A Laser-Based Apparatus for Estimating the Hydrogen Diffusion Constant in Gas Mixtures

Abstract

A laser-based apparatus for determining the hydrogen diffusion constant in gas mixtures is described. The main units of the apparatus are a diffusion chamber and a computer-based laser system for the selective diagnostics of hydrogen in gas mixtures by coherent anti-Stokes Raman scattering (CARS) in combination with biharmonic pumping based on stimulated Raman scattering. The diffusion constant is estimated by approximating the experimental data that describe changes in the hydrogen concentration with time at a fixed point in the diffusion chamber and comparing them to the exact solution to the diffusion equation for the chosen one-dimensional experimental geometry.

Photon-Drag Effect in Single-Walled Carbon Nanotube Films

“…To study the photoelectrical properties of the SWCNT films we utilized YAG:Nd 3+ -laser 32 with passive Q-switching, which generates pulses of 20 ns in a single-frequency regime and shorter pulses with 1 ns duration resulting in the multimode partial-locking. To examine the amplitude and polarization characteristics of the photoelectric response single-mode lasing was averaged over 30 flashes.…”