1,720,955 research outputs found
) pyrazolate metallacycles
Get PDFThe preparation of materials having optical properties is a fertile area of research because of their application in OLEDs, sensors, and semiconducting materials science field. Moreover, considering environmental concerns, there is an increasing need in the scientific community to enhance the preparative methods using eco-friendly approaches. In this work, the mechanochemical liquid assisted grinding (LAG) method is applied for the syntheses of hybrid organometallic/organic materials made of pi-acidic silver(i) or copper(i) metallacycles, with bridging ligands such as 3,5-bis(trifluoromethyl)pyrazolate or 3,5-dinitro-pyrazolate, and coronene, a highly symmetric polycyclic aromatic molecule (PAH). The LAG method was monitored by FT-IR spectroscopy and SEM; the former was applied to study the slight structural modification upon interactions, and the latter was used to depict the changes in the solid surface morphology upon CH2Cl2-assisted grinding. On the other hand, the dissolution of the materials reversibly yields the starting compounds. The stacked materials were characterized by elemental and TGA analyses, and photoluminescence (PL), and IR spectroscopies. The PL study highlights the room temperature quenching of the coronene emissions at 505 nm, indicating the occurrence of dispersive electrostatic interactions. Interestingly, the solid-state UV-Vis study allowed the calculations of direct (2.27 eV) and indirect (2.78 eV) band gaps for the D/A adduct {[3,5-(CF3)2pz]Ag}3@coronene, 1, with values featuring the materials in the semiconductor band gap range, useful for application in OFETs or OPVs
Halogen addition to NHC-gold(I) chloride complexes in the framework of the Inverted Ligand Field
No full textThe conversion of LAuX to LAuX3, where L is a neutral ligand such as a phosphane or a carbene and X = Cl, Br or I, can be performed by halogen addition reactions in mild conditions. The formation of complexes with mixed halides, such as LAuY2X, also evoking the possibility of geometrical isomerization, is less investigated. In this work the iodine and bromine addition reactions, under mild conditions, to a symmetrically disubstituted carbene 1,3-dimethyl-imidazolyl-2-yl-gold(I)chloride were considered. The molecular structures highlight the formation of the trans LAuI2Cl in the case of iodine addition and a mixture of the geometrical isomers for bromine. DFT analysis points out a stepwise addition of halogen atom to the linear gold(I) complex without a net change in metal electronic population, suggesting the occurrence of the Inverted Ligand Field
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
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
