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Satiramatekul T.,Kasetsart University | Bouillault F.,CNRS Electrical Engineering Laboratory of Paris
IEEE Transactions on Magnetics | Year: 2010

This paper deals with two-dimensional modeling of a multifilamentary wire composed of two superconducting filaments in a conducting matrix. In order to avoid three-dimensional problem solving, a novel technique is proposed to solve the coupled problem in two dimensions. For that, it is enough to divide the filaments in several sections in the direction of the length of the wire and to impose a relation between the currents crossing the matrix and the electric fields in the different sections of the filaments. The numerical simulation results show the distributions of the current density in the modeled domain. The influence of the wire length on the total magnetization is also considered. © 2006 IEEE.

Cho J.,Ecole Polytechnique - Palaiseau | Cho J.,KCC Corporation | O'Donnell B.,Ecole Polytechnique - Palaiseau | O'Donnell B.,Total S.A. | And 5 more authors.
Progress in Photovoltaics: Research and Applications | Year: 2013

We present a single pump-down process to texture hydrogenated amorphous silicon solar cells. Mats of p-type crystalline silicon nanowires were grown to lengths of 1 μm on glass covered with flat ZnO using a plasma-assisted Sn-catalyzed vapor-liquid-solid process. The nanowires were covered with conformal layers of intrinsic and n-type hydrogenated amorphous silicon and a sputtered layer of indium tin oxide. Each cell connects in excess of 10 7 radial junctions over areas of 0.126 cmÂ. Devices reach open-circuit voltages of 0.8 V and short-circuit current densities of 12.4 mA cm-2, matching those of hydrogenated amorphous silicon cells deposited on textured substrates. Copyright © 2012 John Wiley & Sons, Ltd.

Longeaud C.,CNRS Electrical Engineering Laboratory of Paris | Schmidt J.A.,CONICET
Journal of Non-Crystalline Solids | Year: 2012

In this paper we review some of the techniques based on the photoconductivity property of hydrogenated amorphous silicon (a-Si:H) from which it is possible to extract transport parameters as well as density of states (DOS) spectroscopies. We also present a new experiment based on the steady state photocarrier grating technique. We show that combined with simple steady state photoconductivity it gives information on the DOS. The comparison of these results with those of other techniques used for DOS measurements theoretically allows determination of transport parameters in a-Si:H. © 2011 Elsevier B.V.

Hubert O.,Ecole Normale Superieure de Cachan | Daniel L.,CNRS Electrical Engineering Laboratory of Paris
Journal of Magnetism and Magnetic Materials | Year: 2011

A main limitation of most models describing the effect of stress on the magnetic behavior is that they are restricted to uniaxial tensile or compressive stress. Nevertheless, stress is multiaxial in most of industrial applications. An idea to overcome the strong limitation of models is to define a fictive uniaxial stress, the equivalent stress, that would change the magnetic behavior in a similar manner than a multiaxial stress. A first definition of equivalent stress, called the deviatoric equivalent stress, is proposed. It is based on an equivalence in magneto-elastic energy. This formulation is first derived for isotropic materials under specific assumptions. An extension to orthotropic media under disoriented magneto-mechanical loading is made. A new equivalent stress expression, called generalized equivalent stress, is then proposed. It is based on an equivalence in magnetization. Inverse identification of equivalent stress is made possible thanks to a strong simplification of the description of the material seen as an assembly of elementary magnetic domains. It is shown that this second proposal is a generalization of the deviatoric expression. Equivalent stress proposals are compared to former proposals and validated using experimental results carried out on an ironcobalt sheet submitted to biaxial mechanical loading. These results are compared to the predictions obtained thanks to the equivalent stress formulations. The generalized equivalent stress is shown to be a tool able to foresee the magnetic behavior of a large panel of materials submitted to multiaxial stress. © 2011 Elsevier B.V. All rights reserved.

Longeaud C.,CNRS Electrical Engineering Laboratory of Paris
Review of Scientific Instruments | Year: 2013

The design of an automated steady state photocarrier grating (SSPG) experiment is presented that matches most of the requirements of an industrial environment. We first briefly recall the bases of the SSPG technique and that the minority carrier diffusion length deduced from this experiment is a key parameter in the fabrication of thin film solar devices. We then underline the main drawbacks of the use of the classical SSPG technique as an industrial and systematic characterization technique mostly that all the adjustments have to be done manually. We show that this issue can be overcome to end with a compact (90 × 60 cm2), fast, reliable, and easy-to-use system that could become a routine characterization technique for research laboratories and thin film solar industry. We illustrate the possibilities of this new system by showing some of the results obtained with it on very different thin films. © 2013 AIP Publishing LLC.

Juillard J.,CNRS Electrical Engineering Laboratory of Paris
Journal of Sound and Vibration | Year: 2015

Abstract In this paper, the equations governing the pull-in of electrostatic (micro-electromechanical systems MEMS) oscillators are established and analyzed. This phenomenon defines the maximal oscillation amplitude that can be obtained without incurring instability and, hence, an upper limit to the performance of a given device. The proposed approach makes it possible to accurately predict pull-in behavior from the purely resonant case, in which the electrostatic bias is very small, to the static case. The method is first exposed in the case of a parallel-plate resonator and the influence of the excitation waveform on the resonant pull-in characteristics is assessed. It is then extended to the more complex case of clamped-clamped and cantilever beams. The results are validated by comparison with transient simulations. © 2015 Elsevier Ltd.

Farouq M.,CNRS Electrical Engineering Laboratory of Paris | Serhir M.,CNRS Electrical Engineering Laboratory of Paris | Picard D.,CNRS Electrical Engineering Laboratory of Paris
Progress In Electromagnetics Research M | Year: 2015

The matrix method for the calculation of antenna far-field using irregularly distributed nearfield measurement data is presented. The matrix method is based on the determination of the plane wave expansion (PWE) coefficients from the irregular near-field samples using a matrix form that connects the radiated field with the corresponding plane wave spectrum. The plane wave spectrum is used to determine the far-field of the antenna under test (AUT). The matrix method has been implemented, and its potentialities are presented. The validations using analytical radiating model (dipoles array) and experimental measurement (X band standard gain horn antenna) results have demonstrated the efficiency and stability of the proposed method. © 2015, Electromagnetics Academy. All rights reserved.

Serhir M.,CNRS Electrical Engineering Laboratory of Paris
Progress In Electromagnetics Research B | Year: 2015

This paper studies the effect of three important parameters in planar time-domain (TD) near-field (NF) to far-field (FF) transformation. These parameters are the NF spatial sampling, NF measurement distance and scan surface truncation. The effect of these parameters over the TD FF accuracy are difficult to predict for Ultra Wide Band antennas. In this paper we aim to choose the optimum NF measurement parameters guaranteeing accurate calculation of the time-domain far-field. This allows the optimization of the computation time and memory requirements. Computations using analytic array of elementary dipoles radiation pattern are used to study the impact of each parameter in time-domain near-field antenna measurement. The comparison of the far-field results are presented in time and frequency domains. In particular, it is shown that the choice of the measurement distance and the size of the scan surface decide predominantly on the frequency band of accurate FF calculation. The used formalism in this paper for the NF to FF transformation is based on the Green's function.

Le T.D.,CNRS Electrical Engineering Laboratory of Paris | Petit M.,CNRS Electrical Engineering Laboratory of Paris
2016 IEEE International Energy Conference, ENERGYCON 2016 | Year: 2016

In this paper, an earth fault location algorithm is developed for distribution networks with resistance-earthed neutral. The algorithm is actually a modified version of Takagi method which was initially applied for HV transmission lines. In the proposed algorithm, fault location is performed by means of a searching process on each homogeneous section of MV lines. The voltage and current information at the beginning of each section, which are needed for the process, will be estimated from measurements at the substation and the network parameters. To improve the accuracy, capacitances of underground cables are also taken into account in the fault distance formula. The simulation results on a CIGRE benchmark network are very encouraging, even with impact of distribution load uncertainty. © 2016 IEEE.

Safour S.,CNRS Electrical Engineering Laboratory of Paris | Bernard Y.,CNRS Electrical Engineering Laboratory of Paris
2016 11th France-Japan and 9th Europe-Asia Congress on Mechatronics, MECATRONICS 2016 / 17th International Conference on Research and Education in Mechatronics, REM 2016 | Year: 2016

The aim of this paper is to investigate the feasibility of a 1D tensile/compression force sensor for mechatronic systems. The main issue to address is the sensing of the static force component, dynamic force sensing is also required. Measurements on a test bench show that for a given vibration mode of the piezoelectric structure, the applied force (stress) has an effect on the material frequency response (electrical admittance). Furthermore, the sensitivity depends on the surrounding materials used in the resonant structure. Key elements are drawn based on the measurements to support modeling and optimal design activities. © 2016 IEEE.

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