1,720,983 research outputs found
STRUCTURE AND SUPERCONDUCTING PROPERTIES OF PURE AND VARIOUSLY DOPED BULK MgB2 OBTAINED BY UNIAXIAL AND ISOSTATIC HOT PRESSING
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STUDY OF THE SINTERING BEHAVIOUR OF MgB2 SUPERCONDUCTOR DURING HOT-PRESSING
No full textThe densification behaviour of MgB2 was studied when commercial powder was hot-pressed in the temperature
range 1070–1190 C. The mechanisms active during sintering were investigated by continuously recording the shrinkage
vs. time and elaborating the data on the basis of Kingery’s model for liquid phase sintering. XRD and SEM analysis on
final dense bodies were used to evaluate secondary phases formation during sintering and the effect of magnesium
sublimation. AC magnetic susceptibility measurements were also performed to correlate the microstructural and morphological modifications induced by hot-pressing and the superconducting properties
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
From wood to bone: multi-step process to convert wood hierarchical structures into biomimetic hydroxyapatite scaffolds for bone tissue engineering
No full textHydroxyapatite (HA) bone scaffolds characterized by highly organized hierarchical structures have
been obtained by chemically transforming native woods through a sequence of thermal and
hydrothermal processes. The whole chemical conversion has been carried out through five steps from
native wood to porous hydroxyapatite: 1) pyrolysis of ligneous raw materials to produce carbon
templates characterized by the natural complex anisotropic pore structure; 2) carburization process by
vapour or liquid calcium permeation to yield calcium carbide; 3) oxidation process to transform
calcium carbide into calcium oxide; 4) carbonation by hydrothermal process under CO2 pressure for the
further conversion into calcium carbonate; 5) phosphatization process through hydrothermal
treatment to achieve the final hydroxyapatite phase. The five steps of the phase transformation process
have been set up in order to achieve total phase conversion and purity maintaining the original native
microstructure. An innovative biomimetic apatite hierarchically structured in parallel fastened hollow
microtubules has been synthesized, structurally characterized and proposed as a new inorganic
biomorphic scaffold providing a biomimetic nanostructure surface for fascinating bone engineering
applications
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
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