1,721,027 research outputs found
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
Vibrational - Electrical Properties Relationship in Donor Doped TiO2 by Raman Spectroscopy
No full textTransparent conducting TiO2, obtained by Nb or Ta doping of the anatase structure, is gaining increasing attention for the development of transparent electrodes. Usually, regardless the deposition technique, a crystallization process in reducing atmosphere is necessary to achieve large mobility; in addition, electrical and optical properties are also strongly sensitive to the oxygen deposition pressure. These facts reveal that the defect chemistry of donor doped TiO2 is not trivial and involves a strict interplay among extrinsic dopant atoms, oxygen vacancies and ‘electron killer’ defects such as Ti vacancies and O interstitials. We here present a Raman characterization of donor-doped TiO2 films synthesized under several deposition and post-annealing conditions, employing different doping levels and dopant elements (i.e.
Ta and Nb). Correlations between structure, crystallinity, shift and width of Raman peaks and electrical properties are shown and discussed. In particular, a clear relationship between the shift of the Eg(1) anatase Raman mode and the charge carrier density is found, while the B1g(1) mode connected to Ti-Ti vibrations is significantly affected by the extrinsic doping level. In this complex framework Raman
spectroscopy can provide an invaluable contribution towards understanding the material structure and its influence on the functional properties
Mesoporous silicon nanostructures by pulsed laser deposition as Li-ion battery anodes
No full textSilicon is very attractive as active material for Li-ion battery anodes due to its high theoretical capacity, but proper nanostructuring is needed to accommodate the large volume expansion/shrinkage upon reversible cycling. This would overcome the destructuration induced by the lithiation/delithiation processes, often resulting in poor long-term performance. Hereby, novel mesoporous silicon nanostructures are grown at room temperature by Pulsed Laser Deposition (PLD) directly on top of the Cu current collector surface, and their promising electrochemical behaviour demonstrated in lab-scale lithium cells. Depending on the porosity, easily tunable by PLD, initial specific capacities approaching 300 μAh cm2 are obtained with a quasi-stable reversible cycling. Engineering voids at the nanoscale, by direct introduction of specific porosity during growth, opens up the route for the effective use of silicon as lithium battery anode without the need for any binder or conductive additive which would lower the overall energy density
Mesoporous Si and Multi-Layered Si/C Films by Pulsed Laser Deposition as Li-Ion Microbattery Anodes
No full textSilicon is a very attractive Li-ion battery anode material due to its high theoretical capacity, but proper nanostructuring is needed to accommodate the large volume expansion/shrinkage upon reversible cycling. Hereby, novel mesoporous Si nanostructures are grown at room temperature by simple and rapid Pulsed Laser Deposition (PLD) directly on top of the Cu current collector surface. The samples are characterized from the structural/morphological viewpoint and their promising electrochemical behavior demonstrated in lab-scale lithium cells. Depending on the porosity, easily tuneable by PLD, specific capacities approaching 250 μAh cm−2 are obtained. Successively, newly elaborated bi-component silicon/carbon nanostructures are fabricated in one step by alternating PLD deposition of Si and C, thus resulting in novel multi-layered composite mesoporous films exhibiting profoundly improved performance. Alternated deposition of Si/C layers by PLD is proven to be a straightforward method to produce multi-layered anodes in one processing step. The addition of carbon and mild annealing at 400°C stabilize the electrochemical performance of the Si-based nanostructures in lab-scale lithium cells, allowing to reach very stable prolonged reversible cycling at improved specific capacity values. This opens the way to further reducing processing steps and processing time, which are key aspects when upscaling is sought
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
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