• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.759-760
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• 2006

Ti-6Al-4V has low specific gravity, high corrosion resistance and superior mechanical properties but it is very difficult to control oxygen content in MIM process. It is necessary to use powders with coarse particle size to decrease oxygen content of powders, so feedstocks with poor fluidity and sintered bodies with lower density are obtained in such cases. Fine titanium hydride-dehydride powders were blended with atomized powders to accomplish higher fluidity and sintered density. Sintered bodies had higher sintered density and mechanical properties equivalent to those of wrought materials by controlling oxygen content less than 0.35mass%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.185-187
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• 2004

The electron concentration of ZnO thin film fabricated by pulsed laser deposition was controlled by varying oxygen gas pressure. The electron concentration of ZnO was increased from $10^{17}\;to\;10^{19}/cm^3$ as oxygen gas pressure increased from 20 mTorr to 350 mTorr. Ultraviolet(UV) intensity of photoluminescence of ZnO was controlled, too. UV intensity of ZnO was increased as oxygen gas pressure increased from 20 mTorr to 350 mTorr. The relation between electron concentration and UV intensity was investigated.

• Biomolecules & Therapeutics
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• v.3 no.4
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• pp.260-265
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• 1995

In an attempt to define the early biochemical determinants that participate in the pathogenesis of glycerol-induced nephrotoxicity, especially focusing on oxygen free radicals, we studied malondialdehyde (MDA) level and the activities of catalase and superoxide dismutase in the renal cortex of rats, and the concentrations of blood urea nitrogen(BUH) and serum creatinine of rats at 24hr after the injection of a 50% solution of glycerol. Sprague-Dawley albino rats weighing 240 to 260 mg were injected intramuscularly with a 50% solution of glycerol(2 mι/kg, 4 mι/kg and 8 mι/kg). The group treated with glycerol showed significantlv higher MDA level and catalase activity, lower SOD activity and higher BUN and serum creatinine concentrations at 24 hr after the injection as compared to those of control group. These results suggest that the excessive oxygen free radicals resulting from the depression of SOD activity is an important determinant in the pathogenesis of glycerol-induced nephrotoxicity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.1
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• pp.61-69
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• 2015

The objective of this study is to experimentally investigate the mixed flow behaviors and oxygen transfer characteristics of a vertical orifice ejector. The experimental apparatus consisted of an electric motor-pump, an orifice ejector, a circulation water tank, an air compressor, a high speed camera unit and control or measurement accessories. The mass ratio was calculated using the measured primary flow rate and suction air flow rate with experimental parameters. The visualization images of vertically injected mixed jet issuing from the orifice ejector were qualitatively analyzed. The volumetric oxygen transfer coefficient was calculated using the measured dissolved oxygen concentration. At a constant primary flow rate, the mass ratio and oxygen transfer coefficient increase with the air pressure of compressor. At a constant air pressure of the compressor, the mass ratio decreases and the oxygen transfer coefficient increases as the primary flow rate increases. The residence time and dispersion of fine air bubbles and the penetration of mixed flow were found to be important parameters for the oxygen transfer rate owing to the contact area and time of two phases.

• Korean Journal of Veterinary Research
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• v.9 no.1
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• pp.11-22
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• 1969

Experimental studies were performed to observe the difference in tolerance of small animals to oxygen poisoning, and also to examine the effects of certain drug for it. The three experimental groups consisted of mature rat group, immature rat group and mouse group. The animals were exposed to 5 atm. of 100% oxygen using hyperbaric chamber, and they were observed for oxygen poisoning by pulmonary and central nervous system manifestation. The tolerance to oxygen poisoning was represented by half fatality time in each experimental group. The drug applied was ammonium chloride $NH_4Cl$ and it was administered intraperitoneally in various dosages for particular attribution of its prophylactic effect. The following conclusions were made; 1. The immature rat group showed the higher degree of tolerance to oxygen poisoning, as evidenced by a more prolonged half fatality time in the group. No significant difference in the half fatality time between the mature rat and the mouse group was observed. 2. The fact that the immature group showed the higher degree of tolerance as compared with the mature rat group represented by delayed onset of convulsion. 3. There was a remarkable difference in the Lung Weight/Body Weight ratio between the experimental and control group. 4. The animals with a shorter half fatality time uniformally displayed an earlier onset of convulsive seizure as the sign of oxygen poisoning and a significant elevated Lung Weight/Body Weight ratio. 5. Ammonium chloride at the dosage of 450mg per kg body weight had the most pronounced prophylactic effect on oxygen poisoning.

• Analytical Science and Technology
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• v.37 no.5
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• pp.261-270
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• 2024

This study examines portable Gas Chromatography (GC) for the quantitative analysis of oxygen and impurities, focusing on the development and validation of a method to determine oxygen, carbon monoxide, carbon dioxide, methane, and nitrogen in medical compressed oxygen gas. The goal is to ensure the quality of medicalgrade oxygen. The method's validation assessed its metrological characteristics, demonstrating specificity through clear chromatographic separation of the target gases and the absence of these peaks in the carrier gas chromatogram. It exhibited linearity within the designated concentration ranges, while precision met permissible standards, with the relative standard deviation for intermediate precision being less than 4% for carbon monoxide (0.00025 - 0.00099 %), less than 3 % for methane (0.0005 - 0.00246%) and carbon dioxide (0.0050 - 0.0150 %), less than 2% for nitrogen (0.1 - 0.7 %), and less than 0.01% for oxygen (99.27 - 99.98%). Overall, the validation results confirm the suitability of this analytical method for the quantitative determination of the aforementioned gases in medical compressed oxygen using portable GC with microchromatographic columns and detectors.

• The Korean Journal of Physiology
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• v.4 no.2
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• pp.45-51
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• 1970

In an attempt to better understand the effect of whole body irradiation on the spontaneous motility and oxygen consumption rate of the isolated mouse duodenum, a whole body X-irradiation of 1,000r. was given to albino mouse, and 1) the total length of contraction of isolated duodenum was recorded on kymograph every five minutes for 60 minutes, 2) glucose and 5-hydroxytryptamine(5-HT) were added to the reaction medium of Kreb's-Ringer-bicarbonate buffer(KRB) and response of the isolated duodenum to the drugs was observed, and 3) the oxygen consumption rate $(QO_2)$ of the isolated duodenum as well as the effect of glucose and 5-HT on $QO_2$ were measured by Warburg's standard manometric method and the comparison was made with the control(i.e. normal) group. The results thus obtained are summarized as follows. 1. The spontaneous motility of the isolated duodenum in the irradiated groups showed a significantly elevated pattern for the first 15 minutes comparing with the control. The motility, however, decreased after 15 minutes and remained so in the irradiated groups to the level of the nonirradiated control, but 24 hours post-irradiation group showed a tendency of an increased motility while one hour post-irradiation group showed no difference comparing with the control. 2. Addition of glucose produced generally elevated motility of the isolated duodenum in both irradiated and non-irradiated groups comparing with the control throughout the experiment, but no difference was observed in contractile amplitude between the irradiated and non·irradiated groups. 3. When 5-HT was added to the irradiated group, the contractile amplitude of isolated duodenum was similar to that of the control, and 5-HT alone caused a slight increase of the motility comparing with the control. 4. The oxygen consumption rate $(QO_2)$ of the isolated duodenum was found to be ,slightly increased in one hour post·irradiated group, but similar in 24 hour post·irradiated group comparing with the control. Glucose produced a significant increase of $QO_2$ in all the groups, but 5-HT produced a tendency of decrease of $QO_2$ in all the groups.

• Korean Journal of Food Science and Technology
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• v.12 no.4
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• pp.229-234
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• 1980

Deep-fried instant noodle was prepared on a laboratory scale (150 units). A part of the noodle was packed in gas-proof laminated film bags with a small package of an oxygen scavenger made from Fe-powder and a 150 ml of air in each bag(Sample 1). Another part was packed in ordinary laminated film bags (Control), and the rest was vacuum-packed (74 mmHg) in the gas-proof film bags (Sample 2). All samples were placed in an incubator kept at $45.0{\pm}0.5^{\circ}C$ for 45 days. Oxygen-removing power of the scavenger, and peroxide and thiobarbituric acid values of the samples were determined regulary. The results of the study are as follows: 1. The residual oxygen concentration of the bags in Sample 1 decreased from the original 21% to less than 0. 5% after 48 hr. 2. POVs of Control, Samples 1 and 2 after 45 days were $12.4{\pm}0.4$, $5.7{\pm}0.2$ and $6.8{\pm}0.1\;meq/㎏$ fat respectively. It was noteworthy that the POV of Sample 1 did not change significantly during the storage period. The scavenger seemed very effective in retarding the POV development of Sample 1. 3. TBA values of Control, Sample 1 and 2 after 45 days were $1.31{\pm}0.04$, $0.60{\pm}0.04$, and $0.72{\pm}0.07$. As in the case of POVs, the samples packed with the scavengers exhibited consistently smaller TBA values than the vacuum-packed samples in later stages of the storage period.

• Ocean and Polar Research
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• v.36 no.2
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• pp.135-143
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• 2014

The effect of salinity on the survival, oxygen consumption and blood physiology of Korean rockfish Sebastes schlegelii (body weight $97.4{\pm}1.7g$, $mean{\pm}SD$) was investigated at nine different salinities of 33.4 (control), 33.1, 32.8, 32.2, 31.0, 28.7, 23.9, 14.5 and 3.8 psu, respectively. Survival and blood physiology were measured at each salinity in two separate trials of 96 and 24 hr duration, respectively. Oxygen consumption rate (OCR) was determined at stepwise salinity exposure ($33.4{\rightarrow}33.1{\rightarrow}32.8{\rightarrow}32.2{\rightarrow}31.0{\rightarrow}28.7{\rightarrow}23.9{\rightarrow}14.5{\rightarrow}3.8$ psu) with an interval of 24 hr for each salinity. No death of fishes were observed in the range of 33.4 to 14.5 psu, but the survival rate was reduced to 26.7% at 3.8 psu after 96 hr. The OCRs were not significantly different in the range 33.4 to 28.7 psu (p > 0.05), but significantly increased until 14.5 psu and then drastically decreased at 3.8 psu compared to the control (p < 0.05). The concentrations of plasma $Na^+$ and $Cl^-$ were significantly lower in fish exposed at 3.8 psu compared to the control (p < 0.05). The results of this study provide evidence that S. schlegelii exposed to concentrations below 23.9 psu show significant physiological responses to tolerate salinity changes under the experimental conditions we established.

• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.6
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• pp.498-502
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• 2015

Yukmijihwang-tang (YM) is a well-known prescription to treat kidney inflammation on Korea. However, the effects of YM on maximal exercise performance (MEP) is not-well investigated. In this study, we aimed to evaluate the effects of YM on MEP using forced swimming test (FST) model. Mice were largely divided into three group; a non-swimming group, saline treated-swimming load test group, and YM treated-swimming load group. Swimming load test groups were re-divided into swimming control group (Control), YM fed group (YM). YM was administrated orally for 2 weeks before FST. After FST, immobility time, oxygen consumption was measured by physiological test, and serum was collected for biochemical analysis. FST induced MEP identified by increased immobility, oxygen consumption, and biochemical factors. Immobility time was significantly reduced by YM treatment compared with control group. Oxygen consumption was also significantly reduced by YM treatment. The increase on lactic acid and lactate dehydrogenase after FST was inhibited by YM　treatment. In addition, consumption of energy source (free fatty acid, and triglyceride) and recovery of energy was enhanced by YM treatment after FST. In conclusion, YM inhibited the elevation of immobility time, oxygen consumption, and biochemical factors after FST. YM could be used as a beneficial agents to enhance maximal endurance exercise performance and an effective ergogenic aid in exercise training.