Chapter 181: Movie Success Semiconductor development

When Zhang Zhimu, Lu Bingyi, and Li Yunhe came to Qingfengzi's laboratory, there were many people who saw him here, and Zhang Bingchen was here. Zhang Zhimu guessed a few points in his heart, Zhang Bingchen and they were busy planting cow beans all over Shanxi, and it was likely that they came here because of their sulfonamide drugs.

Seeing that everyone had arrived, after being polite, Qingfengzi said to the disciples, "Let's start!" ”

Qingfengzi's disciples immediately closed the curtains on the windows, and only electric lights were lit in the room. One of Qingfengzi's disciples lifted the cloth covering a tripod. A wooden box was revealed. This wooden box is much larger than the original camera. When this disciple put the two discs on top of this wooden box, Zhang Zhimu was shocked, could it be that Qingfengzi and they made a movie so quickly?

A few of Qingfengzi's disciples were busy for a while, and then turned off the lights in the house.

Li Yunhe didn't know what was going on, "Hey! What is this black light for? ”

No one answered, but someone snickered in the darkness.

Suddenly, a bright light shot out of the wooden box, and a white light shone on the opposite wall. At this time, there is a sound of the motor turning and the gears turning from the inside of the box. The white light on the wall in front of me immediately became an image of the school playground, and the image of one student walked through the frame, and the next few students walked by.

At this time, there was no need to look, Zhang Zhimu knew that Li Yunhe and Lu Bingyi were so shocked that they couldn't close their mouths. There are people in the picture who are active, and it is unacceptable for them to accept it at once. But it's a pity that the picture obviously can't reach twenty-four frames per second, and the animation effect is obvious, which is estimated to be more than a dozen frames per second, and the focal length of the picture is not well adjusted, and the characters are a little virtual.

The movie was over after less than three minutes of screening. Qingfengzi's disciples opened the curtains. The room was sunny again.

After their eyes got used to it, they began to talk about it.

"Master Qingfengzi, how did you make this moving figure?" Lu Bingyi couldn't help but ask.

After Qingfengzi made some explanations, he asked Zhang Zhimu: "Mr. Zhang, how do you feel about today's movie?" ”

"It's a huge breakthrough!" Zhang Zhimu first affirmed their achievements, and said: "However, your current movies obviously do not reach 24 frames per second, the animation effect is obvious, and the movement of the characters is not natural enough. Also, when you were shooting, the focal length was not right, and the characters looked a little empty. ”

Mr. Zhang saw it at once. We're only able to get to sixteen frames per second now, and if we get any faster, the film exposure won't be enough. Qingfengzi said: "The focal length of that photography is not very good, and I didn't pay attention to this at the time." ”

"You've added the pigments, and the film has overcome the problem of overexposure of blue light and underexposure of other lights. You can also improve the exposure sensitivity of the film. For a film to be practical, it must reach twenty-four frames per second. If you solve this problem, I will ask Yangchang to combine the recording technology with your film, and then we will be able to see movies with sound and film. Zhang Zhimu said: "You have completed the very complicated work of photography, printing, and screening today, which is a major breakthrough, and I want to congratulate you." From now on, it's a matter of improvement. I can tell you that film will be a very big industry in the future. As long as you reach the level of practical technology, this industry will soon be like a train, shocking the world. ”

Zhang Zhimu's words made all the participants in the development of the film very excited, and their efforts were affirmed by Zhang Zhimu, which is a very proud thing. Listening to Zhang Zhimu's description of the prospect of this thing, how could they not be excited.

Lu Bingyi was also excited, he said: "I'm going to talk about the movie in Science magazine. Can Master Qingfuzi write an article about the introduction? ”

"No problem, I'll arrange for someone to write this article." Of course, Kiyofuko was glad to hear that she was able to present her results in the new issue of Science magazine.

Zhang Zhimu said: "This movie should be watched by students in turn, so that they can also broaden their horizons and use their brains." ”

"Okay, I'm asking them to make a little bit of film, and a little bit more content for everyone to see." Qingfengzi said: "Please ask Mr. Zhang to come over today, there is good news." Our sulfonamides have already been figured out. No, Zhang Bingchen is also here, they have already given some food to the rats, pigs, dogs and rabbits, and they didn't find anything serious. The next step is to test people. What should I do if Mr. Zhang needs to take a look at this matter? ”

"The successful development of sulfonamides is a great thing for all of us." Zhang Zhimu was a little excited when he heard this, "It's a pity that I'm allergic to sulfonamides." Otherwise I would have taken the lead in being the first to take this drug. ”

"I don't think it's as good as this, if there are patients in our hospital and they can't be saved, they can try this drug." Lu Bingyi suggested.

Zhang Bingchen said: "That's what we mean, but this matter is too big, and human lives are at stake." We still want to hear Mr. Zhang's opinion. ”

"I agree to give this medicine to those who are critically ill. But it is important to obtain the consent of the patient's family, and if the patient is conscious, to obtain the patient's consent. Zhang Zhimu said: "The problem with this matter is that the patients may have allergies, they are already critically ill, and if allergies occur, it is a risk to them." However, this drug is generally not life-threatening for normal people, and allergies are generally not life-threatening. Taking the dosage of this drug, we are going to try to come. And drink plenty of water, as this medicine can easily cause stones. It can also be taken with Souda Tin. ”

"Before the experiment, you must explain things clearly to the patient, and then sign the pledge." Lu Bingyi said.

"We can also agree to some patients' conditions. For example, if you participate in our drug trials, we can waive all the costs of their treatment and so on. Zhang Zhimu said.

"If Mr. Zhang says that, we will know what to do." Zhang Bingchen said.

"Master Qingfengzi, sulfonamide has been developed to save countless people, it is really immeasurable!" Zhang Zhimu said: "Almost most of the infected patients can be treated. In the past, it was possible to perform surgeries that were too afraid to be done due to fear of infection. ”

"Let's experiment as soon as possible. After the test, we hurried to speed up production. Qingfengzi's excitement was beyond words.

"Master Qingfengzi, are you done with your business?" Zhang Zhimu asked.

"It's over, let's talk about your business."

"Well, we are going to build a large paper mill right away, but the paper mill has to discharge a lot of polluted wastewater containing chemicals. If this wastewater is discharged directly into the river, the river will quickly become polluted. In less than two years, our Xiaoling River and Fen River will become a backwater river. Therefore, we want to build a paper mill at the same time, build a supporting sewage treatment plant, and the sewage treatment will be completed, and it will not cause too much pollution and then discharge. This is something that needs to be done with you. Also, Mr. Lu and the others are already building a domestic sewage treatment plant, let's see if we can solve this problem together. ”

"In this matter, we sent two people to participate in the design of your production line, and we will know what is contained in the sewage you produce. We just find a way to separate or precipitate it from the sewage and release the unpolluted water. However, I think that the pollution treatment of the paper mill and the sewage plant outside should be separated, and their pollutants are different, so there is no way to deal with them together. Qingfengzi said.

This matter is settled.

Qingfengzi asked Zhang Zhimu: "Mr. Zhang, do you remember what you said?" ”

Zhang Zhimu knew that what Qing Fengzi was talking about was that he had promised to teach them a course on semiconductors before, but because he was worried about Chen Yufeng's departure from the customs to fight, his heart had not been quiet, and he didn't have the heart to give a lecture, so he delayed it. Zhang Zhimu said: "Master Qingfengzi is talking about lecturing. A while ago, I was thinking about the front line and delayed. The day after tomorrow, we'll arrange it and start the lecture. It's also a top priority. ”

Qingfengzi said: "I have mobilized a lot of people, and they are all ready to listen to the class." ”

"Okay, it's settled." Zhang Zhimu said to Zhang Bingchen: "There can be many variants of sulfonamides, and the effects are also different. After the trial of this drug, you will continue to develop new drugs. But penicillin must not be put down. ”

Zhang Bingchen said: "Okay, Mr. Zhang. By working on sulfonamides, we have also broadened our minds. I think it's good for us to get penicillin. ”

was ready, and he was going to give a lecture to Qingfengzi and them, so that Zhang Zhimu's happy event was delayed for another two days. Yang Yulin gave birth.

However, Yang Yulin, who has always been arrogant, was very dissatisfied this time because she gave birth to a daughter. For this, Yang Yulin cried several times, and kept blaming herself for not being capable. Zhang Zhimu had to patiently tell her what is the reason why the combination of X and Y chromosomes determines the birth of a boy and a girl, but no matter how good the reason is, it changes the reality of having a daughter. Zhang Zhimu had no choice but to talk about the benefits of having a daughter. But this can only make Yang Yulin feel relieved for a while. There was no way, Zhang Zhimu had no choice but to say to Yang Yulin: "If you really want a son, we will create another one." ”

Zhang Zhimu thought to himself, there is no family planning index now, and he can afford to raise it.

Yang Yulin laughed when she heard this: "Really? ”

"Really, we'll start when you're better." Yang Yulin was embarrassed.

"What if it's still a daughter?" Yang Yulin lost confidence.

"If you're still willing, we'll continue." Zhang Zhimu said.

This time, Yang Yulin couldn't stop laughing, "As soon as you say something, it's different." Hehe! ”

After accompanying Yang Yulin for two days, Zhang Zhimu arranged for Qingfengzi to give a lecture.

First of all, Zhang Zhimu said:

"Today, the people who come to attend the lecture are the technical elites of our kiln, most of whom have listened to our mathematics, physics, and chemistry courses, and many of them have participated in the development of electron tubes and other materials. Today, we are going to open up a new field that we have not been exposed to before, and that is semiconductor technology.

The substances in our world are divided into conductors according to their ability to conduct electricity, which is easy to conduct electricity; There are insulators, which are very difficult to conduct electricity; There are also substances whose conductivity is between conductors and insulators, which we call semiconductors.

Semiconductors generally have a property, and that is a negative temperature coefficient. That is, when the temperature rises, the resistance decreases.

There are many semiconductor materials, which can be divided into two categories: elemental semiconductors and compound semiconductors according to their chemical composition. Germanium and silicon are the most commonly used elemental semiconductors, while gallium arsenide, gallium phosphide, cadmium sulfide, zinc sulfide, etc., are all semiconductors.

We refer to semiconductors that are free of impurities and have no lattice defects as intrinsic semiconductors. ”

Zhang Zhimu knows that talking about these things is really boring, but these foundations must be explained patiently and slowly. Then Zhang Zhimu introduced to everyone:

The atoms in a crystal form a neatly arranged lattice of dots in space, called a lattice.

A pair of outermost electrons (i.e., valence electrons) of two adjacent atoms not only move around the nucleus to which they belong, but also appear in the orbits to which the adjacent atoms belong, becoming a shared electron and forming a covalent bond.

At room temperature, a small number of valence electrons gain enough energy due to thermal motion to break free from the covalent bond and become free electrons.

The valence electrons break free from the covalent bond and become free electrons, leaving a vacant position called a hole.

Under the action of an applied electric field, the free electrons produce directional movement and form an electron current.

The valence electrons sequentially fill the holes in a certain direction (i.e., the holes also produce directional movement), forming a hole current.

Electron current + hole current. Free electrons and holes have different polarities of charge and they move in opposite directions.

The particles that carry the charge are called carriers.

There is only one type of carrier in which a conductor conducts electricity, i.e., free electrons conduct electricity.

Intrinsic semiconductors have two types of carriers i.e., free electrons and holes are both involved in conducting electricity.

The phenomenon of free electrons and holes produced by semiconductors under thermal excitation is called intrinsic excitation.

On the basis of this knowledge, Zhang Zhimu introduced the key things to everyone: P-type semiconductors, N-type semiconductors and PN junctions.

Through the diffusion process, a small amount of suitable impurity elements are mixed into the intrinsic semiconductor to obtain the impurity semiconductor.

P-type semiconductors are formed by adding trivalent elements, such as boron, to pure silicon crystals to replace the positions of silicon atoms in the crystal lattice.

Pure silicon crystals are mixed with pentavalent elements, such as phosphorus, to replace the position of silicon atoms in the crystal lattice to form N-type semiconductors.

In N-type semiconductors, many are free electrons and few are holes.

In P-type semiconductors, few sons are free electrons, and many are holes.

P-type semiconductors and N-type semiconductors are made on the same silicon wafer, and in the absence of external electric field and other excitation, the number of many particles participating in the diffusion motion is equal to the number of few particles participating in the drift movement, so as to achieve dynamic equilibrium, and a PN junction is formed at their interface.

PN junctions are unidirectionally conductive.

After the basics were introduced, it took a few days. During this period, Zhang Zhimu discussed issues with everyone more. Zhang Zhimu obviously felt that although Qingfengzi and they were very hard, it was still very difficult to understand these things. Because it is difficult for their thinking to enter the state, Zhang Zhimu feels that the only way to let them slowly understand when they do it concretely.

Zhang Zhimu began to teach them how to make monocrystalline silicon. In fact, Zhang Zhimu himself has never seen the production of monocrystalline silicon, but has only watched some science and education films. At that time, I didn't think that I would make monocrystalline silicon, so I just looked at it. At present, it is still very difficult to reconnect the various process problems. However, I can still point them out some directions, so let them do it themselves.

At this point in the class, Zhang Zhimu said to everyone: "I think many people who have listened to my class have had this experience, and when it comes to these basic things, everyone has a difficult period. Because what I said has never been exposed to before, knowledge is new, and it is right for everyone to have a process of understanding. What I'm going to talk about again is the question of how to do it. After you have done it, you will have a deeper understanding when you go back and understand what we have just learned. This is also the law of understanding, we need to practice understanding, and then practice and then understand. ”

Then, Zhang Zhimu told everyone about the production process of monocrystalline silicon.

First of all, the quartz sand is cleaned and then reduced to silicon with carbon in an electric arc furnace. The purity of the silicon thus reduced is about 98-99%. Such silicon cannot be used to make semiconductors, and crude silicon (Si) must be converted into silicon tetrachloride: Si + Cl2 → SiCl4. After SiCl4 is purified by rectification, SiCl4 is reduced with pure zinc or magnesium to obtain higher elemental silicon:

SiCl4 + 2Z

→ Si + 2Z

Cl2

Finally, the physical method - regional melting method - is used to further purify the high-purity monocrystalline silicon.

The regional melting method is a method of refining single crystals from a melt. First, the raw material powder is fused and pre-made into a sintered rod or material rod; It is then slowly passed through a region with a temperature higher than the melting point of the material, causing it to melt and recrystallize into a single crystal. This process is characterized by the fact that only one part or one end of the rod is in a molten state at any given time, and the single crystal growth is completed by moving the heating coil or moving the rod to advance the molten zone to the other part or end. With the help of repeated remelting and recrystallization, the composition of the crystal can be guaranteed to be pure, free of gas and solid inclusions, and the structure is perfect and defect-free.

Because monocrystalline silicon is hard and brittle, the cutting is all wire saw with silicon carbide sand cutting.

After cutting, it also needs to be polished before processes such as penetration can be considered.

Zhang Zhimu knows that now that Qingfengzi and they can do this, it will not be far from making PN knots. But if you don't get to this point, there's no point in going on. Zhang Zhimu said: "Regarding semiconductors, I can only talk about it here. After you have produced monocrystalline silicon, I will tell you how to make PN junctions and diodes and transistors. ”

Zhang Zhimu looked up at everyone, and said: "We have two very complicated things in Yaogang now, one is that Li Yunhe and they organized people to prepare to build cars, that is, cars driven by gasoline and diesel, and after having cars, there is no need for horses to pull carts. In the future, each of us will be able to drive a car around the world by ourselves. The other thing you do is your semiconductors. Presumably, when I talked about PN junctions, some people who have worked on digital circuits and wireless circuits have already thought that the gate circuits made of diodes made of PN junctions will be much simpler and smaller than electronic diodes, and they will be more power-efficient. Replacing the detector diode in the radio with a semiconductor diode would also be much easier. It would be more convenient to replace the rectifier with them. In fact, in the future, there will be triodes and integrated circuits, which will have a more profound impact on our way of life and work. What I want to say is, let's do it! A better future awaits you. ”

Zhang Zhimu's words were both rigorous and emotional, which made these people who participated in the study feel both stressed and excited.

The pressure is that they understand that they are going to have a lot of problems that they have never encountered before, and they need to solve them step by step. What is exciting is that Zhang Zhimu pointed out the future for them that they yearn for very much. Although they can't know what that future will be like, it will definitely be unimaginably beautiful. Just like many of them, when they first came into contact with the tube, they never imagined that there would be a radio station today. Radio stations are now closely related to everyone's lives. Therefore, they believe that the better future that Zhang Zhimu said will be very beautiful.

Zhang Zhimu gave a lecture to Qingfengzi and them during this time, and it took him a week to tell Yang Qinglian that as long as the sky did not fall, he was not allowed to disturb his lecture. Yang Qinglian really did it and didn't bother Zhang Zhimu. But this week, a lot of things have happened.

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The Song army occupied Hokkaido, and Yuankou landed on the island of Kyushu. Opening up the Japanese battlefield. --Progress of "Memories of the Southern Song Dynasty".