• 한국표면공학회지
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• 제29권2호
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• pp.120-131
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• 1996

In order to improve the mechanical properties and the high temperature oxidation resistance, aluminizing was carried out at a temperature range between $850^{\circ}C$ and $1050^{\circ}C$. The pack cementation process was used to produce uniform layer. After each treatment, the microhardness and the characteristics of high temperature oxidation were tested to evaluate the properties of the aluminide layer. The aluminide layer consisted of FeAl above $1000^{\circ}C$, and $Fe_2Al_5$ below $900^{\circ}C$, and the mixed phase of FeAl and $Fe_2Al_5$ between 90$0^{\circ}C$ and $1000^{\circ}C$ in case of the mixture powder consisted of 5%Al+5%$NH_4Cl+90%AL_2O_3$. The microhardness of $Fe_2Al_5$ was obtained much as the twice as that of FeAl. As the aluminizing temperature and time increased, the thickness of aluminide increased. After aluminizing, the high temperature oxidation resistance was remarkably improved. The high temperature oxidation resistance of FeAl was superior to the resistance of high temperature oxidation of $Fe_2Al_5$.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.288-288
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• 2012

The oxidation characteristics of tungsten line pattern during the carbon-based mask layer removal process using oxygen plasmas and the reduction characteristics of the WOx layer formed on the tungsten line surface using hydrogen plasmas have been investigated for sub-50 nm patterning processes. The surface oxidation of tungsten line during the mask layer removal process could be minimized by using a low temperature ($300^{\circ}K$) plasma processing instead of a high temperature plasma processing for the removal of the carbon-based material. Using this technique, the thickness of WOx on the tungsten line could be decreased to 25% of WOx formed by the high temperature processing. The WOx layer could be also completely removed at the low temperature of $300^{\circ}K$ using a hydrogen plasma by supplying bias power to the tungsten substrate to provide an activation energy for the reduction. When this oxidation and reduction technique was applied to actual 40 nm-CD device processing, the complete removal of WOx formed on the sidewall of tungsten line could be observed.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.75-76
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• 2011

Hot-rolled steel plates of SPHC and SS400 were oxidized at 600, 750 and $900^{\circ}C$ for 2hr in air. With an increase in oxidation temperature, their oxidation rates increased, being accompanied with formation of pores and cracks in the thickened oxide scales that were non-adherent. The SPHC steels that were manufactured by either the arc furnace or the blast furnace displayed similar oxidation rates, indicating that their oxidation rates were insensitive to the manufacturing processes. The medium-carbon SS400 steel displayed a little faster oxidation rates than the low-carbon SS400 steel, indicating that the carbon content did not significantly influence the oxidation rates.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1149-1150
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• 2006

The oxidation of (W,Mo)$Si_2$ powders has been investigated at 400, 500 and $600^{\circ}C$ for 12.0 hours in air. It was shown that the low temperature oxidation resistance of (W,Mo)$Si_2$ was worse than that of $MoSi_2$, and they showed great changes in mass, volume and colour. Especialy at $500^{\circ}C$, the amount of volume expansion of (W,Mo)$Si_2$ was as high as about $7\sim8$ times and color changed from black to yellow after 4.0h with $MoO_3$, $WO_3$, (W,Mo)$O_3$ and amorphous $SiO_2$ as main reaction products. The mass gain and oxidation rate were relatively slower at $400^{\circ}C$ and $600^{\circ}C$ than that at $500^{\circ}C$.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 International Symposium on Magnetics The 2000 Fall Conference
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• pp.325-326
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• 2000

Low temperature diagnosis was performed as a probe for the integrity of MTJ(Magnetic tunnel junction) process which is optimised for the given plasma oxidation condition. TMR ratio increased slowly with decreasing temperature than that expected from spin wave exitation theory〔1〕. Junction resistance (RJ) does not follow T$\^$-$\frac{1}{2}$/ law below 200 K, indicating another conduction path besides spin polarized tunneling is involved at low temperature. Temperature dependence of conductance dip and bias dependence of TMR with temperature are discussed, from which the quality of tunnel barrier and its formation process can be inferred.

• 청정기술
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• 제19권4호
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• pp.469-475
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• 2013

본 연구에서는 팜 잔사유를 이용하여 고품위화된 저등급 석탄의 건조 안정화 특성을 알아보았다. 인도네시아 저등급 석탄인 에코탄을 사용하였고, 팜지방산증류물(palm fatty acid distillate, PFAD)을 혼합시킨 후 $107^{\circ}C$ 질소분위기에서 건조하였으며 그 후에 안정화 특성을 평가하였다. 교차점온도(crossing-point temperature, CPT) 측정을 통해 자연발화 경향을 확인하였으며, 저온산화 실험을 통해 $CO_2$, CO 가스 배출량은 건조석탄보다 고품위 석탄이 감소하는 것을 확인하였다. 수분 재흡착 실험을 통해 고품위 석탄이 대기방치와 항온항습 분위기에서 수분 재흡착이 줄어드는 것을 확인하였다. 고품위화된 석탄은 PFAD의 표면코팅을 통해 안정화 되며, 함량이 증가할수록 안정화도가 높아졌다.

• 한국대기환경학회지
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• 제14권4호
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• pp.313-320
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• 1998

The most desirable diesel oxidation catalyst (DOC) should have the properties of oxidibing CO and HC effectively at low exhaust gas temperature while minimizing the formation of sulfate at high exhaust gas temperature. Precious metals such as platinum and palladium have been known to be sufficiently active for oxidizing CO and HC and also to have high activity for the oxidation of sulfur dioxide (SO2) to sulfor trioxide (SO3). There is a need to develop a highly selective catalyst which can promote the oxidation of CO and HC efficiently, but, on the other hand, suppress the oxidation of SO2. One approach to solve this problem is to load a base metal such as vanadium in Pt-based catalyst to suppress sulfate formation. In this study, a Pt-V catalyst was prepared by impregnating platinum and vanadium onto a Ti-Si wash coated catalyst in a laboratory reactor by changing the formulations and reaction temperatures.

• Carbon letters
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• 제5권1호
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• pp.27-33
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• 2004

Structural changes of high modulus carbon fiber by oxidation in carbon dioxide gas using SEM, TEM, and XRD have been observed. It was shown that the originally high modulus carbon fiber is composed of highly ordered graphitic crystalline area and non-crystalline area. It was observed that the La increases during the whole oxidation process. It was shown that the oxidation of high modulus carbon fiber initiates at the non-crystalline area and at the ends of fiber. The large pores developed in fiber by direction of fiber length at high temperature ($1,100^{\circ}C$), and the small pores developed on the fiber surface at low temperature ($900^{\circ}C$). In conclusion, it is found that the oxidation of the carbon fiber was progressed through the imperfection.

• 한국물환경학회지
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• 제22권2호
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• pp.258-263
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• 2006

ANAMMOX (Anaerobic ammonium oxidation) reactor, which was cultivated ANAMMOX bacteria in mesophilic condition ($35^{\circ}C$), was operated to investigate the effects of temperature. In $20{\sim}30^{\circ}C$ of operation condition, which was assumed as field-temperature, total N removal and $NH_4-N$ removal rate were declined from about 2.50 and $1.27kg\;N/{m^3}_{reactor}-day$ (0.06 and 0.03 kg N/kgVSS/day) to 1.62 and $0.41kg\;N/{m^3}_{reactor}-day$ (0.04 and 0.01 kg N/kgVSS/day), In this range of temperature, ANAMMOX had very low activities but acid fermentation bacteria and denitrifiers, which were competitors of substrates, had high activities relatively. Though operation temperature was higher than inhibition condition for two months, ANAMMOX activities could not been recovered once they were inhibited by low temperature. This fact was resulted from very slow doubling time of ANAMMOX bacteria. This study shows that maintenance device of optimal temperature is necessary required in field application of ANAMMOX.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.742-754
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• 2020

Zircaloy cladding oxidation is an important phenomenon for both design basis accident and severe accidents, because it results in cladding embrittlement and rapid fuel temperature escalation. For this reason during the last decade, many experts have been conducting experiments to identify the oxidation phenomena that occur under design basis accidents and to develop mathematical analysis models. However, since the study of design extension conditions (DEC) is relatively insufficient, it is essential to develop and validate a physical and mathematical model simulating the oxidation of the cladding material at high temperatures. In this study, the QUENCH-05 and -06 experiments were utilized to develop the best-fitted oxidation model and to validate the SPACE code modified with it under the design extension condition. It is found out that the cladding temperature and oxidation thickness predicted by the Cathcart-Pawel oxidation model at low temperature (T < 1853 K) and Urbanic-Heidrick at high temperature (T > 1853 K) were in excellent agreement with the data of the QUENCH experiments. For 'LOCA without SI' (Safety Injection) accidents, which should be considered in design extension conditions, it has been performed the evaluation of the operator action time to prevent core melting for the APR1400 plant using the modified SPACE. For the 'LBLOCA without SI' and 'SBLOCA without SI' accidents, it has been performed that sensitivity analysis for the operator action time in terms of the number of SIT (Safety Injection Tank), the recovery number of the SIP (Safety Injection Pump), and the break sizes for the SBLOCA. Also, with the extended acceptance criteria, it has been evaluated the available operator action time margin and the power margin. It is confirmed that the power can be enabled to uprate about 12% through best-estimate calculations.