1,721,133 research outputs found
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
Synthesis, structural studies and ligand influence on the stability of aryl-NHC stabilised trimethylaluminium complexes
No full textMicrostructural characterization of MoO3-TiO2 nanocomposite thin films for gas sensing
No full textThis paper focuses on the microstructural characterization of the MoO3-TiO2 nanocomposite thin films prepared by the sol-gel process. The MoO3-TiO2 thin films were prepared by Mo(OC2H5)(5) and Ti(OC4H9)(4) precursor solutions. Different atomic ratios of the two compounds were investigated. The thin films were deposited on silicon, quartz and sapphire substrates annealed at temperatures of 400, 450, 500 and 600 degreesC for 1 h. The XRD patterns revealed the structure of the molybdenum dominated films consisted mainly of an orthorhombic MoO3 phase with preferential orientation along the (0 1 0)plane. The TEM selected area diffraction patterns revealed the presence of orthorhombic MoO3 and anatase and brookite TiO2 phases. The XPS characterization indicated the films are stoichiometric (MoO3 and TiO2). The SEM analysis showed that the films annealed at 400 degreesC are smooth and uniform with 20-100 nm sized grains. The MoO3 dominated films annealed at high temperatures (T > 500 degreesC) have relatively large micrometer particles grown out of the film. The AFM images showed that the MoO3 dominated thin films possess a high surface roughness and the TiO2 dominated films have smooth and uniform nanosized grains. The TEM results showed that the TiO2 dominated films have an average grain size of 6 nm with a narrow distribution. The MoO3 dominated films have an average size of 5 nm but with a broad distribution. The morphological and physical properties of the MoO3-TiO2 nanocomposite can be tailored by altering the ratio of the two compounds. and hence, enhanced thin films for gas-sensing could be achieved. (C) 2001 Elsevier Science B.V. All rights reserved. RI li , yongxiang/C-5059-200
Investigation of sol-gel prepared CeO2-TiO2 thin films for oxygen gas sensing
No full textThe oxygen gas sensing performance of semiconducting CeO2-TiO2 thin films have been investigated. These thin films have been prepared by the sol-gel process utilizing a non-alkoxide as the main precursors. For gas sensing measurements, the films were deposited by the spin coating technique onto alumina substrates with interdigital transducers located on the top and a micro-heater on the bottom. For the microstructural characterization, the thin films were deposited onto single crystal silicon substrates. X-ray photoelectron spectroscopy (XPS), Auger electron spectrometry (AES) and scanning electron microscopy (SEM) were employed to analyze the films. These films were exposed to various concentrations of O2 gas and their electrical responses were measured. (C) 2003 Elsevier B.V. All rights reserved
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
Comparison of single and binary oxide MoO3, TiO2 and WO3 sol-gel gas sensors
No full textA systematic comparison of sol-gel prepared titanium dioxide (TiO2), WO3, and MoO3 single metal oxide based gas sensors was conducted. Process variables such as solution concentration, deposition parameters, gelling time, annealing time and temperature, remained constant. Sensors based on binary compound MoO3-TiO2 and MoO3-WO3 were also investigated to determine if the performance is superior to their single oxide constituents. The sensors were systematically exposed to O-2, O-3, CO and NO2 gases and ethanol vapor at concentration levels of particular interest. MoO3 binary compound based sensors showed promising O-3, CO and NO2 gas response. Their use as a sensing film for gas is limited due to the materials low evaporating temperature, limiting its operating temperature below 350 degreesC. However, the binary oxide of MoO3-WO3 showed a high response to ethanol vapor and a highly selective response to NO2. (C) 2002 Elsevier Science B.V. All rights reserved
Microstructure characterization of sol-gel prepared MoO3-TiO2 thin films for oxygen gas sensors
No full textBinary metal-oxide MoO3-TiO2 films have been prepared using the sol-gel technique. The thin films were annealed at several temperatures including 400, 450, 500, 550, and 600 degreesC for 1 h. The morphology, crystalline structure, and chemical composition of the films have been analyzed using scanning electron microscopy (SEM) and atomic force microscopy, x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), and x-ray photoelectron spectroscopy (XPS) techniques. The SEM analysis showed that there are two different sizes of grains in the films annealed at temperatures of 400, 450, 500, and 550 degreesC. One grain type is small with 20-100 nm; the other is a large grain type several micrometers in length. The XRD analysis revealed that the films annealed at 400 degreesC were a mixture of orthorhombic and hexagonal MoO3 phases. The films annealed at 450 degreesC showed an increase in the hexagonal phase. A preferential orientation growth along the (100) plane of the hexagonal phase and the (010) plane of the orthorhombic phase has been found in both samples. RES and XPS analysis showed that the films were stoichiometric. When the annealing temperature was increased beyond 500 degreesC, the concentration ratio of MoO3-TiO2 decreased due to the evaporation of MoO3. For the study of the electrical and gas sensing properties, the films were deposited on sapphire substrates with interdigital electrodes on the frontside and a Pt heater on the backside. The MoO3-TiO2 thin films are sensitive to oxygen gas. The film has exhibited the O-2 response (S = R-g/R-b) of 2.1, 8.1 and 80 for 120, 1000, and 10000 ppm concentration of O-2, respectively. (C) 2001 American Vacuum Society. RI li , yongxiang/C-5059-2009; Russo, Salvy/E-5837-201
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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