Publications associées à Théorème d'Earnshaw

Laser Doppler Vibrometer measurements of the 3D pressure field for the estimation of the radiation force produced by an acoustic standing-wave levitator

Acoustic levitation devices use powerful ultrasonic standing waves to levitate objects in mid-air. We have created a system and method to measure the full harmonic content of the acoustic field accurately. Our study revealed that levitated particles alter ...

Elsevier Science Sa2024

Spatiotemporal energy‐density distribution of time‐reversed electromagnetic fields

Farhad Rachidi-Haeri, Marcos Rubinstein, Hamidreza Karami, Elias Per Joachim Le Boudec, Nicolas Mora Parra

Time reversal exploits the invariance of electromagnetic wave propagation in reciprocal and lossless media to localize radiating sources. Time-reversed measurements are back-propagated in a simulated domain and converge to the unknown source location. The ...

2024

Principles and Test Result of Novel Full Passive Magnetic Levitation Motor with Diamagnetic Disk

Hannes Bleuler

This paper proposes a novel full passive magnetic levitation motor without active magnetic suspension. It has a magnetic levitation unit and a motor unit. The Halbach array permanent magnets and a pyrolytic graphite (PG) disk realize the full passive magne ...

IEEE2021

Experimental verification of X-point potential well formation in unfavorable magnetic field direction

Basil Duval, Holger Reimerdes, Christian Gabriel Theiler, Joaquim Loizu Cisquella, Marco Wischmeier, Mirko Wensing, Cedric Kar-Wai Tsui, Claudia Colandrea, Hugo De Oliveira, Sophie Danielle Angelica Gorno

Recent TCV experiments confirm the predicted formation of an electric potential well, below the magnetic X-point, in configurations with unfavorable

B_t

field direction (ion

\nabla B

drift away from the divertor), that substantially reshapes the typica ...

Elsevier2020

Speed and Stability Limits for High-Speed Bearingless Disc Drives

Yves Perriard, Douglas Martins Araujo, Juan Patricio Tomás Peralta Fierro

Increasing material costs and emerging applications have steered research trends towards compacter and therefore faster drives. The arising challenges of miniaturization have made contactless magnetic levitation increasingly attractive, which offer practic ...

IEEE2018

Spin Diffusion in Dynamic Nuclear Polarization Nuclear Magnetic Resonance

Arthur César Pinon

Dynamic Nuclear Polarization (DNP) is currently one of the most efficient ways of enhancing sensitivity in solid-state Nuclear Magnetic Resonance (NMR) experiments. The DNP protocol consists in doping a sample with a small amount of paramagnetic species, t ...

EPFL2018

Realization of a Diamagnetically Levitating Rotor Driven by Electrostatic Field

Hannes Bleuler, Yuanping Xu, Qingwen Cui, Ryosuke Kan, Jin Zhou

In this paper, a novel configuration of frictionless diamagnetic levitation combined with electrostatic glass motor is presented. A 12.5 mm diameter disc shaped rotor comprised of pyrolytic graphite and glass is fabricated. The rotor disc is levitated stab ...

Institute of Electrical and Electronics Engineers2017

Stabilization of electrodynamic bearings with active magnetic dampers

Qingwen Cui

Electrodynamic Bearings (EDBs) are a kind of passive magnetic bearings that exploits the interaction between the induced eddy currents in a conductor and a magnetic field to provide re-storing forces. They have been regarded as an appealing alternative to ...

EPFL2016

Transverse spin penetration length in metallic spin valves

Jean-Philippe Ansermet

A semiclassical description of diffusive spin transport in spin valves, which takes into account the transverse components of spin accumulation, is used to calculate the second harmonic voltage response to a low-frequency current. The description is applie ...

American Institute of Physics2013

Diamagnetic thresholds for sawtooth cycling in tokamak plasmas

Federico David Halpern

The cycling dynamics of the internal kink mode, which drives sawtooth oscillations in tokamak plasmas, is studied using the three dimensional, non-linear magnetohydrodynamic (MHD) code XTOR-2F [H. Lütjens and J.-F. Luciani, J. Comput. Phys. 229, 8130 (2010 ...

American Institute of Physics2011

Ferrimagnetism of the magnetoelectric compound Cu2OSeO3 probed by Se-77 NMR

Jean-Philippe Ansermet, Frédéric Mila, Helmuth Berger

We present a thorough Se-77 nuclear-magnetic-resonance (NMR) study of a single crystal of the magnetoelectric compound Cu2OSeO3. The temperature dependence of the local electronic moments extracted from the NMR data is fully consistent with a magnetic phas ...

2010

Modeling and Control of a Magnetically Levitated Planar Motor

Alireza Karimi, Roland Longchamp, Marc Kunze, Vincent Reymond

This paper deals with the modeling and control of a magnetically levitated planar motor. The actuator considered has moving coils and stationary magnets. The principal objective is to develop a model which can be implemented in simulation. Therefore, the d ...

2009

Transport and magnetic properties of BaVSe3

László Forró, Helmuth Berger, Ana Akrap, Vladan Stevanovic, Neven Barisic

We report a comprehensive study of transport, magnetotransport, and magnetic properties of single crystals of BaVSe3. The paramagnetic metal-ferromagnetic metal transition at 43 K was followed as a function of pressure by measuring the electrical resistivi ...

2008

Acceleration and inclination sensors based on magnetic levitation : application in the particular case of structural health monitoring in civil engineering

François Barrot

Some fields such as the Monitoring of Civil Engineering Structures, need very sensitive acceleration and inclination sensors with a high resolution at low accelerations (typically less than 1G) and moderate frequencies (typically less than 20 Hz) or very s ...

EPFL2008

Preliminary Investigations on a Diamagnetically Levitated Linear Conveyor

Hannes Bleuler, Roland Moser, Dominique Chapuis, François Barrot, Laurent Sache, Thomas Bosgiraud

Diamagnetic levitation is the only passive levitation at room temperature. It is interesting to use this principle for a contactless conveyor in applications where friction and wear-particle contamination should be avoided such as in a microfactory. Using ...

2006

Position Controlled Diamagnetic Linear Conveyor

Hannes Bleuler, Dominique Chapuis, François Barrot, Thomas Bosgiraud, Benjamin Burns

Magnetic levitation is an interesting concept in applications where friction and wear-particle contamination should be avoided. In this respect, a former study has shown that diamagnetic levitation, in conjunction with an electrodynamic impulse drive, is a ...

2006

Linear stability analysis of microinstabilities in electron internal transport barrier non-inductive discharges

Olivier Sauter, Yann Camenen, Alberto Bottino, Emiliano Fable

The role of the current profile and ion and electron temperature ratio in Tokamak A Configuration Variable (TCV) electron internal transport barrier (eITB) noninductive discharges is inspected by means of the linear gyrokinetic global code LORB5 (Bottino e ...

2006

Two dimensional magnetic manipulation of microdroplets on a chip

Martinus Gijs, Ulrike Lehmann, Virendra Kumar Parashar

In this paper we describe the two-dimensional (2D) magnetic manipulation of aqueous droplets suspended in silicone oil over the chip surface. The magnetic actuation is based on the force imposed on superparamagnetic microparticles inside the droplets. Thes ...

2005

Two dimensional magnetic manipulation of microdroplets on a chip

Martinus Gijs, Ulrike Lehmann, Amar Rida, Virendra Kumar Parashar

In this paper we describe the two-dimensional (2D) magnetic manipulation of aqueous droplets suspended in silicone oil over the chip surface. The magnetic actuation is based on the force imposed on superparamagnetic microparticles inside the droplets. Thes ...

2005