1,721,006 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Výzkum a vývoj katalyzátorů na bázi platiny pro palivové články s protonově vodivou membránou
No full textRozšířené přijetí pokročilých energetických technologií, jako jsou palivové články s protonově vodivou membránou (PEMFC), závisí na vývoji účinných a odolných katalyzátorů pro reakci redukce kyslíku (ORR). Platina je první volbou, pro její jedinečné vlastnosti splňující požadavky na aktivitu. Využívá se buď ve své čisté formě nebo jako slitina na bázi Pt. Výzva však stále přetrvává kvůli degradaci katalyzátoru v nepříznivém prostředí katody PEMFC. Tato práce si klade za cíl zkoumat účinné a odolné katalyzátory pro ORR na bázi Pt připravené technikou magnetronového naprašování. V první kapitole byly systematicky studová ny slitiny Pt-Au s různými složeními (5, 10, 20 at. % Au) s cílem porozumět souvislostem mezi složením, aktivitou a stabilitou. Bylo zjištěno, že slitina Pt90Au10 projevuje nejoptimálnější vlastnosti, zachovávající aktivitu Pt a efektivně potlačující rozpouštění Pt. Stabilita slitin Pt-Au byla dále zkoumána za různých simulovaných pracovních podmínek PEMFC, což prokázalo jejich vyšší stabilitu ve srovnání s monometalický m katalyzá torem Pt. Ve druhé kapitole byl zkoumán vztah mezi složením, aktivitou, a stabilitou terciá rní ch slitin PtNi-Au s různými složeními (3, 7, 15 at.% Au, Pt:Ni = 50:50). Bylo zjištěno, že začlenění Au negativně ovlivňuje aktivitu, ale zlepšuje stabilitu. Mezi...Widespread adoption of advanced energy technologies, such as proton- exchange membrane fuel cells (PEMFCs), relies on the development of efficient and durable catalysts for oxygen reduction reaction (ORR). Given its unique properties, platinum has been the primary choice for meeting activity demands, either in its pure form or as various Pt-based alloys. The challenge yet persists with catalyst degradation in the hostile environment of the PEMFC cathode. The thesis aims to explore efficient and durable Pt-based ORR catalysts prepared by the magnetron sputtering technique. In the first chapter, Pt-Au alloys with various compositions (5, 10, 20 at.% of Au) were systematically studied to understand their composition-activity-stability relationship. It was found that Pt90Au10 exhibits the most optimal alloying, retaining the activity of Pt while effectively suppressing Pt dissolution. The stability of Pt-Au alloys was further evaluated under different simulated PEMFC operating conditions, demonstrating their higher stability compared to monometallic Pt catalyst. In the second chapter, the composition-activity-stability relationship of ternary PtNi-Au alloys with various compositions (3, 7, 15 at.% of Au, Pt:Ni = 50:50) was investigated. It was revealed that while Au incorporation negatively impacts activity, it...Department of Surface and Plasma ScienceKatedra fyziky povrchů a plazmatuMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Research and development of platinum-based cathode catalysts for proton exchange membrane fuel cells
No full textWidespread adoption of advanced energy technologies, such as proton- exchange membrane fuel cells (PEMFCs), relies on the development of efficient and durable catalysts for oxygen reduction reaction (ORR). Given its unique properties, platinum has been the primary choice for meeting activity demands, either in its pure form or as various Pt-based alloys. The challenge yet persists with catalyst degradation in the hostile environment of the PEMFC cathode. The thesis aims to explore efficient and durable Pt-based ORR catalysts prepared by the magnetron sputtering technique. In the first chapter, Pt-Au alloys with various compositions (5, 10, 20 at.% of Au) were systematically studied to understand their composition-activity-stability relationship. It was found that Pt90Au10 exhibits the most optimal alloying, retaining the activity of Pt while effectively suppressing Pt dissolution. The stability of Pt-Au alloys was further evaluated under different simulated PEMFC operating conditions, demonstrating their higher stability compared to monometallic Pt catalyst. In the second chapter, the composition-activity-stability relationship of ternary PtNi-Au alloys with various compositions (3, 7, 15 at.% of Au, Pt:Ni = 50:50) was investigated. It was revealed that while Au incorporation negatively impacts activity, it..
Variations on the Author
Get PDF“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
Get PDFWe 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
Molecular Anchoring to Oxide Surfaces in Ultrahigh Vacuum and in Aqueous Electrolytes: Phosphonic Acids on Atomically-Defined Cobalt Oxide
No full textIn this work, we investigated the interaction of phenylphosphonic acid (PPA, C6H5PO3H2) with atomically-defined Co3O4(111) thin films, grown on Ir(100), under ultrahigh vacuum (UHV) conditions and in the electrochemical environment. In the first step, we employed infrared reflection absorption spectroscopy (IRAS) and followed the formation of a saturated monolayer (380 K) in UHV. We observed that the binding motif changes from a chelating tridentate in thesub-monolayer regime to a chelating bidentate at full monolayer coverages. In the electrochemical environment, we analyzed the interaction of PPA with the same Co3O4(111) surface by electrochemical infrared reflection absorption spectroscopy (EC-IRRAS) (0.3 VRHE ? 1.3 VRHE). When adsorbed at pH 10 from an ammonia buffered aqueous solution, PPA binds to the surface in form of a fully deprotonated chelating bidentate. With increasing electrode potential, we observed two fully reversible processes. At low buffer concentration, protons are released upon oxidation of surface Co2+ ions and lead to protonation of the anchored phosphonates. At high buffer concentration, most of the protons released are accepted by NH3. Simultaneously, the surface phosphonate changes its adsorption motif from bidentate to tridentate while adopting a more upright geometry.Fil: Bertram, Manon. Universitat Erlangen-Nuremberg; AlemaniaFil: Schuschke, Christian. Universitat Erlangen-Nuremberg; AlemaniaFil: Waidhas, Fabian. Universitat Erlangen-Nuremberg; AlemaniaFil: Schwarz, Matthias. Universitat Erlangen-Nuremberg; AlemaniaFil: Hohner, Chantal. Universitat Erlangen-Nuremberg; AlemaniaFil: Montero, María de Los Angeles. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; ArgentinaFil: Brummel, Olaf. Universitat Erlangen-Nuremberg; AlemaniaFil: Libuda, Joerg. Universitat Erlangen-Nuremberg; Alemani
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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