Search

Amorphous TiO2 films were deposited on non-alkali glass by reactive radio-frequency magnetron sputtering using a TiO2 ceramic target. This study analyzed the effects of Ar/O2/N2 gas flow ratios, deposition time, and thermal annealing treatments on the morphological and structural phases and photocatalytic characteristics of the TiO2 films. The XRD results showed a broad hump shape, indicating the existence of an amorphous phase characteristic of TiO2 films. For O2/N2 co-doped TiO2 films, as the O2 and N2 concentration increased, higher photocatalytic activity of TiO2 materials was obtained, while the film growth rate and band gap energy (Eg) values tended to decrease. When increasing the TiO2 film thickness, the amorphous phases remained unchanged, the Eg value narrowed, and higher photocatalytic activity was obtained. After thermal annealing treatments, the TiO2 films showed ultra-hydrophilicity and outstanding photocatalytic efficiency. The TiO2 film annealed at 450°C displayed higher photocatalytic performance and improved mechanical properties. It was seen that when using a higher nanoindentation load, higher hardness (H) and elastic modulus (E) were obtained, but the H/E, H3/E2, and elastic recovery rate (%Re) did not change significantly. [ABSTRACT FROM AUTHOR]

Background: Robot-based joint-testing systems (RJTS) can be used to perform unconstrained laxity tests, measuring the stiffness of a degree of freedom (DOF) of the joint at a fixed flexion angle while allowing the other DOFs unconstrained movement. Previous studies using the force-position hybrid (FPH) control method proposed by Fujie et al. (J Biomech Eng 115(3):211-7, 1993) focused on anterior/posterior tests. Its convergence and applicability on other clinically relevant DOFs such as valgus/varus have not been demonstrated. The current s1tudy aimed to develop a 6-DOF RJTS using an industrial robot, to propose two new force-position hybrid control methods, and to evaluate the performance of the methods and FPH in controlling the RJTS for anterior/posterior and valgus/varus laxity tests of the knee joint.Methods: An RJTS was developed using an industrial 6-DOF robot with a 6-component load-cell attached at the effector. The performances of FPH and two new control methods, namely force-position alternate control (FPA) and force-position hybrid control with force-moment control (FPHFM), for unconstrained anterior/posterior and valgus/varus laxity tests were evaluated and compared with traditional constrained tests (CT) in terms of the number of control iterations, total time and the constraining forces and moments.Results: As opposed to CT, the other three control methods successfully reduced the constraining forces and moments for both anterior/posterior and valgus/varus tests, FPHFM being the best followed in order by FPA and FPH. FPHFM had root-mean-squared constraining forces and moments of less than 2.2 N and 0.09 Nm, respectively at 0° flexion, and 2.3 N and 0.14 Nm at 30° flexion. The corresponding values for FPH were 8.5 N and 0.33 Nm, and 11.5 N and 0.45 Nm, respectively. Given the same control parameters including the compliance matrix, FPHFM and FPA reduced the constraining loads of FPH at the expense of additional control iterations, and thus increased total time, FPA taking about 10 % longer than FPHFM.Conclusions: The FPHFM would be the best choice among the methods considered when longer total time is acceptable in the intended clinical applications. The current results will be useful for selecting a force-position hybrid control method for unconstrained laxity tests using an RJTS. [ABSTRACT FROM AUTHOR]