The mass spectrum of glycine

Irreproducibilities in the measurements of isotopic abundance in ¹⁵N labelled glycine have been related to the complex nature of chemical processes occurring during the evaporation of glycine prior to ionization.     

Photostablity and amplified spontaneous emission in dye-activated new organic-inorganic hybrid material

This paper reports on the lasing action of some dyes (pyrromethene 597, pyrromethene 567 and Rhodamin B) incorporated into a new organic-inorganic hybrid material. The amplified spontaneous emission (ASE) was studied under 532 nm, laser excitation in transverse pumping configuration for the prepared rod samples. The influence of the dye concentration on the amplified spontaneous emission peak wavelengths, the output energies, the gain and the energy conversion efficiencies were studied. Relatively high efficiencies (up to ∼64%) were obtained with good photostabilities where a decrease to ∼30% of the initial amplified spontaneous emission output energy were observed after pumping by 60,000 shots at relatively high repetition rate (10 Hz) and energy (15 mJ).     

Comparison between different data pre-treatment methods in the analysis of forage samples using near-infrared diffuse reflectance spectroscopy and partial least-squares multivariate calibration method

Moisture and protein content of alfalfa samples from Catalonia (Spain) have been analyzed by near-infrared (NIR) diffuse reflectance spectroscopy and multivariate calibration methods. In order to remove systematic variation in experimental data, such as base-line and multiplicative scatter effects, the evaluation of different data pre-processing methods is performed. Different figures of merit are used for quality assessment and comparison of these pre-treatment methods.     

Computational studies of 1:2 complex between retinol propionate and β cyclodextrin

[M05-2X/6-31G*:PM3MM] and [B3LYP/6-31G*:PM3] ONIOM2 methods have been used to investigate the vitamin A propionate/β cyclodextrin complex with 1:2 stoichiometry. Both methods give almost the same lowest energy minimum. The minimum energy structure of the complex is found in good agreement with experimental data. In this configuration, the major structure of propionate of vitamin A (PVA) is embedded inside the two cavities of βCD while the propionate group is kept outside. However, the three methyl groups of PVA are positioned in the free space between both βCD molecules. The driving forces for complexation are dominated by Van der Waals interactions between PVA and the βCD molecules assisted with multiple hydrogen bond interactions between the two cyclodextrin molecules. These interactions were investigated using the natural bond orbital approach.     

Pore water pressures in secondary consolidation

This paper describes the work carried out to investigate the pore pressures occurring in secondary consolidation. A theoretical approach and an experimental technique was developed in order to conduct the study.By considering compression to occur only due to water leaving the soil it was possible to derive an expression for the dissipation of pore pressure in the secondary phase. By further simplified assumptions which are based on experimental observations, the above general solution was reduced to a simple formula which predicted the observed behaviour of pore water pressures during secondary consolidation.     

The assessment of radiological risks associated with the ingestion of 210Po, 210Pb,and 137Cs in marine organisms collected from the local fish market of Kenitra,Morocco

Journal of Radioanalytical and Nuclear Chemistry - 210Po, 210Pb, and 137Cs activities were measured using gamma and alpha spectrometry in commonly consumed seafood collected from the local fish...     

Propagation of chaos for pressureless gas equations with viscosityPropagation du chaos pour un système de gaz sans pression avec viscosité

We use A.S. Sznitman ideas of probabilistic phenomenon of propagation of chaos for Burgers equation, and we derive the existence and uniqueness of a weak solution of the following system of pressureless gas equations with viscosity:

$\text{(}\text{S}\text{)}\text{?}\text{?t}\text{ρ+}\text{?}\text{?x}\text{(uρ)=}\text{1}\text{2}\text{?}{}^2\text{?}{}^2\text{x}\text{ρ,}\text{?}\text{?t}\text{(uρ)+}\text{?}\text{?x}\text{(u}{}^2\text{ρ)=}\text{1}\text{2}\text{?}{}^2\text{?}{}^2\text{x}\text{(uρ),}\text{ρ(}\text{d}\text{x,t)→ρ(}\text{d}\text{x,0),u(x,t)ρ(}\text{d}\text{x,t)→u}{}_0\text{(x)ρ(}\text{d}\text{x,0)}\text{weakly as}\text{t→0}{}^{\mathrm{+}}\text{.}$

To cite this article: A. Dermoune, C. R. Acad. Sci. Paris, Ser. I 335 (2002) 935–940.     

Spectrophotometric determination of microgram amounts of aromatic aldoximes with chloranil

Benzaldoxime and its p-hydroxy, methyl, chloro and nitro derivatives (50–500 μg) are determined by using chloranil as a π-acceptor at pH 9. The method is simple, precise (r.s.d. <3%) and accurate (±2%).     

Rhéologie particulière des solutions de polymères en millieus poreux

This paper describes the work carried out to investigate the pore pressures occurring in secondary consolidation. A theoretical approach and an experimental technique was developed in order to conduct the study. By considering compression to occur only due to water leaving the soil it was possible to derive an expression for the dissipation of pore pressure in the secondary phase. By further simplified assumptions which are based on experimental observations, the above general solution was reduced to a simple formula which predicted the observed behaviour of pore water pressures during secondary consolidation.     

Computation of normal forms of Hamiltonian systems in the presence of Poisson commuting integrals

The aim of this paper is to show the role of first integrals in further reducing the normal form unfolding of Hamiltonian systems. Based on a work by Cicogna and Gaeta, the joint normal form approach for Hamiltonian vector fields is considered. This normal form procedure, couched in a Lie-Poincaré scheme, allows us to see that we can reduce simultaneously the Hamiltonian together with its Poisson commuting integrals to a simplified normal form - a joint normal form - which is given a simple characterization. In this algorithmic procedure, approximate first integrals can be constructed (and used to simplify the normal form) at the same time that we bring the Hamiltonian to normal form. Further, following Walcher, we show that we can derive the joint normal form via a structure preserving transformation (in a sense to be specified). The approach is discussed from an implementational standpoint and illustrated by a Liouville-integrable Hénon-Heiles system. This revised version was published online in June 2006 with corrections to the Cover Date.