53 research outputs found
Les processus physiques à l'embouchure de l'Amazone
La campagne Amazomix est la première campagne multidisciplinaire menée face au plateau amazonien. Elle a été conçue pour répondre aux très nombreuses questions qui se posent sur les processus physiques et biogéochimiques et sur leurs impacts sur l'ensemble de l'écosystème marin du plateau continental situé en face de l'embouchure de l'Amazone
Processos físicos na foz do Amazonas
A campanha Amazomix é a primeira campanha multidisciplinar a ser realizada no planalto amazônico. Ela foi projetada para responder às muitas questões que surgem sobre os processos físicos e biogeoquímicos e seus impactos em todo o ecossistema marinho da plataforma continental diante à foz do Amazona
Intercalation of graphite and hexagonal boron nitride by lithium
Although graphite and hexagonal form of BN (h-BN) are isoelectronic and have very similar lattice structures, it has been very difficult to
intercalate h-BN while there are hundreds of intercalation compounds
of graphite. We have done a comparative first principles investigation of lithium intercalation of graphite and hexagonal boron nitride to provide clues for the difficulty of h-BN intercalation. In
particular lattice structure, cohesive energy, formation enthalpy,
charge transfer and electronic structure of both intercalation
compounds are calculated in the density functional theory framework
with local density approximation to the
exchange-correlation energy. The calculated formation enthalpy
of the considered forms of Li intercalated h-BN is found to be positive which rules out h-BN intercalation without externally supplied energy. Also, the Li(BN)3 form of Li-intercalated
h-BN is found to have a large electronic density of states at the Fermi level and an interlayer state that crosses Fermi level at the zone center; these properties make it an interesting material to investigate the role of interlayer states in the superconductivity of alkali intercalated layered structures. The most pronounced change in the charge distribution of the intercalated compounds is found to be charge transfer from the planar σ states to the π states
Measurements of CP-Violating Asymmetries in the Decay B^{0}→K^{+}K^{-}K^{0}
We analyze the decay B0→K+K-K0 using 383×106 BB̅ events collected by the BABAR detector at SLAC to extract CP violation parameter values over the Dalitz plot. Combining all K+K-K0 events, we find ACP=-0.015±0.077±0.053 and βeff=0.352±0.076±0.026 rad, corresponding to a CP violation significance of 4.8σ. A second solution near π/2-βeff is disfavored with a significance of 4.5σ. We also report ACP and βeff separately for decays to ϕ(1020)K0, f0(980)K0, and K+K-K0 with mK+K->1.1 GeV/c2
Measurement of the time-dependent CP asymmetry in B0→DCP(*)h0 decays
We report a measurement of the time-dependent CP-asymmetry parameters S and C in color-suppressed B-0 -> D((*)0)h(0) decays, where h(0) is a pi(0), eta, or omega meson, and the decays to one of the CP eigenstates K+K-, K-S(0)pi(0), or K-S(0)omega. The data sample consists of 383x10(6) Upsilon(4S)-> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. The results are S=-0.56 +/- 0.23 +/- 0.05 and C=-0.23 +/- 0.16 +/- 0.04, where the first error is statistical and the second is systematic
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