Search results for "ACOUSTIC"

Regularity of Spike Trains and Harmony Perception in a Model of the Auditory System

2011

Spike train regularity of the noisy neural auditory system model under the influence of two sinusoidal signals with different frequencies is investigated. For the increasing ratio m/n of the input signal frequencies (m, n are natural numbers) the linear growth of the regularity is found at the fixed difference (m - n). It is shown that the spike train regularity in the model is high for harmonious chords of input tones and low for dissonant ones.

Loudness changes induced by a proximal sound: loudness enhancement, loudness recalibration, or both?

2007

The effect of a forward masker on the loudness of a target tone in close temporal proximity was investigated. Loudness matches between a target and a comparison tone at the same frequency were obtained for a wide range of target and masker levels. Contrary to the hypothesis by Scharf, Buus, and Nieder [J. Acoust. Soc. Am. 112, 807-810 (2002)], these matches could not be explained by an effect of the masker on the comparison loudness, which was measured by loudness matches between the comparison and a fourth tone separated in frequency from the comparison and the masker. The data thus demonstrate that a forward masker has an effect on the loudness of a proximal target. The results are compat…

Estimation of the Velocity of Multiple Moving Persons in Non-Stationary Indoor Environments from Received RF Signals

2019

This paper presents a new accurate iterative procedure to estimate the time-variant (TV) velocity, i.e., TV speed, TV vertical angle-of- motion (VAOM), and TV horizontal angle-of-motion (HAOM), of multiple moving objects/persons in three-dimensional (3D) non-stationary indoor propagation environments. The indoor space is assumed to be equipped with a distributed 3x3 multiple-input multiple-output (MIMO) system. The proposed procedure focuses on estimating the TV speed, TV VAOM, and TV HAOM by matching the spectrogram of the complex channel gain of a non- stationary indoor channel model to the spectrogram obtained from received radio frequency (RF) signals. Together with the velocity …

Characterization of materials toward toluene traces detection for air quality monitoring and lung cancer diagnosis

2017

International audience; The aim of this work was to identify a nanoporous material able to trap toluene traces in order to develop a gas detection device for indoor air quality monitoring or biomedical diagnosis. A set of various adsorbents such as zeolites and activated carbon microspheres was studied here. First a detailed characterization of their porous properties was performed by nitrogen adsorption. Then adsorption of toluene and other interfering compounds which can selectively adsorbed with it, such as water and carbon dioxide, was studied in order to select the most suitable material. Results revealed that the activatedcarbon microspheres W5 and the zeolite NaY, which exhibit high …

Preparation of conductive PDDA/(PEDOT:PSS) multilayer thin film: influence of polyelectrolyte solution composition.

2014

Abstract Self-assembled multilayer films made of PEDOT:PSS poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) and PDDA poly(diallyldimethylammonium chloride) were prepared using layer-by-layer method. In order to modify the growth regime of the multilayer, to fabricate an electrical conductive film and to control its thickness, the effects of pH, type of electrolyte, ionic strength and polyelectrolyte concentration were investigated. Optical reflectometry measurements show that the pH of the solutions has no effect on the film growth while the adsorbed amount increases more rapidly when BaCl2 is used instead of NaCl as electrolyte. An increase in the ionic strength (with NaCl) induces…

Structural study of gallium oxynitrides prepared by ammonolysis of different oxide precursors

2009

International audience; A comparative structural study has been carried out on gallium oxynitride powders using XRD and Raman spectroscopy. Gallium oxynitrides have been prepared by ammonolysis of either NiGa2O4 ternary oxide or the citrate method-derived amorphous oxide. Their crystal chemistry is different and appears to be influenced by the nature of the oxide precursor: whereas gallium oxynitride obtained from amorphous gallium oxide crystallizes with the common wurtzite structure, gallium oxynitride obtained from NiGa2O4 crystallizes with an original structure that we have identified as the carborundum II (B6) structure type or 6H-SiC. As far as we know, this is the first 6H-SiC struct…

Influence of pressure on ultrasonic cavitation activity in room temperature ionic liquids: An electrochemical study

2019

Abstract This paper provides proofs of the respective contributions of dissolved gases and solvent vapor on cavitation activity in sonoreactors. This activity can be detected by electrochemistry because the fluctuating events measured at the electrode surface are only linked to physical effects of cavitation. As ionic liquids present very low volatilities, their vaporization is reduced, and cavitation bubbles only depend on the presence of gases. Then, cavitation activity may be trigged by reactor atmosphere control. Applying severe depression within an irradiated ionic liquid medium contributes to removing dissolved gases, thus quenching cavitation activity. A specific sonoelectrochemical …

Irradiation of nuclear materials with laser-plasma filaments produced in air and deuterium by terrawatt (TW) laser pulses

2017

Analysis of the electromagnetic radiation generated by a multipactor discharge occurring within a microwave passive component

2010

International audience; Multipactoring is a non-linear phenomenon that appears in highpower microwave equipments operating under vacuum conditions and causes several undesirable effects. In this manuscript, a theoretical and experimental study of the RF spectrum radiated by a multipactor discharge, occurring within a realistic microwave component based on rectangular waveguides, is reported. The electromagnetic coupling of a multipactor current to the fundamental propagative mode of a uniform waveguide has been analyzed in the context of the microwave network theory. The discharge produced under a single-carrier RF voltage regime has been approached as a shunt current source exciting such a…

Terahertz spectroscopy for all-optical spintronic characterization of the spin-Hall-effect metals Pt, W and Cu80Ir20

2018

Identifying materials with an efficient spin-to-charge conversion is crucial for future spintronic applications. In this respect, the spin Hall effect is a central mechanism as it allows for the interconversion of spin and charge currents. Spintronic material research aims at maximizing its efficiency, quantified by the spin Hall angle and the spin-current relaxation length . We develop an all-optical contact-free method with large sample throughput that allows us to extract and . Employing terahertz spectroscopy and an analytical model, magnetic metallic heterostructures involving Pt, W and Cu80Ir20 are characterized in terms of their optical and spintronic properties. The validity of our …