1,720,959 research outputs found
Detailed structure of the hexagonally packed mesostructured carbon material CMK-3
No full textDetailed investigation of the ordered mesoporous CMK-3 carbon using XRD structural modeling based on the continuous electron density representation and the Rietveld technique allowed deriving comprehensive and consistent information on the material anatomy. The electron density distribution map agrees with carbon 'bridges', which seem to be attributed to the material interconnecting carbon nanorods in the CMK-3 mesostructure. These carbon 'bridges' are supposed to be derived from former complementary mesopores of the SBA-15 template used. (C) 2002 Elsevier Science Ltd. All rights reserved.We are grateful to the INTAS Fellowship grant for Young Scientists YSF 2001/ 2-3, INTAS grant (proposal 2283) and joint grant KRSF-RFBR 02-03-97704. R. Ryoo gratefully acknowledges that this work was supported in
part by the Ministry of Science and Technology through Creative Research Initiative Program, and by School of Molecular Science through Brain Korea 21 Project
Framework characterization of mesostructured carbon CMK-1 by X-ray powder diffraction and electron microscopy
No full textThe model of structure and structural transformation of the mesostructured carbon material CMK-1 was established by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) investigations. The investigations showed that the enantiomeric carbon subframeworks formed within the pores of the MCM48 mesoporous template used for the material synthesis displaced with respect to one another without significant distortions after the dissolution of the silica wall of the template. The model proposed agrees well with TEM images observed. The XRD structural modeling of CMK- I done using the continuous density function technique allowed perfect fit of the calculated to the experimental powder diffraction pattern and provided geometric characteristics of the material texture. The structural characteristics obtained agreed fairly well with TEM analysis and with previously reported adsorption data.This work is supported by INTAS
Fellowship grant for Young Scientists YSF 2001/2-3, INTAS grant 01-2283, and joint Grant KRSF-RFBR 02-03-97704
Characterization of mesoporous carbons synthesized with SBA-16 silica template
No full textThe structure of ordered mesoporous carbons (OMC) synthesized with sucrose, furfuryl alcohol or acenaphthene using the SBA-16 mesoporous silica template with cubic Im (3) over barm structure has been investigated with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and N(2) adsorption. This work shows that, in contrast to carbons prepared from sucrose by using SBA-15 silica as template, the impregnation of SBA-16 with sucrose failed to produce OMC with cubic Im (3) over barm structure. However, when furfuryl alcohol and acenaphthene were used as carbon precursors, the cubic Im (3) over barm structure was retained in the products. Thus, the latter carbon precursors were more suitable than sucrose for the formation of rigidly interconnected carbon bridges through narrow apertures of the cage-like siliceous SBA-16 mesostructure. In particular, the use of furfuryl alcohol as carbon precursor allowed us to control the degree of mesopore filling in SBA-16 and consequently, to synthesize hollow or fully filled cage-like silica-carbon mesostructures as was done in the case of channel-like SBA-15. In the case of acenaphthene only fully filled mesostructures were formed but with a much higher degree of graphitization. In the present work, we took advantage of the recent developments in the synthesis of SBA-16 with tailored diameter and entrance size of mesopores and made a step forward in the fabrication of OMC by using cage-like mesoporous silicas with narrow interconnections as templates.This work was supported in part by the donors of the Creative Research Initiative Program of the Korean Ministry of Science
and Technology (R.R.), School of Molecular Science through the Brain Korea 21 project (R.R.), NSF Grant CHE-0093707 (M.J.), RFBR Grant 03-03-32127 (L.A.S.), the Swedish
Research Council (O.T.), and Sweden and Japan Science and Technology Agency, Japan (O.T.)
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
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
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