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排序方式: 共有1208条查询结果,搜索用时 15 毫秒
991.
Hiromi Yamashita Shinichi Kawasaki Yuichi Ichihashi Masato Takeuchi Masaru Harada Masakazu Anpo Catherine Louis Michel Che 《Korean Journal of Chemical Engineering》1998,15(5):491-495
Titanium-silicon (Ti/Si) binary oxides having different Ti content were prepared by the sol-gel method and utilized as photocatalysts
for the hydrogenation and hydrogenolysis of CH2CCH with H2O. The photocatalytic reactivity and selectivity of these catalysts were investigated as a function of the Ti content and
it was found that the hydrogenolysis reaction (C2H6 formation) was predominant in regions of low Ti content, while the hydrogenation reaction (C3H6 formation) proceeded in regions of high Ti content. The in situ photoluminescence, diffuse reflectance absorption, FT-IR,
XAFS (XANES and EXAFS), and XPS spectroscopic investigations of these Ti/Si binary oxides indicated that the titanium oxide
species are highly dispersed in the SiO2 matrices and exist in a tetrahedral coordination exhibiting a characteristic photoluminescence spectrum. The charge transfer
excited state of the tetrahedrally coordinated titanium oxide species plays a significant role in the efficient photoreaction
with a high selectivity for the hydrogenolysis of CH3CCH to produces mainly C2H6 and CH4, while the catalysts involving the aggregated octahedrally coordinated titanium oxide species show a high selectivity for
the hydrogenation of CH3CCH to produce C3H6, being similar to reactions of the powdered TiO2 catalysts. The good parallel relationship between the yield of the photoluminescence and the specific photocatalytic reactivity
of the Ti/Si binary oxides as a function of the Ti content clearly indicates that the high photocatalytic reactivity of the
Ti/Si binary oxides having low Ti content is associated with the high reactivity of the charge transfer excited state of the
isolated titanium oxide species in tetrahedral coordination, [Ti3+-O−]*. 相似文献
992.
Shinichiro Hori Kazurou Harada Yoshiyuki Ishihara Toshiyuki Todaka 《Electrical Engineering in Japan》2005,150(3):11-18
This paper presents a study on iron loss characteristics of an amorphous magnetic material under nonsinusoidal wave magnetic flux. The iron loss characteristics of the amorphous magnetic material have been compared to those of grain‐oriented magnetic steel sheets. Measurements of the iron loss have been carried out by means of an SST. It was found that the ratio of the iron loss increase of the amorphous magnetic material under the excitation by distorted waveforms and symmetric PWM waveforms is lower than that of grain‐oriented magnetic steel sheets. On the other hand, the ratio of the iron loss increase of the amorphous magnetic material under the excitation by asymmetric PWM waveforms is higher than that of grain‐oriented magnetic steel sheets. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(3): 11–18, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20004 相似文献
993.
Y Kawanishi S Harada H Tachikawa T Okubo H Shiraishi 《Canadian Metallurgical Quarterly》1998,81(5):434-439
Dysfunction of serotonin systems has been implicated in schizophrenia. In the present study, the human 5-HT1A receptor gene containing the 5' untranslated region was screened in order to detect genetic variations, through which alteration of protein function or level of expression might contribute to schizophrenia. Genomic DNAs were isolated from whole-blood samples of 61 unrelated schizophrenic patients and 100 healthy controls. Genetic variations were screened systematically by single-strand conformational polymorphism (SSCP) analysis, followed by direct sequencing of polymerase chain reaction (PCR) product as well as restriction fragment-length polymorphism (RFLP). The novel mutations (-51T --> C, -152C --> G, -321G --> C, -480delA, and -581C --> A) were found in the 5' untranslated region. Furthermore, we found a novel missense mutation (Gly272Asp) in the coding region in addition to the mutations (Pro16Leu, 294G --> A, and 549C --> T) reported previously. No significant differences in genotype frequencies as well as allele frequencies were found between patients and controls. Our data provided no evidence of association between schizophrenia and the variants in the 5' untranslated region as well as the coding region of the human 5-HT1A receptor gene. 相似文献
994.
K. Tomari T. Harada Z. Maekawa H. Hamada M. Iwamoto A. Ukai 《Polymer Engineering and Science》1993,33(15):996-1001
Weldlines are fatal defects in many injection moldings of thermosetting resins and thermoplastics. Significant strength reduction by weldlines in thermoplastics is caused by poor adhesion, molecular orientation, and a V-notch effect. These factors have been little investigated in detail, in spite of being well known. In the present article, the V-notch effect on strength is discussed for two types of thermoplastics, polystyrene and polycarbonate. The depth of weldlines was obtained by milling on the weldline surface, and the fracture toughness was measured with a double edge notched specimen. Polystryrene, which was drastically weakened by weldlines, had relatively deeper V-notch regions and the fracture toughness was also reduced by weldlines. Although polycarbonate had the same fracture toughness as polystyrene, it had strong weldlines since the depth of weldlines was negligibly small. 相似文献
995.
996.
Harada Y. Hioe W. Takagi K. Kawabe U. 《Applied Superconductivity, IEEE Transactions on》1994,4(2):97-106
A novel processor with micro-pipelined architecture is proposed for latch-type Josephson logic devices. The processor is segmented into several operating stages activated by a multi-phase power system. Independent register groups are allocated to each stage in order to support pipeline processing of several instruction streams. This architecture allows building of a fine pipeline pitch processor which is capable of MIMD processing. A 12-bit micro-pipelined Josephson processor, containing an ALU, a multiplier and 16 registers, is described. Driven by a 3-phase AC power system, it is able to process 4 instruction streams simultaneously. A pipeline pitch of 3.3 GHz is expected using conventional Josephson device technology. A 4-bit processor design for 12-bit data length is also discussed 相似文献
997.
998.
999.
Tanaka T. Ohki Y. Ochi M. Harada M. Imai T. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2008,15(1):81-89
Frequency accelerated partial discharge (PD) aging of epoxy nanocomposite with 5 wt % additions of clay was investigated in comparison with that of epoxy without clay in terms of PD erosion depth. It was found that the change in the erosion depth is far smaller in specimens with clay than those without clay. The newly developed organic modification and solubilization methods give comparable PD resistance characteristics. The latter would be more resistant to PD's than the former, if specimens were prepared properly. It was clarified that nano-micro mixed composites were superior to the single nanocomposite. Nano segmentation with some interaction zone effect is proposed as a mechanism of improvement in PD resistance. 相似文献
1000.
Tsutomu Osawa Shinobu Oishi Masako Yoshihisa Miho Maegawa Tadao Harada Osamu Takayasu 《Catalysis Letters》2005,102(3-4):261-264
The enantio-differentiating hydrogenation of methyl acetoacetate was carried out over a (R,R)-tartaric acid-NaBr-modified reduced Ni catalyst. Reduced Ni was pre-modified in a methanol solution of tartaric acid and NaBr. It was revealed that the pre-treatment of methanol by molecular sieves was essential for attaining the high enantio-differentiating ability of 80–90% and high durability during repeated uses of the recovered catalyst. 相似文献