Download or read book L analyse de Front D onde Appliqu e la M trologie de Surface Optique written by Bharath Reddy Adapa and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synchrotrons use a variety of mirrors for reshaping or redirecting X-ray beams. The mirrors can have lengths up to 1.5 m and surface figure errors below 1 nm. Characterization of these mirrors requires advanced metrology tools. More commonly used instruments are Long Trace Profilers (LTP), Nanometer Optical Component Measuring Machines (NOM), Fizeau interferometers and Micro interferometers. The Stitching Shack-Hartmann wavefront sensor (SHARPeR) is a novel 2D slope measuring instrument developed as an integrated commercial product by Imagine Optic and Q-Sys, and uses subaperture stitching algorithms to measure synchrotron mirrors. This thesis has improved the performance of the SHARPeR installed at ESRF. New measurement techniques have been developed to reduce errors from aberrations of optical elements. The impact of mechanical translation errors and environmental errors such as those from air turbulence and temperature fluctuations upon measurement repeatability and accuracy have been characterized, and consequent improvements have been made to the instrument design. The performance of subaperture stitching algorithms has been explored and an open source stitching software package has been developed with multiple working algorithms. The improved instrument performance has been verified using comparative measurements of various artefact mirrors, and comparing to results obtained from more established metrology instruments such as LTP, Fizeau and Micro-interferometers.
Download or read book Etude d un nouveau concept d analyse de front d onde en plan focal appliqu l optique adaptative en astronomie written by Cédric Plantet and published by . This book was released on 2014 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'avènement des Extremely Large Telescopes (ELT) est imminent. Cette nouvelle génération de télescopes ouvrira la voie vers des observations astronomiques toujours plus fines. Les futurs instruments nécessitent des optiques adaptatives de plus en plus sophistiquées pour corriger les effets de la turbulence et atteindre les performances requises. L'analyse de front d'onde est un élément fondamental de l'optique adaptative. Les analyseurs requièrent un flux relativement élevé pour être efficaces, notamment lors de l'estimation de hauts ordres, qui sont nécessaires pour obtenir une bonne correction. Comme le ciel est pauvre en étoiles brillantes, on utilise souvent des étoiles laser, produites par excitation d'un volume de sodium dans la haute atmosphère. Malheureusement, on ne peut pas estimer correctement un tip/tilt avec ces étoiles artificielles. De plus, le focus mesuré est biaisé à cause de l'instabilité en altitude de la couche de sodium. La mesure de ces trois aberrations doit donc pouvoir être faite sur une étoile naturelle de très faible luminosité. On peut alors se demander quelle stratégie adopter pour l'analyse des bas ordres à faible flux. De manière plus générale, les techniques d'analyse de front d'onde sont en pleine évolution pour répondre aux nouveaux besoins de l'optique adaptative. Il est donc important de comparer les stratégies d'analyse en terme de sensibilité et de dynamique. La thèse s'appuie sur un nouveau concept d'analyseur de surface d'onde : LIFT (LInearized Focal-plane Technique). Cet analyseur permettra d'estimer le tip/tilt et le focus sur une étoile naturelle faible, afin de compléter l'analyse faite sur les étoiles lasers, de façon plus efficace qu'avec les moyens actuels. Le premier but de la thèse est d'optimiser et de valider LIFT expérimentalement. Pour cela, j'ai d'abord étudié les propriétés de convergence de l'algorithme et la propagation du bruit afin de déterminer les paramètres optimaux. J'ai ensuite testé le concept de LIFT en laboratoire sur des phases statiques, puis sur le ciel grâce au système d'optique adaptative du télescope Gemini Sud, GeMS. La linéarité de l'estimation malgré la présence de hauts ordres résiduels, dus à la correction imparfaite de l'optique adaptative, a été validée en boucle ouverte, et nous pouvons maintenant envisager une validation finale en intégrant LIFT dans une boucle fermée. Dans un deuxième temps, j'ai étudié la propagation du bruit dans un analyseur dérivé de LIFT, le Shack-Hartmann LIFTé. Cet analyseur divise la pupille à l'aide de micro-lentilles astigmatiques, et une estimation par LIFT est faite dans chaque sous-pupille. Il permettra une estimation de hauts ordres plus précise qu'avec un Shack-Hartmann classique. Le dernier objectif est de comparer les analyseurs existants, en termes de propagation de bruit, pour l'estimation sur étoile naturelle des bas ordres d'une part, cas d'application de LIFT, et des hauts ordres d'autre part, dans le cas d'une optique adaptative extrême par exemple. Cette étude permet de motiver l'utilisation de LIFT et du Shack-Hartmann LIFTé dans des systèmes d'optique adaptative.
Download or read book Analyse de front d onde pour les optiques adaptatives de nouvelle g n ration written by Magalie Nicolle and published by . This book was released on 2006 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several points restrict the efficiency of the wavefront analysis of actual adaptive optics (AO) systems. The mains ones are the measurement noise and the anisoplanatism. Together, they reduce to a few percents the sky coverage of the instruments assisted by AO. For this reason, rising generation of AO systems aims at the very high performance (implying in particular low measurement noise) and/or the widening of the corrected field. For these wide field AO systems, it is essential to use several directions of analysis. The wavefront analysis problem is then articulated around three items : the available guides stars, the considered wavefront sensing concept and quality of the wavefront sensors measurements. The purpose of this PhD thesis is to study each one of these three aspects. Hence a redefinition of the concept of sky coverage is proposed for wide field AO. The definition suggested here takes into account the number of guide stars and their magnitude, but also the fraction of the scientific field that is really covered, the considered wavefront sensing concept and the expected performance of the instrument. Concerning the wavefront sensing concepts, a comparative study of the Star Oriented and Layer Oriented concepts is presented and an optimization is proposed for each one, leading to very close performance. Finally, a comparison of different wavefront slope estimators is proposed for the Shack-Hartmann wavefront sensor. In particular, a weighted center of gravity estimator is studied, that offers a good robustness to noise and good properties of linearity. This last study is usefull as well for wide field AO as for very high performance AO.
Download or read book Body and Spirit in the Middle Ages written by Gaia Gubbini and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-08-10 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: A crucial question throughout the Middle Ages, the relationship between body and spirit cannot be understood without an interdisciplinary approach – combining literature, philosophy and medicine. Gathering contributions by leading international scholars from these disciplines, the collected volume explores themes such as lovesickness, the five senses, the role of memory and passions, in order to shed new light on the complex nature of the medieval Self.
Download or read book Unravelling the Mystery of the Atomic Nucleus written by Bernard Fernandez and published by Springer Science & Business Media. This book was released on 2012-09-28 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unravelling the Mystery of the Atomic Nucleus is a history of atomic and nuclear physics. It begins in 1896 with the discovery of radioactivity, which leads to the discovery of the nucleus at the center of the atom. It follows the experimental discoveries and the theoretical developments up to the end of the Fifties. Unlike previous books regarding on history of nuclear physics, this book methodically describes how advances in technology enabled physicists to probe the physical properties of nuclei as well as how the physical laws which govern these microscopic systems were progressively discovered. The reader will gain a clear understanding of how theory is inextricably intertwined with the progress of technology. Unravelling the Mystery of the Atomic Nucleus will be of interest to physicists and to historians of physics, as well as those interested development of science.
Download or read book How to Hold a Crocodile written by Diagram Group and published by Firefly Books. This book was released on 2003 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: Explains how to do practical and improbable things, such as how to roast an ox, handle a hamster, photography a fish, play the bagpipes, and vanquish a vampire.].
Download or read book Andy Warhol s Blow Job written by Roy Grundmann and published by Temple University Press. This book was released on 2003 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this ground-breaking and provocative book, Roy Grundmann contends that Andy Warhol's notorious 1964 underground film, Blow Job, serves as rich allegory as well as suggestive metaphor for post-war American society's relation to homosexuality. Arguing that Blow Job epitomizes the highly complex position of gay invisibility and visibility, Grundmann uses the film to explore the mechanisms that constructed pre-Stonewall white gay male identity in popular culture, high art, science, and ethnography. Grundmann draws on discourses of art history, film theory, queer studies, and cultural studies to situate Warhol's work at the nexus of Pop art, portrait painting, avant-garde film, and mainstream cinema. His close textual analysis of the film probes into its ambiguities and the ways in which viewers respond to what is and what is not on screen. Presenting rarely reproduced Warhol art and previously unpublished Ed Wallowitch photographs along with now iconic publicity shots of James Dean, Grundmann establishes Blow Job as a consummate example of Warhol's highly insightful engagement with a broad range of representational codes of gender and sexuality. Roy Grundmann is Assistant Professor of Film Studies at Boston University and a contributing editor of Cineaste.
Download or read book Narratives of fear and safety written by Kaisa Kaukiainen and published by BoD - Books on Demand. This book was released on 2020-09-01 with total page 546 pages. Available in PDF, EPUB and Kindle. Book excerpt: The essays in this edited volume, written in English and French, tackle the intriguing problems of fear and safety by analysing their various meanings and manifestations in literature and other narrative media. The articles bring forth new, cross-cultural interpretations on fear and safety through examining what kinds of genre-specific means of world-making narratives use to express these two affectivities. The articles also show how important it is to study these themes in order to understand challenges in times of global threats, such as the climate crisis. The main themes of the book are approached from various theoretical perspectives as related to their literary and cultural representations. Recent trends in research, such as affect and risk theory, serve as the basis for the discussion. The articles in the volume also draw from disciplines such as gender studies and trauma studies to examine the threats posed by collective fears and aggression on individuals' lives and propose ways of coping with fear. These themes are addressed also in articles analysing new adaptations of old myths that retell stories of the past. Many of the articles in the volume discuss apocalyptic and dystopian narratives that currently permeate the entire cultural landscape. Dystopian narratives do not only deal with future threats, such as totalitarianism, technocracy, or environmental disasters, but also suggest alternative ways of being and new hopes in the form of political resistance.
Download or read book The Theory of Gravity written by Anatoliĭ Alekseevich Logunov and published by . This book was released on 2001 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Quantum Communications and Cryptography written by Alexander V. Sergienko and published by CRC Press. This book was released on 2018-10-03 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: All current methods of secure communication such as public-key cryptography can eventually be broken by faster computing. At the interface of physics and computer science lies a powerful solution for secure communications: quantum cryptography. Because eavesdropping changes the physical nature of the information, users in a quantum exchange can easily detect eavesdroppers. This allows for totally secure random key distribution, a central requirement for use of the one-time pad. Since the one-time pad is theoretically proven to be undecipherable, quantum cryptography is the key to perfect secrecy. Quantum Communications and Cryptography is the first comprehensive review of the past, present, and potential developments in this dynamic field. Leading expert contributors from around the world discuss the scientific foundations, experimental and theoretical developments, and cutting-edge technical and engineering advances in quantum communications and cryptography. The book describes the engineering principles and practical implementations in a real-world metropolitan network as well as physical principles and experimental results of such technologies as entanglement swapping and quantum teleportation. It also offers the first detailed treatment of quantum information processing with continuous variables. Technologies include both free-space and fiber-based communications systems along with the necessary protocols and information processing approaches. Bridging the gap between physics and engineering, Quantum Communications and Cryptography supplies a springboard for further developments and breakthroughs in this rapidly growing area.
Download or read book Before We Visit the Goddess written by Chitra Banerjee Divakaruni and published by Simon and Schuster. This book was released on 2017-04-25 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A new novel from the author of Oleander Girl, a novel in stories, built around crucial moments in the lives of 3 generations of women in an Indian/Indian-American Family"--
Download or read book International Human Rights Law in Africa written by Frans Viljoen and published by OUP Oxford. This book was released on 2012-03-29 with total page 661 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive and analytical overview of human rights law in Africa. It examines the institutions, norms, and processes for human rights realization provided for under the United Nations system, the African Union, and sub-regional economic communitites in Africa, and explores their relationship with the national legal systems of African states. Since the establishment of the African Union in 2001, there has been a proliferation of regional institutions that are relevant to human rights in Africa. These include the Pan African Parliament, the Peace and Security Council, the Economic, Social and Cultural Council and the African Peer Review Mechanism of the New Partnership for Africa's Development. This book discusses the links between these institutions. It further examines the case law stemming from Africa' most important human rights instrument, the African Charter on Human and Peoples Rights, which entered into force on 21 October 1986. This new edition contains a new chapter on the African Children's Rights Committee as well as full coverage of new developments and instruments, such as the Convention on the Rights of Persons with Disabilities, the Convention on Enforced Disappearances, and the African Charter on Democracy, Elections and Governance. Three cross-cutting themes are explored throughout the book: national implementation and enforcement of international human rights law; legal and other forms of integration; and the role of human rights in the eradication of poverty. The book also provides an introduction to the relevant human rights concepts.
Download or read book Historia written by Gianna Pomata and published by MIT Press. This book was released on 2005 with total page 501 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essays examine how the genre of historia reflects connections between the study of nature and the study of culture in early modern scholarly pursuits. The early modern genre of historia connected the study of nature and the study of culture from the early Renaissance to the eighteenth century. The ubiquity of historia as a descriptive method across a variety of disciplines--including natural history, medicine, antiquarianism, and philology--indicates how closely intertwined these scholarly pursuits were in the early modern period. The essays collected in this volume demonstrate that historia can be considered a key epistemic tool of early modern intellectual practices. Focusing on the actual use of historia across disciplines, the essays highlight a distinctive feature of early modern descriptive sciences: the coupling of observational skills with philological learning, empiricism with erudition. Thus the essays bring to light previously unexamined links between the culture of humanism and the scientific revolution. The contributors, from a range of disciplines that echoes the broad scope of early modern historia, examine such topics as the development of a new interest in historical method from the Renaissance artes historicae to the eighteenth-century tension between "history" and "system"; shifts in Aristotelian thought paving the way for revaluation of historia as descriptive knowledge; the rise of the new discipline of natural history; the uses of historia in anatomical and medical investigation and the writing of history by physicians; parallels between the practices of collecting and presenting information in both natural history and antiquarianism; and significant examples of the ease with which early seventeenth-century antiquarian scholars moved from studies of nature to studies of culture.
Download or read book The Romantic Agony written by Mario Praz and published by [London] : Collins. This book was released on 1956 with total page 532 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mario Paz has, in the Romantic Agony, acutely analyzed the effect of the traditions of Byron and De Sade upon poets and painters from 1800 to 1900. It is the analysis of a mood in literature. The mood may ve been transient, but it was widespread, and it was expressed in dreams of "luxurious cruelties," "fatal women," corpse-passions, and the sinful agonies of delight. Professo Praz has described the whole Romantic literature under one of its most characteristic aspects, that of erotic sensibility.
Download or read book The First Three Sections of Newton s Principia written by Isaac Newton and published by . This book was released on 1871 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Esprits modernes written by Vlad Alexandrescu and published by Vlad Alexandrescu. This book was released on 2003 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reading the French Enlightenment written by Julie Candler Hayes and published by Cambridge University Press. This book was released on 1999-07-15 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this 1999 book, Julie Candler Hayes offers an ambitious reinterpretation of a crucial aspect of Enlightenment thought, the rationalizing and classifying impulse. Taking issue both with traditional liberal and contemporary critical accounts of the Enlightenment, she analyses the writings of Denis Diderot, Emilie Du Châtelet, the Abbé de Condillac, Buffon, d'Alembert and numerous others, to argue for a new understanding of 'systematic reason' as complex, paradoxical and ultimately liberating. Hayes examines the tensions between freedom and constraint, abstraction and materialism, linear and synoptic order, that pervade not only philosophic and scientific discourse, but also epistolary writing, fiction and criticism. Drawing on the insights of a wide range of theorists from Adorno, Habermas and Foucault to Deleuze and Derrida, she offers a dialogue between the eighteenth century and our own, an ongoing exploration of the question, 'what is Enlightenment?'.
