1,721,039 research outputs found
Shock wave study of the unimolecular dissociation of H2O2 in its falloff range and of its secondary reactions
No full textThe thermal decomposition of H2O2 was studied behind reflected shock waves using absorption spectroscopy at 215 nm with light from a laser source and at 215, 230, and 290 nm with light from a UV lamp. Due to the improved detection sensitivity for H2O2 and HO2, rate constants for the reactions H2O2 (+Ar) --> 2HO (+Ar) (1), HO2 + HO2 --> H2O2 + O-2 (3) and HO + HO2 --> H2O + O-2 (4) could be derived with much better precision than possible in earlier work. Rate constant minima for reactions (3) and (4) near 800 and 1100 K, respectively, were reconfirmed. Fallo curves of reaction ( 1) near to the low pressure limit were measured in experiments at about 1, 4, and 15 bar. Limiting low pressure rate constants for reaction (1) of about k(1,0) = [Ar]10(16.36+/-0.23)exp [-21 962(+/-608) K/T] cm(3) mol(-1) s(-1) were obtained over the temperature range 950 1250 K. The deviations from the low pressure limit at relatively low pressures may provide experimental evidence for non-exponential lifetime distributions of dissociative H2O2 such as recently observed in classical trajectory calculations on the ab initio potential of H2O2
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
Resonant double-grating waveguide structures as inverted Fabry-Perot interferometers
No full textA multiple-interference model to describe double-grating waveguide structures is presented. It is based on the multiple-interference model for single-grating waveguide structures previously established by Friesem and co-workers [J. Opt. Soc. Am. A 14, 2985 (1997)]. We show that double grating waveguide structures, in particular, as well as the usual single-grating waveguide structures can be completely described by our model and that explicit dependences of the resonant conditions on the wavelength, the angle, and the polarization of the incident light as well as on system parameters such as refractive indices, layer thickness, grating depths, and grating period can be given. This multiple-interference model elucidates the resonance behavior of single- and double-grating waveguide structures and predicts reflection and transmission resonance bandwidths in analogy to those of the classic Fabry-Perot interferometer. One can explain and understand the periodicity of resonances by interpreting grating waveguide structures as inverted Fabry-Perot interferometers. Comparison with exact numerical calculations and verification by experimental investigations prove the model to be a powerful tool for design purposes and to provide a deep understanding of the observed resonance phenomena. (C) 2004 Optical Society of America
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
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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