RESUMO
Fatigue properties and cracking behavior of cold-drawn commercially pure aluminum wires (CPAWs) widely used as the overhead transmission conductors were investigated. It was found that the fracture surface of the CPAWs shows an obvious four-stage fracture characteristic, i.e., crack initiation, planar crack propagation, 45°-inclined crack propagation and final rapid fracture. The crack growth mechanisms for the CPAWs were found quite different from those for the conventional coarse-grained materials. The cracks in the CPAWs firstly grow along the grain boundaries (Stage I crack growth), and then grow along the plane of maximum shear stress during the last stage of cycling (Stage II crack growth), leading to the distinctive fracture surfaces, i.e., the granular surface in the planar crack propagation region and the coarse fatigue striations in the 45°-inclined crack propagation region. The grain boundary migration was observed in the fatigued CPAWs. The increase in fatigue load enhances the dislocation recovery, increases the grain boundary migration rate, and thus promotes the occurrence of softening and damage localization up to the final failure.
RESUMO
Molecular imprinting technique (MIT) involves the synthesis of polymer in the presence of a template to produce complementary binding sites in terms of its size, shape and functional group orientation. Such kind of polymer possesses specific recognition ability towards its template molecule. Despite the rapid development of MIT over the years, the majority of the template molecules that have been studied are small molecules, while molecular imprinting of proteins remains a significant yet challenging task due to their large size, structural flexibility and complex conformation. This review, we summarized the research findings over the past years, and discussed the nano-reinforcing materials used to prepare molecular imprinting of proteins and the perspective of these nano-reinforcing materials.
