1,720,979 research outputs found
Ruthenium oxide-added quartz iron phosphate as a new intercalation electrode in rechargeable lithium cells
No full textImproved quartz FePO4 as positive electrode for lithium batteries
No full textFePO4 is a very promising electrode material for lithium batteries. The material is environmentally benign and is characterized by a high theoretical specific capacity (178 Ah/Kg). The application of this material is limited by the poor kinetics of its lithium intercalation process. In this paper we demonstrate that by using a synthesis procedure based on a wet chemistry route, α-quartz iron phosphate electrodes having enhanced electrochemical properties are obtained. The properties of this electrode may be further improved by finely dispersing RuO2 particles throughout its mass. We explain the beneficial effect of RuO2 by assuming that it induces a substantial enhancement of the FePO4 interparticle electronic contact. With this strategy of synthesis and additives we have fabricated electrodes capable of delivering reversible specific capacity as high as 110 mAh/g at a C/3 rate
Superacid ZrO2-added, composite polymer electrolytes with improved transport properties
No full textIn this paper we report the synthesis and the properties of a new composite polymer electrolyte formed by dispersing a sulphatepromoted
superacid zirconia into a poly(ethylene oxide)–lithium tetrafluoroborate, PEO–LiBF4, matrix. We show that the addition of
the superacid ceramic greatly enhances the properties of the electrolyte in terms of improvement of its transport properties, and particularly,
of the lithium transference number. The results, in addition to their practical reflection in the lithium polymer electrolyte battery
technology, also provide a valid support to the model which ascribes the enhancement of the transport properties of ceramic-added composites
to the specific Lewis acid–base interactions between the ceramic surface states and both the lithium salt anion and the PEO-chains
Nanocomposite, PEO-LiBOB polymer electrolytes for low temperature, lithium rechargeable batteries
No full textPolymer electrolytes formed by dispersing a low particle size Al2O3 ceramic filler in a PEO-lithium bis(oxalato)borate, LiBOB matrix, are here presented and discussed. The results demonstrate that these composite electrolytes have unique features which include an extended temperature range of high ionic conductivity, a wide electrochemical stability window and a good control of the lithium metal electrode interface. These features make the electrolyte quite convenient for the development of advanced, solid-state, rechargeable lithium polymer batteries
New types of rechargeable lithium and lithium-ion polymer batteries
No full textThe activities in progress in our laboratory for the development of new types of lithium batteries to be proposed for portable electronics and hybrid car application, are reviewed and discussed. The research has been mainly focused on the characterization of new electrode and electrolyte materials. Results related to improved, solvent-free , as well as gel-type, polymer electrolytes are particularly stressed. It is shown that the use of proper gel electrolytes in combination with suitable electrode couples, allows the development of new types of safe, reliable and low cost lithium ion batteries which appear very promising power sources for hybrid vehicles. copyright The Electrochemical Society
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
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