1,721,379 research outputs found
Composite polymeric films with photocatalytic properties
No full textPolymeric films and in particular polypropylene (PP) films could be selected as excellent substrates for photocatalytic applications based on TiO2. However, hydrophobic surface of PP makes very difficult the adhesion of TiO2 particles on its surface. In this work corona pre-Treated PP was used as a support for commercial TiO2 in order to remove organic dye methylene blue (MB) from aqueous solution under UV irradiation. In details, the pre-Treated polypropylene PP films were coated with TiO2 particles by dip-coating technique. The corona pre-Treatment is a practical and effective method to increase the wettability of organic polymers due to the introduction of negative groups (COO-,-O-O-) onto the surfaces, which results in a better adhesion of the photocatalyst. The obtained coated films were characterized with different techniques sand the photocatalytic effect under UV light was analyzed in the degradation of MB dye. The photocatalytic tests were carried out in a batch photoreactor irradiated by a UV lamp (nominal power of 8 W and wavelength emission 365 nm). The experimental results showed that the coating of TiO2 onto PP films allowed to achieve a MB discoloration of 47% after about 180 min of UV irradiation. In contrast the unfunctionalized PP film did not shown any photocatalytic activity under the same irradiation conditions
Femtosecond laser surface structuring of silicon in dynamic irradiation conditions
No full textThe process of surface structuring of silicon in dynamic irradiation conditions is investigated by analyzing the
features of the surface structures generated on a target moving at different scanning velocities under the irradiation
by a 1030 nm femtosecond laser beam. Scanning electron microscopy analysis of the shallow linear
craters produced in different experimental conditions allows characterizing the dependence of threshold fluence
for the formation of surface structures (ripples and grooves) as well as their spatial periods on the effective
number of laser pulses. Moreover, the effect of the accumulated laser fluence dose has been also addressed. Our
findings evidence clear trends of the morphological features of the surface structure on the effective number of
laser pulses as well as the existence of interesting differences in their characteristics when processing occurs at
the same value of the accumulated laser fluence dose achieved by appropriate selection of laser pulse energy and
scanning speed
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
Floating zone growth of eutectic Srn+1RunO 3n+1 crystals
No full textA novel route to engineer Sr2RuO4/Sr 3Ru2O7 and Sr3Ru2O 7/Sr4Ru3O10 natural junctions has been successfully pursued by eutectic solidification in a double-mirror optical floating zone furnace in the flux feeding floating zone configuration with Ru self-flux. The synthesis procedure of the polycrystalline rod is found to be a critical factor for the crystal growth. Both eutectic systems grow in the [100] direction and cleave in the a -b plane as the single phase crystals. Extensive XRD and SEM studies show that the nature of the eutectic solidification enables the displacement of the two phases in an ordered lamellar pattern piling up along the crystallographic c-axis. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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
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