1,056 research outputs found
Highly confined Love waves modes by defect states in a holey SiO2 /quartz phononic crystal
Highly confined Love modes are demonstrated in a phononic crystal based on a
square array of etched holes in SiO 2 deposited on the ST-cut quartz. An
optimal choice of the geometrical parameters contributes to a wide stop-band
for shear waves' modes. The introduction of a defect by removing lines of holes
leads to the nearly flat modes within the band gap and consequently paves the
way to implement advanced designs of electroacoustic filters and
high-performance cavity resonators. The calculations are based on the finite
element method in considering the elastic and piezoelectric properties of the
materials. Interdigital transducers are employed to measure the transmission
spectra. The geometrical parameters enabling the appearance of confined cavity
modes within the band gap and the efficiency of the electric excitation were
investigated
Micro-systèmes et contrôle d'écoulements
Les micro-systèmes magnéto-mécaniques
présentent des possibilités intéressantes en matière de contrôle d'écoulements. Ils
permettent de remplir les cahiers des charges des constructeurs aéronautiques ou
automobiles. Ils sont également plus facilement intégrables sur les prototypes que les
MEMS issus de microtechnologies entièrement intégrées. On présentera quelques tests en
soufflerie. Les effets sur les écoulements seront discutés et les perspectives
tracées
Multilayer modeling of thermoacoustic sound generation for thermophone analysis and design
International audienc
E -tunable magnetic susceptibility and reversible magnetization switching in YIG/Pt/PMN-PZT/Pt heterostructure by low electric and magnetic fields
International audienc
A millimeter-wave inflatable frequency-agile elastomeric antenna
This letter reports a millimeter-wave frequency agile microstrip antenna printed on an ultrasoft elastomeric PDMS substrate. The microstrip patch antenna is supported by a PDMS membrane suspended over an air cavity. The distance H between the patch and the ground plane, and thus the resonant frequency of the antenna, are tuned using pneumatic actuation, taking advantage of the extreme softness of the PDMS membrane. A continuous frequency shift varying from 55.35 to 51 GHz ( ≈8%) has been obtained for a tuning range of H between 200µm and 575µm. In all configurations, the antenna remains matched and its radiation characteristics are very satisfactory
Framing the alcohol policy debate: industry actors and the regulation of the UK beverage alcohol market
The equilibrium distribution of magnetization and the processes of magnetization reversal in magnetoelastic nanostructures
International audienc
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