... electronic structures of BNNTs. Fig-ure 7a,b,c,d,e shows the PDOS of s and p orbitals of B68 and N35 atoms as well as the summation of theseorbitals for the (8,0) BNNT. At strain of 0, there is nocontribution ... armchair BNNTs. Although thestress-strain profiles indicate the mechanical properties of these two BNNTs are very similar, the variations of electronic properties at different uni-axial strains ... elongation of (8,0)BNNT is mainly due to the altering of bond angles andthe elongation of Bond-II, which is parallel to the axialdirection.The relationship of bond lengths and bending angles of (5,5)...