论文和技术资料

When the particles in a colloid come close to each other, multiple scattering in ultrasonic beams is no longer negligible and crowded particle effects emerge. The presence of each particle affects the scattering of all others, leading to coupling effects. We investigate the interaction of a range of sizes of particles, arranged periodically or randomly (in medium to high ultrasonic frequency fields), to understand their coupling and physical properties.

In order to determine the movement of particles in an ultrasonic field an investigation of small numbers of particles is also initially undertaken in order to firstly determine the extent of the displacement (and the function of particle position with respect to the origin of the ultrasonic beam) and secondly to understand coupled particle effects. One silica particle in water demonstrates the displacement in the field. Two particles are then used to show the range of interaction before examining chains and clusters. Other interactive energies, due to Coulomb repulsion are excluded from the analysis to completely focus on the wave motion and determine its influence on the particles (with neutral charge). It is expected that as the concentration of particles increases, the influence of shear-waves effects on an attenuation will become large [1].