We present the ElasTool package, an automated toolkit for calculating second-order elastic constants (SOECs) of any two- (2D) and three-dimensional (3D) crystal systems. uses three kinds strain-matrix sets, i.e., high-efficiency sets (OHESS), universal linear-independent coupling strains (ULICS), all-single-element (ASESS), to calculate SOECs automatically. can efficiently compute both zero- hi...

The structures and symmetries of single-walled carbon nanotubes (SWNTs) are introduced in detail. The physical properties of SWNTs induced by their symmetries can be described by tensors in mathematical point of view. It is found that there are 2, 4, and 5 different parameters in the second, third, and fourth rank tensors representing electronic conductivity (or static polarizability), the seco...

We study in detail the influence of molecular interactions on the Frank elastic constants of uniaxial nematic liquid crystals composed of molecules of cylindrical symmetry. A brief summary of the status of theoretical development for the elastic constants of nematics is presented. Considering a pair potential having both repulsive and attractive parts numerical calculations are reported for thr...

The calibration constants that link the peak-shift measured with X-rays to the macroscopic stress acting on the material are termed X-ray elastic constants. These terms contain both material parameters such as the elastic stiffness or compliance terms and configurational parameters caused by the Miller indices of the diffracting plane of the corresponding crystal structure. The configurational ...

The splay and bend elastic constants of the bent-core oxadiazole material [C5-Ph-ODBP-Ph-OC12] have been investigated as a function of temperature across the nematic phase. The bend constant K(33) is found to take values of ~3.0 pN and to be almost temperature independent, whereas, the splay constant K(11) increases monotonically from ~3.5 pN close to the isotropic phase transition to values of...