1,720,967 research outputs found
Design, synthesis and investigation of the photosensitive properties of mesoporous titania powders and donor-acceptor chromophores
Full text linkThe experimental work performed during this thesis was devoted to the design, synthesis and characterisation of photosensitive materials.On one side, synthesis of mesoporous titania powders through EISA method was performed. The influence of synthetic conditions (precursors type and molar ratio, ligand addition, calcination rates and temperatures, water addition and surfactant type) on both structural (phase composition and crystallite size) and morphological (surface areas, pore distribution and size) parameters were evaluated by X-Ray Powder Diffraction, N2 Physisorption measurements and Transmission Electron Microscopy. The materials were also tested as photoanodes in the water splitting reaction and the results compared to Degussa P25 as standard.On the other hand, synthesis, electrochemical and optical characterization of novel D-π-A dyes were performed. All the compounds obtained in each synthetic step were characterised in the same way, thus allowing to study the influence of the introduction of donor or acceptor fragments on a bithiophene backbone. Almost all the synthesised compounds were electropolymerised. The corresponding conducting polymers, which can be regarded as polymer dyes, were characterised by cyclic voltammetry and UV-Vis spectrophotometr
Synthesis and characterization of nanostructured mesoporous titania samples and their application as photoanodes in photoelectrochemical cells (PECs) for water splitting
No full textElectrochemical synthesis and characterization of terpyridine-tethered polythiophene bearing ethynyl bridge
No full textPolimeri conduttori a base tiofenica: effetto delle modifiche strutturali sull’estensione della coniugazione
No full text
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
Design, synthesis and investigation of the photosensitive properties of mesoporous titania powders and donor-acceptor chromophores
No full textThe experimental work performed during this thesis was devoted to the design, synthesis and characterisation of photosensitive materials.
On one side, synthesis of mesoporous titania powders through EISA method was performed. The influence of synthetic conditions (precursors type and molar ratio, ligand addition, calcination rates and temperatures, water addition and surfactant type) on both structural (phase composition and crystallite size) and morphological (surface areas, pore distribution and size) parameters were evaluated by X-Ray Powder Diffraction, N2 Physisorption measurements and Transmission Electron Microscopy. The materials were also tested as photoanodes in the water splitting reaction and the results compared to Degussa P25 as standard.
On the other hand, synthesis, electrochemical and optical characterization of novel D-π-A dyes were performed. All the compounds obtained in each synthetic step were characterised in the same way, thus allowing to study the influence of the introduction of donor or acceptor fragments on a bithiophene backbone. Almost all the synthesised compounds were electropolymerised. The corresponding conducting polymers, which can be regarded as polymer dyes, were characterised by cyclic voltammetry and UV-Vis spectrophotometr
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
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