1,720,995 research outputs found
CONDUCTION PROCESSES IN THE LAYERED SEMICONDUCTOR COMPOUND FEPS3
No full textWe have measured, as a function of temperature, the thermopower, the dc conductivity, and photoconductivity of FePS3 single crystals. For temperatures below 430 K the thermopower shows an activated behavior, whereas at higher temperatures it is almost temperature independent. The dc dark conductivity and photoconductivity are thermally activated over the entire investigated temperature range. Moreover, ac-conductivity measurements have been carried out as a function of both temperature and frequency from 400 Hz to 100 kHz in the 340 "500-K temperature region. The transport mechanisms involved in different temperature ranges have been identified. The results have been interpreted on the basis of a simplified energy-band scheme. © 1990 The American Physical Society
Apertureless near-field optical microscopy
No full textThe physical principles of apertureless scanning near-field optical microscopy (SNOM) are analyzed. The related measurement methods for the obtainment of best resolution performance and artefact suppression are discussed. Exploiting SERS and MEF effects, locally induced by the tip, a-SNOM allows for nanometer scale chemical discrimination based on fluorescence and Raman scattering with unprecedented high sensitivity. The possibility to access the non-linearity regime at the nanoscale, is direct consequence of the development of a-SNOM techniques, which has direct implications both in two-photons photoluminescence (PL) imaging and in near-field optical lithography (NFOL)
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
Optical Near-Field Harmonic Demodulation in Apertureless Microscopy
No full textSpatial derivatives of the optical fields scattered by a surface can be investigated by apertureless near-field optical microscopy by modulating sinusoidally the probe to sample distance and detecting the optical signal at the first and higher harmonics. Demodulation up to the fifth harmonic order has been accomplished on a sample of close-packed latex spheres by means of the silicon tip of a scanning interference apertureless microscope. The working principles of such microscope are reviewed. The experimental configuration used comprises a tuning-fork-based tapping-mode atomic force microscope for the distance stabilization, and a double-modulation technique for complete separation of the topography tracking from the optical detection. Simple modelling provides first indications for the interpretation of experimental data. The technique described here provides either artefact-free near-field optical imaging, or detailed information on the structure of the near fields scattered by a surface
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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