The reaction Yb+O2 → YbO + O in a crossed molecular beam experiment

Dissociation energy (D_o = 4.29 ± 0.05 eV), threshold energy (E = 0.83 ± 0.05 eV) and forward scattering at a collision-al energy E_c = 1.1 cV have been found by crossing beam of Yb atoms with a supersonic seeded beam of He + O₂ at collisional energies up to E_c = 1.4 eV.     

Cladding mode reorganization in high-refractive-index-coated long-period gratings: effects on the refractive-index sensitivity

We theoretically and experimentally investigated the reorganization of cladding modes in high-refractive-index- (HRI-) coated long-period gratings (LPGs), focusing on the influence of refractive-index sensitivity. When azimuthally symmetric nanoscale HRI coatings are deposited along LPG devices, a significant modification of the distribution of cladding modes occurs, depending on the layers' features (refractive index and thickness) and on the external refractive index. In particular, if these parameters are properly chosen, a transition between cladding modes and overlay modes occurs. Numerical and experimental effects of the mode transition on the sensitivity of the surrounding refractive index are described.     

Replication in Energy Markets: Use and Misuse of Chaos Tools

As pointed out by many researchers, replication plays a key role in the credibility of applied sciences and the confidence in all research findings. With regard, in particular, to energy finance and economics, replication papers are rare, probably because they are hampered by inaccessible data, but their aim is crucial. We consider two ways to avoid misleading results on the ostensible chaoticity of price series. The first one is represented by the proper mathematical definition of chaos and the related theoretical background, while the latter is represented by the hybrid approach that we propose here—i.e., consisting of considering the dynamical system underlying the price time series as a deterministic system with noise. We find that both chaotic and stochastic features coexist in the energy commodity markets, although the misuse of some tests in the established practice in the literature may say otherwise.     

Kinetic study on effect of novel cationic dimeric surfactants for the cleavage of carboxylate ester

Kinetic study has been performed to understand the reactivity of novel cationic gemini surfactants viz. alkanediyl‐α,ω‐bis(hydroxyethylmethylhexadecylammonium bromide) C₁₆‐s‐C₁₆ MEA, 2Br^? (where s = 4, 6) in the cleavage of p‐nitrophenyl benzoate (PNPB). Novel cationic gemini C₁₆‐s‐C₁₆ MEA, 2Br^? surfactants are efficient in promoting PNPB cleavage in presence of butane 2,3‐dione monoximate and N‐phenylbenzohydroxamate ions. Model calculation revealed that the higher catalytic effect of ethanol moiety of gemini surfactants (C₁₆H₃₃N⁺ C₂H₄OH CH₃ (CH₂)_S N⁺ C₂H₄OH CH₃C₁₆H₃₃, 2Br^?, s = 4, 6) is due to their higher binding capacity toward substrate. This is in line with finding that binding constants for novel series of cationic gemini surfactants are higher than conventional cationic gemini (C₁₆H₃₃N⁺(CH₃)₂(CH₂)_SN⁺(CH₃)₂C₁₆H₃₃, 2Br^?, s = 10, 12), cetyldimethylethanolammonium bromide and zwitterionic surfactants, i.e. C_nH_2n+1N⁺Me₂ (CH₂)₃ SO₃^? (n = 10; SB3‐10). The fitting of kinetic data was analyzed by the pseudophase model. Copyright © 2013 John Wiley & Sons, Ltd.     

A Novel Coherent Multilevel Combined Phase and Polarization Shift Keying Modulation in Twisted Fibers

This article proposes a novel coherent multilevel modulation model that exploits polarization and phase of the field. This model is based on the possibility of coherent systems to use all the four degrees of freedom of the electromagnetic field. The proposed scheme is able, by applying a suitable twisting process to the optical fiber, to physically confine the polarization and the phase of the transmitted field within the phase sphere. In this way, with the same performances of existing systems, the receiver is considerably simplified because there is no longer need of birefringence tracking circuits.     

Experimental study of a broad-band XeCl double-pass amplifier with SBS mirror

An oscillator-amplifier XeCl laser system has been used to experimentally investigate the effectiveness of a liquid stimulated Brillouin scattering (SBS) mirror for correcting the spatial aberrations of broad-band laser radiation in a double-pass amplifier. It has been found that the SBS amplifier performance is strongly dependent on the intensity I _p exciting the Brillouin medium. A good beam reconstruction has been attained at I _p1GW/cm², whereas highly aberrated output beams have been delivered by the SBS amplifier for I _p>1 GW/cm². By comparing the broad-band SBS amplifier performance to that of the same amplifier with a dielectrically coated flat mirror at one end, it has been found that the use of a SBS mirror is advantageous to obtain lower divergence output beams only for low energy pump beams (<1 mJ).     

An analyticity bound for two-dimensional Ising model at low temperature

We study the coexistence phase in the two-dimensional Ising model. Optimizing the cluster expansion technique, we are able to prove the phase separation phenomenon, with the Onsager value for the surface tension, in a range , where estimates from above the critical within 19% and essentially coincides with the entropic bound.     

On the Spectral Rigidity of Hopf Manifolds

We characterize Hopf manifolds of complex dimension 3 (resp. 2) in the class of compact locally conformal Kaehler manifold ( resp. Hermitian manifold ) by the spectrum of the Laplacian acting on functions.     

Design and performance of BOREAS,the beamline for resonant X‐ray absorption and scattering experiments at the ALBA synchrotron light source

The optical design of the BOREAS beamline operating at the ALBA synchrotron radiation facility is described. BOREAS is dedicated to resonant X‐ray absorption and scattering experiments using soft X‐rays, in an unusually extended photon energy range from 80 to above 4000 eV, and with full polarization control. Its optical scheme includes a fixed‐included‐angle, variable‐line‐spacing grating monochromator and a pair of refocusing mirrors, equipped with benders, in a Kirkpatrick–Baez arrangement. It is equipped with two end‐stations, one for X‐ray magnetic circular dichroism and the other for resonant magnetic scattering. The commissioning results show that the expected beamline performance is achieved both in terms of energy resolution and of photon flux at the sample position.     

Plume separation effect in pulsed laser ablation deposition

The results of a new geometrical configuration of pulsed laser ablation deposition technique that uses a hemi-cylindrical transparent plastic substrate are presented and discussed. With the new arrangement, two distinct components with different material compositions have been clearly observed. While the first component comprises atoms, ions and molecules and constitutes visible or the so-called luminous plume, the second component is formed of fragments, clusters and liquid droplets and is invisible to the naked eye. The latter component constitutes a major part of the ablated material. The luminous plume symmetry axis does not coincide with the mass distribution symmetry axis. In the case of Si ablation and 45° incident beam angle, the maximum deflection angle of the luminous plume reaches 30° with respect to the normal to the target surface, while the deflection angle of the second component is higher than 40°. The change in the target morphology and the dependence of the composition of the ablated material on local fluence, along with the hydrodynamic effects, is sought to explain this previously unexpected and unreported phenomenon. PACS 61.80.Ba; 47.35.+i; 52.38.Mf; 81.15.Fg