Chapter 187 The End of Sonar
Hu Xinrui was not the only one who came, but there were also two other scholars, both of whom looked older than Hu Xinrui.
Hu Xinrui only has thinning hair, while of the two, one has Mediterranean hair and the other is completely bald.
The consequence of total baldness is that although he looks like a young man in every aspect, he looks older than a middle-aged man.
Chen Yuanguang couldn't help but think, is this the price of becoming stronger? That would be too painful.
"Yuan Guang, this is Professor Wei Rongzhao. He is also a direct disciple of Academician Wang Dezhao. Wang Dezhao is the founder of our country's national defense acoustics." Hu Xinrui introduced.
Wei Rongzhao stood up and shook hands with Chen Yuanguang: "Academician Chen, I have long admired your name." After saying that, he said no more.
Hu Xinrui continued: "This is Professor Jiang Zhonghua, a professor at Jinling University.
He is also a professor who is doing cutting-edge applications of topological materials in the field of acoustics. We have considered the direction you are doing. It’s too cutting-edge, and the two of us may not be able to understand it.
So I specially asked Professor Jiang to come over and provide us with some help.”
After Jiang Zhonghua got up, he also made general greetings.
Chen Yuanguang was more interested in Jiang Zhonghua’s research direction: “Professor Jiang, what specifically are you doing?”
As an academician, Chen Yuanguang’s status and energy are enough for him. Ask questions from a mentor-like position.
“Mainly condensed matter physics, such as thermoelectric effects, photonic crystals, topological effects in wave systems, strong correlation effects in optical systems, etc.
I took over a national key project before Scientific research plan, cutting-edge application research of metaacoustic materials. This project is highly related to submarine stealth.
Professor Wei was worried that you were using topological materials and he would not be able to follow your ideas by himself, so he called me up. ”
Only when enough funds are invested in scientific research and the scientific research team is large enough, can we have corresponding talents in each subdivision.
Limited by limited resources, China has The strategy in scientific research is to cast a wide net. Anyway, there are people in every field, not too many, but there must be. Once there is a breakthrough in this field, whether it is domestic or foreign, then more resources will be invested.
This is a very realistic strategy at the moment.
Such a strategy can ensure that one does not open up too much of a gap.
After hearing this, Chen Yuanguang said: "Okay, I understand."
This is the bad thing. You have to tell the other party all your thoughts during the material development process, so as to cover up the reason why you have come up with these technologies. rationality.
Actually, Chen Yuanguang doesn’t want to talk too much, because the more he talks, the easier it is to lead to new problems, and it is very difficult to explain these new problems using the existing theoretical framework.
“We all know that the acoustic coating materials used on submarines are mainly divided into two categories according to their functions: decoupling tiles for sound insulation and anechoic tiles for sound attenuation.
< br>The main function of the decoupling tile is to reduce the radiated noise and self-noise of the submarine. The anechoic tile reduces the target intensity characteristics of the submarine and the reflection of active sonar sound waves.
But in recent years, with the deepening of research in the field of materials, some new sound-absorbing coatings actually have both functions.
Two professors, since you understood the research direction I was doing before coming here, you must know something about acoustic metamaterials and one-dimensional superconducting materials in the room-temperature superconducting scheme? "
Jiang Zhonghua knew what the other party was talking about. It was referring to the article Chen Yuanguang published in the special edition of Nature and Science when room temperature superconductivity was discovered.
That article was published in the past two years. , firmly occupies the throne of the most important paper in the entire materials science, and a large number of laboratories around the world are exploring along the direction of Chen Yuanguang.
Although no one has truly reproduced room temperature superconducting materials, there are many. Few interesting results have been produced, especially the idea of using magnetic field control technology to open pathways at a microscopic level, which has been applied to many cutting-edge materials research
In a sense, the theory of room-temperature superconductivity has guided the research on materials science in the past two years from a higher level.
“I have read it no less than ten times. When I read many papers in the past two years, they all quoted some of the theories in your paper.” Jiang Zhonghua said.
After listening, Chen Yuanguang nodded and said: "That's good, then what I'm going to talk about next should not be that difficult to understand.
We still have to talk about the materials used by Xiaomi Ultra It is a piezoelectric metamaterial
But it is composed of two parts of materials, namely the piezoelectric material responsible for sound transmission and the piezoelectric material responsible for noise reduction.
The latter is what we are going to focus on today.
When elastic waves in a specific frequency range propagate in a structure, elastic wave band gaps occur.
These band gaps can suppress and absorb elastic wave propagation in the relevant frequency range.
The elastic band gap of the acoustic metamaterial we use is mainly generated by two main mechanisms: Bragg scattering mechanism and local resonance mechanism.
Therefore, according to the different principles of band gap generation, acoustic metamaterials can be divided into Bragg scattering phononic crystals and local resonance acoustic metamaterials.
We mainly use this principle to construct the acoustic metamaterials we need, and use its band gap characteristics to achieve silencing.
Its most prominent feature is that the hard boundary of the sound field can meet the needs of underwater pressure. Sound waves in underwater equipment flow from the seawater environment to the underwater equipment. The sound pressure is zero through the hard boundary. "
After listening to it, Jiang Zhonghua immediately captured the key point: "Is it similar to a permanent magnet structure?
The unique elastic wave band gap characteristics of the permanent magnet structure prevent elastic waves from propagating within the band gap frequency range it covers, so permanent magnet structures are used to design underwater ships. ”
“Yes, you can understand it as the application of this structure at the microscopic level.
Because the viscosity of the elastic material can dissipate the mechanical energy of vibration, it absorbs sound waves and passively reduces noise.
So this time we used the above principles to derive a new composite material with both viscoelastic and piezoelectric properties.
The piezoelectric material used in Xiaomi cars has gone a step further. This new piezoelectric material can be used underwater.
When we use this material for submarine coatings, we apply a controlled periodic voltage to the piezoelectric material layer to generate corresponding stress to eliminate reflections, thereby emitting sound waves with the opposite phase to the vibration.
It should be able to fundamentally solve the problem of insufficient concealment of submarines in our country.
The best fact is to adopt the method of periodically distributed piezoelectric patches, bond these piezoelectric patches to the surface of the main structure of the submarine, and then the shunt circuit works with the patches in a self-inductance mode to build multiple band gaps. It is possible to cover the bandgap band widely enough and achieve a good silencing effect. "
Chen Yuanguang stood up and projected the patch structure he designed on the screen in the conference room.
"Because I don't have the specific structural diagram of our country's submarine, so I I just used something with a similar shape.
I will talk about my algorithm for using this piezoelectric material patch, how I calculate it, how to design the current, and how to apply the patch to make it more reasonable and maximize the noise reduction effect.
You can directly use my ideas to compare existing submarine models and then design them.
In this way, we can improve our immediate combat effectiveness as quickly as possible. "
After Chen Yuanguang finished speaking, Jiang Zhonghua and Wei Rongzhao's eyes shone, waiting for Chen Yuanguang to give them a lecture.
Wei Rongzhao even saw the shadow of his mentor in Chen Yuanguang, and the master's style was clearly visible. .
This class lasts for five days. In order to consider their acceptance, Chen Yuanguang’s progress is not fast. It’s not that they don’t work hard, but there are too many cutting-edge things that Chen Yuanguang needs to make up for. Maybe they just mentioned a term unintentionally. For them, they have to read literature at night until three in the morning
In the design of piezoelectric material patch structures, a large amount of topology content makes them even more miserable.
So much so that Jiang Zhonghua complained privately: "I think I should find an expert in topological fluid dynamics? I feel like my CPU is going to explode."
Jiang Zhonghua is that person He was completely bald, but he still had the heart to joke, which made Wei Rongzhao feel even more bitter, "The last bit of hair that I managed to save will probably fall out after classes are over in the past few days."
A week later, Director Zhao Come to pick them up and talk to them one by one in the conference room: "Professor Jiang, you should know the importance of this technology?"
Jiang Zhonghua nodded. He was also selected after layers of reviews. In terms of reliability, It's very high.
"You will need to change jobs in the future. Someone will contact you later. You need to go to your new job immediately. The contact person will help you with some trivial matters."
Jiang Zhonghua nodded: "Okay, I understand."
Director Zhao asked again: "What do you think of Academician Chen?"
Jiang Zhonghua knew what the other party was asking, thought about it and said, "Academician Chen is definitely the material. He is a master in the field of science.
He has a lot of cutting-edge knowledge about condensed matter physics, magnets, crystals and other materials at his fingertips, and he has some knowledge of the underlying principles, even among masters. , he should also be the one with the most extensive knowledge.
More importantly, he can put cutting-edge knowledge into his knowledge framework system and then output new content.
This can only be achieved after mastering this knowledge to a certain level. As for my attainments in mathematics and physics, I don’t know how advanced they are. "
After Jiang Zhonghua finished speaking, he sighed: "People are different after all, although I can't understand why Academician Chen's scientific research results can be so rich.
Looking at some self-media on the Internet, it is said that Academician Chen has obtained alien technology. I had similar suspicions before, but after dealing with Academician Chen, I don’t think so.
Because his knowledge does not go beyond the existing theoretical framework, I can know what each point is, or can find the source, but we have never thought of using it in this way.
My judgment is that Academician Chen is the top genius I have seen so far. "
Director Zhao did not comment after listening: "Okay, I understand, remember the confidentiality agreement. ”
This has been a routine action in the past two years. Every scholar who cooperates with Chen Yuanguang will be asked this question.
Because the results are so amazing, Yanjing has various opinions , There are those who protect Chen Yuanguang, and there are naturally those who want to make a profit and find out the source behind it.
The latter feel that Chen Yuanguang's scientific research results violate objective laws and do not believe that people can be so genius.
"We will stand firmly with Amerikan." Neon emphasized the past argument again.
At this critical moment
"Is Kishida crazy? Has he started to do whatever it takes to keep his position?"
A lot of opposition filled the neon On major social media, Kishida’s approval rating has reached a new low.
Under such an environment, a military industry exhibition was quietly held in the west of Shudu.
"Aren't you making dumplings just for the vinegar?"
"Yes, but now that the vinegar is valuable, why don't you let it out to scare them?
Don't scare them anymore? They, what if Neon is really gone?
Lao America is gone. The situation at home and abroad is very good now. Europe and we are in an unprecedented honeymoon period. We have a lot of trade exchanges and technological research and development.
If the United States really forces us to quit at this time, then we will really be dragged into the water by them.
This good situation will soon be ruined.
The EU is not as obedient as 4v. The United States is worried that there is no reasonable way to prevent the world's major economies from trading with us.
We can’t give them words at this time. ”
“But can this new 039C scare Neon? ”
“Whether it works or not, you have to give it a try.
039C is not the key, the key is to make them realize that as long as we give us time, we can drive the submarine to their offshore waters without being discovered by them, and send a missile to Tokyo.
To be honest, from this perspective, I am really looking forward to the fight. "
"There is no way, the big guys don't want to fight, your will is useless, I also want to see 4v get fucked, why don't we fight this traitor. ”
The core purpose of the Shudu Military Industry Exhibition is to display the new 039C stealth conventional submarine designed based on new piezoelectric materials.
Although it has not been officially installed yet, according to the progress, it will be by the end of this year We will definitely be able to complete the commissioning of the first new 039C
Therefore, it is not too early to exhibit.
The Shudu Military Industry Exhibition invites more than 50 countries from around the world to participate, mainly from Asia, Africa and Latin America.
Just when everyone thought this time was no different from before, the Huaguo Shipbuilding booth was crowded with people.
Because there is a brand new submarine in the center of Huaguo Ship’s booth, with the logos of Huaguo Ship and Light Armor Aerospace next to it.
The parameters clearly read: at a traveling speed of 12 knots, the noise level is 50dB.
This made the booth full of foreigners, and everyone was discussing the authenticity of this incident.
The difference in appearance of this submarine model is obvious to everyone.
“Oh shit, the Americans won’t be able to sleep.
A submarine with 50 decibels will completely lose its sonar.”
Generally speaking, the ocean background noise is at 100 It floats around 110 decibels, while the noise of federal nuclear-powered submarines is about 110 decibels, and the noise of China's nuclear-powered submarines is 160 decibels. In recent years, the noise of conventionally powered submarines has been reduced to 110 decibels for the first time.
Simply put, after reducing it to 110 decibels, it will make it difficult for submarines to be detected.
Once it drops below 70 decibels, it is almost impossible for sonar to detect it, and at 50 decibels, all existing sonar can be eliminated.
“Are the Chinese people warning the Federation and Neon not to act rashly in this way?”
“Although I know that the Chinese people have developed rapidly in science and technology in recent years, but whether 50dB Too advanced? ”
“It looks great, can we buy it?”
(End of this chapter)