Air China will replace its two daily 747-400 flights between PEK-LAX with the 777-300ER.... The first 773ER will land at LAX on the February 1st. replacing the daily night flight)... In june, Air China will replace the other 747 flight.
It seems Air China is very proud of their 777-300ER product, I've seen that advertisement on about 3 diferent newspapers.
I believe their other 777-300ER long-haul destination is FRA