"When the speed of an object approaches the speed of sound, it will gradually catch up with the sound waves emitted by itself. At this time, due to the compression of the air by the mecha itself, it will gradually accumulate on the windward side of the mecha and its nearby areas, and finally form a sudden change surface of physical properties such as pressure, temperature, velocity, and density in the air - the shock wave surface. ”

"The shock surface will increase the resistance of the air to the aircraft, commonly known as the sound barrier."

"The shock wave surface formed by the mecha entering supersonic flight is a highly concentrated surface of acoustic energy, so it is also called a sound cone. The sound cone is a short, extremely strong explosion in the sense of hearing, so it is called a sonic boom. Supersonic flight compresses the surrounding air, causing the water vapor in the air to condense into clouds, so it is called a sonic boom cloud."

Huo Yuhao held a textbook written by himself in his hand and explained the course to the people below. However, outside the door of the soul guide research room on the side, there were suddenly several knocks.

"Knock Knock"

The door of the soul guide research room was opened, and it was Lin Jiayi, the teaching director, who walked into the soul guide research room. This teaching director, who had a very high status in the Sun Moon Royal Soul Master Academy, saluted Huo Yuhao at this time, and then motioned for him to come out.

Huo Yuhao nodded, and explained to these students to understand the knowledge points he had just explained, and then walked out of the soul guide research room.

"Director Lin, is there something wrong?"

Lin Jiayi coughed lightly with some embarrassment, and his face also showed some reluctance, and said to Huo Yuhao: "Mr. Huo, Zi Shengjun has summoned you to go to the Hidden Dragon Soul Mentor Group as soon as possible. ”

"Oh?" Huo Yuhao was also a little surprised when he heard this, he originally thought that there would be a month before he took office, but he didn't expect it to be so urgent.

"That's it, I've compiled all this theoretical knowledge in the past two weeks, you can hand it over to Elder Kong and the Hongchen Hall Master, as well as other high-level soul masters of the Mingde Hall for study, it shouldn't be a problem for them." Huo Yuhao took out a stack of thick materials from his storage soul guide and handed it to Lin Jiayi.

Lin Jiayi took these materials, as heavy as a mountain from Huo Yuhao's hands. He knew what these things represented, it was about Mingdetang, about the Sun and Moon Empire, and even about the future of the entire human race.

"Director Lin, please help me convey to the Hongchen Hall Master that the project of popularizing soul guide knowledge to low-level soul masters and ordinary people is still on top of the soul guide refining technology." Huo Yuhao said with a smile. "Everything from now on is up to you."

"I understand." Lin Jiayi nodded and said.

"By the way, Ling Tian stopped those friends of mine from the academy before, I originally wanted to use this matter to knock the academy out." Huo Yuhao saw the sweat slowly oozing from Lin Jiayi's forehead, smiled and waved his hand and said.

"Forget it, the three princes' henchmen have all been destroyed, and Ling Tian is nowhere to be found, so this matter is at that. However, I asked the academy to be kind to a few of my friends, and I hope that I will not hide any soul guide knowledge from them, and go all out to let them master the soul guide knowledge as soon as possible. ”

"Also, Teacher Wang Yan, who came from Shrek Academy yesterday, has now become the deputy director of the actual control soul guide department of the Sun Moon Royal Soul Master Academy, and those precious classics of Shrek Academy that he brought, please be sure to keep them properly and print them in large quantities, these things are the essence of the soul master cultivation method of the Wuhun Hall back then, and they will be of great significance to the future training of the academy."

Lin Jiayi bowed to Huo Yuhao with a solemn face at this time, and then nodded vigorously and said, "I understand, Mr. Huo, please take care!" We will be waiting for you in the academy to break the Mingdou Mountain Range and return with good news! ”

Mingdu, Prince Xu's natural residence.

"It's not that Uncle Zisheng is in a hurry, the main thing is that the situation in the court is turbulent now, and you have just come from the Douluo Three Kingdoms, so it is more beneficial for you to go to the Zisheng army to temporarily avoid the limelight and not show your edge too much."

In the reception room, Xu Tianran sat on the main seat and said with a smile to Huo Yuhao on the side.

"I see." Huo Yuhao also nodded with a smile and said. "But His Royal Highness the Prince, you have already entrusted someone to handle the matter I said before?"

"You said you want to create public opinion and completely pull Shrek Academy off the altar, so that it will lose the support of the people?" Xu Tianran said with some doubts. "It's hard for me to understand the key to this matter, Yuhao, you might as well say more."

"The art of war has clouds, with righteousness and harmony, and victory with wonder." Huo Yuhao said. "War is not only about the armed forces of both sides, but also about public opinion warfare and information warfare. Or, in this way, the will of the people can directly affect the enemy's combat power. ”

"That's true, it seems that Yu Hao, you also have some opinions in military affairs, and it is appropriate for me to arrange you in the army." Xu Tianran glanced at Huo Yuhao in surprise, nodded convincingly, and said. "In that case, you can tell me all the stains on Shrek Academy, and I will find a way to spread it to the Douluo Three Kingdoms, there are still many secret channels in our Sun and Moon Empire."

As the saying goes, money can make ghosts grind, and the Sun and Moon Empire sells rare metals and soul guides, and now the empire's wealth even exceeds the sum of the original Douluo Three Kingdoms. And with the shadows raised by the Sun and Moon Empire, there is already a foundation for winning a public opinion war.

"Shrek Academy has always advertised itself as beautiful, with a clear conscience, fairness and justice, so we naturally have to start from his so-called fairness and justice, and completely tear off his hypocrite mask." Huo Yuhao laughed.

"First of all, Shrek Academy has always advertised that it does not interfere in the internal affairs of the Douluo Continent, it is just an ordinary soul master academy, and it will not ask for any benefits from any country or force."

Huo Yuhao said this, took out a map made of soul beast leather, which looked very old, from his storage soul guide, and placed it on the table in front of him.

"Your Highness, please see, the Lima Plain belonged to the Barak Kingdom under the jurisdiction of the Heaven Dou Empire ten thousand years ago, and Shrek Academy was originally established in Soto City on the Lima Plain. Now the entire Lima Plain is under the jurisdiction of the Heavenly Soul Empire, but have you ever heard that the Heavenly Soul Empire has a city called Soto City? ”

"Not really."

Xu Tianran is very familiar with the map that originally belonged to the Douluo Continent, or the entire Sun and Moon Empire royal family can memorize almost all the cities that originally belonged to the Douluo Continent.

The shame of the Sun Moon Continent being forcibly merged into the Douluo Continent thousands of years ago was the biggest knot in the heart of the Sun Moon Empire's royal family. Even the princes and princes in the royal family who are waiting for death to eat and wait for death regard dominating the Douluo Continent as their greatest wish.

"Hehe, His Royal Highness the Prince, it's not that the city of Soto City has suddenly disappeared, in fact, today's Shrek City is the original Soto City!" Huo Yuhao laughed.

(End of chapter)