1,720,987 research outputs found
Metastable phase formation during the decomposition of Fe-20 at.% Mo
No full textThe early stages of the isothermal decomposition of an Fe-20 at.% Mo alloy at 500 degrees C have been studied by means of atom-probe (AP) and field-ion microscopy (FIM), as well as high-resolution (HREM) and conventional (CTEM) transmission electron microscopy. CTEM reveals a characteristic modulated structure oriented along the (100)-type directions of the b.c.c. matrix. Electron diffraction patterns show satellite-like intensities close to the fundamental reflections in (100)-type directions, indicating an approximate 6 nm characteristic length scale of the decomposition microstructure. FIM and HREM reveal precipitates about 2 nm in size with a b.c.c. structure formed coherently within the matrix. AP analyses show these precipitates to consist of almost pure Mo. The size misfit between the Mo-rich precipitates and the Fe-rich matrix causes large coherency strains, resulting in precipitate alignment along (100)-type directions. The Mo-rich b.c.c. solid solution precipitates in a metastable equilibrium with the Fe-rich b.c.c. matrix, whereas the formation of the equilibrium intermetallic phases is kinetically suppressed. A coherent metastable miscibility gap between the Fe-rich and the Mo-rich b.c.c. solid solution is assessed by incorporating a continuum elasticity strain-energy term into the Gibbs free energy. (C) 2000 Acta Metallurgica me. Published by Elsevier Science Ltd. All rights reserved
Nanocrystalline Ni-3.6 at.% P and its transformation sequence studied by atom-probe field-ion microscopy
No full textThe transformation sequence of electroless plated nanocrystalline Ni-3.6 at.% P layers upon different heat treatments is studied by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and atom-probe field-ion microscopy (APFIM). APFIM reveals P segregation at the grain boundaries in the as-plated nanocrystalline alloy. DSC shows two heat releases upon isochronic heat treatment. During the first heat release, starting at about 136 degrees C for a heating rate of 20 degrees C/min, structural relaxation occurs first, followed by slight crystal growth and segregation enhancement, as shown by XRD and APFIM. Nucleation of the equilibrium phase Ni3P starts in the transition lo the second heat release. This second heat release, with a sharp onset at 417 degrees C for heating at a rate of 20 degrees C/min, is related to the major part of Ni3P-phase formation and substantial grain growth. The transformation sequence is compared with the one observed on amorphous Ni-P alloys and discussed in terms of a thermodynamic model. (C) 2000 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All rights reserved
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
Detailed Microstructural Investigation of Oxidation Phenomena in 1144 FBS
No full textThe 1144 phase (Ae(1)A(1)Fe(4)As(4)) shows a strong advantage of engineering fabrication among Fe (Iron)-based superconductor (FBS) family due to the robustness of its superconducting properties with respect to chemical inhomogeneities, granted by its stoichiometric nature. This regularity is furthermore associated to defects capable of acting as efficient pinning centers with high critical currents achieved at high fields for these superconductors. Like other FBS phases, its lossless current-carrying capability can be remarkably degraded by distractions at grain boundaries (GBs). GB oxidation is an issue of upmost importance to the realization of the practical FBS application for high field (>20 T) magnet. In this study, we explore oxidized grain boundary and intrinsic grain structural properties of 1144 polycrystalline samples by applying analytical electron microscopy such as atomic resolution scanning transmission electron microscopy and atom probe tomography. These structural properties of 1144 samples are evaluated following the degradation of superconducting properties due to oxidation. We observe a strong correlation between the contamination at grain boundaries and the decrease of transport properties of the bulk sample, while the bulk crystalline structure is not affected by the oxidation. crystallin
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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