1,721,139 research outputs found
PREPARATION AND CHARACTERIZATION OF LI-DOPED ZNO FILMS
No full textZnO:Li films have been prepared by radio frequency (rf) diode sputtering using a Li-doped ZnO target. The film depositions were performed in pure Ar or in 28% O2/Ar sputtering gas. For comparison undoped ZnO films were also prepared. Structural, electrical, and optical measurements have been performed on films prepared under different deposition conditions and the results related with Li content and O/Zn ratio obtained by nuclear reaction and Rutherford backscattering measurements, respectively. The Li doping has not changed the films c-axis preferential orientation typical of the undoped films, but it introduces a crystallite order change. As is expected by deposition of doped oxides the sputtering gas mixture is the main parameter controlling the dopant concentration. Moreover, the oxygen presence in gas mixture has also been found to play an important role in controlling the optical properties of the film. The change in lithium concentration does not affect the electrical resistivity if the deposition parameter values have been selected in order to produce undoped zinc oxide films with a high electrical resistivity
Copper-based nanocluster composite silica films by rf-sputtering deposition
No full textPrescribed nanocluster composite glass features require the control of the cluster formation and growth, and therefore the definition of effective preparation protocols. In this work, copper-containing silica films were synthesized by sputtering co-deposition of copper and silica in a radiofrequency magnetron sputtering apparatus. The composite system was sequentially thermally-treated in different annealing environment (oxidizing and/or reducing). Characterization of samples along the various preparation steps was performed by Rutherford backscattering spectrometry, X-ray diffraction, and optical absorption spectroscopy. The copper behavior during the composite formation was complex: copper migration and aggregation depend critically on the annealing conditions, and quite different stable structures actually result, such as fcc Cu and/or monoclinic CuO nanoparticles
DUAL-ION-BEAM SPUTTER DEPOSITION OF TIN FILMS
No full textA dual-ion-beam technique for the deposition of TiN thin films is described. The metal-atom flux is supplied by sputtering a titanium target with an inert ion beam, while the reactive flux is supplied directly to the growing film by a low-energy ion beam. Results are presented for titanium films deposited at room temperature under a range of N2+ ion bombardment to form TiN. Analysis gives the incorporation of nitrogen, the background gas contamination, and the optical and electrical properties of TiN films
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
SOME STRUCTURAL AND OPTICAL PROPERTIES OF COPPER AND COPPER OXIDE NANOPARTICLES IN SILICA FILMS FORMED BY CO-DEPOSITION OF COPPER AND SILICA
No full textSilica films containing metal particles in the nanometer size range exhibit optical properties that make them useful in several applications. In this work, copper-containing silica films were synthesized by a radiofrequency magnetron sputtering co-deposition technique, and then thermally-treated (in some cases sequentially) in different annealing atmospheres, i.e. either oxidizing or reducing (700-900 °C of temperature range, 2-5 h of time range, 400 °C/h of heating rate and 250 °C/h of cooling rate). Depending on the thermal treatment, the crystallite average surface-weighted dimension ranges between 5 and 9 nm for metal copper, and is larger than 25 nm for CuO. The preparation protocols to obtain these characteristics were determined in order to control cluster formation and growth. Characterization of the samples following the various preparation steps was performed by Rutherford backscattering spectrometry, optical absorption spectroscopy, and X-ray diffraction. Our experimental observations showed that the composite formation was a function of the annealing conditions
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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