[en] Titanium dioxide (TiO_2) nanotube arrays are attracting increasing attention for use in solar cells, lithium-ion batteries, and biomedical implants. To take full advantage of their unique physical properties, such arrays need to maintain adequate mechanical integrity in applications. However, the mechanical performance of TiO_2 nanotube arrays is not well understood. In this work, we investigate the deformation and failure of TiO_2 nanotube arrays using the nanoindentation technique. We found that the load–displacement response of the arrays strongly depends on the indentation depth and indenter shape. Substrate-independent elastic modulus and hardness can be obtained when the indentation depth is less than 2.5% of the array height. The deformation mechanisms of TiO_2 nanotube arrays by Berkovich and conical indenters are closely associated with the densification of TiO_2 nanotubes under compression. A theoretical model for deformation of the arrays under a large-radius conical indenter is also proposed

[en] Spectroscopic characteristics, efficient and broadly tunable continuous wave (CW) laser operation of a Tm:CLNGG disordered crystal have been investigated for the first time. The disordered crystal laser emits a maximum power of 1.17 W with a slope efficiency as high as 42%. Broadly tunable CW laser operation is achieved in the Tm:CLNGG laser by diode pumping. A wide tuning range from 1896 to 2069 nm has been obtained, suggesting the potential of the disordered crystal for femtosecond pulse generation by mode-locking. (letter)