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Triply Periodic Minimal Surface (TPMS) porous structures are recognized as the most promising bionic artificial structures for tissue engineering. The fatigue properties of additive manufactured porous structures are essential for long-term use in a dynamical bio-skeletal environment. The aim of this study is to study the compression–compression fatigue behaviour and the underlying fatigue mechanism of Gyroid cellular structures (GCS), a typical TPMS porous structure. The high-cycle fatigue results show that both cyclic ratcheting and fatigue damage phenomena contribute to the failure of GCS during fatigue testing. For most fatigue loading stress, the failure samples have nearly 45° fracture bands along the diagonal surface. The fatigue ratio of GCS reaches 0.35 for as-built samples and can be raised to 0.45 after sandblasting treatment. The fatigue ratio values are higher than most of the other bending-dominated lattice structures, suggesting superior fatigue resistance properties of GCSs due to the smooth surface connection between struts. Besides, a systematic investigation of the crack initiation and propagation was conducted by both deformation analysis and finite element method to support experimental phenomena. The results also indicate that the fatigue resistance properties of GCSs are significantly enhanced by sandblasting post-treatment, through removing the adhered powder particles, inducing compressive residual stress on the surface and generating a nanocrystalline zone.

According to the composite design, a series of black TiO2/graphene composites were synthesized to improve its photocatalytic activity. TiO2 is generated in situ on the surface of graphene by a facile sol-gel method. The combination of graphene and TiO2 was beneficial for eliminating the opportunity of photogenerated electron-hole recombination due to the excellent conductivity of graphene. In the subsequent hydrogenation process, the self-doping Ti3+ was introduced accompanied by the crystallization of amorphous TiO2. The narrowed bandgap caused by self-doping Ti3+ enhanced the visible light absorption and make the composites appear black. Both of them improved the photocatalytic performance of the synthesized black TiO2/graphene composites. The band structure of the composite was analyzed by valence band XPS, revealing the reason for the high visible light catalytic performance of the composite. The results proved that the black TiO2/graphene composites synthesized show attractive potential for applications in environmental and energy issues.

The Strategy of choosing local region in the facial image of LRPCA makes it perform efficiently in human face recognition. One kernel of LRPCA is the Local Region Choose. So prefer the better performs of LRPCA on human face recognition, the region choose strategy is proposed to be the key. By the discussion of the some region templates, a well strategy is given by experiments.