1,720,998 research outputs found
An Improved Version of a Sequential Design Criterion for Discriminating Among Rival Multiresponse Models
No full textState of Supported Rhodium Nanoparticles for Methane Catalytic Partial Oxidation (CPO): FT-IR Studies
No full textOn the consistency of data obtained from different techniques concerning the surface structure of vanadia-titania catalysts: Reply to the comment of Israel E. Wachs
No full textFourier transform-infrared study of the adsorption and coadsorption of nitric oxide, nitrogen dioxide and ammonia on vanadia-titania and mechanism of selective catalytic reduction
No full textThe adsorption of nitric oxide, nitrogen dioxide and ammonia and their coadsorption on vanadia-titania have been studied by FT-IR spectroscopy. Upon nitric oxide adsorption, a surface nitrosyl species is formed rapidly and nitrates are formed slowly by oxidation. Nitrogen dioxide adsorption forms nitrate species by oxidation and nitric oxide. Lewis-bonded molecular species and ammonium ions are formed upon ammonia adsorption. Coordinated ammonia is thermally more stable than ammonium ions and can lose an hydrogen atom to give an amide species. Adsorption on a water-covered sample shows that ammonia displaces water from Lewis sites. Experiments of nitric oxide adsorption on ammonia-covered vanadia-titania show that ammonia poisons the nitric oxide adsorption sites and that NO3- species are formed by nitric oxide oxidation on vanadyl sites. By heating the ammonia-covered sample in the presence of gaseous nitric oxide coordinated ammonia reacts via the amide species, while ammonium ions do not. The fol lowing reaction mechanism is proposed: VO2+ + NH3 = [HO-V-NH2]2+ NO + [HO-V-NH2]2+ = [HO-V-NH2-NO]2+ [HO-V-NH2-NO]2+ = N2 + H2O + [VOH]2+ [VOH]2+ + 1 4 O2 = VO2+ + 1 2 H2O This reaction sequence is believed to operate during the selective catalytic reduction of NOx over vanadia-titania based catalysts. © 1990
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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