For England everything centres round India and Arabia » La guerre anglo-allemande dans le golfe Persique : impérialismes, politique tribale et jihad (1914-1915)

Résumé : Plusieurs études ont été consacrées à la grande révolte du Hedjaz contre le joug ottoman durant l’année 1916 ou à celle des tribus d’Irak contre les Britanniques après 1919. Cet article revient sur un épisode trop peu connu de l’histoire de la Première Guerre mondiale au Moyen-Orient : le soulèvement de plusieurs "tribus" de Perse et du Golfe en 1915. Il démontre comment cette révolte fut fortement soutenue par Berlin et l’empereur Guillaume II qui pensaient ainsi déstabiliser la Grande-Bretagne en attaquant sur sa frontière occidentale, le Golfe et ses territoires adjacents, le joyau de l’Empire britannique : les Indes. L’Allemagne cristallisa les peurs et anxiétés coloniales des Britanniques quand plusieurs "tribus" du Golfe et de Perse répondirent à l’appel au jihad lancé par le Sultan ottoman à l’automne 1914 et se mobilisèrent contre la Grande-Bretagne. Surtout, Berlin instrumentalisa, d’une part, les rêves de liberté des Bakhtiares du Zagros, déçus par la première révolution constitutionnelle perse et désireux de renégocier les accords signés avec l’Anglo-Persian Oil Company et, d’autre part, le mécontentement des Tangestanis. Les "tribus" étaient pour Berlin un outil destiné à créer ce grand Moyen-Orient dominé par l’Allemagne et à prendre le contrôle du pétrole découvert à la veille du premier conflit mondial par William Knox d’Arcy

Mélanges physico-mathématiques, ou recueil de mémoires : contenant la description de plusieurs machines et instrumens nouveaux, de physique, d'économie domestique, etc

par J. B. Bérar

Order and Disorder in the Relaxor Ferroelectric Perovskite PbSc1/2Nb1/2O3 (PSN): Comparison with Simple Perovskites BaTiO3 and PbTiO3

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Application of DAFS Spectroscopy to Study the Variations of Fe local structure in a Fe/Ir(100) Superlattice

Superlattice studies are important to synthesise 3d metals in new crystalline structure which may exhibit exotic magnetic properties. The challenge is to relate these properties to the details of the chemical gradient and the local strain. We report here on the use of Diffraction Anomalous Fine Structure (DAFS) spectroscopy to separate the XAFS-like information about Fe atoms located at different crystallographic sites of an Fe/Ir(100) superlattice. We obtained the Fe nearest neighbor distances at the Ir-Fe interfaces by the use of a new crystallographic-based analysis of the DAFS data

Detective Quantum Efficiency Modulation Tranfer Function and Energy Resolution Comparison Between CdTe and Silicon Sensors Bump-Bonded to XPAD3S

XPAD3S is a single-photon-counting chip developed in collaboration by SOLEIL Synchrotron, the Institut Louis Néel and the Centre de Physique de Particules de Marseille. The circuit, designed in the 0.25 mm IBM technology, contains 9600 square pixels with 130 mm side giving a total size of 1 cm _ 1.5 cm. The main features of each pixel are: single threshold adjustable from 4.5 keV up to 35 keV, 2 ms frame rate, 107 photons s_1 mm_2 maximum local count rate, and a 12-bit internal counter with overflow allowing a full 27-bit dynamic range to be reached. The XPAD3S was hybridized using the flip-chip technology with both a 500 mm silicon sensor and a 700 mm CdTe sensor with Schottky contacts. Imaging performances of both detectors were evaluated using X-rays from 6 keV up to 35 keV. The detective quantum efficiency at zero line-pairs mm_1 for a silicon sensor follows the absorption law whereas for CdTe a strong deficit at low photon energy, produced by an inefficient entrance layer, is measured. The modulation transfer function was evaluated and it was shown that both detectors present an ideal modulation transfer function at 26 keV, limited only by the pixel size. The influence of the Cd and Te K-edges of the CdTe sensor was measured and simulated, establishing that fluorescence photons reduce the contrast transfer at the Nyquist frequency from 60% to 40% which remains acceptable. The energy resolution was evaluated at 6% with silicon using 16 keV X-rays, and 8% with CdTe using 35 keV X-rays. A 7 cm _ 12 cm XPAD3 imager, built with eight silicon modules (seven circuits per module) tiled together, was successfully used for X-ray diffraction experiments. A first result recently obtained with a new 2 cm _ 3 cm CdTe imager is also presented

UMo/Al nuclear fuel quantitative analysis via high energy X-ray diffraction

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XPAD3-S: A fast hybrid pixel readout chip for X-ray synchrotron facilities

At X-ray synchrotron facilities, scattering experiments require detectors with a large sensitive surface, an high count rate capability, a large counter dynamics, a fast readout system and an adjustable energy threshold. XPAD3 is a new pixellized photon detector based on hybrid pixel technology, which provides low noise data readout at high speed. It is designed in 0.25μm IBM technology and contains 9600 pixels (130μm x 130μm) distributed into 80 columns of 120 elements each. Its features have been optimized to fulfill a count rate capability up to 10^6 photons/pixel/s, an high dynamic range over 35keV, a very low noise of 130e-, and a threshold adjustment well below 4keV. Fast data readout below 2ms/frame is expected. To meet these requirements, an innovative architecture has been designed that makes possible the read out the circuit during acquisition while preserving the precise setting of the thresholds all over the pixel array. The XPAD3 circuit can be bumpbonded with Si, CdTe, or GaAs sensors to optimize its detection efficiency at high X-ray energies. XPAD3 detector modules will be tiled together to form the XPIX detector with a 8cm x 12cm sensitive area. We present first results obtained using a single chip prototype of the XPAD3 detector

XPAD3 hybrid pixel detector applications

Using Si sensors, the XPAD3 chip can be used from 4 up to 25 keV. The CdTe detector was designed to improve efficiency at higher energies (60 keV), but it still works at low energy: data were collected at 8 keV. Firstly, small detector prototypes were built and used for scattering experiments at BM02/ESRF and DIFABS/SOLEIL. Comparisons were made by collecting small angle X-ray scattering data using the same settings with the XPAD3 and the beam line CCD camera, as well as diffuse scattering from a quasi-crystal. Finally, a surface diffraction experiment was performed to characterize the strain in a few layers of GaInAs epitaxially grown on a GaAs single crystal

Application of hybrid pixel detector to powder diffraction.

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