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排序方式: 共有603条查询结果,搜索用时 31 毫秒
131.
132.
Katsumi Yamazaki Haiyan Yui Hideki Ohguchi Masao Shuto 《Electrical Engineering in Japan》2019,208(1-2):53-62
In this paper, we investigate the losses caused by circulating currents generated in armature windings of permanent magnet synchronous machines by using electromagnetic field analysis. In the analysis, each parallel connected wire in the windings is modeled by finite elements in order to consider the difference in the electromotive forces and the generation of the circulating currents. The calculated losses are compared with experimental results. It is clarified that the armature copper loss in permanent magnet machines with parallel connected wires considerably increases by the circulating currents. 相似文献
133.
Terushige Fujii Haruo Kawasaki Shinichi Tooyama Katsumi Sugimoto Hitoshi Asano 《亚洲传热研究》2005,34(8):564-578
The two‐phase flow thermal control system, using latent heat of the internal fluid, has received a great deal of research interest as a method for heat removal on the space station and the Space Solar Power System (SSPS). The system has a much lower weight than the single‐phase flow, and the temperature can be accurately controlled by changing the saturated pressure inside the loop. To date, this system has not been put into practical use. Numerical analyses were therefore used to investigate the dynamic responses of the loop and to investigate the operational characteristics of the thermal control system. A simulation model was constructed, and the results of the numerical analysis were compared with the experimental results. Good agreement was obtained between analytical and experimental results. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(8): 564–578, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20090 相似文献
134.
Katsumi Kurita Mikito Kezuka Shigeru Aoki Yuuj i Nakanishi Kazutoshi Tominaga Mitsuo Kanazawa 《土木工程与建筑:英文版》2014,(3):261-267
In this study, dynamic characteristics of the small base isolation system using new friction bearings are investigated by excitation experiment, and compared to other one using previous bearings. Peak amplitude of the acceleration response waves on the small base isolation system is decreased to about 10%-25% compared to the input waves. Also root mean square amplitude is decreased to about 10%-40%. In case of the ball embedded a cylindrical sponge, the new bearing, the damping ratio increases with increasing width of the cylindrical sponge. The natural frequency does not change. On the other hand, in case of the marble plate that is previous bearing, the damping ratio increases with increasing curvature radius of the marble plate, the natural frequency also increases. Therefore, the small base isolation system using new friction bearing provides better performance. The responses of the base isolation system indicate nonlinier effects by friction force. 相似文献
135.
Hideki Hyuga Mark I. Jones Kiyoshi Hirao Yukihiko Yamauchi Katsumi Yoshida Hideki Kita 《Journal of the American Ceramic Society》2008,91(1):192-197
The wear behavior of Si3 N4 ceramics sintered with various rare earth additives was studied for nonlubricated sliding under different conditions, and scratch tests carried out in an attempt to correlate the wear behavior. When multiple scratch testing is used the results can be used to indicate the initial wear behavior under fracture-dominated wear of the materials. The additive system used in the sintering of the Si3 N4 ceramics affected the specific wear rate under nonlubricated sliding conditions, and under high load conditions, where fracture is dominant, the specific wear rate was shown to increase in samples sintered with lutetium as a consequence of a strong bonding strength between the grains and grain boundary resulting in a higher degree of brittle fracture. 相似文献
136.
Jingtao Xu Jun Tang Kazumi Sato Yoichi Tanabe Satoshi Heguri Hitoshi Miyasaka Masahiro Yamashita Katsumi Tanigaki 《Journal of Electronic Materials》2011,40(5):879-883
The heat capacity of single-crystalline samples of Sr8Ga16Ge30 (SGG) and Ba8Ga16Ge30 (BGG) clathrates was measured to investigate the anharmonicity of the encapsulated atoms. At low temperatures, BGG can be
well described by a standard Debye model, and the C
p/T
3 versus T plot can be fitted with two Einstein temperatures: θ
E1 = 42 K and θ
E2 = 74 K. On the other hand, SGG shows deviation from the Debye model. Moreover, neither the Einstein model nor the soft potential
model (SPM) alone can fit the peak in the C
p/T
3 versus T plot, and the peak should be fitted by employing both models. Our results indicate that the effective electron mass is enhanced
by the anharmonic phonons. 相似文献
137.
Five kinds of fucoidans from the brown seaweeds Cladosiphon okamuranus, Sargassum hornery, Kjellmaniella crassifolia (Saccharine sculpera), Nemacystus decipiens, and Fucus vesiculosus, were isolated according to a previously reported procedure with slight modification. The scavenging activities of DPPH radical, superoxide radical, and hydroxyl radical, as well as the ORAC value were measured for the isolated fucoidans. Fucoidans from S. hornery, F. vesiculosus, and K. crassifolia showed higher antioxidant activity than that from S. hornery and C. okamuranus, except for the hydroxyl radical scavenging activity. The relationship between the antioxidant activity and the structure was examined for each fucoidan. Fucoidans with high amount of sulfate groups did not necessarily result in increased antioxidant activity, although the sulfate group itself was essential for the antioxidant activity. Furthermore, the fucoidan linked to a side chain monosaccharide, such as GlcA, demonstrated similar antioxidant activity. The antioxidant activity of the fucoidans was possibly due to a combination of the factors involved, such as the amount of sulfate groups, the position of the sulfate groups, the kind of side chain sugar, the linkage of a side chain sugar, and the molecular weight. 相似文献
138.
139.
Wesley Pontes Walter Katsumi Sakamoto Mauro Henrique de Paula Marcelo A. A. Sanches Ricardo L. B. de Freitas 《仪器科学与技术》2013,41(3):210-219
A PZT detector is used for measuring the energy fluence rate of X-ray pulses produced by superficial cancer therapy equipment (orthovoltage range). The instrument consists of a pyroelectric sensor, a low-noise high-sensitivity, current-to-voltage converter, a microcontroller and a digital display. The main element of the instrument is a pyroelectric sensor which consists of an iron-doped lead zirconate titanate ceramic disk. The response of the instrument exhibits a nonlinear relationship with the energy fluence rate of the radiation and the precision is better than 3%. The equipment is inexpensive, rugged, simple to construct, and has good long-term stability. 相似文献
140.
To examine the influence of phosphorus on the commercial V2O5(WO3)/TiO2 SCR catalyst, measurements were carried out by means of infrared and Raman spectroscopy, XPS, and NO reduction measurement as a function of phosphorus loading. Phosphorus added to the catalyst was found to disperse well over the catalyst without a significant agglomeration up to 5 wt% P2O5 addition. The number of the hydroxyl groups bonded to the vanadium and titanium species decreased readily with increasing amount of phosphorus. Correspondingly, the hydroxyl groups bonded to the phosphorus species were formed. NH3 adsorbed on both hydroxyl groups bonded to vanadium and phosphorus as ammonium ions, implying that the P–OH groups formed are also responsible for the Brønsted acidity. The NO reduction activity was found to be decreased with increasing amount of phosphorus; however, the influence of phosphorus was relatively small irrespective of the large amount of phosphorus addition. The deactivation might be caused by the change in the nature of the surface hydroxyl groups as Brønsted acid sites. Phosphorus species might partially wrap the surface V=O and W=O groups, which might also contribute to the deactivation. 相似文献