Buying a Chinese Unicom Sim card at Pudong Airport

Hi,
I would like to know if we can buy a Chinese Unicom Sim card when we arrive at Pudong International.
We will be arriving at 6.30pm at terminal 1 and would like to be able to puchase this sim card before we leave the terminal.
Will any phone shops selling Unicom sim cards still be open at this time
Many thanx
Maggie