1,721,083 research outputs found
Frequency doubling, absorption and grating deformation in glass fibres: effective defects or defective effects?
No full textThe present understanding of colour centres in germanosilicate glass fibres and the diverse effects attributed to colour centre activity are reviewed. Drawing on a wide range of up-to-date research results, an attempt is made to piece together as far as possible a unified picture of the defect processes behind second harmonic generation, nonlinear transmission and photorefractive grating formation in optical fibres
Optically induced creation, transformation and organisation of defects and color centers in optical fibres
No full textOver the past five years, a colour-centre model for the dynamics of the absorption induced in germanosilicate fibres upon exposure to blue/green light has been under development at Southampton. This model is introduced and its predictions used for the first time to test our proposed Kramers-Kronig mechanism for the concurrent refractive index changes induced in the visible and the infra-red. It is found that the predicted colour-centre population changes in the UV are to explain these refractive index changes. A possible alternative model, based on density changes in the glass triggered by colour-centre formation, is assessed experimentally and analytically. The implications of this result to photonically driven self-organisation in fibres is briefly assessed, and reference made to recent experimental results
Laser direct writing strategies for the rapid prototyping of flexible electronics
Full text linkDiode pumped solid state (DPSS) lasers have made great progress in terms of reliability
in the last two decades. When combined with CNC technologies, the unique ability of
digitally depositing a controlled amount of energy at high resolution makes DPSS lasers
the preferred tools for a vast and steadily growing number of applications across multiple
industries. Flexible electronics nowadays are predominantly served by photolithographic
manufacturing techniques. Such techniques are viable only for large volume production.
During the prototyping phase, when small and medium volume pilot production is
needed, a digital and mask free production technique such as laser direct writing can
shorten the development phase and give a competitive boost. In this work, DPSS laser
direct writing is employed for the fabrication of flexible electronic devices. Both
subtractive (laser thin film patterning, hole drilling) and additive (laser induced forward
transfer, LIFT) laser direct writing techniques were explored with pulse durations ranging
from tens nanosecond to hundreds of femtoseconds to achieve a repeatable patterning and
printing resolution up to 10 µm in an industrial environment. The emphasis was on
finding the best laser parameters to deliver optimum results for real commercial case
studies. Second, the attention focused on how to be more effective and competitive in
delivering such applications by improving both the post processing step and the hardware
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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