Optical Society of America

Conquering LED efficiency droop

WASHINGTON, April 30--Like a coffee enthusiast who struggles to get a buzz from that third cup of morning joe, light-emitting diodes (LEDs) seem to reach a point where more electricity no longer imparts the same kick and ...

dateApr 30, 2012 in Engineering
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Redefining time

Atomic clocks based on the oscillations of a cesium atom keep amazingly steady time and also define the precise length of a second. But cesium clocks are no longer the most accurate. That title has been transferred to an ...

dateApr 30, 2012 in General Physics
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