• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.11
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• pp.635-639
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• 2000

In this paper, a new idea about ultra-clean aligning and mounting method of FED spacers was introduced. The glass-to -glass electrostatic bonding process was employed in order to bond the micro-structures of spacers to black matrix area formed on an FED anode substrate. It is possible to get adhesive-free bonding interface and well-aligned spacer array on an FED anode substrate with a ${\pm}5{\mu}m$ accuracy. Finally, I inch-sized FED panel was demonstrated to make sure of its applicability to FED panel fabrication.

• Proceedings of the KIEE Conference
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• 2002.11a
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• pp.112-115
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• 2002

The effects of processing aids(P.A.) in semicoductive compounds(S.C.) with highly loaded carbon black for extra high voltage cables were investigated. The processability of S.C. is improved as the contents of P.A. increased, however, the electrical, mechanical properties and smoothness of S.C. grew worse, especially for the S.C. which contains 5wt% of P.A., the volume resistivity after heat cycle which shows long term reliability increased about three times after 15cycles compared to the S.C. which contains no P.A. We inferred that it is caused by the action of P.A. as the insulating sites, thermal expansion of polymer matrix which leads the length between carbon blacks to shorten, and the decrease of degree of crosslinking. The change of ion contents which means cleanliness of S.C. is not occured regardless of the addition of P.A.

• The Pure and Applied Mathematics
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• v.28 no.4
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• pp.329-341
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• 2021

In this study, we consider an efficient and accurate finite difference method for the four underlying asset equity-linked securities (ELS). The numerical method is based on the operator splitting method with non-uniform grids for the underlying assets. Even though the numerical scheme is implicit, we solve the system of discrete equations in explicit manner using the Thomas algorithm for the tri-diagonal matrix resulting from the system of discrete equations. Therefore, we can use a relatively large time step and the computation of the ELS option pricing is fast. We perform characteristic computational test. The numerical test confirm the usefulness of the proposed method for pricing the four underlying asset equity-linked securities.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.90-94
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• 1999

Field Emission display (FEDs) require enhancement in both driving methods and process techniques to improve the display image quality. However, from the point of view of manufacturing, it is difficult to find methods and techniques to realize low cost manufacturing. New and simple color phosphor screen designs were suggested with non-crossed electrode lines and full color anode panels for small area displays were demonstrated. To avoid unwanted reaction with gases produced from phosphors in a high vacuum glass container, a very thin polyimide layer was coated on the phosphor screen. Moreover, to improve the display image quality, black matrix composed of inorganic materials was fabricated. This paper describes the performance and characteristics of the new full color anode panels.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.95-97
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• 1999

A 3.12" FED panel was packaged successfully using the anode plate on which phosphors and black matrix were coated and cathode plate containing emitter arrays. The vacuum level of the panel was investigated during panel evacuation, tip-off and getter activation process. The packaged panel exhibited vacuum level below 2${\times}$10-6 Torr. Similar experiments were carried out for 10" panel made of bare plates. In addition, the vacuum level of two panels was compared continuously after tip off process; one with the getter and the other without it.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.6
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• pp.608-614
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• 2003

This study was conducted to investigate the quality characteristic of bread added with 0, 2, 4 and 8% liquid calcium acetate(LCA-breads) to the dough prepared with brown rice, vinegar and ash of black snail replacing wheat flour. The pH of the dough was 5.38 in control and 5.39∼5.42 in the LCA-broads, which showed that the higher the content of LCA, the higher the pH. There was no big difference of the baking loss between control (10.73%) and LCA-breads(10.11∼10.81%). The loaf volume index was 7.12 in the control, 7.18 in the 2% LCA-bread, while the index was 6.22 in the 4% LCA-bread, 5.80 in the 8% LCA-bread. Calcium content was 16 mg% in the control, 30, 60 and 120 mg% in 2, 4 and 8% LCA-bread, respectively. The hardness, gumminess and brittleness of LCA-breads were higher, while springiness and cohesiveness were lower than that of the control. In the LCA-breads, $L^{*}$ values were lower and $b^{*}$ value was higher than those of the control, while there were no significant difference in af values. Increasing the LCA, air cells were bigger and irregular, and starch matrix was unstable. There were no significant difference in sour and bitter taste. The scores of stickiness of the 2∼4% LCA-breads were similar to that of the control and higher in the 8% LCA-bread. The scores of the flavor and overall taste in the LCA-breads were similar to the control, while the values were lower in the 4∼8% LCA-breads. The shelf-life evaluated by the number of moldy spots was not different between the control and 2% LCA-bread, while it was extended two times in 4% and three times in the 8% LCA-bread.ead.

• Journal of Environmental Impact Assessment
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• v.27 no.5
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• pp.431-446
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• 2018

In this study, chemical characteristics of $PM_{2.5}$ samples collected in an agricultural area in Nonsan of Korea were investigated focusing on of black carbon, 3 inorganic ions and 22 trace elements. It was found that the relative error and relative standard deviation of many trace elements fell below 10%, which indicates good analytical accuracy and precision. The mean values of $PM_{2.5}$ in an agricultural area were exceeded by new Korean air quality standard of March 2018. The concentration of $PM_{2.5}$ was well correlated with those of black carbon and ions. The concentrations of trace elements were in a wide range of seven orders of a magnitude. Based on these $PM_{2.5}$ data sets, a total of 6 sources were identified using PMF (Positive Matrix Factorization; secondary aerosol (34.4%), soil/road dust (20.1%), biomass burning (16.9%), incineration/fuel combustion (13.2%), vehicle exhaust(12.2%), sea-salt (3.17%). Results of our study indicate that it is very important to control illegal burning activities in agricultural area.

• Macromolecular Research
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• v.17 no.10
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• pp.776-784
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• 2009

N,N-dimethyldodecylamine (tertiary amine)-modified MMT (DDA-MMT) was prepared as an organically modified layered silicate (OLS), after which styrene-butadiene rubber (SBR) nanocomposites reinforced with the OLS were manufactured via the latex method. The layer distance of the OLS and the morphology of the nanocomposites were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). By increasing the amount of N,N-dimethyldodecylamine (DDA) up to 2.5 g, the maximum values of torque, tensile strength and wear resistance of the SBR nanocomposites were increased due to the increased dispersion of the silicate layers in the rubber matrix and the increased crosslinking of the SBR nanocomposites by DDA itself. When SBR nanocomposites were manufactured by using the ternary filler system (carbon black/silica/OLS) to improve their dynamic properties as a tire tread compound, the tan $\delta$(at $0^{\circ}C$ and $60^{\circ}C$) property of the compounds was improved by using metal stearates instead of stearic acid. The mechanical properties and wear resistance were increased by direct substitution of calcium stearate for stearic acid because the filler-rubber interaction was increased by the strong ionic effect between the calcium cation and silicates with anionic surface. However, as the amount of calcium stearate was further increased above 0.5 phr, the mechanical properties and wear resistance were degraded due to the lubrication effect of the excessive amount of calcium stearate. Consequently, the SBR/organoclay nanocomposites that used carbon black, silica, and organoclay as their ternary filler system showed excellent dynamic properties, mechanical properties and wear resistance as a tire tread compound for passenger cars when 0.5 phr of calcium stearate was substituted for the conventionally used stearic acid.

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1439-1444
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• 2006

A $Cu^{2+}$ ion-selective membrane microelectrode has been fabricated from poly vinyl chloride (PVC) matrix membrane containing a new symmetrical hexadentate Schiff,s base 2-{1-(E)-2-((Z)-2-{(E)-2-[(Z)-1-(2-hydroxyphenyl)ethylidene]hydrazono}-1-methylpropylidene)hydrazono]ethyl}phenol (HDNOS) as a neutral carrier, Potassium tetrakis(4-chlorophenyl) borate (KTpClPB) as an anionic excluder and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The microelectrode displays linear potential response in the concentration range of $1.0\;{\times}\;10^{-5}-1.0\;{\times}\;10^{-11}$ M of $Cu^{2+}$. The microelectrode exhibits a nice Nernstian slope of 25.9 ${\pm}$ 0.3 mV $decade^{-1}$ in the pH range of 3.1-8.1. The sensor has a relatively short response time in whole concentration ranges ($\sim$5 s). The detection limit of proposed sensor is $5.0\;{\times}\;10^{-12}$ M (320 pg/L), and it can be used over a period of eight weeks. The practical utility of the sensor has been demonstrated by using it as an indicator electrode in the potentiometric titration of $Cu^{2+}$ with EDTA. The proposed membrane electrode was used for the direct determining of $Cu^{2+}$ content in black and red pepper, and in waste water samples.

• Applied Chemistry for Engineering
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• v.24 no.2
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• pp.121-125
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• 2013

In this work, we prepared the carbon paper from chopped carbon fibers using a gas diffusion matrix in polymer electrolyte membrane fuel cells by wet processing. The process of making carbon paper using wet processing is consisted of the three steps involving the dispersion of chopped carbon fibers, the preparation of the carbon fiber web, the impregnating of phenol resin. This work was focused on finding the optimal surfactant to make the carbon paper with 2D orientation of carbon fibers by investigating the dispersion state of carbon fibers in different dispersion solutions. Furthermore, the effect of phenol resin and carbon black contents on properties of electric conductivity was analyzed. As a result, it is confirmed that the carbon fiber was well dispersed when using sodium dodecyl sulfate as a surfactant, and the carbon paper with 8 wt% of phenol and 5 wt% of carbon black contents showed the most excellent electrical property.