Oscillatory behavior of novel heterogeneous oscillators composed of carbon and molybdenum disulfide nanotubes (CNT@MST) was investigated for the first time, by using the methods of classical molecular dynamics. In the proposed oscillators, a molybdenum disulfide nanotube (MST) was set as an outer tube, leading to better compatibility with the semiconductor industry standards. A smooth and stable oscillator with a frequency reaching 20 GHz was obtained based on a double-walled CNT@MST hetero-nanotube for a wide range of gap widths, indicating that the proposed oscillators perform much better than those built from double-walled carbon nanotubes (CNTs) that require a narrow range of gap widths. In addition, the oscillation characteristics of CNT@MST oscillators containing different inner and outer tube chirality were significantly better than those of CNT@MST oscillators containing two tubes with the same chirality.

The effective material properties of piezoelectric composites are predicted using micromechanics models of the composite structure combined with a boundary element method (BEM) solution of the governing equation. The composites consist of inclusion and matrix phases. The micromechanics method gives formulae for the overall material constants as functions of the concentration matrix, while the boundary element simulation gives numerical solutions of the boundary displacement and electric potential equations for inclusion or hole problems. Numerical results for a piezoelectric plate with circular inclusions are presented to illustrate applications of the proposed micromechanics-BEM formulation.