• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3745-3748
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• 2012

This study presents a rapid and simple ${\alpha}$ source preparation method for a radioactive waste sample. The recovery of $^{239}Pu$, $^{232}U$ and $^{243}Am$ using a micro-coprecipitation method was over 95%. The ${\alpha}$-peak resolution of Pu and Am isotopes through the micro-coprecipitation method is enough to discriminate the Pu and Am isotopes from other Pu and Am isotopes. The determination of the Pu and Am isotopes using the micro-coprecipitation method was applied to the radioactive waste sample, so that the activity concentrations of the Pu and Am isotopes using the micro-coprecipitation method in the radioactive waste sample were similar to those using the electrodeposition method.

• Analytical Science and Technology
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• v.19 no.4
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• pp.280-284
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• 2006

The objective of this study is to investigate the removal of heavy metal by using the coprecipitation of barium sulfate. Several parameters governing the efficiency of the coprecipitation method were evaluated by the pH of sample solution, amount of coprecipitant, and addition of sulfide for the removal of As(V), Cd(II), Cr(III), Cr(VI), Cu(II), Hg(II) and Pb(II) metal ions ($10{\mu}g/ml$ each). The coprecipitation was about 80% - 95% only for lead at low pH but under 10% for other ions. The amount of removal was about 95% - 100% for Cd, Hg, Pb, Cu in the all pH range by the addition of sulfide with barium sulfate but As(V) and Cr(III, VI) ions were not affected by the same conditions.

• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.473-478
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• 2007

Antibiotic composite was synthesized by coprecipitation of silver nitrate into hydroxyapatite. Adsorbed amount of silver ion was examined by the variation of concentration of silver nitrate, temperature, pressure and curing time. Optimum condition for silver-hydroxyapatite adsorption could be achieved. Physical and chemical characteristic properties of synthesized silver-hydroxyapatite were tested by ICP-MS, SEM-EDAX, DSC and XRD. Antibiotic properties for gram positive staphylococcus aureus (ATCC 6538) and gram negative escherichia coli (ATCC 25922) were tested by shake flake method.

• Journal of the Korean Ceramic Society
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• v.16 no.3
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• pp.155-163
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• 1979

This study was to explore the characteristics of 6 mole% CaO stabilized $ZrO_2$ prepared by wet chemical methods. The results of the experiments were as follows: 1. The powder calcined at 1000$^{\circ}$-110$0^{\circ}C$ was partly agglomerated. The morphology of agglomerate was spherical of 0.5-1$\mu{m}$ in size for Hot Petroleum Drying Method, chain-like of 1-2$\mu{m}$ for Freeze Drying Method, and irreqular of 2-3$\mu{m}$ for Coprecipitation Method. 2. Optimum calcining conditions for powder prepared by wet chemical methods were found: 110$0^{\circ}C$, 2h in air for Hot Petroleum Drying Method and Freeze Drying Method, and 100$0^{\circ}C$, 2h in air for Coprecipitation Method. 3. When specimen was calcined at 1000$^{\circ}$-110$0^{\circ}C$ in air for 2h and then sintered at 1$600^{\circ}C$ in air for 4h, the specimens prepared by wet chemical methods showed a high sintered density (94% of theoretical density) and a low open porosity (<0.8%); however, the sintered density of the specimen prepared by Oxide Wet Mixing Method was 90%. 4. The amount of cubic phase of sintered body prepared by wet chemical methods was observed to be higher than the one prepared by Oxide Wet Mixing Method. 5. It was found that Hot petroleum Drying Method, Freeze Drying Method and Coprecipitation Method were nearly the same in respect of the results of stabilization grade and sintered density of CaO-stabilized $ZrO_2$.

• Bulletin of the Korean Chemical Society
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• v.29 no.9
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• pp.1827-1830
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• 2008

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3559-3564
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• 2013

Alumina particles were grafted onto the surface of manganese oxide particles via the coprecipitation process using surfactant and cosurfactant. The phase of Mn/Al salts (Phase I) and the phase of precipitation agent (Phase II) were prepared in aqueous surfactant solution, separately. Phase II was added into Phase I and the reaction was performed to form the precursors of composites through hydrogen bonding between $Mn(OH)_2$ and $Al(OH)_3$ prepared by the reaction of Mn/Al salts with the precipitation agent. The alumina-grafted manganese oxide particles were obtained as a final product after calcination. The concentrations of Al salt and surfactant were varied to investigate their effects on the formation and the crystallinity of composites. In addition, the crystal structure of products could be controlled by changing the calcination temperature. Through thermal analyses, it was found that the thermal stability of manganese oxide was improved by the introduction of alumina on its surface.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1512-1514
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• 2005

Catalytic properties of Ni-Zr$O_2$ catalysts prepared by coprecipitation have been studied for the gas-phase hydrogenation of 1,3-butadiene to butenes. The coprecipitation method led to the solid solution of Ni-Zr$O_2$, which contains highly resistant Ni species to thermal reduction with H2. Nickel species of the solid solution were highly dispersed in the ZrO2 lattice, so that the reduced catalysts were selective for hydrogenation of 1,3-butadiene to butenes (99.9%) even in the presence of 1-butene.

• Korean Chemical Engineering Research
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• v.53 no.3
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• pp.372-381
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• 2015

The effect of preparation method on the catalytic activities of the $Ni/Al_2O_3$ catalysts on steam reforming of ethylene glycol was investigated. The catalysts were prepared with various preparation methods such as an incipient wetness impregnation, wet impregnation, and coprecipitation method. In the case of coprecipitation method, various precipitants such as KOH, $K_2CO_3$, and $NH_4OH$ were compared. The prepared catalysts were characterized by using $N_2$ physisorption, inductively coupled plasma-atomic emission spectroscopy, X-ray diffraction, temperatureprogrammed reduction, pulsed $H_2$ chemisorption, temperature-programmed oxidation, scanning electron microscopy, and thermogravimetric analysis. Among the catalysts reduced at 773 K, the $Ni/Al_2O_3$ catalyst prepared by a coprecipitation with KOH or $K_2CO_3$ as precipitants showed the best catalytic performance. The preparation method affected the particle size of Ni, reducibility of nickel oxides, catalytic performance (activity and stability), and types of coke formed during the reaction. The $Ni/Al_2O_3$ catalyst prepared by a coprecipitation with KOH showed the increasing catalytic activity with an increase in the reduction temperature from 773 to 1173 K because of an increase in the reduction degree of Ni oxide species even though the particle size of Ni increased with increasing reduction temperature.

• Journal of the Korean Chemical Society
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• v.62 no.2
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• pp.118-123
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• 2018

The hexagonal tungsten bronze $Cs_xWO_3$ nanoparticle was synthesized by a chemical coprecipitation method of ammonium tungstate and $Cs_2CO_3$ in acidic condition. This synthetic method for cesium tungsten bronze is reported for the first time as far as we know. The synthesized $Cs_xWO_3$ as precipitated showed a weak crystallinity of hexagonal unit cell with a crystallite size of about 4 nm without annealing. When the synthesized $Cs_xWO_3$ was annealed in $N_2$ atmosphere, the crystallinity and crystallite size systematically increased maintaining the typical hexagonal tungsten bronze structure as the annealing temperature increased. The analyzed Cs content in the bronze was about 0.3 vs W, which is very close to the theoretical maximum value, 1/3 in cesium tungsten bronze. According to XPS analysis, the reduced tungsten ions existed as both the forms of $W^{5+}$ and $W^{4+}$ and the contents systematically increased as the annealing temperature increased up to $800^{\circ}C$. The $Cs_xWO_3$ thin films on PET substrate were also prepared by a wet-coating method using the ball-milled solution of the annealed $Cs_xWO_3$ nanoparticles at various temperatures. The near-infrared shielding property of these thin films increased systematically as the annealing temperature increased up to $800^{\circ}C$ as expected with the increased contents of reduced tungsten ions.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.257-257
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• 2003