Four-wave sum mixing in beryllium around hydrogen Lyman-α
Radiation was generated between 1210 and 1230 A by four-wave sum mixing in beryllium vapor where the 2s2 1S–2s3d1D transition was two-photon resonant. Results indicate that beryllium will be an efficient nonlinear medium in this spectral region with improvements to the stability of the furnace to allow phase matching and operation at higher pressures.
The main objective of this article is to study dynamic of the ::: three-dimensional Boussinesq equations with the periodic boundary ::: condition.We prove that when the Rayleigh number $R$ crosses the ::: first critical Rayleigh number $R_c$, the Rayleigh-Benard problem ::: bifurcates from the basic state to an global attractor $\Sigma$, which is homeomorphic to $S^3$.