Piezoelectric and optical setup to measure an electrical field: Application to the longitudinal near-field generated by a tapered coax

We propose a new setup to measure an electrical field in one direction. This setup is made of a piezoelectric sintered lead zinconate titanate film and an optical interferometric probe. We used this setup to investigate how the shape of the extremity of a coaxial cable influences the longitudinal electrical near-field generated by it. For this application, we designed our setup to have a spatial resolution of 100 um in the direction of the electrical field. Simulations and experiments are presented

Longitudinal Electrical Near-field generated by a Tapered Coax and studied with a Piezoelectric Film coupled with an Optical Probe

International audienceWe investigated the influence of using a conical end on the longitudinal electrical near-field generated by a coaxial cable. Simulations with Finite Integration Technique show that this influence greatly varies along the longitudinal axis. Experimental measurements were also carried out. To that purpose, we designed a new set-up to measure the electrical field in one direction with a spatial resolution of 100 microns in this direction, with nearly no perturbation by the other components of the field. This set-up uses a piezoelectric sintered PZT film and a heterodyne laser probe

Simultaneous measurement of Young's modulus and Poisson's ratio at microscale with two-modes scanning microdeformation microscopy

International audienceIn this paper, we present a technique to simultaneously measure Young's modulus E and Poisson's ratio ν of an isotropic material at local scale in a single experiment. Using several flexural modes of vibration of the scanning microdeformation microscope, it is possible to decouple the contributions of E and ν from the first two resonant frequencies, thereby providing access to both the elastic parameters. The proposed approach is applied to SU8 thin films deposited on silicon substrates and provides values consistent with those from the literature

ULTRA-LOCAL TEMPERATURE MAPPING WITH AN INTRINSIC THERMOCOUPLE

Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920)International audienceWe report on a set-up derived from an Electrostatic Force Microscope (EFM) allowing us to probe temperature with a high spatial resolution. The system uses the well-known Seebeck effect through an intrinsic thermocouple made from an EFM conducting tip put in contact with a conducting sample. The contact radius between tip and sample is currently estimated to be in the 50 to 100 nm range depending on the elastic or the plastic deformation. The contact area can be assimilated to the electrical and thermal contact areas. In those conditions, the issue of heat conduction in air is solved. The thermal measurement is related to the Seebeck junction effect : it will therefore not be sensitive to buried materials or impurities

Mineralization of organic pollutants by anodic oxidation using reactive electrochemical membrane synthesized from carbothermal reduction of TiO2

Reactive Electrochemical Membrane (REM) prepared from carbothermal reduction of TiO2 is used for the mineralization of biorefractory pollutants during filtration operation. The mixture of Ti4O7 and Ti5O9 Magnéli phases ensures the high reactivity of the membrane for organic compound oxidation through •OH mediated oxidation and direct electron transfer. In cross-flow filtration mode, convection-enhanced mass transport of pollutants can be achieved from the high membrane permeability (3300 LMH bar-1). Mineralization efficiency of oxalic acid, paracetamol and phenol was assessed as regards to current density, transmembrane pressure and feed concentration. Unprecedented high removal rates of total organic carbon and mineralization current efficiency were achieved after a single passage through the REM, e.g. 47 g m-2 h-1 - 72% and 6.7 g m-2 h-1 - 47% for oxalic acid and paracetamol, respectively, at 15 mA cm-2. However, two mechanisms have to be considered for optimization of the process. When the TOC flux is too high with respect to the current density, aromatic compounds polymerize in the REM layer where only direct electron transfer occurs. This phenomenon decreases the oxidation efficiency and/or increases REM fouling. Besides, O2 bubbles sweeping at high permeate flux promotes O2 gas generation, with adverse effect on oxidation efficiency

Temperature Measurement of Microsystems by Scanning Thermal Microscopy

Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920)International audienceSurface temperature measurements were performed with a Scanning Thermal Microscope. We aim at proving an eventual sub-micrometric resolution of this metrology when using a wollaston wire probe of micrometric size. A dedicated CMOS device was designed with arrays of lines 0.35mm in size with 0.8 mm and 10mm periods. Integrated Circuits with or without a passivition layer were tested. To enhance sensitivity, the IC heat source was excited with an AC current. We show that the passivation layer spreads heat so that the lines are not distinguishable. Removing this layer allows us to distinguish the lines in the case of the 10mm period

Living without Existing: The Permanent Vegetative State

The situation of persons in a permanent vegetative state, characterized as a state of wakefulness without awareness, raises ethical issues concerning the meaning of a life extended by artificial nutrition and hydration. Incarnating paradoxes which question the boundaries between life and existence, these patients lead us to consider new categories of Being: how do we talk about a ‘non-existent human being’? 要旨 覚醒状態にありながらも意識を持つことができないという特徴をもつ持続的植物状態に陥った人間の状態は、人工的水分栄養補給によって延命することの倫理的な問題を提起する。生きる事と存在する事の境界線を問い直す矛盾を突きつけることで、植物状態の患者は我々に新しい生命の分類について示唆する。「存在しない人間」をどう議論すればよいのだろうか

Components of effective peer helper programs

Peer helper programs have increasingly been implemented in elementary, middle, and high schools, and must be developmentally appropriate for each grade level. Peers can serve as tutors, mentors, mediators, and support systems, and schools utilize peer helper programs in order to assist other students in these areas. Effective peer helper programs share common characteristics. The purpose of this paper is to examine characteristics of effective peer helper programs. These programs incorporate peer helper roles, training considerations, developmental considerations, characteristics of peer helpers, screening and selection procedures, program service and delivery, supervision and evaluation needs, and school/community needs