Transmigrating Into A Female Side Character As A Prodigal Doctor - Chapter 61 - Gu Shen Gets Off Work Early For Yan Xi

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Zhang Ruo Chen was the sole male heir of one of the nine emperors of the Kunlun Field. Ruo Chen’s father was known to all as the “Enlightened Emperor”, however Ruo Chen didn’t just leech off his status as emperor’s son. He proved himself to be a dragon amongst men, possessing a heaven defying body, and managing to cultivate to Greater Perfection within the Yellow Horizon Realm, at just the young age of 16.

But even though he stood at the summit of the younger generation and had a boundless future, he sadly died at the treacherous hands of his own fiancee at a young age.

Reincarnated 800 years later in the body of a young boy who shares his name, he found out his former fiancee already unified Kunlun’s Field and built the First Central Empire, and was now known as Empress Chi Yao… Empress Chi Yao—Her Majesty governed the mortal world and enjoyed prestige in all directions as well as an eternal life.

Zhang Ruochen stood outside of the Imperial Ancestral Temple, looking at the statue of Empress Chi Yao, and the flames of hatred burned in his heart. “After I practice for 13 years, I shall send the empress to her doom!”

- Description from Novelupdates

After his soul transmigrated into the world of Teyvat, Luo Qing was selected to become the new Trainee Fatui Harbinger, and he was about to be sent to Liyue on a diplomatic mission (to cause chaos). To his surprise, he awakened a “Frustration Value Collection System” — as long as he frustrated others, he could collect frustration points, which he could use to participate in a lottery.As he stared at the list of items in the lottery interface, Luo Qing fell deep in thought:“Spirit Speech: Time Zero,” “Multi-Shadow Clone Technique,” “Thunder Breathing Style,” “Golden Experience Requiem,” “Railgun,” “Gomu Gomu no Mi...”Why on earth were these things appearing in the world of Teyvat?!Given the notorious reputation of a Harbinger, Luo Qing knew that if he didn’t grow strong, he was certainly doomed to a miserable end. Thus, his style became... increasingly abstract...---Years later, to prevent the infamous Fatui Harbinger, Luo Qing, from causing havoc everywhere, the people and political leaders of the Seven Nations united to issue a formal protest to Snezhnaya.In response, the Fatui in Snezhnaya issued an official statement:“This Harbinger is only a trainee. He has been dismissed.”

Before the rebirth, Gu Qingyao wanted to marry him but did not dare to marry. After the rebirth, Gu Qingyao, with the space materials in hand, all day planning to marry him with a huge dowry.