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Solid state equilibria in the system Al2O3-La2O3-Cr2O3: Reactivity catalyst/support LaCrO3/Al2O3
No full textThe zone of the ternary system Al2O3-La2O3-Cr2O3 delimited by LaCrO3, LaAlO3, Al2O3 and Cr2O3 has been examined. The existence of an extended field of mixed crystals with rhombohedral symmetry LaAl1-xCrxO3 (0≤x≤0·85) has been verified. On the other hand, for x>0·85, the solids show XR diffraction spectrograms typical of the orthorhombic phase LaCrO3. It has been found a small isomorphous substitution of Al3+ by Cr3+ in the β-alumina type phase, leading to the formation of the LaAl11-x CrxO18 series (0≤x≤0·75); moreover, the existence of Al2-xCrxO3 (0≤x≤2) mixed crystals field has been confirmed. Finally it has been experimentally verified that catalytic systems formed by mechanical mixtures of LaCrO3 and Al2O3 prepared anyhow (LaCrO3 dispersed or supported on Al2O3) result thermodynamically unstable whatever the composition
Effect of neutron irradiation on the normal state and superconducting properties of ceramic YBa2Cu307-delta
No full textAbout the role of a surfactant leading to a high performance nanostructured LiFePO4/C cathode
No full textEffect of phosphate ions on the surface chemistry and microstructure of amorphous alumina.
No full textLow-flux neutron irradiation of ceramic YBa2Cu3O7−δ
No full textPellets of sintered YBa 2Cu 3O 7-δ with three different oxygen contents have been irradiated with fast neutron beams of energies 6.5, 3.3 and 4.4 MeV at fluences of 7.7·10 4, 1.3·10 5 and 1.4·10 9 n/cm 2, respectively. The radiation damage has been investigated by comparing the critical temperature (T c mid ), the zero resistivity and the onset temperature before and after neutron irradiation. The critical current has been measured for a few samples in the same experimental conditions. In all transport measurements two different responses to the neutron radiation are observed and discussed
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
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