No abstract

First-principles calculations were conducted on armchair graphene nanoribbons (AGNRs) to simulate the elastic behavior of AGNRs with hydrogen-terminated and bare edges. The results show width-dependent elastic properties with a periodicity of three, which depends on the nature of edge. The edge eigenstress and eigendisplacement models are able to predict the width-dependent nominal Young's modulus and Poisson's ratio, while the Clar structure explains the crucial role of edges in the periodically modulated size-dependent elastic properties.

In this study, the influences of the adsorption of water molecules on the changes in the atomic and electric structures of BaTiO3 surface were investigated using ab initio calculation. Water molecules are molecularly and dissociatively adsorbed on the BaTiO3 surface, which makes electrons transfer from water molecules to the BaTiO3 surface. The redistribution of electrons in the BaTiO3 surface layers weakens the Ba-O interactions and strengthens the Ti-O interactions, so that the Ti atom shifts in TiO2 plane, i.e., an in-plane domain switching. The adsorption of water molecules on BaTiO3 surfaces also results in a reduction in the surface rumpling.

The presence of microorganisms influences corrosion of metallic materials by either an accelerating or an inhibiting effect. While most studies have focused on corrosion influenced by bacteria, especially sulphate-reducing bacteria, fungus (or mould) is another form of microorganisms which can significantly affect corrosion processes. This study investigated the effects of two common fungi, Paecilomyces variotii and Aspergillus niger, on corrosion of 304 stainless steel immersed in aqueous environment for up to 28 days. Biofilm formation was observed by SEM. Instead of accelerating corrosion, electrochemical studies such as potentiodynamic polarisation and electrochemical impedance spectroscopy have shown inhibitive effects of these fungi to corrosion of 304 stainless steel.

No abstract