The Ming Dynasty Double-Crossed the Door, but I Actually Ended the Little Life?

Su Bai returned to Dragon Kingdom in 2001 and became a graduate student at Dragon University. Repair frigates, research nuclear-powered aircraft carriers, and analyze key technologies. But a person's power is limited after all. Even if Su Bai does scientific research for ten more lifetimes, it will be difficult to help the Dragon Kingdom revive and rise. Fortunately, he suddenly awakened to the double-traveling door system of all realms and could travel to the world behind the door at will. [Ding, congratulations to the host for drawing a double portal in the Ming Dynasty! Ming Dynasty double door? Su Bai's eyes suddenly lit up, and a bold idea came to his mind: "Take the knowledge learned by future generations to the Ming Dynasty, build roads, and build steam engines. While helping the Ming Dynasty improve its national power, it can also absorb the national fortune value required by the system!" Therefore, while Su Bai was building the Ming Dynasty, he was also breaking through the stuck technology for the Dragon Kingdom and helping the Dragon Kingdom rise. A few years later, seeing that the military technology of the Ming Dynasty had matured, Su Bai rubbed an atomic bomb in his hand and pointed the test site at the Japanese country...