• Carbon letters
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• v.1 no.1
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• pp.17-21
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• 2000

Catalytic reduction and oxidation of NO over polyacrylonitrile based activated carbon fibers (PAN-ACF) under various conditions were carried out to develop removal process of NO from the flue gas. The effect of temperature, oxygen concentration and the moisture content for the reduction of NO with ammonia as a reducing agent was investigated. The reduction of NO increased with the oxygen concentration, but decreased with the increased temperature. The moisture content in the flue gas affects the reduction of NO as the inhibition of the adsorption of the other components and the reaction on the surface of ACE For the oxidation of NO to $NO_2$ over PAN-ACF without using a reducing gas, it showed the temperature and the oxygen concentration of the flue gas are the important factors for the NO conversion in which the conversion increased with oxygen concentration and decreased with the temperature increase and might be the alternative option for the selective catalytic reduction process.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.814-815
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• 2006

The removal of oxygen during sintering by carbothermic reduction was studied for steel compacts Fe-Cr-Mo-C and Fe-Mo-C prepared from prealloyed powders. The compacts were prepared by pressing at 600 and 1000 MPa and sintering at 1100 and $1300^{\circ}C$ in vacuum. It showed that for the Cr-Mo steel, deoxidation strongly depends on the sintering temperature, in contrast to the plain Mo steel; at $1300^{\circ}C$ very low oxygen levels were measured with the standard density compact while at high density still significant oxygen is contained. This indicates inhibition of final deoxidation by pore closure, but apparently without adverse effect on the mechanical properties.

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.183-188
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• 1998

Incorporation of metalloporphyrins into polypyrrole (PPy) film was achieved either by electropolymerization of pyrrole in the presence of metal-tetra(sulfonatophenyl)porphyrin anion (MTSPP, M=Co, Fe) or by metalizing hydrogenated tetra(4-sulfonatophenyl)porphyrin anion (H2TSPP) doped into PPy through ion-exchange. Electrochemical reduction of oxygen on the PPy doped with metallo porphyrin (PPy-MTSPP) was studied in acidic and basic solutions. Oxygen reduction on PPy-MTSPP electrodes appeared to proceed through a 4-electron pathway as well as a 2-electron path. In acidic solutions, the overpotential for O2 reduction on PPy-CoTSPP electrode was smaller than that on gold by about 0.2 V. In basic solutions the overpotential of the PPy-CoTSPP electrode in the activation range was close to those of Au and Pt. The limiting current was close to that of Au. However, polypyrrole doped with cobalt-tetra(sulfonatophenyl)porphyrin anion (PPy-CoTSPP) or with iron-tetra(sulfonatophenyl)porphyrin anion (PPy-FeTSPP) was found to have limited potential windows at high temperatures (above 50 ℃), and hence the electrode could not be held at the oxygen reduction potentials in basic solutions (pH 13) without degradation of the polymer.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1691-1698
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• 1989

Gas sensing effects produced by adsorptive reaction between specimen surface and gases are expected to be influenced greatly by the state of the speimen surface. In this study, Co1-xMgxO ceramics oxygen sensors were prepared by pressing at 0.3-1.5ton/cm\ulcornerwith or without binder, intending to change porosity and average grain size on the surface purposely. The composition ratio of CoO to MgO was fixed at 1:1(mol.%). Microstructure of prepared Co0.5Mg0.5O ceramics were observed, the electrical properties and the sensitivity characteristics for oxygen gas were investigated in the device temperature range of 700-1000\ulcorner and for oxygen partical pressure range of 1-10**-4 atm. Temperature dependence of the resistivity of the specimen showed NTC behavior, average grain size increased and porosity decreased with increasing compaction pressure. The slope of the resistivity of the specimen on the oxygen partial pressure decreased with increasing average grain size and with decreasing porosity. Particularly, specimen pressed by 0.3 and 0.5 ton/cm\ulcornershowed the highest sensitivity to oxygen gas.

• Physical Therapy Rehabilitation Science
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• v.11 no.1
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• pp.58-65
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• 2022

Objective: The purpose of this study was to investigate the effect of visual feedback bicycle training on running performance, maximal oxygen uptake and quadriceps muscle strength. Design: A randomized controlled trial. Methods: Fifteen healthy adult men with no musculoskeletal or nervous system disease and capable of bicycle training were included. After the pretest, subjects were randomly assigned to visual feedback bicycle training group and general fixed bicycle training group. Both groups were trained two times a week for three weeks, each week for a fixed time and number of repetitions, followed by a six week washout period and then crossing the training method. visual feedback bicycle training provides visual feedback of heart rate in real time using a monitor and a heart rate meter during bicycle training, and general fixed bicycle training performed general bicycle training without visual feedback. After training, each item was measured using a wearable technology, gas analyzer, isokinetic equipment. Results: The results of this study was significant differences in running performance, maximal oxygen uptake and quadriceps muscle strength in visual feedback bicycle training group (p<0.05). The differential effect was found between visual feedback bicycle training group and general fixed bicycle training group in running performance, maximal oxygen uptake, and quadriceps muscle strength (p<0.05). Conclusions: This study suggested that that visual feedback bicycle training can be applied as a useful training method to improve running performance, maximal oxygen uptake and quadriceps muscle strength.

• Tuberculosis and Respiratory Diseases
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• v.81 no.4
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• pp.319-329
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• 2018

Background: Bronchoalveolar lavage (BAL) is a necessary procedure for diagnosis of various lung diseases. High-flow nasal cannula (HFNC) oxygen delivery was recently introduced. This study aimed to investigate the safety and effectiveness of HFNC oxygen supply during BAL procedure in patients with acute respiratory failure (ARF). Methods: Patients who underwent BAL while using HFNC at a partial pressure of oxygen in arterial blood/fraction of inspired oxygen ($PaO_2/FiO_2$; PF) ratio of 300 or below among patients who had been admitted from March 2013 to May 2017 were retrospectively investigated. Results: Thirty-three BAL procedures were confirmed. Their baseline PF ratio was $166.1{\pm}46.7$. $FiO_2$ values before, during, and after BAL were $0.45{\pm}0.12$, $0.74{\pm}0.19$, and $0.57{\pm}0.14$, respectively. Flow (L/min) values before, during, and after BAL were $26.5{\pm}20.3$, $49.0{\pm}7.2$, and $40.8{\pm}14.2$, respectively. Both $FiO_2$ and flow during and after the procedure were significantly different from those before the procedure (both p<0.001). Oxygen saturation levels before, during, and after BAL measured by pulse oximeter were $94.8{\pm}2.9$, $94.6{\pm}3.5$, and $95.2{\pm}2.8%$, respectively. There were no significant differences in oxygen saturation among the three groups. Complications of BAL procedure included transient hypoxemia, hypotension, and fever. However, there was no endotracheal intubation within 24 hours. Baseline PF ratio in "without HFNC" group was significantly higher than that in "with HFNC" group. There were no differences in complications between the two groups. Conclusion: The use of HFNC during BAL procedure in ARF patients was effective and safe. However, there were no significant differences in oxygen saturation level and complications comparing "without HFNC" group in mild ARF. More studies are needed for moderate to severe ARF patients.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.6
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• pp.498-504
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• 2004

Removal of waste generated by Paralichthys olivaceus in the seawater aquarium using a foam separator was investigated. Protein concentration without a foam separator continuously increased until 3 days after stocking and reached at 25 mg/L after 5 days stocking, but protein concentration became lower than the initial protein concentration (2.5 mg/L) with a foam separator. The trends of other fish wastes such as ammonia, total suspended solids (TSS) and chemical oxygen demand (COD) were similar to protein. Dissolved oxygen (DO) in the aquarium decreased below 6.0 mg/L without a foam separator, but with a foam separator the average DO in the aquarium was 7.3 mg/L. Foam separation with the increase of superficial air velocity (SAV) was more effective than that with the fixed SAV. This study showed that wastewater. treatment of seawater aquarium using a foam separator is effective method for a fish waste removal and oxygen supply.

• Food Science and Biotechnology
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• v.18 no.2
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• pp.413-418
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• 2009

Effects of chlorophyll and visible light exposure on the volatile formations and headspace oxygen content were studied in lard model systems at $55^{\circ}C$. Samples with or without addition of chlorophyll under light underwent photosensization or photooxidation, respectively. Total volatiles (TI) in lard with 5 ppm chlorophyll photosensization were 19 times higher than those in visible light photooxidized samples for 48 hr while TI in lard with chlorophyll in the dark were not significantly different from those in photooxidized samples (p>0.05). Headspace oxygen content in photosensitized lard decreased from 21 to 15% for 48 hr but that in photooxidized lard or that in lard with chlorophyll in the dark did not change significantly (p>0.05), which indicates that lard system used in this study is a photosensitizer-free model system and the presence of chlorophyll accelerated the lipid oxidation only under visible light. Oxidation mechanisms of photooxidation with or without presence of photosensitizers under visible light were not the same based on the difference of oxidized volatile profiles and headspace oxygen depletion.

• Journal of Embryo Transfer
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• v.32 no.1
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• pp.9-15
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• 2017

The present study was aimed to determine the effect of green tea extract (GTE) and beta-mercaptoethanol (${\beta}$-ME) supplementation in boar sperm freezing extender on sperm motility, viability and reactive oxygen species (ROS) level. Experimental groups were allocated into Lactose-egg yolk (LEY) without antioxidant (control), GTE (1,000 mg/L GTE in LEY) and ${\beta}$-ME ($50{\mu}M$ ${\beta}$-ME in LEY). Spermatozoa extended with LEY were cooled to $5^{\circ}C$ for 3 h and then kept at $5^{\circ}C$ for 30 min following dilution with LEY containing 9% glycerol and 1.5% Equex STM (final sperm concentration: $1{\times}10^8/mL$). Spermatozoa were loaded into straws and frozen in nitrogen vapor for 20 min. Following thawing at $37^{\circ}C$ for 25 sec, sperm viability and ROS level were measured using fluorescent double stain Fertility(R) and cytometry, respectively. Motility and viability of GTE supplemented-group were higher than those of control and ${\beta}$-ME without significance. ROS level in GTE group showed significantly lower than control (P < 0.05). In conclusion, GTE supplementation in boar sperm freezing extender can reduce ROS generation during freezing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.885-888
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• 2000

The effects of deposition temperature and post annealing process of ferroelectric PbZr$\sub$0.52/Ti$\sub$0.48/O$_3$(PZT) thin films by pulsed laser deposition (PLD) were investigated. The PZT thin films were deposited at 400, 450, 500, and 550$^{\circ}C$, with/without post annealing at 650$^{\circ}C$ for 30 min. The PZT thin films deposited above 500$^{\circ}C$ without post annealing were crystallized into peroveskite phase, but the PZT thin films deposited below 450$^{\circ}C$ had pyrochlore phase. The PZT thin films deposited below 450$^{\circ}C$ with post annealing also crystallized into pure perovskite. Compared to the PZT thin films which were deposited at 450$^{\circ}C$ and post annealed, the films deposited at 550$^{\circ}C$ have a columnar microstructure and high remnant polarization 28 (${\mu}$C/cm$^2$). With in-situ annealing at oxygen ambient, the PZT thin films reduced oxygen vacancies and increased retained polarization.