• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.57-64
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• 2002

This paper describes the results of a series of experiments executed by using two pilot-scale oxv-fuel burners are designed for maximum capacity of 50,000 kacl/hr, 300,000 kcal/hr and installed in the test furnace. The effects of turn-down ratio, excess oxygen ratio, nozzle exit velocity, injection angle, swirl vane angle and inlet oxygen temperature on the combustion characteristic are investigated. Temperature distributions are measured using R-type and Molybdenum sheathed C-type thermocouple. The results showed that maximum temperature and mean temperature increase with the increase of turn-down ratio and inlet oxygen temperature. The maximum flame temperature was increased about 35% compared to the case of equivalent air operated condition. In addition, Optimum excess oxygen ratio and nozzle characteristics are obtained for this oxy-fuel glass melting furnace.

• Korean Journal of Materials Research
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• v.21 no.11
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• pp.617-622
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• 2011

The effect of oxygen on the shape memory characteristics in Ti-18Nb-6Zr-XO (X = 0-1.5 at%) biomedical alloys was investigated by tensile tests. The alloys were fabricated by an arc melting method at Ar atmosphere. The ingots were cold-rolled to 0.45 mm with a reduction up to 95% in thickness. After severe cold-rolling, the plate was solution-treated at 1173 K for 1.8 ks. The fracture stress of the solution-treated specimens increased from 450 Mpa to 880 MPa with an increasing oxygen content up to 1.5%. The fracture stress increased by 287MPa with 1 at% increase of oxygen content. The critical stress for slip increased from 430 MPa to 695 MPa with an increasing oxygen content up to 1.5 at%. The maximum recovery strain of 4.1% was obtained in the Ti-18Nb-6Zr-0.5O (at%) alloy. The martensitic transformation temperature decreased by 140 K with a 1.0 at% increase in O content, which is lower than that of Ti-22Nb-(0-2.0)O (at%) by 20 K. This may have been caused by the effect of the addition of Zr. This study confirmed that addition of oxygen to the Ti-Nb-Zr alloy increases the critical stress for slip due to solid solution hardening without being detrimental to the maximum recovery strain.

• Macromolecular Research
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• v.12 no.6
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• pp.598-603
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• 2004

Cellulose nitrate (CN) composite membranes, containing cobalt porphyrin (CoP) complexes self-assembled within nanometer-sized rhenium clusters (ReCoP), have been prepared and their oxygen and nitrogen gas perme­abilities were analyzed. The solubility of ReCoP and the characteristics of the corresponding composite membranes were analyzed using a Cahn microbalance, FT-IR spectroscopy, wide-angle X-ray scattering, and differential scanning calorimetry. The nitrogen permeability through the CN composite membranes decreased upon addition of ReCoP and CoP, which implies that the presence of these oxygen carrier complexes affects the structure of the polymer matrix. The oxygen permeability through the composite membranes containing small quantities of ReCoP decreased, but it increased upon increasing the concentration. The oxygen gas transport was affected by the matrix at low ReCoP concentrations, but higher concentrations of ReCoP increased the oxygen permeability as a result of its reversible and specific interactions with oxygen, effectively realizing ReCoP carrier-mediated oxygen transport.

• Toxicological Research
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• v.13 no.3
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• pp.223-228
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• 1997

Quinones have been reported to undergo nonenzymatic reaction with thiols to generate reactive oxygens. It is therefore possible that the nonenzymatic reaction of quinones with thiols in plasma could lead to potentJared cellular toxicity or disease. When 1 mM menadione was added in plasma under pH 11.2, 7.4 and 5.0, the increase in oxygen consumption rate was the order of pH 11.2 > pH 7.4 > pH 5.0. In addition, oxygen consumption rates under plasma anticoagulated with trisodium citrate solution (pH 7.85) was significantly higher than those with acid-citrate-dextrose solution (pH 6.87). SOD and catalase reduced the rate of oxygen consumption induced by menadione in plasma. Taken together, these results suggest that the menadione-induced increased oxygen consumption was due to nonenzymatic reaction of menadione with thiols in the plasma. The presence of plasma has an additive effect on the increased oxygen consumption rates induced by the menadione treatments on our model tissue, platelets, as compared between washed platelet (WP) and platelet rich plasma (PRP). Cytotoxicity, as determined by LDH release, are well correlated with the oxygen consumption rates observed in each system and strongly suggest that menadione-induced cytotoxicity can be increased with the presence of blood plasma.

• Journal of Embryo Transfer
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• v.29 no.3
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• pp.257-264
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• 2014

Recently, several approaches have been used to measure the oxygen consumption rates of individual embryos, but relationship between oxygen consumption and pregnancy rates of Hanwoo following embryo transfer has not yet been reported. In this study, we investigated the correlation between oxygen consumption rate and pregnancy rates of Hanwoo embryo using a SECM. In addition to, the expression of apoptosis-related genes was determined using real-time PCR by extracting RNA according to the oxygen consumption of in vivo embryo. First, we found that the oxygen consumption significantly increased in blastocyst-stage embryos (blastocyst) compared to early blastocyst stage embryos, indicating that oxygen consumption reflects the embryo quality (Grade I). The oxygen consumption or GI blastocysts were significantly higher than those of GII blastocysts ($10.2{\times}10^{14}/mol\;s^{-1}$ versus $6.4{\times}10^{14}/mol\;s^{-1}$, p<0.05). Pregnant rate in recipient cow was 0, 60 and 80% in the transplantation of embryo with the oxygen consumption of below 10.0, 10.0~12.0 and over $12.0{\times}10^{14}/mol\;s^{-1}$, respectively. Apoptosis regulatory genes, Hsp-70.1 were significantly increased in over-10.0 group than below 10.0 group but in Caspase-3, Bax and P53 gene, there was no significant difference. In conclusion, These results suggest that measurement of oxygen consumption maybe help increase the pregnant rate of Hanwoo embryos.

• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.127-134
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• 1998

Stainless steel is being used widely for various purposes due to its good corrosion resistance. There has been much research to produce a colored and corrosion-resistant stainless steel by several methods to use in decorating. In this experiment, we coated TiN(C,O,H)films on the SUS304 substrates with the DC magnetron sputtering system and then studied the texture and color of the films as a function of additional gases being inserted into the system. A (220) texture of TixN film changed to (200) by the addition of either hydrogen or the acetylene and changed further to (111) with an increase of the additional acetylene content. The addition of oxygen gas changed from the texture(220) to (111) to (200). The color of the TixN film changed from gold to gray to green with the increase of the content by the addition of oxygen gas, while it changed to pink and finally to gray with the increased of the content by the addition of acetylene gas. Reflectance increased in the region of short wavelength by the addition of hydrogen, but decreased with the increase of the oxygen and the acetylene content.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.93-100
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• 1992

Sinterability, mechanical and electrical properties of yttria-stabilized zirconia(92 mole% $ZrO_{2}$+8 mole% $Y_{2}O_{3}$) doped with 0.5 mole% $SiO_{2}$ and $0{\sim}2.0 mole%{\;}Al_{2}O_{3}$ were studied as a function of $Al_{2}O_{3}$ addition. Sintered density increased with increasing $Al_{2}O_{3}$ addition up to 0.5 mole % but leveled off with further addition. Victors hardness is proportional to sintered density. The specimen with 0.5 mole% $Al_{2}O_{3}$ and 0.5 mole% $SiO_{2}$ exhibited the maximum electrical conductivity and revealed a maximum electromotive force for a given oxygen partial pressure. Experimental voltage curve of this oxygen sensor take on a sharper, more steplike transition at the stoichiometric A/F ratio than those of other commercial oxygen sensors.

• KSBB Journal
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• v.13 no.6
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• pp.644-648
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• 1998

In the production of a low cost bacterial insecticide, it is important to produce a high spore concentration using low price substrates. Experiments were carried out to investigate the effects of the addition of mineral salts and glucose, and of dissolved oxygen concentration on the cell growth and spore formation of Bacillus thuringiensis var aizawai using a cheap wheat and soybean meal in the batch culture. The maximum viable cell number was 1.2${\times}$109 CFU/mL at 12 hr culture and spore yield was 54.2% at 74 hr culture using an industrial medium containing 20 g/L wheat meal and 30 g/L soybean meal under 1.0 vvm aeration and 200 rpm agitation. The cell growth and the spore formation were not enhanced by the addition of mineral salts in industrial medium, whereas th addition of 10g/L glucose decreased the cell growth and spore formation. We could obtain a maximum viable cell number of 2.2${\times}$109 CFU/mL and spore number of 1.9${\times}$109 CFU/mL at the dissolved oxygen concentration of 60% of saturation. The spore concentration was enhanced approximately by 2 times as compared to the dissolved oxygen concentration of 50%. In the bench-scale culture, the maximum viable cell and spore number were 2.5${\times}$109 CFU/mL, and 2.2${\times}$109 CFU/mL, respectively under 1.0 vvm aeration and 400 rpm agitation. The spore yield was 88% based on the maximum viable cell number. As a result, it was confirmed that the production of high spore concentration could be obtained by a bench-scale culture using an industrial medium.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.1
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• pp.51-56
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• 2015

The object of this study is to obtain the optimum mix proportion of halogen free compound with flame resistance and, for the purpose, thermal/electrical characteristics test are conducted using compatibilizing agents, flame resistance agents, hydroxide aluminum, sunscreen, antioxidant and silicon oil on the base resin of linear low density polyethylene (LLDPE), Ethylene vinyl acetate copolymer (EVA). Existing compound method accompanies many requirements to be satisfied including a lot of addition of flame resistance agents, prohibition of impact on mixing capability with base and property and etc. In this study, different from the existing method, the optimum mix proportion is determined and experimented by adding nano clay. Oxygen index test shows no difference between specimens while T-6, T-9 shows oxygen index of 29[%] and 26[%], respectively. This is concluded that hydroxide aluminum, which is a flame resistance agent, leads low oxygen index. From UL94-V vertical flame resistance test, the combustion behavior is determined as V-0, Fail based on UL94-V decision criteria. Viscometry shows low measurements in specimens with separate addition of compatibilizing agents or nano clay. Volume resistivity test shows low measurement mainly in specimens without compatibilizing agents. Therefore, with the flame resistance compound shows better performance for thermal/electrical property and the optimum mix proportion are achieved among many existing materials.

• Journal of Industrial Technology
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• v.39 no.1
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• pp.1-5
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• 2019

In this study, we examined the effect of NO addition on the ozone-induced soot oxidation activity of $LaMnO_3$ perovskite catalysts. The addition of 10~20% NO ($NO_2$) with respect to the concentration of ozone effectively enhanced the rate of ozone-induced soot oxidation rate over $LaMnO_3$. However, the excessive addition of NO ($NO_2$) was detrimental to ozone-induced soot oxidation activity. It is supposed nitrogen oxides would adsorb on the catalyst and then react with carbon-oxygen species developed on soot surface, but an excessive addition of nitrogen oxide would inhibit the formation of carbon-oxygen species, which is a key intermediate in the reaction, and consequently suppress the oxidation rate of soot.