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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
STRUCTURAL STUDIES OF AL-BASED POWDERS PREPARED BY CHEMICAL METHODS
No full textFinely dispersed metal powders have been obtained after chemical reduction of Ni and Co acetylacetonate by lithium aluminum hydride in tetrahydrofuran at low temperature. The Al/Ni and Al/Co stoichiometry of the as-reduced powders was 1.1 and 1.2, respectively. The structure and thermal stability of the as-reduced powders were affected by the temperature of reduction. For the NiAl powders it was found that the thermal treatment initially induces a separation of highly unstable Ni(Al) and Al(Ni) solid solutions, which subsequently react to give a single NiAl phase of cubic structure not reported in the equilibrium phase diagram. Conversely, the reduction of cobalt acetylacetonate directly gives a cubic metastable phase, from which precipitates some hexagonal form of Co after treatment at 450-degrees-C
Anelastic properties and solid state reactivity of Fe-Al nanostructured intermetallic compounds
No full textIron and Aluminium elemental powders mixed in the atomic ratio Fe50Al50 and Fe75Al25 have been alloyed using an high energy mill system. The structural transformation of the milled products has been followed using XRD techniques. Samples obtained from cold-consolidation of the milled powders have been used for Elastic Energy Dissipation measurements (IF) and analysed in the temperature range 300-980 K. The XRD spectra corresponding to specimens milled for long times reveal the formation of the FeAl and Fe3Al nanostructured intermetallic compounds. The IF spectra show two relaxational damping peaks P-1,P-2 in the temperature range 600-980 K. The peak evolution for different milling treatments indicates a Zener and a grain-boundary relaxation mechanisms for P-1 and P-2 respectively
Surface hardening of Ti-6Al-4V alloy by diffusion treatment of electroless Ni-B coatings
No full textElectroless nickel - boron coatings on Ti-6Al-4V alloy were obtained by immersion in nickel chloride aqueous solutions with both dimethylamine amine borane and sodium borohydride as reducing agents. On some samples, a graphite layer was deposited by physical vapour deposition before the electroless deposition. Heat treatments at 800° C for 40 h were performed to obtain surface hardening of the titanium alloy. The effect of different deposition agents on the depth of hardening was studied by XRD, SEM, EDS and glow discharge optical spectrometry. Surface hardness > 1000 HV and depth of hardening > 500 μm were achieved by diffusion of layers obtained with sodium borohydride as reducing agen
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
Electrochemical behaviour of Cu-Zr and Cu-Ti glassy alloys
No full textHydrogen evolution is a fundamental reaction for better understanding of electrochemical activity of electrode materials. Amorphous Cu-Zr and Cu-Ti ribbons were produced by melt spinning methods and were characterized by X-ray diffraction, scanning electron microscopy and differential scanning calorimetry. The electrocatalytic efficiency was evaluated on the basis of electrochemical data obtained from cathodic polarization curves carried out in both acid and basic medium at 25°C. The surfaces of amorphous materials were prepared, before electrochemical measurements, by immersion in HF solutions. The results were compared to those obtained on polycrystalline copper and on untreated ribbons. The HF treatment yielded a porous copper structure with a higher roughness factor which had improved electrocatalytic activity compared with that of polycrystalline copper electrode
Raman Spectra of Water in the Translational Region: Recent Interpretation of the Experimental Spectra and Comparison with MD Results
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