1,720,955 research outputs found
In situ atomic force microscopy studies on lithium (de)intercalation-induced morphology changes in LixCoO2 micro-machined thin film electrodes
No full textStructural instability due to intercalation-induced stresses in electrode materials is one of the key degradation mechanisms of Li-ion batteries. Fragmentation of material degrades structural integrity and electrical resistance, and also accelerates harmful side reactions. In situ experiments are the appropriate approach for investigating the actual time-dependent nature of the behavior changes of an electrode material while it is charged and discharged. In the current work, a unique in situ electrochemical atomic force microscopy (ECAFM) measurement is made on samples of cylindrical shape, which are micro-machined by focused ion beam (FIB) microscopy. This pre-defined geometry allows the exclusion of secondary, non-active materials from the electrochemically active material as well as the removal of any vagueness owing from the irregular geometry of particles. The experimental results are also used to validate a proposed coupled electrochemical and mechanical model for determining the stress-strain state of active electrode material during electrochemical cycling. The results produced using this model correlate strongly with the experimental data. The combined results reveal the key effects of the geometry, kinetics, and mechanics of electrode materials on the stress-strain state, which acts as a barometer of the structural stability of a material. (c) 2012 Elsevier B.V. All rights reserved.
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
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
Metal complexes of cyanoimidazolates: Synthesis and characterization.
No full textTwo cyanoimidazoles, 4-cyanoimidazole (HMCI) and 2-(2'-pyridyl)-4,5dicyanoimidazole (HDCIPy) have been synthesized and their coordination chemistry examined. The crystal structure of 4-cyanoimidazole was observed for the first time [Pc (a = 5.7230(13) A, b = 3.6965(9) A, c = 10.244(2) A and beta = 97.689(7)°)]. The solid state structure was observed to have a net dipole moment. 4-cyanoimidazole binds metals exclusively as the anionic species and most often acts as an exobidentate bridge, generating polymers of the formula [M2+(MCl)2]n • X H2O. Thermal characterization and magnetic susceptibility studies were conducted on materials with M = Co2+, Ni 2+. Similar products and data were obtained when 4,5-dicyanoimidazolate was employed as the ligand. Single crystal X-ray diffraction was performed on the compound (Bu4N)4 Ni(MCI)6 • 2H 2O, the first hexakis imidazolate compound reported [P2(1)/c (a = 14.9380(18) A, b = 21.368(3) A, c = 16.926(2) A and beta = 115.863(2)°)]. Nine compounds containing vanadium, ruthenium, cobalt, nickel, palladium, copper or zinc ligated by DCIPy- were synthesized and characterized. Six structures, Co(DCIPy)3 • 3EtOAc [P-1 (a = 10.775(4) A, b = 14.519(5) A, c 15.732(6) A and alpha = 65.543(5)°, beta = 85.106(6)°, gamma = 84.408(6)°)], HDCIPyZn(DCIPy) 2 • MeOH [P21/n (a = 9.5538(12) A, b = 17.508(2) A, c = 18.436(2) A and beta = 95.210(2)°)], (MeOH) 2Ni(DCIPy)2 • 2 MeOH [P1 (a = 9.755(5) A, b = 11.462(7) A, c = 14.861(8) A and alpha = 70.262(16)°, beta = 83.885(17)°, gamma = 65.313(16)°)], (H2O)VO(DCIPy) 2 • 2 MeOH [P21/n (a = 11.6017(9) A, b = 17.9435(13) A, c = 12.0775(9) A and beta = 102.7430(10)°)], (H 2O)Cu2+(DCIPy)2 [P21/n (a = 7.296(3) A, b = 19.994(8) A, c = 13.014(5) A and beta = 92.640(9)°)], [P(C6H5)3]2CuI(DCIPy) [P21/n (a = 12.8981(6) A, b = 19.9043(10) A, c = 15.1140(7) A and beta = 90.3580(10)°)], were determined by single crystal X-ray diffraction. Both Co(DCIPy)3 and (bpy)2Ru(DCIPy)Cl have been tested for application in dye sensitized solar cells and have shown sufficient promise to warrant further evaluation. (H2O)VO(DCIPy) 2 has shown itself to be an effective human spermicide, affecting both motility and viability of the cell.PhDInorganic chemistryPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/125140/2/3186685.pd
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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