1,721,007 research outputs found
The Internal Impedance of Traction Rails for DC Railways in the 1-100 kHz Frequency Range
No full textThe electrical behavior of the sample steel traction rails is analyzed, considering the resistance and internal inductance. Measurements are performed on a sample rail with a circulation of audiofrequency current (with frequency regulated on a wide frequency interval range of 1–100 kHz) superimposed on a dc supply current. The results complete the other measurement results obtained with a 50-Hz bias current; the resistance values are 30%–50% smaller, whereas the internal inductance is almost similar
Electron correlation effects on the hydrogen passivation of Mn(x)Ga(1-x)As dilute magnetic semiconductors
No full textStabilizing effects of n-type doping on Fe and Mn acceptors in III-V compounds
No full textAn n-type doping significantly increases the number of active, Fe atoms substituting In (FeIn) in Fe-implanted InP. A previous theoretical study has shown that donor-acceptor pairs have direct stabilizing effects on Fe_In related to charge rearrangements strongly localized at the Fe site and involving d orbitals. Here, we extend that study to Fe and Mn acceptors in InP and GaAs. Present results show that the theoretical model proposed for FeIn in InP generally holds for Fe and Mn acceptors in III-V semiconductors
A research program for the planning of energy transmission systems through microwave beams and evaluation of the related environmental impact
No full textGoing 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
Structural and Electronic Properties of Sodalite: An ab Initio Molecular Dynamics Study
No full textStructural, vibrational, and electronic properties of crystalline sodalite are analyzed using ab initio molecular dynamics based on density functional theory (Car-Parrinello method). This is the first theoretical study of sodalite based on first principles, in which the full periodicity of the lattice is explicitely taken into account. The computed structural and vibrational properties are in good agreement with available experimental data. The dependence of such properties upon different ions inside the sodalite framework show the correct trend. We have also analyzed the properties of the neutral sodalite framework with no interframework atoms: this ideal structure is found to be stable and metallic; its electronic structure elucidates the origin of the active sites of this material. Moreover we have synthesized and characterized two sodalites: hydroxysodalite and hydrosodalite. Photoelectron spectroscopy and fouler transform infrared spectroscopy data for these materials are shown
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
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