1,720,959 research outputs found
LINAC à électrons en bande S pour ThomX
No full textThomX est une source de rétrodiffusion qui vise à fournir un flux moyen de photons d'environ 10¹²-10¹³ ph/s dans la gamme des rayons X durs (40-90) keV. Ma thèse porte sur l'étude et la conception du linac ThomX et du son upgrade en bande S, à savoir le canon RF et les deux sections accélératrices que sont des structures à ondes progressives. Tout d'abord, la thèse met en évidence la physique de la diffusion Compton inverse avec une description de la cinématique des collisions entre photons et électrons. En outre, elle donne une explication générale du flux de photons Compton et de la luminosité ainsi que les principales applications possibles de la machine ThomX sont discutées. En outre, la thèse explique en détail la source radiofréquence (RF) de haute puissance pour la machine ThomX, à savoir le modulateur qui est du type ScandiNova K2-2 et le Klystron qui est du type Toshiba E 37310, y compris les résultats des tests d'acceptation. Elle comprend également le développement des composants du réseau, tels que le diviseur de puissance, le circulateur de puissance, les déphaseurs et les atténuateurs, ainsi que les tests de faible puissance RF de ces composants. Ma thèse fournit également les caractéristiques électromagnétiques du linac ThomX, à savoir la structure quasi gradient de l'injecteur linac LEP (LIL) et le canon RF, ainsi que la configuration des solénoïdes en utilisant CST Studio Suite. Je présente également les caractéristiques du système de refroidissement du linac ThomX, l'analyse thermique et les tests du système de vide. Le commissioning du linac ThomX est effectuée en deux parties: le conditionnement RF et l'obtention du premier faisceau. La mesure de la charge, à l'aide de l'ICT, et les mesures d'énergie, à l'aide d'aimants orientables ont étaient utilisés pour caractériser le faisceau. En outre, des modèles d'approximation analytiques pour l'énergie et la propagation de l'énergie dans les structures à ondes stationnaires et progressives sont proposés et ajustés aux mesures. En outre, un travail expérimental réalisé sur le photoinjecteur PHIL est présenté pour les mesures de l'énergie du faisceau et de la propagation de l'énergie en utilisant un aimant dipôle dans le but d'acquérir des compétences pratiques avant la mise en service de ThomX. Ma thèse présente également la simulation et l'analyse électromagnétique de la structure à gradient constant (CG) à double alimentation qui sera installée en remplacement de la structure LIL. Ma thèse détaille le processus de fabrication de cette structure, tel que l'usinage, le brasage et l'alignement, qui sont réalisés en collaboration avec la société Research Instruments (RI) en Allemagne. Pour finir, le test de faible puissance et la mise en accord de la structure sont effectués en utilisant la technique du "bead-pull" et les résultats sont comparés aux résultats de la simulation et aux spécifications techniques.ThomX is a back scattering source that aims to provide an average photon flux of about 10¹² -10¹³ ph/s in the hard X-ray range (40-90) keV. The framework of my thesis focuses on the design study of the S-band ThomX linacs, namely the RF gun and the travelling wave accelerating structures. First, the thesis highlights the physics of Inverse Compton Scattering with a description of the kinematics of the photon and electron collisions. In addition, it gives a general explanation of the Compton photon flux and the brightness. The main possible applications of the ThomX machine are briefly discussed. Moreover, the thesis describes in detail the high power radio-frequency (RF) source used for the ThomX machine, namely the ScandiNova modulator K2-2 and the Toshiba Klystron E 37310 including the acceptance test results. As well as, it includes the development of the network components, such as the power divider, power circulator, phase shifters and attenuators performing the RF low power tests of these components. Additionally, the dissertation also provides the electromagnetic characteristics of the ThomX linac, namely the LEP injector linac (LIL) quasi gradient structure and the RF gun, and solenoid configuration using CST Studio Suite. Moreover, it introduces the cooling system characteristics of the ThomX linac, the thermal analysis and the vacuum system tests. The commissioning of the ThomX linac is performed including the RF conditioning and the first beam commissioning. During the beam commissioning, the charge measurement using an integrated current transformer (ICT), and the energy measurements using steerer magnets are described. Furthermore, analytical approximation models for the energy and the energy spread, in standing and travelling wave structures, are proposed and fitted with measurements. In addition, an experimental work carried out at the PHIL photoinjector is introduced for the beam energy and energy spread measurements, using a dipole magnet for a purpose of acquiring practical skills before the ThomX commissioning. The dissertation also demonstrates the electromagnetic simulation and analysis of the dual feed constant gradient (CG) structure, which will be installed as a replacement of the LIL structure. The fabrication process of this structure such as machining, brazing, alignment and backing out, which are performed in collaboration with research instruments (RI) company in Germany, are explained in detail. Finally, the tuning and the low power test are performed using the bead-pull technique, and the results are compared with simulation data and with the technical specifications
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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