of hollow-fiber module, the dynamic binding capacity was maintained an equilibrium value without depending on the operating conditions. These results showed that the hollow-fiber module was more effective than the flat module as an affinity chromatography column.

• Korean Journal of Environmental Agriculture
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• v.13 no.1
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• pp.76-82
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• 1994

A competitive indirect enzyme-linked immunosorbent assay(ELISA) was developed to detect and quantify levels of the fungicide metalaxyl in crops. Antiserum against metalaxyl was demonstrated in rabbits immunized with metalaxyl-human serum albumin(HSA) conjugate. Metalaxyl-protein conjugate was prepared by mixed anhydride and peptide coupling method with EDC. In this assay, metalaxyl-ovalbumin(OA) was $coated(8{\mu}g/ml)$ on the microtiter plate, which was incubated for 1 hr at $4^{\circ}C$ or 4 hr at $37^{\circ}C$ with diluted antiserum(1:2,000). The optimum volume ratio of antigen and antibody mixture was 0.5: 1, which was incubated for 1 hr at $20^{\circ}C$. The detection of metalaxyl bound on the surface of wells was determined by the reaction(30 min) of antirabbit Ig G-peroxidase conjugate with its substrate.

• Journal of the Korea institute for structural maintenance and inspection
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• v.12 no.1
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• pp.193-202
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• 2008

This paper investigates experimentally the confining effect, strengthening capacity and rebound rate of sprayed Fiber-Reinforced-Polymer (SFRP). From the method, resin and chopped fibers are sprayed separately from the nozzle with high pressure, and then they are attached to the concrete surface, so structure could be repaired. To evaluate the strengthening effect of sprayed FRP, cylindrical specimens and beam specimens were strengthening with SFRP. As main material of FRP, glass fiber and polyester resin are used. To investigate the optimum condition of sprayed FRP, the effects of fiber length, coating thickness, fiber volume ratio and concrete strength were examined. Capacities of sprayed FRP method were also compared to the FRP sheet method. In case of the sprayed FRP, rebound rate is important parameter considering economical efficiency and constructibility, so rebound rate of was discussed. From the test results, optimum conditions of sprayed FRP were determined. SFRP method showed superior strengthening capacities than FRP sheet method.

• Korean Journal of Materials Research
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• v.9 no.11
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• pp.1055-1061
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• 1999

Indium Tin Oxide (ITO) films were fabricated by vacuum deposition technique and their microwave shielding properties were investigated for the application to the transparent shield material. The vacuum coating was conducted in a RF co-sputtering machine. The film composition and structure associated with the sputtering conditions (argon and oxygen pressure. substrate temperature. RF input power) were investigated for the attainment of high electrical conductivity and good transparency. The electrical conductivity of IT0 films fabricated under the optimum deposition conditions (substrate temperature : $300^{\circ}C$. Ar flow rate : 20 sccm, Oxygen flow rate : 10 sccm, In/Sn input power : 50/30 W) showed 5.6$\times10^4$mho/m. The optical transparency is also considerably good. The microwave shielding properties including the dominant shielding mechanism are investigated from the electrical conductivity, thickness and skin depth of the ITO films. The total shielding effectiveness is then estimated to be 26 dB, which provides a suggestion that the IT0 films can be effectively used as the transparent shield material.