1,720,974 research outputs found
MECHANICAL ALLOYING OF IMMISCIBLE CU(70)TM(30) ALLOYS (TM=FE,CO)
No full textFour series of copper-based alloys with compositions Cu70Co30, Cu70Fe30Cu70Co15Fe15 and Cu-70(CoFe)(30) were synthesized by mechanical alloying (MA). The interest in these materials is as parents of alloys which will show the giant magnet resistance (GMR) effect. The structural evolution was studied as a function of the MA time by means of Mossbauer spectroscopy, X-ray and neutron diffraction techniques and differential scanning calorimetry (DSC). In spite of the positive heat of mixing of the alloy constituents, the complete dissolution of the minority phases (iron and/or cobalt) into the copper f.c.c. lattice was observed for each specimen after 16 h of MA. This alloying was accompanied by changes in lattice parameter \Delta a(0)/a(0)\ of up to 0.5% with respect to pure copper. Analysis of the crystallization products arising from DSC treatments up to 600 degrees C revealed a separation into copper f.c.c. and iron-based b.c.c, phases. In the case of the ternary Cu-70(FeCo)(30) alloys, the FeCo intermetallic compound was obtained by heating both alloys which originated as ternaries and also as pseudo-binaries based on copper plus the intermetallic phase. Mossbauer spectra of the annealed Cu70Fe30 specimens also revealed a non-magnetic phase of iron with a f.c.c. environment, which was probably stabilized by the presence of copper and small quantities of nitrogen
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
A study of Cu<sub>50</sub>Fe<sub>50</sub> produced by mechanical alloying and its thermal treatment
No full textA specimen of Cu50Fe50 equiatomic composition was mechanically alloyed (MA) by ball milling starting from the pure elements, which are immiscible according to the equilibrium phase diagram. Structural analysis by x-ray and neutron diffraction has shown that the mechanical process initially reduces the crystallite size of both elements as a function of the milling time. The diffraction data show that the bcc iron phase is subsequently consumed, due to progressive incorporation of the iron atoms into the fcc copper matrix. The Mossbauer spectra of a specimen MA for 16 h has a broad magnetic profile typical of a Fe-Cu extended solid solution, with some evidence of two local environments of the iron atoms and a small admixture of the gamma-Fe. The annealing of these MA treated specimens effects a decomposition of the extended solid solution into FCC copper and both alpha- and gamma-iron allotropes. This decomposition process is discussed in relation to spinodal decomposition and to nucleation-and-growth mechanisms
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
The composition and texture constrains on micro-porosities of dolomite reservoirs, Tarim Basin, NW China
No full textDispelling 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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