1,721,021 research outputs found

    Surface and electrocatalytic properties of well-defined and vicinal RuO2 single crystal faces

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    The kinetics of Cl-2 evolution from concentrated NaCl solutions on the (110) and (230) faces of RuO2 single crystals has been investigated by determining the Tafel slope, the stoichiometric number and the reaction orders with respect to Cl- and H+. The experimental parameters suggest that the mechanism is presumably similar to that put forward earlier by Krishtalik [51] for RuO2 layers, but a step common to oxygen evolution, like the case of polycrystalline samples, is present only with the (230) face. Reasons for this difference and for the apparent lower activity of the (110) face with respect to the (230) are discussed. A detailed analysis of the surface behavior of the two faces in Cl- free acid and alkaline solutions has also been carried out by cyclic voltammetry

    A New Molecular Structure Representation: Spectral Wheighted Molecular (SWM) Signals and "SWIM" Descriptors.

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    Proceedings in: “Molecular modelling and prediction of bioactivity” K.Gundertofte and F.S. Jorgensen Ed., Kluwer, (2000), 34

    Analytical characterisation of inorganic suspended matter in the Milan urban aerosol by micro FT-IR spectroscopy (part II)

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    Infrared spectra of an urban aerosol sample selected by an impactor have been analysed by using PCA and PLS multivariate analyses. The presence of carbonates, nitrates, sulphates silicates and ammonium salts have been observed. The experimental spectra have been simulated as linear combinations of reference spectra

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Classification of ancient Etruscan ceramics using statistical multivariate analysis of data

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    About one hundred Etruscan ceramic shards dating from the VIII to the IV century BC and coming from the archaeological excavation at Pian di Civita in Tarquinia (central Italy) have been analyzed by inductively coupled plasma optical emission spectrometry and flame atomic emission spectrometry in order to settle their provenance and to acquire knowledge about the ceramic production technology. The examined shards belong to the class of the depurata pottery, a fine ware produced in Tarquinia over a long period, and are representative of different sub-classes. The samples have been analyzed for fifteen elements (Ca, Al, Mg, Fe, Ti, Cr, Cu, Ni, Zn, Mn, Zr, Sr, Na, K and Rb). The data acquired have been treated by multivariate analysis techniques such as principal component analysis and Kohonen artificial neural networks. Most of the analyzed shards have been locally produced as belonging to a unique large group. A continuity in usage of both choice of materials and technology has been recognized
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