1,720,980 research outputs found
Synthesis and characterization of a cobalt(III) complex with 1-(D-3 Mercapto-2-methylpropionyl)-L-proline
No full textA Review on Energy Dispersive X-ray Diffraction technique applied to disordered systems
No full textA review. The recent growing interest in amorphous and liq. materials has triggered new studies aiming at the detn. of local structures. Due to the large varieties of the non-cryst. materials the motivations of such studies were of different types, but in all cases reliable and relatively fast detn. of the local structures were required. In this review we present the application of the Wide Angle X-ray Scattering (WAXS) by energy dispersive detection as a tool to investigate a large variety of amorphous and liq. materials. We present, among them, samples of biol. and pharmaceutical interest, different types of catalysts, mol. liqs., polymers with different industrial applications as well as metal-phtalocyanines and materials devoted to the org. synthesis such as the cetylalkylammonium tribromides
Palladium (II) and platinum (II) aqueous solutions. Evidence for the solvation of the [PdCl4](2-) and [PtCl4](2-) ions
No full textThe isomorphic substitution applied to solutions of NH4PtCl4 and NH4PdCl4 allows to show the existence of 2 bound water molecules at the apical sites of PtCl42- and PdCl42- ions. The Pt(Pd)-H2O distance results equal to 2.77 Angstrom. (C) 1998 Elsevier Science B.V
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
Study of cetyltrialkylammonium bromide and tribromide salts in the solid phase
No full textSome cetyltrialkylammonium tribromide salts have been studied in the solid phase using Raman spectroscopy and energy dispersive X-ray diffraction. The first technique detected the presence of asymmetric tribromides while the latter technique revealed the degree of asymmetry of the tribromide units (difference in the bond lengths between external and central Br atoms), by application of a subtraction method. In this method the spectra of the corresponding monobromide salts were recorded and differences between tribromide and monobromide curves isolated the tribromide contributions. The existence of asymmetrical and symmetrical tribromide ions has been established and the degree of asymmetry was then correlated to the steric hindrance and electronegativity of the ammonium substituents. The values of the Br-Br bond distances have been deduced; the most asymmetric tribromide has Br-Br distances at 2.38 and 2.66 Angstrom, while the symmetric tribromide has both Br-Br bond lengths equal to 2.52 Angstrom. A linear geometry is confirmed for the tribromide ions
Conductivity and structure of poly(ethylene glycol) complexes using energy dispersive X-ray diffraction
No full textTriflate salts of Mg(II), Zn(II), and Cu(II) in Liquid, low weight poly(ethylene glycol) dimethyl ether (PEGM-(400)) to determine their conductivity and to ascertain their possible use as electrolyte media, have been studied. Their liquid structures have been studied by energy-dispersive X-ray diffraction. By this technique, the cation geometrical coordination has been determined. Furthermore, the local structure of the bivalent cations has been singled out by application of the difference method to isomorphic solutions. We found that the investigated cations have an octahedral coordination, with the exception of Cu, which displays two apical bonds longer than the planar ones. We also found that the polymer chain is coordinated to the cations Mg and Zn through the oxygen atoms of the polymer units 1, 5, and 9
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
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