• Fire Science and Engineering
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• v.22 no.3
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• pp.300-304
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• 2008

The flame retardancy was evaluated to present as the fundamental data to decrease the fire hazard of polymers and life losses according to the addition of clay. The combustion characteristics were examined to increase flame retardancy and to decrease smoke yield of epoxy by the addition of clay such as montmorillonite in this study. For this study, the experiments of flame retardancy were conducted the measurement of the limiting oxygen index (LOI), char yield, and smoke density. As MMT concentration increased, LOI and char yield increased. This result showed that the flame retardancy of epoxy/MMT composite was improved. On the contrary, smoke density increased.

• Journal of Photoscience
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• v.1 no.1
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• pp.47-52
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• 1994

Effects of HgCl$_2$-treatment on electron transport, chlorophyll a fluorescence and its quenching were studied using isolated barley (Hordeum vulgare L. cv. Albori) chloroplasts. Depending on the concentration of HgCI$_2$, photosynthetic oxygen-evolving activities of photosystem II (PS II) were greatly inhibited, whereas those of photosystem I (PS I) were slightly decreased. The inhibitory effects of HgCl$_2$ on the oxygen-evolving activity was partially restored by the addition of hydroxyamine, suggesting the primary inhibition site by HgCl$_2$2-treatment is close to the oxidizing site of PS tl associated with water-splitting complex. Addition of 50 $\mu$M HgCI$_2$ decreased both photochemical and nonphotochemical quenching of chlorophyll fluorescence. Especially, energy dependent quenching (qE) was completely disappeared by HgCl$_2$-treatment as observed by NH$_4$CI treatment. In the presence of HgCI$_2$, F'o level during illumination was also increased. These results suggest that pH gradient across thylakoid membrane can not be formed in the presence of 0 $\mu$M HgCl$_2$. In addition, antenna pigment composition might be altered by HgCl$_2$-treatment.

• Korean Journal of Food Science and Technology
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• v.47 no.5
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• pp.561-566
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• 2015

Effect of the addition of egg yolk lecithin at a concentration of 350 mg/kg on iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation of a water/canola oil emulsion (W/O) during storage at $25^{\circ}C$ was studied based on headspace oxygen consumption and hydroperoxide production. Changes in the phospholipid (PL) composition of the emulsion were determined by high performance liquid chromatography. Headspace oxygen consumption and hydroperoxide content of the emulsion increased with storage time, and addition of egg yolk lecithin did not have any significant effect on these parameters during iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation of the emulsion. PL content of the emulsion decreased during both oxidations, and the degradation rate was higher during autoxidation than during photosensitized oxidation. Phosphatidylcholine content ratio tended to increase during autoxidation. The results suggest that egg yolk lecithin in canola oil emulsion behaves differently during iron-catalyzed autoxidation and chlorophyll-photosensitized oxidation.

• Journal of the Korean Ceramic Society
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• v.23 no.3
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• pp.87-93
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• 1986

Yttria-bismuth-stabilized zirconia was investigated with respect to the amount of $Bi_2O_3$ addition in the ran-ge of 0.5~5mol% to the base composition of $(ZrO_2)_{0.92}(Y_2O_3)_{0.08}.Bismuth was introduced into the ma-terial with $Bi_2O_3-SiO_2$ glasses in order to reduce the evaporation of components. The sinterbility evaporation of components phase formation and microstructure were evaluated depending on the amount of $Bi_2O_3-SiO_2$ glass addition. Two probe A. C conductivity measurement was subjected to all the specimens and the result was discussed on the possible substitution of $Bi^{3+}$ for $Zr^{4+}$ and interistial $Si^{4+}$ in the fluorite structure of zirconia crystal there-upon the possible change in the capability of oxygen transference within the material. It was found that the addition of $Bi_2O_3$ could improve the sinterbility of material very much while not so much.oxygen sensing material suitable for relative low temperature firing.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.5
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• pp.343-348
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• 2009

The present study has experimentally investigated the effects of $CO_2$ diluted oxygen on the structure of swirl-stabilized flame in a lab-scale combustor. The methane fuel and oxidant mixture gas ($CO_2$ and $O_2$) were mixed in a pre-mixer and introduced to the combustor through different degrees of swirl vanes. The flame characteristics were examined for various amount of carbon dioxide addition to the methane fuel and various swirl strengths. The effects of carbon dioxide addition and swirl intensity on the combustion characteristics of pre-mixed methane flames were examined using chemiluminescence techniques to provide information about flow field. The results show that the hot combustion zone increases at the upstream reaction zone because of an increase in the recirculation flow for an increase in swirl intensity. The hot combustion zone is also increased at the downstream zone by recirculation flow because of an increase in swirl intensity which results in higher centrifugal force. The OH and CH radical intensities of reaction zone decrease with carbon dioxide addition because the carbon dioxide plays a role of diluted gas in the reaction zone.

• Korean journal of food and cookery science
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• v.33 no.3
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• pp.275-284
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• 2017

Purpose: This study was performed to evaluate the effects of sannamul or herb extract addition to a soybean oil-in-water emulsion during photooxidation in the presence of chlorophyll. Methods: The emulsion mainly consisted of purified soybean oil and citric acid buffer (pH 4.0) at a weight ratio of 4 to 6, with chlorophyll a addition at 6 mg/kg. Ethanol extract of daraesoon, samnamul, basil, or peppermint was selectively added to the emulsion at 400 mg/kg, and emulsions in glass serum bottles were oxidized at $5^{\circ}C$ under 2,600 lux light for 48 hours. Lipid oxidation of the emulsions was evaluated based on determination of headspace oxygen content, peroxide value, and p-anisidine value. Pigments and antioxidants were also monitored. Results: The emulsion with added samnamul extract with high contents of polyphenols and low chlorophyll content showed lower oxygen consumption, peroxide values, and p-anisidine values, whereas basil and peppermint extracts with high chlorophyll contents increased photooxidation. Chlorophylls were degraded during photooxidation of the emulsions, and the degradation rate was highest in the emulsion with added samnamul extract. Conclusion: The high antioxidant activity of samnamul extract in the photooxidation of soybean oil-in-water emulsion could be due to low chlorophyll content, high concentrations of polyphenol compounds in the extract, as well as rapid degradation of chlorophylls during oxidation.

• Journal of Korea Foundry Society
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• v.15 no.2
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• pp.175-183
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• 1995

It is difficult to remove such interstitial impurities as sulfur, oxygen, hydrogen and carbon in Fe-Ni alloys. Thermodynamic and kinetic studies were carried out on the behavior of hydrogen gas, oxygen gas, Si, Al and slag, and the reaction time by the $Ar/Ar-H_2$ plasma and electron beam melting. After the addition of Al, Si, they were melted by Ar plasma with reaction time changed. 80%Ni-Fe alloys showed a better deoxidation than 36%Ni-Fe alloys. At $Ar-H_2$ plasma melting, the deoxidation was significant. In the case of the electron beam melting, the residual oxygen was higher than in Ar plasma melting because electron beam melting temperature was lower than that of Ar plasma. For the decaburization, it was melted by $Ar-O_2$ plasma melting, which could remove effectively carbon by activated oxygen in plasma. We added slag to Fe-Ni alloys for the desulfurization. As the result of this experiments, the amount of residual sulfur was not changed according to the slag ratio and reaction time.

• Korean Journal of Materials Research
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• v.12 no.11
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• pp.889-893
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• 2002

The reactions of $Cu/Ti/SiO_2$ structures at temperatures ranging from 200 to $700^{\circ}C$ have been studied for various Ti thicknesses. The reaction products initially formed, at around $300^{\circ}C$, were a series of Cu-Ti intermetallics ($Cu_3$Ti/CuTi) with the oxygen dissolved in the Ti moving from the compounds into the remaining unreacted Ti. At $500^{\circ}C$, the $Cu_3$Ti was converted into Cu-rich intermetallics, $Cu_4$Ti, which grew at the expense of the CuTi due to the increased oxygen content in the Ti. In addition, the outdiffusion of Ti, to the Cu surface, and the $Ti-SiO_2$ reactions, caused an abrupt increase in the oxygen content in the Ti layer, which placed thermodynamic restraints on further Ti reactions. Furthermore, thinner Ti layers showed a higher increasing rate of oxygen accumulation for the same consumption of Ti, which led to significantly reduced Ti consumption. The $SiO_2$ film under the Ti diffusion barrier was more easily destroyed with increasing Ti thickness.

• Journal of Pharmacopuncture
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• v.2 no.1 s.2
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• pp.13-25
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• 1999

This study was undertaken to determine whether Juglandis Semen (JAS) extraction exerts protective effect against oxidant-induced inhibition of $Na^+$-pump activity in cerebral cortex. $Na^+$-pump activity was estimated by measuring ouabain-sensitive oxygen consumption. The oxygen consumption significantly inhibited by 1 mM t-butylhydroperoxide (tBHP), which was prevented by addition of 2% JAS extraction. The oxygen consumption was increased by an increase in $Na^+$ concentration from 5 to 100mM, $K^+$ concentration from 0.5 to 10 mM, and $Mg^{++}$ concentration from 0.2 to 5 mM. These changes in ion concentrations did not affect the inhibitory effct of tBHP and protective action of JAS on oxygen consumption. tBHP(1mM) produced a significant increase in lipid peroxidation in cerebral cortex, which was prevented by 2% JAS extraction. These result suggest that JAS exerts protective effect against tBHP-induced inhibition of $Na^+$-pump activity in the cerebral cortex, this effect may be due to by an antioxidant action.

• Journal of the Korean Society of Industry Convergence
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• v.18 no.2
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• pp.110-118
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• 2015

In this study, it is designed and used the test engine bed which is installed with turbocharger, and in addition to equipped using by oxygen adder. It has been controlled the oxygen volumetric fraction of intake air chrge, and supercharged flow rate into the cylinder of SI 4-stroke engine, and then, has been analyzed engine performance, combustion characteristics, and exhaust emission as analysis parameters. The tested parameters were the oxygen fraction and the variation of engine speed and air-fuel ratio.