1,720,984 research outputs found
Determination of electric field distributions in superconductors via magneto-optical imaging and the Faraday law
No full textMagneto-optical investigation of bi-crystalline thin films of Y-123
No full textWe have performed a deliberate study on the transport properties of Y-123 thin films on bi-crystalline substrates containing low angle grain boundaries (LAGBs). By magneto-optical (MO) imaging we are able to map the magnetic field and current distribution of wide current bridges. A quantitative analysis of the distribution of currents over the entire grain boundary (GB) is presented. We discuss the effects of magnetic history on the transport properties of Y-123 thin films with LAGBs. The results are compared with artificially created two-dimensional (2D) current distributions. (C) 2004 Elsevier B.V. All rights reserved
Scanning tunneling spectroscopy of optimally doped and underdoped YBa2Cu3Ox thin films
No full textRecently, experimental and theoretical evidence was given that grain boundaries in cuprate high-temperature superconductors are charge carrier depleted zones. In order to examine, if a charge carrier reduction in YBa2Cu3Ox (YBCO) thin films is detectable by scanning tunneling spectroscopy (STS), we extensively studied optimally doped and underdoped (charge carrier reduced) YBCO films on SrTiO3 substrates. The current-voltage (I-U) characteristics of these pulsed laser deposited YBCO films were recorded by means of STS at growth island plateaus in an ultra-high vacuum (UHV). The outcome of our experiments shows that dI/dU spectra of optimally doped and underdoped films differ significantly. Since even in UHV the YBCO surface degrades, the influence of a degraded surface layer on the tunnel process is studied. It is discussed, to what extent the dI/dU spectra and the changes on doping, respectively, are related to the local density of states of the films. (C) 2002 Elsevier Science B.V. All rights reserved
born v
No full textborn vMy grandmother and her mother before her had been 'borning' babies as far back as any could remember. \ onePRINTED ITEM DNE Sup[Add to DNE born v, to 1972 cite]G. M. Story MAR. 20 1988 WKUsed I and SupUsed I and SupUsed Su
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
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
- …
