1,721,001 research outputs found
BAND-STRUCTURE AND ELECTRONIC-PROPERTIES OF FESI AND ALPHA-FESI(2)
No full textThe results of self-consistent linear muffin-tin orbital calculations for the ordered end members of the FeSi1+x series, i.e., FeSi (x = 0) with a CsCl structure and alpha-FeSi, (x = 1) with a tetragonal structure, predict semimetallic behavior for FeSi and metallic behavior and higher stability for alpha-FeSi2. The valence band density of state features of the alpha-FeSi2 differ slightly from those of the cubic fluorite (gamma-FeSi2). The analysis of the valence band photoemission spectra taken on silicide thin films epitaxially grown on Si(111) substrates estimates the composition of the mono- and disilicide phases present in the annealed films but does not determine the proposed formation of the distorted fluorite structure (alpha-FeSi2) well below its bulk stabilization temperature of 950-degrees-C
Polariton entanglement in the self-stimulated regime
No full textWe investigate the influence of environmental noise on polariton entangled pairs in the self-stimulated regime. By adopting a recent separability criterion, we show that self-stimulation may suppress the detrimental influence of noise on entanglement, but once effective, a noise-equipped classical model of parametric emission provides the same results of quantum theory with respect to the separability criterion. More generally we show that, in the macroscopic limit, it is not possible to observe violations of local realism with measurements of finite order n -particle correlations only. These results provide a prototypical case of the emergence of macroscopic local realism in the presence of strong entanglement even in the absence of decoherenc
Near-field light emission from mesoscopic complex structures
No full textWe describe a general theoretical scheme for the investigation of light emitted from nano- and micrometric structures of arbitrary shape and composition. The present analysis, based on the Green-tensor technique, allows to better identify the non-trivial relationship between near-field images and fluorescent object
Decoherence-free emergence of macroscopic local realism for entangled photons in a cavity
Full text linkWe investigate the influence of environmental noise on polarization entangled light generated by parametric emission in a cavity. By adopting a recent separability criterion, we show that (i) self-stimulation may suppress the detrimental influence of noise on entanglement, but (ii) once it becomes effective, a noise-equipped classical model of parametric emission provides the same results of quantum theory with respect to the separability criterion. More generally we also show that, in the macroscopic limit, it is not possible to observe violations of local realism with measurements of finite order n-particle correlations only. These results provide a prototypical case of the emergence of macroscopic local realism in the presence of strong entanglement even in the absence of decoherence
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
Electronic energy levels of alfa-Al2O3 from L-edge photoabsrption of aluminum and small-cluster CNDO calculations
No full textAbsorption spectra measured with synchrotron radiation on well-characterized self-supported polycrystalline thin films of α-Al2O3 above the LII,III edge of aluminum are presented. The results are interpreted on the basis of the electron energy levels computed with a new complete-neglect-of-differential-overlap parametrization for a small cluster of atoms cut out from a perfect crystal of aluminum oxide. For the valence states, good agreement is found with the experimental bandwidths and positions and with recent band-structure and density-of-states calculations. The experimental structures up to 10 eV from Al LII,III absorption edge are interpreted as due to transitions to empty levels of the aluminum ion of predominantly s,p, and d character. The interpretation of the outer-most spectral features requires a larger basis set of aluminum orbitals and a bigger atomic cluster
- …
