1,721,197 research outputs found
Electron Spectroscopy Study of Correlation Mechanisms in CuGeO3 Single Crystal
No full textX-ray (Al-K alpha) and resonant Cu 2p-->3d and Cu 3p-->3d photoemission valence-band spectra of high-quality CuGeO3 single crystals are reported and interpreted. In addition, an attempt is given to evaluate the charge transfer (Delta), the d-d Coulomb interaction (U-dd) energies, and the superexchange term (J) on the basis of L(2,3)M(4,5)M(4,5)-L(2,3)M(2,3)M(4,5) Auger transitions, and core-level spectra analyzed within the frame of the Anderson Hamiltonian in the impurity limit. The results clearly show that one-electron band-structure calculations do not account for the band gap approximate to 3.7 eV [M. Bassi, P. Camagni, R. Rolli, G. Samoggia, F. Parmigiani, and A. Revcolevschi (unpublished)] and the emission arising from many-body effects (correlated d(8) and d(8)-d(9) L hybridized states), while Delta and U-dd, found to be approximate to 4.2 and approximate to 6.7 eV, respectively, allow us to classify this compound as a charge-transfer insulator with a strong ionic character. In addition, energy-dependent electron-energy-loss measurements suggest that the forbidden d-d intraband transitions are centered at approximate to 1.6 eV, which justifies the blue color of CuGeO3, and the band gap is approximate to 3.7 eV, as required by the transparency of the crystal in the visible region of the electromagnetic spectrum. Finally, in the approximation allowed by the present models, J results to be of the order of -7 meV
A laser Doppler velocimeter for pulsatile water flow measurements in resonant hydraulic circuits
No full textDescribed is a laser Doppler velocimeter designed to measure a small oscillatory velocity component superposed to the steady water flow of a resonant hydraulic circuit in fully developed turbulent conditions. A frequency tracker with lock-in analysis of the velocity output is used. The rms amplitude of the oscillatory velocity component is measured with an accuracy of 1.5 mm s-1, and the mean velocity is about 3 ms-1. The resonance behaviour of the velocity amplitude measured at a fixed point of the circuit is reported for the exciting frequency range 2–5 Hz
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
Frontiers in FEL physics and related topics. Proceedings, International workshop, La Biodola, Elba, Italy, September 8-14, 2007 in Nuclear instruments and methods A 593(2008).
No full text
Electron Spectroscopy Investigation of the Bi2Sr2 CaCu2O8 and Bi2Sr2 CaCu2O8+y Single Crystal Cleaved Surfaces
No full textStudy by UPS of the electronic struc ture of Bi2Sr2CaCuO8 single crystals and O doping effects
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
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