The PLA Navy operates five Type 091 (NATO codename: Han class) nuclear-powered attack submarines built by Huludao Shipyard in Liaoning Province between 1967 and 1990.

So say Raj Mohanty of Boston University and his colleagues, who have created a nanoscale mechanical logic gate that could form the basis of tiny mechanical computers.

I was swinging on the front gate, trying to decide whether to walk down the street to play with Verna, my best friend in fifth grade, when I saw a tramp come up the road.