Results 211 to 220 of about 1,030 (244)

Systems with resonating-valence-bond ground states: Correlations and excitations

Physical Review B, 1988
We consider a resonating-valence-bond state as a variational estimate for the ground state of a Heisenberg antiferromagnet. We derive an expression for the normalization of this wave function, which is a superposition of a very large number of singlet pair states, which we then use to show that the singularities, correlations, and low-lying excitations
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Analysing the feature of instantaneous positive sequence network when single-phase grounding in resonant grounding system

Proceedings of 2011 International Conference on Electronic & Mechanical Engineering and Information Technology, 2011
Establishing the mathematical model of instantaneous positive sequence network of power source, grounding petersen coil, ground point, capacitance to the ground to the 10 kV medium-voltage resonance grounding system with instantaneous symmetrical component, establishing the mathematical model of instantaneous positive sequence network to resonance ...
Xuejie Chen, Zhouxing Fu, Jianwen Zhao, Shangbin Sun, Haidong Chen, Ran Yu 0003   +5 more
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Microwave resonance effects in paramagnetic singlet-ground-state systems

AIP Conference Proceedings, 1975
EPR in the excited Γ5(2) triplet state of Tm3+ in cubic TmP has been studied. From the temperature dependence of the g‐value, it was found that the fourth‐order term dominates in the crystal‐field, and the exchange interaction between Tm3+ ions is weakly antiferromagnetic.
K. Sugawara, C. Y. Huang, B. R. Copper
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Power system resonance excited by VFD ground fault

2009 IEEE International Electric Machines and Drives Conference, 2009
This paper investigates the resonance phenomenon produced by a voltage source PWM variable frequency drive (VFD) on an ungrounded delta system. Many drives are installed on ungrounded delta systems without isolation transformers or other means to provide inverter ground reference.
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A novel fault line selection method of resonant grounding system

2017 IEEE Conference on Energy Internet and Energy System Integration (EI2), 2017
In order to solve the problems of fault line selection in resonant grounding system, a novel fault line selection method for distribution network was proposed in this paper. First, continuously measure three-phase voltage and zero-sequence voltage, which detects single-phase ground fault.
Yongjun Yuan, Xiaogang Chen, Lei Yang, Xiangjun Zeng, Jun Cai, Minqi Yu   +5 more
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The research and realization of the low-voltage simulation for the resonant grounded system

2012 China International Conference on Electricity Distribution, 2012
In order to study operational features of resonant grounded system deeply, and test all performance indexes of the control device of arc-suppression coil, this paper comes up with the research ideas and implementation of the low-voltage simulation environment, describing its technology parameters and building principles of the major parts in detail ...
null Qiu Jixing, null Wang Qiang, null Fan Yanwei, null Yu Ling   +3 more
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Resonance Analysis of Small Current Grounding System in Distribution Network

2018 China International Conference on Electricity Distribution (CICED), 2018
At present, there are a large number of arc suppression coil grounding mode in the low-voltage distribution network for the equipment insulation and power supply reliability considerations. The role of arc suppression coil grounding mode is when the grid single-phase ground fault occurs, arc suppression coil will provide inductor current to compensate ...
Zhou Desheng, Zou Xiaofeng, Xu Jie, Song Jie, Du Zhaoxin, Zeng Ping   +5 more
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Practical Experiences with Resonant Grounding in a Large 34.5-Ky System

Transactions of the American Institute of Electrical Engineers, 1950
A large 34.5-kv system was operated ungrounded until early in 1946, at which time resonant grounding was installed, since it promised to be the most effective and most economical method of improving reliability of service. The layout of the system and a description of tests with the groundfault neutralizer installed are given. Records ords of operation
Harold H. Brown, Eric T. B. Gross
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Multiband non-resonant antenna system with reduced ground clearance

2017 11th European Conference on Antennas and Propagation (EUCAP), 2017
Small and multiband antennas are crucial elements for wireless devices. On one hand, the space devoted to the antenna is small due to the presence of other electronic components in the device. On the other hand, the number of frequency bands with the inclusion of 4G is relevant.
Andujar, Aurora, Anguera, Jaume, Mateos, Rosa   +2 more
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First resonant neutral grounding implantation in Spanish distribution system

2001 IEEE Porto Power Tech Proceedings (Cat. No.01EX502), 2002
Changing the earthing system of medium voltage networks is a complex operation. It is necessary to take into account all the various technical aspects of the totality of the equipment involved in this process. Frequently, considerable additional economic investment is required as a result of this analysis of technical aspects.
A.J. Mazon, I. Zamora, L. Zabala, F. Antepara, J. Amantegui, J.R. Saenz   +5 more
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