Poly(vinyl trimethylsilane) and block copolymers of vinyltrimethylsilane with isoprene: anionic polymerization,morphology and gas transport properties.

A new methodology is proposed to estimate 3D displacement fields from pairs of images obtained from X-Ray Computed Micro Tomography (XCMT). Contrary to local approaches, a global approach is followed herein that evaluates {\em continuous} displacement fields. Although any displacement basis could be considered, the procedure is specialized to finite element shape functions. The method is illustrated with the analysis of a compression test on a polypropylene solid foam (independently studied in a companion paper). A good stability of the measured displacement field is obtained for cubic element sizes ranging from 16 voxels to 6 voxels.Comment: nombre de pages = 3

Search for rare and forbidden decays of the charmed meson D+

We report on the results of a search for fourteen flavor changing neutral current, lepton number violating, or lepton family number violating decays of the charmed meson D+ in the large charm sample recorded by the Fetmilab photoproduction experiment E687. No evidence is seen for these rare and standard-model-forbidden decays, of the form D+ -> h(+-) l(-+) l+ (with h = pi, K and l = e, mu); we determine 90% confidence level upper limits on their absolute branching fractions in the range (9-20) x 10(-5)