• Journal of the Korean Institute of Gas
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• v.26 no.3
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• pp.21-26
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• 2022

Zinc is emerging as a environment-friendly plating material to replace cadmium, which is harmful to the human body, to prevent hydrogen gas penetration or release from metal materials. Electroplating of Zn and Zn alloys, which is usually performed in an aqueous acidic atmosphere, has disadvantages such as low coulombic efficiency, corrosion, and hydrogen release, resulting in industrial use difficult. In this study, a deep-eutectic solvent was synthesized using choline chloride and ethylene glycol. Using this as a solvent, an electrolyte for Zn plating was prepared, and then zinc was plated on the STS 304 substrate. The surface microstructure and roughness were observed using SEM and AFM. The crystal structure of the electro-plated film was analyzed using XRD. Finally, the preventing effects of hydrogen release through Zn-based deep-eutectic plating on the STS 304 substrate were compared with the uncoated substrate.

• Membrane Journal
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• v.14 no.4
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• pp.275-288
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• 2004

Carbon dioxide was absorbed into water-in-oil (w/o) emulsion composed of aqueous 2-amino-2-methyl-1-propanol (AMP) droplets as a dispersed phase and benzene solutions of polybutene and polyisobutylene as a continuous phase in a flat-stirred vessel to investigate the effect of non-Newtonian rheological behavior on the rate of chemical absorption of $CO_2$, where the reaction between $CO_2$ and AMP in the aqueous phase was assumed to be a pseudo-first-order reaction. It was expressed that PIB with elastic property made the rate of chemical absorption of $CO_2$ accelerated by comparison of mass transfer coefficient of $CO_2$ in the non-Newtonian liquid with that in the Newtonian liquid.

• Fashion & Textile Research Journal
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• v.8 no.5
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• pp.577-584
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• 2006

The binding of heavy metal ions onto cross-linked chitosan in dilute aqueous solution has been investigated as a function of pH (4.0 and 7.0), agitation period (10-180min) and concentration of various metal cations (5, 10, 50 and 100ppm). In order to obtain adsorbents that are insoluble and stable, and prevent the dissolution loss of chitosan into an acidic aqueous solution, chitosan flakes were cross-linked with epichlorohydrine (ECH) and its adsorption behavior was compared with that of the non cross-linked chitosan. An advantage of ECH is that it does not eliminate the cationic amine functional group of chitosan. In terms of adsorption ratio, the chitosan cross-linked at an ECH was inferior to original chitosan and was found that chitosan has a selectivity much remarkable than the cross-linked chitosan in low concentrated metal solutions. However, no significant decreases in the adsorption ratios were observed between the cross-linked ECH-chitosan and the non cross-linked chitosan concerning the adsorption of $Ni^{2+}$, $Co^{2+}$, $Pb^{2+}$ and $Zn^{2+}$ acidic solution.

• Journal of Electrochemical Science and Technology
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• v.6 no.2
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• pp.50-58
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• 2015

There is a great deal of current interest in the development of rechargeable batteries with high energy storage capability due to an increasing demand for electric vehicles (EVs) with driving ranges comparable to those of gasoline-powered vehicles. Among various types of batteries under development, a Li-O₂ battery delivers the highest theoretical energy density; thus, it is considered a promising energy storage technology for EV applications. Despite the fact that extensive research efforts have been made in the field of Li-O₂ batteries in recent years, there are still many technical challenges to be addressed, such as low round-trip efficiency, poor reversibility, and poor power capability. In this article, we provide a short review on the fundamental electrochemistry of Li-O₂ batteries with non-aqueous electrolytes and on electrode materials that have been employed in cathodes (oxygen electrodes). The major aim of this mini-review is to highlight the physical and electrochemical origins of scientific challenges facing Li-O₂ battery technology and to overview the strategies proposed to overcome them.

• Fibers and Polymers
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• v.6 no.1
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• pp.1-5
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• 2005

In this study, we attempted to evaluate a novel use of sericin-fixed silk fiber (SFx) as an immobilization support of enzyme. Sericin was fixed on the silk fiber using glutaraldehyde as a fixation reagent. After 6 hours of fixation, the degree of fixation increases linearly with linear decrease of the amount of bound $\alpha$-chymotrypsin (CT). This suggests that the increase of the degree of fixation is due to the further crosslinking of free aldehyde groups on the surface of sericin-fixed silk fiber (SFx). Even though perfect fixation was not achieved, sericin did not dissolve seriously and could be removed by further washing. The specific activity did not differ significantly after 6 hours of fixation. The activity of immobilized CT on SFx decreased to its half after 6 hours of incubation at 50$^{\circ}C$. However, it retained $78\%$ of initial activity even after 1 hour of treat­ment with $100\%$ ethanol. As a result, the SFx could be used as an immobilization support of enzyme in non-aqueous media at ambient temperature.

• Advances in Traditional Medicine
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• v.8 no.1
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• pp.59-66
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• 2008

This study was undertaken to evaluate the antioxidant potential of A. lanata on oxalate mediated free radical toxicity in ethylene glycol induced calcium oxalate urolithic rats. Calcium oxalate (CaOX) stone was induced by 0.75% ethylene glycol in drinking water for 28 days. From $29^{th}$ day onwards, the CaOX urolithic rats were treated with A. lanata aqueous suspension (2,000 mg/kg body weight/dose/day) orally for another 28 days. At the end of experimental periods the animals were sacrificed, samples were collected and analyzed the lipid peroxidation product, protein oxidation product, enzymatic and non-enzymatic antioxidants in normal and experimental groups. Lipid peroxidation and protein oxidation products were significantly elevated while enzymatic and non-enzymatic antioxidant levels were significantly decreased in ethylene glycol induced CaOX urolithic rats when compared with control rats. The above alterations were reverted to near control in rats treated with aqueous suspension of A. lanata. This study suggests that A. lanata could prevent the free radical formation from calcium oxalate urolithiasis in rats and protecting the renal cells from oxidative injury.

• Clean Technology
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• v.14 no.4
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• pp.281-286
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• 2008

Absorption rate of carbon dioxide was measured in the aqueous polyacrylamide (PAA) solution containing triethanolamine (TEA) of $0{\sim}2.0\;kg\;mol/m^3$ in a flat-stirred vessel with an impeller of 0.05 m and agitation speed of 50 rpm at $25^{\circ}C$ and 101.3 kPa. The chemical absorption rate of $CO_2$ was estimated by mass transfer mechanism based on the film theory using the physicochemical properties containing the liquid-side mass transfer coefficient of $CO_2$ and the kinetics of reaction between $CO_2$ and TEA to compare with the measured rate. The aqueous PAA solution acted as a reducing agent by viscoelastic property of non-Newtonian liquid based on the same viscosity of the solution.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.915-923
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• 2013

Decomposition of non-biodegradable contaminants such as phenol contained in water was investigated using a dielectric barrier discharge (DBD) plasma reactor in the aqueous solutions with continuous oxygen bubbling. Effects of various parameters on the removal of phenol in aqueous solution with high-voltage streamer discharge plasma are studied. In order to choose plasma gas, gas of three types (argon, air, oxygen) were investigated. After the selection of gas, effects of 1st voltage (80 ~ 220 V), oxygen flow rate (2 ~ 7 L/min), pH (3 ~ 11), and initial phenol concentration (12.5 ~ 100.0 mg/L) on phenol degradation and change of $UV_{254}$ absorbance were investigated. Absorbance of $UV_{254}$ can be used as an indirect indicator of phenol degradation and the generation and disappearance of the non-biodegradable organic compounds. Removal of phenol and COD were found to follow pseudo first-order kinetics. The removal rate constants for phenol and COD of phenol were $5.204{\times}10^{-1}min^{-1}$ and $3.26{\times}10^{-2}min^{-1}$, respectively.

• Textile Coloration and Finishing
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• v.25 no.3
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• pp.194-205
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• 2013

In this study, we report dyeing properties and functionality of cotton and silk fabrics dyed with methanol extract from Juniperus chinensis heartwood. Non-aqueous dye of Juniperus chinensis heartwood extracted with methanol was expressed reddish color. It showed relatively good affinity to silk than cotton. Dye uptake of cotton and silk continued to increase according to the increase of the dye concentration. Cotton was not affected by the dyeing temperature and time, however, dye uptake of silk was increased as the dyeing time and temperature were increased. Dye uptake of cotton and silk were the highest at pH 8 and pH 6 respectively. Dyed fabrics showed various colors depending on mordant types and mordant concentration. Washing, light and perspiration fastness were not good. However, rubbing and dry cleaning fastness showed relatively good grade. Dyed fabrics of ultraviolet-cut ability and deodorant ability were improved. Also, dyed fabrics showed very good antimicrobial abilities of 99.9%.

• YAKHAK HOEJI
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• v.44 no.5
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• pp.384-390
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• 2000

Metabolism study of the dye, benzidine, was performed by gas chromatography-mass selective detector (GC/MSD) in the urine of rats orally administered 100 mg/kg benzidine. Urine samples were collected in metabolic cages for 0-24, 24-48, and 48-72 hrs. Ten ml of the urine was extracted with XAD-2 resin and the XAD-2 column was eluted with methanol. After evaporation, benzidine and its metabolites were extracted with diethyl ether (for non-conjugated fraction). For conjugated metabolites, $\beta$-glucu-ronidase was added to the aqueous layer that was incubated for 1 hr at 5$0^{\circ}C$ and the aqueous layer was extracted as in non-conjugated fraction. Aliquot of trimethylsilylated derivatives was applied to the GC/MSD. The mutagenicity of benzidine and its acetylated metabolites was tested by histidine/reversion assay. Five metabolites observed and confirmed either by electron impact and chemical ionization modes of the GC/MSD, or authentic compounds were monoacetyl-, diacetyl-, hydroxyacetyl-, hydroxydiacetyl-, and hydroxy-benzidine. Monoacetyl-benzidine was more potent than benzidine in histidine/reversion assay. This data indicates that monoacetylation of benzidine may be one of the metabolites produced in metabolic activation process.