The outlook for new technology

In science-fiction adventures, laser beams bring aircraft crashing out of the sky. At NASA, they keep them aloft. A research team from the space agency has successfully flown a miniature aircraft that gets its power entirely from an invisible ground-based laser (Picture). The laser strikes the plane's underside, where a panel of photovoltaic cells converts the light into electricity to power the craft's propeller.

The remote-controlled test plane, made of balsa wood, carbon-fiber tubing, and Mylar film, has a 5-ft wingspan and weighs only 11 oz. So, we shouldn't expect to see lasers powering piloted aircraft anytime soon. However, the ability to keep even a small craft aloft without forcing it to carry its own fuel or batteries could be a boon to military, telecommunications, and scientific applications. The research team includes members from NASA's Marshall Space Flight Center, its Dryden Flight Research Center, and the University of Alabama.

You may think MEMS (microelectrical mechanical systems) are primarily for sensor and actuator functions, but a properly structured device can perform real-time signal processing. At Draper Laboratory (www.draper.com), researchers have built a MEMS device that uses an array of as many as eight resonator elements to implement an analog-domain, real-time, compressed-Fourier transform for video signals (Picture). As the analog signal passes through the resonators, their intrinsic physical responses provide the necessary amplitude and phase response equivalent to the Fourier coefficients. The output of the MEMS device then passes through a conventional gain stage and A/D converter.

Why even bother to do this task when compression-optimized converters and ICs are available? The MEMS-based approach potentially uses much less power than a high-resolution, high-speed A/D converter followed by a compression IC. The MEMS compressor uses very little power itself, and the subsequent active components are lower resolution and lower power devices than those that the conventional approach uses.
—by Bill Schweber

A Rice University research team claims that building electronic circuits doesn't necessarily require delicate precision. In fact, disordered, self-assembling collections of gold nanowires and organic molecules can function as nonvolatile memory, the team reports. The group has created memory circuits that hold their contents for more than a week at room temperature. Next up, determining whether devices constructed in this way can handle logic functions, too.

A current of a few microamps normally warrants little attention. But a tiny electron flow at the University of Alberta has created a commotion because researchers generated it simply by forcing ordinary tap water through fine pipelines.

Hailed as the first new way to generate electricity in more than 150 years and a possible source of pollution-free, renewable energy, the innovation rests on elementary physics. As water flows over a surface, ions in the water rub up against the surface, creating a charge. By squeezing water through a large number of microchannels in a block of glass, the scientists were able to create sufficient current to illuminate LEDs.

The researchers note that commercial-scale applications would require massive bodies of water but speculate that the technology may be feasible for powering cell phones and other small electronic devices.