1,721,011 research outputs found
A method to estimate the environmental impact of an electric city car during six months of testing in an Italian city
No full textEffects of Mg doping on the superconducting properties of YBa2Cu3O7 and La1.85Sr0.15CuO4 systems
No full textShielding current density in Mg-doped YBCO-123 as determined by ac Magnetic Susceptibility Measurements
No full text
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
PLANAR TUNNEL-JUNCTIONS ON FE-DOPED Y-BA-CU-O SYSTEMS
No full textWe have measured the tunneling characteristics of planar junctions fabricated on YBa2(Cu1-xFex)3O7 single crystals with different percentages of Fe substitutions. A liquid etched bath (1% Br in methanol, by volume) has been used to remove the degraded surfaces of the high T(c) superconductors. After a short air exposition, the junctions were completed by evaporating Pb thin film counterelectrodes through a metallic mask. In comparison with the undoped 90 K phase, the doped junctions show gap-like structures smeared and reduced in amplitude at about +/-25 mV, while a second feature at about +/-5 mV is present only for slightly doped samples. This fact seems to indicate that Fe is mainly substituting for Cu in the one-dimensional Cu-O chains
Combined experimental and theoretical investigation of optical, structural, and electronic properties of CH(3)NH(3)SnX(3) thin films (X=Cl,Br)
No full textWell-oriented thin films of methyl-ammonium trihalogenostannates CH3NH3SnX3 compounds X=Cl,Br
are grown by the single source thermal ablation technique. Optical absorption and structural analysis of
CH3NH3SnX3 thin films are combined with ab initio calculations in order to clarify their electronic properties
and the role of the organic cation. The structural calculations reproduce well the measured lattice parameters,
and optical measurements reveal a direct gap absorption onset for both compounds, in agreement with the
calculated band structures. It turns out from projected density of states analysis that the valence and conduction
bands take negligible contribution from the methylammonium. It is inferred that the band gap mainly depends
on the ionicity and size of the inorganic cage SnX3
TUNNELING CHARACTERISTICS OF YBA2(CU1-XFEX)3OY JUNCTIONS
No full textThe authors have measured the tunneling characteristics of planar junctions realized on YBa2(Cu1-xFex) 3Oy single crystals with x=0.04. In comparison with the undoped 90 K phase of this material, the conductance curves of the doped junctions show gap-like structures broadened and reduced in amplitude. This behavior is similar to what has been observed in junctions fabricated on YBa2Cu3O7-δ single crystals with Tc=60 K. At low temperatures the background conductance is linear up to about 100 mV and shows a parabolic behavior for higher voltages, as found in the undoped 90 K system. From the analysis of the parabola, the barrier height and thickness are deduced. In the doped junctions anomalies are frequently observed as a conductance peak centered at zero-bias. They appear to result from scattering that involves spin exchange between tunneling electrons and Fe ions localized at the metal-oxide interfac
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