• Journal of the Korean Applied Science and Technology
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• v.17 no.1
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• pp.49-53
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• 2000

For decompose carbon dioxide, manganese oxide was synthesized with $0.25M-MnSO_{4}{\cdot}nH_{2}O$ and 0.5M-NaOH by coprecipitation. We made magnetite deoxidized manganese oxide by hydrogen reduction for 1hour at $330^{\circ}C$. We investigated characteristics of catalyst, hydrogen reduction degree and decomposition rate of carbon dioxide. The structure of the hausmannite certified spinel type. The specific surface area of synthesized hausmannite and deoxidized hausmannite were $22.36m^{2}/g$, $33.56m^{2}/g$ respectively. The decomposition rate of $CO_{2}$ of deoxidized hausmannite was 57%.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.333-340
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• 2006

A (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst were prepared by co-precipitation method and used for low-temperature selective catalytic reduction (SCR) of $NO_x$ with ammonia in the presence of oxygen. The properties of the catalysts were studied by X-ray diffraction (XRD), temperature programmed reduction (TPR) and scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDS). The experimental results showed that (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst yielded 81% NO conversion at temperature as low as $150^{\circ}C$ and a space velocity of $2,400\;h^{-1}$. Crystalline phase of $Mn_{2}O_3$ was present at ${\ge}\;15%$ Mn on $V_{2}O_{5}/TiO_{2}$. XRD confirmed the presence of manganese oxide ($Mn_{2}O_{3}$) at $2{\theta}=32.978^{\circ}(222)$. The XRD patterns presented of (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ did not show intense or sharp peaks for manganese oxides and vanadia oxides. The TPR profiles of (5 wt.%)Mn-(1 wt.%)$V_{2}O_{5}/TiO_{2}$ catalyst showed main reduction peat of a maximum at $595^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.2
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• pp.198-207
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• 1996

It is well known that drag reduction in single phase liquid flow is affected by polymer material, molecular weight, polymer concentration, pipe diameter, and flow velocity. Drag reduction in two phase flow can be applied to the transport of crude oil, phase change system such as chemical reactor, pool and boiling flow, and to present cavitation which occurs in pump impellers. But the research of drag reduction in two phase flow is not sufficient. The purpose of the present work is to evaluate the drag reduction by measuring pressure drop, void fraction, mean liquid velocity, and turbulent intensity whether polymer is added in the horizontal two phase system or not. Experiment has been conducted in a test section with the inner diameter of 24mm and the length of 1,500mm. The polymer materials used are two kinds of polyacrylamide[PAAM] and co-polymer[A611P]. The polymer concentration was varied with 50, 100 and 200 ppm under the same experimental conditions. Experimental results showed that the drag reduction of co-polymer is higher than that of polyacrylamide. Mean liquid velocities increased as polymer was added, and turbulent intensity decreased inversely near the pipe wall.

• Journal of Powder Materials
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• v.20 no.1
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• pp.53-59
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• 2013

Fe-TiC composite powder was fabricated via two steps. The first step was a high-energy milling of FeO and carbon powders followed by heat treatment for reduction to obtain a (Fe+C) powder mixture. The optimal condition for high-energy milling was 500 rpm for 1h, which had been determined by a series of preliminary experiment. Reduction heat-treatment was carried out at $900^{\circ}C$ for 1h in flowing argon gas atmosphere. Reduced powder mixture was investigated by X-ray Diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM) and Laser Particle Size Analyser (LPSA). The second step was a high-energy milling of (Fe+C) powder mixture and additional $TiH_2$ powder, and subsequent in-situ synthesis of TiC particulate in Fe matrix through a reaction of carbon and Ti. High-energy milling was carried out at 500 rpm for 1 h. Heat treatment for reaction synthesis was carried out at $1000{\sim}1200^{\circ}C$ for 1 h in flowing argon gas atmosphere. X-ray diffraction (XRD) results of the fabricated Fe-TiC composite powder showed that only TiC and Fe phases exist. Results from FE-SEM observation and Energy-Dispersive X-ray Spectros-copy (EDS) revealed that TiC phase exists uniformly dispersed in the Fe matrix in a form of particulate with a size of submicron.

• Journal of the Korean Electrochemical Society
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• v.10 no.3
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• pp.229-232
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• 2007

An amperometric immunosensor for the determination of rabbit IgG is proposed. The immunoassay utilizes a screen-printed carbon electrode on which osmium redox polymer is electrodeposited. This immunoassay detects 0.1 ng/ml of rabbit IgG, which is ${\sim}10^2$ fold higher than the most sensitive enzyme amplified amperometric immunoassay. The assay utilizes a screen-printed carbon electrode which was pre-coated by a co-electrodeposited film of an electron conducting redox hydrogel and a rabbit IgG. The rabbit IgG in the electron conducting film conjugates captures, when present, the anti-rabbit IgG. The captured anti-rabbit-IgG is labeled with horseradish peroxidase (HRP) which catalyzes the two-electron reduction of $H_2O_2$ to water. Because the redox hydrogel electrically connects HRP reaction centers to the electrode, completion of the sandwich converts the film from non-electrocatalytic to electro-catalytic for the reduction of $H_2O_2$ to $H_2O$ when the electrode is poised at 200 mV vs. Ag/AgCl.

• Clean Technology
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• v.22 no.2
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• pp.114-121
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• 2016

In this studies, SCR reaction activity and SO₂ durability enhancement study on manufacturing conditions of the V/TiO₂ catalyst was carried out for the removal of nitrogen oxides generated in the combustion furnace. The catalysts are characterized by XPS, Raman, H₂-TPR and SO₂-TPD. When the vanadium was contained of 2 wt%, it showed excellent SO₂ durability and catalytic activity. and When the tungsten is added as a promotor, the enhancement of reducing ability at a low temperature and reduction of SO₂ adsorption capacity improved the reaction activity and SO₂ durability. V/W/TiO₂ are prepared by the lower pH of vanadium solution, vanadium was highly dispersed on the surface and inhibited the formation of crystalline V₂O₅. in addition, it was confirmed that this catalyst can be used as excellent resistance to high concentration of CO in the combustion furnace.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.4
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• pp.282-285
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• 2004

Kinetics of H-spillover over $Pt/MoO_3$ was greatly affected by the amount of residual chlorine differing by calcination temperature. Multifacetted techniques for characterization were dedicated to elucidate the faster reduction of chlorine in the isothermal reduction (ITR) at $50^circ{C}$ after calcination. Reduction of residual chlorine over Platinum resulted in opening the more channel of hydrogen pathway into more $MoO_3$ particles and controlling the kinetics of hydrogen uptake.

• Journal of Animal Science and Technology
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• v.60 no.11
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• pp.27.1-27.8
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• 2018

Background: Enteric methane ($CH_4$) accounts for about 70% of total $CH_4$ emissions from the ruminant animals. Researchers are exploring ways to mitigate enteric $CH_4$ emissions from ruminants. Recently, nano zinc oxide (nZnO) has shown potential in reducing $CH_4$ and hydrogen sulfide ($H_2S$) production from the liquid manure under anaerobic storage conditions. Four different levels of nZnO and two types of feed were mixed with rumen fluid to investigate the efficacy of nZnO in mitigating gaseous production. Methods: All experiments with four replicates were conducted in batches in 250 mL glass bottles paired with the ANKOM$^{RF}$ wireless gas production monitoring system. Gas production was monitored continuously for 72 h at a constant temperature of $39{\pm}1^{\circ}C$ in a water bath. Headspace gas samples were collected using gas-tight syringes from the Tedlar bags connected to the glass bottles and analyzed for greenhouse gases ($CH_4$ and carbon dioxide-$CO_2$) and $H_2S$ concentrations. $CH_4$ and $CO_2$ gas concentrations were analyzed using an SRI-8610 Gas Chromatograph and $H_2S$ concentrations were measured using a Jerome 631X meter. At the same time, substrate (i.e. mixed rumen fluid+ NP treatment+ feed composite) samples were collected from the glass bottles at the beginning and at the end of an experiment for bacterial counts, and volatile fatty acids (VFAs) analysis. Results: Compared to the control treatment the $H_2S$ and GHGs concentration reduction after 72 h of the tested nZnO levels varied between 4.89 to 53.65%. Additionally, 0.47 to 22.21% microbial population reduction was observed from the applied nZnO treatments. Application of nZnO at a rate of $1000{\mu}g\;g^{-1}$ have exhibited the highest amount of concentration reductions for all three gases and microbial population. Conclusion: Results suggest that both 500 and $1000{\mu}g\;g^{-1}$ nZnO application levels have the potential to reduce GHG and $H_2S$ concentrations.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.462-469
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• 1993

The electrocatalytic reduction of dioxygen is investigated by cyclic voltammetry and chronoamperometry at glassy carbon electrode and carbon microelectrode coated with a variety of cobalt phenylporphyrins. The n value obtained at carbon microelectrode is slightly different from that determined at glassy carbon electrode. Dioxygen reduction catalyzed by the monormeric porphyrin Co(II)-TPP mainly occurs through the $2e^-$ reduction pathway resulting in the formation of hydrogen peroxide, electrocatalytic process carries out $4e^-$ reduction pathway of dioxygen to $H_2O$ at the electrodes coated with bis-cobalt phenylporphyrins. The electrocatalytic reduction of dioxygen is irreversible and diffusion controlled.

• Bulletin of the Korean Chemical Society
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• v.34 no.8
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• pp.2461-2465
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• 2013

Pd-$Ce/{\gamma}-Al_2O_3-TiO_2$ catalysts were prepared by combined sol-gel and impregnation methods. Transmission electron microscopy, X-ray diffraction, $H_2$-temperature-programmed reduction, $O_2$-temperature-programmed desorption, and ethanol oxidation experiments were conducted to determine the properties of the catalysts. Addition of an optimal amount of Ce improved the performance of the $Pd/{\gamma}-Al_2O_3-TiO_2$ catalyst in promoting the complete oxidation of ethanol. The catalyst with 1% Ce exhibited the highest activity, and catalyzed complete oxidation of ethanol at $175^{\circ}C$; its selectivity to $CO_2$ reached 87%. Characterization results show that addition of appropriate amount of Ce could enrich the PdO species, and weaken the Pd-O bonds, thus enhancing oxidation ability of the catalyst. Meanwhile, the introduction of $CeO_2$ could make PdO better dispersed on ${\gamma}-Al_2O_3-TiO_2$, which is beneficial for the improvement of the catalytic oxidation activity.