Abstract: The three-dimensional (3D) multiporous structure polyimides were obtained by introducing of the triphenylamine (TPA) unit as linkage in the pyromellitic-based polyimide (N1) and the naphthalene-1,4,5,8-tetracarboxylic-based ...

Abstract: Cracking in 25Cr35NiNb pyrolysis furnace tubes is difficult to detect in engineering production. This paper presents a metal magnetic memory technique for inspecting cracks. To verify the effectiveness of the proposed ...