Results 241 to 250 of about 1,140 (275)
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A Ring Resonator System for Ground Subsurface Sensing
Subsurface Sensing Technologies and Applications, 2000A circular ring placed parallel above the ground surface is analyzed. The analysis, based on transmission-line modeling, shows how the structure can be utilized for ground conductivity sensing purposes. It is shown that, once the operating frequency is tuned to a half wavelength resonance, the information on the amplitude ratio of two voltages (or two ...
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Energy to peak control of LPV systems with application to rotorcraft ground resonance
Proceedings of the 2001 American Control Conference. (Cat. No.01CH37148), 2001Energy to peak control problem for linear parameter varying (LPV) systems involves the design of a stabilizing controller that guarantees satisfaction of time domain L/sub /spl infin// constraints for all bounded energy disturbances and admissible parameter trajectories.
Ravi K. Prasanth +3 more
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Ground and air resonance characteristics of a soft in-plane rigid-rotor system
VTOL Research, Design, and Operations Meeting, 1969A flight research program was conducted on a soft in‐plane matched‐stiffness rotor in which it was demonstrated that a soft in‐plane rigid rotor is subject to mechanical instability in flight as well as on the ground. The research included extending existing analysis techniques to include aerodynamic forces.
R. E. Donham +2 more
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Characteristic analysis of single-phase grounding fault in resonant grounded systems based-on HHT
2016 IEEE 11th Conference on Industrial Electronics and Applications (ICIEA), 2016Transient analysis is carried out for the single-phase grounding fault in small current grounding system, the transient grounding current expression is derived, and the influence factors are analyzed. Introduces a method for non-stationary and non-linear signal analysis method-Hilbert Huang transform (HHT) to analyze the single phase grounding fault in
Yingwei Xiao +3 more
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Grounding Failure Detection Based on Wavelets Method in Resonant Grounded Power Distribution System
2010 Second WRI Global Congress on Intelligent Systems, 2010This paper analyses characteristics of single-phase ground fault and presents a fault line selecting method based on wavelet transform. Base on Sampling frequency, it selects the special frequency band, the singularity detection with wavelet is employed to obtain the polarities and magnitudes of the abrupt of current, and through comparing the ...
Yusheng Zhou +4 more
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2012 International Conference on Lightning Protection (ICLP), 2012
A joint research project between AES Sul, the Federal University of Itajuba and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a resonant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost.
BORGHETTI, ALBERTO +5 more
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A joint research project between AES Sul, the Federal University of Itajuba and the University of Bologna aims at defining the required protections against lightning-originated overvoltages in a resonant grounded distribution system in order to achieve the adequate lightning performance level with minimum cost.
BORGHETTI, ALBERTO +5 more
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Systems with resonating-valence-bond ground states: Correlations and excitations
Physical Review B, 1988We 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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Power system resonance excited by VFD ground fault
2009 IEEE International Electric Machines and Drives Conference, 2009This 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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Resonance Analysis of Small Current Grounding System in Distribution Network
2018 China International Conference on Electricity Distribution (CICED), 2018At 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 +5 more
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, 2019