1,722,914 research outputs found
Magnetostriction and magnetisation of praseodymium and some rare earth intermetallic compounds in pulsed magnetic fields
No full textThe magnetostriction of polycrystalline cubic laves phase compounds of the form RFe,has been measured at temperatures in the range 5.3K - 300K in pulsed magnetic fields of up to 18 tesla. The specific compounds studied are GdFe2, HoFe2, ErFe, LuFe2 and CeFe2. The single crystal magnetostriction constants )i,oo, A, and the saturation magnetostriction as have been estimated for each compound. In the case of CeFe2, sharp increases in the magnetostriction curves were observed at fields of around 3 tesla and at temperatures below 150K; magnetisation measurements for CeFe2 have also been made on the same sample. The magnetisation curves show signs of a first order increase at the same fields but the change in magnetisation is much smaller than the change in magnetostriction. Magnetostriction and magnetisation of a single crystal of Praseodymium has been measured at pulsed fields up to 18 tesla and in the temperature range 3K - 78K. The measurements were made along all three principal axes and the transverse magnetostriction was also measured in each case. These results are analysed using a molecular field Hamiltonian. The dominant strain dependent interaction is shown to arise from the crystal field. Also no spontaneous magnetic ordering was observed down to - 3K. The magnetostriction of single crystal NdAI2 has been meac+aed in fields up to 2 tesla along the easy axis [ 100] and in fields of up to 18 tesla along the hard axis [ 1111. The measured strains are explained in terms of a single-ion Hamiltonian. The second order magnetoelastic coefficients are found to be Mi =- 31.7 K/ion and Me = 65.1 ± 7.5 K/ion. The measurements also show that the magnetic domains are unequally distributed among the six equivalent (100] easy directions. From a comparison of the longitudinal and transverse strains it was found that P = 0.48 t 0.03 (where P is the volume fraction of domains along the direction of measurements [ 100] ) and was independent of temperature for the crystal used.The magnetostriction of an ErZn single crystal was also measured between 5.7K and 78K using pulsed fields up to 18 tesla. The measurements along the easy axis [ 100] were performed on a (100) plane disc. The magnetostriction constant h, has been determined from the measurements along the easy' [1001 axis. The longitudinal and transverse strains show that the magnetic domains are equally distributed among the equivalent easy directions. Measurements along the hard axis [ 111] have not been successful.</p
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
Editorial [Hot Topic: Physical Layer Optimisation for Digital Broadcast Network (Guest Editor: Karim M. Nasr)]
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