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81.
Kazuhide Kemmochi Masayoshi Seike Kazunori Sato Akira Yanase Hiroshi Katayama-Yoshida 《Journal of Superconductivity and Novel Magnetism》2005,18(1):37-40
We propose new-type ferromagnetic semiconductors based on CaO and K2S without any transition metal elements. These materials show transparent and half-metallic ferromagnetism if the deep-impurity-band width (W) induced by doping of C, N, Si, or Ge impurities, and the electron-correlation energy (U) satisfy the Stoner’s condition of highly correlated electron system (U>W). Based on our first-principles calculations, we demonstrate that these materials satisfy the Stoner’s condition, and could be new candidates for transparent and half-metallic DMSs. 相似文献
82.
Masaki Tsuji Seiji Isoda Masayoshi Ohara Akiyoshi Kawaguchi Ken-ichi Katayama 《Polymer》1982,23(11):1568-1574
Individual chains comprising a β-form poly(p-xylylene) (PPX) single crystal were resolved with a high resolution electron microscope (JEM-500). In a polymer crystal the important limiting factor for resolution is radiation damage. The total end point dose of a PPX crystal is about 0.5 coulomb cm?2 for 500 kV electron irradiation which is more than 20 times greater than that for a polyethylene crystal. The high resolution image obtained was processed by optical filtering to reduce noise due to the granularity of film. The processed image, which corresponds to the ab-plane projection of polymer chains, shows clearly the mutual arrangement of each molecule in the crystal. This high resolution image is sufficient to provide a starting point for determining the unknown crystal structure of the β-modification of PPX. 相似文献
83.
Jin-ichi Nakamura Yoichi Takahashi Shin-ichiro Izumi Masayoshi Kanno 《Journal of Nuclear Materials》1980,88(1):64-72
The heat capacities of metallic uranium and thorium from 80 to 1000 K have been determined by laser-flash calorimetry. The results on uranium agree very well with those in the literature over the temperature range investigated. The results on thorium are several percent lower than the heat-capacity values hitherto reported, while the enthalpy data at high temperatures in the literature are in good agreement with the present results. Shomate's analysis showed that the present results are the most consistent through the temperature range from 80 to 1000 K. On this, a revised table of thermodynamic functions of thorium from 80 to 1000 K is presented. The excess heat capacity on thorium has been found to be not appreciable up to 1000 K, in contrast with the large excess heat capacity above 300 K for uranium. 相似文献
84.
A multiphase dc‐dc converter is effective for miniaturization and achieving high‐power density in a switching power supply. However, its mathematical modeling becomes complex as the phase number of the circuit increases. This study proposes a new modeling method to derive a reduced‐order method in a simple manner. The frequency characteristics of the reduced‐order model are fit to those of the original mathematical model of the multiphase dc‐dc converter. Therefore, the efficacy of the proposed method is validated. 相似文献
85.
Catalysis Letters - Presently, combining MoP as a co-catalyst and another subjective semiconductor into a composite catalyst often requires the use of various complex reduction methods. In this... 相似文献
86.
Bo Peng Chika Takai Hadi Razavi-Khosroshahi M S EL Salmawy Masayoshi Fuji 《Advanced Powder Technology》2018,29(8):1865-1870
Carbon composite ceramics have much attention for industry because of their excellent properties such as strong toughness, high electrical conductivity as well as low percolation threshold. Therefore, carbon nanotubes (CNTs) were used to incorporate with silica ceramics in order to improve their electromagnetic properties. The amount of CNTs in CNTs/silica composite ceramics was varied in order to investigate its effect on morphologies and electromagnetic properties of those. The composites were successfully fabricated by non-firing process. The results revealed that the obtained CNTs/silica composite ceramic have an electrical resistivity of 66.6?Ω·cm with a bending strength of 13.8?MPa. At the same time, the electromagnetic wave absorption ability achieved 70% over a wild frequency. This indicates that the CNTs in CNTs/silica composite ceramics may be potentially applied for an electromagnetic wave reflective material. 相似文献
87.
Bo Peng Chika Takai Hadi Razavi-khosroshahi Masayoshi Fuji 《Advanced Powder Technology》2018,29(9):2091-2096
Carbon nanotube/ceramic composites have been in the spotlight thanks to their excellent properties. Sintering is the vital part of ceramics fabrication in terms of reliability, however sintering the carbon nanotube (CNT) based ceramic composites is a challenging task. In this study, interfacial bonding of silane functionalized CNT with silica ceramic is investigated by a non-firing sintering process. CNTs are first treated by a mixed acid with the aid of a silane 3-aminopropyl triethoxysilane (APTES), which improves the chemical bonding and dispersibility of CNT in ceramic bodies. The extent of APTES chemical functionalization and mechanical property of CNT/silica ceramic composites are characterized using Raman spectrometer, FT-IR analysis, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and three-point bending strength measurement. Results show that composites are successfully prepared without sintering with stable CNT-silica interface, superior dispersibility, and good mechanical properties. 相似文献
88.
Chika Takai-Yamashita Hidenori Nagamine Yuki Nakashima Peng Bo Masayoshi Fuji 《Advanced Powder Technology》2018,29(12):3062-3069
We developed a simple and versatile technique for a particle’s self-organizing-network based on a non-solvent induced micro-phase separation (NIPS). When a good solvent vaporizes from a particle dispersion in a ternary solution including the polymer, good solvent and non-solvent, the suspension is separated into the polymer network and non-solvent phase. If the affinity between the particles and polymer is sufficient enough, the particles are entrapped in the polymer network and particle network can be achieved. To expand this technique to particles with various physical properties, the surface of the particles was identified using the Hansen dispersibility parameter (HDP). From a comparison of the HDP of the unmodified and modified silica, an NH2 group is suitable for entrapment of the silica by cellulose acetate as the polymer. However, with an increase in number of the silica particles, entrapment of the silica in the polymer was prevented. Control of the phase separation rate by the lowering temperature leaded to entrapment of silica particles in the polymer network. The proposed technique is effective not only for spherical oxide particles, but also for non-oxides, various shapes and structures. Depending on particle characteristics, functional films and bulk materials for thermal insulation, light diffusion, and electro conductivity can be obtained. 相似文献
89.
Yukiya Yamashita Kei Ishiguro Daisuke Nakai Masayoshi Fuji 《Advanced Powder Technology》2019,30(5):1051-1057
The effect of external additives on the synthesis of fumed TiO2 with a high rutile structure content was studied. The focus of this investigation was on the external additive species, agglomerates of the fumed TiO2 before and after the thermal treatment. The transformation ratio from the anatase to rutile structure of the thermally-treated fumed TiO2 was investigated as a function of the fumed TiO2 agglomerate before the thermal treatment. Small agglomerated powders resulted in a decrease of transformation temperature. Two novel results were obtained in this investigation. One was a new fumed TiO2 with a 100% rutile structure having an excellent dispersibility being successfully synthesized by the thermal treatment of AEROXIDE® TiO2 P 25 with a small portion of AEROSIL® R 972. The other was the remarkable acceleration of the transformation from the anatase to rutile structure and grain growth/sintering of the thermally-treated fumed TiO2 observed at a relatively low thermal treatment temperature by the oxidation reaction of calcium stearate as an external additive. 相似文献
90.
Masayoshi Okubo Akira Yamada Susumu Shibao Katsuhiko Nakamae Tsunetaka Matsumoto 《应用聚合物科学杂志》1981,26(5):1675-1679
Emulsifier-free emulsion polymerization of styrene in acetone–water medium was carried out using potassium persulfate as initiator. Below acetone content of 40 vol %, stable emulsion was prepared and polymerizations were remarkably fast compared with those in pure water. The particle size decreased from 0.5 to 0.17 μm with an increase in acetone content in the range 0–40 vol %, and the distributions were very sharp. The optimum polymerization for the preparation of the stable emulsion was: styrene, 20 vol %; acetone/water, 40/60 (v/v); KPS, 3.4 × 10?3 mole/l; temp., 90°C. 相似文献