1,720,954 research outputs found
Light emission from silicon/gold nanoparticle systems
No full textPhotoluminescent nanostructured semiconductor/metal systems consisting of silicon nanocrystals and gold nanoparticles are obtained by gold-catalyzed chemical etching. The interplay between silicon and gold nanostructures is investigated by photoluminescence spectroscopy upon continuous and pulsed excitation, both at room and low temperature. Comparison with reference samples, obtained removing gold particles by selective etching, highlights an enhanced emission in samples containing silicon and gold nanoparticles, explained in terms of both surface modifications and optical coupling between emitting nanocrystals and nanoparticles featuring localized plasmon resonances. (C) 2010 American Institute of Physics. [doi:10.1063/1.3483617
Chemi-Transistor Sensors based on Composite Silicon/Gold Nanostructures Prepared by Metal Assisted Etching
No full textThe ability to fabricate micro [1] and nanostructures [2] on silicon (Si) with the possibility to dope the final porous structures with noble metal NPs (e.g. gold, silver), using Metal-Assisted Etching (MAE)[3] is a unique advantage of MAE as to sensing applications. Over the standard fabrication technique such as anodic etching [4], MAE represents a low-cost room-temperature method for the synthesis of Si-based nanomaterials with peculiar sensing features, in terms of sensitivity and selectivity, towards specific gases, by bringing the catalytic properties and distinctive selectivity of the metals nanoparticles[5] and the widely tunable bandgap of the porous silicon into play.
Here the prospect of using composite silicon/gold nanostructures (cSiAuN) prepared by MAE, gold-assisted, as highly sensitive material for adsorption of Nitrogen Dioxide (NO2) is proposed, examining the controllable high-yield integration of the material into solid-state devices.
The controllable fabrication of the final nanostructures achieved by MAE approach leads to the fabrication of cSiAuN with high degree of control in terms of morphology of the pores and depth of the matrix, with enhanced sensing capabilities, which justifies their successful application in the preparation of chemi-transistor sensors, such as field-effect transistors, FETs, to be employed for gas sensing applications. As a case-of-study, we investigate the effective method for controllable integration of composite cSiAuN between electrodes of junction-field-effect transistors (JFET), aimed at the detection of NO2 down to 100 parts-per-billion (ppb). The resulting chemi-transistor sensor, cSiAuJFET (Composite Silicon Gold JFET), consists of a p-channel JFET in which the cSiAuN material is placed on top of the p-channel and acts as an extra floating gate and are responsible for the sensing capability of the JFET device. The cSiAuJFET sensors operate at room temperature and shows fast and reliable response to NO2 in the range 100-500 ppb without significant aging effects, in terms of baseline drift, response times, and sensitivity value, up to two days of continuous operation. The achieved approach presented in this work represent a guide for the possibility of employing MAE for gas sensing applications.
[1] A. G. F. Owen J. Hildreth, Ching Ping Wong, ACSNano 2012, 6, 9.
[2] L. Boarino, D. Imbraguglio, E. Enrico, N. De Leo, F. Celegato, P. Tiberto, N. Pugno, G. Amato, physica status solidi (a) 2011, 208, 1412.
[3] Peng K. Q. et al. Advanced Materials 2002, 14, 1164.
[4] G. M. Lazzerini, L. M. Strambini, G. Barillaro, Sci Rep 2013, 3, 1161.
[5] L. C. Nicola Cioffi, Eliana Ieva, Rosa Pilolli, Nicoletta Ditaranto, Maria Daniela Angione, Serafina Cotrone, Kristina Buchholt, Anita Lloyd Spetz, Luigia Sabbatini, Luisa Torsi, Electrochimica Acta 2011, 56
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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