1,721,029 research outputs found
Surface States of the (110) Surface of GaAs
No full textResults are presented of a new calculation of the surface states at the (110) surface of GaAs. By using Koster-Slater parameters fitted to bulk optical and photoemission data, the surface band structure has been calculated with a LCAO method. The main conclusion is the existence of two surface bands, one inside the band gap at about 1 eV from the top of the valence band and the other a few tenths of an eV below it. The results show good agreement with the available experimental data
Intrinsic Surface States in III-V Compounds
No full textThe electronic structure of the (110) face of GaAs, GaP and InSb is investigated using a realistic tight-binding model. Calculations of the surface band structure are presented and the nature of the various surface bands is discussed. The results are in agreement with the experimental data and provide a quantitative description of the cation-derived surface states lying in the bulk band gap
Surface States in Ionic Crystals: Calculation for CsBr
No full textThe Green's function approach has been applied to surface electron states together a realistic model of bulk band structure of ionic crystals for the calculation of surface energy band structure of the (110) face of simple cubic CsBr. The results, which supply the first accurate test of the method, are in agreement both with the main trend of the experimental data for ionic crystals and with previous theoretical evaluations
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
Valence Charge Density in Aluminum
No full textA comparison is made between the valence charge density obtained using a local on Fermi sphere potential and that derived from a suitable average potential which takes into account the effects due to the nonlocality of the pseudopotential. The two electron distributions present significant differences, showing that the calculation of the valence charge density, which does not take account of the nonlocality of the pseudopotential, can lead to uncertain results
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