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101.
Francesca Zavarise Encarnació Companys Josep Galceran Giancarla Alberti Antonella Profumo 《Analytical and bioanalytical chemistry》2010,397(1):389-394
Absence of gradients and Nernstian equilibrium stripping (AGNES) is a recently developed electroanalytical technique specifically designed for the direct determination of free concentrations of metal ions. AGNES is applied here to the determination of free Zn concentration in a river water sample. The method has been validated with synthetic solutions of low ionic strengths containing Zn and 2,6-pyridinedicarboxylic acid and then applied to synthetic river waters and to a natural sample collected from Besòs River in Montcada i Reixac (Catalonia, North-Eastern Spain). In the river sample, an average free Zn concentration of 12.8(4) nM was obtained, while the total dissolved Zn concentration was 0.51(8)?μM. To control and maintain pH and pCO2 constant during AGNES measurements, a novel device for N2/CO2 mixed purging has been developed. 相似文献
102.
Plaia Antonella Sciandra Mariangela 《Advances in Data Analysis and Classification》2019,13(2):427-444
Advances in Data Analysis and Classification - Within the framework of preference rankings, the interest can lie in finding which predictors and which interactions are able to explain the observed... 相似文献
103.
H. Z. Munthe-Kaas G. R. W. Quispel A. Zanna 《Foundations of Computational Mathematics》2001,1(3):297-324
The polar decomposition, a well-known algorithm for decomposing real matrices as the product of a positive semidefinite matrix and an orthogonal matrix, is intimately related to involutive automorphisms of Lie groups and the subspace decomposition they induce. Such generalized polar decompositions, depending on the choice of the involutive automorphism σ , always exist near the identity although frequently they can be extended to larger portions of the underlying group. In this paper, first of all we provide an alternative proof to the local existence and uniqueness result of the generalized polar decomposition. What is new in our approach is that we derive differential equations obeyed by the two factors and solve them analytically, thereby providing explicit Lie-algebra recurrence relations for the coefficients of the series expansion. Second, we discuss additional properties of the two factors. In particular, when σ is a Cartan involution, we prove that the subgroup factor obeys similar optimality properties to the orthogonal polar factor in the classical matrix setting both locally and globally, under suitable assumptions on the Lie group G . September 12, 2000. Final version received: April 16, 2001. 相似文献
104.
Antonella Marini Thomas H. Otway 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2014
Duality methods are used to generate explicit solutions to nonlinear Hodge systems, demonstrate the well-posedness of boundary value problems, and reveal, via the Hodge–Bäcklund transformation, underlying symmetries among superficially different forms of the equations. 相似文献
105.
Summary An analytical procedure is described for the analysis of archaeological glass by inductively coupled plasma optical emission spectroscopy (ICP-OES). Glass samples were analysed in solution after fusion with lithium metaborate at 1100°C. The analyses were performed in the sequential multielemental mode of operation, with the determination of 15 elements in four analytical runs; only elements with not too large concentration difference were analysed in a single run. The following elements were accounted for: Si, Na, Ca, Al, Fe, Mg, Mn, Ti, Sr, Ba, Cr, Ni, Cu, Co, Pb. 相似文献
106.
107.
Antonella Grassi 《Mathematische Annalen》1991,290(1):287-301
108.
Giovanni Ricci Aldo Boglia Tiziano Motta Fabio Bertini Antonella Caterina Boccia Lucia Zetta Enrica Alberti Antonino Famulari Paolo Arosio Stefano Valdo Meille 《Journal of polymer science. Part A, Polymer chemistry》2007,45(22):5339-5353
The (E) isomer in mixtures of (E) and (Z) 1,3‐hexadiene was polymerized with the system CoCl2(PiPrPh2)2‐MAO, a highly active and stereospecific catalyst for the preparation of 1,2 syndiotactic polybutadiene. A new crystalline polymer with a melting point of 109 °C was obtained. The polymer was characterized by IR, NMR (13C, 1H in solution and 13C in the solid‐state), X‐ray diffraction, DSC, GPC and it was found to have a trans‐1,2 syndiotactic structure with a 5.18 ± 0.04 Å fiber periodicity. Since only the (E) isomer was polymerized, at the end of the reaction we were able to separate the (Z) isomer, which was ultimately polymerized with CpTiCl3‐MAO at low temperature, obtaining a low molecular weight, stereoregular polymer that, characterized by IR and NMR methods, was found to exhibit a cis‐1,2 syndiotactic structure, never reported before. Molecular mechanics calculations were carried out on the trans‐1,2 syndiotactic polymer and structural models consistent with the X‐ray diffraction data are proposed. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5339–5353, 2007 相似文献
109.
Boga C Forlani L Calienni R Hindley T Hochkoeppler A Tozzi S Zanna N 《Natural product research》2011,25(4):417-421
A decoction of Capparis spinosa L. roots, widely used in the traditional folk medicine of southern Italy, was prepared and submitted to antibacterial activity tests, which showed an interesting bacteriostatic activity on the growth of Deinococcus radiophilus. Heterocyclic compounds were also recovered from the chloroformic extract of the roots. 相似文献
110.
Elisa Barzagli Francesco Grazzi Francesco Civita Antonella Scherillo Antonino Pietropaolo Giulia Festa Marco Zoppi 《Applied Physics A: Materials Science & Processing》2013,113(4):1143-1150
In this work we present a systematic study of Japanese sword hand-guards (tsuba) carried out by means of non-invasive techniques using neutrons. Several tsuba from different periods, belonging to the Japanese Section of the Stibbert Museum, were analysed using an innovative approach to characterise the bulk of the samples, coupling two neutron techniques, namely Time of Flight Neutron Diffraction (ToF-ND) and Nuclear Resonance Capture Analysis (NRCA). The measurements were carried out on the same instrument: the INES beam-line at the ISIS spallation pulsed neutron source (UK). NRCA analysis allows identifying the elements present in the sample gauge volume, while neutron diffraction is exploited to quantify the phase distribution and other micro-structural parameters of the metal specimen. The results show that all samples are made of high-quality metal, either steel or copper alloy, with noticeable changes in composition and working techniques, depending on the place and time of manufacturing. 相似文献