Acoustic scattering

For completeness, we include in this brief survey a schematic diagram of the photoacoustic method (Fig. I4.2e), which has been discussed in Section 11.7. Absorption of chopped light by the particles gives rise to periodic heating which is detected acoustically. Scattered light does not contribute to the signal. 

Kogan, Sh.M. Piezoelectric effect during inhomogeneous deformation and acoustic scattering of carriers in crystals. Soviet Phys.-Solid State 5, 2069 (1964). 

Sirotyuk (ref. 25) found that the complete removal of solid particles from a sample of water increased the tensile strength by at most 30 percent, indicating that most of the gas nuclei present in high purity water are not associated with solid particles. Bernd (ref. 15,16) observed that gas phases stabilized in crevices are not usually truly stable, but instead tend to dissolve slowly. This instability is due to imperfections in the geometry of the liquid/gas interface, which is almost never exactly flat (ref. 114). Medwin (ref. 31,32) attributed the excess ultrasonic attenuation and backscatter measured in his ocean experiments to free microbubbles rather than to particulate bodies this distinction was based on the fact that marine microbubbles in resonance, but prior to ultrasonic cavitation (ref. 4), have acoustical scattering and absorption cross sections that are several orders of magnitude greater than those of particulate bodies (see Section 1.1.2). 

When the extinction is measured at different frequencies/, this equation becomes a linear equation system, which can be solved for Cpp and q2(x). The key for the calculation of the particle-size distribution is the knowledge of the related extinction cross section K as a function of the dimensionless size parameter c = iTOifk. For spherical particles K can be evaluated directly from the acoustic scattering theory. A more general approach is an empirical method using measurements on reference instruments as input. 

Coussios CC, Holland CK, Jakubowska L, Huang SL, MacDonald RC, Nagaraj A, McPherson DD (2004) In vitro characterization of liposomes and Optison by acoustic scattering at 3.5 MHz. Ultrasound Med Biol 30 181-190... 

V. I. Ryzhii, Microwave photoconductivity in two-dimensional electron systems due to photon assisted interaction of electrons with leaky interface phonons, Phys. Rev. B 68, 193402 (2003) V. Ryzhii et al.. Absolute negative conductivity in two-dimensional electron systems associated with acoustic scattering stimulated by microwave radiation, Phys. Rev. B 68, 165406 (2003). 

The acoustic diffuse scattering is centred at the Bragg positions and can constitute a significant source of errors in integrated intensity measurements. The characteristic fine collimation of SR can be exploited in the collection of data to minimise the acoustic scattering contribu-... 

B. Peterson, S. Strom, Matrix formulation of acoustic scattering from an arbitrary number of scatterers, J. Acoust. Soc. Am. 56, 771 (1974)... 

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