Joint inversion of satellite-detected tidal and magnetospheric signals constrains electrical conductivity and water content of the upper mantle and transition zone

We present a new global electrical conductivity model of Earths mantle. The model was derived by using a novel methodology, which is based on inverting satellite magnetic field measurements from different sources simultaneously. Specifically, we estimated responses of magnetospheric origin and ocean tidal magnetic signals from the most recent Swarm and CHAMP data. The challenging task of properly accounting for the ocean effect in the data was addressed through full three-dimensional solution of Maxwell's equations. We show that simultaneous inversion of magnetospheric and tidal magnetic signals results in a model with much improved resolution. Comparison with laboratory-based conductivity profiles shows that obtained models are compatible with a pyrolytic composition and a water content of 0.01 wt and 0.1 wt in the upper mantle and transition zone, respectively

Method of adjusting the resonance frequency of a micro-machined element

B7:C7:A5:80:3D:8B:A3:98:FC:42:31:31:A4:AB:45:07:F1:0D:CD:E8La présente invention concerne les éléments vibrants micro-usinés se trouvant dans certains composants électromécaniques tels que les résonateurs, les capteurs de mouvement (accéléromètres, gyromètres, ?) et les capteurs de vibrations. La présente invention s'applique notamment à la fabrication de tels composants. Procédé d'ajustement de la fréquence de résonance d'un élément vibrant, comprenant une étape de mesure de la fréquence de résonance (FR) de l'élément vibrant, caractérisé en ce qu'il comprend des étapes consistant à déterminer à l'aide d'abaques, et en fonction de la fréquence de résonance mesurée (FR), des dimensions et une position d'au moins une zone d'épaisseur modifiée à former sur l'élément vibrant pour que la fréquence de résonance de celui-ci corresponde à une fréquence de consigne, et à former sur l'élément vibrant une zone d'épaisseur modifiée aux dimensions et positions déterminées

Numerical and analytical modelling of holed MEMS resonators

International audienceAfter consistently progress in Micro-Electro-Mechanical (MEM) resonators, Silicon oscillators are finally being commercialized for time and frequency control applications not requiring huge frequency accuracy. Indeed, they offer size reduction, potentially low cost and CMOS integration. However, frequency shift because of holes, unavoidable for MEMS release or damping effects, is still one of the challenges to address high frequency accuracy applications. In this article, we present the mechanical modelling of holed clamped-clamped (CC) beam resonators. An analytical and a numerical model have been developed to obtain the frequency variations due to holes onto resonant structures. We note a good agreement between both models, presenting less than 1.5% of deviation. We also report the manufacturing of holed clamped-clamped beam resonators in only six major steps using compatible CMOS process. Electrical tests have been performed to check the functionality of our structures. Finally, electrical measurements and analytical model have been compared and a discrepancy less than 0.4% is reported. Analytical models validation enables designers to benefit from a powerful vibrating MEMS design tool, including the influence of holes onto resonant structures for any kinds of applications from sensors to actuators and oscillators

Compensation de la fréquence des résonateurs MEMS par ajustement in-line

Communication par affich

Modeling, Design, and Manufacturing of Microfabricated Coils With High Inductance Density

This paper addresses the design and manufacturing of small scale square planar coils with inductance densities ranging from 2 to 19 miH.mm-2. The design strategy is based on both analytic formulas and finite element method (FEM). Two different manufacturing techniques, based on copper and aluminum respectively, are used for the coils fabrication and the key aspects as well as the technological limits of each process are discussed. The inductance measurements performed on the completed coils show good agreement with the theoretical predictions, with typical discrepancy below 4%. Finally, the overall performances of the components are evaluated in terms of volumic inductance density and inductance to resistance ratio

Urine-Contactless Device to Empty Bladders: an Ex-Vivo Proof-of-Concept Study in Porcine Bladders

Current treatments for underactive bladder (UAB) have negative side effects, such as urinary tract infections, mainly because devices used for bladder emptying are in direct contact with urine (e.g. permanent or intermittent catheterisation). Moreover, most of the current solutions are invasive [1]. In the present study, we are evaluating the feasibility of a new approach to help empty the bladder, consisting of a non-invasive, urine-contactless device. If this proves to be successful, it could improve the quality of life in patients suffering from UAB. This system is based on the impedance pump principle. An impedance pump is a valve-less pump which is able to drive flow by means of an impedance mismatch: travelling waves are generated by compressing an elastic tube at a specific frequency and location. Reflections of the waves at the points of impedance mismatch create a complex pattern of nonlinear wave interference. The result of these wave-interactions can be a directed flow [2]. This study tests the hypotheses that an impedance pump externally compressing a porcine urethra is able to: i) increase the urinary flow and ii) lead to complete bladder emptying

Holed MEM Resonators with High Aspect Ratio, for High Accuracy Frequency Trimming

International audienceThis paper deals with a new compensation method to insure Micro-Electro-Mechanical (MEM) resonators frequency accuracy. We report new results of modeling, fabrication and characterization of MEM resonators frequency compensated fulfilling industry requirements respect to CMOS compatibility and collective correction. Both clamped-clamped beam and bulk mode resonators presenting compensation holes are treated

MEMS resonator frequency compensation by “in-line” trimming”

International audienceIn this paper, compensation of frequency shifting of MEMS resonators using an end-of-line process step is presented. The technique involves measuring the frequency during manufacturing steps before altering it by added material. An analytical model was developed and compared with finite element simulations (FEM) to highlight the potential of this technique. In parallel, prototypes are being developed to confirm these results experimentally