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This paper investigates the removal of material from a surface during polishing with ®xed abrasives. The material removal pro®le prescribes the amount of material removed from the surface along a direction orthogonal to the tool path as a polishing tool is moved along the surface. It depends on the geometry and mechanical properties of the tool and the surface as well as on the polishing condition. A wear index for polishing is introduced to relate the material removal to the polishing condition. On the basis of the wear index, an approach for calculating the material removal pro®le is developed. It assumes that the pressure distribution is Hertzian at the contact between the tool and the surface. Polishing experiments are conducted which consist of polishing convex surfaces with cylindrical tools and concave surfaces with spherical tools. The proposed approach has been con®rmed by measurements of material removal pro®les in these experiments.

Uniform TiO 2 /SiO 2 composite films were prepared on ITO substrates by electrodeposition, and highly photoelectrocatalytic (PEC) activity of the composite films was observed toward the degradation of methyl orange (MO) in aqueous solutions. It was further found that their PEC activity was dependent on the electrodeposition parameters including deposition time, solution pH and SiO 2 content. Under the optimized condition, the PEC degradation of MO on TiO 2 /SiO 2 composite film electrode could be enhanced about 14 times relative to that on neat TiO 2 film electrode. The high PEC activity of the TiO 2 / SiO 2 composite film electrode was mainly attributed to the enhancement of the charge separation of photo-generated electron-hole pairs by the dispersion of SiO 2 nanoparticles in the TiO 2 matrix with the aid of the applied electric field.

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The effects of mineral salts on the formation of titanate nanostructures (nanowires/rods/tubes/sheets) were investigated in alkaline hydrothermal systems. The curving of single-layer titanate nanosheets into sub-microtubes and the self-assembling of titanate nanofibers into nanowires were observed directly. A new concept of tailoring titanate nanostructures was developed by commanding NaCl concentrations, and the revolved hydrothermal treatment was found to require much lower NaOH concentration and reaction temperature. On the basis of both TEM and XRD analysis, a theoretical model for the tailoring process was provided in consideration of the salt's contribution to the growth rate of titanate nanomaterials via controlling the crystallization.