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Volume 1996 (1996)
- Issue 175 Pages 243-
- Issue 174 Pages 195-
- Issue 173 Pages 137-
- Issue 172 Pages 71-
- Issue 171 Pages 2-
Volume 1996, Issue 173
Displaying 1-9 of 9 articles from this issue
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Ikuo Abe, Mitsunori Hitomi, Nobuo Ikuta, Hideki Tatsumoto, Yoshiya Ker ...1996 Volume 1996 Issue 173 Pages 137-141
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMicroporous carbons were produced by an activation using air from Japanese cypress charcoal. Effects of activation time, activation temperature, and air flow rate on the yield, porosity, and adsorption property of the microporous carbons were examined and the following results were obtained.
(1) The weight loss increases linearly with activation time.
(2) The formation efficiency of pore which has an adsorption ability increases with activationtemperature.
(3) When the weight loss is above 95 %, the adsorption ability decreases.
(4) The activation efficiency increases with decreasing air flow rate.
(5) As activation temperature and air flow rate are constant, the specific surface area and mean pore diameter increase with activation time.
(6) As the specific surface area is constant, the mean pore diameter decreases with increasingactivation temperature.
(7) The mean pore diameter increases with weight loss.View full abstractDownload PDF (548K) -
Kyoichi Oshida, Naotaka Ekinaga, Morinobu Endo, Michio Inagaki1996 Volume 1996 Issue 173 Pages 142-147
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSParameters of strength of isotropic high-density graphite are thought to be strongly correlated to pore structure of the graphite from experimental results on fracture toughness. Until now the pore structure has not been analyzed quantitatively, and the relation between the parameters of strength and the pore structure has not been explained clearly. In the present paper, pore structure of the isotropic graphite has been analyzed by means of a polarizing microscope combined with an image analyzer. The polarizing microscope images of the isotropic graphite are digitized using an image scanner. Distribution of area size, number, circularity, and fractal dimension of cross-section of the pores are measured, and are analyzed quantitatively. When there is an increase in the number of small pores, the elastic modulus and bending strength also increase. We believe that a structure which includes many pores increases plane strain fracture toughness (KIC) and critical crack opening displacement (CODf), because crack propagation can be inhibited by the pores.View full abstractDownload PDF (1199K) -
Takao Yoshikawa, Akira Kojima, Sugio Otani, Eiichi Yasuda1996 Volume 1996 Issue 173 Pages 148-153
Published: July 30, 1996
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSIn the paper, we prepared the carbon fibers/epoxy resin composites using modified carbon fibers by a new surface modification method named photo-oxygenation. Effects of the surface modification of carbon fibers on the properties of the composites and matrix resin have been studied through the estimation of color and dynamic viscoelastic properties of the composites. The obtained results are as follows.
(1) Color and the dynamic viscoelastic properties of the composites change with carbon fibers' surface modified or not. So it is seen that the surface modification of reinforcing fibers changes not only the interphase but also the structure of matrix resin and its curing behavior.
(2) The color properties and crosslinking density of the matrix resin are linearly related, so the color properties will be able to be applied for the quality control as curing estimation.View full abstractDownload PDF (761K) -
Takao Yoshikawa, Saburo Endo, Akira Kojima, Sugio Otani, Eiichi Yasuda1996 Volume 1996 Issue 173 Pages 154-160
Published: July 30, 1996
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSChanges in the curing properties of matrix epoxy resin and the dynamic viscoelastic properties of the composites have been studied for the purpose of research on the properties-change mechanism of composites depending on the surface modifed reinforcing fibers. The dynamic viscoelastic properties of the composites using the surface modified carbon fibers by photo-oxygenation were measured by torsional braid analysis (TBA). The curing properties using epoxy resin added with model reactants involving carboxyl or hydroxyl group were measured by differential scanning calorimetry (DSC) analysis. The obtained results are as follows.
(1) The dynamic viscoelastic properties in curing of epoxy resin on carbon fibers were changed by photo-oxygenation. The Gr-onset temperatures, the gelation temperatures and the activation energies induced from TBA data were down. The glass transition temperatures after cure were up.These show that easy to react and well-progressed changes were induced by using the surface modified cabon fibers.(2) The hydroxyl group was superior to the carboxyl group in the promoting effect of epoxy curing reaction.View full abstractDownload PDF (821K) -
Shinji Sato, Akira Kohyama, Sachio Seto1996 Volume 1996 Issue 173 Pages 161-167
Published: July 30, 1996
Released on J-STAGE: July 05, 2011
JOURNAL FREE ACCESSThe compressive fracture processes in flat woven carbon fabrics reinforced carbon composite materials (C/C composites) were studied “in-situ” by means of optical microscopy. The compressive fracture strength obtained was 110MPa and 90MPa for the C/C composites with the final heat treatment at 1873K and 3273K, respectively. For the former composite, the specimen size dependence of fracture strength was seen with the specimen length smaller than 25mm, where the fracture strength was increased with decreasing the specimen length. The initial crack formation between fiber bundles crossed each other was observed at a quarter of the fracture stress. At about 95 % of the fracture stress, inter-laminar de-bonding was observed. The second cracking stage was very fast, followed by catastrophic fracture. For the latter composite, the catastrophic fracture was followed immediately after the first crack initiation. These fracture characteristics were interpreted mainly in terms of the difference in graphitization at interfaces caused by the final heat treatment.View full abstractDownload PDF (1731K) -
Masaharu Takehara, Yoshinori Matsumoto, Toshiki Kingetsu, Hiroki Masum ...1996 Volume 1996 Issue 173 Pages 168-171
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSInterlaminar shear strength (ILSS) measurements were performed on two kinds of C/C composites (sample A and B) to study the effect of fiber orientation on the shear strength. Sample A (C/C-501, Ohwada Carbon Co.) is reinforced with plain-woven cloths (2D-C/C), and sample B (BN-M, Nippon Steel Chemical Co.) is reinforced with random chopped fibers. ILSS was measured at elevated temperatures by a double notched compression method. Sample A was found to be one half of sample B in value of ILSS at room temperature. The ILSS of both types of composites increased with increasing measurement temperature. The typical fractured surfaces of sample A tested at room temperature showed flat planes and the shear failure was caused by the delamination between CF cloths and matrices. As for sample B, the boundaries of the fiber preforms were not observed clearly, and the shear failure seemed to initiate not from the special portions but from the randomly distributed microcracks within the preforms. At high temperatures, the fractured surfaces of all samples were found to be rough. The results suggest that the values of ILSS measured at high temperatures became higher than those measured at room temperature because of release of the internal residual stress and closure of preexisting cracks.View full abstractDownload PDF (893K) -
Takeo Ohte, Yori Izumi, Masaaki Katoh, Sugio Ohtani, Akira Kojima1996 Volume 1996 Issue 173 Pages 172-185
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSMethods of generation, diagnosis, control and application to carbon materials on cold plasmas are related from the standpoint of techniques for adding useful functions to carbon surfaces by the plasmas. Cold plasma has been used in many fields, such as semiconductor fabrication, diamond synthesis and surface improvement of various materials. In case of using cold plasmas, it is necessary to know their merits and demerits on the application. Also, methods of their generation, diagnosis and control are important. Becase the cold plasmas are generated mainly by discharges, such as corona discharge, glow discharge and arc discharge, these plasma generation methods are stated. With respect to diagnosis methods, the single probe method and the double probe method, which are used frequently for the application of the plasmas, are described in detail. Plasma control is one of the most important techniques for the surface modification. Sheath voltage control is a method for energy control of the incident ions onto the material surface, which influences the characteritics of the surface. Several methods for it are shown in this paper. By using these methods of generation, diagnosis and control of plasma, useful functions could be given to carbon surfaces. These techniques are related. The accurate, damage-less and wide-range control of wettability on carbon surface without temporal change became possible. A basic study for modifying the three-dimensinal materials was carried out. Damage-less etching was made without decreasing etching rate. Surface modification by using plasmas has posibilities on adding various more excellent functions to carbon material surfacesView full abstractDownload PDF (3371K) -
[in Japanese]1996 Volume 1996 Issue 173 Pages 186
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (1262K) -
[in Japanese]1996 Volume 1996 Issue 173 Pages 188
Published: July 30, 1996
Released on J-STAGE: June 28, 2010
JOURNAL FREE ACCESSDownload PDF (156K)
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