• Applied Biological Chemistry
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• v.48 no.2
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• pp.155-160
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• 2005

Electrolyzed reduced water (ERW), showing extremely negative oxidation-reduction potential, was used to investigate the effects of paraquat-induced damages on DNA from human lymphocyte. The effect of ERW on paraquat-induced oxidative DNA damage in human lymphocytes was evaluated by Comet assay (single-cell gel electrophoresis) quantified as percentage fluorescence in tail. Comet assay has been used widely to assess the level of the DNA damage in individual cells. Lymphocytes were oxidatively challenged with various concentrations of paraquat for 30 min at $37^{\circ}C$, and were then treated with electrolyzed reduced water for 30 min. The oxidative DNA damage by paraquat, as indicated by the fluorescent tail in DNA, increased in a dose-dependent manner. However, oxidative damage of the DNA was almost completely prevented upon treatment with electrolyzed reduced water.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.191-200
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• 2014

Gas hydrates play a significant role in the global carbon cycle and climate change because methane, a greenhouse gas, can be released from the dissociation of gas hydrate. Anaerobic oxidation of methane (AOM) is an important process that consumes more than 90% of the methane released into the hydrosphere and atmosphere. In this study, the microbial community associated with the methane gas hydrate sediment in the Ulleung basin, East Sea of Korea (UBGH) was analyzed by phylogenetic analysis of the mcrA and 16S rRNA gene libraries. A vertical stratification of the dominating anaerobic methane oxidizer (ANME)-1 group was observed at the surface and the sulfate methane transition zone (SMTZ). The ANME-2c group was found to be dominant in the high methane layer. The archaea of marine benthic group B, which is commonly observed in the AOM region, accounted for more than 50% of the identifications in all sediments. Nitrate reducing bacteria were predominant at SMTZ (Halomonas: 56.5%) and high methane layer (Achromobacter: 52.6%), while sulfate reducing bacteria were not found in UBGH sediments. These results suggest that the AOM process may be carried out by a syntrophic consortium of ANME and nitrate reducing bacteria in the gas hydrates of the Ulleung Basin of the East Sea.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.335-344
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• 2006

In this paper a computer program was developed, which simulates the Li reduction process of PWR spent fuel, and the amount of a produced metal or chloride compound was calculated at the various amount of Li with the program. It establishes a database, which is composed of some characteristics related to a chemical reaction equation and thermodynamic data, and it calculates the transformed rate of PWR spent fuel oxide at the certain amount of Li by using the database as input data. As the results of the performance test of the program, it was validated that the transformed values of oxides, except for $Eu_2O_3$ and $Sm_2O_3$, were almost the same to within about a 6 % error with those calculated by the previous code and that the calculated amount of Li was also exactly consistent with the theoretical one, which is used for a complete reaction of each oxide in a single chemical reaction. A relationship between Li and the transformed metal of each oxide was analyzed on the basis of the quantities calculated with the verified development program. Of the results, when the amount of Li was given to be 250 mole, the 83.73 percentage of $UO_2$ was transformed into U while the remainder was still to be $UO_2$. In addition, it was appeared that the 297 mole of Li was needed to completely convert $UO_2$ into U.

• Journal of Hydrogen and New Energy
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• v.19 no.3
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• pp.189-198
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• 2008

Cooperative effects of Rh, Ce and Zr added to Fe-based oxide mediums were investigated using temperature programmed redox reaction (TPR/TPO) and isothermal redox reaction in the view point of hydrogen storage and release. As the results of TPR/TPO, Rh was a sale additive to remarkably promote the redox reaction on the medium as evidenced by the lower highest peak temperature, even though its addition was to accelerate deactivation of the mediums due to sintering. On the other hand, Ce and Zr additives played an important role to suppress deactivation of the medium in repeated redox cycles. The medium co-added by Rh, Ce and Zr (FRCZ) exhibited synergistic performance in the repeated isothermal redox reaction, and the amount of hydrogen produced in the water splitting step at 623 K was highly maintained at ca. $17\;mmol{\cdot}g^{-1}-Fe$ during three repeated redox cycles.

• Applied Chemistry for Engineering
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• v.28 no.3
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• pp.279-285
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• 2017

In this study, the study of the selective catalytic oxidation (SCO) for controlling the $NH_3$ at $200{\sim}350^{\circ}C$ range was investigated. Physicochemical properties of the catalysts were determined using XRD and XPS analysis. In the case of catalytic activity according to thermal treatment condition, the reduction catalyst showed better activity than that of using the calcination catalyst. It was confirmed that the valence state of reduction catalyst was mainly $Pt^{2+}$ and $Pt^0$ as analyzed by XPS. Also, when comparing the reaction activities of $Pt/TiO_2$ catalysts according to the reduction temperature, the $NH_3$ conversion of the catalyst reduced at $700^{\circ}C$ showed the most excellent activity. However, the best activity of $NH_3$ conversion to $N_2$ was obtained for the catalyst reduced at $600^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.74-78
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• 2002

In this study, the solution combustion method was employed to synthesize perovskite PZT ceramics. Multicomponent oxides can be prepared by the solution combustion synthesis using redox exothermic reaction of precursor solutions. The results of DTA/TG showed exothermic peaks in 214$^{\circ}C$ and 350$^{\circ}C$. Those were caused by the differences of the thermal decomposition behavior of oxidizer and fuel. The combustion reaction was completed at 370$^{\circ}C$ during heating procedure, but the product was not transformed into perovskite. The thermal decomposition behavior of both oxidizer and fuel were considered during solution combustion process at 600$^{\circ}C$, which showed tetragonal single phase PZT ceramics with 50 nm crystalline size. The lattice constant a was 3.997 ${\pm}$ 0.001 ${\AA}$ and the lattice constant c was 4.147${\pm}$0.001 ${\AA}$.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.229-232
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• 2009

We prepared gold nanoparticles (Au NPs) by reduction-oxidation reaction between $HAuCl_4$ and trisodium citrate and measured the size and morphology of Au NPs by TEM for various molar ratios of $HAuCl_4$ to citrate and for various concentrations of $HAuCl_4$. UV-vis spectroscopy was used to characterize the optical properties of Au NPs. Au NPs in the size range from 14.3 nm to 20.3 nm were prepared with monodisperse distribution.

• Resources Recycling
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• v.31 no.6
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• pp.18-24
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• 2022

Dry reduction using natural gas was proposed to recover tin from waste tin oxide generated in a tin bath that was used for controlling the smoothness of architectural glass during production, and the reduction behavior was investigated. The utilized vertical natural gas dry reduction system is capable to process 4 L or 20 kg depending on input raw materials. The system was established by applying the upper intake and lower discharge method. The recovery rate was 97.2% at 800 ℃ and 4 sccm flow rate and increased with the amount of input gas. Hydrogen accounted for 23% of the discharge gas, showing a 16.6% hydrogen conversion rate. The reaction behavior of tin recovered via natural gas reduction provides basic data on the new waste resource reduction/recovery technology.

• Journal of the Mineralogical Society of Korea
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• v.25 no.3
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• pp.155-162
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• 2012

We observed characteristic oxidation and dissolution phenomena induced by dissolved oxygen for mackinawite that is produced via sulfate-reducing bacteria (SRB) living in anaerobic environments such as soils and groundwater. We tried to recognize the role of the sulfide minerals that usually coexist with some stabilized radionuclides (e.g., reduced uranium), which can be reoxidized and redissolved by an oxygen-rich groundwater invaded into a contaminated area. The mackinawite produced by 'Desulfovibrio desulfuricans', a sulfate-reducing bacterium, was conducted to be dissolved for 2 weeks by some oxidants such as 'hydrogen peroxide' and 'sodium nitrite'. Although mineralogical oxidation and dissolution characteristics were different from each other according to the oxidants, the initially oxidized solution was early stabilized through the oxygen consumption by ${\mu}m$-sized sulfide particles and the resultant increase of sulfate in solution. From these results, we can anticipate that the large amount of sulfide minerals generated by SRB can not only repress the anoxic environment to be disturbed by the consumption of oxygen in groundwater, but also contribute to stabilize the reduced/precipitated radionuclides as a buffer material for a long time.

• Journal of the Mineralogical Society of Korea
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• v.22 no.2
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• pp.107-114
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• 2009

In present study, an alternative process for manufacturing ultra marine blue by using kaolin, sulfur, sodium carbonate, silica, and rosin was investigated. From the experiments, it was found in the reductive calcination process that the temperature variation with the bed height of input materials is relatively high due to the inadequate thermal conductivity of them. It was also found that the color of the ultramarine blue manufactured is sensitive for the shape of the input materials and the calcinations conditions, and specially the heating rate is very important to form ultramarine. For manufacturing green ultramarine by using sulfur, sodium carbonate, silicon, and pine resin, an optimum condition was investigated to be the heating rate region below $0.6^{\circ}C/min$, the reaction temperature of $850^{\circ}C$ and the reaction time of 4 hr. At the oxidative calcination process to manufacture ultra marine blue from green ultramarine, the optimum flow rate of air is $500{\sim}550\;{\ell}/kg$ (green ultramarine) and the reaction temperature is $500{\sim}550^{\circ}C$.