1,721,000 research outputs found
HYDROGEN ADSORPTION AND DESORPTION ON ALUMINA SUPPORTED PLATINUM-MULTICOMPONENT CATALYSTS WITH A GAS-CHROMATOGRAPHIC PULSE TECHNIQUE
No full textA study of hydrogen chemisorption of multicomponent catalysts containing platinum as an active metal was performed by means of the pulse-flow chromatographic technique. Several series of adsorption experiments, performed at various constant intervals of time between hydrogen pulses, were carried out on each catalyst. During the experiments hydrogen desorption phenomena were observed. Hydrogen desorption was kinetically studied. The rate coefficients of the desorption reaction relevant to each catalyst were evaluated. Desorption has been discussed taking into account spillover effects. The occurrence of desorption phenomena gave rise to apparent adsorption parameters (i.e. platinum dispersion, platinum surface area), however proper parameters have been obtained by graphical extrapolation
Comparison of the acidity of zirconium phosphate with one dispersed in silica, an FT-IR study
No full textThe gas-phase methylation of phenol and m-cresol as a method to discriminate acid and basic surface properties of Mg(Li)/Me (Me=Al, Cr, Fe) mixed oxides
No full textThe gas-phase methylation of phenol and m-cresol as a method to discriminate acid and basic properties of Mg(Li)/Me (Me=Al, Cr, Fe) mixed oxides
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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
How basic properties of MgO-based mixed oxides affect the catalytic performance in gas-phase and liquid-phase methylation of m-cresol
No full textVariations 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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