The culprit was continued weakness in ultracapacitor revenue, which down slightly from Q2 2011 because of weakness in Europe.

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Revenue growth has been driven in recent quarters by ultracapacitor sales for hybrid buses and wind turbines, mostly in China.

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In an ultracapacitor, positively charged ions gather on the surface of the negatively charged electrode and negative ions on the surface of the positive electrode.

ECONOMIST: Electricity storage

We also checked out a new ultracapacitor that can charge a power drill in 60 seconds, and researchers are working on energy-generating fabrics that can transform your t-shirt into a power plant.

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In place of a rechargeable battery, it may use an ultracapacitor a more expensive component that stores electrical energy in the same way as a battery, but can retain it almost indefinitely and is not worn out by repeated charging and discharging.

ECONOMIST: Clockwork technology