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BACKGROUND: Previous studies have shown that titanium nanotubes with different diameters effect the adhesion and growth of cells on the implant surface. OBJECTIVE: To investigate the effects of annealing treatment on the biological behaviors of fibroblasts on the surface of TiO2 nanotubes with different diameters. METHODS: TiO2 nanotubes were prepared by polishing pure titanium samples through anodizing at 5 V and 20 V respectively, and then annealed. The pure titanium samples were divided into six groups: P (polishing titanium), NT5 (TiO2, nanotubes prepared at 5 V), NT20 (TIO2 nanotubes prepared at 20 V), A-P (annealing treatment and polishing titanium), A-NT5 (TiO2, nanotubes prepared at 5V and annealed) and A-NT20(TiO2, nanotubes formed at 20 V and annealed). Field emission scanning electron microscopy was used to obsesrve the surface topography. Fibroblasts were inoculated on the surface of each group of samples. After 60 and 120 minutes of culture, the number of cells adhering to titanium sample surface was counted using cell nucleus staining method. On day 1 of culture, cell morphology was observed using scanning electron microscopy. On days 1, 3 and 5 of culture, cell proliferation was detected by MIT method. On day 3 of culture, the secreation of collagen fiber was detected by picro-sirius red staining method. RESULTS AND CONCLUSION: (1) The annealing treatment had no significant effect on the morphology and diameter of the nanotubes. (2) The number of adherent cells in the NT5 and NT20 groups was significantly lower than that in the P group. The annealing treatment the number of fibroblasts on the surface of polished pure titanium and decreased the number of fibroblosts in the NT5 and NT20 groups. (3) Annealing enhanced the viability of fibroblasts on the surface of polished pure titanium and decreased the viability of cells on the surface of nanotubes prepared at 5 and 20 V. (4) Cell viability in the NT5 and NT20 groups was lower than that in the P group. Annealing treatment increased the viability of cells on the surface of polished pure titanium and decreased the viability of cells on the surface of nanotubes prepared at 5 and 20 V. (5) The level of collagen on the surface of nanotubes in the NT5 and NT20 groups was higher than that in the P group. Annealing treatment increased the level of collagen on the surface of polished pure titanium and decreased the level of collagen in the NT5 and NT20 groups. These findings suggest that TiO2, nanotubes inhibit the adhesion, spreading and proliferation of fibroblasts to different degrees; annealing treatment can enhance this inhibitory effect; TiO2, nanotubes enhance collagen secreation by fibroblasts to different degrees, and annealing treatment inhibits the enhancement. [ABSTRACT FROM AUTHOR]

The work aims to study tribology performance of dialkyl dithiocarbamic borate ester. A new extreme pressure and anti-wear additive of dialkyl dithiocarbamic borate ester(CNSB) was synthesized. When dialkyl dithiocarbamic borate ester was added to the base oil in proper proportions, the result was lubricating oil. Tribology performance of various lubricating oil was investigated by using a four-ball tester. Surface topography of wear scar was observed through scanning electron microscopy. By observing wear scar diameter, friction coefficient, maximum nonseizure load and surface topography of wear scar, the tribology performance and friction mechanism was investigated. With the increase of quality fraction of additive CNSB, friction coefficient, wear scar diameter and friction coefficient decreased rapidly, but the maximum nonseizure load increased significantly. The wear scar diameter of oil samples with 1.5% addition amount of CNSB decreased by 28.95%. The friction coefficient of oil samples with 2.0% addition amount of CNSB decreased by 34.48%. The maximum nonseizure load of oil samples with 2.0% addition amount of CNSB increased by 539 N. In the course of friction, the synthetic CNSB was decomposed. The appeared active S elements and a small number of N and B elements formed lubrication protective film, resulting in lower friction coefficient and good wear resistance. [ABSTRACT FROM AUTHOR]

High-strength carbon fiber reinforced polymer (CFRP) with unidirectional laminate structure has gradually developed into major materials in load-bearing aerospace components, and relevant demand in cutting and machining is increasing. Owing to significant anisotropy, CFRP materials with unidirectional laminate structure incline to produce defects and are typical difficult-to-machine materials. By orthogonal cutting experiments, cutting force, specific energy, cutting temperature and machined surface are obtained when cutting T700 high-strength CFRP unidirectional laminates under different fiber orientations. Based on experimental results, mechanical and thermal anisotropy of CFRP uniform laminates are discussed, specific energy maps under different cutting parameters are achieved, heat sources are studied, and the conduction model is established. By scanning electron microscope (SEM) topography of typical surfaces, surface formation mechanism under different fiber orientations is given. [ABSTRACT FROM AUTHOR]

In order to analysis whether the wool/polyester fabrics' aurora phenomenon relate to its surface microstructure and composition. This paper studied the wool/polyester surface microstructure by means of scanning electron microscopy (SEM), and also analyzed the surface material composition through the VERTEX 70 FT-IR spectrometer, CHNS/O Organic element analyzer and Gas chromatography mass spectrometry (GC-MS). We reached that the wool/polyester fabrics, wool scale severely damaged under the action of the tension, friction, compression and external mechanical forces in wearing process. The fabrics, surface really exists grease and lipid materials, which is also the important reasons that caused the fabrics aurora phenomenon. [ABSTRACT FROM AUTHOR]