Book Description
UNE ETUDE BIBLIOGRAPHIQUE DES TRAVAUX EXPERIMENTAUX ET THEORIQUES SUR LA PROPAGATION DES ONDES ELECTROMAGNETIQUES DANS LES MATERIAUX HETEROGENES EST PRESENTEE. ON MONTRE QU'UNE BONNE COMPREHENSION DES FAITS OBSERVES SE HEURTE A DES DIFFICULTES D'ORDRE TANT EXPERIMENTAL QUE THEORIQUE. UNE ETUDE EXPERIMENTALE DE LA SPECTROSCOPIE, ENTRE 0.3 ET 2M, DE MATERIAUX HETEROGENES MODELES CONSTITUES DE PARTICULES DE NOIR DE CARBONE DANS UNE MATRICE DE KBR A ETE REALISEE. ELLE DEMONTRE QUE LES THEORIES DU MILIEU EFFECTIF RENDENT CORRECTEMENT COMPTE DES RESULTATS OBTENUS LORSQUE LES PARTICULES SONT PETITES DEVANT LA LONGUEUR D'ONDE ET EN CONCENTRATION FAIBLE. AUX CONCENTRATIONS PLUS ELEVEES (1 A 60% EN VOLUME) ON OBSERVE DES COMPORTEMENTS ORIGINAUX QUE CES THEORIES NE PEUVENT EXPLIQUER
Author: Jean Vareille Publisher: ISBN: Category : Languages : fr Pages : 169
Book Description
NOUS AVONS ETUDIE EXPERIMENTALEMENT LA MECANIQUE DE LA DEFORMATION DE DEUX MATERIAUX COMPOSITES ALEATOIRES SOUMIS A DES CONTRAINTES PURES. NOUS NOUS SONNES ATTACHES AU CAS PARTICULIER DES MATERIAUX COMPOSITES FIBRES DE GRAPHITE GEL DE POLYACRYLAMIDE, QUE NOUS SOUMETTIONS A UNE COMPRESSION UNIAXIALE ET DESQUELS NOUS AVONS ETUDIE LE MODULE D'YOUNG EN FONCTION DE LA CONCENTRATION EN FIBRES. CES MATERIAUX PRESENTENT UN EFFET DE SEUIL MECANIQUE QUI SE TRADUIT PAR UNE FORTE DISPERSION DE RESULTATS DANS UNE ZONE ETENDUE DE CONCENTRATION AUTOUR DE LA CONCENTRATION CRITIQUE, ET PAR UNE EVOLUTION RAPIDE DU MODULE D'YOUNG MOYEN. NOUS AVONS TENTE D'INTERPRETER CES RESULTATS A L'AIDE DE LA THEORIE DE LA PERCOLATION ET DE SES NOUVEAUX DEVELOPPEMENTS. CECI NOUS A PERMIS DE COMPRENDRE LES CAUSES DES PHENOMENES OBSERVES, TOUTEFOIS UN DESACCORD SUBSISTE SUR CERTAINS CALCULS QUANTITATIFS
Author: ABDELMJID.. EL GHEMMAZ Publisher: ISBN: Category : Languages : fr Pages : 169
Book Description
CE TRAVAIL A POUR OBJET L'ETUDE DES PROPRIETES OPTIQUES DE L'ETAIN, DU PLOMB ET DE LEUR ALLIAGE. IL SE SITUE DANS LE CADRE DE RECHERCHES SUR LA STRUCTURE ELECTRONIQUE DES METAUX ET ALLIAGES LIQUIDES. NOUS AVONS CHOISI UNE METHODE OPTIQUE, L'ELLIPSOMETRIE, QUI PERMET A PARTIR DE MESURES DES PARAMETRES ELLIPSOMETRIQUES, D'ACCEDER AUX CONSTANTES OPTIQUES, A LA CONSTANTE DIELECTRIQUE ET DONC A LA CONDUCTIVITE OPTIQUE. DANS UNE PREMIERE ETAPE NOUS AVONS MIS AU POINT UN ELLIPSOMETRE SPECTROSCOPIQUE A POLARISEUR TOURNANT. NOUS AVONS CONCU ET REALISE UNE CELLULE DE MESURE ADAPTEE AUX MESURES DES PROPRIETES OPTIQUES DES METAUX LIQUIDES. L'INTERPRETATION THEORIQUE DES RESULTATS EXPERIMENTAUX A ETE FAITE EN EMPLOYANT LA THEORIE DE L'ELECTRON LIBRE DE DRUDE. NOS RESULTATS SUR LE PLOMB SONT EN BON ACCORD AVEC LE MODELE DE DRUDE, PAR CONTRE CEUX SUR L'ETAIN S'ECARTENT DU MODELE THEORIQUE, CET ECART S'EXPLIQUE PAR L'EXISTENCE PROBABLE D'UNE COUCHE D'OXYDE. LES RESULTATS OBTENUS SUR LES ALLIAGES ETAIN-PLOMB, PRESENTENT LE MEME PHENOMENE QUE L'ETAIN PUR, CE QUI EST EN FAVEUR DE LA FORMATION D'UNE COUCHE D'OXYDE AU BOUT DE QUELQUES SECONDES
Author: Doru Constantin Lupascu Publisher: Springer Science & Business Media ISBN: 3662071894 Category : Technology & Engineering Languages : en Pages : 238
Book Description
A major barrier to the introduction of ferroelectric devices into mass markets remains their limited reliability due to fatigue. The underlying physical and chemical mechanisms of this material fatigue phenomenon are extremely complex, and the relevant influences range from single-point defects to macroscopic boundary conditions. This book summarizes the different aspects of fatigue in ferroelectrics. It is primarily concerned with bulk material effects. Mechanical, electrical, and physico-chemical processes are described; reference data are given for different loading regimes and boundary conditions; and various fatigue models are compared. The monograph also demonstrates how the results of acoustic emission and of microscopy studies reveal the microscopic origins of fatigue in ferroelectric devices.
Author: Reinhard Krause-Rehberg Publisher: Springer Science & Business Media ISBN: 9783540643715 Category : Science Languages : en Pages : 408
Book Description
This comprehensive book reports on recent investigations of lattice imperfections in semiconductors by means of positron annihilation. It reviews positron techniques, and describes the application of these techniques to various kinds of defects, such as vacancies, impurity vacancy complexes and dislocations.
Author: OECD Publisher: OECD Publishing ISBN: 9264305912 Category : Languages : en Pages : 132
Book Description
Government at a Glance Southeast Asia 2019 is the first edition in the Government at a Glance series for the region. It provides the latest available data on public administrations in the 10 ASEAN member countries: Brunei Darussalam, Cambodia, Indonesia, Lao People’s Democratic Republic, Malaysia, Myanmar, the Philippines, Singapore, Thailand and Viet Nam.
Author: Agnes Buka Publisher: World Scientific ISBN: 1848167997 Category : Science Languages : en Pages : 299
Book Description
The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.
Author: Frank C. Hawthorne Publisher: Walter de Gruyter GmbH & Co KG ISBN: 1501508970 Category : Science Languages : en Pages : 716
Book Description
Volume 18 of Reviews in Mineralogy provides a general introduction to the use of spectroscopic techniques in Earth Sciences. It gives an Introduction To Spectroscopic Methods and covers Symmetry, Group Theory And Quantum Mechanics; Spectrum-Fitting Methods; Infrared And Raman Spectroscopy; Inelastic Neutron Scattering; Vibrational Spectroscopy Of Hydrous Components; Optical Spectroscopy; Mossbauer Spectroscopy; MAS NMR Spectroscopy Of Minerals And Glasses; NMR Spectroscopy And Dynamic Processes In Mineralogy And Geochemistry; X-Ray Absorption Spectroscopy: Applications In Mineralogy ind Geochemistry; Electron Paramagnetic Resonance; Auger Electron And X-Ray Photelectron Spectroscopies and Luminescence, X-Ray Emission and New Spectroscopies. The authors of this volume presented a short course, entitled "Spectroscopic Methods in Mineralogy and Geology", May 13-15, 1988, in Hunt Valley, Maryland.
Author: Matthias Gross Publisher: Routledge ISBN: 1317964675 Category : Business & Economics Languages : en Pages : 427
Book Description
Once treated as the absence of knowledge, ignorance today has become a highly influential topic in its own right, commanding growing attention across the natural and social sciences where a wide range of scholars have begun to explore the social life and political issues involved in the distribution and strategic use of not knowing. The field is growing fast and this handbook reflects this interdisciplinary field of study by drawing contributions from economics, sociology, history, philosophy, cultural studies, anthropology, feminist studies, and related fields in order to serve as a seminal guide to the political, legal and social uses of ignorance in social and political life. Chapter 33 of this book is freely available as a downloadable Open Access PDF under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 license available here: https://tandfbis.s3-us-west-2.amazonaws.com/rt-files/docs/Open+Access+Chapters/9780415718967_oachapter33.pdf
Author: DIDIER.. ORDIERA
Author: Jean Vareille
Author: ABDELMJID.. EL GHEMMAZ
Author: J. Belle
Author: Doru Constantin Lupascu
Author: Reinhard Krause-Rehberg
Author: OECD
Author: Agnes Buka
Author: Frank C. Hawthorne
Author: Matthias Gross