1,720,973 research outputs found
Removal of heavy metals from aqueous solutions by sorption on hydroxyapatite.
No full textHydroxypatite, heavy metals, EXAF
Application of a TES micro-calorimeter as high-energy resolution detector for hard X-rays at a synchrotron beam line
No full textCOLOURING AND OPACIFYING AGENT IN POLICROME ETRUSCAN GLASS: ARCHAEOMETRIC DATA FROM SYNCHROTRON μ XRF, μ XAS AND μ XRD
No full textEvolution of the local environment around Er upon thermal annealing in Er and O co-implanted Si
No full textPolycrome Etruscan glass: first archaeometric data from synchrotron μXRF, μXANES and XRPD,
No full text
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
Site of transition metal ions in ion-exchanged metal-doped glasses
No full textMetal-for-alkali ion-exchange is largely used to dope surface layer of glass with metal ions so inducing a modification of the optical properties of the doped layer, useful to fabricate low-loss optical waveguides. X-ray absorption spectroscopy is a particularly important technique used to investigate the site of the metal ions introduced into the matrix, in specific cases also singling out the dopant oxidation state. Two case studies are reported in this paper, namely Cu-for-Na and Ag-for-Na ion-exchange layers of silicate glasses. The experimental results show that the site of the dopant ion is different from the one that replaced alkali ion: while in the first case the Cu site (i.e. the first oxygen shell around the metal species) is a linear combination of the sites of the crystalline oxides (CuO or Cu2O), with linear combination coefficients that depend on the average oxidation state, in the case of Ag, the Ag-O distance is much longer than in the Ag2O. Moreover, it comes to depend critically on the dopant concentration and on the subsequent heating treatments, indicating a higher stability of the Ag sites that exhibit a shorter Ag-O distance
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