1,721,096 research outputs found
Laser fluence dependence on emission dynamics of ultrafast laser induced copper plasma
No full textThe characteristic emission features of a laser-produced plasma depend strongly on the laser fluence.
We investigated the spatial and temporal dynamics of neutrals and ions in a femtosecond
laser (800 nm, 40 fs, Ti:Sapphire) induced copper plasma in vacuum using both optical emission
spectroscopy (OES) and spectrally resolved two-dimensional (2D) imaging over a wide fluence
range of 0.5–77.5 J/cm2. 2D fast gated monochromatic images showed a distinct plume splitting
between the neutrals and ions, especially at moderate to higher fluence. OES studies at low to moderate
laser fluence confirm intense neutral line emission over ion emission, whereas this trend
changes at higher laser fluence with dominance of the latter. This evidences a clear change in the
physical processes involved in the femtosecond laser-matter interaction at high input laser intensity.
The obtained ion dynamics resulting from OES and spectrally resolved 2D imaging are compared
with charged particle measurement employing Faraday cup and Langmuir probe; results
showed good correlation
Direct femtosecond laser surface structuring of crystalline silicon at 400 nm
No full textWe have analyzed the effects of the laser pulse wavelength (400 nm) on femtosecond laser surface
structuring of silicon. The features of the produced surface structures are investigated as a function
of the number of pulses, N, and compared with the surface textures produced by more standard
near-infrared (800 nm) laser pulses at a similar level of excitation. Our experimental findings highlight
the importance of the light wavelength for the formation of the supra-wavelength grooves,
and, for a large number of pulses (N ~ 1000), the generation of other periodic structures (stripes) at
400 nm, which are not observed at 800 nm. These results provide interesting information on the
generation of various surface textures, addressing the effect of the laser pulse wavelength on the
generation of grooves and stripes
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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