1,721,072 research outputs found
Metalloporphyrins in the Biomimetic Oxidation of Lignin and Lignin Model Compounds: Development of Alternative Delignification Strategies
No full textChimica generale e inorganica
No full textQuesto libro di Chimica generale e inorganica è rivolto agli studenti delle materie scientifiche universitarie. Gli Autori sono tutti coinvolti, da molti anni e a vario titolo, sia nella ricerca di base sia in quella applicativa e hanno acquisito una notevole esperienza anche per quanto riguarda la didattica attraverso lo svolgimento di corsi di Chimica sia per Scienze matematiche e naturali sia per la facoltà di Ingegneria. Questo testo di Chimica vuole fornire, oltre alla base teorica della Chimica moderna, anche una visione più applicativa, proposta dagli approfondimenti inseriti in ogni capitolo, che amplia la conoscenza degli argomenti oggetto di studio e di interesse personale. Ai contenuti digitali possono accedere sia lo studente sia il docente. Per lo studente sono disponibili approfondimenti, laboratori didattici, video, percorsi guidati o specifiche serie di test di autovalutazione che vengono continuamente aggiornati. Il docente potrà avere accesso a tutte le immagini in formato elettronico per la preparazione delle proprie lezioni e disporre di un cospicuo numero di esercizi con cui allestire, in tempi estremamente brevi, elaborati scritti sempre diversi
New Insights into the Structure of Glycols and Derivatives: A Comparative X-Ray Diffraction, Raman and Molecular Dynamics Study of Ethane-1,2-Diol, 2-Methoxyethan-1-ol and 1,2-Dimethoxy Ethane
Full text linkIn this study, we report a detailed experimental and theoretical investigation of three glycol derivatives, namely ethane-1,2-diol, 2-methoxyethan-1-ol and 1,2-dimethoxy ethane. For the first time, the X-ray spectra of the latter two liquids was measured at room temperature, and they were compared with the newly measured spectrum of ethane-1,2-diol. The experimental diffraction patterns were interpreted very satisfactorily with molecular dynamics calculations, and suggest that in liquid ethane-1,2-diol most molecules are found in gauche conformation, with intramolecular hydrogen bonds between the two hydroxyl groups. Intramolecular H-bonds are established in the mono-alkylated diol, but the interaction is weaker. The EDXD study also evidences strong intermolecular hydrogen-bond interactions, with short O···O correlations in both systems, while longer methyl-methyl interactions are found in 1,2-dimethoxy ethane. X-ray studies are complemented by micro Raman investigations at room temperature and at 80 ◦C, that confirm the conformational analysis predicted by X-ray
experiments and simulations
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
Novel Synthesis of Zinc Oxide Nanoparticles from Type IV Deep Eutectic Solvents
Full text linkOne of the fields where DES show remarkable added-values is the synthesis of inorganic materials, in particular nanoparticles. In this field, the inherent and highly-tunable nano-homogeneities of DES structure give origin to a marked templating effect, a precious role that has led to the recent bloom of a vast number of studies exploiting these new synthesis media to prepare nanomaterials and composite structures of various kinds. In this contribution, three examples of synthesis of nanoparticles containing zinc, using metal type-IV Deep Eutectic Solvents, a pathway that has never been explored so far, is described. The prepared materials have layered shapes, and when zinc nitrate is used as DES component, pure layered ZnO is obtained, forming nanometric platelets that assemble to form flower-like aggregates. The prepared nanoparticles show intrinsic fluorescence, and are being further studied to set up sensors for the detection of various contaminants
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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