The electrical resistivity of a thermoresponsive polyurethane shape-memory polymer ͑SMP͒ filled with micron sized Ni powders is investigated in this letter. We show that, by forming conductive Ni chains under a weak static magnetic field ͑0.03 T͒, the electrical conductivity of the SMP composite in the chain direction can be improved significantly, which makes it more suitable for Joule heat induced shape recovery. In addition, Ni chains reinforce the SMP significantly but their influence on the glass transition temperature is about the same as that of the randomly distributed Ni powders.

Research in the area of free space optical communications is largely based on fixed point-to-point link or long range link for space applications, employing a single beam divergence for the applications. For short-range interUnmanned Aerial Vehicle (UAV) optical communications, a single beam divergence employed in the link may limit the transmission distance between UAVs. To address this problem, adaptive beam divergence is required. Several methods to implement this in the form of beam divergence changing mechanisms are proposed in this paper. It is shown how adaptive beam divergence will reduce the requirements of other system parameters such as receive aperture diameter, transmit power and pointing ability.

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Butterfly-shaped features (with sizes from about 6 to 90 μm) were found on the surface of a shape-memory polymer (SMP) after a process of 50% stretching, slightly polishing, and then heating for shape recovery. We identified the underline mechanism, which is evidenced by the switching of butterflies by 90° from the previous direction after stretching. The case discussed here demonstrates the feasibility of using SMPs for patterning up to nanoscale for different shapes.