US carriers haven't used steam in a long time, they've been electro magnetic, the chicoms have been trying to copy it, it's taken them several years without good results. We'll see if they've actually got the bug worked out.... You're behind on your info, that was in print several years ago.At the level of an aircraft carrier, copying will actually be counter-productive. It's much better to make your own.
China's first carrier is a modified Russian heavy cruiser turned into a carrier. Their second is an improvement on that but still derived from that design. They are not happy with those carriers because they don't have a catapult.
That means their planes can only take off with half their weapons and half the fuel. The J-15 is the largest plane to be a used on a carrier anyway... it's big and heavy.
It was a no brainier to make a carrier WITH catapults. And they did not copy the US Navy's steam catapults. These are electric.