I don't believe these have been revealed before. Apparently, this is a photo taken at a handover ceremony for the Carrier AWACs test platform, which according to the second photo, took place on August 13th, 2009.
The words on the backdrop translates roughly as "Handover ceremony for the critical technology demonstrator for the carrier-borne early warning platform". At least that's what I think is the gist. However, I'm unsure about certain technical terms employed here.
Here's the somewhat literal translation just for kicks: "Carrier-borne AWACs platform critical technologies verification prototype, intense(?) experimental aircraft handover ceremony".
It's the delivery of a structural test article of the prototype aircraft. Although confusingly it did not use the term "舰载" for carrier-bourne. "海上" literally means maritime and couple Gaoxin projects aircraft could fit that description.