Into Unscientific

"."'

in the house.

Zheng Tao finished speaking.

At the scene of the interest group, where there were not many noisy conversations, the quietness dropped a lot again.

It is clear.

After all, this is the first meeting for everyone, and most of the members are quite restrained, not daring to speak easily.

See this situation.

Zheng Tao didn't feel disappointed or surprised, but smiled at the crowd as usual and said:

"Comrades, we are all old acquaintances who have known each other for a while, so there is no need to be so lucky?"

"The main purpose of our group is to make no distinction between seniority and inferiority. Everyone can speak freely, just like everyone did in school back then. There is no need to have too much psychological pressure."

"Well, is there any comrade who volunteered to fire the first shot?"

Say it.

Zheng Tao then turned his head and winked at a girl sitting in the corner calmly.

This is a babysitter arranged by Zheng Tao in advance. In order to avoid being neglected, Zheng Tao also specially chose a female comrade.

But just as this Thor was about to make his debut.

Diagonally opposite Zheng Tao's seat.

A boy who wears glasses and has a single ponytail behind his head, who looks a bit literary, raised his hand first:

"Comrade Zheng Tao, then I will have the audacity to be a stepping stone and give everyone a head start."

Zheng Tao was startled for a moment, but soon his expression brightened:

"No problem, no problem, Comrade Fang Zhong, if you have any questions, just ask, let's work together."

to be honest.

Zheng Tao was indeed a little surprised.

At first, he thought that someone would take the bait only if the babysitter he had arranged appeared on the stage, but he didn't expect someone to jump out on his own initiative.

It's like fishing guys are ready to buy fish in the market, but one fish automatically jumps into the net.

this is really

Very good.

As for the boy who spoke, Zheng Tao also knew him.

This person is called Fang Zhong, and he graduated from the famous South China Institute of Technology, which is later known as South China University of Technology.

In addition to his high academic qualifications, Fang Zhong is also very good at the melodica. Every time the educated youth at the base hold various gatherings, the organizers basically ask him to help with the accompaniment.

Then a group of male singles sat by the bonfire, thinking about the beauty of love in the melodious harmonica, and then continued to be single the next day.

Eyes return to reality.

I don't know if it's because of the long-term "performance" experience.

Fang Zhong looked very calm under the gaze of the crowd at this time, quite a bit of a social cow's posture.

He adjusted his glasses, coughed lightly, and said:

"Comrades, the problem I want to share with you is actually a phenomenon I discovered at work a few days ago."

"I'm sure you all know that I'm currently assigned to work in the literary and art sideline team of the base, mainly to help the team."

"Recently, the sideline team is making stage preparations for the stage commendation meeting in the factory. In addition to the banners, the stage will also hang a few rows of small balloons to enliven the atmosphere."

"About three days ago at noon, when I was blowing up the balloon, I suddenly discovered a situation, that is, the balloon will be more laborious at the beginning, but it will become easier and easier later on."

Speaking of which.

Fang Zhong couldn't help rubbing his temples, sighed and said:

"I am a person who likes to be more realistic. When I encountered this situation, I suddenly wanted to understand the principle of it."

"So in the past few days I have been thinking about this question, what is the reason or principle that caused this situation?"

"But after thinking about it, I can't think of a reason in the end."

"."

Fang Zhong's reputation and popularity in the youth circle of the base are very good, otherwise he would not have the confidence to say [presumably everyone knows] such a thing.

In addition, the question he asked was indeed a little new, and it was a small detail that many people didn't pay attention to at all.

So soon.

There were muffled murmurs in the house.

After a while.

A tall, thin boy with a sallow complexion and a somewhat malnourished look raised his hand:

"Comrade Fang Zhong, could it be your illusion?"

"After all, according to the gas pressure formula pV=nRT, it seems that the situation you mentioned should not happen."

Hearing what the tall and thin boy said.

Several people at the scene nodded in agreement.

The gas pressure formula pV=nRT is a concept that is widely popular even in this era—relative to the level of college students.

According to the formula, it is not difficult to judge that the more gas the balloon is, the harder it is to blow.

But Fang Zhong was silent for a moment when he heard the words, and shook his head resolutely:

"It shouldn't be my delusion, because I also asked several comrades who blew up balloons together, and everyone also said that this happened."

"That is, the bigger the balloon is, the easier it will be to blow up."

Say it.

Fang Zhong also took out a small balloon that was not blown up from his body, and threw it precisely in front of the boy:

"Comrade, this is the little balloon my team leader gave me after I worked overtime yesterday. You can try blowing it up."

"."

The tall and thin boy looked up at Fang Zhong, picked up the small balloon and blew it to his mouth.

inhale,

exhale,

call out.

The balloon soon began to grow slowly.

And just when the balloon swelled to the size of a grapefruit, the tall and thin boy's eyes suddenly revealed a hint of consternation.

Then he continued to blow two more times, and the balloon eventually became about the size of a basketball.

Then the tall and thin boy slowly opened his mouth, held the balloon with both hands, and let the gas in it puff out.

See this situation.

Fang Zhong couldn't help asking him:

"How? Is what I said correct?"

The tall and thin boy nodded silently.

During his attempt just now, what Fang Zhong said did happen.

That is to say, there is obvious resistance at the beginning, but the bigger the balloon, the easier it is.

Then several boys around him also tried it one after another, and they all found that the insufflation resistance of the balloon at the beginning is much higher than that in the middle and later stages.

And this is obviously a counterintuitive situation, so these educated youths at the scene immediately had a desire to discuss.

"That... I have a guess."

The one who raised his hand this time was a future boss, that is, Yang Fujia, who Xu Yun had recognized before, a future famous atomic energy scientist:

"Could it be that the wall layer is thicker and relatively compact when the balloon is not blown up, but becomes thinner and looser after blowing up, so it becomes easier to blow up?"

I heard this.

Zhou Shaoping, who was sitting across from him, thought for a moment, then quickly shook his head:

"Old Yang, your explanation is too life-like, and it is far away from the essence of physics."

"I think that if this phenomenon does exist, then it must have a deeper explanation. After all, everything is about science."

Xu Yun glanced at Zhou Shaoping.

Due to the problem of equipment accuracy, the physics community in this period has not yet developed the understanding of the microscopic field to the next level.

Therefore, most physicists firmly believe that everything can be answered through existing theories—especially the new generation of domestic physicists such as Zhou Shaoping and others.

This kind of cognition will continue until Gell-Mann proposes the quark model, and the physics community will find that they are not only a pile of dark clouds above their heads, but also the ground under their feet is illusory.

Of course.

It has not been a few years since Gell-Mann proposed the quark model, so in the theoretical physics circle of later generations, there is a very interesting nickname for the physicists of this period:

Candide at last.

Immediately afterwards.

A few more members have put forward their views one after another:

"Could it be a problem of tension? The surface of the balloon is deformed, so the tension changes?"

"It definitely has something to do with the tension, but what about other values? - Don't forget, the balloon will fly around when it is deflated, and there is usually a sense of sprinting at the end, which means that the ratio of tension to something must be different. changing."

"Will it have something to do with air resistance?"

"I think it has something to do with gravity."

The atmosphere at the scene became more and more lively, and even Zheng Tao and Lin Yu made some analysis in the end.

But after several discussions.

In addition to confirming that the situation should be related to tension, the rest of the guesses and judgments were quickly rejected one after another.

The result was chatting.

Just when everyone was a little stuck, a sentence suddenly sounded from somewhere on the table:

"Comrade advisor, why have you been silent? Do you understand the reason for this situation?"

Among them, the word "advisor" has been amplified a little.

As soon as this remark came out.

The originally lively scene suddenly became silent.

Swish——

Everyone's eyes locked on Xu Yun who was sitting in the wheelchair again.

It cannot be said that the person who spoke was hostile or had ulterior motives, but it was obvious that he was not convinced by Xu Yun's title of 'consultant'.

See this situation.

Zheng Tao couldn't help but cast a concerned and questioning look at Xu Yun, which meant clearly:

Can you do it?

Xu Yun replied to him with a hint of "Don't worry".

Then he turned to look at the crowd, and said succinctly:

"To tell you the truth, I am lucky enough to know this truth."

"."

No one made a sound at the scene, but the pupils of some members shrank slightly, looking quite surprised.

To know.

Except for Bao Zheng.

Although these current members are all under 30 years old, they are all graduates from prestigious schools, and there are even four of them who are international students—this still excludes the numbers of Xu Yun and Lin Yu.

In the eyes of most people.

Comparing them one by one, there may be a gap in ability between them and Xu Yun.

After all, many of them knew the principle of the damper beforehand, and they thought that there was probably a gap in knowledge between Xu Yun and Li Jue, who asked them to keep the matter of the weather Doppler radar a secret.

But on the other hand.

This gap is not so outrageous that all the people together can't compare with Xu Yun alone, and the three cobblers can stand up to Zhuge Liang at any rate.

Of course.

A large part of the reason for this kind of psychology is also because Xu Yun's age does not look too old.

If it were a young man in his fifties or sixties, everyone's attitudes would not be so complicated.

Seeing Xu Yun express that he knew the truth, Fang Zhong quickly asked:

"Comrade advisor, can I trouble you to explain the principle of this matter?"

"To tell you the truth, this problem has troubled me for more than three days, and I have to think about it for an hour or two every night before I can fall asleep."

Xu Yun glanced at this cool handsome guy, and didn't directly explain the principle, but asked him:

"Comrade Fang Fangzhong, right?"

"Before explaining the principle, I want to ask everyone a question."

Say it.

Xu Yun pointed to the deflated balloon on the table, and said:

"Suppose there are nine such small balloons and one large balloon in front of us, and they have the same volume, who can store more gas?"

"Is it a small balloon? Is it a big balloon? Or are there as many?"

I heard this.

Qiao Caihong, who was behind Xu Yun, blinked and subconsciously said:

"Comrade Han Li, do you even need to ask? Of course it's the same amount."

"wrong!"

As a result, as soon as Qiao Caihong finished speaking, Lin Yu on the other side shook his head:

"No, it's not that simple."

"Nine small balloons and one big balloon have the same volume as V, but it doesn't mean that their pressures are the same."

"According to pV=nRT, it can be clearly seen that once the pressure is different, the stored gas will also be different."

A question mark immediately appeared on Qiao Caihong's face:

"OvO?"

Xu Yun smiled at the silly girl, then looked at Lin Yu on the right, and said affirmatively:

"Comrade Lin Yu is right. This problem is far more complicated than it seems."

"Then Comrade Lin Yu, can you analyze the difference in pressure between the big balloon and the small balloon?"

Lin Yu thought for a moment, frowned and shook his head slightly:

"Intuition and logic tell me that the pressure of the balloon must be stronger, but I don't know the reason."

Xu Yun cast an approving look at the girl.

Which is stronger, a big balloon or a small balloon.

This issue will be left to later generations, and many people will definitely say it is a big balloon.

The reason is that the contraction force of the balloon membrane can be regarded as a spring system, and then a qualitative analysis can be done directly.

But in fact.

The problem is far from simple.

Indeed.

Naively, the tension σ should increase with the size of the balloon, that is, the increase of the deformation.

But don't forget.

While the balloon is inflating, 1/r decreases as the size of the balloon increases.

Therefore, if it is analyzed from the material level, it is necessary to establish a non-qualitative model.

This involves the hyperelastic constitutive of rubber, which must be applied to a generalized hyperelastic model such as the Ogden model.

But students who have studied thermodynamics in later generations should know it.

There is a more acceptable method of physical analysis for this problem other than a non-directional model of the material.

Think here.

Xu Yun organized some words and said to everyone:

"The difference between a small balloon and a large balloon is their size. As the balloon expands, its surface starts to get tighter and tighter, and there is always a tendency to want to retract."

"If the pressure of the gas inside the balloon is the same as the pressure of the gas outside the balloon, then there is no other force that can balance the resilience of this balloon skin."

"So the gas pressure inside the balloon is actually higher than that outside the balloon, or the resilience of the balloon skin compresses the gas inside the balloon."

Speaking of which.

Xu Yun asked Qiao Caihong to push the wheelchair to the edge of a blackboard and drew a picture with chalk.

The shape of the schematic diagram is very simple, and the intuitive description is just that.

Make a "yeah" sign, then face left horizontally, with an arrow on each fingertip of two fingers.

Then Xu Yun wrote an O at the intersection of the "fingers", and wrote an A in the middle of the arc connecting the fingertips:

"Everyone, please see that the point O here is inside the balloon, and A represents a very small square on the surface of the balloon."

"Because the balloon is inflated, the surface is not flat but has a curved curvature."

"As for the surface tension T, it is trying to flatten this arc as much as possible."

"In this way, isn't it obvious?"

See this situation.

Many members nodded subconsciously.

really.

There is a curvature on the surface of the balloon, which is an expression that elementary school students can understand.

Therefore, although the direction of the surface tension in the diagram is perpendicular to the radius R, it is not perpendicular to the connecting line from the center O of the sphere to the central point A of this small area.

At this time, if there is no other force, the film, that is, the surface of the balloon, will naturally not be able to maintain balance.

In other words.

There must be a pressure difference on both sides of the balloon skin to counteract the force of the surface tension T on the line OA.

Then Xu Yun wrote another derivation:

detF=λ1λ2λ3=1, where λi (i=1, 2, 3) represents the stretching ratio along three orthogonal directions.

Ψ=∑p=1Nμpαp(λ1αp+λ2αp+λ3αp3).

When p=1, α1=1.

Write Ψ=2μ(λ1+λ2+λ33).

Assume that the balloon on the curved surface belongs to the state of equal force in two directions, and is free in the x3 direction.

Then the Cauchy stress is written as σ3=P+∑p=1Nμpλ2αp=0. (Note: I'm not sure if the Cauchy stress has a fixed formula at this time, let's take it as it is, after all, this plot is very important)

Let the balloon have an initial radius R and an initial wall thickness H. After deformation, the radius is r and the wall thickness is h.

Then the final formula is:

p=2σhr=2λ3σHR=2HR∑p=1Nμp(λαp3λ2αp3).

this time.

A look of enlightenment appeared on the faces of more people at the scene.

It is not difficult to see from this formula.

The volume element δl/Rl is in the middle of the formula, that is to say, no matter what the value of x, t, ya, etc. is, δl/R remains unchanged.

In other words.

At this time, both sides of the equation are divided by δl by the specific value, and then substituted into pV=nRT.

will find

P=T/R will first decrease and then increase.

write here.

Xu Yun put down his pen, spread his hands, and said to everyone:

"Then the answer is obvious."

"As the volume of the balloon increases, the air pressure inside does not increase or decrease blindly."

"It tends to decrease first and then increase, which is called extreme point instability."

"When the air pressure decreases, it will be more difficult for us to blow up the balloon."

"When it exceeds the extreme point and becomes a 'big balloon', the internal pressure increases, and it will naturally be much easier to blow up. The internal pressure is strong, and the 'pressure' applied to the rubber will be greater."

Due to the blocking of the bandage.

Therefore, everyone at the scene did not realize that when Xu Yun said these words, his expression was not very confident.

no way.

Let alone the neo-Hookean model these days, even the Varga model has not yet been released.

Without model derivation, Xu Yun's famous radius ratio of 1.4 cannot be proved.

Therefore, he could only find another way to prove it from the angle of three-parameter degrees of freedom.

There's nothing wrong with the numbers anyway.

And just after Xu Yun finished explaining.

The entire study group was silent for a moment, and then there was a burst of applause.

clap clap -

The expressions of everyone were not excited, but most of the doubts in their eyes dissipated.

Instead, it is goodwill and recognition.

It's just like.

Xu Yun changed from a sacrificial offering to a church member?

See this situation.

Xu Yun couldn't help but heaved a sigh of relief in his heart.

Fortunately, the first level was finally passed smoothly.

Mentioned earlier.

After meeting Zhou Shaoping, Xu Yun came up with the idea of ​​forming an interest group.

It's just that Xu Yun's original plan was to figure it out slowly, and then do these things after he has established a firm foothold in the base.

Unexpectedly, by chance, Zheng Tao and the others wanted to worship him as a teacher, and Xu Yun could only take a step back, which forced the interest group to come out in advance.

But whether active or passive, one thing remains the same:

That is, Xu Yun is going to use the abilities of these youthful bosses to do something.

At the same time, he also wanted to see if he could export some knowledge of future generations, and try to make it easier for the Chinese physics community in this timeline.

After all, according to the normal development.

The Chinese physics community will face pressure from Europe and the United States for the next 60 years, and it was not relieved until the advent of the lone point particle.

Whether it is selfishness or justice, there is a prerequisite task that must be resolved:

That is to obtain the identity of this small group.

Of course.

Still repeated that sentence countless times.

The "recognition" that Xu Yun needs is not to be a younger brother, and he is not qualified to let these meritorious people call him his big brother.

The recognition he needs is more of a peer-to-peer acceptance, similar to that of friends of the same age.

But according to the current situation

This pre-task should be regarded as a preliminary solution.

At least

These bigwigs will not openly question their status as 'consultants'.

Then Xu Yun returned to the original position with the help of Qiao Caihong.

Zheng Tao stood up while the iron was hot, and asked everyone:

"Comrades, do you have any other opinions on Comrade Han Li's role as a study consultant?"

"."

Everyone at the scene was silent for a moment and shook their heads.

joke.

Everyone came to the interest group to learn knowledge, and now there is an obviously awesome boss in the group, who would be dissatisfied with such a thing?

To know.

Many of them were kings of papers when they were in school, but due to age and ability problems after arriving at the base, basically they have not formally joined the theoretical project teams involved in their majors.

For example, Zheng Tao and Zhou Shaoping decided to appoint them.

These two brothers are usually responsible for all kinds of physical work, such as the casting of Xu Yun's wheelchair, and various tasks of the construction sideline team.

So now there is such an interest group that can exchange knowledge, and there are consultants like Xu Yun in the group

It is not an exaggeration to say.

Some members already wanted to lie on Xu Yun's body and suck their brains. Ahem, to gain knowledge.

Then everyone chatted briefly.

Some are small phenomena encountered in work like balloons, such as the phenomenon of water hammer caused by the non-stop sizzling of water pipes.

Some exchanged the usual reading materials.

For example, "Hunter's Girl", "Red Flag Canal", "Fire King Kong", "Flower Shadows Beyond the Curtain" and so on.

During the period, Xu Yun occasionally interjected a few words, but most of the time he chose to listen in.

After all, this kind of discussion is like LOL in the later period.

Carrying alone is actually very boring. At most, after 1V5, someone sends you a few question marks to express your shock, and then there is a dull emptiness.

But Happy Wuhei is different. That is the real happiness, which is much more interesting than frying fish alone or even going on a blind date.

that's all.

Two hours later.

The first group event of the 'Never Update' interest group has come to a successful conclusion.

The group members parted ways, and many of them still had work to do in the afternoon.

Qiao Caihong pushed Xu Yun's wheelchair, preparing to go back to the hospital to continue today's treatment.

As a result, the two didn't go far.

A familiar greeting came from behind Xu Yun:

"Comrade Han Li, stop!"

Qiao Caihong hurriedly stopped.

Xu Yun then turned his head and looked at the speaker.

Only at this moment.

Ye Duzheng, who had not seen him for several days, was standing ten meters away from them with a man whom Xu Yun could not recognize, smiling and waving at them:

"Comrade Han Li, is it convenient for us to chat a few words?"