1,720,969 research outputs found
High throughput physical vapor deposition growth of Pb(Zr<sub>x</sub>Ti<sub>1-x</sub>)O<sub>3 </sub>perovskite thin films growth on silicon substrates
No full textThe integration of lead zirconate titanate (Pb(ZrxTi1-x)O3) (PZT) compounds on Si substrates with a smooth surface would provide a key technology for silicon photonic devices. The quality of the deposited thin film is critical in order to integrate Pb(ZrxTi1-x)O3 on Si substrates for applications such as pyroelectric mid-infrared detectors or optical modulators. Here, we have applied physical vapour deposition technique using a modified molecular beam epitaxy tool to deposit perovskite Pb(ZrxTi1-x)O3 on Si and Pt substrates. We have developed a method to grow crack-free PZT films on Si substrates. The fabrication procedure entailed the use of TiO2 as a buffer layer and post annealing of the PZT/TiO2/Si films under oxygen atmosphere. Cross section Scanning Electron Microscopy images enabled the identification of two distinct layers: PZT and TiO2, which was also confirmed by Spectroscopic Ellipsometry. X-Ray Diffraction patterns indicated the transition from the rhombohedral to the tetragonal phase and the formation of the perovskite phase of Pb(Zr0.44Ti0.56)O3
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
Photoluminescence of Tm-doped Ta<sub>2</sub>O<sub>5</sub> waveguides
No full textPhotoluminescence is observed from tantalum pentoxide thin film waveguides, doped with 3 wt% of Tm2O3 (Tm:Ta2O5), in the wavelength range of 1.6 to 2.1 μm. Maximum emission was obtained using a pump wavelength of 795 nm, which corresponds to the excitation of thulium ions to the 3H4 manifold. The effect of post-deposition annealing temperature and duration on the photoluminescence lifetime and intensity was investigated. This is the first report of photoluminescence around 1.8 μm and lifetime measurements of Tm:Ta2O5 films with potential for gain in a planar platform
Mid-infrared all-optical modulation in low-loss germanium-on-silicon waveguides
No full textAll-optical modulation has been demonstrated in a germanium-on-silicon rib waveguide over the mid-infrared wavelength range of 2-3µm using a free-carrier absorption scheme. Transmission measurements have shown the waveguides to have low propagation losses that are relatively independent of wavelength out to 3.8µm, indicating that the modulation could be extended further into the mid-infrared region for applications in sensing and spectroscopy. By monitoring the material recovery, the free-carrier lifetime of the micron-sized waveguides has been estimated to be ~18ns, allowing for modulation speeds within the megahertz regime
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
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