1,206 research outputs found
Equatorial and tropical weathering of recent basalt from Cameroon : Allophanes, halloysite, metahalloysite, kaolinite, gibbsite
Sur l'origine de la silice des silicifications climatiques et des diatomites quaternaires du Sahara
Nonlinear polarization effects in optical fibers: polarization attraction and modulation instability [Invited]
We review polarization stabilization techniques based on the polarization attraction effect in low-birefringence
fibers. Polarization attraction or pulling may be based on cross-polarization modulation, on parametric amplification,
and on Raman or Brillouin scattering. We also review methods for laser frequency conversion based on
polarization modulation instabilities in low- and high-birefringence fibers, and photonic crystal fibers. Polarization
instabilities in nonlinear fibers may also be exploited for sensing applications
Equatorial and tropical weathering of recent basalts from Cameroon : Allophanes, halloysite, metahalloysite, kaolinite and gibbsite
La distribution des bauxites sur le craton ouest-africain
Les études antérieures menées sur les bauxites latéritiques permettent de distinguer des faciès originels d'altération et des faciès dérivés de dégradation. Dans le paysage, leur étagement correspond à des mécanismes d'aplanissements géochimiques. A l'échelle du craton ouest-africain, les différences d'altitude des gisements rendent compte du bombement du craton au cours du Tertiair
Parabolic pulse generation with active or passive dispersion decreasing optical fibers
We experimentally demonstrate the possibility to generate
parabolic pulses via a single dispersion decreasing optical fiber with normal
dispersion. We numerically and experimentally investigate the influence of
the dispersion profile, and we show that a hybrid configuration combining
dispersion decrease and gain has several benefits on the parabolic generated
pulses
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