Long-time averaging for integrable Hamiltonian dynamics

Summary. Given a Hamiltonian dynamical system, we address the question of computing the limit of the time-average of an observable. For a completely integrable system, it is known that ergodicity can be characterized by a diophantine condition on its frequencies and that this limit coincides with the space-average over an invariant manifold. In this paper, we show that we can improve the rate of convergence upon using a filter function in the time-averages. We then show that this convergence persists when a symplectic numerical scheme is applied to the system, up to the order of the integrator.     

Use of polymeric nucleophiles for the selective binding and removal of α-methylene-γ-butyrolactone allergens from complex mixtures.

An insoluble polymer containing primary amines selectively removed α-methylene-γ-butyrolactone allergens from solutions.     

Etude en RMN du 13C des Effets de Substituant sur les Déplacements Chimiques du Carbone dans les Méthyl Tétrahydrofurannes

Carbon-13 nuclear magnetic resonance spectra have been recorded and interpreted for some methyltetrahydrofurans. The effects of a methyl substituent on the ring carbon atoms are discussed in terms of steric hindrance and conformational equilibrium.     

Probabilistic analysis of the subset-sum problem

Two linear time algorithms are shown to solve the n-object SUBSET-SUM problem with probability approaching 1 as n gets large, for a uniform instance distribution. Precise evaluations of the probabilities involved are given.     

Analyse conformationnelle de cétones cyclopropaniques par RMN à l'aide des déplacements paramagnétiques induits par Eu(dpm)3

The lanthanide induced shifts (LIS) of the lanthanide shift reagent Eu(dpm)₃ are reported for several cyclopropyl ketones. The conformational preference of the cyclopropanoyl group is determined via LIS by comparison with two compounds: dispiro-[2.1.2.2]nonane-4-one and 4,4,5-trimethyl bicyclo[3.1.0]hexane 2-one which are respectively in s-cis and s-trans conformation.     

Two-dimensional electron fluid at high temperature

The two-dimensional and one-component plasma (OCP) model withr ^?1 interactions is investigated in the high-temperature limit, where the thermal wavelength gets larger than the classical distance of closest approach. Nonnegligible diffraction effects are rigorously taken care of (up toe ²) through a temperature-dependent effective interaction. Debye thermodynamics, analyzed in terms of a classical plasma parameter Λ, is shown to diverge as Λ Inh, whenh→0. There is no classical limit. A result at variance with the corresponding one in three dimensions.     

Une algèbre graduée universelle pour les connexions sans torsion

Sans résumé