1,720,969 research outputs found
Different measurements for thermal comfort evaluation of fabrics with anti-allergic properties
No full textWettability, a prominent comfort factor in the development of fabrics with anti-allergic properties
No full text
Formation of optically active oxygen deficient centers in Ge-doped SiO2 by gamma- and beta-ray irradiation
No full textWe report an experimental study on the comparison between the c- or b-ray induced Ge related point
defects in Ge-doped silica. Silica samples doped with 2.2 1017 Ge atoms/cm3 produced with the
sol–gel technique have been irradiated with c-ray or with b-ray. The effects of the irradiation have been
investigated by optical absorption, photoluminescence and electron paramagnetic resonance spectroscopy
in order to evaluate the generation and the dependence on dose of the Ge(1), E’Ge, GLPC (Germanium
lone pair center) and H(II) point defects. No relevant differences between the concentrations of
c- or b-ray induced Ge(1) and E’Ge point defects have been observed and, in addition, it has been found
that both irradiations are able to induce GLPC with the same dose dependence. By contrast, the main difference
regards the formation of H(II) centers, their concentration being larger after c irradiation. It is
suggested that the larger efficiency of H(II) generation is due to the specific mechanism involving H
released by irradiation, whereas the similarity of the formation of other Ge related defects speaks for
the occurrence of identical mechanisms induced by c or b irradiation
Structure of Amorphous SiO2 Nanoparticles Probed through the E'_gamma Centers
No full textWe report an experimental investigation by electron
paramagnetic resonance (EPR) spectroscopy on the properties
of the E'γ centers induced by β-ray irradiation in
nanoparticles of amorphous SiO2 (fumed silica) with mean
diameters from 7 up to 40 nm. We found that the E'γ centers
are induced in all the fumed silica types in the dose range 4-400
kGy. They are characterized by an EPR line shape similar to that
observed in common bulk silica materials independently on the
particle diameter. Moreover, the E'γ center concentration
decreases on decreasing of the particle size for each given dose.
Our findings are interpreted in terms of a shell-like model of nanoparticles in which it is assumed that stable E'γ centers can be mainly
induced in the inner part of the particles, whereas those induced in the surface shell are supposed to be essentially unstable and
rapidly disappear after irradiation. Furthermore, we have found that the same shell-like model naturally explains the actual radiation
resistance observed for nanoparticles which has been previously tentatively attributed to the high O2 content of the materials
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
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