Millau viaduct geotechnical studies and foundations

AbstractThe Millau viaduct over the Tarn River is an exceptional bridge considering the height under the deck and the 2.5km total length. Each of the seven high piers is founded on a thick raft setting on four large piles of 5m in diameter and 10–15m deep. The ground schematically consists of limestone in the north and of marls in the south. As the bridge is very sensitive to foundation settlements, the concessionary company decided to use the observational method for controlling the displacements and if necessary stabilize the foundations. The measurements show that the movements have remained small and admissible, particularly in terms of the rotations. The settlements have not occurred continuously under the load, but by steps

Current mode monolithic active pixel sensor with correlated double sampling for charged particle detection

A monolithic active pixel sensor operating in current mode for charged particle detection is described. The sensing element in each pixel is an n-well/p-sub diode with a PMOS transistor integrated in an n-well. The drop of the n-well potential from the collection of charge modulates the transistor channel current. Each pixel features two current mode memory cells. The subtraction of distant-in-time samples frees the signal of fixed pattern noise (FPN) and of the correlated low-frequency temporal noise components, resulting in extraction of the particle footprint. The subtraction circuits are placed at each column end. A transimpedance amplifier, integrating in sequence two current samples and subtracting the results in an arithmetic operation, was adopted. The integrated version of the transimpedance amplifier, designed with a maximized conversion gain, is burdened by a risk of an early saturation, imperiling its operation, if the dispersions of the dc current component are too big. The degree of dispersions could not be estimated during the design. Some number of columns is available as a backup with the direct current readout. An external realization of the subtracting circuit, based on the same principle, is used to process direct output columns. The concept of the data acquisition setup developed, the tested performance of an array of cells, and the processing circuitry are described

Floral vascular patterns of the double-flowered and wild-type morphs of Nigella damascena L. (Ranunculaceae)

The perianth of the double-flowered morph of Nigella damascena L. consists of spirally inserted petaloid sepals and sepal-like organs, similar in shape and colour to the petaloid sepals of the wild-type flower. It is devoid of petals. We compare the vascularization of each organ category of the double flower with that of the wild-type. We show that the vascular patterns of the sepal-like organs and of the petals are identical, and found an inverse relationship between the number of bracts and the number of sepals in the double-flowered morph. These two surprising findings will influence the future evo-devo studies on this plant model

P18-01. Exquisite specificity of CTL response to the M184V mutation

International audiencen.

Specific duplication and dorsoventrally asymmetric expression patterns of Cycloidea-like genes in zygomorphic species of Ranunculaceae.

Floral bilateral symmetry (zygomorphy) has evolved several times independently in angiosperms from radially symmetrical (actinomorphic) ancestral states. Homologs of the Antirrhinum majus Cycloidea gene (Cyc) have been shown to control floral symmetry in diverse groups in core eudicots. In the basal eudicot family Ranunculaceae, there is a single evolutionary transition from actinomorphy to zygomorphy in the stem lineage of the tribe Delphinieae. We characterized Cyc homologs in 18 genera of Ranunculaceae, including the four genera of Delphinieae, in a sampling that represents the floral morphological diversity of this tribe, and reconstructed the evolutionary history of this gene family in Ranunculaceae. Within each of the two RanaCyL (Ranunculaceae Cycloidea-like) lineages previously identified, an additional duplication possibly predating the emergence of the Delphinieae was found, resulting in up to four gene copies in zygomorphic species. Expression analyses indicate that the RanaCyL paralogs are expressed early in floral buds and that the duration of their expression varies between species and paralog class. At most one RanaCyL paralog was expressed during the late stages of floral development in the actinomorphic species studied whereas all paralogs from the zygomorphic species were expressed, composing a species-specific identity code for perianth organs. The contrasted asymmetric patterns of expression observed in the two zygomorphic species is discussed in relation to their distinct perianth architecture

Pulsed laser deposited KNbO3_3 thin films for applications in high frequency range

Potassium niobate thin films were grown by pulsed laser deposition on various substrates. Influence of deposition conditions on film characteristics was studied. Structural investigation evidenced that single phase polycrystalline randomly oriented films were grown on sintered alumina whereas epitaxial films were grown on (100)SrTiO$_3$ and (100)MgO substrates. The microstructure was highly controlled by the structural characteristics. Interdigited capacitors built from KNbO3 films on two different substrates (alumina and MgO) showed the strong influence of the structural characteristics on the dielectric behavior. The variation of the equivalent capacitance measured on the interdigital capacitor on MgO was 6.4% at 2.5 GHz while it was 1.5% on alumina, in both cases for a moderate applied field of $\sim$15 kV cm$^{-1}$. The results show the potentiality of these ferroelectric materials for use in frequency agile microwave electronics

Epitaxial growth and properties of lead-free ferroelectric Na0.5Bi0.5TiO3 thin films grown by pulsed laser deposition on various single crystal substrates

International audienceThe epitaxial growth of lead-free ferroelectric Na0.5Bi0.5TiO3 (NBT) thin films on various single crystal substrates was successfully achieved, using the pulsed laser deposition technique (PLD). The present work is divided in two parts, focused on: (i) the growth of NBT layers on c- and r-sapphire (Al2O3) substrates, with and without introducing a CeO2 buffer layer, and (ii) the growth of NBT layers on bare (001)SrTiO3 substrates, with and without introducing a LaNiO3 layer, that could be used as a bottom electrode. In the first part, it was shown that the introduction of a CeO2 buffer layer completely modifies the out-of-plane growth orientation of the NBT films, as well as their microstructure. Indeed, (001)NBT films epitaxially grow only on r-Al2O3 substrates buffered with epitaxial (001)CeO2 layers, while, growing simply NBT on top of bare c or r-Al2O3 substrates, or on top of CeO2/c-Al2O3 heterostructures leads to polycrystalline or textured films. In the second part, we demonstrate that (001)-oriented NBT layers deposited on either bare (001)SrTiO3 or (001)SrTiO3 substrates (STO) covered with (001)LaNiO3 (LNO) are systematically epitaxially grown. Furthermore, the microstructure of the samples is strongly affected by the introduction of the LaNiO3 layer

Multi-time-over-threshold technique for photomultiplier signal processing: Description and characterization of the SCOTT ASIC

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