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线路差动保护的相移制动能力研究 被引量:11
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作者 朱国防 陆于平 《中国电机工程学报》 EI CSCD 北大核心 2009年第10期84-90,共7页
数据同步是基于通信的差动保护方案的首要问题。为从差动保护判据本身找到一个减小同步误差影响的途径,提出描述差动保护判据耐同步误差能力的相移制动能力指标。采用相量分析法分析常规差动保护的相移制动能力,发现常规比率制动判据的... 数据同步是基于通信的差动保护方案的首要问题。为从差动保护判据本身找到一个减小同步误差影响的途径,提出描述差动保护判据耐同步误差能力的相移制动能力指标。采用相量分析法分析常规差动保护的相移制动能力,发现常规比率制动判据的相移制动能力只能达到20°左右,而非线性差动保护的相移制动能力可以达到60°左右,这对基于软实时通信技术的使用场合非常有价值。提出一种新相差型的差动保护判据,该判据采用制动系数来调整判据的灵敏度;采用保护动作边界角来调整判据的相移制动能力,是一种新型的非线性制动判据。仿真结果表明新判据具有良好的内部故障灵敏度、抗电流互感器(current transformer,CT)饱和能力和相移制动能力,是基于软实时通信技术的差动保护的理想选择。 展开更多
关键词 差动保护 数据同步 相移制动能力 相量分析法 非线性制动
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扇环型制动区差动保护算法 被引量:22
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作者 朱国防 陆于平 《电工技术学报》 EI CSCD 北大核心 2009年第11期172-177,共6页
同步误差在差动保护中表现为相移,同步误差引起的安全性问题可以用差动保护的相移制动能力描述。本文首先分析了传统比率制动判据的相移制动能力,发现获取良好的相移制动能力必须牺牲算法的灵敏度。为了适应弱同步环境,本文提出了一种... 同步误差在差动保护中表现为相移,同步误差引起的安全性问题可以用差动保护的相移制动能力描述。本文首先分析了传统比率制动判据的相移制动能力,发现获取良好的相移制动能力必须牺牲算法的灵敏度。为了适应弱同步环境,本文提出了一种新的差动保护判据,新判据分别从幅值和相角两个方面独立形成制动约束,从而可以合并解决电流互感器和同步误差引起的不平衡电流问题。新判据的制动区在ρ平面上呈现扇环形状,扇环内径决定了判据的灵敏度,扇环展开角度决定了判据的相移制动能力。仿真结果证明同步误差达到3ms时新判据能可靠制动,同时还能兼顾算法的灵敏度和电流互感器饱和时的安全性。 展开更多
关键词 分布式发电 差动保护 软实时通信 相移制动能力 扇环制动
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All-solid-state microscopic interferometer with frequency-variation and phase-shifting capability
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作者 TIAN Jin-dong ZHAO Xiao-bo PENG Xiang 《Optoelectronics Letters》 EI 2007年第2期123-125,共3页
A novel microscopic interferometry with ability of frequency-variation and phase-shifting is proposed for microstructures testing. By using acousto-optic technique, sequential carriers can be generated with different ... A novel microscopic interferometry with ability of frequency-variation and phase-shifting is proposed for microstructures testing. By using acousto-optic technique, sequential carriers can be generated with different spatial frequencies so that the temporal phase unwrapping method can be applied for decoding the height information. Combined with phase-shifting technique realized by spatial light modulator, this method is especially suitable for interferometric measurement with high precision and large dynamic range. 展开更多
关键词 全固态显微干涉仪 频率变异 相移能力 显微结构 测试
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Identification of the Interaction between P-Glycoprotein and Anxa2 in Multidrug-resistant Human Breast Cancer Cells 被引量:6
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作者 Hai-chang Zhang Fei Zhang +4 位作者 Bing Wu Jing-hua Han Wei Ji Yan Zhou Rui-fang Niu 《Clinical oncology and cancer researeh》 CAS CSCD 2012年第2期99-104,共6页
Objective To explore the interaction of Anxa2 with P-Glycoprotein (P-gp) in the migration and invasion of the multidrug-resistant (MDR) human breast cancer cell line MCF-7/ADR. Methods A pair of short hairpin RNA ... Objective To explore the interaction of Anxa2 with P-Glycoprotein (P-gp) in the migration and invasion of the multidrug-resistant (MDR) human breast cancer cell line MCF-7/ADR. Methods A pair of short hairpin RNA (shRNA) targeting P-gp was transfected into MCF-7/ADR cells, and monoclonal cell strains were screened. The expression of P-gp was detected by Western blot. Transwell chambers were used to observe the cell migration capacity and invasion ability. The interaction between P-gp and Anxa2 was examined by immunoprecipitation and immunofluorescence confocal microscopy analyses. Results P-gp expression was significantly knocked down, and there were notable decreasing trends in the migration and invasion capability of MDR breast cancer cells (P〈0.05). There was a close interaction between Anxa2 and P-gp. Conclusions MCF-7/ADR is an MDR human breast cancer cell line with high migration and invasion abilities. The knockdown of P-gp notably impaired the migration and invasion abilities of the tumor cells. The interaction of Anxa2 with P-pg may play an important role in time enhanced invasiveness of MDR human breast cancer cells. 展开更多
关键词 P-GLYCOPROTEIN Anxa2 drug resistance MULTIPLE neoplasm metastasis breast neoplasm
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Adsorptive potential of Acacia nilotica based adsorbent for chromium(Ⅵ) from an aqueous phase 被引量:1
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作者 Raza Khalid Zaheer Aslam +3 位作者 Aamir Abbas Waqar Ahmad Naveed Ramzan Reyad Shawabkeh 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第3期614-622,共9页
The objective of this research was to enhance adsorption capacity of Acacia nilotica (keekar) sawdust for the abatement of chromium bearing wastewater and to investigate the effect of process parameters on adsorptio... The objective of this research was to enhance adsorption capacity of Acacia nilotica (keekar) sawdust for the abatement of chromium bearing wastewater and to investigate the effect of process parameters on adsorption capacity. The sawdust was activated by acid wash and functionalized subsequently with formaldehyde. Functionalization of activated sawdust raised its chromium removal efficiency of almost 10% as compared to its adsorption removal efficiency of HCl treated sawdust in a batch adsorption study. Adsorption kinetic data provided better fitting with pseudo second order model. Maximum adsorption capacity calculated through the best fitting Langmuir model was 6.34 mg·g^-1 and 8.2 mg·g^-1 for HCl treated and formaldehyde functionalized sawdust adsorbents, respectively. The adsorption of Cr(VI) was endothermic when studied by varying temperature from 20℃ to 50℃ for both activated and functionalized adsorbents. 展开更多
关键词 Acacia nilotica Chromium Adsorption Kinetics Isotherms Thermodynamics
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Higher-Order Interactions: Understanding the knowledge capacity of social groups using simplicial sets 被引量:2
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作者 Bradford R GREENING Jr Noa PINTER-WOLLMAN Nina H FEFFERMAN 《Current Zoology》 SCIE CAS CSCD 2015年第1期114-127,共14页
A predominant benefit of social living is the ability to share knowledge that cannot be gained through the information an individual accumulates based on its personal experience alone. Traditional computational models... A predominant benefit of social living is the ability to share knowledge that cannot be gained through the information an individual accumulates based on its personal experience alone. Traditional computational models have portrayed sharing knowledge through interactions among members of social groups via dyadic networks. Such models aim at understanding the percolation of information among individuals and groups to identify potential limitations to successful knowledge transfer. How- ever, because many real-world interactions are not solely pairwise, i.e., several group members may obtain information from one another simultaneously, it is necessary to understand more than dyadic communication and learning processes to capture their full complexity. We detail a modeling framework based on the simplicial set, a concept from algebraic topology, which allows elegant encapsulation of multi-agent interactions. Such a model system allows us to analyze how individual information within groups accumulates as the group's collective set of knowledge, which may be different than the simple union of individually contained information. Furthermore, the simplicial modeling approach we propose allows us to investigate how information accumulates via sub-group interactions, offering insight into complex aspects of multi-way communication systems. The fundamental change in modeling strategy we offer here allows us to move from portraying knowledge as a "token", passed from signaler to receiver, to portraying knowledge as a set of accumulating building blocks from which novel ideas can emerge. We provide an explanation of relevant mathematical concepts in a way that promotes accessibility to a general audience [Current Zoology 61 (1): 114--127, 2015]. 展开更多
关键词 Collective decision making Communication Cultural transmission Information flow SIMPLEX Social learning
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