• Economic and Environmental Geology
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• v.43 no.3
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• pp.269-278
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• 2010

We investigated characteristics of the coloring material of Dancheong pigments and hope that this study contributes the revival of traditional Dancheong pigments color. For this purpose, we collected Dancheong fragment samples that fell off naturally from old wooden buildings in Gwangju and Jeonnam and analyzed the natural coloring material by XRD and EDS-SEM analysis method. In white pigments of Dancheong fragments, it is confirmed that gypsum$(CaSO_{4}{\cdot}2H_{2}O)$, quartz$(SiO_{2})$, white lead$(PbCO_{3})$ and calcite$(CaCO_{3})$ which have been used for white pigments since ancient times and $TiO_{2}$ which is common used in modern times. In red pigments of Dancheong fragments, it is confirmed that hematite$(Fe_{2}O_{3})$ and red lead$(Pb_{3}O_{4})$, which have been used for red pigments since ancient times and C.I. pigment orange $13(C_{32}H_{24}C_{12}N_{8}O_{2})$ but there is no cinnabar(HgS) which has been used since B.C. 3000 in China. In yellow pigments of Dancheong fragments, it is confirmed that crocoite$(PbCrO_{4})$ and massicot(PbO). In blue pigments of Dancheong fragments, it is confirmed that sodalite$(Na_{4}BeAlSi_{4}O_{12}Cl)$ and nosean $(Na_{8}Al_{6}Si_{6}O_{24}SO_{4})$ as coloring material of blue pigment and C.I. pigments blue $29(Na_{7}Al_{6}Si_{6}O_{24}S_{3})$ which is used in modern times. In green pigments of Dancheong fragments, it is confirmed that calumetite$(Cu(OHCI)_{2}{\cdot}2H_{2}O)$, escolaite(Cr2O3), dichromium trioxide$(Cr_{2}O_{3})$, emerald green$(C_{2}H_{3}As_{3}Cu_{2}O_{8})$, and C.I. pigments green$(C_{32}H_{16}-XCl_{x}Cu_{8})$ which is used in modern time. In black pigments of Dancheong fragments, Chiness ink(carbon black) is confirmed.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.275-282
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• 2010

A characteristic study of aqueous chlorine dioxide generation from sodium chlorite($NaClO_2$) by an undivided electrochemical cell with different anode materials were performed. $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA were used as anode materials and Pt-coated Ti electrode was used as cathode. Various electrochemical cell operating parameters such as cell residence time($t_R$), initial feed solution pH, sodium chlorite and sodium chloride(NaCl) concentration and applied current for the generation of chlorine dioxide in an un-divided cell were investigated and optimized. Estimated optimal cell residence times in $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode material systems were around 2.27, 1.52 and 1.52 sec, respectively. Observed optimum initial feed solution pH was around 2.3 in all anode material systems. Optimum sodium chlorite concentrations in $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode systems were around 0.43, 0.43 and 0.32 g/L, respectively. Optimum electrolyte concentration and applied current were around 5.85 g/L and 0.6 A in all anode systems. Current efficiencies of $IrO_2$-coated Ti, $RuO_2$-coated Ti and DSA anode systems under optimum conditions were 79.80, 114.70 and 70.99%, respectively. Obtained energy consumptions for the optimum generation of chlorine dioxide were 1.38, 1.03 and $1.61W{\cdot}hr/g-ClO_2$, respectively.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.530-534
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• 2011

The synthesis of dimethyl carbonate by liquid phase oxidative carbonylation of methanol was studied under batch reaction system. Reaction factors such as effect on various metals, anion containing in copper catalyst, temperature, carbon monoxide and oxygen molar ratio and copper content were investigated. In particular $CuCl_2{\cdot}2H_2O$ showed the excellent of the methanol conversion 65.2%, DMC selectivity 96.6% reaction condition under 1.0 g, $150^{\circ}C$, MeOH/CO/$O_2$=0.2/0.215/0.05 (molar ratio). $CuCl_2$ led to corrosion of the reactor. Thus, a new catalyst system using supports was investigated to resolve these corrosion problem. Influence on various supports were examined and copper catalyst supported on zeolite Y showed the most excellent activity on the formation of dimethyl carbonate. The amount of Fe dissolved during the reaction using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometer) was compared with catalysts, calcined Cu/zeolite Y showed the lower value below 5% than $CuCl_2-2H_2O$.

• Korean Journal of Crystallography
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• v.18 no.1_2
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• pp.21-25
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• 2007

When a $CH_2Cl_2$ solution of the dipyridyl species L' (N,N'-bis-(1-pyridin-4-yl-ethylidene)-naphthalene-1,5-diamine) was layered onto the top of a MeOH solution of $Co(NO_3)_2{\cdot}6H_2O$, a molecular cobalt compound [$CoL_2(MeOH)(NO_3)_2$] (1), not a coordination polymer, was formed. X-ray structural analysis of compound 1 revealed that it contains the pyridyl-amine ligand L (N1-(4-imino-1-methyl-but-2-enylidene)-naphthalene-1,5-diamine), instead of L'. Structure of compound 1 strongly suggests that the original ligand L' has been hydrolyzed to ligand L during the reaction.

• Korean Journal of Materials Research
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• v.23 no.11
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• pp.661-665
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• 2013

We investigated the characteristics of electroless plated Cu films on screen printed Ag/Anodized Al substrate. Cu plating was attempted using neutral electroless plating processes to minimize damage of the anodized Al substrate; this method used sodium hypophosphite instead of formaldehyde as a reducing agent. The basic electroless solution consisted of $CuSO_4{\cdot}5H_2O$ as the main metal source, $NaH_2PO_2{\cdot}H_2O$ as the reducing agent, $C_6H_5Na_3O_7{\cdot}2H_2O$ and $NH_4Cl$ as the complex agents, and $NiSO_4{\cdot}6H_2O$ as the catalyser for the oxidation of the reducing agent, dissolved in deionized water. The pH of the Cu plating solutions was adjusted using $NH_4OH$. According to the variation of pH in the range of 6.5~8, the electroless plated Cu films were coated on screen printed Ag pattern/anodized Al/Al at $70^{\circ}C$. We investigated the surface morphology change of the Cu films using FE-SEM (Field Emission Scanning Electron Microscopy). The chemical composition of the Cu film was determined using XPS (X-ray Photoelectron Spectroscopy). The crystal structures of the Cu films were investigated using XRD (X-ray Diffraction). Using electroless plating at pH 7, the structures of the plated Cu-rich films were typical fcc-Cu; however, a slight Ni component was co-deposited. Finally, we found that the formation of Cu film plated selectively on PCB without any lithography is possible using a neutral electroless plating process.

• KSBB Journal
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• v.6 no.2
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• pp.207-213
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• 1991

In this study poly (1-methyl-4-vinylpyridinium iodide-co-styrene) membrane with pyridinium cation as a fixed carrier was synthesized and the transport characteristics of the membrane was examined over various factors. As the concentration of the fixed carrier in the membrane was increased, the water content was increased. Meanwhile, the counter current of the organic anion and the chloride ion, the following results were obtained. Initial flux of Cl-, organic anion and Na+ decreased with the increasing thickness of membrane, and as the concentration of the fixed carrier increases, the initial flux of Cl- and organic anion increase but the initial flux of Na+ decreased. The flux equation of the organic anion, CCl3COO- was obtained from saturation kinetics as follows;$V_{o}=\frac{(8.67{\times}10^{-5}){\cdot}[NaCl]}{9.63{\times}10^{-2}+[NaCl]} mol/cm^2h$

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.313-319
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• 2007

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were $H_3PO_4,\;CaCl_2,H_3BO_3$, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The optimal concentrations for higher production of biosurfactants were (g/l): glucose, $1.1;NaNO_3,\;4.4;MgSO_4{\cdot}7H_2O,\;0.8;KCl,\;0.4;CaCl_2,\;0.27;H_3PO_4,\;1.0ml/l;\;and\;trace elements\;(mg/l):H_3BO_3,\;0.25;CuSO_4,\;0.6;MnSO_4,\;2.2;Na_{2}MoO_4,\;0.5;ZnSO_4,\;6.0;FeSO_4,\;8.0;CoCL_2,\;1.0;$ and Na-EDTA, 30.0. Using this statistical optimization method, the relative biosurfactant yield as critical micelle dilution (CMD) was increased from $10{\times}\;to\;105{\times}$, which is ten times higher than the non-optimized rich medium.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.75-81
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• 1997

Streptomyces chibaensis J-59 did not grow in the culture medium containing only xylose or xylan as a carbon source, because it was defective in xylulokinase production; xylB mutant. S. chibaensis J-59 was able to produce xylanase and $\beta $-xylosidase as well as glucose isomerase. The glucose isomerase in S. chilbaensis J-59 was induced in the medium containing xylan or xylose which could be utilized as an inducer but not sa carbon and energy sources. So we tried to produce glucose isomerase whthout consumption of xylose or xylan as an inducer by using xylB mutant S. chilbaensis J-59. The optimum condition for the production of the glucose isomerase was attained in a culture medium composed of 1% xylan, 0.15% glucose, 1.5% corn steep liquor, 0.1% MaSO$_{4}$ $\CDOT $7H$_{2}$O, and 0.012% CoCL$_{2}$ $\CDOT $ 6H$_{2}$O(pH 7.0). The production of the enzyme reached to a maximum level when the bacteria were cultured for 42 h at 30$\circ $C. The enzyme production in a jar fermentor was increased twice as much as that in a flask culture.

• Journal of environmental and Sanitary engineering
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• v.17 no.1
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• pp.12-19
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• 2002

This study was carried out to investigate the optimal condition for granite particle coagulation process by using various chemical coagulation agents. The coagulation of a suspended granite particle was monitored by using various different coagulants, such as $Al_2(SO_4)_3{\cdot}14H_2O,{\;}FeCl_3{\cdot}6H_2O,{\;}SA-solution(KOH{\;}+{\;}Al(OH)_3{\;}+{\;}K_2CO_3{\;}mixture)$ and jade particle. To accomplish this study, analysis of water quality, removing Turbidity and Packing Density were measured with jar-tester. In the results of this experiment, it was found that the removal rate of the granite particle was increased with the decrease of the pH of the sludge. The turbidity(NTU) at the above coagulants was reduced from 95% to 98%. Removed of Turbidity and Packing Density was more efficiency to the SA-solution than others.

• Current Research on Agriculture and Life Sciences
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• v.14
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• pp.101-110
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• 1996

Using response surface methodology(RSM), the various conditions(agitation speed, air flow, glucose concentration) in jar fermentor culture were investigated to find the optimum conditions for maximum enzyme production. Central-composite-design was used to control the variable constant in the experiment. The glucose isomerase production of Steptomyces chibaensis J-59 was mostly affected by the air flow rate and glucose concentration. The estimated optimum conditions were as follows: 1% birchwood xylan, 1.5% CSL, 0.1% $MgSO_4{\cdot}7H_2O$, 0.012% $CoCl_2{\cdot}6H_2O$, pH 7.0; air flow, 2.2vvm; agitation speed, 587rpm; glucose concentration, 0.586%. Experimental values(7.43GIU/ml) for the enzyme production obtained from the given optimum conditions had a almost resemblane to response values(7.67GIU/ml) predicted by the RSM. The jar fermentor culture by the RSM produced xylose isomerase about 2.7 times as much as the baffled flask culture.