• 한국안전학회지
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• 제9권4호
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• pp.69-76
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• 1994

Low density polyethylene is widely used as an insulating material In electric power cables. It is most important to know the beginning of its aging by partial discharge and UV-ray. That Is reason which we investigate chemiluminescence of the LDPE treated by partial discharge, UV-ray and corona discharge. We find that it takes one hour on spectra of IR but 0.17 minutes on chemiluminescence in the variation of chemical by partial discharge. Also we knew that Lithium carbonate-added(1phr) LDPE offered obvious suppressing effect on aging by partial discharge through the chemiluminescence. Therefore, the chemiluminescence is a highly sensitive and effective measurement method to appreciate characteristics of the treated surface and the oxidation reaction.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.89-92
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• 2007

Partail oxidation(POX) of n-butane was investigated in this research by employing ceria-promoted Ni/calcium hydroxyapatite catalysts ($Ce_xNi_{2.5}Ca_{10}(OH)_2(PO_4)_6$ ; x = $0.1{\sim}0.3$) which had recently been reported to exhibit good catalytic performance in POX of methane and propane. The experiments were carried out with changing ceria content, $O_2/n-C_4H_{10}$ ratio and temperature. As the $O_2/n-C_4H_{10}$ feed ratio increased up to 2.75, n-$C_4H_{10}$ conversion and $H_2$ yield increased and the selectivity of methane and other hydrocarbons decreased. But with $O_2/n-C_4H_{10}$ = 3.0, $n-C_4H_{10}$ conversion and $H_2$ yield decreased. This is considered due to that too much oxygen may inhibit the reduction of Ni or induce the oxidation of Ni, which results in poor catalytic activity. The optimum $O_2/n-C_4H_{10}$ ratio lay between 2.50 and 2.75. $Ce_{0.1}Ni_{2.5}Ca_{10}(OH)_2(PO_4)_6$ showed the highest $n-C_4H_{10}$ conversion and $H-2$ yield on the whole. In durability tests, higher hydrogen yield and better catalyst stability were obtained with the $O_2/n-C_4H_{10}$ ratio of 2.75 than with the ratio of 2.5.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.138-145
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• 2011

Diesel particulate filter (DPF) systems are being used to reduce the particulate matter emission of diesel vehicles. The DPF should be regenerated after certain driving hours or distance to eliminate soot in the filter. The most widely used method is active regeneration with oxygen at $550{\sim}650^{\circ}C$. Syngas (synthetic gas) can be used to lower the regeneration temperature of Catalyzed DPF (CDPF). The syngas is formed by fuel reforming process of CPOx (Catalytic Partial Oxidation) at specific engine condition (1500rpm, 2bar) using 1wt.% $Rh/CeO_2-ZrO_2$ catalyst. The oxidation characteristics of PM with syngas supplied to filter were studied using partial flow system that can control temperature and flow rate independently. The filter is coated with washcoat loading of $25g/ft^3$ $Pt/Al_2O_3-CeO_2$, and multi-channel CDPF (MC-CDPF) was used. The filter regeneration experiments were performed to investigate the effect of syngas exothermic reaction on soot oxidation in the filter. For this purpose, before oxidation experiment, PM was collected about 8g/L to the filter at engine condition of 1500rpm, bmep 8bar and flow temperature of $200^{\circ}C$ Various conditions of temperature and concentration of syngas were used for the tests. Regeneration of filter started at 2% $H_2$ and CO concentration respectively and inlet temperature of $260^{\circ}C$. Filter Regeneration occurs more actively as the syngas concentration becomes higher.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 춘계학술발표회 초록집
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• pp.5-5
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• 1999

A novel process is proposed to improve oxidation resistance of Ti-Al intermetallic compounds at elevated temperatures by both Cr addition and pre-sulfidation, where TiAl alloys withlor without Cr addition were sulfidized at 1173K for 86.4ks at a 1.3 Pa sulfur partial pressure in a $H_2-H_2S$ gas mixture. The pre-sulfidation treatment formed a thin Cr-Al alloy layer as well as 7~10 micrometer $TiAl_3$ and $TiAl_2$ layer, due to selective sulfidation of Ti. Oxidation resistance of the pre-sulfidation processed TiAl 4Cr alloy was examined under isothermal and heat cycle conditions between room temperature and 1173K in air. Changes in $TiAl_3$ into $TiAl_2$ and then TiAl phases as well as their effect on oxidation behavior were investigated and compared with the oxidation behavior of the TiAl-4Cr alloy as TiAl and pre-sulfidation processed TiAl aHoys. After oxidation for up to 2.7Ms a protective $Al_2O_3$ scale was formed, and the pre-formed $TiAl_3$ changed into $TiAl_2$ and the $Al_2Cr$ phase changed into a CrAlTi phase between the $Al_2O_3$ scale and $TiAl_2$ layer. The pre-sulfidation processed TiAl-4Cr alloy had very good oxidation resistance for longer times, up to 2.7 Ms, in contrast to those observed for the pre-sulfidation processed TiAl alloy where localized oxidation occurred after 81 Oks and both the TiAl and TiAl-4Cr alloys themselves corroded rapidly from the initial stage of oxidation

• 에너지공학
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• 제20권3호
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• pp.252-258
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• 2011

Nickel fiber mat was investigated as a potential structured catalyst for steam reforming of biogas in the temperature range of $600-700^{\circ}C$. The activity of as-received catalyst was very low owing to the smooth surface of fibers. Pretreatment of the catalyst by oxidation followed by reduction under methane partial oxidation condition significantly improved the catalytic activity, although degradation of the activity was found during the reaction due to oxidation and sintering. This deactivation was retarded by supplying additional hydrogen in the inlet gases or by coating $CeO_2$ over the catalyst surfaces.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.360-362
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• 1988

The new oxidation method was presented to grow the oxide layer by thermal reaction of $NH_{3}$ and $O_{2}$. The growth rate increased according as increase of partial pressure of $NH_{3}$. Optical transparent of the grown film was 12% compared with 17% of thermal oxidation when the wave number was $1,100cm^{-1}$. The oxide layer with good quaility was obtained.

• Bulletin of the Korean Chemical Society
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• 제9권2호
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• pp.81-84
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• 1988

The CO oxidation was performed on $H_2$-reduced NiO-${\alpha}-Fe_2O_3$ in the temperature range 150-$250^{\circ}C$. The kinetic study and the conductivity measurements indicate the oxidation reaction follows Langmuir-Rideal type process that is uncommon in heterogeneous catalyst$^1$. No active site is found on the catalyst surface for CO adsorption, but an oxygen vacancy adsorbs an oxygen, and this step is rate initiation. The partial orders are half for $O_2$ and first for CO, respectively. Apparent activation energy for over-all reaction is 9.05 kcal/mol.

• 한국재료학회지
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• 제20권4호
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• pp.217-222
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• 2010

Zirconium diboride (ZrB2) and mixed diboride of (Zr0.7Ta0.3)B2 containing 30 vol.% silicon carbide (SiC) composites were prepared by hot-pressing at $1800^{\circ}C$. XRD analysis identified the high crystalline metal diboride-SiC composites at $1800^{\circ}C$. The TaB2 addition to ZrB2-SiC showed a slight peak shift to a higher angle of 2-theta of ZrB2, which confirmed the presence of a homogeneous solid solution. Elastic modulus, hardness and fracture toughness were slightly increased by addition of TaB2. A volatility diagram was calculated to understand the oxidation behavior. Oxidation behavior was investigated at $1500^{\circ}C$ under ambient and low oxygen partial pressure (pO2~10-8 Pa). In an ambient environment, the TaB2 addition to the ZrB2-SiC improved the oxidation resistance over entire range of evaluated temperatures by formation of a less porous oxide layer beneath the surface SiO2. Exposure of metal boride-SiC at low pO2 resulted in active oxidation of SiC due to the high vapor pressure of SiO (g), and, as a result, it produced a porous surface layer. The depth variations of the oxidized layer were measured by SEM. In the ZrB2-SiC composite, the thickness of the reaction layer linearly increased as a function of time and showed active oxidation kinetics. The TaB2 addition to the ZrB2-SiC composite showed improved oxidation resistance with slight deviation from the linearity in depth variation.

• 한국전기화학회:학술대회논문집
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• 한국전기화학회 2002년도 연료전지심포지움 2002논문집
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• pp.111-116
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• 2002

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2008년도 추계학술대회 논문집
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• pp.430-431
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• 2008