1,720,969 research outputs found
Porous Ternary High Performance Supercapacitor Electrode Based on Reduced Graphene Oxide, NiMn2O4, and Polyaniline
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This paper reports a novel porous ternary nanohybrid based on NiMn2O4, reduced graphene oxide, and polyaniline (GNMOP) as a superior supercapacitor electrode material. GNMOP was fabricated using a hydrothermal-assisted thermal annealing method, followed by the conductive wrapping of polyaniline through in-situ polymerization. The structure and morphology of the ternary nanohybrid were characterized by field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR). FTIR, XRD, and XPS confirmed the formation of ternary nanohybrid. SEM and Brunauer-Emmett-Teller (BET) measurement revealed the porous nature of GNMOP, whereas HRTEM analysis demonstrated the wrapping of conducting polyaniline (PANI) on binary composite. Such PANI wrapping enhanced the electrochemical performance of the binary nanocomposite. A specific capacitance of 757 Fg (1) was achieved for GNMOP at a current density of 1 Ag (1), which is much higher than that of the binary nanocomposite and mixed transition metal oxide. In addition, GNMOP exhibited a maximum energy density of 70 Whkg (1) and high capacitance retention of similar to 93% after 2000 cycles. These outstanding electrochemical performances of GNMOP can be attributed to the proper wrapping of conducting polymer and the synergistic impact of distinct components. (C) 2016 Elsevier Ltd. All rights reserved.</p
Microwave bottom-up route for size-tunable and switchable photoluminescent graphene quantum dots using acetylacetone: New platform for enzyme-free detection of hydrogen peroxide
No full textWe report a microwave sequential bottom-up route to produce green and blue luminescent graphene quantum dots (g-GQDs and b-GQDs) with size-tunable and switchable functionalities by tailoring the diameter size and functional groups via microwave carbonization and aromatization processes from acetylacetone as a starting organic solvent. The b-GQDs as the final product show only one emission peak at 433 nm and pH-independent blue luminescence, because two-step microwave irradiation could reduce the size and the oxygen-functional groups of the g-GQDs as an intermediate product. Also, the b-GQDs provide an exemplar enzyme-free platform for hydrogen peroxide detection through the electrochemical sensing due to much higher electron density and electron donating properties. In contrast, the g-GQDs show two different switchable photoluminescent emissions at similar to 460 nm (P1) and similar to 500 nm (P2): the P1 emission with sky-blue fluorescence originates from randomly conjugated oxygen-functional groups on the basal plane and/or edge of the g-GQDs and the P2 emission with green fluorescence results from quasi-molecular fluorophores formed by the electronic coupling of carboxylic acid groups.
Facile synthesis of Fe3O4 nanorod decorated reduced graphene oxide (RGO) for supercapacitor application
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The development of electrode materials capable of delivering high electrochemical performance is a major challenge. Herein, we demonstrate a facile approach for the synthesis of rod-shaped Fe3O4 nanostructures anchored on the reduced graphene oxide (RGO) surface and its application as an active electrode material for supercapacitors. The RGO-Fe3O4 nanocomposite was prepared by the spontaneous deposition of the rod-like FeOOH nanostructure onto the self-reduced GO surface followed by a thermal annealing process. The physical characterizations demonstrate the decoration of the rod-like Fe3O4 nanostructure over the RGO surface. Morphology analysis demonstrates that Fe3O4 nanorods with an average size of 150 nm are distributed over the RGO surface. The surface area analysis demonstrates that the as-synthesized RGO-Fe3O4 nanorod nanocomposite has 186 m(2) g(-1) specific surface area, which is higher compared to the Fe3O4 nanorods. As an active electrode material, the RGO-Fe3O4 nanocomposite shows excellent electrochemical performance compared to Fe3O4 nanorods. On the RGO-Fe3O4 nanocomposite based electrode a specific capacity of 315 C g(-1) was observed at 5 A g(-1) current density. Additionally, the RGO-Fe3O4 nanocomposite based electrode displayed excellent cycling stability with 95% specific capacity retention after 2000 cycles. The electrochemical results demonstrates that the RGO-Fe3O4 nanocomposite could be a promising material for energy conversion and storage.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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