巻号一覧
1983 巻 (1983)
- 115 号 p. 155-
- 114 号 p. 97-
- 113 号 p. 47-
- 112 号 p. 2-
1983 巻, 113 号
選択された号の論文の5件中1～5を表示しています
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小川 一太郎, 吉田 久良, 小林 和夫1983 年 1983 巻 113 号 p. 47-52
発行日: 1983/04/20
公開日: 2010/06/28
ジャーナル フリーCharacteristics of the carbon solids made from ground raw-coke powder were investigated with increasing heat-treatment temperature.Byelectron microscopic observation it was known that microtexture of the ground raw-coke powder compact was consisted of spherical particles with 1-5μm size, which were fomed by agglomeration of small ground coke grains, and of some soluble component phases at the boundaries among particles.With increasing temperature the soluble component phases changed to porous texture and small pores less than 1μm size apPeared at the temperatures from 600°C to 1800°C.Coalescence of the particles occurred at 1500-1800°C and boundaries among Particles were not so clear any more as were observed below 1500°C Behaviors of the apPearances of the porous texture and the coalescence of particles Were considered to give some in fluences to the changes of strength and hardness of the carbon solids with heat-treatment temperature.
The carbon solid heat-treated at1300°C had the maximum bending strength of 700kg/cm2 and shore hardness of 120.Slight decrease of shore hardness, however, was observed at about 800°C which seemed to be predominantly due to the poreformation. Above 1300°C the strength and the hardness decreased with increasing temperature, and the carbon solid heat-treated at 2800°C showed bulk density of 1.959/cm3, bending strength of 500kg/cm2, shore hardness of 90, d (002) spacing of 3.38 Å and Lc (002) of about 200Å.抄録全体を表示PDF形式でダウンロード (7669K) -
大谷 杉郎, 小島 昭, 飯塚 重雄, 星野 新吾, 神津 正史1983 年 1983 巻 113 号 p. 53-59
発行日: 1983/04/20
公開日: 2010/06/28
ジャーナル フリーThe most appropriate conditions were determined for the preparations of carbon fiber reinforced carbon (CFRC) bar (2 mm in diameter) for the core materials of carbon dental implant, which require the flexural strength more than 150MN/m2, the compressive strength more than 100MN/m2 and th eelastic facture behavior.
The carbon fiber reinforced plastics were prepared by use of phenol resin containing some amounts of graphite powder and high performance carbon fiber (CF) heat-treatedp rior to forming, and then carbonized CFRCs up to1000°C under nitrogen.The most suitable composition of CFRC bar was fbund to be as follow;
2500°C treated CF: 65w/o
graphite powder: 15w/o
resin carbon: 20w/o
Then, the resulting unidirectionally CFRC bar (2 mm in diameter) was coated with low temperature pyrolytic carbon (LTPC, 0.5 mm in thickness) by use of cis-1, 2-dichloroethylene as a source.The LTPC coating resulted in agreat increase of compressive strength.Typical mechanical properties of the coated CFRC bar are 290MN/m2 in flexural strength, 9GN/m2 in flexural modulus and 145MN/m2 incompressive strength.
The brittle fracture behavior improved with raising the preheat-treatment temperature of CF and the CFRC bar reinforced with CF preheated at 2500°C exhibit fiber pull out more than 100μm in length at the fracture surface.While the bar coated with LTPC gave a trapezoid stres-strain curve and fiber pull out became shorter than that of theuncoated bar.抄録全体を表示PDF形式でダウンロード (6322K) -
M. Eto, K. Yamaguchi, Y. Sasaki, S. Enomoto1983 年 1983 巻 113 号 p. 60-65
発行日: 1983/04/20
公開日: 2010/06/28
ジャーナル フリーRadiotracer method by use of 85Kr was applied to non-stressed and prestressed nuclear graphites for the purpose of examining its effectiveness for detecting any microstructural difference among the graphites used in the study or any changes in pore and defect structures caused by prestressing.Materials used were three kinds of nuclear graphites, grades SM1-24, 7477PT and H327.After impregnation of specimens with 85Kr at 3.4×102 kPa, the counting rates for β-and γ-rays whichresulted from the residual 85Kr atoms were measured as a function of exposure time in air for the specimens prestressed to 0, 0.2 or 0.9 σm, where σm is the mean compressive strength.Three kinds of graphites behaved in different ways: In the case of SM1-24 graphite, the initial counting rates for β- and γ-rays increased with increasing prestress level, whereas the apparent half-life, which was defined as the time necessary for the counting rate to be a half of the initial rate, decreased as the prestress level increased.
For 7477PT graphite, prestressing to 0.2 σm made the initial rate smaller than that for the non-stressed.In the case of H327 graphite no strong influence of prestress was observed. From these results, it was concluded that the changes in pore and defect structures caused by prestress can be detected by the technique employed here at least for SM1-24 graphite.抄録全体を表示PDF形式でダウンロード (726K) -
本田 英昌1983 年 1983 巻 113 号 p. 66-78
発行日: 1983/04/20
公開日: 2010/06/28
ジャーナル フリーThe 1, 2, 3, 4 tetrahydroquinoline (THQ) has high solvency, high hydrogen donating capacity and high hydrogen shuttling capacity for coals and/or pitches.The THQ is used as a hydrogen donor solvent in the first stage process of coal liquefaction and/or of spinning pitch making for carbon fiber.
The advancement trends of the research and development in the solvolysis liquefaction of coal are reviewed.The solvolysis liquefaction process, that is the Honda and Yamada process, is a hybrid process containing the low-temperature thermal cracking of petroleum heavy residues and the liquefaction of coal by extractive chemical disintegration.For the more development of the solvolysis liquefaction, the importance of THQ is considered.As the first stage of coal liquefaction, the short contact time solvolysis and qualifying (SCT-SQ) process with THQ is proposed.And also the two stage liquefaction of coal, that is SCT-SQ as the first stage process, and the lightening and/or upgrading as the second stage process, is proposed.
In order to get the high performance pitch-based carbon fiber, it is necessary to control the transverse texture of pitch fiber by the pretreatment of raw pitch, the constitution and the spinability of spinning pitch, the spinning conditions and so on.It is obvious that the preordered larger transformation, the improvement of spinability and the thermal stability are required in the spinning pitch.For the pretreatment and/or modification such as hydrogenation and degradation of raw pitch, the importance of THQ is considered in the first stage of spinning pitch making.As the second stage of spinning pitch making, the separation of useless components and the controlled polycondensation of the isophase pitch made from raw pitch by the THQ treatment are necessary.
It is supposed that, although the polymerization degree may have some differences, the chemical structure and chemical constitution are similar to that in the products from coal and/or pitch, because the reaction mechanism is considered analogous in the first stage process of coal and/or pitch with THQ treatment.The difference in the coal liquefaction and the spinning pitch making occurs in the second stage process, since the former is in need of a controlled progressive reaction and the latter is in need of a controlled retrogressive reaction.抄録全体を表示PDF形式でダウンロード (1656K) -
大谷 杉郎, 大谷 朝男1983 年 1983 巻 113 号 p. 79-88
発行日: 1983/04/20
公開日: 2010/06/28
ジャーナル フリーPDF形式でダウンロード (1303K)
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