1,720,953 research outputs found
Fibras ópticas adelgazadas recubiertas con P3HT-RR para aplicación de sensado
Get PDFLa presente tesis aborda la investigación teórica, el estudio y el análisis
modal de las guías de onda de simetría cilíndrica describiendo de forma puntual sus
características, parámetros y ecuaciones que gobiernan tanto su funcionamiento y
condiciones que le permite ser un canal de transmisión de radiación
electromagnética, como lo es la fibra óptica monomodal con salto de índice gradual,
así como la construcción y fabricación de distintos perfiles modificando su estructura
geométrica transversal mediante la técnica de fusión calentamiento-estirado dando
origen a las microestructuras llamadas fibras ópticas adelgazadas (tapers).
Estas microestructuras fabricadas poseen ventajas para el desarrollo y
aplicabilidad en sensores ópticos, debido a que facilitan la reproducción de zonas
con campos evanescentes más intensos. Cuando a dichas microestructuras se
incorporan mediante la técnica de depósito por goteo materiales poliméricos con
propiedades de conductividad eléctrica generan y reproducen cierto tipo de
fenómeno físico en la interfaz fibra óptica-polímero conocidos como resonancias
electromagnéticas.
A partir de la técnica numérica avanzada modelado de elementos finitos
integrada en el software de simulación COMSOL Multiphysics, del cual se utiliza la
herramienta Análisis Modal, se analizan y discuten los resultados obtenidos por el
modelo de cuatro perfiles geométricos distintos representando a la zona transversal
adelgazada de una fibra óptica más el perfil de la fibra óptica estándar sin modificar
a tres diferentes longitudes de operación para cada uno. Lo anterior, con el fin de
observar e identificar los modos de propagación que conforman a los primeros
cuatros grupos de los modos linealmente polarizados y distribuciones de la
intensidad de potencia incidente.
Finalmente, se concluye con la respuesta espectral, curva de absorción y
transmitancia de la fibra óptica adelgazada que se construye y fabrica a partir de la
metodología experimental descrita recubierta con el material polimérico e induciendo
microcurvaturas de forma mecánica para la evaluación y respuesta sensitiva de
estas configuraciones para la investigación y desarrollo sensores ópticos.The present thesis addresses the theoretical research, study and modal
analysis of cylindrical symmetry waveguides, describing their characteristics in a
specific way, parameters and equations that govern both its operation and conditions
allowing it to be a channel of transmission of electromagnetic radiation as is the
monomodal optical fiber with gradual index jump, as well as the construction and
manufacture of different profiles modifying their transverse geometric structure by
means of the heating-stretch fusion technique giving rise to the microstructures
called thinned optical fibres (tapers).
These manufactured microstructures have advantages for the development
and applicability in optical sensors because they facilitate the reproduction of areas
with more intense evanescent fields than by incorporating polymeric materials with
drop casting technique electrical conductivity properties generate and reproduce a
certain type of physical phenomenon at the fiber-optic interfacepolymer known as
electromagnetic resonances.
From the advanced numerical finite element modeling technique integrated in
the COMSOL Multiphysics simulation software of which the Modal Analysis tool is
used, the results obtained by the model of four different geometric profiles are
analyzed and discussed representing the thinned cross-section of an optical fibre
plus the unmodified standard optical fibre profile at three different operating lengths
for each in order to observe and identify the propagation modes that make up the
first four groups of linearly polarized modes and distributions of incident power
intensity.
Concluding, with the spectral response, absorption and transmittance curve of
the thinned optical fiber that is constructed and manufactured from the experimental
methodology described coated with the polymeric material and inducing
microcurvaturas mechanically for the evaluation and sensitive response of these
configurations for research and development of potential optical sensor systems
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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