Mixing of electronic states in pentacene adsorption on copper

By combining experimental and theoretical approaches, we study the adsorption of pentacene on copper as a model for the coupling between aromatic molecules and metal surfaces. Our results for the interface electronic structure are not compatible with a purely physisorption picture, which is conventionally employed for such systems. Nay, we demonstrate electronic mixing between molecular orbitals and metal electronic states.     

Modification of surface properties of electrospun polyamide nanofibers by means of a perfluorinated acridine

Polyamide 6 (PA6) nanofibers were prepared from formic acid solutions by using electrospinning technique. The fibers were smooth, defects free and with diameters smaller than 200 nm. Small amounts of a perfluorinated acridine were added as dopant to the feed solution to modify the wettability of the fibers. The effect of doping on the contact angle values is well apparent. The contact angle values go from 50° of pure PA6 to 120° when 6% of acridine is added. A comparison between fibers and films of pure and doped polyamide 6 was carried out in order to determine the effect of morphology on wettability. Thermal annealing near the T_g of the polymer promoted the segregation of the molecules to the surface, reaching contact angles of 131° with smaller amounts (4%) of acridine. The surface segregation was also promoted by time aging.     

Comparison of Spaces of Hardy Type for the Ornstein–Uhlenbeck Operator

Denote by γ the Gauss measure on ℝ ⁿ and by ${\mathcal{L}}${\mathcal{L}} the Ornstein–Uhlenbeck operator. In this paper we introduce a Hardy space \mathfrakh¹g{{\mathfrak{h}}^1}{{\rm \gamma}} of Goldberg type and show that for each u in ℝ ∖ {0} and r > 0 the operator (rI+L)^iu(r{\mathcal{I}}+{\mathcal{L}})^{iu} is unbounded from \mathfrakh¹g{{\mathfrak{h}}^1}{{\rm \gamma}} to L ¹γ. This result is in sharp contrast both with the fact that (rI+L)^iu(r{\mathcal{I}}+{\mathcal{L}})^{iu} is bounded from H ¹γ to L ¹γ, where H ¹γ denotes the Hardy type space introduced in Mauceri and Meda (J Funct Anal 252:278–313, 2007), and with the fact that in the Euclidean case (rI-D)^iu(r{\mathcal{I}}-\Delta)^{iu} is bounded from the Goldberg space \mathfrakh¹\mathbbRⁿ{{\mathfrak{h}}^1}{{\mathbb{R}}^n} to L ¹ℝ ⁿ . We consider also the case of Riemannian manifolds M with Riemannian measure μ. We prove that, under certain geometric assumptions on M, an operator T{\mathcal{T}}, bounded on L ² μ, and with a kernel satisfying certain analytic assumptions, is bounded from H ¹ μ to L ¹ μ if and only if it is bounded from \mathfrakh¹m{{\mathfrak{h}}^1}{\mu} to L ¹ μ. Here H ¹ μ denotes the Hardy space introduced in Carbonaro et al. (Ann Sc Norm Super Pisa, 2009), and \mathfrakh¹m{{\mathfrak{h}}^1}{\mu} is defined in Section 4, and is equivalent to a space recently introduced by M. Taylor (J Geom Anal 19(1):137–190, 2009). The case of translation invariant operators on homogeneous trees is also considered.     

Kähler–Einstein submanifolds of the infinite dimensional projective space

This paper consists of two main results. In the first one we describe all Kähler immersions of a bounded symmetric domain into the infinite dimensional complex projective space in terms of the Wallach set of the domain. In the second one we exhibit an example of complete and non-homogeneous Kähler–Einstein metric with negative scalar curvature which admits a Kähler immersion into the infinite dimensional complex projective space.     

Stable isotope geochemistry of calcrete nodules and septarian concretions in a Quaternary 'red clay' paleovertisol from Hungary

Calcrete nodules and concretions in unusually large amounts are embedded in the Quaternary clay-rich (Vertisol-type) 'red clay' soil-sedimentary complex at the pediment of the Mátra Mountains (Hungary). Stable isotope signatures were studied in nodules and septarian concretions, uncommon due to their several millimeter sized calcite crystals filling voids and fractures, to reveal their origin. The isotope composition of calcrete covers a wide range: delta18O=-5.9 to-10.4 per thousand and delta13C=-8.9 to-12.3 per thousand (vs. V-PDB). Isotope compositions support pedogenic (sensu stricto) and/or shallow groundwater origin for the calcrete nodules and concretions, the role of 'evolved' (isotopically modified) groundwaters in the formation of secondary carbonate was possibly subordinate. Late-stage, large, Mn-rich euhedral calcite crystals in concretions have the lowest delta13C values, which are interpreted as a result of larger contribution of isotopically light organic carbon due to decomposition of organic matter under reducing conditions. Precipitation of late calcite crystals in concretions occurred in early diagenetic environment after shallow burial of the 'red clay' paleovertisol.     

Acoustic waveguide filters made up of rigid stacked materials with elastic joints

Meccanica - The acoustic dispersion properties of monodimensional waveguide filters can be assessed by means of the simple prototypical mechanical system made of an infinite stack of periodic...     

A novel statistical linearization solution for randomly excited coupled bending-torsional beams resting on non-linear supports

A novel statistical linearization technique is developed for computing stationary response statistics of randomly excited coupled bending-torsional beams resting on non-linear elastic supports. The key point of the proposed technique consists in representing the non-linear coupled response in terms of constrained linear modes. The resulting set of non-linear equations governing the modal amplitudes is then replaced by an equivalent linear one via a classical statistical error minimization procedure, which provides algebraic non-linear equations for the second-order statistics of the beam response, readily solved by a simple iterative scheme. Data from Monte Carlo simulations, generated by a pertinent boundary integral method in conjunction with a Newmark numerical integration scheme, are used as benchmark solutions to check accuracy and reliability of the proposed statistical linearization technique.