• Journal of the Korean Chemical Society
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• v.32 no.2
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• pp.149-155
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• 1988

Pentasil zeolites, including ZSM-5, ZSM-8, ZSM-11 and silicalites, were synthesized using various organic cations. Synthesis run was carried out in a Parr pressure reactor of $2{\ell}$ capacity and a self-constructed reactor with a magnetic stirring system. The reactant materials used are colloidal silica (Snowtex), sodium aluminate, sodium chloride, TEA, TPA, TBA, Choline and water. The composition of starting materials and the reaction temperature were found to be important factors for the synthesis of uniform pentasil zeolites.

• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.31-34
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• 2010

Noble N-substituted-3-fluoropyrroles derivatives were prepared from new precursor via ring formation. The addition reaction of ethyl iododifluoroacetate to vinyl trimethylsilane under the Cu(0) catalyst resulted in the formation of ethyl-2,2-difluoro-4-iodo-4-(trimethylsilyl)butanolate, which reacted with diisobutylaluminium hydride at $-30^{\circ}C$ to yield 2,2-diflouro-4-iodo-4-(trimethylsilyl)butanal. Finally, a series of N-substituted-3-fluoropyrrole derivatives were synthesized by the reaction of 2,2-diflouro-4-iodo-4-(trimethylsilyl)butanal with $NH_4OH$ or primary amines followed by reaction with KF solution.

• Applied Biological Chemistry
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• v.34 no.3
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• pp.295-297
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• 1991

Effect of salt concentration of brined Chinese cabbage on the Kimchi fermentation was investigated. The salt concentration range was 1-5% and chemical characteristics of pH, acidity and ascorbic acid were measured during fermentation at $25^{\circ}C$. Fermentation rate was also calculated from the $CO_2$ production. It was found that the higher salt concentration caused a significant decrease in the maximum value of fermentation rate and pH reduction. Ascorbic acid content was rapidly decreased initially, followed by increase to maximum and slowely decreased thereafter. This change was more apparent at higher salt concentration.

• Environmental Engineering Research
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• v.22 no.2
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• pp.157-161
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• 2017

Simultaneous treatment of food waste leachate and power generation was investigated in an air-cathode microbial fuel cell. A TCOD removal efficiency of $95.4{\pm}0.3%$ was achieved for an initial COD concentration of 2,860 mg/L. Maximum power density ranged was maximized at $1.86W/m^3$, when COD concentration varied between 60 mg/L and 2,860 mg/L. Meanwhile, columbic efficiency was determined between 1.76% and 11.07% for different COD concentrations. Cyclic voltammetric data revealed that the oxidation peak voltage occurred at -0.20 V, shifted to about -0.25 V. Moreover, a reduction peak voltage at -0.45 V appeared when organic matters were exhausted, indicating that reducible matters were produced during the decomposition of organic matters. The results showed that it was feasible to use food waste leachate as a fuel for power generation in a microbial fuel cell, and the treatment efficiency of the wastewater was satisfied.

• Journal of the Korean institute of surface engineering
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• v.21 no.2
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• pp.39-46
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• 1988

Corrosion behavior of 5-26wt% Ni-Zn electrodeposited alloys was investigated by means of dipping electrochmical polarization measurement and galvanic coupling test. The weight loss and anodic polarization curve of coatings were measured by means of dipping and polarization measurement respectively. The galvanic protection effect of alloy coatings was measured by galvanic coupling test and the surface morpholgy of coatings was observed after corrosion testing. Our findings support thous of previous investigations showing that ${\gamma}$single phase coatings, while galvanic pprotection effect of dual phase coatings improved in comparison with ${\gamma}$single phase coating. The formation of colony in coating of ${\gamma}$and η+${\gamma}$ dual phsae caused the localized corrsion and increased the corrosion rate of the Ni-Zn coating.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1170-1172
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• 2009

• Journal of the Korean Ceramic Society
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• v.48 no.3
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• pp.211-216
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• 2011

Nickel oxide-doped ACF and $TiO_2$ composites (NiO/ACF/$TiO_2$) were prepared by a sol-gel method. The composite obtained was characterized by BET surface area measurements, X-ray diffraction, transmission electron microscopy and energy dispersive X-ray analysis. A methylene blue (MB) solution under visible light irradiation was used to determine their photocatalytic activity. Excellent photocatalytic degradation of the MB solution was observed using the $TiO_2$, Ti-ACF and NiO/ACF/$TiO_2$ composite under visible light.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.11a
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• pp.453-453
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• 2004

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1039-1049
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• 2008

Multihoming is an attractive feature for mobile nodes (MN) equipped with multiple network interfaces in a converged networking environment. However, the current standard Mobile IP (MIP) lacks support for multihomed MNs. Accordingly, this paper presents an immediate solution to resolve the problems of multihomed MNs in a UMTS and WLAN interworking system. The interworking system is based on a hierarchical architecture according to the UMTS and WLAN coverage characteristics. The MIP is only operated in the WLANs, and not in the UMTS, allowing the MIP to be used for multihomed MNs with minimal modifications. In addition, MIP binding filters are used to realize the advantages of multihoming, enabling different traffic flows to be transmitted simultaneously through different interfaces. The overall design aims to minimize the modification to the MIP and impact on existing UMTS and WLAN systems. We evaluate the performance of proposed scheme using an OPNET simulator.

• Journal of the Korean Ceramic Society
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• v.49 no.6
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• pp.511-517
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• 2012

Pd/MWCNT/$TiO_2$ composites were synthesized by a sol-gel technique using multi-walled carbon nanotubes (MWCNT), palladium (II) chlorite ($PdCl_2$) and titanium tetrachloride ($TiCl_4$) as the carbon, palladium and titanium precursors. The Pd/MWCNT/$TiO_2$ composites prepared were characterized by BET surface area measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The photocatalytic activity of the composites was evaluated using the degradation of methylene blue (MB) under UV and visible light irradiation as a model.