1,720,960 research outputs found
Gas sensing properties of carbon nanostructures
Full text linkThis work is aimed to evaluate the optical gas sensing properties of carbon nanomaterial. In particular it is focused on two materials, Carbon Nanotubes (CNTs) and Graphene Oxide
(GO).
The comprehension of the mechanisms of interaction of these materials with the gas molecules is fundamental for a future application of these materials as sensors targeted to a
specific specie or capable to distinctly detect several dangerous species. On this purpose nanostructures based on GO and CNTs have been produced and tested as optical gas sensors toward oxidizing/reducing gases (H2, CO, NO2) and aromatic volatile Organic Compounds (benzene, toluene, xylene).
Gold nanoparticles (Au NPs) have been used as optical probe thanks to the peculiar Localized Surface Plasmon Resonance feature in the visible range, which is extremely
sensitive to the variation in optoelectronic properties of the surrounding media, such as refractive index and the variation in charge carrier involved in plasmonic excitation in the Au NPs.
Not only amplify the Au NPs the variation in optoelectronic properties of the layer of carbon nanomaterial, but also the electromagnetic coupling with carbon nanomaterials may induce
an enhancement in response and a lowering of the limit of detection of the sensors to the target species.
Moreover, the GO and CNTs are provided of a large possibility of functionalization, which can be used to tailor the gas sensing properties of the nanostructures toward specific species.
CNTs have been combined with the Au NPs, Pd NPs, Ni NPs and fullerenes. Pd and Au NPs increase the response toward H2
, meanwhile Ni NPs and fullerenes appear specific to CO. It
is also suggested the opportunity to monitor the features of the absorbance plot of fullerenes and CNT in the NIR as optical probes, with the carbon nanomaterials playing both the role
of sensing element and optical probe.
The presence of the different functional groups in GO was investigated. The increase in sp2conjugation has a profitable effect for the sensing of H2. Instead, the removal of the oxidized
functional groups hinder the response of the films toward CO and NO2.
The reduction and functionalization of the GO with para- Phenylene Diamine induces the detection of NH3without Au NPs as optical probe. The sensors produced are characterized by high transparency in the visible range and may be incorporated as non-invasive sensors on transparent surfaces.
Most of the sensors worked at 150°C and 300°C. Test of gas sensing have been conducted at low temperatures, at 80°C for CNTs in fullerene matrix and good results were achieved. The
possibility of sensors active at room temperature is suggested by the positive tests conducted with CMG, paving the way for future developments in active optical material sensitive to
gases at room temperature
Transparent carbon nanotube film as sensitive material for surface plasmon resonance based optical sensors
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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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