An acoustic cloak with concentric alternating layered structure is designed with homogeneous isotropic materials on the basis of effective medium theory. The cloak possesses low-reflection and power-flow bending properties for different shapes of wavefront both in far- and near-fields, which could perfectly approximate the ideal cloak with inhomogeneous and anisotropic distribution of material parameters.

We present theoretically a type of one-dimensional ͑1D͒ structured ultrasonic metamaterial that exhibits a forbidden band where both the effective dynamic density and bulk modulus are simultaneously negative. The material consists of a 1D array of repeated unit cells with shunted Helmholtz resonators. The transmission coefficient, wave vector, negative dynamic density, and modulus are determined by means of the acoustic transmission line method ͑ATLM͒. The double negativity in the effective dynamic density and bulk modulus is an acoustic counterpart of negative permittivity and permeability in the electromagnetic metamaterials. The double negative band is ascribed to the local resonance. In order to confirm the ATLM results, we further calculate the field intensity, phase distribution, and transmission coefficient using the finite element method. In addition, the influences of some essential geometric acoustic parameters on the transmission properties, such as periodic constant L, are also discussed.

Preoperative localization of small peripheral pulmonary nodules using CT-guided embolization coil insertion and subsequent fluoroscopically-guided VATS resection is safer and more effective than conventional VATS.

Bulk conical and surface helical acoustic waves in transversely isotropic cylinders; application to the stiffness tensor measurement