• Bulletin of the Korean Chemical Society
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• v.32 no.9
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• pp.3209-3210
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• 2011

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.773-781
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• 2004

Ceramic foams prepared from silica -clay were coated with TiO$_2$ and V$_2$O$_{5}$ catalysts for selective catalytic reduction of NOx with NH$_3$. The effects of V$_2$O$_{5}$ loading, reaction temperature, space velocity, and oxygen content on NOx reduction with NH$_3$ were mainly investigated. Also, the NOx reduction characteristics of V$_2$O$_{5}$ and V$_2$O$_{5}$ -TiO$_2$ filters were compared when sulfur dioxide exists. From the results, the optimal NOx reduction with the maximum reduction efficiency of 91 % could be performed under the condition with V$_2$O$_{5}$ loading 6.0 wt. %, reaction temperature 35$0^{\circ}C$, space velocity 6,000h$^{-1}$ , and oxygen content 5%. And, the V$_2$O$_{5}$ -TiO$_2$ filters have shown higher NOx reduction efficiency and acid resistance against sulfur dioxide than the V$_2$O$_{5}$ filters.

• Journal of Soil and Groundwater Environment
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• v.14 no.6
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• pp.29-34
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• 2009

In this study, a chloride ion probe as a direct measurement for perchlorate reduction was used to determine whether biological perchlorate reduction was inhibited by other electron acceptors ($O_2$ and ${NO_3}^-$) and to investigate competition of electron acceptors for using electron donors. Profiles of chloride production (= perchlorate reduction) in flasks containing perchlorate reducing populations were monitored by a chloride ion probe. Biological reduction of 2 mM perchlorate was inhibited by 2 mM nitrate that chloride production rate was decreased by 30% compared to perchlorate used as the only electron acceptor and chloride production rate was decreased by 70% when acetate was limited. Reduction of 2mM perchlorate was completely inhibited by oxygen at 7~8 mg/L, regardless of acetate excess / limitation.

• Journal of Powder Materials
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• v.20 no.1
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• pp.43-47
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• 2013

The extraction of metallic pure vanadium powder from raw oxide has been tried by Mg-reduction. In first stage, $V_2O_5$ powders as initial raw material was reduced by hydrogen gas into $V_2O_3$ phase. $V_2O_3$ powder was reduced in next stage by magnesium gas at 1,073K for 24 hours. After reduction reaction, the MgO component mixed with reduced vanadium powder were dissolved and removed fully in 10% HCl solution for 5 hours at room temperature. The oxygen content and particle size of finally produced vanadium powders were 0.84 wt% and 1 ${\mu}m$, respectively

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.527-530
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• 2002

A lot of efforts have been focused on the optimization of PIT parameters for Bi-2223/Ag wire. In this paper, initial annealing of Bi-2223/Ag wire to transform Bi-2212 orthorhombic from Bi-2212 tetragonal Precursor was investigated. This initial annealing step at low oxygen partial pressure were to transform Bi-2212 orthorhombic structure and to reduce the formation of second phases at superconducting wire. However Bi-2223 Phases were appeared at higher annealing temperature. Critical currents(Je) of Bi-2223/Ag tapes were sintered at low oxygen Partial pressure were higher than that of the wires sintered at atmosphere condition. In order to investigate the effect of rolling reduction ratio, Bi-2223/Ag HTS tapes were rolled with different reduction ratio. There were no clear difference of Je and filaments shape with various rolling reduction ratio.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.241-246
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• 2003

Numerical simulations are performed at atmospheric pressure in order to understand the effect of additives on flame speed and the NOx formation in freely propagating $H_{2}/O_{2}/N_{2}$ flames with oxygen enrichments. A chemical kinetic mechanism is developed, which involves 26 gas-phase species and 99 reactions. Under several equivalence ratios and oxygen enrichments, flame speeds are calculated and compared with those obtained from the experiments, the results of which is in good agreement. As hydrogen chloride as additive is added into $H_{2}/O_{2}/N_{2}$ flames with low oxygen enrichments, its chemical effect causes the decrease of flame speed, radical concentration, and the NO production rate. It is found that the chemical effect of additive has much more influence on the reduction of EINO than its physical effect. However, in flames with very high flame temperature the physical effect rather than the chemical effect becomes more important on the reduction of EINO.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.22-27
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• 2011

Purpose: Packing the nose is a common procedure after the closed reduction of a nasal bone fracture to prevent postoperative complications, such as bleeding and adhesion formation as well as to stabilize the framework of the nasal bone. On the other hand, it is difficult for a patient to endure nasal packing because of breathing difficulties, headaches, chest discomfort, insomnia, general weakness and hypoxia. This study examined the availability of a bronchodilator to improve the decreased oxygen saturation and postoperative symptoms on nasal packing. Methods: From February, 2010 to July, 2010, a prospective randomized comparison of the incidence of a range of postoperative signs and symptoms was conducted on 60 patients, who did (n=30) and did not (n=30) undergo bronchodilator infusion (aminophylline 250 mg/10 mL + normal saline 100 mL IV qd) following nasal packing. The postoperative symptoms and oxygen saturation in the two groups were compared. Results: Patients who had infused the bronchodilator showed improved oxygen saturation. Nevertheless, there were no significant differences in the postoperative uncomfortable symptoms (dyspnea, headache, chest discomfort, insomnia, general weakness) between the two groups. Conclusion: A bronchodilator after nasal packing improves oxygen saturation by dilating the airway tract but it cannot reduce the uncomfortable symptoms caused by nasal obstruction. Overall, the bronchodilator is a useful medication for improving the level of oxygen saturation.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.4
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• pp.201-208
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• 2000

The reduction of NO by hydrocarbons was investigated over Cu/Al$_2$O$_3$catalysts using a stainless steel flow reactor under highly oxidising diesel exhaust conditions(up to 15%). Three different Cu loadings(1,5 and 10wt.%) on an $Al_2$O$_3$support were prepared and characterized using spectroscopic techniques. The catalytic activity tests show that different Cu loadings as well as temperature, oxygen, and hydrocarbon concentration levels significantly influence the NO reduction. Increasing Cu loadings up to 5 and 10wt.% decreases the catalytic activities for NO reduction due to the formation of a bulk crystalline CuO phase, as observed from XRD and SEM images. In particular, the visualization of the copper dispersion on the surface using the SEM-BEI technique provides information on the extent of copper saturation, particle size, and the effects on NO reduction. However, the lower Cu loading(1 wt.%) increases the catalytic activity with a temperature window of 720-810K, thereby favoring the formation of well dispersed isolated Cu species, e.g. Cu(sup)2+ ions, which is related to selective NO reduction. The effects of other reaction parameters, such as oxygen, the hydrocarbon level and type, and byproduct emissions are further discussed.

• Journal of the Semiconductor & Display Technology
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• v.15 no.1
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• pp.70-75
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• 2016

GZO films prepared on ITO glasses were annealed at various temperatures in a vacuum condition to research the relationship between oxygen vacancies and optical properties. GZO films after annealing in a vacuum showed the various optical-chemical properties depending on the annealing temperatures and oxygen gas flow rate during the deposition. The oxygen vacancy of GZO film prepared by oxygen gas flows of 22 sccm increased with increasing the annealing temperatures, because of the extraction of oxygen by the annealing. But the intensity of photoluminance of GZO with 22 sccm decreased in accordance with the annealing temperature, because of the reduction of ionized charge carriers. The oxygen vacancy by the extraction of oxygen enhanced a depletion, so the widen depletion had the strong Schottky barrier and the PL intensity due to the low carrier density decreased.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.543-553
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• 1996

Oxygen reduction in an alkaline fuel cell was studied by using perovskite type oxides as an oxygen electrode catalyst. The high surface area catalysts were prepared by malic acid method and had a formula of $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35 and 0.50). From the result of XRD pattern and specific surface area due to the amount of Fe substitution and the consumption of ammonia-water, the complex formation of Fe ion with $NH_3$ was the main factor for both the phase stability of perovskite and the increase of specific surface area. Multi-step calcination was necessary to give a single phase of perovskite in catalyst precursor. The crystal structure of the catalysts was simple cubic perovskite, which was verified from the XRD patterns of the catalysts. The activity of oxygen reduction was monitored by the techniques of cyclic voltammetry, static voltage-current method, and current interruption method. The activity(current density) of oxygen reduction showed its minimum at x=0.01 and its maximum between 0.20 and 0.35 of x-value in $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$. This tendency was independent of the change of surface area.