摘要：AbstractArbitrary power law attenuation and dispersion in medical ultrasound and elastography can be modeled with temporal memory operators in the wave equation. Here four alternative interpretations are given. Power laws for attenuation with exponents other than 2 correspond to the use of convolution operators expressible as fractional derivatives. The corresponding constitutive equation can be verified by time domain measurements. A framework with multiple relaxation processes can be formulated via the complex compressibility. The constitutive equation can also be expressed with higher order derivatives.
