1,720,983 research outputs found
Synthesis of new red photoluminescent Zn(II)-Salicylaldiminato complex
No full textWe report the preparation and photophysical properties of a new zinc (II) complex of the donor-acceptor-donor (D-A-D) type ligand N,N'-bis(2-hydroxy-1-naphthylidene)-diaminomaleonitrile (H2L). The molecular structure of the (ZnL)center dot DMFI center dot DMF complex was determined by single crystal X-ray crystallography. The complex exhibits remarkable optical features attributed to the intramolecular charge transfer (ICT) with a striking red emission. Fluorescence studies of H2L and ZnL reveal that the quantum yield strongly increases upon coordinatio
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
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
Deep control of linear oligomerization of glycerol using lanthanum catalyst on mesoporous silica gel
Full text linkThe valorization of glycerol (1), a waste of biodiesel production of Fatty Acid Methyl Esters (FAMEs), adopting a “green” approach, represents an important goal of sustainable chemistry. While the polymerization of 1 to hyperbranched oligomers is a well-established process, the linear analogues are difficult to obtain. In this context, we explore the reaction without the solvent of heterogeneous hybrid La(III)O-KIT-6 catalyst (2), which is based on lanthanum oxide on mesoporous silica gel, showing a superior linear selectivity compared to most of the analogous catalysts recently reported
Copolimerizzazione catalitica in-situ di monossido di carbonio e olefine in presenza di silicati a strati e particelle ibride organico/inorganico
No full textA Sustainable Multistage Process for Immobilizing Bioactive Compounds on Layered Double Hydroxides
Full text linkHybrid systems with antioxidant properties have been developed by integrating bioactive compounds derived from plant resources with layered double hydroxides (LDHs). Anion exchange has been used to substitute intercalated nitrate anions in Mg-Al LDH with carboxylate anions derived from trans-ferulic acid, rosmarinic acid, and 18β-glycyrrhetinic acid. These organic compounds are known for their powerful antioxidant, anti-inflammatory and antimicrobial properties and are highly suitable for cosmetics, biomedicine, and food packaging. To enhance sustainability, a multistage procedure has been developed with the aim of recovering unexchanged carboxylate anions from residual reaction water, ensuring an environmentally friendly and easily scalable preparation process. The process, adapted for each of the three molecules, allows the production of a consistently high-quality hybrid product containing an organic fraction ranging from 10 to 48% by weight, depending on the specific molecule used. The immobilization of organic compounds has occurred either within the layers of LDH through intercalation or on the external surface through adsorption. Good antioxidant capacity has been exhibited by these powdered hybrid systems, as assessed through both the DPPH and linoleic acid/β-carotene tests. Sustainable production practices are enabled by this innovative approach, which also opens avenues for the development of advanced materials for diverse applications across various industries
Platinum nanoparticles onto pegylated poly(lactic acid) stereocomplex for highly selective hydrogenation of aromatic nitrocompounds to anilines
No full textCarbon monoxide-olefins co-(ter-)polymerization in the presence of GTR (Ground Tyre Rubber) microparticles
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