• Proceedings of the Korean Ceranic Society Conference
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• 2000.04a
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• pp.71.1-71.1
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• 2000

• Carbon letters
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• v.16 no.2
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• pp.121-126
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• 2015

Carbon fibers are prepared by stabilizing pitch fibers accompanying electron beam (E-beam) irradiation. The carbon fibers pretreated by E-beam irradiation achieve a higher stabilization index than the carbon fibers that are only heat-stabilized. In addition, the carbon fibers subjected to E-beam irradiation in the stabilization step exhibit a comparable tensile strength to that of general purpose carbon fibers. The carbon fibers pretreated with an absorbed dose of 3000 kGy have a tensile strength of 0.54 GPa for a similar fiber diameter. Elemental, Fourier-transform infrared spectroscopy, and thermogravimetric analyses indicate that E-beam irradiation is an efficient oxidation and dehydrogenation treatment for pitch fibers by showing that the intensity of the aliphatic C-H stretching and aromatic $CH_2$ bending (out-of-plane) bands significantly decrease and carbonyl and carboxylic groups form.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.05a
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• pp.82-82
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• 1999

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.131-132
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• 2003

• 한국생태학회:학술대회논문집
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• 1998.05a
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• pp.80-80
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• 1998

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.413-419
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• 1997

The specimens which were prepared from cokes with additions of 0~25 wt% B4C were sintered in Ar atmosphere at 220$0^{\circ}C$. The effects of B4C content on graphitization and oxidation resistance of cokes were investigated. B4C accelerates the graphitization of cokes and at 220$0^{\circ}C$ the degree of graphitization increased from 0.33 which is the value of pure carbon to 0.56, which increased bluk density and porosity. Especially bending strength increased as th graphitization temperature increased. Oxidation resistance property was greatly improved when B4C was added more than 10wt% at 80$0^{\circ}C$ and when B4C was added more than 20wt% at 100$0^{\circ}C$. This was because that the thin layer of B2O3 glass phase on the surface of the composite could be identified to increase the oxidation resistance.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.159-159
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• 2009

In this work, nitrogen and oxygen functionalities was introduced to the graphite nanofibers (GNFs) and their effect on electrocatalytic performance of the GNF supports for direct methanol fuel cells (DMFCs) was invesigated. The nitrogen and oxygen groups were introduced through the urea treatments and acid treatment, respectively. And, PtRu catalysts deposited on modified GNFs were prepared by a chemical reduction method. The catalysts were characterized by means of elemental analysis, nitrogen adsorption, and X-ray photoelectron spetroscopy (XPS). The structure and morphological characteristics of the catalysts were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). As a result, the Pt-Ru nanoparticles were impregnated on GNFs with good formation in 3-5 nm. And, the cyclic voltammograms for methanol oxidation revealed that the methanol oxidation peak varied depending on changes of surface functional groups. It was thus considered that the PtRu deposition was related to the reduction of PtRu and surface characteristics of the carbon supports. The changes of surface functional groups were related to PtRu reduction, significantly affect the methanol oxidation activity of anode electrocatalysts in DMFCs.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.1
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• pp.57-66
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• 2001

Gas phase photocatalytic oxidation of tetrachloroethylene (PCE) under 370 nm ultra-violet irradiation was investigated with TiO$_2$ catalyst. During the photocatalytic oxidation of PCE vapor several kinds of intermediate were produced, and the reaction pathways were proposed on the basis of the production sequency of the intermediates. The intermediates in the pathways of PCE oxidation were hexachloroethane, pentachlotoethane, 1, 1, 2-trichloroethane, carbon tetrachl-oride, dichloroacetylchloride, chloroform, 1,1-dichloroethane, phosgene, CO, $CO_2$, HCl, Cl$_2$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.04a
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• pp.73-73
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• 2007

Amorphous BON and Si-DLC thin films were synthesized by the RF plasma enhanced CVD method, and their oxidation behavior was studied up to $500^{\circ}C$ in air. The oxidation of both films was accompanied by evaporation of volatile species. The oxidation of BON film was preceded by nitrogen escape from the film, and oxygen penetration into the film. The oxidation of Si-DLC film was preceded by carbon escape probably as CO or $CO_2$from the film, and oxygen penetration into the film. The inwardly transported oxygen simply stayed in the oxidized BON and Si-DLC thin films.

• Bulletin of the Korean Chemical Society
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• v.16 no.2
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• pp.183-186
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• 1995