1,720,992 research outputs found
Test pattern for dielectric properties of thin films at microwave frequencies
No full textThe evaluation of the dielectric properties of ferroelectric thin films, at high frequencies, is relevant because they are goo candidates for phase and frequency agile microwave components which are used in circuits such as phase shifters, filters, and local oscillators. Recently, some measuring procedures and main expressions for general analytical formula used in the determination of the dielectric properties of thin films at microwave have been presented.
This work describes the methods that involve coplanar waveguide probes (CPW). A finite element analysis has been made on Metal-Insulator-Metal test structure to calculate some parasitic elements that cannot be estimated from measured data. A comparison between different measuments methods is presented
Influence of temperature and crystallization atmosphere on electrical parameters of lead zirconate titanate thin films
No full text
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
Nanocrystalline FeNbCuSiB Magnetic Alloys Obtained by Ball Milling
No full textWe report the obtention of nanocrystalline FeSi alloys together with an amorphous phase by direct mechanical alloying of the constituents. Powders of the pure elements in the appropriate proportions (Fe73.5Nb3Cu1Si13.5B9 and Fe73.5Nb3Cu1Si16.5B6), were mixed in a Reitch planetary ball mill for up to 120 hours. The resulting products were analyzed by X-ray diffraction and magnetic measurements. In all the cases an FeSi crystalline phase was present after a few hours of milling. Also an amorphous alloy develops simultaneously. The composition and size of the crystalline phases as well as the amount of the amorphous phase evolves during the milling. The evolution of coercive force, magnetic moment and the Curie temperature of the FeSi phase has been monitored. The coercive force decreases with increase milling time, but never reaches the low values of nanocrystalline materials obtained by heating metallic glasses of the same composition
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