The Military-industrial Scientific Research System of the Academic Master Chapter 799

Chapter 799: Emails that influenced the entire history of mathematics

In the previous letter sent to Chang Haonan, Li Yabo had already expressed his hope to use structural mechanics as a research field.

However, "structural mechanics" is still a huge scope after all, and most people can only choose a more specific direction of specialization from it throughout their lives.

Let alone a mere graduation project.

Of course, under normal circumstances, for undergraduate students, they are just handed over to a certain senior brother or sister, and they can get started while getting familiar with the research group and project, and then it is almost over.

However, as Chang Haonan's first disciple, Li Yabo's treatment is naturally extraordinary—

Chang Haonan is going to take him with him personally.

The kind that starts with formulating a training plan.

But at present, Chang Haonan only has one turbofan 10 project left at hand.

Li Yabo is still just an undergraduate after all.

˜Whether from a capability or confidentiality perspective, it is not suitable for him to be directly exposed to a project of this level—

Chang Haonan's direct participation in the August 3rd Project was a special situation after all, and it cannot be regarded as a regular occurrence.

So, just let the other party choose.

Anyway, with Chang Haonan's current status in the Science and Technology Commission system, he can get projects immediately as long as the direction is not too outrageous.

And Li Yabo did not disappoint.

Such a specific and targeted answer has obviously been considered long ago.

Composite material thin-walled boxes are also a subject with a very wide range of applications.

And very prophetic.

The "box" here is not limited to horizontal and vertical hexahedrons, but also includes cylinders, ellipsoids or other irregular shapes.

Basically regarded as the main research direction in the aerospace field in the next 20 to 30 years.

Like the fuselage of large passenger aircraft, the casings of rocket missiles, etc., the amount of composite materials will gradually increase to reduce the structural weight.

For example, when Eurocopter designed the NH90, it had already considered using a large number of composite materials in the fuselage.

It's just that the operating environment of helicopters is indeed quite harsh. Giving up ease of maintenance and damage resistance for the sake of a small amount of weight is a waste of watermelon, so Chang Haonan stopped it.

However, at the end of the 1990s, the application of composite materials was still a well-established frontier field. It is really surprising that a senior undergraduate student could choose it so accurately.

“Tell me why you want to go in this direction?”

Chang Haonan asked.

“Didn't I work on a small UAV structural design project with Teacher Li Guang? At the beginning, because the engine power provided by Party A was insufficient, Teacher Li considered completely using carbon fiber instead of metal to make the body of the UAV. "

“But in the end, because no research in this area has been done before, Party A was worried that the design risk would be too great, and of course there were cost issues. In the end, magnesium-aluminum alloy was used.”

Chang Haonan was speechless for a moment.

At the beginning, it is indeed risky to use a 100% composite body.

At present, Huaxia aircraft generally use less composite materials, and their main applications are secondary skins and other locations that do not bear high loads.

“So...how was the problem of overweight being solved in the end?”

This question is purely out of curiosity.

The intersection between Chang Haonan and Professor Li Guang was limited to the time when they were just reborn. The other person served as a judge in Professor Liu Hongbo's class and was shocked by his design plan.

So the former is not quite sure what the drone project is about.

“Not solved.”

Li Yabo replied:

“Party A later replaced the piston engine in the original plan with a more powerful lightweight turboprop, so the overweight was also overweight. That project did not have high requirements for us. Basically, it only needed to be able to fly..."

"Fine."

Chang Haonan never expected that it would end like this:

“Now that you are sure, let's go in this direction.”

After speaking, he lowered his head and thought for a moment:

“However, scientific research must be carried out step by step. Research on composite material structures is a brand new topic for our country...and the world, so we cannot start large-scale projects right away..."

“I have some relevant information and literature. I will give you a look today to familiarize yourself with the basic research methods of materials mechanics and structural mechanics. I will officially start after I apply for the project.”

"good."

After talking about the project, Chang Haonan asked Li Yabo to go to Liu Chenchen to get a stamp to prove that he had indeed entered the research team and completed the topic selection process.

Graduation project is regarded as a “course” that takes up more than ten credits in the training program.

If the topic opening link is missing, although Chang Haonan can handle it, it is still more troublesome.

“Huh…” Chang Haonan finally breathed a sigh of relief when he saw Li Yabo's back disappearing from the door, almost revealing that he had forgotten about him. Then he returned his attention to the computer screen and began to think about how to write a reply to Perelman.

A few days later.

Moscow, Steklov Institute of Mathematics.

Gregory Perelman, who has been working for more than ten hours straight and is about to go home for a break, opens his mailbox as usual and prepares to check if there are any new emails that he needs to deal with.

This is his personal habit.

Plan the next day's work before you leave work the day before, rather than waiting until after you arrive at work that day.

In the past ten years, this has always been the case, and it is unshakable.

“Invitation to Princeton's Annual Mathematics Meeting…”

“Millennium Mathematics Prize…”

“The invitation for a review of the Journal of Mathematics… ha… seems to have been affected by the actions of the Annals of Mathematics. They are really stupid. If they continue like this, their influence will never be as good as that of the Annals of Mathematics…”

Perelman moved swiftly into the recycling bin, one after another that he deemed unimportant.

Even included a notice awarding him the Millennium Mathematics Prize and informing him to go and receive the award.

He has no plans to leave Russia in the near future.

At least I won't leave because of these “trivial” things.

What Perelman loves is the beauty and mystery of mathematics itself. After successfully proving the soul conjecture a few years ago, he discovered that if he won an award for solving a certain mathematical problem, it would dilute his ability to solve a certain mathematical problem. The joy of the problem itself.

From that time on, he refused to accept any personal awards, and even gradually tended to publish his results directly in the public rather than in the form of papers.

"etc…"

Just when Perelman thought tomorrow would be another boring day, he suddenly caught a glimpse of an email he had been waiting for.

To be precise, it's a reply letter.

“It's finally here…”

He clicked quickly.

About a month ago, he was shocked when he saw this paper published in the Annals of Mathematics.

There is actually another person in the world who is solving the application problem of Ricci flow in three-dimensional conditions with a similar idea to him.

Moreover, he was half a step ahead of him.

So, after getting some inspiration from it, Perelman wrote his thoughts in an email and sent it to the author of the paper.

For more than a week, he did not receive a reply.

until today.

【Dear Professor Perelman, thank you for your letter. The content of the email has greatly inspired my research...】

Perelman skimmed over the polite remarks.

Fortunately, Chang Haonan's reply style was similar to his, and the second paragraph went directly to the point:

【I have verified your conclusion and there is no problem, but the derivation process of the theorem seems to be more concise and direct...】

[The function of the non-local collapse theorem is that it can give a local injective radius estimate, and the Ricci flow after surgery can still satisfy this property. In this case, based on Hamilton's injective radius estimation theorem, it can be derived For the marked (Mk, gk(t), pk) that satisfies certain conditions, there must be a convergent subsequence...]

The expression on Perelman's face changed from relaxed to solemn, and then to excited...

He quickly pulled out a ballpoint pen and a piece of paper from the desk next to him, lowered his head and began to calculate quickly.

“That's right...this verification process should be more straightforward...”

About half an hour later, Perelman looked at the calculation process that only used one positive and negative space, and said to himself excitedly.

Although the content of the theorem proved by Chang Haonan is exactly the same as what he sent before, the process is much simpler.

“In this case, I don't have to worry about those guys not being able to understand my proof process…”

Perelman muttered as he took off his coat and scarf and returned to his desk.

Obviously, the plans to get off work were ruined.

“Perhaps, I should go to China myself?”

He looked at the signature of CHANG Haonan at the bottom of the email on the computer screen, and had long forgotten the idea that he was not planning to go abroad in the near future.

(End of this chapter)

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