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Enhanced conversion of light at TiO2 photonic crystals to the blue of a stop band and at TiO2 random films sensitized with Q-CdS: Order and disorder
No full textSignificant enhancements in the conversion of light to current were observed at the blue edge of TiO2 inverse opals (i-TiO2-o) and at highly disordered TiO2 films (i-TiO2-d) sensitized with Q-CdS in sulfide electrolyte. i-TiO2-o with stop bands centered at 390 and 450 nm were modified with mercaptopropionic acid-Q-CdS with absorption edges tuned to the red or to the blue of the stop-band edges. A 4.7 average enhancement factor was measured at the blue edge of the stop band when it coincided with low Q-CdS absorption, while a 1.4-1.8 average gain was measured at the red edge. The blue-edge gain can be ascribed to localized or slowed light in the low refractive index medium and was found to extend 30-70 nm to the blue of the stop-band center. Light localization effects were suppressed when the stop-band edges overlapped with appreciable absorption. A highly disordered TiO2 film fabricated by replicating a template from 150, 190, and 243 nm diameter polystyrene spheres exhibited a similar gain per adsorbed Q-CdS in the same spectral window as the blue edge of the photonic crystal when quantum dot absorption was low. This gain is ascribed to slowed light resulting from the interference of multiple internal scattering events in the disordered medium. © 2010 American Chemical Society.Albada M. P. 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Enhanced solar energy conversion at quantum dot sensitized TiO2 photonic crystals and disordered films by slow light effects
No full textSuppressed group velocity of light near the stop band edges of photonic crystals and multiple internal scattering in disordered films can be exploited to amplify light energy conversion by increasing photon transit time. TiO2 inverse opals (i-TiO2-o) were sensitized with Q-CdS and Q-CdSe having absorption edges tuned to the red or to the blue of stop bands. Significant enhancements in the conversion of light-to-current per adsorbed quantum dot were measured at the blue-edge of i-TiO2-o compared to sensitized nanocrystalline TiO2, reaching an average of 4.7-fold at Q-CdS-i-TiO2-o in sulfide electrolyte, and were significantly greater than observed at the red edge (1.4-1.8). Similar gains were measured at sensitized disordered TiO2 films with 2 or 3 pore sizes. The gains are ascribed to slow light at the blue edge of the stop band, or to multiple internal scattering in disordered films. Effects of order and disorder on light localization will be discussed
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
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