Angular correlation measurements in the B10(d,p,γ)B11 reaction

Proton gamma angular correlations through the 6.76 and 8.92 MeV excited states of B¹¹ are measured at deuteron bombarding energies from 1.6 to 2.4 MeV. The correlations are measured at laboratory proton scattering angles 35? in both reaction and azimuthal planes. The correlation coefficientA ₂ ⁰ and the distortion parameterλ are calculated. A systematic shift of the symmetry axis from the recoil direction is observed. This shift tends to zero asE _d→Q. For the 8.92 MeV excited state of B¹¹(Q=0.32 MeV) the distortion parameterλ is close to the plane wave limit. The possible values of incoming channel spins as well as gamma-ray multipole mixing ratio for the 6.76 and 8.92 MeV states are obtained.     

Angular correlation measurement in the B11(d,pγ)B12 reaction

Thep-γ angular correlations in B¹¹(d, p)B¹² reaction have been measured in both reaction and azimuthal planes for proton angles 35° at E_D=1.60 and 2.40 MeV. The correlation coefficient A ₂ ⁰ and the distortion parameterλ were calculated. The obtained values of the shift of the symmetry axis from the recoil direction, Φ₀ and the parameterλ are far from there plane wave limits. The anisotropy of the angular correlation gives two possible values, 1⁺ and 2⁺, for the spin of the first excited state of B¹².     

Determination of uranium and radium in phosphate rock and technical phosphoric acid

Summary Uranium in phosphate rock can be determined radiometrically using gamma-counting and spectrophotometrically using arsenazo I. In the latter case the rock is dissolved in HNO₃, then uranium is extracted with tributyl phosphate, stripped with hot water and determined. For the determination of uranium in technical phosphoric acid, the fluorosilicate ion present as impurity must first be precipitated, the uranium separated on Amberlite IRA-400 in the sulfate form, then determined in the eluate spectrophotometrically by arsenazo I. Radium can be determined in leach solutions by the emanation method.

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Bestimmung von Uran und Radium in Phosphatgestein und technischer Phosphorsäure

Zusammenfassung Uran kann in Phosphatgestein radiometrisch mit -Zählung und spektralphotometrisch mit Arsenazo I bestimmt werden. Zur spektralphotometrischen Bestimmung wird die Probe in Salpetersäure gelöst, dann das Uran mit Tributylphosphat extrahiert, in heißes Wasser überführt und bestimmt. Zur Uranbestimmung in technischer Phosphorsäure muß zuerst das als Verunreinigung vorhandene Fluorosilicat gefällt und dann das Uran mit Hilfe von Amberlit IRA-400 in der Sulfatform abgetrennt werden, bevor es im Eluat mit Arsenazo I bestimmt werden kann. Radium kann in Auslaugungslösungen mit Hilfe der Emanationsmethode bestimmt werden.

     

The control of lightning using lasers: properties of streamers and leaders in the presence of laser-produced ionization

This paper summarizes the research this team has performed over the past few years investigating laboratory electrical breakdown discharges in the presence of a plasma cylinder created by a single ultrashort laser pulse. This work is part of a feasibility study about the control of lightning using laser systems. Our experimental investigations have included discharges (i) in modest (30 cm) air gaps mediated by streamers, and (ii) in large (several meters) ambient air gaps for which the discharge took place through the formation of a leader, the mechanism relevant to large scale natural discharges such as lightning. In order to understand the observations, various physical models have been used, the main results of which are discussed in this paper. To cite this article: F. Vidal et al., C. R. Physique 3 (2002) 1361–1374.     

Nucleophilic addition to the tricarbonyl(η-cycloheptadienylium)iron cation by alkoxide ions. Formation of carboalkoxy intermediates

Nucleophilic addition the title compound by alkoxide ions (OR^?) at 0°C proceeds via a red intermediate probably involving metal-nucleophile interaction, and subsequent formation of the carboalkoxy compound C₇H₉Fe(CO)₂(CO₂R). On raising the temperature, the latter compound rearranges spontaneously by a dissociative mechanism to give the corresponding 5-exo-ring compound C₇H₉ORFe(CO)₃.     

Separation and quantification by high-performance liquid chromatography with light scattering detection of the main wheat flour phospholipids during dough mixing in the presence of phospholipase

Phospholipids (PL) are minor components of wheat flour involved in baking quality and exogenous phospholipids are used as emulsifiers giving better loaf volume and crumb grain. Few biochemical data are available on the phospholipid evolution during mixing, probably because of the time-consuming methods proposed for their extraction, separation and quantification. In the present study, the extraction, separation and quantification of the main wheat flour phospholipids were carried out. Total lipids (2% dry mass of wheat flour) were extracted from flour or dough by a mixture of chloroform-methanol-water (1:1:1 (v/v)). The phospholipids were separated from the lipid extract on silica cartridge by solid-phase extraction (SPE) procedure under a 1.5-4 mmHg vacuum, at a 0.8 mL min(-1) flow rate (1 mmHg = 133.322 Pa). The recovery of the lipid extract was 100%, whereas the SPE yield for the PLs was 50%. The resulting fraction was then submitted to HPLC with evaporative light scattering detection on a Diol stationary phase allowing the separation and quantification of each class of phospholipids, in less than 16 min. The developed method allowed to quantify the phospholipid amounts from eight wheat flours as well as their evolution during mixing in the presence of phospholipase.     

Optimization of the preparation conditions of radioiodoepidepride: A dopamine D<Subscript>2</Subscript>receptor antagonist radioligand

Summary [¹²⁵I]iodepidepride, (s)-(-)-[(1-ethyl-2-pyrrolidinyl)methyl]-5-[¹²⁵I]-iodo-2,3-dimethoxybenzamide is the iodine substituted analogue of isoremoxipride, both of which are very potent dopamine D₂-antagonists. Epidepride was radioiodinated using different oxidizing agents such as chloramine-T, iodogen, iodogen glass frit and hydrogen peroxide. Chloramine-T is a powerful oxidizing agent compared to both iodogen and hydrogen peroxide so that the side products, especially the chlorinated epidepride, decreases the radiochemical yield. This chlorinated epidepride is minimized in the case of iodogen and iodogen glass frit and are not observed in case of the non-chlorinated oxidizing agent hydrogen peroxide. TLC and HPLC were used to analyze the reaction components and to estimate both the radiochemical yield and purity. The reaction parameters such as reaction time, pH, epidepride and oxidizing agent concentrations and the stabilty of the final product were studied to optimize the radiochemical yield and purity. The optimized radiochemical yield was about 90% and the radiochemical purity of the final product was 99.9%.     

Solvent Extraction of Ag(I) and Cu(II) with New Macrocyclic Schiff Bases

Two new macrocyclic Schiff bases (II) and (III) containing nitrogen ‐ oxygen donor atoms were synthesized by reaction between diethylene triamine or 2,2′‐(ethylenedioxy)bis(ethylamine) and the intermediate compound: 1,4‐bis(6‐methoxy‐2‐formylphenyl)‐1,4‐dioxabutane (I). Identification of these macrocyclic Schiff bases: 1,12, 15,18, 29,32 ‐ hexaaza ‐ [3,4;8,9;20,21;26,27‐tetra‐(6′‐methoxyphenyl)]‐5,8,22,25‐tetraoxa cyclo tetratriacosine‐1,11,18,28‐tetraene. (II) 1,12,21,32‐tetraaza‐[3,4;9,10;23,24;29, 30‐tetra‐(6′‐methoxyphenyl)]‐5,8,15,18,25,28,35,38‐octaoxa cyclo ‐ tetracontane‐1,11,21,31‐tetraene. (III) were determined by elemental analysis (LC‐MS), (IR) and (¹H and ¹³C‐NMR) spectroscopy. The liquid‐liquid extraction of metal picrates such as Ag⁺ and Cu²⁺ from aqueous phase to organic phase was carried out using these ligands. The effect of chloroform and dichloromethane as organic solvents over the metal picrate extractions were investigated at 25 ± 0.1 °C by using atomic absorption spectrometer.