为了验证他们的假设，研究人员使用了一些电灯，实际是使用了发光二极管。
To test their hypothesis, researchers took some electrical lights, actually, they were light-emitting diodes.
基于蓝宝石的氮化镓发光二极管的一般内量子效率约为70%。
A gallium nitride LED on sapphire has a typical internal quantum efficiency of around 70%.
不断变化的建筑规范、人们逐渐发展的品味，以及维护这些精美的旧标志牌的高昂成本，让企业欣然接受了发光二极管。它们节约能源，但成本仍然很高。
Changing building codes, evolving tastes, and the high cost of maintaining those wonderful old signs have businesses embracing LEDs, which are energy efficient but still carry great cost.
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