• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.852-857
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• 2017

In this paper, measurements of ion mobility were performed in oxygen at gas pressures of 44.52 - 101.19 kPa using the drift tube method. Over this pressure range, mobility values were within the limits of 1.796 to $3.821cm^2{\cdot}V^{-1}{\cdot}s^{-1}$ were determined and ion mobility shown to decrease non-linearly with increasing gas pressure towards a certain level of saturation. Ion mobility measured in air was lower than that measured in oxygen at the same gas pressure. Finally, a parameter correction method for calibrating the relationship between the ion mobility and gas pressure in oxygen was proposed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.8
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• pp.846-851
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• 2004

Transparent conducting indium tin oxide (TC-ITO) thin films on polymeric substrates have been deposited by a dc reactive magnetron sputtering without heat treatments. The polymeric substrates are acryl (AC), poly carbornate (PC), and polyethlene terephthalate (PET) as well as soda lime glass is also used to compare with the polymeric substrates. Sputtering parameters are an important factor for high quality of TC-ITO thin films prepared on polymeric substrates. Furthermore, the material, electrical and optical properties of as-deposited ITO films are dominated by the ratio of oxygen partial pressure. As the experimental results, the surface roughness of ITO films becomes rough as the oxygen partial pressure increases. The electrical resistivity of as-deposited ITO films decreases initially, and then increases with the increase of oxygen partial pressure. The optical transmittance at visible wavelength for all polymeric substrates is above 82 %.

• Journal of the Korean Ceramic Society
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• v.27 no.7
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• pp.841-850
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• 1990

The electrical conductivity of SrTiO3 thick films, which has been prepared by screen printing and sintering on polycrystalline Al2O3 substrates, was determined as a function of oxygen partial pressure and temperature. The data showed that electrical conductivity was proportional to the -1/4th power of the oxygen partial pressure for the oxygen partial pressure range from 10-4-10-8 to 10-20 atm and proportional to Po2+1/4 for the oxygen partial pressure range from 10-6-10-4 to 1atm. And then n-p transition region of electrical conductivity moved to lower oxygen partial pressure region as the sintering temperature of thick film specimens increased under about 140$0^{\circ}C$. These data were consistent with the presence of small amounts of acceptor impurities in SrTiO3 thick film which have been diffused from Al2O3 substrate in the range of solid solubility limit.

• Bulletin of the Korean Chemical Society
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• v.18 no.6
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• pp.640-643
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• 1997

Pure titanium dioxide $(TiO_2)$ films were prepared by pulsed laser deposition on a single crystal Si(100) substrate. We have investigated the growth of crystalline titanium dioxide films with respect to substrate temperature and ambient oxygen pressure. The structural properties of the films were analyzed by X-ray diffraction. We found that the anatase as well as the rutile phases could be formed from the original rutile phase of the target $TiO_2$. At 0.75 torr of ambient oxygen pressure, the structure of $TiO_2$ film was amorphous at room temperature, anatase between 300 and 600 ℃, a mixture of anatase and rutile between 700 and 800 ℃, and only rutile at 900 ℃ and above. However, at a low ambient oxygen pressure, the rutile phase became dominant; the only rutile phase was obtained at the ambient oxygen pressure of 0.01 torr and the substrate temperature of 800 ℃. Therefore, the film structures were largely influenced by substrate temperature and ambient oxygen pressure.

• Journal of Powder Materials
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• v.28 no.6
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• pp.478-482
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• 2021

The effect of the process conditions of high-velocity oxygen fuel (HVOF) thermal spray coating on the porosity of the coating layer is investigated. HVOF coating layers are formed by depositing amorphous FeMoCrBC powder. Oxygen pressure varies from 126 to 146 psi and kerosene pressure from 110 to 130 psi. The Microstructural analysis confirms its porosity. Data analysis is performed using experimental data. The oxygen pressure-kerosene pressure ratio is found to be a key contributor to the porosity. An empirical model is proposed using linear regression analysis. The proposed model is then validated using additional test data. We confirm that the oxygen pressure-kerosene pressure ratio exponentially increases porosity. We present a porosity prediction model relationship for the oxygen pressure-kerosene pressure ratio.

• Journal of the Semiconductor & Display Technology
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• v.9 no.4
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• pp.77-81
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• 2010

The AZO thin films were deposited on the corning 1737 glass plate by the RF magnetron sputtering and effects of working pressure and oxygen contents on the electrical properties were investigated. XRD spectra showed a preferred orientation along the c-axis and a minimum FWHM for the 70mTorr. From the surface analysis (AFM), the number of crystal grain of AZO thin film increased as working pressure increased. The film deposited with 70mTorr of working pressure showed n-type semiconductor characteristic having suitable resistivity $-1.59{\times}10^{-2}{\Omega}cm$, carrier concentration $-10.1{\times}10^{19}cm^{-3}$, and mobility $-4.35cm^2V^{-1}s^{-1}$ while other films by 7 mTorr, 20 mTorr of working pressure closed to metallic films. The films including the oxygen represent stoichiometric composition similar to the oxide. The transmittance of the film was over 85% in the visible light range regardless of the changes in working pressure and oxygen contents.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.13-17
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• 2009

A semi-empirical method to estimate the surface tension of molten alloys at different oxygen partial pressures is suggested in this study. The surface tension of molten Ag-Sn and Ag-Cu alloys were calculated using the Butler equation with the surface tension value of pure substance at a given oxygen partial pressure. The oxygen partial pressure ranges were $2.86{\times}10^{-12}$－$1.24{\times}10^{-9}$ Pa for the Ag-Sn system and $2.27{\times}10^{-11}$－$5.68{\times}10^{-4}$ Pa for the Ag-Cu system. In this calculation, the interactions of the adsorbed oxygen with other metallic constituents were ignored. The calculated results of the Ag-Sn alloys were in reasonable accordance with the experimental data within a difference of 8%. For the Ag-Cu alloy system at a higher oxygen partial pressure, the surface tension initially decreased but showed a minimum at $X_{Ag}$ = 0.05 to increase as the silver content increased. This behavior appears to be related to the oxygen adsorption and the corresponding surface segregation of the constituent with a lower surface tension. Nevertheless, the calculated results of the Ag-Cu alloys with the present model were in good agreement with the experimental data within a difference of 10%.

• Journal of Convergence for Information Technology
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• v.8 no.3
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• pp.71-77
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• 2018

In this paper, considering the oxygen sensitivity and preference pattern of the patient, the profile of the oxygen therapy of the individual is specified. And, we design a three-compartment, single compartment oxygen chamber that automatically adjusts the oxygen pressure according to the specified profile. Hyperbaric oxygen therapy is a method of providing patients with 100% oxygen higher than atmospheric pressure for therapeutic purposes. However, there is a disadvantage that the ear pain is caused by the pressure difference depending on the individual. Based on the embedded system, the proposed system creates a patient-tailored oxygen therapy profile by DB of patient's preference patterns and treatment records of oxygen therapy. If only the patient's name is entered, the oxygen chamber system can adjust the oxygen pressure automatically according to the profile pattern to maximize the oxygen treatment effect.

• Journal of Environmental Science International
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• v.4 no.3
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• pp.259-267
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• 1995

This study was conducted to evaluate the effects of pressure and dissolved oxygen concentration on the activated slut비e and to determine the optimum depth of deep shaft process. Some results from this study were summarized as follows. 1. It is considered that low sludge product in the activated sludge system maintaining high dissolved oxygen concentration is attributed to the increase of endogeneous respiration rate caused by the increase of aerobic zone in the sludge floe. 2. The increase of dissolved oxygen concentration does not affect to the increase of organic removal efficiency greatly and therefore the limiting factor is the substrate transfer into the inner part of floe. 3. The yield coefficient, Y is decreased in proportion to the increase of oxygen concentration. In this study, Y values arre ranged from 0.70 to 0.41 according to the variation of dissolved oxygen concentration from 18.0mg/$\ell$ to 258 mg/$\ell$. 4. The optimum depth of deep shaft process should be determined within the limits of non-toxicity to the microorganism and it is about loom in this study.

• Korean Chemical Engineering Research
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• v.58 no.4
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• pp.610-617
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• 2020

In process installations, chemicals operate at high temperature and high pressure. Propylene is used as a basic raw material for manufacturing synthetic materials in the petrochemical industry; However, it is a flammable substance and explosive in the gaseous state. Thus, caution is needed when handling propylene. To prevent explosions, an inert gas, carbon dioxide, was used and the changes in the extent of explosion due to changes in pressure and oxygen concentration at 25 ℃, 100 ℃, and 200 ℃ were measured. At constant temperature, the increase in explosive pressure and the rates of the explosive pressure were observed to rise as the pressure was augmented. Moreover, as the oxygen concentration decreased, the maximum explosive pressure decreased. At 25 ℃ and oxygen concentration of 21%, as the pressure increased from 1.0 barg to 2.5 bar, the gas deflagration index (K_g) increased significantly from 4.71 barg·m/s to 18.83 barg·m/s.