Porous anodic alumina (PAA) membranes with highly ordered hexagonal cells and a novel pore structure have been fabricated by two-step hard anodization in a H(2)SO(4)-Al(2)(SO(4))(3)-H(2)O system at 40 and 50 V, giving average cell diameters of 77 and 96 nm, respectively. There are several tiny pores embedded in each big shallow pore on the top of the membranes, and there is only one pore in one cell at their bottom. The cells on both sides of the membranes present almost the same periodic arrangement. In order to explore the formation of the novel pore structure, PAA membranes fabricated at different current densities (30-200 mA cm(-2)) are obtained by maintaining a constant voltage at 40 V. The experimental results show that the interpore distance is not only dependent on the anodization voltage, but is also influenced by the current density, which means that the pore structure of PAA membranes fabricated by hard anodization can be accurately designed and controlled by adjusting the anodization voltage and current density simultaneously.

We propose a light-emitting diode headlamp for motorcycles based on freeform micro-lenses. The freeform micro-lenses include a collimator and micro-lens structures. The rays emitted by the light-emitting diode source are first collimated and then redistributed by the microstructures. We make a point by point relationship between the light-emitting diode source and the target plane according to Economic Commission for Europe Regulation R113 revision 2. Simulation results show that the light pattern of our proposed headlamp could satisfy the requirements of the regulation. Illuminance on the test points, lines, and zones can fully meet the Economic Commission for Europe Regulation. The optical efficiency of our proposed headlamp could reach up to 90%, which is much higher than the traditional design.

The illumination quality of a motorcycle lighting system is essential for safety and driving comfort. In this paper, we propose a light-emitting diode (LED) motorcycle low-beam headlamp based on a freeform reflector. The reflector is generated by a freeform optics design method. Then, the optical system is simulated by the Monte Carlo method using commercial optical tracing software. The low-beam headlamp is then fabricated and assembled into a physical object. Both the simulation and measurement results show that the headlamp fully complies with United Nations Economic Commission for Europe (ECE) vehicle regulations.