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1.
Summary A screening model (CISP) is presented for the calculation of maximum predicted concentrations from a single point source,
which is particularly useful in situations where on-site meteorological measurements are limited or unavailable. CISP utilizes
an analytical solution of the advection diffusion equation which is non-Gaussian in form. CISP performance in evaluating maximum
ground-level concentrations was compared with that of the Environmental Protection Agency (EPA) Regulatory PTPLU2 Gaussian
model. 相似文献
2.
Regioselectivity and stereoselectivity of nucleophilic addition to glycal and imino‐glycal vinyl epoxides and their carba analogs: a rationalization based on HSAB theory and MEP 下载免费PDF全文
3.
The addition reaction of monomeric lithium enolate (Z)-1, derived from propiophenone, to propene oxide 2, was examined to clarify the exact geometry of the transition state (TS) involved in this type of reaction. The eight possible TSs and the corresponding pathways, four leading to syn gamma-hydroxy ketone (gamma-HK) 3 and four leading to anti gamma-HK 4, were compared, using the B3LYP/6-31+G(d)//B3LYP/6-31+G(d) theory level in vacuo and in the presence of the reaction solvent (toluene/hexane). In every case, the favored pathway involves a TS where the enolate C=C and the epoxide C-C are in a gauche relationship and where the Li(+) is stabilized by some C-C and C-H sigma bonds of epoxide 2. 相似文献
4.
The first experimental evidence is reported of crystallization induced in an amorphous alloy by a high density of electronic excitation deposited along the path of swift heavy ions. The formation of nanocrystalline iron boride phases was observed in an amorphous Fe73.5Cu1Nb3Si13.5B9 alloy irradiated at low temperature with 5 GeV Pb ions up to fluences of 1 x 10(11) ions cm-2. No evidence for the formation of the Fe(Si) phase was found. This phenomenon was interpreted in terms of the relaxation of the high level of energy deposited in electronic excitations along the path of Pb ions in the target, which induces extensive stress and strain that could destabilize the amorphous structure. 相似文献
5.
R. Bongiovanni M. Sangermano A. Medici C. Tonelli G. Rizza 《Journal of Sol-Gel Science and Technology》2009,52(2):291-298
A dual-curing process is described for obtaining highly fluorinated acrylic networks containing nanosilica. The new materials
showed improved hardness, while maintaining the hydrophobicity of the fluorinated polymer. They were obtained by UV-curing
a suitable mixture of a perfluoropolyetherurethanediacrylate and alkoxysilanes, followed by a thermal treatment during which
the sol–gel process took place. The obtained crosslinked networks had a complex morphology: nanometric silica particles were
formed, as observed by TEM, and embedded in a biphasic crosslinked matrix made of perfluoropolyether domains and of copolymeric
crosslinked domains containing the polyurethane acrylic units and siloxane chains formed by the alkoxides condensation. 相似文献
6.
Ridgway MC Giulian R Sprouster DJ Kluth P Araujo LL Llewellyn DJ Byrne AP Kremer F Fichtner PF Rizza G Amekura H Toulemonde M 《Physical review letters》2011,106(9):095505
Swift heavy-ion irradiation of elemental metal nanoparticles (NPs) embedded in amorphous SiO(2) induces a spherical to rodlike shape transformation with the direction of NP elongation aligned to that of the incident ion. Large, once-spherical NPs become progressively more rodlike while small NPs below a critical diameter do not elongate but dissolve in the matrix. We examine this shape transformation for ten metals under a common irradiation condition to achieve mechanistic insight into the transformation process. Subtle differences are apparent including the saturation of the elongated NP width at a minimum sustainable, metal-specific value. Elongated NPs of lesser width are unstable and subject to vaporization. Furthermore, we demonstrate the elongation process is governed by the formation of a molten ion-track in amorphous SiO(2) such that upon saturation the elongated NP width never exceeds the molten ion-track diameter. 相似文献
7.
G. B. Rizza 《Annali di Matematica Pura ed Applicata》1959,47(1):81-90
Sunto La conoscenza delle curvature (ordinaria e mista) delle faccette caratteristiche di una varietà k?hleriana consente la determinazione
della curvatura di tntte le faccette delle varietà. 相似文献
8.
Alessandro Ciattoni Carlo Rizza Andrea Marini Andrea Di Falco Daniele Faccio Michael Scalora 《Laser \u0026amp; Photonics Reviews》2016,10(3):517-525
In recent years, unconventional metamaterial properties have triggered a revolution of electromagnetic research which has unveiled novel scenarios of wave‐matter interaction. A very small dielectric permittivity is a leading example of such unusual features, since it produces an exotic static‐like regime where the electromagnetic field is spatially slowly‐varying over a physically large region. The so‐called epsilon‐near‐zero metamaterials thus offer an ideal platform where to manipulate the inner details of the “stretched” field. Here we theoretically prove that a standard nonlinearity is able to operate such a manipulation to the point that even a thin slab produces a dramatic nonlinear pulse transformation, if the dielectric permittivity is very small within the field bandwidth. The predicted non‐resonant releasing of full nonlinear coupling produced by the epsilon‐near‐zero condition does not resort to any field enhancement mechanism and opens novel routes to exploiting matter nonlinearity for steering the radiation by means of ultra‐compact structures.
9.
Alessandro Ciattoni Rino Marinelli Carlo Rizza Elia Palange 《Applied physics. B, Lasers and optics》2013,110(1):23-26
We consider a mixture of metal-coated quantum dots dispersed in a polymer matrix and, using a modified version of the standard Maxwell-Garnett mixing rule, we prove that the mixture parameters (particles radius, quantum dots gain, etc.) can be chosen so that the effective medium permittivity has an absolute value very close to zero in the near-infrared, i.e. $|{\rm Re}(\epsilon)| \ll 1$ and $|{\rm Im}(\epsilon)| \ll 1$ at the same near-infrared wavelength. Resorting to full-wave simulations, we investigate the accuracy of the effective medium predictions and we relate their discrepancy with rigorous numerical results to the fact that $|\epsilon| \ll 1$ is a critical requirement. We show that a simple method for reducing this discrepancy, and hence for achieving a prescribed and very small value of $|\epsilon|, $ consists in a subsequent fine-tuning of the nanoparticles volume filling fraction. 相似文献
10.
G. B. Rizza 《Annali di Matematica Pura ed Applicata》1972,92(1):37-63
Sunto Su di una varietà quasi hermitiana V, la considerazione di alcune medie di curvature semplici e miste, relative a convenienti
sistemi di 2-spazi associati ad un 2-spazio α, dà informazioni sulla curvatura semplice Kα, sulla media
e sulla curvatura mista
(
=Jα). Due delle medie accennate riescono nulle; le altre danno luogo a relazioni di dipendenza lineare. Considerate per la
varietà V ipotesi di isotropia in media e di J-isotropia si ottengono teoremi del tipo di Schur. Altri risultati si stabiliscono
nel caso k?hleriano.
Entrata in Redazione il 25 novembre 1971.
Lavoro eseguito con contributo del C.N.R. nell'ambito del Gruppo Nazionale Strutture Algebriche, Geometriche e loro Applicazioni. I primi risultati sono stati annunciati in una riunione di Gruppo a Bologna (dicembre 1970) e in una conferenza tenuta all'Ist. Mat. Univ. Perugia (aprile 1971). 相似文献
Summary Let V be an almost Hermite space, α a tangent 2-dimensional space of V; five systems of tangent 2-spaces of V are considered, suitably related to α. The sectional curvature Kα, the mean value , and the bisectional curvature are expressed in terms of mean values of sectional and bisectional curvatures, evalued over the above mentioned systems. Two of the mean values vanish; linear relationships hold among the other ones. Schur-like theorems are proven under the assumption that V be isotropic in mean or J-isotropic. Further results are obtained for the case that V be a K?hler space.
Entrata in Redazione il 25 novembre 1971.
Lavoro eseguito con contributo del C.N.R. nell'ambito del Gruppo Nazionale Strutture Algebriche, Geometriche e loro Applicazioni. I primi risultati sono stati annunciati in una riunione di Gruppo a Bologna (dicembre 1970) e in una conferenza tenuta all'Ist. Mat. Univ. Perugia (aprile 1971). 相似文献