Mechanical, electronic, and optical properties of Bi₂S₃ and Bi₂Se₃ compounds: first principle investigations.

The structural, mechanical, electronic, and optical properties of orthorhombic Bi₂S₃ and Bi₂Se₃ compounds have been investigated by means of first principles calculations. The calculated lattice parameters and internal coordinates are in very good agreement with the experimental findings. The elastic constants are obtained, then the secondary results such as bulk modulus, shear modulus, Young's modulus, Poisson's ratio, anisotropy factor, and Debye temperature of polycrystalline aggregates are derived, and the relevant mechanical properties are also discussed.

Influence of layer thickness on stress distribution in ceramic-cement-dentin multilayer systems.

The effects of dentin and cement thicknesses on stress level and distribution of crack propagation in ceramic-cement-dentin multilayer complex were analyzed. Custom-designed finite element analysis program based on JL Analyzer was used to analyze the stress distribution and present the maximum principal stress locations. In Zirconia, all the maximum stress values were above 100 MPa.