• Korean Journal of Medicinal Crop Science
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• v.21 no.1
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• pp.7-19
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• 2013

This study was carried out to select new pelleting binder and material for seeds from Fraxinus rhynchophylla Hance and Alnus sibirica Fisch. ex Turcz. The optimum treatments of the various concentrations and species of priming agents to improve seed germination of both woody medicinal plants were also estimated. Germinability was increased when the seeds of Fraxinus rhynchophylla Hance was soaked in -1.0 MPa of PEG6000 solution at $15^{\circ}C$ for 4 days significantly, the optimum treatment for improving germination of Alnus sibirica Fisch. ex Turcz was observed when the tested seeds was soaked in 100 mM of KCl at $15^{\circ}C$ for 4 days. The influence of physical and chemical properties of pelleting solid materials, the mixture of gypsum, diatomaceous earth, dalma ceramic and vermicuolite (6:1:1:1 ratio) were found as the best pelleting materials for Fraxinus rhynchophylla Hance and Alnus sibirica Fisch. ex Turcz. seeds. To satisfy the requirements of absorption and compatibility for multi-layer seed pelleting, SGPA (Starch-grafted cross-linked polyacrylates) hydrogel was prepared using starch, acrylonitrile, ceric ammonium nitrate, nitric acid, methyl alcohol and potassium hydroxide. The resulting SGPA hydrogel showed high water absorption but not plant compatibility. It suggested that seed pelleting using pelleting materials and SGPA hydrogel (multi-layer coating) after priming agent treatment is to increase germinability and seedling growth and it can reduced irrigation labours and can also save seed.

• Journal of the Korean Vacuum Society
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• v.11 no.3
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• pp.176-182
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• 2002

Amorphous $TiO_2$ thin films were deposited on glass substrates by ion beam sputtering in which the ratio of $O_2$/Ar gas used as discharged gas was varied from 0 to 2. After optical and microstructure properties and chemical composition of thin films was analyzed, antireflection coating layers were fabricated with $SiO_2$/$TiO_2$ multi-layers. Thin films deposition was performed at room temperature and ion beam voltage and ion current density for sputtering of target were fixed at 1.2 kV and 200 $\mu\textrm{A}/\textrm{cm}^2$, respectively. Refractive indexs of the deposited $TiO_2$films were 2.40-2.45 at a wavelength of 633 nm. $TiO_2$films had high transmission and stoichiometry when ratio of $O_2$/Ar was 1. Rms roughness of deposited $TiO_2$ film was below 7 $\AA$. In excessive $O_2$ environments, however Rms roughness increased over 50 $\AA$. Transmittance decreased by scattering of rough surface. Reflectance of $SiO_2$/$TiO_2$multi-layers was below 1% in visible light.

• Membrane Journal
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• v.27 no.2
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• pp.167-181
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• 2017

Graphene-based materials have been considered as a promising membrane material, due to its easy processability and atomic thickness. In this study, we studied on gas permeation behavior in few-layered GO membranes prepared by spin-coating method. The GO membrane structures were varied by using different GO flake sizes and GO solutions at various pH levels. The GO membranes prepared small flake size show more permeable and selective gas separation properties than large one due to shortening tortuosity. Also gas transport behaviors of the GO membranes are sensitive to slit width for gas diffusion because the pore size of GO membranes ranged from molecular sieving to Knudsen diffusion area. In particular, due to the narrow pore size of GO membranes and highly $CO_2$-philic properties of GO nanosheets, few-layered GO membranes exhibit ultrafast and $CO_2$ selective character in comparison with other gas molecules, which lead to outstanding $CO_2$ capture properties such as $CO_2/H_2$, $CO_2/CH_4$, and $CO_2/N_2$. This unusual gas transport through multi-layered GO nanosheets can explain a unique transport mechanism followed by an adsorption-facilitated diffusion behavior (i.e., surface diffusion mechanism). These findings provide the great insights for designing $CO_2$-selective membrane materials and the practical guidelines for gas transports through slit-like pores and lamellar structures.

• Applied Chemistry for Engineering
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• v.24 no.1
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• pp.31-37
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• 2013

Lowering surface reflectance of Si wafers by texturization is one of the most important processes for improving the efficiency of Si solar cells. This paper presents the results on the effect of texturing using acidic solution mixtures containing the catalytic agents to moderate etching rates on the surface morphology of mc-Si wafer as well as on the performance parameters of solar cell. It was found that the treatment of contaminated crystalline silicon wafer with $HNO_3-H_2O_2-H_2O$ solution before the texturing helps the removal of organic contaminants due to its oxidizing properties and thereby allows the formation of nucleation centers for texturing. This treatment combined with the use of a catalytic agent such as phosphoric acid improved the effects of the texturing effects. This reduced the reflectance of the surface, thereby increased the short circuit current and the conversion efficiency of the solar cell. Employing this technique, we were able to fabricate mc-Si solar cell of 16.4% conversion efficiency with anti-reflective (AR) coating of silicon nitride film using plasma-enhanced chemical vapor deposition (PECVD) and Si wafers can be texturized in a short time.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.41-47
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• 2003

For the development of low temperature anode-supported planar solid oxide fuel cell, the planar anode supports with the thickness of 0.8 to 1 mm and the area of 25, 100 and $150\;cm^2$ were fabricated by the tape casting method. The strength, porosity, gas permeability and electrical conductivity of the planar anode support were measured. The porosity of anode supports sintered at $1400^{\circ}C$ and then reduced in$H_2$ atmosphere was increased from $45.8\%\;to\;53.9\%$. The electrical conductivity of the anode support was $900 S/cm\;at\; 850^{\circ}C$ and its gas permeability was 6l/min at 1 atm in air atmosphere. The electrolyte layer and cathode layer were fabricated by slurry dip coating method and then had examined the thickness of $10{\mu}m$ and the gas permeability of 2.5 ml/min at 3 atm in air atmosphere. As preliminary experiment, cathode multi-layered structure consists of LSM-YSZ/LSM/LSCF. At single cell test using the electrolyte layer with thickness of 20 to $30{\mu}m$, we achieved $300\;mA/cm^2$ and 0.6V at $750^{\circ}C$

• Journal of the Microelectronics and Packaging Society
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• v.24 no.4
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• pp.39-46
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• 2017

This paper presents the fabrication of ceramic insulation layer on metallic heat spreading substrate, i.e. an insulated metal substrate, for planar type heater. Aluminum alloy substrate is preferred as a heat spreading panel due to its high thermal conductivity, machinability and the light weight for the planar type heater which is used at the thermal treatment process of semiconductor device and display component manufacturing. An insulating layer made of ceramic dielectric film that is stable at high temperature has to be coated on the metallic substrate to form a heating element circuit. Two technical issues are raised at the forming of ceramic insulation layer on the metallic substrate; one is delamination and crack between metal and ceramic interface due to their large differences in thermal expansion coefficient, and the other is electrical breakdown due to intrinsic weakness in dielectric or structural defects. In this work, to overcome those problem, selected metal oxide buffer layers were introduced between metal and ceramic layer for mechanical matching, enhancing the adhesion strength, and multi-coating method was applied to improve the film quality and the dielectric breakdown property.

• Korean journal of food and cookery science
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• v.25 no.2
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• pp.252-259
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• 2009

Ergosterol is the significant component of the cell wall of fungi. Its presence is regarded as evidence of fungi contamination in grain and other foods. Many studies on ergosterol detection have been carried out using chemical methods, but those methods required complicated pre-treatments and long analysis times. In this study, an amperometric biosensor was developed for fast and precise ergosterol detection. The biosensor system used the electron transfer of hydrogen peroxide produced from the reaction of ergosterol with cholesterol oxidase. The biosensor system consisted of a peristaltic pump, a syringe loading sample injector, an enzyme reactor, a fabricated flow-through cell containing a working electrode, a reference electrode and a counter electrode, and a potentiostat/recorder. The working electrode was prepared by coating modified multi-wall carbon nanotube (MWNT) on glassy carbon electrode. The $MWNT-NH_2$ coated glassy carbon electrode linearly responded to hydrogen peroxide in the range of $1{\times}10^{-5}{\sim}8{\times}10^{-5}$ M with a detection limit of $10^{-7}$ M in the basic performance test. The currents produced from the ergosterol biosensor showed the linearity in a range from $1.0{\times}10^{-6}$ M to $1.0{\times}10^{-5}$ M ergosterol.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.5
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• pp.481-486
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• 2011

It is important to predict the behavior of a liquid film around a rotating cylinder in the film coating process of the steel industry. When the cylinder rotates, the behavior of the liquid film on the rotating cylinder surface is influenced by the cylinder diameter, the rotation speed, the gravitational force, and the fluid properties. These parameters determine the liquid film thickness and the rise of the film on the cylinder surface. In the present study, the two-phase interfacial flow of the liquid film on the rotating cylinder were numerically investigated by using a VOF method. For various rotation speeds, cylinder diameters and fluid viscosities, the behavior of liquid film on the rotating cylinder were predicted. Thicker film around the rotating cylinder was observed with an increase in the rotation speed, cylinder diameter, and fluid viscosity. The present results for the film thickness agreed well with available experimental and analytical results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.475-480
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• 2017

In this paper, the conductivity of the fine pattern is improved in the insulating substrate by laser-induced forward transfer (LIFT) process. The high laser beam energy generated in conventional laser induced deposition processes induces problems such as low deposition density and oxidation of micro-patterns. These problems were improved by using a polymer coating layer for improved deposition accuracy and conductivity. Chromium and copper were used to deposit micro-patterns on silicon wafers. A multi-pulse laser beam was irradiated on a metal thin film to form a seed layer on an insulating substrate(SiO2) and electroless plating was applied on the seed layer to form a micro-pattern and structure. Irradiating the laser beam with multiple scanning method revealed that the energy of the laser beam improved the deposition density and the surface quality of the deposition layer and that the electric conductivity can be used as the microelectrode pattern. Measuring the resistivity after depositing the microelectrode by using the laser direct drawing method and electroless plating indicated that the resistivity of the microelectrode pattern was $6.4{\Omega}$, the resistance after plating was $2.6{\Omega}$, and the surface texture of the microelectrode pattern was uniformly deposited. Because the surface texture was uniform and densely deposited, the electrical conductivity was improved about three fold.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.3
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• pp.377-387
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• 2006

The objective of this study was to evaluate the influence of multiple adhesive coatings on the thickness of hybrid and adhesive layer and shear bond strength(SBS) of self-etch adhesives and self-etch primer adhesives. The buccal or lingual crown dentin of extracted human molars was used. Self-etch adhesives or self-etch primer adhesives were applied 1, 2 and 3 times on the dentin before light curing. In another group adhesives were reapplied after light curing first layer. Treated surfaces were prepared to measure the thickness of hybrid and adhesive layer with SEM, and shear bond strength to dentin using an Instron machine. The following results were obtained : 1. The adhesive layers increased with the number of coatings(p<0.05) with all adhesives. Adpor Prompt L-Pop and Xeno III were significantly thinner than self-etch primer adhesives (p<0.05). 2. The thickness of hybrid layers increased with the number of coatings (p<0.05). 3. The shear bonding strength of Unifil Bond and Clearfill SE Bond were higher than Scotchbond Multipurpose Plus and Adpor Prompt L-Pop (p<0.05), and similar with Xeno III. 4. The shear bond strength increased significantly with the number of coatings in Adpor Prompt L-Pop(p<0.05), but decreased at 3 times in AdheSE Bond(p>0.05). 5. In Adpor Prompt L-Pop and Xeno III, the shear bond strength decreased when adhesives were reapplied after curing the first adhesive layer.