A method of measuring a thickness of materia material layer threshold purely resistive, implementation of the device and use such a device in an exhaust pot
The invention provides a reliable, simple and accurate for detecting a threshold thickness of a p... more The invention provides a reliable, simple and accurate for detecting a threshold thickness of a purely resistive material, providing a response independent of the resistivity of materiau.L'invention relates to a measuring method, using a sensor comprising at least two pairs of electrodes between which a specified voltage is applied, a width and / or spacing of the first pair of electrodes being such that the electric field lines are predominantly confined within said layer, and a width and / or spacing of the second pair being such that at least part of the electric field lines are outside of said layer when the threshold thickness is reached. Comprising the steps of: - measuring, respectively, a first resistor or intensity and a second resistor or current between the electrodes of the first and second pairs, - compare the second and first resistances or currents, - generating a signal when said resistances or intensities are equal, the widths and / or lengths and / or supply vo...
ABSTRACT The feasibility of planar screen-printed CO2 sensors based on LiSICON as ion conductor a... more ABSTRACT The feasibility of planar screen-printed CO2 sensors based on LiSICON as ion conductor and on lithium carbonate as auxiliary phase is demonstrated, on the condition that the carbonate melts during the manufacturing process. The addition of calcium or barium carbonate to lithium carbonate in eutectic proportions, suppresses the interference with water vapor. The replacement of both carbonate and gold superposed layers by a unique composite layer serving as working electrode, strongly improves the recovery times. The surface ratio between the working and reference electrodes appears of primary importance in the operating of the sensor and a tentative explanation of the phenomenon is proposed. The performances of sensors optimized on the basis of these results are finally evaluated.
Giant electro-mechanical transduction in all-organic MEMS for physical and chemical sensors
2016 IEEE 29th International Conference on Micro Electro Mechanical Systems (MEMS), 2016
This paper reports an organic MEMS sensor with a cutting-edge electro-mechanical transducer based... more This paper reports an organic MEMS sensor with a cutting-edge electro-mechanical transducer based on an active organic field effect transistor (OFET). The strategy lies in the integration of a piezoelectric Poly (VinyliDene Fluoride/TriFluoroEthylene) (P(VDF/TrFE)) copolymer as active gate dielectric layer in an OFET device mounted on a polymer micro-cantilever. The charges generated by the piezoelectric layer due to surface strain are converted and amplified into drain current. Such an advanced scheme enables highly efficient integrated electromechanical transduction with record relative sensitivity ((ΔID/IDS)/ε) over 600 in the low strain regime, constituting a key-step for the development of highly sensitive MEMS sensors.
Ce chapitre traite en premiere partie des capteurs a fibre optique, dans une deuxieme partie des ... more Ce chapitre traite en premiere partie des capteurs a fibre optique, dans une deuxieme partie des capteurs de type "pile a combustible" enfin des capteurs sans couche sensible, exploitant une propriete physique du gaz : capteurs a absorption optique, a photo-ionisation, a conductivite thermique, a vitesse du son et paramagnetique.
Etude et mise au point d'un dispositif experimental de mesure de la vitesse d'un jet de plasma rarefie
La soufflerie sr1 du laboratoire d'aerothermique permet de realiser des jets de plasma rarefi... more La soufflerie sr1 du laboratoire d'aerothermique permet de realiser des jets de plasma rarefies stationnaires a symetrie cylindrique. La mesure de la vitesse s'inscrit dans un programme d'etude et de caracterisation de ces jets. En raison des conditions experimentales, le choix du diagnostic s'est porte sur une methode magnetohydrodynamique (mhd). Cette technique, reposant sur la loi d'ohm generalisee, utilise le champ magnetique cree par des charges en mouvement dans un champ magnetique perpendiculaire a l'ecoulement. Differentes approches theoriques de la loi d'ohm sont presentees et analysees. L'application de cette loi aux mesures de vitesses est discutee en fonction des conditions experimentales. Le dispositif, une fois defini, est experimente dans des jets d'argon, d'azote et d'hydrogene pour differents parametres de fonctionnement. Des profils axiaux et radiaux sont releves. Afin de verifier certaines hypotheses, des mesures complem...
Method for Measuring the Threshold Thickness of a Layer of a Purely Resistive Material, Device for Implementing Same and Use of Said Device in an Exhaust Pipe
The dimensioning and experimental tests of a differential capacitive rain sensor without sensitiv... more The dimensioning and experimental tests of a differential capacitive rain sensor without sensitive layer are presented. The detection principle relies on the change in electric permittivity induced by water on the active area of the sensor. This sensor is made of three protected coplanar electrodes defining two capacitors: a sensitive capacitor which capacitance (C 1 ) varies with water, and an insensitive-reference-capacitor (C 2 ). In dry condition, both capacitances have the same value. Imbalance between C 1 and C 2 reveals the presence of water on the sensor. Two types of electrodes are studied: rectangular and interdigital. The sensors geometrical configurations are first refined by numerical simulation using a finite element method (FEM). The sensors behavior in different rain conditions is then simulated using the same FEM software. Finally, sensors prototypes are manufactured and tested. The rectangular electrodes sensor exhibits a significant sensitivity to water due to both a maximum variation of the sensitive capacitance and a negligible variation of the reference capacitance, while the interdigital electrodes sensor appears to be less sensitive.
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Papers by Pascal Tardy