Joan Hinton, 88, nuclear physicist and dairy farm owner in Beijing

A US-born scientist who once worked on the Manhattan Project, Joan Hinton now runs a dairy farm in the north of Beijing.

Born in 1921, Hinton has spent more than 60 years in China and is now a Chinese citizen.

In 1945, 23-year-old Hinton was one of the few women to work on developing the first atom bomb.

Even as she rejoiced in the success of the endeavor, she was deeply shocked when the US government dropped the bomb on Hiroshima and Nagasaki in Japan in 1945. She quit the project and arrived in Shanghai in 1948 and then went to Yan'an, where she married her longtime boyfriend Erwin Engst (Yang Zao), who had been working as an advisor to the Chinese government since 1946.

The couple participated vigorously in China's efforts to build a socialist economy, working extensively in agriculture. They designed, built and operated China's first mechanical farm.

Hinton's most prized possession is an old violin, made in Italy in the 19th century, that has been a constant companion for the past 60 years.

When the melodious sounds of Dong Fang Hong (East Is Red) resonates through the farm, her staff know that Hinton is playing her beloved violin.

Her husband died in 2003, and his ashes lie buried on their farm.

All her three children are in the US, but she refuses to leave.

"China has already become my second hometown. Now, my 200 cows are my best friends and my greatest concern. I am already 88 and want to do something for the dairy farm for the rest of my life," she says.