Marin Soljacic, an assistant professor in MIT's Department of Physics and Research Laboratory of Electronics had a thought. Quite often we forget to recharge our cell phone, and when it is about to die it emits an unpleasant noise. "Needless to say, this always happens in the middle of the night," he said. "So, one night, at 3 a.m., it occurred to me: Wouldn't it be great if this thing charged itself?" He began to wonder if any of the physics principles he knew of could result in new ways of transmitting energy.Labels: energy, technology, wireless