In this work we use density functional theory based on the ultra-soft pseudo-potential to calculate thestructural, mechanical and thermal properties of narrow single walled BN, AlN and GaN nanotubes.The electron-electron interactions were expressed within the local density approximation (LDA). Wehave also obtained the Phonon dispersion and elastic constants of these nanotubes using the densityfunctional perturbation theory. Furthermore the values of Young's modulus, radial breathing modefrequencies and phononic band gaps for BN, AlN and GaN nanotubes (4,0) are reported. Finally it isdemonstrated that the behavior of heat capacity of these nanotubes strongly depends on the mass ofcations. پرونده مقاله