<< When [AA] placed the material inside a gas chamber and cranked up the air pressure from one bar (about the atmospheric pressure at sea level) to five bars, the cube’s volume increased by about 3 percent >>
Maria Temming. This material does weird things under pressure. Microcube is designed so that pressure makes it expand instead of compress. Science News. 2017; 192 (11): 12. Dec 23, 2017.
Jingyuan Qu, Alexander Gerber, et al. Experiments on Metamaterials with Negative Effective Static Compressibility. Phys. Rev. 2017; X7, 041060. Dec 8, 2017