1,720,993 research outputs found
“Synthesis and characterization of optically transparent epoxy matrix nanocomposites”,
No full textIn this work optically transparent nanocomposites were prepared and characterized from an optical and
morphological point of view. An organically modified boehmite was added at different concentrations in a
diglycidyl ether of bisphenol A (DGEBA) epoxy matrix, hardened with a polyether diamine. Nanocomposites
were characterized structurally by X-ray diffraction (XRD), optically by UV–Vis–NIR spectrophotometry and
their morphology was investigated by Atomic Force Microscopy (AFM).
Morphological investigation reveals the presence of boehmite particles dispersed in the epoxy matrix in
different dimensions ranging from ten to hundreds of nanometers; some aggregation in the particles is the
tendency noticed in the AFM images. The acquisition of multiple AFM images in different areas of the sample
was used for a statistical analysis of the volumetric distribution of boehmite aggregates. The obtained result,
(3.6±0.3)%vol, is well comparable to thermogravimetric analysi
Porphyrinogen Pyrrole Macrocyclic Derivative Thin Layer for Optical Transduction Gas Sensors of Alcohol Vapours
No full textThin films of meso-octaethylporphyrinogen with different thickness were deposited on suitable substrates by Langmuir-Blodgett deposition technique in order to realize optical-sensitive active layers using Surface Plasmon Resonance (SPR) technique as transduction methodology. Analysis of the morphology of the sensing layers was performed by Atomic Force Microscopy. In particular, such coatings were tested for the detection of alcohol vapors such as ethanol, methanol and isopropanol. This
resulted in a reversible shift in the resonance depth and angular position of the SPR curves, depending on the interactions between the sensing layers and the alcohol vapor molecules. Different sensitivity and rate of response for different alcohol molecules were found and analyzed. Measurements of the sensing
response towards successive expositions of the sensing layers to methanol, ethanol and isopropanol vapors were performed in order to analyze the discrimination properties of the active layers towards the analytes
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
Thin Films of TiO2 Nanocrystals with Controlled Shape and Surface Coating for Surface Plasmon Resonance Alcohol Vapor Sensing
No full textThis work explores the potential of thin films composed of shape-controlled colloidal TiO2 nanocrystals in optical gas sensing applications. To this purpose, an optical characterization of nanocrystal thin films has been performed by means of UV–vis spectroscopy and surface plasmon resonance (SPR) technique. In particular, this technique has been used as optical transduction method to test the sensing properties of the oxide films towards alcohol vapours. Numerical fitting routines have been employed to evaluate quantitatively the changes in the characteristic optical parameters for the investigated films during the sensing process. It has been found that rod-shaped TiO2 nanocrystals provided with close-packed monolayers of long-chain surfactants on their surfaces, maximize the sensor response, as they may help to achieve a higher degree of alcohol accumulation on the active material
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
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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