École Polytechnique Fédérale de Lausanne
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SU-8 nanocomposite coatings with improved tribological performance for MEMS
No full textThe increasing interests in micro-electro-mechanical systems (MEMS) has raised the requirement for photoresist materials with improved friction and wear properties for mechanically loaded 3D shaped microstructures. In this work, SU8 photoresist layers reinforced with different amounts of silica nanoparticles were produced and thermally treated. Dry sliding tests indicate that SU8 composite epoxies produced in the form of thin films exhibit similar or even better tribological properties than bulk epoxies. The SU8 nanocomposites exhibit reduced wear rates and frictional coefficient compared to the un-reinforced material. Further, nanoparticle content, heat treatment and nature of the sliding counter piece were found to affect wear and friction. The tribological behaviour was discussed in terms of mechanical properties and contact pressures.LMIS
The EGNOS Integrity Concept: Evaluation of the Ionospheric Corrections
Get PDFWithin the validation work of EGNOS for civil aviation, it is interesting to analyze the transmitted corrections individually. In this paper, the ionospheric model of EGNOS is compared to the one determined by an independent organization (CODE). The continuous monitoring of the ionosphere is envisaged in order to analyze the ionospheric corrections in real-time. Two methods based on dual-frequency GPS measurements are described. The first approach computes the ionospheric delays after calibration of the receiver DCB (Differential Code Bias) using phase-smoothed code measurements. The second method is based on spherical harmonic expansions.TOP
Architectural Exploration of MPSoC Designs Based on an FPGA Emulation Framework
Get PDFWith the growing complexity in consumer embedded products and the improvements in process technology, Multi-Processor System-On-Chip (MPSoC) architectures have become widespread. These new systems are very complex to design as they must execute multiple complex real-time applications (e.g. video processing, or videogames), while meeting several additional design constraints (e.g. energy consumption or time-to-market). Thus, in order to explore all the possible HW-SW configurations in a MPSoC, simulation is not practical anymore due to the large overhead in time of cycle-accurate simulators, which is the desired level for the extraction of statistics. New methods to extract such fine-grained statistics in a faster way are needed. In this paper, we present a new FPGA-based emulation framework that allows designers to rapidly explore a large range of MPSoC design alternatives at the cycle-accurate level. Our experimients using this platform yield a speed-up of three orders of magnitud compared to cycle-accurate MPSoC simulators, while achieving the same level of accuracy as cycle-accurate MPSoC simulation frameworks.LSI1ES
Structure and Fermi surface mapping of a modulation-free Pb-Bi-Sr-Ca-Cu-O high-temperature superconductor
No full textCIM
3D-ITIES supported on porous reticulated vitreous carbon
No full textA thin aqueous film prepared by layer-by-layer assembly of oppositely charged polypeptides on 4-aminobenzoic acid modified porous reticulated vitreous carbon (RVC) electrodes was used with the aim of forming a 3D-ITIES. The film containing a redox mediator, namely ferri/ferrocyanide, was placed in contact with an organic solution 1,2-dichloroethane containing an electron acceptor, 7,70,8,80-tetracyanoquinodimethane (TCNQ). The reduction of TCNQ was studied to characterise the electrochemical properties of the supported ITIES. When the film is dye-sensitised, a reduction photocurrent was observed upon illumination. This photocurrent was an order of magnitude larger than that measured on a planar electrode.LEP
