1,720,986 research outputs found
SYNTHESIS OF PHOTOLUMINESCENT CORE-SHELL SILICA PARTICLES BY SACRIFICIAL POLYMER SHELL METHOD
No full textA novel approach has been developed for the synthesis of SiO 2@Y 2O 3:Eu 3+ particles with core-shell structure. In this method the polymer shell is obtained by copolymerization of methacryl oxyethyl isocyanate onto silica particles which are chemically modified by 3-(trimethoxysilyl) propyl methacrylate. The grafted polymer acts as template to prepare the luminescent shell on silica particles. Then, the obtained silica-polymer core-shell particles are dispersed in a solution of Yttrium and Europium nitrates to allow a physical adsorption of the ions by the polymer shell. The sacrificial polymer shell will be removed by thermal treatment to obtain photoluminescent SiO 2@Y 2O 3:Eu 3+ core-shell particles. Results reveal that the intensity of photoluminescence of these core-shell particles is much higher than intensity of particles prepared without sacrificial polymer shel
Gelcasting of Al2O3/Ag nanocomposite using water-soluble solid-salt precursor
No full textAbstract not availableMohsen Haji, Touradj Ebadzadeh, Mohamad Hassan Amin, Mahmood Kazemzad, Tahereh Taleb
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
Synthesis and Sintering of Mullite Ceramics Using Microwave Heating
No full textMullite ceramics have been known as the engineering materials due to their special properties such
as high refractoriness, good thermal shock resistance, low thermal expansion, good strength at low
and high temperatures, good creep resistance and low dielectric constant. In the present work,
mullite samples were prepared by reaction sinteing of alumina and silica gel and subsequent
sintering in a microwave process. The sintering of samples was carried out at temperatures in the
range of 1400-1500°C with no soaking time. Density and porosity measurements showed a high
density (89.3% TD) and low porosity (5.8%) for samples sintered at 1400°C under microwave
conditions while for samples sintered conventionally at this temperature after 2h heating, density
decreased (81.9% TD) and porosity increased (18.5%). By increasing sintering temperature to 1450
and 1500°C under microwave conditions, density increased (93.3 and 93.8% TD) and porosity
decreased (0.31 and 0.36%), respectively. Microhardness measurements showed 27.6% increment
when sintering temperature increased from 1400 to 1500°C. The mean grain size increased (34.8%)
for samples sintered in furnace rather than those sintered in microwave process.</jats:p
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
Synthesis of BaFe<sub>1-x</sub> Ni<sub>x</sub> Cu<sub>x</sub> O<sub>3-δ</sub> new ceramic composition as solid oxide fuel cell cathode by microwave-assisted solid-state reaction
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