1,022 research outputs found
Nano-building block based-hybrid organic–inorganic copolymers with self-healing properties
New dynamic materials, that can repair themselves after strong damage, have been designed by hybridization of polymers with structurally well-defined nanobuilding units. The controlled design of cross-linked poly(n-butyl acrylate) (pBuA) has been performed by introducing a very low amount of a specific tin oxo-cluster. Sacrificial domains with non-covalent interactions (i.e. ionic bonds) developed at the hybrid interface play a double role. Such interactions are strong enough to cross-link the polymer, which consequently exhibits rubber-like elasticity behavior and labile enough to enable, after severe mechanical damage, dynamic bond recombination leading to an efficient healing process at room temperature. In agreement with the nature of the reversible links at the hybrid interface, the healing process can speed up considerably with temperature. 1H and 119Sn PFG NMR has been used to evidence the dynamic nature of these peculiar cross-linking nodes
The role of cellular communication in bone marrow derived stromal cell chondrogenic differentiation
Invertébrés marins du lagon néo-calédonien : 1. Etude structurale d'une nouvelle sapogénine extraite d'une Holothurie Bohadschia vitiensis Semper = marine invertebrates from New-Caledonian lagoon : 1. Structural study of a new sapogenin isolated from a sea-cucumber Bohadschia vitiensis Semper
Invertébrés marins du lagon Néo calédonien : 3. Etude structurale de trois nouveaux diterpènes isolés du pennatulaire Cavernulina grandiflora
Three new diterpenes, related to stylatulide but non-balogenated, have been isolated from a new species of sea-pen, Cavernulina grandiflora : cavernuline (1) O-deacetylpropionyl cavernuline (5) and cavernulinine (6). The structures are proposed on the basis of spectral evidence
Measurement and Control of the Beam Energy for the SPIRAL2 Accelerator
WEPF32, http://accelconf.web.cern.ch/AccelConf/ibic2013/International audienceThe first part of the SPIRAL2 facility, which entered last year in the construction phase at GANIL in France, will be composed of an ion source, a deuteron/proton source, a RFQ and a superconducting linear accelerator delivering high intensities, up to 5 mA and 40MeV for the deuteron beams. As part of theMEBT commissioning, the beam energy will be measured on the BTI (Bench of Intermediate Test) at the exit of the RFQ. At the exit of the LINAC, the system has to measure but also control the beam energy. The control consists in ensuring that the beam energy is under a limit by taking account of the measurement uncertainty. The energy is measured by a method of time of flight, the signal is captured by non-intercepting capacitive pick-ups. This paper presents also the results obtained in terms of uncertainties and dynamics of measures
Hodge polynomials of some moduli spaces of Coherent Systems
When , we study the coherent systems that come from a BGN extension in
which the quotient bundle is strictly semistable. In this case we describe a
stratification of the moduli space of coherent systems. We also describe the
strata as complements of determinantal varieties and we prove that these are
irreducible and smooth. These descriptions allow us to compute the Hodge
polynomials of this moduli space in some cases. In particular, we give explicit
computations for the cases in which and is even,
obtaining from them the usual Poincar\'e polynomials.Comment: Formerly entitled: "A stratification of some moduli spaces of
coherent systems on algebraic curves and their Hodge--Poincar\'e
polynomials". The paper has been substantially shorten. Theorem 8.20 has been
revised and corrected. Final version accepted for publication in
International Journal of Mathematics. arXiv admin note: text overlap with
arXiv:math/0407523 by other author
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