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排序方式: 共有270条查询结果,搜索用时 156 毫秒
41.
Mattia Perrone 《Journal of Functional Analysis》2009,256(11):3471-3489
We study Haagerup inequality for radial functions on uniform lattices in semisimple Lie groups, with respect to Riemannian metrics and, in some case, to word metrics. In particular we extend the Swiatkowski-Valette results to any lattice acting properly and essentially transitively on classical buildings. 相似文献
42.
The implementation of circuits with complex dynamics is a very challenging problem. In this paper we present a new chaotic circuit based on the dynamical equations introduced in IEEE Trans. Circuits Syst., I: Fundam. Theory Appl. 51, 2476-2490 (2004). This circuit has been realized by using programmable analog devices, and, in particular, field programmable analog arrays have been used to implement a two-dimensional 3x3 grid scroll chaotic attractor. The implementation of complex dynamics with low cost circuits is very appealing; moreover, the implementation of the chaotic attractor discussed in this paper is not present in the literature. The experimental results including the synchronization between two chaotic circuits show complete agreement with the simulation results reported in IEEE Trans. Circuits Syst., I: Fundam. Theory Appl. 51, 2476-2490 (2004). 相似文献
43.
Mattia Spano Alessandro Maccelli Giacomo Di Matteo Cinzia Ingallina Mariangela Biava Maria Elisa Crestoni Jean-Xavier Bardaud Anna Maria Giusti Alessia Mariano Anna Scotto DAbusco Anatoly P. Sobolev Alba Lasalvia Simonetta Fornarini Luisa Mannina 《Molecules (Basel, Switzerland)》2021,26(17)
The metabolite profile of fresh Goji berries from two cultivars, namely Big Lifeberry (BL) and Sweet Lifeberry (SL), grown in the Lazio region (Central Italy) and harvested at two different periods, August and October, corresponding at the beginning and the end of the maturation, was characterized by means of nuclear magnetic resonance (NMR) and electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR MS) methodologies. Several classes of compounds such as sugars, amino acids, organic acids, fatty acids, polyphenols, and terpenes were identified and quantified in hydroalcoholic and organic Bligh-Dyer extracts. Sweet Lifeberry extracts were characterized by a higher content of sucrose with respect to the Big Lifeberry ones and high levels of amino acids (glycine, betaine, proline) were observed in SL berries harvested in October. Spectrophotometric analysis of chlorophylls and total carotenoids was also carried out, showing a decrease of carotenoids during the time. These results can be useful not only to valorize local products but also to suggest the best harvesting period to obtain a product with a chemical composition suitable for specific industrial use. Finally, preliminary studies regarding both the chemical characterization of Goji leaves generally considered a waste product, and the biological activity of Big Lifeberry berries extracts was also investigated. Goji leaves showed a chemical profile rich in healthy compounds (polyphenols, flavonoids, etc.) confirming their promising use in the supplements/nutraceutical/cosmetic field. MG63 cells treated with Big Lifeberry berries extracts showed a decrease of iNOS, COX-2, IL-6, and IL-8 expression indicating their significant biological activity. 相似文献
44.
Infrared spectra of deuterated monofluoroacetylene, DCCF, have been recorded in the region between 320 and 850 cm?1 at an effective resolution ranging from 0.0024 to 0.0031 cm?1. In total, 6650 rotation vibration transitions were assigned to 37 bands involving the bending states with v4 + v5 and |l4+l5|, respectively, up to 3, allowing the characterisation of the ground state and of 18 vibrationally excited states. The vν5 bending fundamental has been studied for the first time. In addition, the difference band v3 ← v4 has been detected and analysed. All the assigned transitions have been fitted simultaneously by adopting a model Hamiltonian that takes into account the vibration and rotation l?type resonances. Rotational transitions in the ground and in bending excited states reported in the literature have been included in the global analysis. The set of 57 derived spectroscopic parameters reproduces 6130 infrared and 90 microwave and millimetre?wave transitions satisfactorily with root mean square values of 5.3 × 10?4 cm?1 and 77 kHz, respectively. 相似文献
45.
Sara Mattia 《Computational Optimization and Applications》2012,51(2):809-834
We address the problem of designing a multi-layer network with survivability requirements. We are given a two-layer network:
the lower layer represents the potential physical connections that can be activated, the upper layer is made of logical connections
that can be set up using physical links. We are given origin-destination demands (commodities) to be routed at the upper layer.
We are also given a set of failure scenarios and, for every scenario, an associated subset of commodities. The goal is to
install minimum cost integer capacities on the links of both layers in order to ensure that the commodities can be routed
simultaneously on the network. In addition, in every failure scenario the routing of the associated commodities must be guaranteed.
We consider two variants of the problem and develop a branch-and-cut scheme based on the capacity formulation. Computational
results on instances derived from the SNDLib for single node failure scenarios are discussed. 相似文献
46.
47.
Mattia Silvi Carlo Cassani Antonio Moran Paolo Melchiorre 《Helvetica chimica acta》2012,95(10):1985-2006
The direct and enantioselective γ‐alkylation of α‐substituted α,β‐unsaturated aldehydes proceeding under dienamine catalysis is described. We have found that the Seebach modification of the diphenyl‐prolinol silyl ether catalyst in combination with saccharin as an acidic additive promotes an SN1 alkylation pathway, while ensuring complete γ‐site selectivity and a high stereocontrol. Theoretical and spectroscopic investigations have provided insights into the conformational behavior of the covalent dienamine intermediate derived from the condensation of 2‐methylpent‐2‐enal and the chiral amine. Implications for the mechanism of stereoinduction are discussed. 相似文献
48.
While the stability of liquid films on substrates is a classical topic of colloidal science, the availability of nanostructured materials, such as nanotubes, nanofibres and nanochannels, has raised the question of how the stability of liquid films and their wetting behaviour is affected by nanoscale confinement. This paper will present the conditions for the stability of liquid films on and inside cylindrical solid substrates with nanometre scale characteristic dimensions. It is shown that the stability is determined by an effective disjoining/conjoining pressure isotherm which differs from the corresponding disjoining/conjoining pressure isotherm of flat liquid films on flat solid substrates. From the former, the equilibrium contact angles of drops on an outer or inner surface of a cylindrical capillary have been calculated as a function of surface curvature, showing that the expressions for equilibrium contact angles vary for different geometries, in view of the difference in thickness of the film of uniform thickness with which the bulk liquid (drops or menisci) is at equilibrium. These calculations have been extended to the case of glass nanocapillaries and carbon nanotubes, finding good agreement with experimental results in the literature. 相似文献
49.
Anatoly P. Sobolev Cinzia Ingallina Mattia Spano Giacomo Di Matteo Luisa Mannina 《Molecules (Basel, Switzerland)》2022,27(22)
In this review, the three different NMR-based approaches usually used to study foodstuffs are described, reporting specific examples. The first approach starts with the food of interest that can be investigated using different complementary NMR methodologies to obtain a comprehensive picture of food composition and structure; another approach starts with the specific problem related to a given food (frauds, safety, traceability, geographical and botanical origin, farming methods, food processing, maturation and ageing, etc.) that can be addressed by choosing the most suitable NMR methodology; finally, it is possible to start from a single NMR methodology, developing a broad range of applications to tackle common food-related challenges and different aspects related to foods. 相似文献
50.
Mattia Russo Kirsty E. McGhee Tersilla Virgili David G. Lidzey Giulio Cerullo Margherita Maiuri 《Molecules (Basel, Switzerland)》2022,27(20)
Molecular dyes are finding more and more applications in photonics and quantum technologies, such as polaritonic optical microcavities, organic quantum batteries and single-photon emitters for quantum sensing and metrology. For all these applications, it is of crucial importance to characterize the dephasing mechanisms. In this work we use two-dimensional electronic spectroscopy (2DES) to study the temperature dependent dephasing processes in the prototypical organic dye Lumogen-F orange. We model the 2DES maps using the Bloch equations for a two-level system and obtain a dephasing time T2 = 53 fs at room temperature, which increases to T2 = 94 fs at 86 K. Furthermore, spectral diffusion processes are observed and modeled by a combination of underdamped and overdamped Brownian oscillators. Our results provide useful design parameters for advanced optoelectronic and photonic devices incorporating dye molecules. 相似文献