Peng Liyuan, wife of Chinese President Xi Jinping(R), speaks with Melinda Gates, as she walks towards a lab for a tour at the Fred Hutchinson Cancer Research Center in Seattle, Washington, Sept 23, 2015. Bill Gates (L), Co-Chair and Trustee of the Bill and Melinda Gates Foundation and Research Center president and director Dr Gary Gilliland (C), follow in a group behind. [Photo/Agencies]

Separate activities in education and charity

Usually, the couple divides their work during a visit, Chen said. The first lady often takes part in events related to children, education and charity to promote development in the fields and build a friendly national image for China.

On Wednesday, Peng focused her attention on the global-health problems of HIV infection and tobacco use during a tour to the Fred Hutchinson Cancer Research Center in Seattle.

Last September, Peng visited Tagore International School in New Delhi. She also met children with AIDS during a visit to the Republic of Congo in 2013. She was accompanied by the first lady of the country visited at such events.

Peng also tries to promote China-made products during visits. In 2013, at the Women's Development Foundation in Tanzania, she presented China-made skin care products to the hosts, causing a buying craze for the brand among local customers.

"Women often have a gentler image", said Lu. "They play an important role in livening up the otherwise serious atmosphere during state visits".