'Chinese people were proud of their achievements, but they were still uncertain about the future. Outsiders view China as strong and rich, but there is still a lot of poverty inside the country. I wanted to capture the mixture of feelings at that moment.'

The photographs are an intersection point for many contradictory ideas: the girls wear T-shirts emblazoned with English-language statements they don't understand and they are photographed in Tiananmen Square, with its recent dark history.

'My main reference points were the propaganda posters from the Cultural Revolution,' Zhang says. 'Everyone looks happy and the colours are very bright in those old posters. It's ironic as that was one of the darkest times in the recent history of China. I like that twist - the idea that everything looks fine but it isn't. In one of my pictures a girl is wearing a T-shirt that says 'It's All Good In The Hood'. But it isn't all good - she is standing in Tiananmen Square, where the massacre occurred.'

Horizons, by contrast, is set in rural Hunan province. Zhang's parents were translators from Guangzhou who were sent to the province to work as farmers during the Cultural Revolution. Zhang was born in Guangzhou - her pregnant mother returned to the city so she could be born there - but she spent the first years of her life in the countryside. The portraits feature young female children crouching down and gazing at the camera with a forceful, inquisitive stare. The idea was not to document rural life, says Zhang, but to record the subjects' first experience of being photographed.

'I thought that recording this first encounter with the camera was a bit like recording China's first encounter with the West,' she says. 'It was an interesting moment to capture. Children are powerful creatures. I like to capture the powerful innocence in them. They look at you in a certain way - their look can be very penetrating. They don't know anything about the outside world but they can still see right through you.' Zhang wanted the pictures - they were blown up to a large size and exhibited outdoors in Vancouver in 2009 - to empower her subjects.

'Female children from rural areas are a repressed group. They are not wanted - their parents want boys. Sometimes they are just abandoned. They don't have money, they don't have social power. Their parents won't educate them, so they might end up immigrant workers in the T-shirt factories. I wanted to empower them with my photography. They are crouching down, poised ready to jump. There is a power in the way they are posing.'

The series Daddy & I looks at the idea of China's transformation through the prism of the US. It depicts young mainland girls adopted by American families posing with their Western fathers.

'They show real father/daughter relationships,' says Zhang. 'Most of the girls [went to the US] when they were very young. They are Americans - the only Chinese thing about them is their looks.

'I wanted to examine the idea of the modern family - what does it mean to be a family when the members are from different cultures and backgrounds? Also, I want the girls to represent the growing power of a developing country. The white Western man represents the established power, the young Chinese girl the new one. The works show the changing power relationships. When the girls grow older will they rebel? When China grows older, will it rebel against the established power structure?'

Zhang's perceptions of the mainland have been formed by an international perspective. She thinks that growing up in a rural area has given her a sense of freedom. She attended the Central Academy of Fine Arts in Beijing to study painting and became interested in photography. The academy didn't teach photography so she moved to London where she earned a degree in photography at the Royal Academy of Art. She now lives in Brooklyn, New York.

China's integration with the outside world has irrevocably changed its art scene, she says. Some artists are following a commercial path to sell works to the West, others are integrating Western styles and techniques into their work. But, as it has done for centuries, China will absorb the new influences and Sinofy them, Zhang says. 'The character of the Chinese is to observe other cultures and take them into their own culture. We make our own versions of them. Like capitalism - we have given it a Chinese character. It even happened with dynasties, like the Mongol Yuan dynasty. They fell in love with Han culture and were absorbed by it.'

She adds: 'The West will watch what China is doing, and be influenced by it. You can already see that's starting to happen in some areas of the art world.'