What do the circular icons on planes and ships in China stand for?

Neither of them is right downstairs. Those two marks, if affixed to the product, indicate that the product has radioactive marks. That's right.

However, please note that the above signs are all on the hull and the first flight plane (this can well prove my words, that is, China's first generation carrier aircraft J-15 can see yellow and black circles when taking off and landing for the first time on the aircraft carrier and Yun -20' s first flight), and the only function of this sign is to locate and capture the camera equipment.

If you don't believe me, you can look at the first take-off and landing map of J-15 on the aircraft carrier.