Download or read book Etude des interactions entre ondes acoustiques de tr s hautes fr quences dans les cristaux isolants written by Pierre Thery and published by . This book was released on 1969 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Etude des interactions entre ondes lumineuses et ondes acoustiques de haute fr quence dans les cristaux trigonaux written by Edouard Bridoux and published by . This book was released on 1970 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book tude th orique d ondes de volume localis es et de surface dans les cristaux phononiques granulaires written by Hélène Pichard and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ce travail de thèse porte sur l'étude de la propagation d'ondes de volume et d'ondes de surface dans des cristauxphononiques granulaires en régime linéaire. Différents aspects sont développés dans ce manuscrit. L'effet de la prise encompte des degrés de liberté en rotation des particules sur la structure de bande de différents cristaux phononiquesgranulaires est étudié. En effet, l'introduction de ces degrés de liberté additionnels rend possible l'existence de modes derotation qui interagissent fortement avec les modes transverses. Ce travail s'intéresse aussi à l'existence d'ondeslocalisées et d'ondes de surface dans des cristaux phononiques granulaires et en particulier à la comparaison des théoriesdéveloppées avec les prédictions de la théorie de Cosserat. Dans un premier temps, l'étude d'une chaîne phononique granulaire monoatomique est présentée. En considérant lachaîne semi-infinie avec une condition aux limites appliquée à son extrémité, le modèle analytique démontre l'existence demodes localisés, chaque mode étant composé de deux modes évanescents. Ensuite, une description théorique des modes se propageant dans un cristal phononique granulaire en deux dimensions est présentée. Les particules possèdent trois degrés de liberté, deux en translation et un en rotation. L'analyse des interactions entre ondes de translation et ondes de rotation permet de mettre en évidence une grande richesse de structure de bandes ainsi que des phénomènes particuliers (bandes interdites complètes, cône de Dirac, modes non-monotones, phénomène de double réfraction). Dans un dernier temps, une analyse de l'existence d'ondes de Rayleigh et de cisaillement horizontal dans un cristal phononique granulaire en trois dimensions est effectuée. Les limites de la théorie de Cosserat dans la description d'ondes acoustiques de surface dans les milieux micro- et nano-inhomogènes sont établies.
Download or read book Etude des manifestations de l acoustique non lin aire et de ses relations avec les propri t s anharmoniques dans les cristaux isolants written by Bernard Perrin and published by . This book was released on 1978 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Etude th orique et exp rimentale de la propagation acoustique dans les cristaux phononiques granulaires tridimensionnels written by Aurélien Merkel and published by . This book was released on 2010 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: A periodic, ordered and noncohesive structure of monodisperse spherical beads forms a granular phononic crystal. This work is devoted to the propagation of an acoustic wave within this kind of structure. During the propagation of an acoustic wave through a granular crystal, the properties of the phononic crystals (dispersion due to the geometrical periodicity) are combined with the properties of wave propagation in granular media (nonlinearities, rotational degrees of freedom). In this thesis, the dispersion relation of the bulk modes propagating in a hexagonal close-packed structure are theoretically derived. The structure is modeled by a mass-spring structure. The contact interactions between two beads (considered as rigid masses) are modeled by two springs obeying the Hertz-Mindlin theory, with one stiffness for the normal interactions and one for the transverse interactions. In the first part, the spectrum of bulk modes is determined in the case where the transverse interactions are neglected. The dispersion relations of the translational modes propagating within the crystals are derived. In the second part, the transverses rigidities are taken into account. The existence of the transverse interaction associated with the nonzero distance between the centers of the beads and the contact points requires to take into account the rotational degrees of freedom of each individual bead. In the description of continuum elastic media, the rotational degres of freedom are included in the generalized theory of elasticity which is also known as the Cosserat or micropolar theory. Experimental observations in granular materials of the modes predicted by the Cosserat theory (rotational modes and coupled rotational-translational modes) have not been reported before. After the theoretical investigations in a peculiar direction of propagation, the experimental observation of coupled rotational-translational modes in this direction is reported, and constitute a convincing evidence of the phenomena predicted by the Cosserat theory for the granular media. Finally, in this work, we also demonstrated the asymmetry of the classical nonlinear acoustic effect of self-demodulation relative to the direction of the acoustic wave propagation in noncohesive granular crystal under gravity.
Download or read book CONTRIBUTION A L ETUDE DE L INTERACTION ENTRE DES ONDES ACOUSTIQUES ET DES STRUCTURES TOURBILLONNAIRES EMISES PAR UN OBSTACLE PRISMATIQUE DANS UNE CAVITE RECTANGULAIRE written by François Garnier and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: UNE ETUDE EXPERIMENTALE A MONTRE L'EXISTENCE DE NIVEAUX SONORES PLUS INTENSES QUAND LES FREQUENCES D'UN MODE ACOUSTIQUE ET CELLE DE L'EMISSION DE STRUCTURES TOURBILLONNAIRES PAR L'OBSTACLE COINCIDENT. (25) DES VISUALISATIONS ONT MONTRE QUE L'ALLEE TOURBILLONNAIRE EST PLUS SYMETRIQUE EN PRESENCE D'UNE EXCITATION ACOUSTIQUE. (42) UN MODELE ANALYTIQUE FOURNIT DES SPECTRES DE PRESSION ACOUSTIQUE, QUALITATIVEMENT COMPARABLE A L'EXPERIENCE. (58) LA SIMULATION NUMERIQUE, EFFECTUEE EN ADAPTANT LE PROGRAMME KIVA (DEVELOPPE A LOS ALAMOS), PERMET DE RETROUVER LA VALEUR EXPERIMENTALE DU NOMBRE DE STROUHAL ET MONTRE UNE TRANSITION PLUS SOUDAINE, ENTRE UN SILLAGE SYMETRIQUE ET UNE ALLEE TOURBILLONNAIRE, EN PRESENCE D'UNE EXCITATION ACOUSTIQUE. (95) LES RESULTATS OBTENUS POURRAIENT CONDUIRE A TERME A UNE ACTION EFFICACE SUR LES INSTABILITES DE COMBUSTION. (112)
Download or read book Contribution l tude de l interaction entre les ondes acoustiques de surface et les lectrons d un semiconducteur en hyperfr quence written by Van Khiêt Lê and published by . This book was released on 1977 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: ETUDE DE CETTE INTERACTION PAR L'APPLICATION DE LA METHODE DES MODES COUPLES QUI CONSISTE A UTILISER LES FORMULES GENERALISEES DE PIEZOELECTRICITE, D'ELECTROMAGNETISME ET L'EQUATION DES PORTEURS DANS LE SEMICONDUCTEUR. PRINCIPALES THEORIES SUR LE COUPLAGE ENTRE LES ONDES ACOUSTIQUES DE SURFACE ET LES ELECTRONS. APPLICATION DE LA METHODE DES MODES COUPLES A L'ETUDE PROPOSEE. PROBLEMES TECHNOLOGIQUES SUR LA FABRICATION DE L'AMPLIFICATEUR ET ETUDE DE SES CARACTERISTIQUES.
Download or read book Diffusion multiple en fluide visco thermique cas du cristal phononique deux dimensions written by Aroune Duclos and published by . This book was released on 2007 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: Une modélisation précise de la propagation et de l'absorption d'ondes acoustiques dans les matériaux poreux est un enjeu majeur notamment dans la lutte contre les nuisances sonores. Des modèles issus de l"homogénéisation et permettant de décrire le comportement de tels matériaux ont été développés depuis plusieurs années, qui s'intéressent à leur capacité d'absorption résultant d'effets visco-thermiques importants aux grandes longueurs d'onde (fréquences audio). Lorsque les longueurs d'ondes diminuent suffisamment (fréquences ultrasonores), des effets de diffusion multiple, entre la microstructure du matériau et l'onde acoustique le traversant, interviennent. Ces effets, qui ne sont pas considérés par les modèles classiques, ne sont pas faciles à introduire en raison de la complexité géométrique des matériaux poreux (à l'échelle microscopique). Pour cette raison, nous nous sommes limités à considérer un réseau périodique à deux dimensions constitué de cylindres rigides (aluminium) entourés d'un fluide dissipatif (air). Cette géométrie simple, aussi appelée cristal phononique, présente des domaines fréquentiels dans lesquels aucune onde ne peut se propager (bandes interdites). Ce phénomène, connu et largement étudié, résulte d'effets de diffusion multiple (interférences). Les positions et les largeurs des bandes interdites sont prédites par de nombreuses méthodes de calcul tenant compte des effets de diffusion multiple en fluide non dissipatif. Dans ce travail, le problème de l'importance, non négligeable, des effets dissipatifs est soulevé. Des extensions permettant d'intégrer les effets visco-thermiques dans un modèle de diffusion multiple sont proposées. Elles permettent dans un premier temps, de mettre en évidence l'influence de ces effets dissipatifs sur la propagation dans un régime hautes fréquences. Pour cela, une comparaison entre les coefficients de transmission prédits et ceux, obtenus expérimentalement sur différents échantillons est réalisée. Dans un second temps, une étude numérique permet d'analyser la transition entre un domaine fréquentiel dominé par des effets visco-thermiques (exclusivement) et l'émergence des effets de diffusion multiple lorsque la fréquence augmente. Cette analyse montre notamment la limite de validité des modèles classiques issus de la théorie d'homogénéisation, pour la caractérisation acoustique des matériaux poreux.
Download or read book Contribution l analyse spectrale des ondes acoustiques written by Malek Benslama and published by . This book was released on 1992 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS AVONS ETUDIE LA PROPAGATION DES ONDES ACOUSTIQUES DE SURFACE (OAS), DE VOLUME, LES PSEUDO-ONDES DE SURFACE ET LES ONDES DE VOLUME RAMPANTES SOUS LA SURFACE DANS LES MATERIAUX PIEZOELECTRIQUES PAR UNE METHODE D'ANALYSE SPECTRALE. NOUS INTRODUISONS UNE MODIFICATION DANS LA CONDITION DE CONTINUITE DE LA COMPOSANTE NORMALE DE LA CONTRAINTE, EN SUPPOSANT, L'EXISTENCE D'UNE CHARGE Q(X) ) LA SURFACE DU MATERIAU. EN APPLIQUANT LA TRANSFORMEE DE FOURIER NOUS DEDUISONS LES COMPOSANTES DU VECTEUR DEPLACEMENT DE PARTICULE SOUS L'INFLUENCE DE LA CHARGE. NOUS DETERMINONS LES FONCTIONS DE GREEN POUR LE CAS ELECTROSTATIQUE, POUR LES ONDES DE SURFACE ET POUR LES ONDES DE VOLUME. NOUS CONSTATONS DANS L'ANALYSE DU NOYAU G(S) DE LA FONCTION DE GREEN QUE LES POINTS DE BRANCHEMENT CORRESPONDENT DES SSBW. LE PROBLEME DES SINGULARITES RESULTANT DE LA PRESENCE DES SSBW EST RESOLU PAR UNE METHODE DE CALCUL ANALYTIQUE (METHODE DE COL) ET LA METHODE DE LA DESCENTE RAPIDE. LE COUPLAGE D'UNE ONDE ACOUSTIQUE DE SURFACE ET D'UN TRANSDUCTEUR INTERDIGITE DEPOSE SUR LE SUBSTRAT EST ETUDIE. DEUX CAS SONT CONSIDERES: A) TRANSDUCTEUR UNIFORME, B) TRANSDUCTEUR NON-UNIFORME (LARGEUR DES DOIGTS VARIABLE). NOUS UTILISONS LES FONCTIONS DE GREEN POUR CARACTERISER LE COMPORTEMENT DU SYSTEME. EN OUTRE, IL EST TENU COMPTE DANS LE CALCUL DE LA CHARGE DE MASSE DES TRANSDUCTEURS, CE QUI PERMET D'EN MESURER L'INFLUENCE SUR L'IMPEDANCE D'ENTREE. L'INTERACTION ACOUSTOELECTRIQUE ENTRE UN SEMI CONDUCTEUR ET UN PIEZOELECTRIQUE EST ETUDIE
Download or read book Adhesion Between Polymers and Concrete Adh sion Entre Polym res Et B ton written by H. R. Sasse and published by Springer. This book was released on 1986 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preface Adhesion is a phenomenon architects and civil engineers are not very familiar with. In other disciplines knowledge about surface properties and the background of bonding energies is also far from satisfactory; nevertheless there are many important· applications in concrete engineering, where adhesion is necessary for success and durability. These include: - coating and painting - repair of concrete surfaces - bonding of fresh to old concrete - crack injection - glueing of precast elements - glueing of steel to concrete, etc. In 1981 RILEM established the technical committee 52-RAC 'Resin Adherence to Concrete'. The main aims of the committee's work were - to collect research results and practical experiences - to initiate and coordinate research programs - to develop, on a scientific base, test methods for field and for laboratory purposes. One of the results of the committee's work is a state-of-the-art report, which will be presented orally as a General Report at the International Symposium ISAP '86, and will be printed either in the RILEM journal Materials and Structures or separately. Several test recommendations have been elaborated and will be prepared as drafts for the participants ofISAP '86. These are: - direct tensile test - pull-off test - direct shear test - slant shear test - four-point bending test - dynamic loading test - thermal compatibility test (two versions) - injectibility test.
Download or read book Optical Properties Of Graphene written by Rolf Binder and published by World Scientific. This book was released on 2016-11-11 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive state-of-the-art overview of the optical properties of graphene. During the past decade, graphene, the most ideal and thinnest of all two-dimensional materials, has become one of the most widely studied materials. Its unique properties hold great promise to revolutionize many electronic, optical and opto-electronic devices. The book contains an introductory tutorial and 13 chapters written by experts in areas ranging from fundamental quantum mechanical properties to opto-electronic device applications of graphene.
Download or read book A Frequency Dictionary of French written by Deryle Lonsdale and published by Routledge. This book was released on 2009-03-25 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Frequency Dictionary of French is an invaluable tool for all learners of French, providing a list of the 5000 most frequently used words in the language. Based on a 23-million-word corpus of French which includes written and spoken material both from France and overseas, this dictionary provides the user with detailed information for each of the 5000 entries, including English equivalents, a sample sentence, its English translation, usage statistics, and an indication of register variation. Users can access the top 5000 words either through the main frequency listing or through an alphabetical index. Throughout the frequency listing there are thematically-organized lists of the top words from a variety of key topics such as sports, weather, clothing, and family terms. An engaging and highly useful resource, the Frequency Dictionary of French will enable students of all levels to get the most out of their study of French vocabulary. Former CD content is now available to access at www.routledge.com/9780415775311 as support material. Designed for use by corpus and computational linguists it provides the full text in a format that researchers can process and turn into suitable lists for their own research work. Deryle Lonsdale is Associate Professor in the Linguistics and English Language Department at Brigham Young University (Provo, Utah). Yvon Le Bras is Associate Professor of French and Department Chair of the French and Italian Department at Brigham Young University (Provo, Utah).
Download or read book Imaging in Percutaneous Musculoskeletal Interventions written by Afshin Gangi and published by Springer Science & Business Media. This book was released on 2010-06-29 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book details imaging in percutaneous musculoskeletal interventions. It describes in exhaustive detail the abilities and uses of imaging in guiding procedures ranging from biopsy and joint injection to management of pain and tumors. In addition, it documents the different indications for vascular interventions in musculoskeletal lesions and focuses on ultrasound-guided interventions.
Download or read book Therapeutic Ultrasound written by Jean-Michel Escoffre and published by Springer. This book was released on 2015-10-20 with total page 459 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights advances and prospects of a highly versatile and dynamic research field: Therapeutic ultrasound. Leading experts in the field describe a wide range of topics related to the development of therapeutic ultrasound (i.e., high intensity focused ultrasound, microbubble-assisted ultrasound drug delivery, low intensity pulsed ultrasound, ultrasound-sensitive nanocarriers), ranging from the biophysical concepts (i.e., tissue ablation, drug and gene delivery, neuromodulation) to therapeutic applications (i.e., chemotherapy, sonodynamic therapy, sonothrombolysis, immunotherapy, lithotripsy, vaccination). This book is an indispensable source of information for students, researchers and clinicians dealing with non-invasive image-guided ultrasound-based therapeutic interventions in the fields of oncology, neurology, cardiology and nephrology.
Download or read book Experimental Chaos written by Stefano Boccaletti and published by A I P Press. This book was released on 2004-12-14 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 8th Experimental Chaos Conference again demonstrated the broad spectrum of areas where nonlinear dynamics plays an important role, such as circuits, hydrodynamics, optics, chemistry, fracture dynamics, neuroscience, and cognitive science. Additional contributions outline the trends for development and application of concepts and techniques of nonlinear dynamics.
Download or read book Critical Technologies Plan written by and published by . This book was released on 1989 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In Vessel Melt Retention and Ex Vessel Corium Cooling IAEA Tecdoc No 1906 written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2020-08-06 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.
