1,721,067 research outputs found
Influence of the dopants on the electrical resistance of hematite-based humidity sensors
No full textInfluence of the dopants and the metal electrodes on the electrical response of hematite based humidity sensors
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Hematite based humidity sensors: electrical response in function of the dopants and the nature of the electrodes
No full textStatic magnetic susceptibility, crystal field and exchange interactions in rare earth titanate pyrochlores
Full text linkThe experimental temperature dependence (T = 2–300 K) of single crystal bulk and site susceptibilities of rare earth titanate pyrochlores R2Ti2O7 (R = Sm, Eu, Gd, Tb, Dy, Ho, Er, Yb) is analyzed in the framework of crystal field theory and a mean field approximation. Analytical expressions for the site and bulk susceptibilities of the pyrochlore lattice are derived taking into account long range dipole–dipole interactions and anisotropic exchange interactions between the nearest neighbor rare earth ions. The sets of crystal field parameters and anisotropic exchange coupling constants have been determined and their variations along the lanthanide series are discussed.
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
Application of the Yb-172 PAC probe to the study of Yb atom charge states in solids
No full textWe present PAC measurements performed using the 172Yb probe in two Yb intermetallic compounds, Yb4As3 and Yb5Si3. The hyperfine quadrupole interaction was measured in a wide temperature range from 78 to 850 K. The temperature dependence of the electric field gradient differentiates divalent and trivalent Yb ions. In Yb4As3 we observe a phase transition at 295 K and a heterogenous mixed valence state in the low temperature phase. By contrast, the Yb ions in the two crystallographic sites in Yb5Si3 can be classified as trivalent Yb ions with a large crystal field interaction
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
Valence states of Yb in Yb5Si3
No full textWe have measured the quadrupole hyperfine interaction in the intermetallic compound Yb5Si3 using 170Yb Mössbauer absorption spectroscopy in the temperature range 0.03–80 K and 172Yb perturbed angular correlation spectroscopy in the temperature range 20–750 K. Data of LIII-edge x-ray absorption and magnetic susceptibility are also presented, as well as a 170Yb Mössbauer spectrum with a magnetic field of 7 T at 4.2 K. There are two distinct crystallographic sites for Yb in Yb5Si3. The whole set of our measurements shows that the two sites contain Yb ions in a charge state close to 3+, but with different hybridization strengths, making Yb5Si3 a unique compound. No magnetic ordering of the Yb3+ sublattice is shown down to a temperature of 0.03 K
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