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Volume 1997 (1997)
- Issue 180 Pages 217-
- Issue 179 Pages 145-
- Issue 178 Pages 101-
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Volume 1997, Issue 180
Displaying 1-12 of 12 articles from this issue
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Ichiro Ueno, Hidetoshi Morotomi1997 Volume 1997 Issue 180 Pages 217-221
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCarbonization behavior of pitch/phenolic resin mixtures, especially the interaction between them, was investigated. Three types of pitch, coal tar pitch (CTP), hydrogenated coal tar pitch (H-CTP) and petroleum pich (PP) were used. Carbon yields of pitch/phenolic resin mixtureswere lower than the additivity line for all mixtures and the size of optical texture in coke was minimized when the carbonization yields was minimum value. It was evident that the change of chemical structure of mixtures at the initial stage of carbonization were effected by the hydrogen donor abilities of pitches. In the case of CTP, which have less ability of hydrogen donor than H-CTP, molecular weight of CTP/PR increased and large amount of phenoxyl group was remained even after heat-treatment. On the other hand, no difference of molecular weight and less phenoxyl group were observed for H-CTP. A model of the carbonization mechanism for pitch/phenolic resin mixture was proposed. The fineness of optical texture is considered to be due to the formation of cross-linking structures which is formed by phenoxyl radicals from phenolic resin, at the initial stage of carbonization. But in the case of H-CTP which has high hydrogen donor ability, phenol group in the phenolic resin is decomposed by the attack of hydrogen liberated from H-CTP, disturbing to form cross-linking structures and consequently resulting in large size of optical texture of coke.View full abstractDownload PDF (2317K) -
H. Hatori, Y. Yamada, Y. Nagata, M. Shiraishi1997 Volume 1997 Issue 180 Pages 222-228
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCarbonization and graphitization of two types of polyimide particles, with high crystallinity and in amorphous state, were investigated. A highly crystalline particle with the size of a few micrometers is an aggregate of plates, and amorphous one has a spherical shape with the diameter under 1μm. Change in X-ray diffraction profile by heattreatment around 500°C was small, indicating the packing structure of polyimide molecules in each particle is maintained up to the pyrolysis temperatures. No difference, however, was observed in carbonization behaviors analyzed by TGGC. The amorphous particle treated at 2800°C has a microtexture of non-graphitized carbon in which the layered structure isotropically winds in a short range. On the other hand, the microtexture of carbon prepared from the crystalline one is anisotropic, that is, the graphite-like ribbons are considered to have a spiral or compressed-spiral configuration in a rod-like unit constructing the particle.View full abstractDownload PDF (6989K) -
N. Hasegawa, Y. Gamo, M. Terai, M. Okuzawa, C. Oshima, S. Otani1997 Volume 1997 Issue 180 Pages 229-234
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSBy chemical vapor deposition, we have grown monolayer epitaxial films of graphite nano-crystals and graphite nano-ribbons on TiC (111)-facet surface and TiC (410) surface, respectively. Some properties of these graphite monolayer films have been studied by X-ray photoelectron spectroscopy (XPS), low energy electron diffraction (LEED) and angle-resolved ultraviolet photoelectron spectroscopy (ARUPS). The graphite nano-films have been successfully prepared by ethylene exposure of 6×105 L on the TiC (111)-facet surface at 1250°C, and the nano-ribbons by 2×104 L on the TiC (410) surface at-1050°C.View full abstractDownload PDF (4685K) -
Y. Ohashi, T. Koizumi, T. Yoshikawa, T. Hironaka, K. Shiiki1997 Volume 1997 Issue 180 Pages 235-238
Published: December 30, 1997
Released on J-STAGE: March 01, 2011
JOURNAL FREE ACCESSIn order to investigate the effect of film thickness of thin graphite crystals on the electrical properties, we prepared thin graphite films by cleaving a kish graphite (KG) crystal with the rrr value of 32.3. The values of the thickness of the graphite films were ranging from around 300 to 1000Å. Keeping these graphite films free from strain, we measured the temperature dependence of the in-plane resistivity between liquid helium and room temperatures. The experimental results could be expressed by a simple two band model and the Sugihara's theory for lattice vibration in thin-carbon films. By using these expressions, we estimated the overlap energy E0 of conduction and valence bands for the thin graphite films with various thicknesses. It was found that E0 decreases with decreasing film thickness. We also estimated the reciprocal of the relaxation time due to lattice defects or surface scattering l/τi and that due to lattice vibration l/τi for the thin films with various thicknesses. Consequently, it was found that the effect of l/τi increases rapidly, as the film thickness decreases. KEYWORDS graphite, thin film, resistivity, size effect, band overlap energyView full abstractDownload PDF (575K) -
Yasuo Mizutani, Takeshi Abe, Eiji Ihara, Kazuhiro Ikeda, Minoru Inaba, ...1997 Volume 1997 Issue 180 Pages 239-244
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIntercalation of alkali metals (Li, Na, K, Rb and Cs) into natural graphite flakesby the solvent method usingtetrahydrofuran (THF), 2-methyltetrahydrofuran (MeTHF) and 2, 5-dimethyltetrahydrofuran (diMeTHF) has beenstudied by X-ray diffractometry (XRD). Using THF as a solvent, ternary graphite intercalation compounds (GICs) withalkali metalsand the solvent are formed for all alkali metals. In the case of Li, however, situation is different; XRDpatterns of binary Li-GICs, which were observed in the early stage of thepreparation of Li-THF-GIC, disappeared asthe reaction time increased. In the Rb-THF solution, three types of ternary GICs with different Ic are formed by varyingthe preparation temperature. When MeTHF is used as a solvent, binary GICs are obtained for Li, Na and K, and bothbinary and ternary GICs are formed for Rb and Cs. In the case of diMeTHF solvent, only binary GICs are formed for all kinds of alkali metals except Na.View full abstractDownload PDF (1128K) -
Kayoko Morishita, Takayuki Takarada, Kunio Uchida, Motoo Yumura1997 Volume 1997 Issue 180 Pages 245-249
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe purification of carbon nanotube using gasification reaction was investigated. Carbon nanotube-containing material was gasified with oxygen, carbon dioxide and hydrogen using a thermo-balance, and etched with hydrogen plasma and oxygen plasma. The gasification behavior of carbon nanotube-containing materials strongly depended on the gasification agent and carbon nanotube was able to be purified with oxygen, carbon dioxide and hydrogen plasma. Under the experimental conditions examined the gasification with oxygen at a temperature of 750°C was most efficient to purify carbon nanotube.View full abstractDownload PDF (5146K) -
M. Kawaguchi, K. Hatani, Y. Wakukawa, K. Tatsumi, H. Shioyama1997 Volume 1997 Issue 180 Pages 250-252
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSLewis acid-base type adducts (CH2CHCN) 2: BCl3 and CH2CHCN: BF3 have been prepared and converted by pyrolysis into graphite-like materials of approximate compositions BC6N2H3 and BC21N2H3, respectively. 13C-NMR study suggests existence of two kinds of acrylonitrile molecules in the adduct (CH2CHCN) 2: BCl3 and three kinds of carbon atoms in the layer of BC6N2H3.View full abstractDownload PDF (449K) -
Kuniaki Tatsumi, Shun-ichi Higuchi, Hiroshi Ishikawa1997 Volume 1997 Issue 180 Pages 253-256
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSCrystallographic and electrochemical characteristics of a carbon as a by-product of a SiC production in an Acheson-style furnace were examined as an anode material of rechargeable lithium-ion batteries. The X-ray diffraction pattern of the carbon indicates that the carbon is highly graphitized. The fine powder (9.4μm in average) of the carbon gave a reversible capacity of ca. 370 mAh g-1 between the cut-off voltages, 0 and 2.5V (vs. Li/Li+), in 1 mol dm-3-LiClO4/ethylene carbonate + diethylcarbonate (50: 50 mixture in volume) electrolyte. Moreover, the potential change of the carbon during the electrochemical intercalation and deintercalation of lithium was almost the same as that of natural graphite showing slopes and plateaus. These results indicate that the carbon is an artificial graphite as well graphitized as natural graphite.View full abstractDownload PDF (2506K) -
Mitsutaka Fujita1997 Volume 1997 Issue 180 Pages 257-265
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe dimensionality effect of carbon materials is discussed relating to the topological extension of graphite sp2 network and the resultant π electronic structure. Introducing the polygonal defects into a graphite network, we can construct from zero-dimensional fullerene molecules to three-dimensional spongy structures. If you mince graphite, the dimensionality diminishes easily from two to zero. Based on these dimensionality-controlling schemes, we discuss how the It electronic state changes reflecting the topology and dimensionality of carbon atomic network.View full abstractDownload PDF (1765K) -
Takashi Kyotani, Akira Tomita1997 Volume 1997 Issue 180 Pages 266-272
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSA template carbonization technique was developed for synthesizing novel carbon materials. This technique utilizes the inorganic substances whose openings or pores are controlled at nanometer level. The first attempt was to prepare thin graphite films by the carbonization of organic polymer in the two-dimensional opening between the lamellae of a layered clay. Then, this technique was applied to the preparation of one-dimensional carbon such as carbon tubes by using an anodic aluminum oxide film as one-dimensional template, and uniform hollow nanotubes with open ends were obtained. Furthermore, a well-defined nano space in zeolite was utilized for the synthesis of novel porous carbon materials. The present review introduces the one- and three-dimensional approaches using the anodic oxide film and zeolite as a template and describes the structure of the resultant carbon materials prepared from these template techniques.View full abstractDownload PDF (11356K) -
[in Japanese]1997 Volume 1997 Issue 180 Pages 273
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1336K) -
[in Japanese]1997 Volume 1997 Issue 180 Pages 276
Published: December 30, 1997
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1720K)
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