1,720,991 research outputs found
Contrôle de l'environnement électronique, chimique et optique de nanocristaux colloïdaux pour les LED infrarouges
No full textColloidal quantum dots (CQDs) are semiconductor crystals with radii of a few nanometers, which are synthetized in solution and which present bright and size-tunable emission. Thus, in recent years, CQDs have emerged as a powerful alternative to traditional semiconductors, the growth of which is energetically very costly. While in the visible range the potential of CQDs as light emitters has been widely realized and has reached commercial levels of development, further efforts are still needed in the infrared. In particular, the luminescence efficiency of infrared CQDs tends to drop drastically after their integration into light emitting diodes (LEDs). This is due to a combination of an unbalanced charge injection within the active material, an increased density of non-radiative relaxation pathways in the integrated CQDs, and the trapping of the generated light within the device.During my thesis project, I aimed to address these issues by gaining control over the electronic, chemical, and optical environment of the CQDs inside the LEDs. To achieve this, I employed different methods. First, I tuned the electronic band structure of CQDs by modifying their work function with alkali metal atoms, which I tracked using XPS measurement at the TEMPO beamline of the SOLEIL synchrotron. Then, I regulated the density of trap states at the surface of the CQDs inside the LEDs by a combination of a halide ion treatment which multiplied the efficiency of the LEDs by a factor 3 leading to a record 2.3 % EQE and the cooling of the device which extended the lifetime by two orders of magnitude. I also induced anisotropy in the emission of initially isotropic CQDs by their coupling to two different photonic structures, plasmonic gratings and dielectric microcavities, which has the potential to improve light extraction from LEDs. Lastly, I transferred the coupling to dielectric microcavities to photodetectors, leading to ultrafine photocurrent peaks, which are tunable post-fabrication in the telecom range.Les « quantum dots » (QD) colloïdaux sont des cristaux de semiconducteurs avec une taille de l'ordre de quelques nanomètres, qui sont synthétisés en solution et qui ont une luminescence accordable avec leur taille. Ainsi, dans les dernières années, les QD ont émergé comme une alternative aux semiconducteurs traditionnels, dont la croissance est très couteuse en énergie. Bien que dans le visible le potentiel des QD ait été pleinement réalisé, atteignant une distribution commerciale, des efforts supplémentaires sont encore nécessaires dans l'infrarouge. En particulier, l'efficacité de luminescence des QD infrarouges chute drastiquement lors de leur intégration des diodes électroluminescentes (LED). Cela est dû à une combinaison d'un mauvais équilibre de l'injection des charges dans le matériau actif, d'une densité accrue de chemin de relaxation non-radiatifs dont les QD intégrés, et du piégeage de la lumière générée à l'intérieur du dispositif.Durant mon projet de thèse, j'ai cherché à résoudre ces points critiques en obtenant le contrôle sur l'environnement électronique, chimique, et optique des QD au sein des LED. Pour cela, j'ai eu recours à différentes méthodes. Tout d'abord, j'ai ajusté la structure de bande électronique des QD en modifiant par le dépôt d'atomes de métaux alcalins leur travail de sortie, que j'ai suivi par mesures XPS sur la ligne TEMPO du synchrotron SOLEIL. J'ai ensuite régulé la densité de pièges à la surface des QD dans les LED par une combinaison d'un traitement aux ions halogénures qui a permis de multiplier par un facteur 3 l'efficacité des LED et a mené à une EQE record de 2.3 % et du refroidissement des dispositifs qui a étendu leur durée de vie de deux ordres de grandeur. J'ai également induit une anisotropie dans l'émission des QD initialement isotropes par le couplage à deux types de structures photoniques, les réseaux plasmoniques et les microcavités diélectriques, ce qui a le potentiel d'améliorer l'extraction de la lumière dans les LED. Enfin, j'ai transféré le couplage au microcavité diélectrique à un système de photodétection, menant à des pics ultrafins de photocourant largement accordables dans la gamme télécom
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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