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Instrument à cordes

Un instrument à cordes est un instrument de musique dans lequel le son est produit par la vibration d'une ou plusieurs cordes. L'organologie les classe dans la catégorie des cordophones. L'histoire des instruments à cordes est vieille de plusieurs milliers d'années. Les premiers n'avaient probablement qu'une seule corde, comme l'arc musical. Dès l'Égypte ancienne, on connaissait les joueurs de harpe. Au Moyen Âge, les ménestriers s'accompagnaient au luth, etc. Principes La vibration de la corde seule est peu audible. Une plaque couplée aux cordes, la table d'harmonie, prélève une partie de l'énergie vibratoire de la corde pour la transmettre à l'air et obtenir un son. La table d'harmonie peut être une peau de tambour, comme dans le banjo ou la kora. La fréquence fondamentale de la vibration dépend des caractéristiques de longueur, de masse et de tension de la corde. Les cordes ont subi de nombreuses évolutions, du fait notamment des techniques disponibles et de critè

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EE-348: Electroacoustics

Ce cours a pour objectif de former les étudiants de section Génie Electrique et Electronique à la conception de systèmes acoustiques, à l'aide d'un formalisme basé sur l'électrotechnique. A la fin du semestre, les étudiants seront capables de dimensionner, entre autres, des filtres acoustiques.

MICRO-530: Nanotechnology

This course gives the basics for understanding nanotechnology from an engineer's perspective: physical background, materials aspects and scaling laws, fabrication and imaging of nanoscale devices.

MSE-636(b): Scanning electron microscopy techniques (b)

This intensive course is intended for researchers who envisage to use scanning electron microscopy techniques for their research or who want to understand how to interpret SEM images and analytical results presented in scientific publications.

Nano-Tera.ch: Information Technology for Health, Environment, and Energy

Giovanni De Micheli, Patrick Mayor, Martin Rajman

Bettering human health care and creating a sustainable environment through monitoring and smart energy usage are primary goals of advanced societies. To this purpose, the Swiss Government, through the State Secretariat for Education, Research, and Innovation has been funding the Nano-Tera.ch program for about nine years with an overall budget of approximately 250 MUSD, half in cash, and half in matching instruments by public research entities. The program aims at establishing embedded/ cyberphysical systems through the synergy of various disciplines within collaborative research projects, the design of applied demonstrators, targeted educational programs, and the transfer of acquired research results to industry and hospitals.

Ieee-Inst Electrical Electronics Engineers Inc2017

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A universal fluid cell for the imaging of biological specimens in the atomic force microscope

Livan Bladimir Alonso Sarduy, Giovanni Dietler, Sandor Kasas, Giovanni Longo, Charles Roduit, Bhaskar Saha

Recently, atomic force microscope (AFM) manufacturers have begun producing instruments specifically designed to image biological specimens. In most instances, they are integrated with an inverted optical microscope, which permits concurrent optical and AFM imaging. An important component of the set-up is the imaging chamber, whose design determines the nature of the experiments that can be conducted. Many different imaging chamber designs are available, usually designed to optimize a single parameter, such as the dimensions of the substrate or the volume of fluid that can be used throughout the experiment. In this report, we present a universal fluid cell, which simultaneously optimizes all of the parameters that are important for the imaging of biological specimens in the AFM. This novel imaging chamber has been successfully tested using mammalian, plant, and microbial cells. Microsc. Res. Tech. 76:357363, 2013. (c) 2013 Wiley Periodicals, Inc.

Wiley-Blackwell2013

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Time-resolved spectrofluorometer for clinical tissue characterization during endoscopy

Hubert van den Bergh, Georges Wagnières

Time-resolved fluorescence spectroscopy has the potential to provide more information for the detection of early cancer than continuous wave spectroscopy. A new optical fiber-based spectrofluorometer for time-resolved fluorescence spectroscopy of biol. tissue during clin. endoscopy is presented. The app. is based on a nitrogen laser pumping a dye laser as excitation source and a streak camera coupled with a spectrograph as time-resolved spectrometer. The excitation and fluorescence light is carried by an optical fiber to the tissue under investigation and back to the detector, resp. This optical fiber can be inserted into the biopsy channel of a conventional endoscope. Hence, the app. can be used to perform in situ tissue characterization during endoscopy. The instrument enables the measurement of the decays of entire fluorescence spectra within 15 s with a dynamic range of the spectro-temporal images of up to three orders of magnitude. Luminescence lifetimes from the sub ns up to the ms range can be measured. Spectral and temporal resoln., sensitivity, and dynamic range of the instrumentation were detd. The accuracy of the app. was checked by the measurement of the fluorescence lifetimes of various fluorophores with known lifetimes. For the first time, two-dimensional time-resolved spectra with sub-ns temporal resoln. of tissue fluorescence of the human bladder, the bronchi, and the esophagus taken during endoscopy are presented as a demonstration of performance of the instrumentation. The excitation wavelengths were 337 nm in the case of the bladder and the esophagus and 480 nm in the case of the bronchi. Lifetime contrasts between normal and neoplastic tissue were found in all three organs. The spectral anal. of the fluorescence decays showed that the fluorescence between 370 and 490 nm, excited at 337 nm, consisted in several overlapping spectra. In the case of the esophagus, the contrast between normal and tumoral tissue was inverse in two different spectral bands proving the importance of the choice of the appropriate spectral range for time-resolved autofluorescence measurements for an optimal contrast. The in vivo fluorescence decay of the photosensitizers 5-aminolevulinic acid hexylester hydrochloride-induced protoporphyrin IX was measured in the human bladder and found to be mono-exponential with a lifetime of 15.9 (+-1.2) ns. An in vivo fluorescence lifetime of 8.5 (+-0.8) ns was found in the case of the photosensitizer 5, 10, 15, 20-tetra(m-hydroxyphenyl)chlorin (mTHPC) in the esophagus.

American Institute of Physics1999

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Instrument de musique

Musique classique

thumb|250px|Une vingtaine de compositeurs de musique classique, parmi les plus importants couvrant la période du .(De gauche à droite, de haut en bas : — Antonio Vivaldi, Jean-Sébastien Bach, Georg Fr

Piano

thumb|Piano à queue français actuel Pleyel thumb|Intérieur d'un piano droit Le piano est un instrument de musique polyphonique, à clavier, de la famille des cordes frappées. Le son est produit lors