1,721,054 research outputs found
Surface science studies of rhodium gen-dicarbonyl on TiO₂(110) using FT-RAIRS and XPS
No full textReactions of the rhodium gem-dicarbonyl species, Rh(CO)2, deposited by MOCVD, on TiO2(110) have been studied under UHV conditions using FT-RAIRS, XPS and LEED. The application of FT-RAIRS to the structural characterization of absorbates on semiconductors and insulators has been developed. The alignment of surface species on TiO2(110) has been established, for the first time, through the coupling of the tangential component of the p-polarized radiation, or the parallel component of the s-polarized radiation, to vibrational modes with parallel surface components. Coupling of this mode results in an azimuthal dependence of the band intensity.P-polarized and s-polarized FT-RAIRS have been used to look at the variation of the intensity of the absorption band due to the Rh(CO)2 asymmetric stretch (ν=2030cm-1) as a function of azimuthal angle. The Rh(CO)2 unit has been found to be aligned in the <11̅;0> direction of the surface, P-polarized FT-RAIRS has also been used to study the adsorption of formic acid onto the TiO2(110) surface. Azimuthal variation of the infrared bands (ν~1550, ~1380cm-1) due to adsorbed formate has identified two formate species on the surface. One species is absorbed aligned in the <001> direction and bridging two five-fold Ti4+ sites. The other is aligned perpendicular to this and is assigned to a formate bridging between one Ti4+ site and a defect (that is produced on adsorption of formic acid) in a bridging oxygen row. Further, complementary, structural studies of Rh(CO)2 are reported using the NIXSW technique at Daresbury Laboratories.Several reactions of the Rh(CO)2 species have also been studied. For the reaction of Rh(CO)2 with H2 two steps have been identified. In the first step, which occurs at 300K and requires predissociation of H2, one O molecule is displaced leading to an intermediate RhH(CO) species (ν=2065cm-1) on highly dispersed rhodium. In the second step partial disproportionation of the remaining CO occurs to give carbidic carbon and reduced rhodium on the surface. The second step is activated on increasing the temperature, and this is proposed to be mediated by the production of defects on the TiO2(110) surface, which aid the CO dissociation reaction.Reaction of NO with the Rh(CO)2 species occurs to give a Rh(NO+) species (ν=1920cm-1) on a highly dispersed rhodium site. This reaction has been shown to be reversible and complete regeneration of Rh(CO)2 occurs on exposure of the Rh(NO+) to CO.The Rh(CO)2 species has also been found to undergo a reversible reaction with O2 to give a highly dispersed and oxidised rhodium species. This species has been assigned RhO2.Both MeI and MeCl have been shoen to dissociatively absorb on rhodium particles deposited as Rh(CO)2 at 300K, but MeCl requires the carbonyl groups to be thermally desorbed before it will absorb. Decomposition of CH3 fragments and desorption of both HI and HCl from the surface have been proposed.</p
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Sound radiation from a flanged inclined duct
No full textA simple method to calculate sound radiation from a flanged inclined duct is presented. An inclined annular duct is terminated by a rigid vertical plane. The duct termination is representative of a scarfed exit. The concept of a scarfed duct has been examined in turbofan aero-engines as a means to, potentially, shield a portion of the radiated sound from being transmitted directly to the ground. The sound field inside the annular duct is expressed in terms of spinning modes. Exterior to the duct, the radiated sound field owing to each mode can be expressed in terms of its directivity pattern, which is found by evaluating an appropriate form of Rayleigh's integral. The asymmetry is shown to affect the amplitude of the principal lobe of the directivity pattern, and to alter the proportion of the sound power radiated up or down. The methodology detailed in this article provides a simple engineering approach to investigate the sound radiation for a three-dimensional problem
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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