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131.
Giuseppe Giovannelli Lucia D’Urzo Giovanna Maggiulli Stefano Natali Cosimo Pagliara Ivonne Sgura Benedetto Bozzini 《Journal of Solid State Electrochemistry》2010,14(3):479-494
This paper concentrates on a novel approach to the electrochemical treatment of bronze disease, based on the use of room-temperature
ionic liquids (RTIL). In particular, we employed 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide as the electrolyte
for the galvanostatic cathodic treatment of a late bronze-age artifact that had been exposed to marine environment during
its history, dating back to ca. 1100 B.C. After an accurate metallographic and structural analysis of the as-found object—proving,
among other findings, that bronze disease is essentially related to the presence of nantokite locked inside subsurface pits
of typical equivalent diameter of several hundred micrometers, we subjected it to optimal electrochemical conditions, showing—on
the basis of X-ray diffraction—that nantokite could be effectively removed and Cu(I) reduced to metallic Cu. Numerical computations
in the full three-dimensional pit geometry, with realistic nonlinear electrochemical boundary conditions, provide the theoretical
framework for the choice of RTIL—as opposed to aqueous solutions—and for the quantitative evaluation of Cl− removal rates. 相似文献
132.
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135.
Claudio Mele Sandra Rondinini Lucia D’Urzo Vincenzo Romanello Elisabetta Tondo Alessandro Minguzzi Alberto Vertova Benedetto Bozzini 《Journal of Solid State Electrochemistry》2009,13(10):1577-1584
Nucleation and growth of silver, electrodeposited from water–acetonitrile (CH3CN from 0 to 100% by volume) mixed solvents on glassy carbon electrodes, was studied by means of double-sweep voltammetry,
current–time transients (CTT) and scanning electron microscopy (SEM). The effects of the addition of the specifically interacting
tetrabuthylammonium cation were also investigated. From voltammetries, the formal potential, the nucleation potential and
the cathodic current efficiency have been evaluated as a function of the mixed solvent composition. The key role on nucleation
kinetics of transferring Ag+ from the bulk phase to the CH3CN-enriched electrode/solution interphase has been highlighted. CTT transients were described by a model combining instantaneous
and progressive nucleation mechanisms. SEM images highlighted the effects of the presence of the organic solvent, which yields
to a more regular growth, and of the quaternary ammonium salt, which exhibits grain-refining properties. 相似文献
136.
The theme is to smooth characteristic functions of Parseval frame wavelet sets by convolution in order to obtain implementable, computationally viable, smooth wavelet frames. We introduce the following: a new method to improve frame bound estimation; a shrinking technique to construct frames; and a nascent theory concerning frame bound gaps. The phenomenon of a frame bound gap occurs when certain sequences of functions, converging in L 2 to a Parseval frame wavelet, generate systems with frame bounds that are uniformly bounded away from 1. We prove that smoothing a Parseval frame wavelet set wavelet on the frequency domain by convolution with elements of an approximate identity produces a frame bound gap. Furthermore, the frame bound gap for such frame wavelets in L 2(? d ) increases and converges as d increases. 相似文献
137.
Fulvia Felluga Giuliana Pitacco Ennio Zangrando Egon Rizzato Giovanni Petrillo 《Tetrahedron》2006,62(37):8787-8791
The reaction of the lithium enolate of 1-benzyl-5-oxo-3-pyrrolidinecarboxylic acid 3 with a series of β-aryl, β-nitroenamines unexpectedly afforded 6-aryl-2-benzyl-4-oxa-1-oxo-3a-methoxycarbonyl-2,5-diazaindenes 9a-d, whose structure was determined by analytical and NMR spectroscopical analysis. The structure of 9b was further confirmed by X-ray analysis. A reasonable mechanism for their formation is given. 相似文献
138.
Moggio L De Napoli L Di Blasio B Di Fabio G D'Onofrio J Montesarchio D Messere A 《Organic letters》2006,8(10):2015-2018
[structure: see text] A new and versatile on-line automated solid-phase approach to obtain cyclic PNA (I and III) and cyclic PNA-DNA chimeras (II) in highly pure form has been developed. Starting from a Tentagel matrix functionalized with a 3-chloro-4-hydroxyphenylacetic linker, the synthesis of representative, new cyclic molecules by standard peptide and phosphoramidite-based chemistry has been achieved. 相似文献
139.
The fact that every combinator has a fixed point is at the heart of the -calculus as a model of computation. We consider several aspects of such phenomenon; our specific, perhaps eccentric, point of view focuses on problems and results that we consider worthy of further investigations. We first consider the relation with self application, in comparison with the opposite view, which stresses the role of coding, unifying the first and the second fixed point theorems. Then, we consider the relation with the diagonal argument, a relation which is at the origin of the fixed point theorem itself. We also review the Recursion Theorem, which is considered a recursion theoretic version of the fixed point theorem. We end considering systems of equations which are related to fixed points. 相似文献
140.
Let H = ?d 2/dx 2 + V be a Schrödinger operator on the real line, where \({V=c\chi_{[a,b]}}\) , c > 0. We define the Besov spaces for H by developing the associated Littlewood–Paley theory. This theory depends on the decay estimates of the spectral operator \({{\varphi}_j(H)}\) for the high and low energies. We also prove a Mihlin multiplier theorem on these spaces, including the L p boundedness result. Our approach has potential applications to other Schrödinger operators with short-range potentials. 相似文献