Download or read book Diffraction par des surfaces periodiques resolution en coordonnees non orthogonales written by Gérard Granet and published by . This book was released on 1992 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Diffraction par des surfaces rugueuses written by Kofi Sényo Edee and published by . This book was released on 2003 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nous présentons un modèle théorique et numérique pour simuler la diffraction d'ondes électromagnétiques par des surfaces rugueuses monodimensionnelles et non périodiques. La méthode d'étude consiste à écrire et à résoudre les équations de Maxwell en coordonnées de translation afin de faciliter l'écriture des conditions aux limites. Dans un premier chapitre, la méthode est appliquée à l'étude théorique de la diffraction d'une onde plane par un plan localement déformé diélectrique ou conducteur. Les équations de Maxwell, écrite dans le système de coordonnées de translation sont résolues dans l'espace de Fourier par une méthode des moments avec comme fonctions de base des sinus cardinaux et des distributions de Dirac pour fonction test. On obtient une équation aux valeurs propres et les solutions propres servent à la représentation du champ. Dans le second chapitre, une étude numérique est développée, afin de cerner les limites de la méthode. Premièrement, une étude numérique de la stabilité et de la convergence de la méthode en fonction des différents paramètres est effectuée. Deuxièmement, une réflexion sur la représentation du champ lointain et proche conduit à coupler le modèle avec le théorème d'extinction. Le phénomème de faible couplage en champs lointain est abordé à la fin de ce chapitre, dans le but d'étendre le modèle à des surfaces de grande étendue spatiale. Le troisième et dernier chapitre présente une extension du modèle au cas de l'incidence conique et d'un faisceau d'ondes planes. Les applications numériques sont effecutuées sur des surfaces rugueuses aléatoires suivant une statistique Gaussienne
Download or read book CONTRIBUTION A L ETUDE DE LA DIFFRACTION EN COORDONNEES NON ORTHOGONALES written by Brahim Guizal and published by . This book was released on 1998 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS TRAITONS LE PROBLEME DE LA DIFFRACTION D'UNE ONDE ELECTROMAGNETIQUE PAR UNE SURFACE RUGUEUSE, PERIODIQUE OU APERIODIQUE, EN UTILISANT UN SYSTEME COORDONNEES NON ORTHOGONALES. AVEC CE FORMALISME L'ECRITURE DES CONDITIONS AUX LIMITES SE TROUVE GRANDEMENT FACILITEE PAR LE CHOIX D'UN SYSTEME DE COORDONNEES TEL QUE L'UNE DES SURFACES DE COORDONNEES COINCIDE AVEC LA SURFACE DIFFRACTANTE. APPLIQUEE AUX RESEAUX DE DIFFRACTION, ET CONNUE SOUS LE NOM DE : METHODE C, CETTE APPROCHE EST TRES EFFICACE POUR DES RESEAUX A PROFILS LISSES. CEPENDANT ELLE SOUFFRE D'UNE LIMITATION IMPORTANTE : ELLE NE PERMET PAS DE TRAITER LES RESEAUX A PROFILS TRES PENTUS. LE TRAVAIL PRESENTE ICI ETEND LE DOMAINE DE VALIDITE DE LA METHODE DE FACON A CE QU'ELLE PUISSE TRAITER DE NOUVELLES VARIETES DE PROFILS ET PRENDRE EN COMPTE D'AUTRES FORMES D'EXCITATIONS TEL QU'UN FAISCEAU GAUSSIEN ECLAIRANT UNE SURFACE D'EXTENSION FINIE PAR EXEMPLE. DES APPLICATIONS NUMERIQUES SONT PROPOSEES DANS LE CAS DE RESEAUX ECHELETTE UTILISES EN SPECTROSCOPIE ET AYANT UN TRES FAIBLE ANGLE DE BLASE.
Download or read book Diffraction d ondes lectromagn tiques par des surfaces rugueuses al atoires written by Céline Baudier and published by . This book was released on 2002 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans le cadre de la télédétection hyperfréquence, nous cherchons à modéliser l'interaction d'ondes électromagnétiques avec des surfaces rugueuses, soit le phénomène de diffraction. La surface est aléatoire afin de modéliser une surface naturelle telle qu'une parcelle agricole. Nous présentons deux méthodes de calcul de diffraction. La première est une méthode approchée de Rayleigh dont nous cernons le domaine d'application à l'aide de tests de convergence et de critères physiques. La seconde, appelée méthode C, est un formalisme exact basé sur l'écriture des équations de Maxwell dans un système de coordonnées curvilignes lié à la surface. Nous la validons en la confrontant à d'autres méthodes. Nous soulignons dans le même temps l'effet de la rugosité de la surface sur les diagrammes de diffraction, comme le phénomène de rétrodiffusion exaltée. De plus, des comparaisons concluantes sont effectuées avec des mesures expérimentales dans le domaine des fréquences optiques et radar.
Download or read book LA METHODE DES DIFFERENCES FINIES EN COORDONNEES NON ORTHOGONALE written by Olivier Fontaine and published by . This book was released on 1997 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: LE SYSTEME DE COORDONNEES CARTESIENNES UTILISE HABITUELLEMENT DANS LA METHODE DES DIFFERENCES FINIES OBLIGE A REPRESENTER LES CONTOURS COURBES DES STRUCTURES ETUDIEES PAR DES MARCHES D'ESCALIER. LES CONDITIONS AUX LIMITES SONT ALORS APPLIQUEES DE MANIERE APPROXIMATIVE. UNE FORMULATION DE LA METHODE DANS UN SYSTEME DE COORDONNEES NON-ORTHOGONALES ADAPTE A LA FORME DES GEOMETRIES CONSIDEREES EST DEVELOPPEE ICI. CETTE APPROCHE ASSOCIE LE FORMALISME TENSORIEL AVEC LA PROCEDURE CLASSIQUE DES DIFFERENCES FINIES. LE MAILLAGE, COINCIDANT AVEC LES CONTOURS DES STRUCTURES, PERMET UNE APPLICATION PLUS RIGOUREUSE DES CONDITIONS AUX LIMITES, ET CE INDEPENDAMMENT DE LA TAILLE DES MAILLES. LA METHODE EST APPLIQUEE A DEUX PROBLEMES DE L'ELECTROMAGNETISME : UN PROBLEME OUVERT DE DIFFRACTION (RESOLUTION DES EQUATIONS DE MAXWELL DANS LE DOMAINE TEMPOREL) ET UN PROBLEME BORNE DE GUIDE (RESOLUTION DANS LE DOMAINE FREQUENTIEL DES EQUATIONS DE PROPAGATION). L'APPLICATION AUX PROBLEMES DE DIFFRACTION CONSISTE A ETUDIER DANS LE DOMAINE TEMPOREL, LE COUPLAGE D'UNE IMPULSION ELECTROMAGNETIQUE AVEC UNE STRUCTURE 2D. L'ETUDE DES PROBLEMES DE GUIDE EST QUANT A ELLE BASEE SUR LA CARACTERISATION PAR MATRICE S D'UNE STRUCTURE DE GUIDE RECTANGULAIRE A FACES METALLIQUES NON PARALLELES. CES ETUDES ONT ETE VALIDEES EN COMPARANT, DANS LE CAS DE LA DIFFRACTION, LES FORMULATIONS CARTESIENNES ET NON-ORTHOGONALES DE LA METHODE ET EN VERIFIANT, POUR LE PROBLEME DE GUIDE, LE CRITERE DE RECIPROCITE ET LA CONSERVATION DE L'ENERGIE.
Download or read book Crystallography of Quasicrystals written by Steurer Walter and published by Springer Science & Business Media. This book was released on 2009-08-26 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: From tilings to quasicrystal structures and from surfaces to the n-dimensional approach, this book gives a full, self-contained in-depth description of the crystallography of quasicrystals. It aims not only at conveying the concepts and a precise picture of the structures of quasicrystals, but it also enables the interested reader to enter the field of quasicrystal structure analysis. Going beyond metallic quasicrystals, it also describes the new, dynamically growing field of photonic quasicrystals. The readership will be graduate students and researchers in crystallography, solid-state physics, materials science, solid- state chemistry and applied mathematics.
Download or read book Gratings Theory and Numeric Applications written by and published by Popov, Institut Fresnel. This book was released on with total page 431 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Foundations of Antenna Engineering A Unified Approach for Line of Sight and Multipath written by Per-Simon Kildal and published by Artech House. This book was released on 2015-06-01 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first textbook that contains a holistic treatment of antennas both for traditional antennas mounted on masts (Line-of-Sight antenna systems) and for small antennas used on modern wireless devices such as smart phones being subject to signal variations (fading) due to multipath propagation. The focus is on characterization, as well as describing classical antennas by modern complex vector theory - thereby linking together many disciplines such as electromagnetic theory, classical antenna theory, wave propagation, and antenna system performance. Overall, this book represents a rethinking of the way basic antenna theory is presented. The book contains many references to important old and new papers and books on the analysis and design of the most useful antenna types, for the most interested readers.
Download or read book The Language of Physics written by Elizabeth Garber and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is the first explicit examination of the key role that mathematics has played in the development of theoretical physics and will undoubtedly challenge the more conventional accounts of its historical development. Although mathematics has long been regarded as the "language" of physics, the connections between these independent disciplines have been far more complex and intimate than previous narratives have shown. The author convincingly demonstrates that practices, methods, and language shaped the development of the field, and are a key to understanding the mergence of the modern academic discipline. Mathematicians and physicists, as well as historians of both disciplines, will find this provocative work of great interest.
Download or read book Introduction to Nanophotonics written by Sergey V. Gaponenko and published by Cambridge University Press. This book was released on 2010-04-08 with total page 485 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanophotonics is where photonics merges with nanoscience and nanotechnology, and where spatial confinement considerably modifies light propagation and light-matter interaction. Describing the basic phenomena, principles, experimental advances and potential impact of nanophotonics, this graduate-level textbook is ideal for students in physics, optical and electronic engineering and materials science. The textbook highlights practical issues, material properties and device feasibility, and includes the basic optical properties of metals, semiconductors and dielectrics. Mathematics is kept to a minimum and theoretical issues are reduced to a conceptual level. Each chapter ends in problems so readers can monitor their understanding of the material presented. The introductory quantum theory of solids and size effects in semiconductors are considered to give a parallel discussion of wave optics and wave mechanics of nanostructures. The physical and historical interplay of wave optics and quantum mechanics is traced. Nanoplasmonics, an essential part of modern photonics, is also included.
Download or read book Billiards written by Serge Tabachnikov and published by SMF. This book was released on 1995 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Italian Mathematics Between the Two World Wars written by Angelo Guerraggio and published by Springer Science & Business Media. This book was released on 2005-11-17 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes Italian mathematics in the period between the two World Wars. It analyzes the development by focusing on both the interior and the external influences. Italian mathematics in that period was shaped by a colorful array of strong personalities who concentrated their efforts on a select number of fields and won international recognition and respect in an incredibly short time. Consequently, Italy was considered a third mathematical power after France and Germany.
Download or read book Spin Waves written by Daniel D. Stancil and published by Springer Science & Business Media. This book was released on 2009-04-05 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book begins by introducing magnetism and discusses magnetic properties of materials, magnetic moments of atoms and ions, and the elements important to magnetism. It covers magnetic susceptibilities and electromagnetic waves in anisotropic dispersive media among other topics. There are problems at the end of each chapter, many of which serve to expand or explain the material in the text. The bibliographies for each chapter give an entry to the research literature.
Download or read book Spectral Geometry written by Pierre H. Berard and published by Springer. This book was released on 2006-11-14 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vibration Engineering and Technology of Machinery written by José Manoel Balthazar and published by Springer Nature. This book was released on 2021-03-03 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume gathers the latest advances, innovations and applications in the field of vibration and technology of machinery, as presented by leading international researchers and engineers at the XV International Conference on Vibration Engineering and Technology of Machinery (VETOMAC), held in Curitiba, Brazil on November 10-15, 2019. Topics include concepts and methods in dynamics, dynamics of mechanical and structural systems, dynamics and control, condition monitoring, machinery and structural dynamics, rotor dynamics, experimental techniques, finite element model updating, industrial case studies, vibration control and energy harvesting, and MEMS. The contributions, which were selected through a rigorous international peer-review process, share exciting ideas that will spur novel research directions and foster new multidisciplinary collaborations.
Download or read book Mathematical Analysis of Evolution Information and Complexity written by Wolfgang Arendt and published by John Wiley & Sons. This book was released on 2009-07-10 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical Analysis of Evolution, Information, and Complexity deals with the analysis of evolution, information and complexity. The time evolution of systems or processes is a central question in science, this text covers a broad range of problems including diffusion processes, neuronal networks, quantum theory and cosmology. Bringing together a wide collection of research in mathematics, information theory, physics and other scientific and technical areas, this new title offers elementary and thus easily accessible introductions to the various fields of research addressed in the book.
Download or read book Acoustical Analysis of the Tanpura written by Asoke Kumar Datta and published by Springer. This book was released on 2018-10-01 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses the acoustic signal analysis and spectral dynamics of the tanpura, an Indian plucked string instrument. In addition, it strives to provide a logical and objective explanation of Indian classical musicians’ cognitive experience. Issues of relevance in this regard include the rich, mellifluous sound; the undulation of the loudness; the somewhat cyclical variation of the timbre, which is strongly related to these undulations; and the occasional perception of virtual notes to which no strings are tuned. The book analyses the materials used in the tanpura, the instrument’s simple structure, the intricacies of the lower bridge, and the theory of string vibration with variable string length. Cognitive experiments to provide the basis for perceptual quality assessment, as well as a methodology for ranking, are described. This is followed by acoustic analyses, both temporal and spectral, for sounds produced by male and female tanpuras, for each individual string and the combined one. An important aspect related to the naturalness of perceived sound, namely the intrinsically associated random perturbations, is also discussed. The apparent irregularities perceived in the acoustic signal produced by the tanpura reveal the importance of examining the signal from the perspective of non-linear analysis, an aspect that is also covered in the book. Given its scope, the book will appeal to students and researchers in the fields of music acoustics, artificial intelligence, and cognitive science, as well as musicians and musicologists around the world.
