• 한국세라믹학회지
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• 제36권12호
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• pp.1335-1341
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• 1999

The electrical conductivity ($\sigma$) of TiO2 doped with 0.05-4.0mol% Nb2O5 was measured in the oxygen partial pressure range of 10-17 to 100 atm and temperature range of 1100 to 130$0^{\circ}C$ to investigate the electrical properties and defect types. The oxygen partial pressure dependence of the electrical conductivity (log$\sigma$/logPo2) above 110$0^{\circ}C$ was divided into the four regions. From these experimental results the following defect regions were proposed ; 1) Magneli phase(extended defect) 2) reduced rutile region where intrinsic defect predominates 3) nearly stoichiometric region which is independent on the oxygen partical pressure and 4) overstoichiometric region which is not observed in pure TiO2 The electrical conductivity of Nb-doped TiO2 depended on the doping content the oxygen partial pressure and the measuring tem-perature.

• Journal of Welding and Joining
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• 제12권1호
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• pp.94-101
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• 1994

In this study, plasma spraying has been used to produce $TiO_2$ polycrystalline coatings from $TiO_2$ powders. The physical and chemical properties of plasma sprayed $TiO_2$ coatings depend greatly on plasma spraying conditions. The electrical resistivity, oxygen concentration, photocurrent and crystal structure of plasma sprayed $TiO_2$ coating has been studied. The results are as follows: 1. The oxygen loss and electrical conductivity of $TiO_2$ plasma sprayed coatings increased by low pressure and high amount of auxiliary gas, hydrogen in plasma spraying. 2. Oxygen loss increase electrical conductivity, and decrease photocurrent of $TiO_2$ plasma sprayed coatings. 3. Photocurrent of $TiO_2$ plasma sprayed coatings manufactured in atmospheric pressure is higher than that of low pressure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.85-88
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• 2001

The NdBaCuO superconductor samples were Zone-melted in low oxygen partial pressure (1% O$_2$+99% Ar). The Zone-melting temperature was decreased about 120$^{\circ}C$ from 1060$^{\circ}C$ the zone-melting temperature in air. Thus the loss of liquid phase (BaCuO$_2$ and CuO) was reduced during the zone-melting process. The content of non-superconducting phase Nd422 in zone-melted NdBaCuO samples was clearly decreased, so was the substitution of Nd for Ba. The superconductivity of zone-melted Nd$\sub$1+x/Ba$\sub$2-x/Cu$_3$O$\sub$y/ prepared under low oxygen partial pressure was distinctively improved.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.263-266
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• 2003

The fine $YBa_2Cu_3O_x$ powder ($0.2{\sim}1.0\;{\mu}m$) is produced by sol-gel method, and electrophoresis deposition is used for the preparation of $YBa_2Cu_3O_x$ thick films which are deposited on Ag wire. The oriented $YBa_2Cu_3O_x$ was tried to be prepared by the zone-melting method under low oxygen partial pressure. The orientation and the phase composition were examined by the X-ray diffraction and the superconductivities were measured by 4 line method. The critical current densities are still quite low, which may be due to unsuitable technical parameters for zone-melting of $YBa_2Cu_3O_x$ thick films. Therefore the heat treatment condition and controlling of low oxygen partial pressure should be improved in the future experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제26권6호
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• pp.679-687
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• 2002

In this study, a cycle simulation using a two-zone model is carried out to investigate the effect of intake charging conditions such as oxygen concentration, temperature and pressure on NO emissions in a DI diesel engine. The model is validated against measurements in terms of cylinder pressure, torque, BSFC and NOx emissions with 2902 cc DI diesel engine. Calculated results can be summarized as follows. The oxygen concentration in the intake charge is decreased with increasing of EGR rate and equivalence ratio. As the intake oxygen concentration is reduced, the combustion pressure and the burned gas temperature decrease and, as a result, NO formation decreases. Also, the results show that as the intake pressure increases and the intake temperature decreases, NO emissions are effectively reduced.

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.59-63
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• 2009

This paper presents two dimensional simulation results of an inductively coupled $Ar/O_2$ plasma reactor. The effects of operating conditions on the plasma properties and the uniformity of atomic oxygen near the wafer were systematically investigated. The plasma density had the linear dependence on the chamber pressure, the flow rate of the feed gas and the power deposited into the plasma. On the other hand, the electron temperature decreased almost linearly with the chamber pressure and the flow rate of the feed gas. The power deposited into the plasma nearly unaffected the electron temperature. The simulation results showed that the uniformity of atomic oxygen near the wafer could be improved by lowering the chamber pressure and/or the flow rate of the feed gas. However, the power deposited into the plasma had an adverse effect on the uniformity.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.419-420
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• 2010

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.101-101
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• 2008

The effect of oxygen partial pressure on the surface tension data of liquid alloys was investigated by means of comparing the calculated data and the measured one. Two binary alloy systems were chosen to observe the dependence of oxygen adsorption behavior on different oxygen partial pressures. It was found that the difference between the computed values and the experimental of the surface tension was within the range of maximum 10%.

• 한국가스학회지
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• 제27권3호
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• pp.84-90
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• 2023

연소의 3요소 중 대기 중에 상시 존재하는 산소는 고압산소 조건에서는 극미량의 가연물만으로도 화재·폭발이 발생할 수 있으며. 연소속도 역시 상당하여 순식간에 공정 설비 및 배관을 녹이는 등 직접적인 영향을 줄 수 있는 온도까지 상승할 수 있다. 따라서 고압산소 상태에서 발생한 사고는 기타 사고에 비해 큰 피해가 발생하는 경우가 많다. 최근 산소공급 배관에 설치되어 있는 밸브를 조작하던 도중 내부에서 급격한 연소와 함께 파열이 발생하여 폭발로 인한 인명피해가 발생하였는데, 오래된 탄소강 배관인 경우 운전 중 발생한 Particle이 가연물이 되어 사고가 발생할 수 있다. 특히나 산소설비는 고압가스안전관리법에 따라 허가된 시설이고, 산업안전보건법에 의한 제한규정이 없는 상태이기 때문에 이러한 기준 적립이 무엇보다 중요하다. 따라서 본 연구에서는 사고사례 및 해외기준을 바탕으로 고압 산소 취급 시 안정성 향상을 위한 방법에 대해 검토하고자 한다.

• 대한기계학회논문집B
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• 제21권9호
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• pp.1174-1184
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• 1997

Extinction characteristics of pure hydrogen-oxygen diffusion flames, at high pressures in the neighborhood of the critical pressure of oxygen, is numerically studied by employing counterflow diffusion flame as a model flame let in turbulent flames in rocket engines. The numerical results show that extinction strain rate increases almost linearly with pressure up to 100 atm, which can be explained by comparison of the chain-branching-reaction rate with the recombination-reaction rate. Since contributions of the chain-branching reactions, two-body reactions, are found to be much greater than those of the recombination reactions, three-body reactions, extinction is controlled by two-body reactions, thereby resulting in the linearity of extinction strain rate to pressure. Therefore, it is found that the chemical kinetic behaviors don't change up to 100 atm. Consideration of the pressure fall-off reactions shows a slight increase in extinction strain rate, but does not modify its linearity to pressure. The reduced kinetic mechanisms, which were verified at low pressures, are found to be still valid at high pressures and show good qualitative agreement in prediction of extinction strain rates. Effect of real gas is negligible on chemical kinetic behaviors of the flames.