Optical lattice trapping of 199Hg and determination of the magic wavelength for the ultraviolet 1S(0)↔3P(0) clock transition

We report on the Lamb-Dicke spectroscopy of the doubly forbidden (6s(2))(1)S(0)?(6s6p)(3)P(0) transition in (199)Hg atoms confined to a vertical 1D optical lattice. With lattice trapping of ?10(3) atoms and a 265.6 nm probe laser linked to the LNE-SYRTE primary frequency reference we have determined the center frequency of the transition for a range of lattice wavelengths and at two lattice trap depths. We find the Stark-free (magic) wavelength to be 362.53(0.21) nm-essential knowledge for future use of this line in a clock with anticipated 10(-18) range accuracy. We also present evidence of the laser excitation of a Wannier-Stark ladder of states in a lattice of well depth 10E(R).     

A Line-Search Algorithm Inspired by the Adaptive Cubic Regularization Framework and Complexity Analysis

Adaptive regularized framework using cubics has emerged as an alternative to line-search and trust-region algorithms for smooth nonconvex optimization, with an optimal complexity among second-order methods. In this paper, we propose and analyze the use of an iteration dependent scaled norm in the adaptive regularized framework using cubics. Within such a scaled norm, the obtained method behaves as a line-search algorithm along the quasi-Newton direction with a special backtracking strategy. Under appropriate assumptions, the new algorithm enjoys the same convergence and complexity properties as adaptive regularized algorithm using cubics. The complexity for finding an approximate first-order stationary point can be improved to be optimal whenever a second-order version of the proposed algorithm is regarded. In a similar way, using the same scaled norm to define the trust-region neighborhood, we show that the trust-region algorithm behaves as a line-search algorithm. The good potential of the obtained algorithms is shown on a set of large-scale optimization problems.     

Sur la répartition des diamants dans un tournoi

A tournament T=(V,A) is a directed graph such that for every x,y∈V, where x≠y, (x,y)∈A if and only if (y,x)?A. For example, the 3-cycle is the tournament ({1,2,3}, {(1,2),(2,3),(3,1)}). Up to an isomorphism, there are two tournaments with 4 vertices and containing an unique 3-cycle which we call diamonds. We prove that for any tournament T defined on n?9 vertices, either T contains at least 2n?6 diamonds or the number of diamonds contained in T is equal to 0, n?3 or 2n?8. Following the characterization of the tournaments without diamonds due to Gnanvo and Ille (Z. Math. Logik Grundlag. Math. 38 (1992) 283–291) and to Lopez and Rauzy (Z. Math. Logik Grundlag. Math. 38 (1992) 27–37), we study the morphology of the tournaments defined on n?5 vertices and which contain exactly n?3 or 2n?8 diamonds. To cite this article: H. Bouchaala, C. R. Acad. Sci. Paris, Ser. I 338 (2004).     

Existentially closed CSA-groups

We study existentially closed CSA-groups. We prove that existentially closed CSA-groups without involutions are simple and divisible, and that their maximal abelian subgroups are conjugate. We also prove that every countable CSA-group without involutions embeds into a finitely generated one having, up to conjugacy, the same maximal abelian subgroups, except maybe the infinite cyclic ones. We deduce from this that there exist 2^₀ countable existentially closed CSA-groups without involutions and that their first-order theories have 2^₀ types over .     

Sol–gel synthesis of ZnO–SiO2 thin films: impact of ZnO contents on its photonic efficiency

Highly crystalline ZnO–SiO₂ films obtained by a sol–gel method at different ZnO contents were deposited on silicon substrate (P(100)) using spin coating process. The XRD results revealed that the strong ZnO(100) peak is grown with highly c-axis oriented film and the crystallinity is progressively improved with increasing ZnO contents. SEM micrographs of the films deposited on silicon substrate show a homogeneous and uniformity structure at different ZnO content. The prepared ZnO–SiO₂ films are compared with either a film prepared from a commercial photocatalysts Hombikat UV-100 or Pilkington Glass Activ? by the determination of their photonic efficiencies for degradation of methylene blue. The photocatalytic efficiency of the 10 wt% ZnO–SiO₂ film was found to be about four times higher than film prepared from UV-100 or Pilkington Glass Activ?. The photocatalytic efficiencies of ZnO–SiO₂ films are increased with increasing ZnO content from 1 wt% to 10 wt% ZnO and then decreased at 15 wt% ZnO. The order of photocatalytic efficiencies of ZnO–SiO₂ films at different ZnO content and commercial photocatalysts after 6 h illumination were as following: 10 wt% ZnO > 15 wt% ZnO > 1 wt% ZnO > as-prepared 10 wt% ZnO–SiO₂ film > UV-100 > Pilkington Glass Activ?, which suggested that the ZnO–SiO₂ films are photoactive than commercial photocatalysts. The improved efficiency and potentially the low-cost synthesis suggest that this material might be practically useful as a photocatalyst film.     

Purification and Partial Characterization of Peroxidases from Three Food Waste By-Products: Broad Bean Pods,Pea Pods,and Artichoke Stems

Applied Biochemistry and Biotechnology - In this study, peroxidases (PODs) from three waste by-products: broad bean pods (BBP), pea pods (PP), and artichoke stems (ARS) were purified and their...     

Shifts of one-electron ions lines from n = 0 interactions with electrons in hot and dense plasma

This paper is concerned with lineshifts of hydrogen-like ions due to electron collisions in dense and hot plasmas. These collisions are treated by including all effects due to monopole, dipole, and quadrupole interactions between radiator and electron perturbers. The latter follow exact hyperbolic trajectories with a possible penetrating part inside atomic orbits. A simple closed form for the line shift has been derived. Comparison between our semi-classical results and the quantum mechanical ones shows good agreement for a large range of high electron densities and temperatures. Received: 30 June 1997 / Revised: 28 April 1998 / Accepted: 29 April 1998