• Economic and Environmental Geology
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• v.29 no.2
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• pp.207-214
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• 1996

For many years oxygen and hydrogen isotope analysis have been used as one of the most valuable research tools to investigate many geological processes. There are many sample preparation techniques of oxygen and hydrogen isotope analysis for various geological samples. We introduce here several important sample preparation techniques for oxygen and hydrogen isotope analysis and discuss the problems of each method in detail.

• Journal of the Korean Ceramic Society
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• v.49 no.1
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• pp.29-36
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• 2012

In many applications of functional oxides originally homogeneous materials are exposed to gradients in the chemical potential of oxygen. Prominent examples are solid oxide fuel cells (SOFCs) or oxygen permeation membranes (OPMs). Other thermodynamic potential gradients are gradients of electrical potential, temperature or uni-axial pressure. The applied gradients act as generalized thermodynamic forces and induce directed fluxes of the mobile components. These fluxes may lead to three basic degradation phenomena of the materials, which are kinetic demixing, kinetic decomposition, and morphological instabilities.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.256-260
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• 2003

A computer program to calculate thermodynamic properties of oxygen is developed. Procedures for the calculation is briefly discussed. The program calculates unknown thermodynamic properties fixing the state with two independent input properties. If input value by user is inappropriate, it displays an error message. In addition user can change units with easy. The program developed in this work can be utilized to calculate parameters required for the simulation and design of an equipment using oxygen.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.369-373
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• 2002

The liquid phase oxidation of p-xylene has been carried out with oxygen-enriched gas, and the manganese component was precipitated probably via over-oxidation to $Mn^{4+}$. The precipitation increased with rising oxygen concentration in the reaction gas and occurred mainly in the later part of the oxidation. The activity of the reaction decreased, and the blackening of the product and side reactions to carbon dioxide increased with the degree of precipitation. Precipitation can be decreased with the addition of metal ions, such as cerium, chromium and iron.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.119-125
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• 1996

The experimental work is performed to obtain content levels and characteristics of flue gas in infrared mobile heaters for butane gas with varying the chamber size and its room temperature. The results showed that the oxygen depletion sensor device is operated at 18.3% of oxygen content. And the relation of oxygen content and carbon dioxide content in an enclosed space show linear aspect, but the content rate of carbon monoxide occurs at random without the level of oxygen content and carbon dioxide content.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.101-101
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• 2008

The effect of oxygen partial pressure on the surface tension data of liquid alloys was investigated by means of comparing the calculated data and the measured one. Two binary alloy systems were chosen to observe the dependence of oxygen adsorption behavior on different oxygen partial pressures. It was found that the difference between the computed values and the experimental of the surface tension was within the range of maximum 10%.

• Bulletin of the Korean Chemical Society
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• v.6 no.2
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• pp.115-118
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• 1985

The oxidation of hydrazobenzene by oxygen in methanol solution is catalysed by Co(3MeOsalen) which is a synthetic oxygen carrier. The products are trans-azobenzene and water. The rate of the reaction has been studied spectrophotometrically and the rate law established. A mechanism involving a ternary complex of catalyst, hydrazobenzene and oxygen has been proposed.

• Journal of Embryo Transfer
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• v.24 no.3
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• pp.231-235
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• 2009

Oxygen consumption has been regarded as a useful indicator for assessment of mammalian embryo quality. However, there was no standard criterion to measure the oxygen consumption of embryos. Here, we measured oxygen consumption of bovine embryos at various developmental stages was measured using a scanning electrochemical microscopy (SECM). We found that the oxygen consumption significantly increased in blastocyst-stage embryos compared to other stage embryos (from 2-cell-stage to morula-stage), indicating that oxygen consumption reflects the cell number ($5.2{\sim}7.6{\times}10^{14}/mol\;s^{-1}$ versus $1.2{\sim}2.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). In the morula-stage embryos, the oxygen consumption of in vivo derived embryos was significantly higher than that of in vitro produced embryos ($4.0{\times}10^{14}/mol\;s^{-1}$ versus $2.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). However, there was no significant difference in consumption of oxygen by in vivo and in vitro-derived bovine blastocyst-stage embryos (p>0.05). In the frozen-thawed blastocyst-stage embryos, live embryos showed significantly higher oxygen consumption than dead embryos ($4.7{\times}10^{14}/mol\;s^{-1}$ versus $1.0{\times}10^{14}/mol\;s^{-1}$, p<0.05). These results indicate that the measuring oxygen consumption by SECM can be used to evaluate bovine embryo quality.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.476-482
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• 1998

Growth sensitivity of bifidobacteria on oxygen hindered their industrial applications so that it was necessary to select oxygen-tolerant strains. Studies on their responses to oxygen might facilitate the effective utilization of bifidobacteria in industry. Oxygen-tolerant strain of Bifidobacterium longum JI-1 was able to remove 3% dissolved oxygen within 10 min whilst oxygen-sensitive strain of B. adolescentis, slime non-former, was not. The ability to remove environmental oxygen seemed to be related to the oxygen-tolerance of bifidobacteria. Mutant B. longum ADJ-1 was induced from the B. longum JI-1 under microaerobic atmosphere. There were no differences in sugar utilization pattern, NADH oxidative enzymes and cellular fatty acid compositions between them. The maximal cell density of the mutant was a little bit reduced to 81% of that of the mother strain. However, the mutant formed thick slime layer around its cell. The layer visualized with confocal scanning laser microscopy from the mutant was 6 ${\mu}{\textrm}{m}$ in diameter but that from the mother strain was only 3 ${\mu}{\textrm}{m}$. Therefore, the improved tolerances of the mutant might come from the slime layer, indicating the increase of the layer might be one of oxygen tolerance mechanisms for bifidobacteria.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.196-199
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• 2007

The chemical states of oxygen on the surfaces of $Pr_{1-x}Sr_{x}CoO_{3}$ (x=0.5 and 0.7) oxide systems were investigated by X-ray photoelectron spectroscopy. Merged oxygen peaks of $Pr_{1-x}Sr_{x}CoO_{3}$ (x=0.5 and 0.7) oxides could be divided as five sub-peaks. These five sub-peaks could be defined as lattice oxygen ($O_{L}$). chemisorbed oxygen peaks ($O_{C}$) and hydroxyl condition oxygen peak ($O_{H}$). In case of the $Pr_{0.5}Sr_{0.5}CoO_{3}$ and $Pr_{0.3}Sr_{0.7}CoO_{3}$, the binding energy (BE) of oxygen lattice were located at same BE. However, the BE of chemisorbed oxygen peaks including oxygen vacancy shows different BE. Especially, it was found that BE of chemisorbed oxygen peaks was increased when more Sr were substituted. Comparing atomic percentages of oxygens of $Pr_{0.5}Sr_{0.5}CoO_{3}$ and $Pr_{0.3}Sr_{0.7}CoO_{3}$, the ratio of $Pr_{0.3}Sr_{0.7}CoO_{3}$ was higher than that of $Pr_{0.5}Sr_{0.5}CoO_{3}$. It showed more chemically adsorbed site including oxygen vacancies were existed in $Pr_{0.3}Sr_{0.7}CoO_{3}$.