1,720,986 research outputs found
Functionalization Of Graphene And Reduced Graphene Oxide In Different Matrices
No full textGraphene (G) presents a huge variety of intriguing properties, as extraordinary electronic transport characteristics.
G, thanks to its low chemical reactivity, can also be used as an active support for catalytic nanoparticles. Some possible
graphene application could be: its employment in active material in electronic devices such as sensors [1], batteries [2],
supercapacitors, hydrogen storage systems or as fillers to produce multifunctional nanocomposite polymeric materials [3].
In more detail we would like to examine: different approach of reduction and functionalization of in situ reduced graphene
oxide obtaining an enhancement of thermal conductivity and an resistivity decrease [4]. Surface modification and
functionalization of rGO to improve its dispersion in organic solvent and also polymeric matrix [5]
Chemical Reactivity and Variation in Electronic Properties of Graphene on Ni(111) and Reduced Graphene Oxide
No full textIn this chapter I will describe the chemical reactivity and the electronical properties variation of graphene (G) supported on Ni(111) and of the reduced Graphene Oxide (rGO).
The reason behind this double choice is to give a complete overview of this innovative material from the fundamental point of view and more applicative studies.
These researchers were developed in the framework of University of Genoa, Polytechnic of Turin and Istituto Italiano di Tecnologia, Center for Space Human Robotic IIT@PoliTo (Italy).
1) In the first part of this chapter I will present the main results obtained on the reactivity, towards CO, of pristine graphene grown on Ni(111). Single layer graphene films are grown by ethene dehydrogenation on Nickel, under different experimental conditions, and the system is studied in-situ by X-ray Photoelectron and High Resolution Electron Energy Loss Spectroscopies, before and after CO exposure at 87 K and at room temperature.
The main results were:
- the best CO reactivity in the top-fcc configuration1,2 of graphene on Ni(111), at low temperature3.
- the higher reactivity occurs in the case of minimum percentage of contaminant or Ni2C still present during the grown process2.
The second step consists in modifying the pristine graphene, which is inert at room temperature, inducing punctual defects, by controlled sputtering. I obtained an unexpected reactivity toward CO also at room temperature, with possible applications e.g., gas sensing4,5
2) In the second part of the chapter I will be describe more applicative aspect of GO and rGO systems developed previously at Polytechnic of Turin and IIT@PoliTo.
Modifying this material, during the reduction, I studied the possibility to improve his electrical properties opening possible application in the ink-jet printing mechanism as conductive printing system6, or in the functionalization of graphene7.
In particular the surface modification of GO, by two steps Ultraviolet (UV) based process, allowed to improve the dispersion of GO in organic solvent and polymeric matrix. This process results particular appealing for instance in the fabrication of printable inks and coatings.
Finally, I will explain the use of rGO membranes for one daily application regarding the desalinization process of water
Flash nanoprecipation as a simple route to produce smart polymeric drug delivery devices
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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
Morphology of monolayer MgO films on Ag(100): Switching from corrugated islands to extended flat terraces
No full textVariations 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
A powerful tool for graphene functionalization: Benzophenone mediated UV-grafting
No full textThe surface modification of graphene is of fundamental importance when working on the fabrication of high performing polymeric nanocomposite exploiting the exciting properties of this carbon-based material. Using low cost graphene oxide as starting material, trading on its richness of-OH groups and its ability to be reduced under UV light, a facile two-step UV-based process for the reduction to graphene and the simultaneous covalent grafting of initiating moieties at its surface is here proposed. This procedure enables the subsequent photo-grafting of a great variety of monomers for graphene surface functionalization.
Chemical, structural and electrical analysis of the functionalized graphene sheets demonstrated the reduction of the starting oxide and the grafting of the initiator and of the acrylic monomers used in this study. This procedure opens the route for a low cost production of grafted graphene that can be easily dispersed in organic matrices, in order to produce highly performing functional materials
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
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