1,720,956 research outputs found
New experimental methods for the characterization of diffusion processes in battery electrode materials with high spatial resolution based on atomic force microscopy
No full textBatteriebasierte Energiespeicher – darunter insbesondere die Lithiumionenbatterie – stellen eine Schlüsseltechnologie zur erfolgreichen Bewältigung der Energiewende dar. Moderne Lithiumionenbatterien sind hochkomplexe, partikulär aufgebaute Systeme, deren Materialdesign ein tiefgehendes Verständnis der involvierten Transportprozesse erfordert. Bisher mangelt es an Analytikmethoden zur Untersuchung dieser Transportprozessen mit räumlicher Hochauflösung, um einzelne, nanoskopisch kleine Bestandteile einer Batterie zu charakterisieren und somit mögliche Schwachstellen exakt identifizieren zu können. In der vorliegenden Arbeit soll ein Beitrag zur Schließung dieser Lücke aufgezeigt werden. Es werden zwei neuartige Methoden zur nanoskaligen Analytik an Batteriematerialien entwickelt und vorgestellt. Beide Methoden basieren auf dem Einsatz der Rasterkraftmikroskopie. Der Fokus der Untersuchungen liegt dabei insbesondere auf der räumlich hochaufgelösten Quantifizierung der ambipolaren Diffusion in Batterie-Elektrodenmaterialien, welche einen fundamental wichtigen Transportprozess in Lithiumionenbatterien darstellt.Battery-based energy storage systems - including the lithium ion battery in particular - represent a key technology for successfully mastering the energy transition. Modern lithium ion batteries are highly complex, particulate systems whose material design requires an in-depth understanding of the transport processes involed. Until now, there has been a lack of analytical methods to investigate transport processes with high spatial resolution in order to characterize individual, nanoscopically small components of a battery and thus accurately identify potential bottlenecks. In the present work, a contribution to fill this gap is demonstrated. Two novel methods for nanoscale analysis on battery materials are developed and presented. Both methods are based on the atomic force microscopy. The focus of the investigations is in particular on the spatially high-resolution quantification of ambipolar diffusion in battery electrode materials, which is a fundamentally important transport process in lithium ion batteries
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
Cobalt- and rhodium-corrole-triphenylphosphine complexes revisited: the question of a noninnocent corrole
Get PDFA reinvestigation of cobalt-corrole-triphenylphosphine complexes has yielded an unexpectedly subtle picture of their electronic structures. UV-vis absorption spectroscopy, skeletal bond length alternations observed in X-ray structures, and broken-symmetry DFT (B3LYP) calculations suggest partial CoII-corrole•2- character for these complexes. The same probes applied to the analogous rhodium corroles evince no evidence of a noninnocent corrole. X-ray absorption spectroscopic studies showed that the Co K rising edge of Co[TPC](PPh3) (TPC = triphenylcorrole) is red-shifted by ∼1.8 eV relative to the bona fide Co(III) complexes Co[TPC](py)2 and Co[TPP](py)Cl (TPP = tetraphenylporphyrin, py = pyridine), consistent with a partial CoII-corrole•2- description for Co[TPC](PPh3). Electrochemical measurements have shown that both the Co and Rh complexes undergo two reversible oxidations and one to two irreversible reductions. In particular, the first reduction of the Rh corroles occurs at significantly more negative potentials than that of the Co corroles, reflecting significantly higher stability of the Rh(III) state relative to Co(III). Together, the results presented herein suggest that cobalt-corrole-triphenylphosphine complexes are significantly noninnocent with moderate CoII-corrole•2- character, underscoring - yet again - the ubiquity of ligand noninnocence among first-row transition metal corroles.</p
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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