This study paves the way for investigating complex contact-based dynamics of microgranular media, demonstrates a novel acoustic metamaterial, and yields a new approach to studying micro- to nanoscale contact mechanics in multiparticle networks..
Source: wiktionary
Planar metamaterials with subwavelength thickness, or metasurfaces, consisting of single-layer or few-layer stacks of planar structures, can be readily fabricated using lithography and nanoprinting methods, and the ultrathin thickness in the wave propagation direction can greatly suppress the undesirable losses.
Source: wiktionary