Identification et Etude en Résonance Magnétique Nucléaire du Carbone-13 des Produits de la Réaction de Quaternisation en Série Thiazolo[3,2-d]tétrazolique

We have demonstrated that the compounds obtained by quaternization of thiazolo[3,2-d]tetrazole, and two of its derivatives, 3-phenyl-thiazolo[3,2-d]tetrazole and tetrazolo[5,1-b]benzothiazole, are tetrazolium salts. The quaternization effects are discussed as a function of the ¹³C NMR results.     

Study of the γD → ppπ− reaction in the Δ(1236) region for well defined kinematical conditions

The γD → ppπ^? reaction cross section, in the Δ(1236) region, is measured in a counter experiment with high statistical accuracy. Particular emphasis is put on the accurate determination of the complete kinematics. For low values of the undetected nucleon momentum (p_r, ≈ 50 MeV/c), the validity of the spectator nucleon model is experimentally checked and the γn → pπ^? elementary reaction cross section is extracted and compared with other experimental data. When the recoiling nucleon momentum increases (p_r ≈ 150 MeV/c), significant departures from the spectator nucleon model are found. Presumably they are the signature of final state interaction effects.     

A study of the reaction 2H(π±, p)X

We have studied the excitation function of the reaction ²H(π^±, p)X at a fixed proton angle of 90° for several fixed proton momenta of the detected proton as a function of the incident pion energy. No signal was found for a previous candidate for a dibaryon resonance around a mass of 2.23 GeV. The general trend of the data is reproduced by a multiple scattering theory     

Effect of instrumental particle sizing resolution on the modelling of aerosol radiative parameters

A more realistic estimation of the scattering and hemispheric backscattering coefficients, σ_sp and σ_bsp, and their respective optical cross section, C_sca and C_bk, of aerosol particles is presented on the basis of the exact resolution of the width of the size bins of the particle counter instruments when size distribution measurements are used, and, with the exact optical detector instruments ability. The scattering and hemispheric backscattering cross sections, C_sca and C_bk, of the particles are averaged over the full size bins of the particle counter instrument, while these quantities are usually estimated only on the value of the mean geometric diameter of each size bin. Six instruments, the APS, ASASP-X, DMPS, FSSP-100, ELPI, and SMPS frequently used in particle size distribution measurements are reviewed, for spherical sea-salt particles at a wavelength λ=0.55 μm. The comparison using the conventional geometric mean diameter versus the use of the full size bin leads to large amount of errors for the optical cross section with non-negligible effects on their respective optical coefficients. The maximal accuracy expected for these optical quantities depend on the particle diameter as well as on the channel width of the instruments, and are also function of the angular detector probe used to measure them.     

Procedure of test to compare the tail indices

We propose a test procedure which compares the extreme value indices of two samples with heavy tail distributions. On a theoretical point of view, we adopt the minimax nonparametric point of view. We exhibit the separating rate between the null hypothesis and the alternative of our procedure. Next, we present a data driven test methodology and we evaluate its performance thanks to an extensive simulation study. As a practical real-life application, we compare the risk behaviors of a panel of different financial data.     

Instant controlled pressure drop technology and ultrasound assisted extraction for sequential extraction of essential oil and antioxidants

The instant controlled pressure drop (DIC) technology enabled both the extraction of essential oil and the expansion of the matrix itself which improved solvent extraction. The sequential use of DIC and Ultrasound Assisted Extraction (UAE) triggered complementary actions materialized by supplementary effects. We visualized these combination impacts by comparing them to standard techniques: Hydrodistillation (HD) and Solvent Extraction (SE). First, the extraction of orange peel Essential Oils (EO) was achieved by HD during 4 h and DIC process (after optimization) during 2 min; EO yields was 1.97 mg/g dry material (dm) with HD compared to 16.57 mg/g dm with DIC. Second, the solid residue was recovered to extract antioxidant compounds (naringin and hesperidin) by SE and UAE. Scanning electron microscope showed that after HD the recovered solid shriveled as opposite to DIC treatment which expanded the product structure. HPLC analyses showed that the best kinetics and yields of naringin and hesperidin extraction was when DIC and UAE are combined. Indeed, after 1 h of extraction, DIC treated orange peels with UAE were 0.825 ± 1.6 × 10^?2 g/g of dry material (dm) for hesperidin and 6.45 × 10^?2 ± 2.3 × 10^?4 g/g dm for naringin compared to 0.64 ± 2.7 × 10^?2 g/g of dry material (dm) and 5.7 × 10^?2 ± 1.6 × 10^?3 g/g dm, respectively with SE. By combining DIC to UAE, it was possible to enhance kinetics and yields of antioxidant extraction.     

Method for detecting and characterising actinide-bearing micro-particles in soils and sediment of the Fukushima Prefecture,Japan

An aqueous biphasic system has been used for selective extraction of U(VI) ions from Th(IV), Sm(III) and Ce(III). Role of different biomolecules like morin, catechin, hesperidin and 4-hydroxycoumarin have been studied. Morin serves as the best reagent when citrate ions are used as a masking agent. Citrate forms stronger complexes with the other metal ions than morin thereby restricting their extractions. Contrarily, U(VI) forms a stronger complex with morin than citrate and is selectively extracted under the same conditions. It was also observed that morin can act as a spectrophotometric reagent for ratiometric detection and analysis of U(VI) ions.

     

Probing complex materials with coherent soft X-rays

We motivate the use of coherent soft X-ray beams to study materials that exhibit complex nanoscale behaviors. A new beamline and magnetic scattering end station that has been constructed and commissioned at the ALS will be described. Finally, we present some initial results that indicate the performance of the beamline. K. Chesnel now at Department of Physics, Brigham Young University, Provo, Utah, USA. J.J. Turner now at Department of Physics, Stony Brook University, Stony Brook, New York, USA. M. Pfeifer now at School of Physics La Trobe University, Melbourne, Australia.     

Thulium environment in a silica doped optical fibre

Thulium-doped optical fibre amplifiers (TDFA) are developed to extend the optical telecommunication wavelength division multiplexing (WDM) bandwidth in the so-called S-band (1460–1530 nm). The radiative transition at 1.47 μm (³H₄ → ³F₄) competes with a non-radiative multi-phonon de-excitation (³H₄ → ³H₅). The quantum efficiency of the transition of interest is then highly affected by the phonon energy (E_p) of the material. For reliability reasons, oxide glasses are preferred but suffer from high phonon energy. In the case of silica glass, E_p is around 1100 cm^?1 and quantum efficiency is as low as 2%. To improve it, phonon energy in the thulium environment must be lowered. For that reason, aluminium is added and we explore three different core compositions: pure silica, and silica slightly modified with germanium or phosphorus. The role of aluminium is studied through fluorescence decay curves, fitted according to the continuous function decay analysis. From this analysis, modification of the thulium local environment due to aluminium is evidenced.     

Adaptive estimation of the stationary density of a stochastic differential equation driven by a fractional Brownian motion

Statistical Inference for Stochastic Processes - We build and study a data-driven procedure for the estimation of the stationary density f of an additive fractional SDE. To this end, we also prove...