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101.
Iwao Shimizu Yuji Naito Iwao Yamaguchi Katsuyuki Kaiho Hitoshi Mizoguchi Satoru Yanabu 《Electrical Engineering in Japan》2008,164(1):52-61
Using conventional high‐temperature superconducting wire, a model superconducting fault current limiter (SFCL) is made and tested. Solenoid coil using Bi2223 silver sheath wire is so made that inductance is as small as possible and a vacuum interrupter is connected in series to it. A conventional reactor coil is connected in parallel. When the fault current flows in this equipment, superconducting wire is quenched and current is transferred into the parallel coil because of voltage drop of superconducting wire. This large current in parallel coil actuates magnetic repulsion mechanism of vacuum interrupter. Due to opening of vacuum interrupter, the current in superconducting wire is broken. By using this equipment, current flow time in superconducting wire can be easily minimized. On the other hand, the fault current is also easily limited by large reactance of parallel coil. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 52–61, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20315 相似文献
102.
Neuroimaging experiments have shown that prefrontal regions of the brain, which have the most age-related volume loss, are also the regions most likely to be more active in older adults than in younger adults. In an attempt to solve this puzzle, P. M. Greenwood (see record 2007-15625-001) has proposed a cascade that flows from age-related atrophy in the brain to changed processing strategies that result in plastic changes in regions adjacent and contralateral to the atrophic areas, culminating in greater functional activity. This hypothesis should stimulate research into these mechanisms and hopefully will ultimately inform researchers' ability to rehabilitate cognitive disorders in the elderly. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
103.
The formation of aluminum matrix composites fabricated by exothermic dispersion reaction in A1-TiO2-B2O3 system was investigated. The thermal analysis results show that the reactions are spontaneous and exothermic. The Gibbs free energy of α-Al2O3 is the lowest among all the combustion products, followed by TiB2 and Al3Ti. It is noted that when the B2O3/TiO2 mole ratio is below 1, the reaction products are composed of particle-like α-Al2O3, TiB2 and rod-like Al3Ti. The α-Al2O3 crystallites, resulting from the reaction between A1 and TiO2 or B2O3, are segregated at the grain boundaries due to a lower wettability with the matrix. SEM micrographs show that rod-like Al3Ti phase distributes uniformly in the matrix. When the BEO3/TiO2 mole ratio is around 1, the Al3Ti phase almost disappears in the composites, and the distribution of α-Al2O3 particulates is improved evidently. 相似文献
104.
申家字 《湖南工业职业技术学院学报》2008,8(6)
从人类文化发展的历史来看,文化的冲突与融合是一种规律。没有文化的冲突与融合,就没有文化的发展与创新。在世界全球化的进程中,各种文化间的冲突与融合已经成为不可避免的普遍现象。文化的核心是价值观。不同的文化有不同的价值观,文化的差异必然引起人们价值观的变化。在文化的冲突与融合过程中,冲突是必然的,但融合是主流。正是通过文化的交流和传播、文化适应和外来文化本土化以及文化转型等文化融合的主要方式,从而来对人们的道德观念、价值取向等产生深刻的影响。 相似文献
105.
Ring‐opening polymerization of D,L ‐lactide (LA) has been successfully carried out by using rare earth 2,6‐dimethylaryloxide (Ln(ODMP)3) as single component catalyst or initiator for the first time. The effects of different rare earth elements, solvents, monomers and catalyst concentration as well as polymerization temperature and time on the polymerization were investigated. The results show that La(ODMP)3 exhibits higher activity to prepare poly(D,L ‐lactide) (PLA) with a viscosity molecular weight of 4.5 × 104 g mol?1 and the conversion of 97 % at 100 °C in 45 min. The catalytic activity of Ln(ODMP)3 has following sequence: La > Nd > Sm > Gd > Er > Y. A kinetic study has indicated that the polymerization is first order with respect to both monomer and catalyst concentration. The apparent activation energy of the polymerization of LA with La(ODMP)3 is 69.6 kJ mol?1. The analyses of polymer ends indicate that the LA polymerization proceeds according to ‘coordination–insertion’ mechanism with selective cleavage of the acyl–oxygen bond of the monomer. Copyright © 2004 Society of Chemical Industry 相似文献
106.
Calculations and detailed first principle and thermodynamic analyses have been performed to understand the formation mechanism of K2Ti6O13 nanowires (NWs) by a hydrothermal reaction between bulk Na2Ti3O7 crystals and a KOH solution. It is found that direct ion exchange between K+ and Na+ plus H+ interactions with [TiO6] octahedra in Na2Ti3O7 promote the formation of an intermediate H2K2Ti6O14 phase. The large lattice mismatch between this intermediate phase and the bulk Na2Ti3O7 structure, and the large energy reduction associated with the formation of this intermediate phase, drive the splitting of the bulk crystal into H2K2Ti6O14 NWs. However, these NWs are not stable because of large [TiO6] octahedra distortion and are subject to a dehydration process, which results in uniform K2Ti6O13 NWs with narrowly distributed diameters of around 10 nm. 相似文献
107.
Business publications and the popular press have stressed the importance of creating conditions for meaningful employee expression in work roles, also known as engagement. Few empirical studies, however, have examined how individual or situational factors relate to engagement. Consequently, this study examines the interplay between employee age, perceived coworker age composition, and satisfaction with older (older than 55) and younger (younger than 40) coworkers on engagement using a sample of 901 individuals employed in the United Kingdom. Results indicated that satisfaction with one's coworkers related significantly to engagement. Moreover, perceived age similarity was associated with higher levels of engagement among older workers when they were highly satisfied with their coworkers over 55 and lower levels of engagement when they were not. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
108.
GAO Qinglu~ WU Bo~ GUO Guang~ .School of Management Wuhan University of Technology Wuhan China .School of Mechanical Engineering Huazhong University of Science Technology Wuhan China 《武汉理工大学学报》2006,28(Z2)
This article puts forward a scheduling method for nonlinear process plan shop floor.Task allocation and load bal- ance are realized by bidding mechanism.Though the agent interaction process,the execution of tasks is determined and the coherence of manufacturing decision is verified.The employment of heuristic index can help to optimize the system performance. 相似文献
109.
S135钻杆钢在钻井液中的氧腐蚀行为 总被引:4,自引:0,他引:4
基于系统的理论分析和现场腐蚀产物的XRD分析,揭示了S135钻杆钢在3%NaCl溶液中的氧腐蚀机理。为研究腐蚀因素与腐蚀速率的关系,通过室内高压釜动态模拟实验,分别研究了钻井液中含氧量、钻井液温度、钻井液流速和钻井液盐浓度对S135钻杆钢的氧腐蚀速率影响规律。实验研究结果表明(1)3%NaCl盐水钻井液对S135钻杆钢的腐蚀主要是氧去极化作用所致;(2)钻井液含氧量和钻井液流速的增加会加快钻杆钢的氧腐蚀速率,而钻井液温度和含盐量对钻杆钢的氧腐蚀速率具有双重作用。 相似文献
110.