Some new mesoscopic crossover length scales concerning the Hamaker constant

The last three decades have witnessed a global surge in nano-and micro-mechanics driven by the rapid development of nanotechnology,microelectromechanical systems(MEMS)and nanoelectromechanical systems(NEMS)[1].Although a generally accepted framework is still lacking for mesoscopic mechanics,four broad categories of viewpoints have been agreed upon[2]:(1)Continuum mechanics works quite well even for a few atoms in diameter.In 1997,Richard E.Smalley(1943-2005),the late Nobel laureate,and Yakobson[3]once commented:“The behavior of the hollow tubules is complex,but still predictable with continuum-elastic methods.In its applications to nanotubes,the correspondence between the elastic model and molecular dynamics is remarkable.The laws of continuum mechanics are amazingly robust and al-low one to treat even intrinsically discrete objects only a few atoms in diameter.”