1,720,973 research outputs found
Femtosecond pulsed laser deposition of amorphous gallium lanthanum oxysulphide films
No full textWe report femtosecond and nanosecond pulsed laser deposition (PLD) of gallium lanthanum oxysulphide (GLSO) films. Energy-dispersive X-ray analysis reveals that the atomic percentages of gallium, lanthanum and sulphur are well outside the conventional range for glass formation
Combinatorial synthesis and screening of chalcogenide materials for data storage
No full textFor more than 15 years researchers at the Optoelectronics Research Centre at the University of Southampton have been developing novel compositions of chalcogenide glasses for a wide range of optical applications. Recently this expertise has been combined with those of Ilika Technologies Ltd and the School of Chemistry to focus on the development of enhanced chalcogenide materials for OUM and optical data storage applications. In our talk, we report on our high throughput methodology which allows rapid, reproducible and comprehensive mapping of phase diagrams and screening of optical, thermal and electrical properties. These procedures were initially applied to Ge:Sb:Te compositions where we were able to synthesis and analyse over 4000 sample points spanning the entire ternary system. In order to process such large volumes of compositions, novel screening techniques and strategies have been employed. We are applying this methodology to other novel compositions and our findings are reported
High throughput synthesis and screening of chalcogenide materials for data storage
No full textThe ability to store information through the phase change mechanism is a well established technology for optical data storage, with typically germanium antimony telluride based films forming the active layer of a phase change disc. However, the ever increasing need for greater storage densities, shorter write/erase, duration and longer archival time is driving interest beyond these established materials. A new thin high throughput thin film deposition method provides a well controlled route to the synthesis of a wide range of chalcogenide compositions through simultaneous deposition of the component elements. When combined with fast primary and secondary screening techniques, the amorphous / crystalline phase transition can be characterised across the ternary compositional space. When combined with a full high throughput characterisation of the phases using EDX and XRD, conductivity measurements and ellipsometric characterisation of the optical properties, a better understanding of the desired phenomena for phase change memory applications is accessible. Results of a high throughput study of the GeSbTe system are presented
Germanium antimony sulphide nano-wires fabricated by chemical vapour deposition and e-beam lithography
No full textGermanium antimony sulphide (Ge-Sb-S) amorphous thin films have been deposited directly onto SiO-on-silicon substrates by means of chemical vapour deposition. The Ge-Sb-S films have been characterized by micro-Raman, scanning electron microscopy, energy dispersive X-ray analysis and static tester techniques. Ge-Sb-S nano wires have been patterned and fabricated by e-beam lithography and dry etching techniques. Modeling results show the potential for fast switching of these Ge-Sb-S nano wire structures, making it a possible candidate for the phase change memory applications
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
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