Results
author = "Lemarquand, Guy"
Magnetic Field in MRI Yokeless Devices: Analytical Approach
Description :
This paper presents a three-dimensional analytical expressions for studying the static magnetic field produced by Magnetic Resonance Imaging structures. This medical imaging technique uses a very high and uniform magnetic field produced by ring permanent magnets with rotating polarizations. However,...
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English
COMPARISON OF THE COULOMBIAN AND AMPERIAN CURRENT MODELS FOR CALCULATING THE MAGNETIC FIELD PRODUCED BY RADIALLY MAGNETIZED ARC-SHAPED PERMANENT MAGNETS
Description :
This paper presents some improved analytical expressions of the magnetic field produced by arc-shaped permanent magnets whose polarization is radial with the amperian current model. First, we show that the radial component of the magnetic field produced by a ring permanent magnet whose polarization ...
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English
Analytical Expressions of the Magnetic Field Created by Tile Permanent Magnets of Various Magnetization Directions
Description :
This paper presents a thorough study of the magnetic field created by tile permanent magnets uniformly magnetized in air. To do so, we use the coulombian model for determining the analytical expressions of the three magnetic field components created by the tile magnets. Moreover, various magnetizati...
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English
MAGNETIC COUPLINGS WITH CYLINDRICAL AND PLANE AIR GAPS: INFLUENCE OF THE MAGNET POLARIZATION DIRECTION
Description :
This paper presents a comparison of cylindrical and plane air gap magnetic couplings in which the tile permanent magnet polarizations can be either radial or tangential or axial. The expressions of the torque transmitted between the two rotors of each coupling are determined by using the colombian a...
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English
MAGNETIC FIELD PRODUCED BY A PARALLELEPIPEDIC MAGNET OF VARIOUS AND UNIFORM POLARIZATION
Description :
This paper deals with the modeling of parallelepipedic magnets of various polarization directions. For this purpose, we use the coulombian model of a magnet for calculating the magnetic potential in all points in space. Then, we determine the three components of the magnetic field created by a paral...
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Language(s) :
English
IRONLESS LOWFREQUENCY LOUDSPEAKER WORKING UNDER ITS RESONANCE FREQUENCY
Description :
A soon achieved low frequency loudspeaker (10 Hz to 100 Hz) is described. To suppress the non-linearities and the drawbacks due to the motor, its structure is totally ironless. The large flat diaphragm and the high force factor of the loudspeaker lead to its high efficiency. Efforts have been made f...
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English
Calculation Method of Permanent Magnet Pickups for Electric Guitars
Description :
This paper first presents the structures of permanent magnet pickups for electric guitar and the considered device: string, magnet, coil. It then describes a method to calculate the induced electromotive force (EMF) in the pickup coil when the string moves. The method of calculation links the EMF in...
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English
Nonlinear Intermodulation of two Coherent Acoustic Progressive Waves Emitted by a Large Bandwidth Loudspeaker.
Description :
The main purpose of the paper is to contribute at presenting a formalism which would be relevant for interpreting qualitatively the nonlinear harmonic distortion, and more particularly the strong intermodulation, which occur in air in the frequency range (20 Hz-20 kHz) when the vawe is propagating. ...
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English
Motor Nonlinearities in Electrodynamic Loudspeakers: Modelling and Measurement
Description :
This paper studies the motor nonlinearities of a classical electrodynamic loudspeaker. Measurements show the dependence of the voice-coil inductance with its position and with the driving current as well as the force factor dependence on the coil position. They allow the tuning of the parameters of ...
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Language(s) :
English
Modeling of the nonlinear distortion in electrodynamic loudspeakers caused by the voice-coil inductance
Description :
The electrodynamic loudspeaker is a strongly nonlinear system. The main causes of nonlinearity are the nonlinear stiffness of the suspensions and the nonuniform distribution of the magnetic flux density along the air gap in the magnetic circuit. A third cause, the nonlinear voice-coil inductance is ...
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HAL - Hyper Article on Line
Language(s) :
French