• 한국진공학회지
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• 제8권4B호
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• pp.507-513
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• 1999

8mol%-yttria-stabilized zirconia(YSZ) thin films as oxygen ion conductor were deposited by rf-magnetron sputtering, and the oxygen gas sensors with the structure of $SiO_2$ substrate/Ni-NiO mixed reference layer/Pt/YSZ/Pt were fabricated and their oxygen sensing properties were investigated. The steady-state electro-motive force (EMF) values were measured as a function of oxygen partial pressure ($PO_2;form 1.013\times10^3 \textrm{Pa \;to}\; 1.013\times10^5$Pa) and operating temperature ($300^{\circ}C$ to $700^{\circ}C$). The fabricated YSZ oxygen sensor showed the best oxygen sensing properties at 50$0^{\circ}C$. However, oxygen sensing properties were very low at the temperature lower than 30$0^{\circ}C$ due to the lack of oxygen ion mobility and at the temperature higher than $700^{\circ}C$ due 새 intermixing of materials between the layers. Especially, the YSZ sensor operating at $500^{\circ}C$ and oxygen partial pressure above $1.565\times10^4$Pa showed the oxygen sensing properties close to the values predicted by ideal Nernst equation.

• 한국재료학회지
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• 제17권6호
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• pp.303-307
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• 2007

ZnO thin films were prepared by pulsed laser deposition on amorphous fused silica substrates at different ambient $O_2$ pressures varying from 0.5 to 500 mTorr, to observe the effect of ambient gas on their crystalline structure, morphology and optical properties. Results of X-ray diffraction, scanning electron microscopy, atomic force microscopy and photoluminescence studies showed that crystallinity, surface features and optical properties of the films significantly depended on the oxygen background pressure during growth. A low oxygen pressure (0.5 mTorr) seems to be suitable for the growth of highly c-axis oriented and smoother films possessing a superior luminescent property. The films grown at the higher $O_2$ pressures (50-500 mTorr) were found to have many defects probably due to an excessive incorporation of oxygen into ZnO lattice. We speculate that the film crystallinity could be affected by the kinetics of atomic arrangement during deposition at the higher oxygen pressures.

• Journal of Microbiology
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• 제44권4호
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• pp.466-471
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• 2006

In this study, we attempted to characterize the biomolecular effects of an atmospheric-pressure cold plasma (APCP) system which utilizes helium/oxygen $(He/O_2)$. APCP using $He/O_2$ generates a low level of UV while generating reactive oxygen radicals which probably serve as the primary factor in sterilization; these reactive oxygen radicals have the advantage of being capable to access the interiors of the structures of microbial cells. The damaging effects of plasma exposure on polypeptides, DNA, and enzyme proteins in the cell were assessed using biochemical methods.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1993년도 추계 학술발표 강연 및 논문 개요집
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• pp.69-71
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• 1993

Fluoride compound potentiometric cell oxygen sensors were fabricated for the measurement of oxygen pressure in the low temperature range (300。K-500。K). The disk type sensors consist of a reference Air(0$_2$):Ag, a solid electrolyte SrF$_2$, and a sensing metel Ag electrode. And the buried reference electrode type sensor have a NiO/Ni reference electrode. The open circuit emf of the cell showed high sensivity to oxygen gas (60mv) at the measuring temperature 20$0^{\circ}C$. Also, The buried reference electrode type sensor showed 30mv from 1% to 10% oxygen pressure range.

• Bulletin of the Korean Chemical Society
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• 제20권3호
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• pp.281-284
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• 1999

Two La1.82Ca1.18Cu2O6+δ (2126) compounds exhibited different properties depending upon how they were synthesized. The compound prepared under high oxygen pressure showed superconductivity. But the compound prepared under low oxygen pressure did not exhibit superconductivity, and showed a metal-insulator transition. Our study on these compounds shows that a small amount of additional oxygen intercalated into the superconducting phase plays an important role for superconductivity. The Fermi surface of non-superconducting 2126 compound possesses nesting phenomena, which is the reason for the M-1 transition. On the other hand, the superconducting 2126 compound does not show Fermi surface nesting. This is because the additional oxygen removes some electrons from Cu d-orbitals, thereby bradking the Fermi surface nesting.

• 한국수소및신에너지학회논문집
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• 제8권2호
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• pp.79-90
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• 1997

Extensive work has been done on investigating the inner cell pressure characteristics of sealed type Ni-MH battery in which Zr-Ti-Mn-V-Ni alloy is used as anode. The inner cell pressure of this type Ni-MH battery much more increases with the charge/discharge cycling than that of the other type Ni-MH battery where commercialized $AB_5$ type alloy is used as anode. The increase of inner cell pressure in the sealed type Ni/MH battery using Zr-Ti-Mn-V-Ni alloy system is mainly due to the accumulation of oxygen gas during charge/discharge cycling. The accumulation of oxygen gas arises mainly due to the low rate of oxygen recombination on the MH electrode surface during charge/discharge cycling. The difference of oxygen recombination rate between $AB_5$ type electrode and Zr-Ti-Mn-V-Ni electrode is caused by the difference of electrode reaction surface area resulting from different particle size after their activation and the difference of surface catalytic activity for oxygen recombination reaction, respectively. After EIS analysis, it is identified that the surface catalytic activity affects much more dominantly on the oxygen recombination reaction than the reaction surface area does. In order to suppress the inner cell pressure of Ni-MH battery where Zr-Ti-Mn-V-Ni is used as anode, it is suggested that the surface catalytic activity for oxygen recombination should be improved.

• 한국전기전자재료학회논문지
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• 제16권9호
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• pp.775-782
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• 2003

In the study, the total conductivies in [(Ce $O_2$)$_{1-x}$ (Zr $O_2$)$_{x}$]$_{0.8}$(Sm $O_{1.5}$)$_{0.2}$ (x- 0, 0.05, 0.1, 0.2) solid solution were measured as a function of temperature and oxygen partial pressure between 80$0^{\circ}C$ and 1,00$0^{\circ}C$ using 4-probe d.c method. Under pure oxygen atmospere, the oxygen ionic conductivity of [(Ce $O_2$)$_{1-x}$ (Zr $O_2$)$_{x}$]$_{0.8}$(Sm $O_{1.5}$)$_{0.2}$ decreased with the concentration of Zr $O_2$At high oxygen partial pressure, the electrical conductivity is almost independent of oxygen partial pressure and decreased with the increase in Zr content. However, the electrical conductivity increase with decreasing oxygen partial pressure and is almost independent of Zr content at low oxygen partial pressure. Empirically, Total conductivity( $\sigma$ ) was expressed by the p$o_{2}$ -independent conductivity as $\sigma$$_{i}$, and the $p_{-1/4}$ $o_{2}$sup -dependent part as $\sigma$$_{e}$. Total, ionic and electronic conductivities fitted by data enabled to determine the transference number. The ionic transference number( $t_{i}$ ) decreased while the electronic transference( $t_{e}$ ) increase with the increase in Zr content and p$o_{2}$.

• Corrosion Science and Technology
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• 제12권2호
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• pp.85-92
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• 2013

This work is concerned with an evaluation of dynamic boric acid corrosion (BAC) of low alloy steel for reactor pressure vessel of a pressurized water reactor (PWR). Mockup test method was newly established to investigate dynamic BAC of the low alloy steel under various conditions simulating a primary water leakage incident. The average corrosion rate was measured from the weight loss of the low alloy steel specimen, and the maximum corrosion rate was obtained by the surface profilometry after the mockup test. The corrosion rates increased with the rise of the leakage rate of the primary water containing boric acid, and the presence of oxygen dissolved in the primary water also accelerated the corrosion. From the specimen surface analysis, it was found that typical flow-accelerated corrosion and jet-impingement occurred under two-phase fluid of water droplet and steam environment. The maximum corrosion rate was determined as 5.97 mm/year at the leakage rate of 20 cc/min of the primary water with a saturated content of oxygen within the range of experimental condition of this work.

• 한국가스학회지
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• 제9권1호
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• pp.38-43
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• 2005

도시가스의 폭발특성을 평가하기 위하여, 산소의 농도와 초기압력의 변화에 따라 실험을 행하였다 이러한 실험을 행한 결과 산소농도가 낮아짐에 따라 폭발범위는 점차적으로 좁혀졌으며, 산소농도 $12\%$에서 폭발한계산소농도를 구하였다. 도시가스의 초기압력이 증가함에 따라 폭발하한계가 약간 증가하였다. 또한 초기압력이 $0{\~}1.0 kgf/cm^2{\cdot}g$로 변함에 따라 최대폭발압력은 $6.3 kgf/cm^2{\cdot}g,\;12.7 kgf/cm^2{\cdot}g$을 구하였으며, 최대폭발압력상승속도는 $245.63 kgf/cm^2/s,\;427.88 kgf/cm^2/s$를 구하였다.

• 반도체디스플레이기술학회지
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• 제13권1호
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• pp.43-49
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• 2014

Zinc-tin oxides (ZTO) thin film transistors have been fabricated at different process pressure via re sputtering technique. TFT properties were improved by depositing channel layers at lower pressure. From the analysis of TFTs comprised of multi layer channel, deposited consecutively at different sputtering pressure, it was suggested that the electrical characteristics of TFTs were mainly affected by interfacial layer due to their high conductance, however, the stability under the NBIS condition was influenced by whole bulk layer due to low concentration of positive charges, which might be generated by the oxygen vacancy transition, from Vo0 to $Vo^{2+}$. Those improvements were attributed to increasing sputtered target atoms and decreasing harmful effects of oxygen molecules by adopting low sputtering pressure condition.