• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.5
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• pp.20-25
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• 2009

Residual extractives had a noticeable impact on the brightness of unbleached hardwood kraft pulps (trembling aspen). The brightness-impacting extractives were effectively removed by oxygen delignification. In addition, oxygen delignification was more effective in removing chromophores in hardwood unbleached kraft pulps than in those of softwood (loblolly pine). The residual extractives in unbleached hardwood kraft pulps also affected the pulp color, primarily redness and the L value. These redness-related extractives in unbleached hardwood kraft pulps were also effectively removed by oxygen delignification. There were no significant color differences between untreated and solvent-extracted oxygen-delignified aspen kraft pulps. The residual extractives in unbleached and oxygen-delignified softwood (loblolly pine) kraft pulps did not have a significant impact on either brightness or pulp color.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.4
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• pp.137-139
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• 2008

Floating zone, neutron transmutation-doped and magnetic Czochralski silicon crystals are being widely used for fabrication power devices. To improve the quality of these devices and to decrease their production cost, it is necessary to use large-diameter wafers with high and uniform resistivity. Recent developments in the crystal growth technology of Czochralski silicon have enable to produce Czochralski silicon wafers with sufficient resistivity and with well-controlled, suitable concentration of oxygen. In addition, using Czoehralski silicon for substrate materials may offer economical benefits, First, Czoehralski silicon wafers might be cheaper than standard floating zone silicon wafers, Second, Czoehralski wafers are available up to diameter of 300 mm. Thus, very large area devices could be manufactured, which would entail significant saving in the costs, In this work, the conventional Czochralski silicon crystals were grown with higher oxygen concentrations using high pure polysilicon crystals. The silicon wafers were annealed by several steps in order to obtain saturated oxygen precipitation. In those wafers high resistivity over $5,000{\Omega}$ cm is kept even after thermal donor formation annealing.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.1
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• pp.56-66
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• 2017

In this experimental study, it is designed and used the test engine bed which is installed with the exhaust gas recirculation, and in addition to equipped using by oxygen adder. It has been tested and analyzed the combustion and emission characteristics, cycle variability and engine performance by controlling the oxygen volume fraction, EGR rate, engine speed and equivalence ratio.

• 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.

• Archives of Pharmacal Research
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• v.19 no.2
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• pp.132-136
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• 1996

Exogenously applied oxygen free radical generating agent, pyrogallol, highly elevated extracellular glutamate accumulation and augmented N-methyl-D-aspartate (NMDA)-induced glutamate accumulation in cerebellar granule neuronal cells, but did not in astrocytes. Superoxide dismutase remarkably decreased the pyrogallol-induced glutamate accumulation, but either NMDA or kainate antagonists did not. In addition, pyrogallol did not affect the NMDAinduced intracellular calcium elevation. Pyrogallol partially blocked glutamate uptake into astrocytes. These results suggest that oxygen free radicals elevate extracellular glutamate accumulation by stimulating the release of glutamate as well as blocking the glutamate uptake.

• 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.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.126-126
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• 1998

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1224-1229
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• 2004

The blend films of poly(3-hydroxybutyric acid) (PHB) with chitosan were prepared and water vapor transmission rate, oxygen permeability and lipid permeability of the PHB/chitosan films were measured. Additionally, the biodegradability of the PHB/chitosan films was also evaluated. Water vapor transmission rate and oxygen permeability of the films decreased by the addition of chitosan. The addition of polyethylene glycol (PEG, plasticizer), however, increased the water vapor transmission rate and oxygen permeability of the films. In the evaluation of lipid permeability, all the films except PHB (the film made of only PHB) and PHB-P (the film made of PHB and PEG) did not permeate beef tallow for 24 hours. The consumed oxygen for PHB/chitosan films during incubation was greater than that for the control on the biodegradability determination of the films, which implies that PHB/chitosan films were degraded by the microorganisms. The higher PHB ratio of the films was, the faster biodegradation of the films occurred.