Abstract: A slow light system includes a substrate and a metal layer formed thereon, the metal layer having a graded grating structure formed at a surface thereof, wherein the grating depth of the grating structure is sized such that surface-plasmon polariton dispersion behavior of the grating structure differs at different respective locations along the grating structure. Different wavelengths of incident light waves can be slowed at the respective locations along the grating structure.

Abstract: A process and apparatus for oxidizing methanol in a gas stream into formaldehyde in a fixed bed reactor. The process first introduces a gas stream into a fixed bed reactor. The fixed bed reactor contains a catalyst bed having a depth, a width, a length, an inlet, an upstream region, a downstream region and an outlet. Preferably, the inlet, the upstream region, the downstream region and the outlet are provided in the order stated. A vanadia-titania catalyst is provided in the upstream region and a molybdena-titania catalyst is provided in the downstream region. The vanadia-titania catalyst in the upstream region is substantially free of MoO3 and initially (i.e., during oxidation some V2O5 may sublime and migrate to the downstream region) the molybdena-titania catalyst in the downstream region is substantially free of V2O5. Next, the gas stream is contacted with the vanadia-titania catalyst under oxidizing conditions.