Search results for "SPLIT"

Analysis of the angular acceptance of surface plasmon Bragg mirrors

2007

International audience; We analyze an important aspect of the behavior of surface plasmon polariton (SPP) Bragg mirrors: the dependence of the angular acceptance for reflection on the incidence angle. By means of leakage radiation microscopy, both in direct and Fourier space, we observe that the angular acceptance diminishes for increasing incidence angles. This effect, which can considerably affect the design of devices based on these elements, is shown to be the consequence of the decrease of the bandgap width with increasing incidence angle. (c) 2007 Optical Society of America.

Excitons in few-layer hexagonal boron nitride: Davydov splitting and surface localization

2018

Hexagonal boron nitride (hBN) has been attracting great attention because of its strong excitonic effects. Taking into account few-layer systems, we investigate theoretically the effects of the number of layers on quasiparticle energies, absorption spectra, and excitonic states, placing particular focus on the Davydov splitting of the lowest bound excitons. We describe how the inter-layer interaction as well as the variation in electronic screening as a function of layer number $N$ affects the electronic and optical properties. Using both \textit{ab initio} simulations and a tight-binding model for an effective Hamiltonian describing the excitons, we characterize in detail the symmetry of t…

Unaccusativity

2012

Abstract My research is an attempt at suggesting a cross-linguistically valid definition of verbs characterized by unagentivity and affectedness such as “burn”, “die”, “sink”, “fall”, “slide”, etc., which according to the present analysis constitute the semantic core of unaccusativity. Both synchronic and diachronic approaches are followed. Various definitions have been attributed to these verbs (eventives, anticausatives, transformatives, inchoatives, decausatives). Although Perlmutter & Postal (1984) classify unaccusative verbs on the basis of their syntactic behavior, they also argue that the syntactic expression of arguments is always determinable on the basis of the meaning of the verb…

Nanostructured Nickel alloy electrodes for alkaline electrolysers

The evolutionary dynamics of adaptive virginity, sex-allocation and altruistic helping in haplodiploid animals

2018

In haplodiploids, females can produce sons from unfertilized eggs without mating. However, virgin reproduction is usually considered to be a result of a failure to mate, rather than an adaptation. Here, we build an analytical model for evolution of virgin reproduction, sex-allocation, and altruistic female helping in haplodiploid taxa. We show that when mating is costly (e.g., when mating increases predation risk), virginity can evolve as an adaptive female reproductive strategy. Furthermore, adaptive virginity results in strongly divergent sex-ratios in mated and virgin queen nests ("split sex ratios"), which promotes the evolution of altruistic helping by daughters in mated queen nests. H…

Cubane-Type Mo3CoS4 Molecular Clusters with Three Different Metal Electron Populations: Structure, Reactivity and Their Use in the Synthesis of Hybri…

2004

Heterodimetallic cubane-type complexes coordinated to diphosphanes [Mo(3)CoS(4)(dmpe)(3)Cl(4)](+) ([1](+)) (dmpe=1,2-bis(dimethylphosphanyl)ethane), [Mo(3)CoS(4)(dmpe)(3)Cl(4)] (1) and [Mo(3)CoS(4)(dmpe)(3)Cl(3)(CO)] (2) with 14, 15 and 16 metal electrons, respectively, have been prepared from the [Mo(3)S(4)(dmpe)(3)Cl(3)](+) trinuclear precursor using [Co(2)(CO)(8)] or CoCl(2) as cobalt source. Cluster complexes [1](+) and 1 are easily interconverted chemically and electrochemically. The Co-Cl distance increases upon electron addition and substitution of the chlorine atom coordinated to cobalt with CO only takes place in presence of a reducing agent to give complex 2. Structural changes in…

Fractional-Fourier-transform calculation through the fast-Fourier-transform algorithm.

1996

A method for the calculation of the fractional Fourier transform (FRT) by means of the fast Fourier transform (FFT) algorithm is presented. The process involves mainly two FFT’s in cascade; thus the process has the same complexity as this algorithm. The method is valid for fractional orders varying from −1 to 1. Scaling factors for the FRT and Fresnel diffraction when calculated through the FFT are discussed.

The Role of the Integrated Public Transport Network for Reducing the Congestion in the City of Palermo

2019

The railway link of Palermo is part of the Palermo – Trapani railway line and it is located in the urban site of Palermo. Works funded by the European Union have been started in 2008 for developing a metropolitan service through the improvement of the infrastructure and of the transport service characteristics. The aim of the paper is the analysis of the capacity of the railway infrastructure in terms of frequency and integration with the public transport service of Palermo. Using the Origin-Destination matrix of the Urban Transport Plan of Palermo, the competition between the private car mode and the public transport mode has been simulated, taking into account the improving of the railway…

Interactions of organotins with biological systems

1992

The bonding and structure in the environments of tin atoms in organotin-biological molecules has been investigated by 119Sn Mossbauer spectroscopy, mainly through the rationalization of the nuclear quadrupole splitting parameter by pointcharge model approaches. Organotin moieties R2SnIV and R3SnIV (R = Me, nBu, Ph) generally assume trigonal-bipyramidal type configurations in membranes of human erythrocytes, when incubated with whole erythrocytes and erythrocyte ghosts at the level of micromolar (μmol dm−3) organotin per mg of membrane protein. Corresponding structures are assumed by Me2SnIV and Me3SnIV in the cytoplasm. Ethanolic Me2SnCl2 yielded distorted trans-octahedral species when reac…

119Sn Mössbauer spectroscopic studies of the products of the reaction of triorganotin(IV) derivatives with 6-thiopurine

1985

Abstract A structural study of the products of the reaction of R 3 Sn IV derivatives (R = Me, Bu n , Ph) with 6-thiopurine, 6-TPH 2 , and its sodium salt, 6-TPHNa, has been undertaken using Mossbauer spectroscopy and the point-charge model rationalization of the Mossbauer parameter nuclear quadrupole splitting. The synthetic reactions have been carried out at ca . 0 °C, 20 °C and 50 °C. The Mossbauer spectra of the complexes AlK 3 Sn(6-TPH) are consistent with the occurrence of two distinct tin(IV) sites in samples prepared at the lower temperature, while one only site appears by increasing the temperature of the reaction. Two tin sites constantly occur in the products of the reactions invo…