多年来 ,科学家们一直致力于发动机微型化。自蒸汽机在 2 0 0多年前问世以来 ,科学家们绞尽脑汁 ,试图发明体积越来越小的发动机。不久前 ,由美国波士顿大学化学家罗斯·凯利及其同事研制成功的分子发动机 ,称得上是这一领域内取得的重大突破。分子发动机的体积小得不可思议 :? For many years, scientists have been working on miniaturization of engines. Since the steam engine was introduced more than 200 years ago, scientists have racked their brains to try to invent smaller and smaller engines. Not long ago, the successful molecular engine developed by Boston University chemist Rose Kelly and his colleagues was a major breakthrough in this area. The size of the molecular engine is incredible:?