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Acoustic dispersion in silica aerogels observed by brillouin scattering : Evidence for phonon-fracton crossover
- Source :
- Journal of Non-Crystalline Solids. :1175-1180
- Publication Year :
- 1987
- Publisher :
- Elsevier BV, 1987.
-
Abstract
- Small angle neutron scattering and Brillouin scattering experiments have been performed in porous silica aerogels with densities ranging from 0.1 to 0.4 gcm−3. The results demonstrate the fractal structure of these materials. The fractal dimension is D = 2.40 ± 0.02. The high dispersion observed was interpreted in terms of phonon to fracton crossover. From the scaling exponents, we deduced the spectral dimension d = 1.25 ± 0.12. The numerical value of these exponents raises the interesting question of whichis the proper elasticity theory to be applied to these weakly connected structures.
Details
- ISSN :
- 00223093
- Database :
- OpenAIRE
- Journal :
- Journal of Non-Crystalline Solids
- Accession number :
- edsair.doi...........53af023facc7630790ee4594e7ef07e8
- Full Text :
- https://doi.org/10.1016/s0022-3093(87)80731-7