I.K. Pour, D.J. Krajnovich, et al.
SPIE Optical Materials for High Average Power Lasers 1992
The density of vibrational states in a fractal silica aerogel of Hausdorff dimension D≃2.4 has been determined using spin-echo neutron spectroscopy. A smooth phonon-fracton crossover is found with a fracton spectral dimension of {Mathematical expression}. This direct measurement of {Mathematical expression} near crossover agrees with a previous finding based on scaling Brillouin-spectroscopy results obtained with several samples. We also show that protons adsorbed in the gel vibrate with substantially higher amplitude than the silica matrix. © 1990 Springer-Verlag.
I.K. Pour, D.J. Krajnovich, et al.
SPIE Optical Materials for High Average Power Lasers 1992
Sang-Min Park, Mark P. Stoykovich, et al.
Advanced Materials
J.R. Thompson, Yang Ren Sun, et al.
Physica A: Statistical Mechanics and its Applications
Shiyi Chen, Daniel Martínez, et al.
Physics of Fluids