Development of an apparatus for obtaining molecular beams in the energy range from 2 to 200 eV

The formation and detection of molecular beams obtained by charge exchange from a low-energy ion source is discussed. Dispersion in energy of the ion source was measured and problems concerning detection of neutral beams were studied. Various methods were used, specifically secondary electron emissivity of a metallic surface and ionization of a gas target with a low ionization voltage. The intensities of neutral beams as low as 10 eV are measured by a tubular electron multiplier and a lock-in amplifier

Nuclear Interactions of 400 GeV Protons in Emulsion

We report on 400 GeV proton-emulsion nucleus reactions and compare the results to hadron-nucleus reactions at smaller energies. In particular we present results on the emission of fast target protons (essentially grey track particles) and on their correlation with the number of collisions inside the nucleus, ν, with the number of charged evaporated particles (essentially black track particles) and with the number of pions produced (essentially shower particles). We observe that the main features of the 200¿400 GeV data are very similar. However, we find that the mean shower-particle multiplicity at 400 GeV is essentially higher than expected from the simple independent particle model prediction 〈ns〉 = 〈nch〉[1 + 0.5(〈ν〉 − 1)]. The shower particle multiplicities do not seem to follow a target mass dependence of the form 〈ns〉 = 〈nch〉 Aα with α = 0.14 or α = 0.19 as has been suggested in the literature. The pseudo-rapidity distribution shows limiting target and projectile fragmentation. The shower-particle multiplicity in the ¿central region¿ increases linearity with 〈ν〉 but faster than 0.5〈ν〉 times the corresponding multiplicity in pp reactions

Synthesis, characterization and antibacterial activity studies of new 2‑pyrral‑L‑amino acid Schif base palladium (II) complexes.

Three new 2-pyrral amino acid Schif base palladium (II) complexes were synthesized, characterized and their activity against six bacterial species was investigated. The ligands: Potassium 2-pyrrolidine-L-methioninate (L1), Potassium 2-pyrrolidine-L-histidinate (L2) and Potassium 2-pyrrolidine-L-tryptophanate (L3) were synthesized and reacted with dichloro(1,5- cyclooctadiene)palladium(II) to form new palladium (II) complexes C1, C2 and C3, respectively. 1 NMR, FTIR, UV–Vis,elemental analysis and conductivity measurements were used to characterize the products. The antibacterial activities of the compounds were evaluated against Gram-positive Staphylococcus aureus (S. aureus, ATCC 25923), methicillin-resistant Staphylococcus aureus (MRSA, ATCC 33591), Staphylococcus epidermidis (S. epidermidis, ATCC 12228) and Streptococcus pyogenes (S. pyogenes, ATCC 19615) and, gram-negative Pseudomonas aeruginosa (P. aeruginosa, ATCC 27853) and Klebsiella pneumoniae (K. pneumoniae, ATCC 13883) using the agar well difusion assay and microtitre plate serial dilution method. The palladium complexes were active against the selected bacteria with the imidazole ring containing complex C2 and indole heterocyclic ring containing complex C3 showing the highest activity

Caractérisation d'oligopeptide de l'acide α-L-glutamique par spectrométrie de masse FAB--MBSA/CID--MIKE

International audienc

Propositional Tree Automata

In the paper, we introduce a new tree automata framework, called propositional tree automata, capturing the class of tree languages that are closed under an equational theory and Boolean operations. This framework originates in work on developing a sufficient completeness checker for specifications with rewriting modulo an equational theory. Propositional tree automata recognize regular equational tree languages. However, unlike regular equational tree automata, the class of propositional tree automata is closed under Boolean operations. This extra expressiveness does not affect the decidability of the membership problem. This paper also analyzes in detail the emptiness problem for propositional tree automata with associative theories. Though undecidable in general, we present a semi-algorithm for checking emptiness based on machine learning that we have found useful in practice

Transition vers la turbulence pour un fluide rhéofluidifiant en écoulement dans une conduite cylindrique

International audienceLa transition vers la turbulence en conduite cylindrique pour des fluides non-Newtoniens dont le caractère rhéofluidifiant est suffisamment marqué se caractérise par l'apparition d'un régime non linéaire asymétrique avant l'apparition des spots classiques de turbulence ''puffs'' [1,2,3]. Dans ce régime non linéaire asymétrique, les profils de vitesse axiale mesurés par LDA présentent une asymétrie croissante avec le nombre de Reynolds et avec la position axiale mesurée à partir de l'entrée. Cette asymétrie se caractérise par l'existence dans une section de la conduite d'une zone de survitesse et d'une zone de sous-vitesse. Dans la présente communication, nous présentons de nouveaux résultats expérimentaux sur la structure de l'écoulement obtenus par PIV 2D. L'analyse des profils de vitesse axiale mesurés à différents instants montre que cette asymétrie n'est pas stationnaire. Dans une section de la conduite, la position azimutale de la zone de survitesse évolue au cours du temps. Un post-traitement par décomposition en modes propres orthogonaux (POD) est développé pour mettre en évidence les caractéristiques énergétiques principales du régime non linéaire asymétrique. Abstract : The transition to turbulence in a cylindrical pipe of non-Newtonian fluids for which the shear-thinning behavior is sufficiently strong is characterized by the appearance of a nonlinear asymmetric state before the observation of turbulent spots (puffs) [1,2,3]. In this nonlinear asymmetric regime, the axial velocity profiles measured with LDA exhibit an increasing asymmetry with increasing the Reynolds number and with increasing the axial position from the entrance. This asymmetry of the time-averaged axial velocity profiles is described in terms of low and fast streaks. In this communication, new experimental results obtained using 2D PIV are presented. The analysis of the axial velocity profiles at different times show that this asymmetry is not stationary. For a given axial location, the azimuthal position of the high/low h streaks evolve with time. A post-processing based on Proper Orthogonal Decomposition of eigen-modes in order to highlight the most energetic modes

BHDL: circuit design in B

International audienc