• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.171-174
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• 2000

The effect of the dissolved oxygen (DO) concentration on the production of manganese peroxidase by Phaenerochaete chrysosporium was studied in the immobilized reactor system. The oxygen levels significantly affected the production of manganese peroxidase (MnP) as well as that of $H_2O_2$. It is known that a high oxygen level is required to produce this enzyme. In this study, however, higher DO concentrations above a critical DO concentration inhibited MnP production. It is thought that a greater $H_2O_2$ production seen with higher DO concentrations caused adverse effects on the MnP production. On the other hand, with lower DO concentrations, $H_2O_2$ did not accumulate enough to stimulate MnP production.

• Journal of Environmental Health Sciences
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• v.12 no.2
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• pp.11-15
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• 1986

Hydroxlamine effect on the determination of dissolved oxygen by the azide-modified Winkder method and polarography has been studied. It was found that hydroxylamine interference on the dissolved oxygen by the azide-modified Winklet method can be eliminated completely by using permanganate. An inexpensive and convenient polarograph device was constructed. Dissolved oxygen in an air-saturated 0.1 F KCl solution undergoes, independent of hydroxylamine concentrations a two-step irreversible reduction at the dropping electrode the $H_2O_2$ produced in the first step is reduced to $H_2$O in the second. Two waves of equal size result, the first with a half-wave potential (E1/2) at about -0.13 V and the second at about -0.91 V (vs. SCE).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.2
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• pp.109-115
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• 2005

The study of Oxygen Vacancy on SnO$_2$ thin films grown by thermal chemical vapor deposition were investigated with different substrate temperature. X-ray diffraction showed that the crystallinity of the grown thin films increased with increasing substrate temperature. Two narrow peaks and two broad peaks were observed from the photoluminescence measurements at 6 K. The intensity and shape of the broad peaks were changed with increasing substrate temperature. It was concluded that the origin of the broad peak at 2.4 eV was due to oxygen vacancies and that of peak at 3.1 eV was related to structural defects. Hall effect measurements showed that the carrier density was decreased as increasing deposition time from 10 to 30 min., but increased for the deposition of 60 min.

• 한국해양학회지
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• v.3 no.1
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• pp.1-7
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• 1968

Two major processes that affect the vertical distribution of apparent pH in the Subarctic region of the Northeastern Pacific Ocean are (1) apparent oxygen utilization by marine organisms and (2) carbonate dissolution. Simplified mathematical approximations show that, in the pH ravge of 7.2 to 8.3, the utilization of 0.1 mM of oxygen (2.24 ml/liter) lowers the pH by 0.20 units and 0.1 mM of carbonate dissolution increases the pH by 0.25 units. Since Oxygen utilization exceeds 0.3 mM while the carbonate dissolution, with respect to the surface, is about 0.05mM, the effect of oxygen utilization is much greater than the dissolution effect of carbonate on the pH of seawater.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.632-635
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• 2007

This study examined the neuroprotective effect of scopoletin from Angelica dahurica against oxygen and glucose deprivation-induced neurotoxicity in a rat organotypic hippocampal slice culture. Scopoletin reduced the propidium iodide (PI) uptake, which is an indication of impaired cell membrane integrity. In addition, it inhibited the loss of NeuN, which represents the viability of neuronal cells. The results suggests that scopoletin from A. dahurica protects neuronal cells from the damage caused by oxygen and glucose deprivation.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.29-39
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• 2000

In order to elucidate the toxic mechanism of oxygen radicals in cultured mouse spinal sensory neurons, cytotoxic effect of oxygen radicals was evaluated by M1T assay and NR assay. In addition, protective effect of Sopunghwalhyultang(SPHHT) water extract on oxidant-induced neurotoxicity was investigated on these cultures. Spinal sensory neurons derived from mice were cultured in mediums containing various concentrations of Xanthine Oxidase / Hypoxanthine(XO/HX). Cell viability was measured by MTT assay and NR assay. XO/HX-mediated oxygen radicals remarkably decreased cell viability of cultured spinal sensory neurons in a dose-and time-dependent manner. And also, SPHHT blocked XO/HX-induced neurotoxicity in these cultures. These results suggest that oxygen radicals are toxic and SPHHT are effective in blocking against the oxidant-induced neurotoxicity in cultures of spinal sensory neurons of mice.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.857-858
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• 2006

In order to clarify the wear resistance as cutting tools, the effect of oxygen addition on oxidation behavior of the ${\beta}-Si_3N_4$ ceramics with 5 mass% $Y_2O_3$ and 2 or 4 mass% $Al_2O_3$ was investigated by performing oxidation tests in air at $1300^{\circ}$ to $1400^{\circ}C$ and cutting performance tests. From test results, we could conclude that the mechanical properties of ${\beta}-Si_3N_4$ ceramics depending on oxygen introduction are much effective on cutting performance improvements of ${\beta}-Si_3N_4$ ceramics.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.309-311
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• 2015

The MILD(Moderate or Intense Low-oxygen Dilution) combustion has been considered as one of the promising combustion technology for high thermal efficiency and low emissions. In this paper, the effect of fuel oxygen impingement on formation of MILD combustion was analyzed using numerical simulation. This investigation was simulated under the thermal intensity $0.04MW/m^3$ and equivalence ratio 0.91. The results show that the temperature distribution was become relatively uniform and the amount of CO emission was decreased as the increase of oxygen jet velocity and impinging angle.

• Journal of Advanced Marine Engineering and Technology
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• v.26 no.6
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• pp.679-687
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• 2002

In this study, a cycle simulation using a two-zone model is carried out to investigate the effect of intake charging conditions such as oxygen concentration, temperature and pressure on NO emissions in a DI diesel engine. The model is validated against measurements in terms of cylinder pressure, torque, BSFC and NOx emissions with 2902 cc DI diesel engine. Calculated results can be summarized as follows. The oxygen concentration in the intake charge is decreased with increasing of EGR rate and equivalence ratio. As the intake oxygen concentration is reduced, the combustion pressure and the burned gas temperature decrease and, as a result, NO formation decreases. Also, the results show that as the intake pressure increases and the intake temperature decreases, NO emissions are effectively reduced.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.951-956
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• 2005

Selection of oxygen-tolerant strains and elucidation of their oxygen tolerance mechanism were crucial for effective use of bifidobacteria. Oxygen-tolerant bifidobacteria were able to significantly remove environmental oxygen (oxygen removal activity) as compared to oxygen-sensitive strains. Most oxygen removal activity was inhibited by heat treatment and exposure to extreme pH (2.0) of bifidobacterial cell. NADH oxidase was major enzyme related to oxygen removal activity. Oxygen-tolerant bifidobacteria possessed high NADH peroxidase activity level to detoxify $H_2O_2$ formed from reaction of NADH oxidase. Addition of oxygen to anaerobic culture broth significantly increased activities of HADH oxidase and NADH peroxidase within 1hr and rapid increment of oxygen concentration was prevented. Results showed NADH oxidase and NADH peroxidase of oxygen-tolerant bifidobacteria played important roles in elimination of oxygen and oxygen metabolite $(H_2O_2)$.