École Polytechnique Fédérale de Lausanne
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Intact and deficient feature fusion in schizophrenia
In patients with schizophrenia, early as well as late stages of information processing can be deficient. Therefore, it is important to determine the earliest occurrences of aberrant processing since deficits on these stages may cause abnormal processing on later, e. g. cognitive, levels. In order to investigate this issue in the visual domain, we studied one of the most basic feature integration mechanisms, namely feature fusion. Our results indicate that in schizophrenic patients this integration mechanism is qualitatively intact but reveals quantitative impairments that may influence later processing stages.LPS
Thermoelectrical study of ferromagnetic nanowire structures
The mixed effects of heat and charge transports have been studied at room temperature for NiCu and CoCu multilayers with currents perpendicular to the interfaces as well as Ni and Co homogeneous nanowires. In order to carry out this analysis, magnetothermogalvanic voltage (MTGV) measurements have been performed. The method consists in monitoring an alternating voltage response that arises when an oscillation of the temperature of the nanostructure is applied and a steady current crosses the nanostructure. Different responses were observed for thicknesses of the ferromagnetic layer larger or shorter than the spin diffusion length. Qualitatively different MTGV profiles were also observed for Ni and Co homogeneous nanowires. These results demonstrate the importance of spin relaxation processes produced in ferromagnetic/nonferromagnetic (FM/NF) interfaces as well as in FM layers for the MTGV response. © 2006 American Institute of Physics.LPM
Reflectance and transmittance model for recto-verso halftone prints: spectral predictions with multi-ink halftones
We extend a previously proposed spectral reflectance and transmittance prediction model for recto-verso prints to the case of multi-ink halftones. The model takes into account the multiple reflections and the lateral propagation of light within the paper substrate (optical dot gain) as well as the spreading of the inks according to their superposition conditions (mechanical dot gain). The model accounts for the orientation of the incident and exiting lights when traversing the halftone ink layers, which enables modeling the measuring geometry. The equations for the calibration of the model and for the predictions are presented in detail. Several experiments with inkjet prints show that the multi-ink halftone transmittance model is as accurate as the actually most performing reflectance models for halftone prints.LS
Surface DBD’s and plasma-flow interaction
Surface Dielelectric Barrier Discharges (DBD) are becoming very attractive in the field of flow control technologies for their promising effects on stabilising separating flows, at least at low speeds under the so-called ionic wind effect. Numerous experiments have been performed over the last few years to further study these effects. At high speeds, such as transonic aircraft or internal engine flow speeds, EPFL has performed studies showing a clear effect of the flow on the plasma, and a lesser effect on the flow, when the plasma is created by a surface embedded DBD that is supplied by AC voltage. Whereas using a nano-pulsed DBD, specific effects of flow interaction have been detected. To this end further studies are undertaken at EPFL to understand the characteristics of such plasmas and their modification in flow conditions using both fast-rise pulsed alimented DBD’s and the continuous AC ones. This paper will present these different aspects.LTTCRPPGTTLINSP