1,720,959 research outputs found
The effect of CoSn/CoSn2 phase ratio on the electrochemical behaviour of Sn40Co40C20 ternary alloy electrodes in lithium cells
No full textSamples of a SnCoC-based electrodes, all having the molar composition Sn40Co40C20, but differing by the high energy ball milling synthesis
conditions, have been tested in lithium cells. The investigation was carried out by using a series of complementary techniques, including potentiodynamic
cycling with galvanostatic acceleration, galvanostatic charge–discharge cycling and impedance spectroscopy. The results confirmed
the high capacity delivery of this type of ternary electrodes but also revealed that their electrochemical behaviour is influenced by the relative
abundance of the nanosized domains of CoSn and CoSn2 in their structure
Development of gel-polymer electrolytes and nano-structured electrodes for Li-ion polymer batteries RID A-5377-2011 RID A-5189-2011
No full textA novel methacrylic gel-polymer membrane
was synthesized by free radical photo polymerisation (UVcuring
technique). The polymerisation was very easy, fast
and reliable and the membrane shows good behaviour in
terms of both conductivity and cyclability in Li cells. The
anode materials were prepared by high energy ball milling
obtaining nanocrystalline Ni–Sn alloys, while the hydrothermal
processing in presence of a template was used to
prepare nanostructured LiFePO4/C as cathode material.
Every component has been characterised separately from
the structural and electrochemical point of view. The first
experimental data on the performance of a complete Li-ion
polymer cell assembled with the components studied are
also presented. The results obtained demonstrate the
overall satisfying, and some superior performances of the
various single components and their feasibility as a complete
system
Activation of the reactive hydride composite 2NaBH(4) + MgH(2) RID A-2096-2009 RID B-4391-2009
No full textA novel method to enhance the reaction kinetics of the reactive hydride composite 2NaBH4 + MgH2 is described. It has been discovered that short-term exposure to a moist atmosphere has a very beneficial effect on the desorption reaction of the 2NaBH4 + MgH2 mixture. By this procedure it is possible to achieve, after drying, both faster desorption kinetics and greater amounts of released hydrogen compared to ball-milled material without further treatment
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
Experimental Evidence of Ca[B(12)H(12)] Formation During Decomposition of a Ca(BH(4))(2) + MgH(2) Based Reactive Hydride Composite RID A-2096-2009 RID B-4391-2009
No full textThe combination of Ca(BH4)2 and MgH2 materials results in a composite with remarkable hydrogen storage properties. However, full reversibility upon the (re)hydrogenation reaction has not yet been achieved. The poor reversibility is shown to be linked to the formation of stable intermediate phases or side products upon decomposition. In this work, we show, for the first time, the clear experimental evidence of CaB 12H12 among the decomposition products of a Ca(BH 4)2 + MgH2 composite. A combination of 11B Magic Angle Spinning-Nuclear Magnetic Resonance ( 11B{1H} MAS NMR), ex situ X-ray diffraction (XRD) and Rietveld analysis are presented. An assessment of the (de)hydrogenation and (re)hydrogenation reactions of Ca(BH4)2 + MgH2 composite is reported. The experimental results provided in this work highlight the reasons for the limited reversibility observed in the Ca(BH 4)2 + MgH2 composite upon (re)hydrogenatio
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