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Volume 2001 (2001)
- Issue 200 Pages 202-
- Issue 199 Pages 155-
- Issue 198 Pages 125-
- Issue 197 Pages 83-
- Issue 196 Pages 1-
Volume 2001, Issue 197
Displaying 1-6 of 6 articles from this issue
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Juji Mondori, Chiharu Yamaguchi, Isao Mochida2001 Volume 2001 Issue 197 Pages 83-87
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe influences of stabilization extent were examined on the yield, strength and surface area of general purpose carbon and activated carbon fibers, respectively, prepared from isotropic air-blown coal tar pitch. The stabilization extent was described by the content of oxygen uptake after the stabilization. The amounts of oxygen uptake optimum for the high tensile strength, elongation, and surface area were found 10, 9 and 13wt%, respectively for the carbon and activated carbon fibers. Larger extent of stabilization reduced the yield of both fibers. The stabilization introduced oxygen into the pitch in forms of carbonyl, ketone, and phenol types of functional groups and accelerated the dehydrogenative condensation and aromatization as well. The volatilization also took place during the stabilization, becoming very marked above 350°C by evolving cracked gas. The cross-linkage can stabilize the pitch not to deform the fiber shape and maintain the axis-alignment of component aromatic planes induced at the spinning to give the strength of carbon fiber. An optimum oxygen uptake for the highest elongation may moderate cross-linkage to form linear chains of aromatic sheets leaving some flexibility among the chains.
In contrast, optimum oxygen uptake for the largest surface area by activation was higher than that for the highest strength. Sufficient three-dimensional cross-linkage may induce the voids among the aromatic planes during the carbonization and gas evolution which contribute to form large surface area by limited burn off.
Excess stabilization increases the number of oxygen functional groups, all of which leave as cracked gas at the carbonization, reducing the yield.
Thus the optimum stabilization extents must be carefully achieved for the best performances of resultant pitch based fiber materials.View full abstractDownload PDF (848K) -
Ryuji Ohshima, Hiroshi Yamanaka, Satoru Hosomi2001 Volume 2001 Issue 197 Pages 88-91
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSSuh-micron diamond powder was heat-treated and its machining pert ormance wax tested in the texturing process or fixed disk blanks. Comparison indicated a significant increase of up to some 30% in stock rein al. as well as a reduction of 5% in surlacc roughness over the corresponding diamond as untreated. Such improvement can be related to the et lect s of an incrased friability and thus in number or edges available I or the stock removal process. Scratch marks, on the other hand. were essentially eliminated as a result of the deposition of non-diamond carbon on the surfaces of diamond particles, so much as to leave only edge projection tips uncvoered.View full abstractDownload PDF (1940K) -
Hiroshi Shioyama, Arthorn Sanpanich, Mansor B. H. M. Saman2001 Volume 2001 Issue 197 Pages 92-95
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSIntercalation of EuCl3 and TbCl3 into graphite was carried out by contacting graphite with powder of EuCl3 or TbCl3 in the presence of chlorine. The observation of products by XRD showed that the extent of chlorides intercalation could be controlled through adjustment of the pressure of chlorine; increasing pressure tends to increase the extent of intercalation. In the case of EuCl3, the extent of intercalation varies to show a stage transition. On the other hand, TbCl3 intercalation gives a mixture of stage 2 graphite intercalation compound (GIC) and remaining graphite, where the extent of intercalation is revealed by the ratio of stage 2 GIC to graphite. The difference in the behaviour of intercalation could be attributed to the mobility of the chloride in the graphite interlayer.View full abstractDownload PDF (529K) -
[in Japanese]2001 Volume 2001 Issue 197 Pages 96-99
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (763K) -
Yoshikazu Nakayama2001 Volume 2001 Issue 197 Pages 100-107
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSThe development of a scanning probe microscope (SPM) has provided us with atomic resolution images even without a special condition of vacuum. Its principle is that a probe tip traces on the sample surface to detect the information. Thus the property of the tip is directly reflected on the SPM images. Since a carbon nanotube was discovered, it has attracted attention as an ideal material for a SPM tip because of its unique structure and shape. In this article, we will describe the development and subjects to be overcome of a microscope, the potential of a nanotube for a SPM tip, how we have applied a nanotube to a SPM tip, and what we have imaged and done using nanotube tips.View full abstractDownload PDF (10528K) -
[in Japanese], [in Japanese], [in Japanese]2001 Volume 2001 Issue 197 Pages 109-110
Published: May 15, 2001
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (332K)
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