Download or read book Gaz lectronique bidimensionnel de haute mobilit dans des puits quantiques de CdTe written by Jan Kunc and published by . This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Une étude expérimentale de gaz d'électrons bidimensionnel confinés dans des puits quantiques de CdTe et de CdMnTe est présentée. L'analyse de données est soutenue par des calculs numériques de la structure de bande des états confinés, utilisant l'approximation de densité locale et de fonction enveloppe. Un calcul de type k.p a été utilisé pour justifier l'approximation parabolique appliquée pour les bandes valence. Les échantillons ont été caractérisés par spectroscopie Raman et par spectroscopie d'absorption de la résonance cyclotron infrarouge. Le magnéto-transport à bas champ est dominé par la contribution semi-classique de Drude et révèle trois contributions plus faibles, qui sont la localisation faible, l'interaction électron-électron et les oscillations Shubnikov-De Haas. La contribution des interactions électron-électron est expliquée dans un modèle semi-classique à trajectoire circulaire. La forme des niveaux de Landau, leurs élargissement, les temps de vie transport et quantique de la diffusion et le mécanisme (long-portée) de la diffusion dominant ont été déterminés. Le magnéto-transport sous champs magnétiques intenses révèle la présence d'états Hall quantique fractionnaires dans les niveaux de Landau N=0 et N=1. Nous avons montré, que les états 5/3 et 4/3 étaient complètement polarisés en spin, en accord avec l'approche des fermions composites pour l'effet Hall quantique fractionnaire. La forme de la photoluminescence à champ magnétique nul et son évolution avec la température sont décrites par un modèle analytique simple. La dépendance en champ magnétique et en température de la photoluminescence indique que le gap de spin est amplifié dans les niveaux de landau entièrement occupés. Ces effets multi-corps de l'amplification du gap du spin ont été décrits avec succès par un modèle numérique simple. L'intensité de la photoluminescence a mise en évidence l'importance des processus non-radiatifs pendant la recombinaison, la dégénérescence des niveaux de Landau, leur taux d'occupation, les règles de sélection et l'influence de l'écrantage. Le mécanisme de la relaxation parallèle de spin d'électron et de trou a été identifié et attribué au mécanisme Bir-Aharonov-Pikus, assistée par les phonons acoustiques. Les spectres de photoluminescence d'excitation reflètent la densité des états caractéristique des systèmes bidimensionnels. Les résonances excitoniques, qui sont observées aux bords des sous-bandes électriques inoccupées, illustrent l'importance de l'écrantage et des champs électriques intrinsèques dans les puits asymétriquement dopés.

Download or read book PROPRIETES OPTIQUES DE PUITS QUANTIQUES DE CDTE CONTENANT UN GAZ D ELECTRONS BIDIMENSIONNEL written by STEPHANE.. LOVISA and published by . This book was released on 1998 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES PROPRIETES OPTIQUES ET MAGNETO-OPTIQUES DE PUITS QUANTIQUES DE CDTE CONTENANT UN GAZ D'ELECTRONS BIDIMENSIONNEL ONT ETE ETUDIEES PAR SPECTROSCOPIE D'ABSORPTION ET D'EMISSION, EN FONCTION DE LA CONCENTRATION DES ELECTRONS. UNE PREMIERE ETUDE PAR SPECTROSCOPIE D'EMISSION, EFFECTUEE SUR UNE SERIE D'ECHANTILLONS A DENSITE ELECTRONIQUE FIXE, A MONTRE QUE LA MASSE EFFECTIVE DES ELECTRONS DEPEND FORTEMENT DE LEUR CONCENTRATION. DES CALCULS TENANT COMPTE DES EFFETS A N CORPS EXPLIQUENT BIEN CETTE RENORMALISATION DE MASSE. PAR AILLEURS, DES DISPOSITIFS SCHOTTKY ONT ETE REALISES QUI PERMETTENT DE VARIER CONTINUMENT LA DENSITE DU GAZ D'ELECTRONS DANS UN PUITS QUANTIQUE DE CDTE A L'AIDE D'UNE TENSION INVERSE APPLIQUEE. L'ETUDE DES PROPRIETES DE MAGNETO-ABSORPTION EN FONCTION DE LA DENSITE A MENE A UNE MODELISATION DE LA FORCE D'OSCILLATEUR DE L'EXCITON CHARGE NEGATIVEMENT OU TRION. LES SPECTRES D'ABSORPTION OBTENUS EN CHAMP NUL SUR DES ECHANTILLONS POSSEDANT DES DESORDRES ELECTROSTATIQUES DIFFERENTS ONT MONTRE L'APPARITION DE ZONES ISOLANTES POUR UNE VALEUR DU RAPPORT DE LA DENSITE D'ELECTRONS ET DU PARAMETRE DE DESORDRE EXACTEMENT EGALE A CELLE PREVUE PAR LA THEORIE RECENTE D'EFROS. LA TRANSITION OPTIQUE TEMOIGNANT DE L'APPARITION DE CES ZONES EST ATTRIBUEE A UN TRION A N CORPS.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book Metallic Magnetism written by I. A. Campbell and published by Springer. This book was released on 1987 with total page 252 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book ZnO Thin Films written by Paolo Mele and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Zinc oxide (ZnO) is an n-type semiconductor with versatile applications such as optical devices in ultraviolet region, piezoelectric transducers, transparent electrode for solar cells and gas sensors. This book "ZnO Thin Films: Properties, Performance and Applications" gives a deep insight in the intriguing science of zinc oxide thin films. It is devoted to cover the most recent advances and reviews the state of the art of ZnO thin films applications involving energy harvesting, microelectronics, magnetic devices, photocatalysis, photovoltaics, optics, thermoelectricity, piezoelectricity, electrochemistry, temperature sensing. It serves as a fundamental information source on the techniques and methodologies involved in zinc oxide thin films growth, characterization, post-deposition plasma treatments and device processing. This book will be invaluable to the experts to consolidate their knowledge and provide insight and inspiration to beginners wishing to learn about zinc oxide thin films.

Download or read book Building Wireless Community Networks written by Rob Flickenger and published by "O'Reilly Media, Inc.". This book was released on 2003 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building Wireless Community Networks is about getting people online using wireless network technology. The 802.11b standard (also known as WiFi) makes it possible to network towns, schools, neighborhoods, small business, and almost any kind of organization. All that's required is a willingness to cooperate and share resources. The first edition of this book helped thousands of people engage in community networking activities. At the time, it was impossible to predict how quickly and thoroughly WiFi would penetrate the marketplace. Today, with WiFi-enabled computers almost as common as Ethernet, it makes even more sense to take the next step and network your community using nothing but freely available radio spectrum. This book has showed many people how to make their network available, even from the park bench, how to extend high-speed Internet access into the many areas not served by DSL and cable providers, and how to build working communities and a shared though intangible network. All that's required to create an access point for high-speed Internet connection is a gateway or base station. Once that is set up, any computer with a wireless card can log onto the network and share its resources. Rob Flickenger built such a network in northern California, and continues to participate in network-building efforts. His nuts-and-bolts guide covers: Selecting the appropriate equipment Finding antenna sites, and building and installing antennas Protecting your network from inappropriate access New network monitoring tools and techniques (new) Regulations affecting wireless deployment (new) IP network administration, including DNS and IP Tunneling (new) His expertise, as well as his sense of humor and enthusiasm for the topic, makes Building Wireless Community Networks a very useful and readable book for anyone interested in wireless connectivity.

Download or read book Wireless Hacks written by Rob Flickenger and published by "O'Reilly Media, Inc.". This book was released on 2003 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuing with the successful Hack Series, this title provides real-world working examples of how to make useful things happen with wireless equipment.

Download or read book Physical Properties of Amorphous Materials written by David Adler and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Institute for Amorphous Studies was founded in 1982 as the international center for the investigation of amorphous mate rials. It has since played an important role in promoting the und er standing of disordered matter in general. An Institute lecture series on "Fundamentals of Amorphous Materials and Devices" was held during 1982-83 with distinguished speakers from universities and industry. These events were free and open to the public ,and were attended by many representatives of the scientific community. The lectures themselves were highly successful inasmuch as they provided not only formal instruction but also an opportunity for vigorous and stimulating debate. That last element could not be captured within the pages of a book I but the lectures concentrated on the latest advances in the field I which is why their essential contents are he re reproduced in collective form. Together they constitute an interdisciplinary status report of the field. The speakers brought many different viewpoints and a variety of back ground experiences io bear on the problems involved I but though language and conventions vary I the essential unity of the concerns is very clear I as indeed are the ultimate benefits of the many-sided approach.

Download or read book Unidentified written by Robert Salas and published by Career Press. This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In 1969 the U.S. Air Force issued a statement that read' "No UFO reported, investigated and evaluated by the Air Force was ever an indication of threat to our national security." This statement is patently false. It has been proven untrue by the testimony of many military officers and airmen and documentation of incidents involving UFOs and nuclear weapons, testimonies of which the U.S. Air Force was fully aware. Unidentified details many of these testimonies, some for the first time. As partial justification for its position, the Air Force cites a University of Colorado study that was contracted and paid for by federal funds. Unidentified reveals how this study was actually just another part of the plan to cover up the reality of the UFO phenomenon. For the first time, Unidentified publishes evidence that the investigators for the Colorado study knew about the UFO-related missile shutdown incidents but did not investigate them or include them in their final report.

Download or read book Lost Secrets of the Sacred Ark written by Laurence Gardner and published by HarperCollins UK. This book was released on 2004 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Ark of the Covenant is the source of one of the deepest mysteries of the Western world. Laurence Gardner has accessed Rosicrucian archives to reveal where the Ark is, what it is and how this lost secret of the distant past has led to the phenomenal new science of space-time manipulation.

Download or read book UFOs are Real written by Clifford E. Stone and published by S.P.I. Books. This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Forest Fire Research written by Universidade de Coimbra and published by . This book was released on 2010 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Encounter with Tiber written by Buzz Aldrin and published by Open Road Media. This book was released on 2013-05-28 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: An Apollo 11 astronaut and the Nebula Award–nominated author of Directive 51 present a novel that “conveys the wonder and promise of space” (Publishers Weekly). Born the year of the Moon landing, Chris Terence spends his life fighting to return humanity to that pinnacle. An engineering student with dreams of spaceflight, he finds upon graduation that the United States no longer has need for astronauts. Years of bureaucratic meddling have reduced the space program to a shell of itself, and it will take the greatest scientific find in history to send humanity skyward once more. After years battling budget hawks, Chris finally gets his chance to walk on the Moon. While there, he finds evidence of an ancient alien civilization, the Tiberians, who visited Earth’s satellite eight thousand years before. Understanding what happened to those long-forgotten travelers will define the lives of Chris and his son, as they fight against all odds to unlock the secrets of the universe. “The collaboration of the first man to pilot a moon lander (Aldrin) with a major voice in contemporary science fiction (Barnes) has produced a fascinating chronicle of man’s first encounter with alien intelligence” (Booklist).