1,721,064 research outputs found
The Covalent Functionalization of Graphene on Substrates
Get PDFThe utilization of grown or deposited graphene on solid substrates offers key benefits for functionalization processes, but especially to attain structures with a high level of control for electronics and “smart” materials. In this review, we will initially focus on the nature and properties of graphene on substrates, based on the method of preparation. We will then analyze the most relevant literature on the functionalization of graphene on substrates. In particular, we will comparatively discuss radical reactions, cycloadditions, halogenations, hydrogenations, and oxidations. We will especially address the question of how the reactivity of graphene is affected by its morphology (i.e., number of layers, defects, substrate, curvature, etc.)
Recent advances of graphene-based hybrids with magnetic nanoparticles for biomedical applications
No full textThe utilization of graphene-based nanomaterials combined with magnetic nanoparticles offers key benefits in the modern biomedicine. In this minireview, we focus on the most recent advances in hybrids of magnetic graphene derivatives for biomedical applications. We initially analyze the several methodologies employed for the preparation of graphene-based composites with magnetic nanoparticles, more specifically the kind of linkage between the two components. In the last section, we focus on the biomedical applications where these magnetic-graphene hybrids are essential and pay special attention on how the addition of graphene improves the resulting devices in magnetic resonance imaging, controlled drug delivery, magnetic photothermal therapy and cellular separation and isolation. Finally, we highlight the use of these magnetic hybrids as multifunctional material that will lead to a next generation of theranostics
Concluding remarks: Chemistry of 2-dimensional materials: beyond graphene
No full textSince graphene was exfoliated in 2004, two-dimensional (2D) materials have received great attention due to their physical and chemical properties associated with their nanosized thickness and the correlated quantum size effect. 2D planes allow the confinement of charge carriers, heat, and photons, leading to the remarkable electronic and optical properties of these materials. The Faraday Discussion "Chemistry of 2-dimensional materials: beyond graphene" has been an incredible showcase for a variety of highly interesting contributions in the field. This conference comprised a large number of aspects of the topic: from their synthesis and the study of their optical and physical properties to their numerous applications. These concluding remarks aim to capture the recent developments in 2D materials chemistry and physics that were presented and debated during this Faraday Discussion, and more generally in the research field in recent years. Particular attention will be paid to aspects like the synthesis of the materials, their toxicity and biodegradation, and some of their major applications in catalysis, as well as Li-ion batteries, water filtration and sensing. In addition we aim to highlight future challenges that still need to be addressed
Kovalente Funktionalisierung von Graphen auf Substraten
No full textDie Nutzung von auf festen Substraten gezogenem oder abgeschiedenem Graphen bietet wesentliche Vorteile, wenn man mithilfe von Funktionalisierungsprozessen fein abgestimmte Strukturen für die Elektronik und “intelligente” Materialien erzielen möchte. In diesem Aufsatz konzentrieren wir uns zunächst auf die Natur und die Eigenschaften von Graphen auf Substraten in Abhängigkeit von den jeweiligen Herstellungsverfahren. Anschließend analysieren wir die maßgebliche Literatur zur Funktionalisierung von Graphen auf einem Substrat. Insbesondere werden wir radikalische Reaktionen, Cycloadditionen, Halogenierungen, Hydrierungen und Oxidationen vergleichend diskutieren. Dabei werden wir besonders auf die Frage eingehen, wie die Reaktivität von Graphen durch seine Morphologie beeinflusst wird (d. h. Anzahl von Lagen, Defekte, Substrat, Krümmung usw.)
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
Electrochemiluminescent immunoassay enhancement driven by carbon nanotubes
Get PDFElectrochemiluminescence (ECL) is a leading analytical technique for clinical monitoring and early disease diagnosis. Carbon nanotubes are used as efficient nanomaterials for ECL signal enhancement providing new insights into the mechanism for the ECL generation but also affording application in bead-based immunoassay and ECL microscopy-based bioimaging
New insights into the exploitation of oxidized carbon nitrides as heterogeneous base catalysts
Get PDFIn this work, the development of a novel efficient heterogeneous catalytic system capable of driving Knoevenagel
condensation reactions between benzaldehydes and malononitrile was reported. Specifically, we explored a postsynthetic
modification of graphitic carbon nitride (g-CN) through a strong oxidation treatment by acid mixture
(HNO3/H2SO4). The as-prepared oxidized CN material (CNO) shows a large number of surface acidic moieties,
that can be easily deprotonated through an aqueous alkaline wash with different bases (NaOH, K2CO3, t-BuOK),
to introduce a high density of reactive basic sites. The best catalyst is obtained with NaOH as the base (CNONaOH),
and displays high reactivity and good tolerance towards functional group variations of the reagents, thus
emerging as a potential new recyclable carbon nitride-based structure for organic base catalysis
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
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