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101.
Michio Takeda Akinori Saeki Jun-ichi Sakamoto Yoshikazu Imai Hiroshi Ichikawa 《Journal of the American Ceramic Society》2000,83(5):1063-1069
SiC-based fibers with various chemical compositions were synthesized using an irradiation-curing process. Polycarbosilane (PCS) fibers were cured by irradiation with an electron beam in a helium atmosphere. The cured PCS fibers were pyrolyzed at 1300°C under controlled hydrogen or argon atmospheres, and SiC fibers with C/Si of 0.84 to 1.56 were obtained. The fibers consisted of <1.0 wt% O, <0.2 wt% N, <0.1 wt% H, with the balance being Si and C. The mechanism of pyrolytic transformation of cured PCS to SiC-based ceramics was investigated using TG/DTA analysis. Greater mass losses were observed during pyrolysis in a hydrogen atmosphere than in argon. This result suggests that the hydrogen atmosphere suppresses H2 evolution and helps to remove excess carbon as CH4 during pyrolysis. The microstructure and mechanical properties of the resulting SiC-based fibers were found to be very dependent on their C/Si chemical compositions. 相似文献
102.
Toshihiro Isobe Takuya Umezome Yoshikazu Kameshima Akira Nakajima Kiyoshi Okada 《Materials Research Bulletin》2009,44(11):2045-3464
Using solid-state reaction method, Zr2WP2O12 powder was synthesized for this study. The optimum heating condition was 1200 °C for 4 h. The obtained powder was compacted and sintered. The relative density of the Zr2WP2O12 ceramics with no sintering additive was 60%. That of samples sintered with more than 0.5 mass% MgO was about 97%. The average grain size (D50), as estimated from the polished surface of a sample sintered at 1200 °C for 4 h was about 1 μm. The obtained ceramics showed a negative thermal expansion coefficient of about −3.4 × 10−6 °C−1. Young's modulus, Poisson's ratio, three-point bending strength, Vickers microhardness, and fracture toughness of the obtained ceramics were, respectively, 74 GPa, 0.25, 113 ± 13 MPa, 4.4 GPa and 2.3 MPa m1/2. 相似文献
103.
Hiroki Takahashi Takahiro Tomita Hiroyuki Takahashi Yoshikazu Mizuguchi Yoshihiko Takano Satoshi Nakano Kazuyuki Matsubayashi Yoshiya Uwatoko 《Science and Technology of Advanced Materials》2012,13(5)
The superconducting transition temperature, Tc, in iron-based solids can be enhanced by applied pressure: Tc increases from 8 to 37 K for the 11-type FeSe when the pressure is raised from 0 to 4 GPa. High-pressure studies can elucidate the mechanism of superconductivity in such novel materials. In this paper, we present a high-pressure study of Fe(Se1−xTex) and Fe(Se1−xSx). In the case of Fe(Se1−xTex), the maximum Tc under high pressure did not exceed the Tc of FeSe, which can be attributed to the structural transition to the monoclinic phase. For Fe(Se1−xSx) (0 < x < 0.3), Tc exhibited a significant increase with pressure; however, the maximum Tc under high pressure did not exceed the Tc of FeSe. This may be due to the disorder induced by substituting S for Se, which is similar to the pressure effect on Tc for the 1111-type superconductor Ca(Fe1−xCox)AsF. The Tc of Fe(Se1−xSx) showed a complex behavior below 1 GPa, first decreasing and then increasing with increasing pressure. From high-pressure x-ray diffraction measurements, the Tc (P) curve was correlated with the local structural parameter. 相似文献
104.
Artificial retina chips which can simultaneously sense and process real world images are described. The comparison between
artificial retinal systems and conventional image processing systems is described. Variable sensitivity photodetection, which
is an essential technology for the artificial retina chips, is introduced in detail. The concept, structure, fundamental performance,
operating principle, and processing functions for the fabricated artificial retinal chips are described. Applications including
interactive games by gesture-input are also introduced.
This work was presented, in part, at the International Symposium on Artificial Life and Robotics, Oita, Japan, February 18–20,
1996. 相似文献
105.
106.
Kazumasa Narumi Yoshikazu Fujii Kenji Kimura Michi-hiko Mannami 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》1994,90(1-4):266-269
The angular distributions and the energy spectra of scattered H+ ions are studied at glancing angle incidence of 30 keV H+ ions on the (001) surface of KCl single crystal. Discrete energy loss spectra of the scattered ions are observed. The observed exit angle distributions of the ions which have lost anomalous large amounts of energy at various angles of incidence do not depend on the angle of incidence. From the observed results, it is concluded that skipping motion occurs on the surface of KCl. 相似文献
107.
108.
Kazuhiro Morimoto Tatsuo Haruta Hideki Tojima Yoshikazu Takeuchi 《Drug development and industrial pharmacy》1995,21(17):1999-2012
Effects of saturated straight-chain fatty acids at various chain lengths (C8-C18) on the permeation of indomethacin, a relatively lipophilic compound and 6-carboxyfluorescein, a hydrophilic compound were examined using rat skins in in vitro. Furthermore, the disordering degrees of intercellular lipid domain in stratum corneum, which were treated by preparation containing saturated fatty acids were measured by FT-IR method using excised rabbit ear skins. Capric acid (C10), lauric acid (C12) and myristic acid (C14) within series of saturated fatty acids (0.07 M) showed the enhancing effects on the skin permeations of indomethacin and 6-CF. The permeation enhancing effects by these saturated fatty acids (C8-C18) except for capric acid (C10), were relative to the degrees of wavenumber shift in the frequency of the asymmetric CHbond stretching absorbance (2920 cm-1) on FT-IR spectra of the fatty acid treated stratum corneum. Therefore, the perturbation increase of lipid domain in stratum corneum by these fatty acids probably was the cause of the enhanced effects of permeation of indomethacin and 6-CF. On the other hand, capric acid appears to enhance the permeations of these two drugs by separate mechanisms. 相似文献
109.
Yasushi Tanaka Misao Namikawa Akira Hiura Xiao Fang Bi Yoshikazu Takada 《Electrical Engineering in Japan》1993,113(3):1-8
The magnetic properties of high-silicon steel sheets ranging in thickness from 0.35 to 0.03 mm and silicon content from 3 to 7.5 percent is investigated. The minimum iron losses are obtained with the silicon higher than 6.5 percent at the high-frequency range over 30 kHz. The sheet thickness dependency index m is estimated. The heat treatment effects to soft magnetic properties also are studied. 相似文献
110.
Hiroshi Uda Hideo Yonezawa Yoshikazu Ohtsubo Manabu Kosaka Hajimu Sonomura 《Solar Energy Materials & Solar Cells》2003,75(1-2):219-226
Polycrystalline CdS thin films have been deposited on borosilicate glass substrates coated with ITO film by metalorganic chemical vapor deposition using dimethyl cadmium and diethyl sulfide as source materials. The growth of CdS film occurred at substrate temperatures within the range of 280–360°C. The deposition rate increased with increasing VI/II molar ratio at any substrate temperature and showed a maximum value at the VI/II molar ratio of 4. The grain size of as-deposited CdS film prepared at substrate temperatures from 300°C to 360°C was about 0.1 μm. The CdS films consist of hexagonal form with a preferential orientation of the (0 0 2) plane parallel to the substrate. Thin CdS film with high optical transmittance was prepared at 350°C with the VI/II molar ratio of 4. The CdS film deposited by MOCVD may be used as a window layer for CdS/CdTe solar cell. 相似文献