Siheyuan: I eat melons while doing scientific research

Chapter 1241 How to confirm? (4k)

"We tore it off several times below 50nm, and the substrate comparison test showed that it can be peeled off again many times." When saying this, the comrades in the Technical Department of the Third Factory were excited and unbelievable.

Well, it seems that comrades are quite good at tearing off the tape, and the highly oriented pyrolytic graphite of Northeast Carbon Research Institute also meets the requirements.

Gao Zhendong said: "Then what do you think this means?"

"Chief Engineer Gao, does this mean that there may be a graphite crystal that exists in a two-dimensional form, or a nearly two-dimensional form? The experimental plan you designed is very targeted and is definitely not aimless. Have you anticipated that this might happen?"

The comrades in the Technical Department of the Third Factory have been wondering what Gao Zhendong's irrational experiment was for. It seems to be useless, and the experimental method is not high-end at all, it looks like a joke.

It is to use tape to stick the highly oriented pyrolytic graphite, then tear it apart, over and over again.

This description is not a simple description of the principle, but it is the actual operation, which makes people feel uncomfortable.

Although the comrades in the Technical Department of the Third Factory had some grumbles in their hearts, they still observed discipline. Their task was to tear off the tape according to the requirements of Chief Engineer Gao.

Looking at the experimental results now, comrades know that Chief Engineer Gao had already anticipated this. If not 100%, then at least he had some estimate.

This inference made the comrades gasp. As a professional technical unit in metallurgy and materials, the Technical Department of the Third Factory may not know much about other things, but it is very familiar with the knowledge of crystal structure. Otherwise, Gao Zhendong would not have asked the comrades of the Technical Department of the Third Factory to handle this matter, but would have chosen more suitable units and personnel.

In the opinion of these experts, this kind of material is impossible to exist in current theory! But the facts now show that this theory may have a little problem.

It seems that we have seen the dawn of overthrowing the conclusions of classical theories. Everyone knows how significant this is.

Even if this theoretical conclusion is overturned, it may be difficult to find any specific application direction for the time being, but this matter itself is of great significance.

Several comrades from the Third Factory were very excited. Although their role in it was probably just physical labor, being able to participate in such things was enough to make people excited.

But dawn is dawn, and in science, something can be used without proof, but if you want to prove it, you need a complete chain of evidence and logic.

It's just a suspicion now, but there's no proof.

All the comrades turned their eyes to Gao Zhendong. Since Chief Engineer Gao initiated this research, he must have follow-up measures!
Looking at his comrades' eyes, Gao Zhendong nodded and smiled: "Well, it seems that the comrades have guessed the purpose of my project. Then the next step is to prove that the thing torn out of the tape is indeed a two-dimensional material."

Proving that the two-dimensional material in hand is a two-dimensional material sounds a bit like having a household registration book and ID card but needing to prove that your father is your father, but there is a big difference between the two.

Gao Zhendong's next words did not disappoint the comrades who were eagerly waiting: "We now have several ways to study and verify this matter..."

Several methods? It is indeed Chief Engineer Gao’s style!
"The first method is actually more traditional in principle. Of course, the effectiveness of the proof is slightly weaker. To some extent, it is an indirect proof, but it is also useful under the current conditions. Comrades, have you ever encountered an intellectual problem, how to measure the approximate weight of a grain of rice?"

Gao Zhendong's words were like a bolt of lightning, instantly splitting the fog in the comrades' heads.

This method is just like tearing off tape by hand, it is really rustic, but it is really effective.

The theoretical value of the diameter of a carbon atom in this era is about 0.22nm. When the electron cloud fluctuations are superimposed, although it is not yet clear how much impact the electron cloud fluctuations have on the observed diameter of the carbon atom, it is clear that this will increase the observed diameter of the carbon atom, and the order of magnitude is basically clear, that is, when the carbon atom is superimposed with the electron cloud fluctuations, the observed diameter of the carbon atom is about 0.4nm.

With these theoretical foundations, plus Gao Zhendong's tip about weighing a grain of rice, comrades will no longer be blindly concerned about this.

"Chief Engineer Gao, is your idea to stack multiple layers of samples and then measure their total thickness? And finally use division to get the average thickness?"

"Yes, that's my idea, but it's more indirect. Considering the diameter and compression characteristics of carbon atoms, and the 50nm resolution of the scanning electron microscope we have, we only need to determine that a piece of highly oriented pyrolytic graphite has 200 layers, and then measure its thickness. As long as it can be determined to be between 50nm and 100nm, it proves that the single layer thickness of the highly oriented pyrolytic graphite crystal does not exceed 0.5nm!"

A resolution of 50nm does not mean that all thicknesses between 50nm and 100nm can be measured, but that 50nm is a level and 100nm is a level. Therefore, Gao Zhendong, who is very clear about the thickness of graphene being 0.34nm, chose the number of 200 layers.

After all, if there are 100 layers, it exceeds the lower limit of resolution, which is difficult to explain.

The comrades are full of energy. This is Chief Engineer Gao. His ability to simplify things is truly amazing!
However, some comrades did not change their minds: "Chief Engineer Gao, what if the thickness of these materials is uneven?"

Before Gao Zhendong could answer, another comrade interrupted him: "Are you stupid? If the material thickness is not uniform, this discovery would be even more amazing! According to the drawer principle, if the 200 layers of material with a total thickness of less than 100nm are not uniform, then it proves that at least one layer of material has a thickness of less than 0.5nm!"

Drawer principle: if there are 5 drawers containing 6 balls, there must be at least one drawer with more than or equal to two balls. This is a very commonly used mathematical principle.

Gao Zhendong nodded: "Yes, that's right. So comrades can do this."

"But Chief Engineer Gao, we have no way to count how many layers there are in a piece of graphite that is tens of nanometers thick." Such a thin thickness is a bit difficult for the comrades. In their opinion, if they can count the number of layers clearly, it means they can see clearly how thick a layer is.

Gao Zhendong shook his head and smiled, "That's not necessarily true. If you want to know how many layers there are, you don't necessarily need to know how thick a layer is. Look at how many pens I have in my hand, and you should know that, right? But do you know how thick each pen is? It's the same principle."

"Chief Engineer Gao, are you saying that we can use other means to determine the number of layers, but not care about how thick it is?"

"Yes, for example, we can use a Raman spectrometer to count the number of layers. You can simply think of it as a Raman spectrometer that has a characteristic signal for each layer. By counting the number of characteristic signals, we can verify how many layers it has. Moreover, today's Raman spectrometers use lasers as light sources, which have better performance and can be used here."

Others were not stupid either. After Gao Zhendong invented the laser, the traditional equipment, Raman spectrometer, was reborn.

Gao Zhendong didn't have to work on it himself, as foreign friends naturally made it. This is one of the reasons why Gao Zhendong announced the laser generator as soon as possible, in addition to the fact that others were also about to make it. - We can use the power of others for our own benefit. Our accumulation is not as good as their accumulation over the years. As long as others have made it, even if they don't tell you the twists and turns inside, as long as we can use it, it's fine, especially in the field of measuring instruments.

As someone who works on materials, I am no stranger to Raman spectrometers.

"I see, but Mr. Gao, even if we know the number of layers, we can't prove that we have peeled off a layer as thick as a single atom, right?"

As long as the thickness is not measured, there is no way to confidently say that you have obtained a single atomic layer crystal.

Another comrade said: "Theoretically, the number of times we can tear a single atomic layer below 50nm is also limited. Can't we use the number as evidence?"

"No, people can say you were torn into two halves, not into two layers," said the comrade.

Tearing a 16A paper into two 32A sheets and tearing it into two thinner 16A sheets are two completely different things.

Gao Zhendong smiled and nodded: "Yes, what you said makes sense, so we still need to confirm the result of our tearing, which is indeed about 0.4nm thick. Have you forgotten that one of the electron microscopes we imported is a transmission electron microscope?"

In the 60s, the transmission electron microscope (TEM) was able to achieve imaging with a resolution of 0.2nm. In fact, there are other methods, but the equipment does not support them, such as atomic force microscopes, cryo-electron microscopes, etc. These things did not exist at that time.

However, this thing is very troublesome to use, and the sample preparation has a high threshold requirement. Comrades have basically not used it. After all, no one would have thought that an experiment of tearing off tape would require such a high-precision microscope. They have just obtained the microscope, and they have all tried their best on the easier-to-use scanning electron microscope.

After hearing what Gao Zhendong said, the comrades looked embarrassed: "We are having some problems using TEM now..."

Gao Zhendong shook his head: "It doesn't matter if there are problems. You can learn it. If it doesn't work, we can ask for external help."

For Gao Zhendong, asking for external assistance is not a problem at all, after all, he has the support of the Institute of Science and Technology. If this matter is put forward, there will definitely be many comrades in the Institute of Science and Technology who are interested.

When the comrades from the Third Factory heard that Gao Zhendong was going to ask for external help, they were unwilling to admit defeat: "Chief Engineer Gao, let us give it a try. We don't believe that we can't do this TEM well! Of course, if it affects the progress of your plan, we will give way to you."

After all, no one knows whether Gao Zhendong's research has any time requirements. If he only cares about his own people's efforts and affects Chief Engineer Gao's progress, it would be a big sin.

After hearing what they said, Gao Zhendong shook his head: "It doesn't matter, you guys try your best, this matter is not urgent."

If it weren't for Gao Zhendong, this idiot, wanting to come up with this thing, it would have to be the 21st century.

Hearing Gao Zhendong's words, the comrades were moved and excited. With such a leader, what more could they ask for? They knew very well that the time they spent on learning TEM would definitely affect Chief Engineer Gao's progress, but Gao Zhendong had full trust in them and gave them enough time, of course, on the premise that they were willing to take on this challenge.

"Chief Engineer Gao, don't worry, we will do this well! We don't believe that if we make a sample according to the specific requirements, we will get nothing!" The comrades in the Technical Department of the Third Factory were ready to go and rushed forward with a roar.
-
Southwest, Sichuan Province, Shuangqing City.

This city, famous for its hot girls, actually has a more special identity, that is, the birthplace of the originator of domestically produced off-road vehicles.

Hot knowledge - The originator of domestic off-road vehicles is not Erdan, but it is indeed the first one that is truly independently developed.

1958年，这里诞生了第一辆国产越野车——仿制花旗威利斯M38A1（CJ-5）的龙江46型。

However, due to limited technical capabilities at the time, the reliability of this car was not very good. It was eventually replaced by Erdan of Beijing Automobile Works. This replacement took place before Erdan was finalized. Instead, the production was stopped in 1963 when Erdan's entire car was basically finalized, with a total output of 1390 vehicles.

The fact that it was replaced so quickly shows that the foundation of Longjiang 46 was indeed not very good. And the fact that such a simple car as Willys M38A1 had poor reliability also shows that the technology was indeed weak at that time.

The suspension of Longjiang 46 production was a big blow to the manufacturer, but they also knew that it was impossible not to stop production. Would they let the troops and local comrades continue to use this unreliable vehicle? That would be a crime!

They have learned from the new off-road vehicles and found that both the 2.0 and 1.5 models far exceed their own Longjiang 46 in terms of reliability, power, comfort, etc.

At this time, a comrade from Shuangqing Jiuan Machinery Factory was answering a phone call.

"...Really? That's great! Yes, yes, yes, we understand. I will organize people to go to Beijing immediately!"

After hanging up the phone, he immediately ran out and turned into another office next door.

"Chief Engineer Wu, Chief Engineer Wu, good news, good news! Please tell your deputy about the work immediately, and we will go to Beijing right away!" He danced with joy, very excited.

This made Chief Engineer Wu in the office confused: "Director Ou, what are you doing? What's so urgent? And you want both of us to go?"

You have to know that the top managers and technical executives are gone, so if something big happens, there won’t be anyone to make the final decision.

"We both have to go, this is a good opportunity! We must strive for it. If we can get it, all our hard work in making cars in the past few years will not be in vain!" Director Ou continued to dance with excitement.

"What? Related to cars?" Speaking of this, Chief Engineer Wu was no longer sleepy.

"Yes! My old colleague from the 11th Ministry of Machinery called me and told me that Beijing is preparing to put a new type of car into production and develop a new type of car, but the factory that will undertake this task has not yet been selected!"

(End of this chapter)