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991.
992.
Isao Mochida Keiko Kudo Noriyoshi Fukuda Kenjiro Takeshita Ryohei Takahashi 《Carbon》1975,13(2):135-139
Using aluminum chloride as a catalyst, polycyclic aromatic hydrocarbons were converted into carbons of two different structures, although at the early stage all carbonization processes proceeded via molten phase. The structures were examined with an optical microscope under crossed nicois. The first type of structure was a flow pattern with large oriented needle like domains observed for carbons obtained from naphthalene, chrysene, and anthracene, whereas the second one was a mosaic structure for carbon from pyrene. A significant subsequent graphitization at 2500°C (as expressed by Lc) took place for both types regardless of the different size of oriented domains. The orientation of domains depends on the rate of carbonization controlled by the holding temperature, time and quantity of the catalyst. Appropriate conditions of carbonization suppressing too fast generation of nuclei so as to permit the formation of ordered arrangement of condensed molecules were found to yield a needle-like coke also from pyrene, thus showing that the passing through a molten phase is not a sufficient condition for formation of a needle-like structure. 相似文献
993.
H Saito S Tsuchida H Fujita S Fukuda T Aisawa A Munakata Y Yoshida 《Canadian Metallurgical Quarterly》1982,79(10):1944-1949
994.
Shiba Koreyuki Handa Muneo Yamagishi Shigeru Fukuda Takeshi Takahashi Yoshihisa Tanifuji Takaaki Omori Shunzo Kondo Akinori 《Journal of Nuclear Materials》1973,48(3):253-263
In-pile release mechanisms of fission gas from UO2 at low temperatures were studied. The release of 133Xe, 135Xe, 138Xe, 85mKr, 88Kr and 87Kr from a sintered UO2 pellet was measured at temperatures ranging from 250 to 930°C using a graphite specimen holder. The release from the holder, in which a fraction of fission gas was recoil-implanted, was subtracted to obtain the net release from the UO2 pellet. Knock-out release from the UO2 was measured directly, and it was found that it was not the main release mechanism, at least not for short-lived nuclides. A ‘pseudo-recoil’ release model is proposed to explain the low temperature release under irradiation. In the model, some of the defects produced by fission fragments act as short-lived carriers for fission gas. 相似文献
995.
996.
This paper presents a probabilistic theory for predicting the strength of unidirectional short fibre composites. It is assumed that the failure of the composite occurs due to the inability of the short fibres bridging a critical zone to carry the load. The stress concentrations on the fibres bridging a fibre end gap are evaluated as a function of the number of fibre ends forming the gap. The sizes of the gaps are predicted from a probabilistic approach. The short fibre composite strength is then estimated from the gap size and the corresponding stress concentration factor. Comparisons of the present work with existing theories and experiments have been made.On leave from the Institute of Space and Aeronautical Science, University of Tokyo, Japan. 相似文献
997.
998.
Ultrathin (≃6 nm) oxynitrided SiO2 (SiOxNy) films have been formed on Si(100) by rapid thermal processing (RTP) in an N2O ambient. It is demonstrated that with this technology the generation of electron traps in bulk SiO2 and the low-field leakage during Fowler-Nordheim electron injection can be greatly reduced. This behavior of SiOx Ny film can be explained by the idea that the trap sites are reduced by forming strong Si-N bonds in bulk SiO2. This N2O oxynitridation is viewed as a hopeful technology for forming ultrathin EEPROM tunnel oxide films 相似文献
999.
Kurachi I. Fukuda Y. Miura N. Ichikawa F. 《Industry Applications, IEEE Transactions on》1994,30(2):358-364
The leakage increase of the off-state MOSFETs after an ESD event has been studied for output transistors with the thin gate oxide and LDD structures. Leakage increase called “soft breakdown” has been found at relatively low ESD testing voltages (200-300 V). This soft breakdown is caused by the creation of interface traps due to the snap-back stressing during the ESD event. The creation of interface traps has enhanced the interface trap to band tunneling current at the drain side of the MOSFETs. The improvement of the ESD threshold has also been proposed with an additional arsenic implantation into the n$ region. It has been confirmed that the arsenic implantation improved the HBM ESD threshold to more than 2000 V 相似文献
1000.