• Rapid Communication in Photoscience
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• v.5 no.2
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• pp.18-20
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• 2016

Through quantum chemical means, we inspect the energetics of the singlet oxygen formation with fluorescent proteins in their triplet excited states. By placing an oxygen molecule at varying distances, we discover that the energetic driving force for the singlet oxygen formation does not depend strongly on the chromophore $-O_2$ distance. We also observe that the chromophore vibrations contribute much to the energy gap modulation toward the surface crossing. Based on our computational results, we try to draw a series of rationalizations of different photostabilities of different fluorescent proteins. Most prominently, we argue that the chance of encountering a surface crossing point is higher with a protein with a lower photostability.

• Bulletin of the Korean Chemical Society
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• v.18 no.3
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• pp.287-291
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• 1997

The photochemical reaction of aqueous dichloromethane in the absence (saturated with argon) and the presence of O2 (saturated with air or oxygen) has been investigated using 184.9 nm UV light. The irradiation of the solution causes the formation of 1,2-dichloroethane, 1,1,2-trichloroethane, 1,1,2,2-tetrachloroethane and chloride ion. The initial quantum yield of the products in the absence of oxygen was determined to be 8.6 × 10-3, 7.3 × 10-3, 4.4 × 10-3 and 2.3 × 10-2, respectively. In addition to these main products, small amounts of 1,2,3-trichloropropane, 1,1,2,2,3-pentachloropropane, 1,1,2,3,3-pentachloropropane, 1,3-dichloropropane and 1,1,2,2,3,3-hexachloropropane were detected. In the presence of oxygen, hydrogen peroxide was also detected along with the products listed above. With increasing the concentration of oxygen, while formation of the chlorinated organic products diminished, formation of chloride ion increased. Probable reaction mechanisms for the photochemical reaction were presented on the basis of products analysis.

• Journal of Ceramic Processing Research
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• v.20 no.1
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• pp.18-23
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• 2019

Chemical looping combustion (CLC) is a promising carbon capture and storage (CCS) technology whose efficiency and cost primarily relies on the oxygen carrier materials used. In this paper, gadolinium-doped ceria (GDC, Ce0.9Gd0.1O1.95) was added as a promoter to improve the oxygen transfer rate of MgMnO3-δ oxygen carrier materials. Increasing GDC content significantly increased the oxygen transfer rate of MgMnO3-δ-GDC composites for the reduction reaction due to an increase in the surface adsorption of CH4 via oxygen vacancies formed on the surface of the GDC. On the other hand, the oxygen transfer rate for the oxidation reaction decreased linearly with increasing GDC content due to the oxygen storage ability of GDC. Adsorbed oxygen molecules preferentially insert themselves into oxygen vacancies of the GDC lattice rather than reacting with (Mg,Mn)O to form MgMnO3-δ during the oxidation reaction.

• Journal of the korean society of oceanography
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• v.31 no.1
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• pp.18-22
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• 1996

The effect of exogenous oxygen on hydrogen photoproduction was examined in the synchronously grown cells of marine Synechococcus sp. Miami BG 043511 under conditions of high cell density (0.6-0.8 mg chl-${\alpha}$ $ml^{-1}$) and high light intensity (1000 ${\mu}$E $m^{-2}$ $s^{-1}$). Hydrogen evolution after 20-h incubation did not decline under the initial oxygen concentrations up to 20%, but declined by half under 34% oxygen. 50% and 100% oxygen gas phase did not completely inhibit the hydrogen photoproduction during 40-h incubations. After 2-day pretreatment under 100% exogenous oxygen the hydrogen photoproduction capabilities were not irreversibly inhibited, which was demonstrated in the subsequent 9-day incubation under initial 0, 50 and even under 100% oxygen gas phase. This strain could be useful for developing a hydrogen photoproduction system under atmospheric oxygen concentration.

• 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.

• IE interfaces
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• v.18 no.2
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• pp.178-183
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• 2005

In this study, changes in memory performance, blood oxygen saturation and heart rate according to 30% concentration oxygen supply were observed. Ten healthy male and female college students (male:$25.8{\pm}0.8$ years, female: $24.2{\pm}1.9$ years) participated in the study. The experiment was performed as Rest (1min.), Control task (1min.), Word presentation (1min.), Reaction time task (1min.), Distractor (2min.), and Word recall (1min.) and the physiological signals such as blood oxygen saturation and heart rate were measured throughout the stages. Subjects who received 30% oxygen recalled more words than those who received 21% oxygen, which shows 30% oxygen supply has influenced positively on memory cognitive performance. When 30% concentration oxygen is supplied, the blood oxygen saturation in the task phases was increased and the heart rate decreased when comparing to 21%. It means that 30% oxygen can stimulate brain activation by increasing actual blood oxygen concentration in the process of cognitive performance, and the heart rate decreases because enough oxygen is supplied to process the cognitive performance.

• Journal of the Korean Ceramic Society
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• v.34 no.2
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• pp.171-174
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• 1997

It was experimentally identified, for the first time, that oxygen phonons play an important role in the low temperature degradation(tetragonallongrightarrowmonoclinic phase transformation) of yttria stabilized tetragonal zir-conia polycrystals (Y-TZP). The degradation accompanied by immersing the samples in the boiling water were markedly reduced by substituting of 18O for 16O in Y-TZP. This was attributed to the heavier mass of 18O which leads to the smaller probability to find oxygen atoms beyond certain critical displacements.

• Proceedings of the ESK Conference
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• 2004.10a
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• pp.18-18
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• 2004

• Journal of Environmental Science International
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• v.4 no.3
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• pp.259-267
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• 1995

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated slut비e and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floe. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floe. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0mg/$\ell$ to 258 mg/$\ell$. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about loom in this study.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.73-78
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• 2009

Processed meatball products were packaged in a passive package without oxygen scavenger as 1 control and 3 active packages of which have PP-based oxygen scavenger master batch materials (OSMB) of 40, 80, and 100%(w/w) in the middle layer and stored at 23 and $30^{\circ}C$ up to 9 months. Quality changes of packaged products were evaluated by measuring the oxygen concentration of the headspace in containers, thiobarbituric acid (TBA), color, and flavor. The oxygen concentration of the package having 100% OSMB was lower than those of 40 and 80%. The color changes and TBA values of the meat ball in the package containing 100% OSMB were the least among the treatments. Using principal component analysis (PCA), the control showed more flavor change than the packages containing oxygen scavenger. As a result, all active packages could extend the shelf life of the meatball products compared with that of the passive package.