"Junior, please stay." Just as Yu Hua was about to get up and leave, a voice suddenly came from behind.
Yu Hua turned around and felt that all the seniors in the class were looking at him with some confusion. He looked at the freshman who made the sound and asked, "Uh, what's wrong, senior?"
Although Yu Hua and these students are both freshmen, the other students are already in the second semester of their freshman year, and Yu Hua's student status is only in the first semester of his freshman year, so he can be called a senior.
"Junior Yu, I have nothing to do. I just want to ask you, how do you know so much about Lebesgue integrals? According to common sense... you should still be learning definite integrals now." This senior who wears glasses and has a scholarly temperament,
He asked Yu Hua with a look of embarrassment and a little embarrassment.
There was respect in his words.
There was no bullying with a gun or mindless provocation, but he was particularly respectful, because after this class alone, he and the other seniors all understood that this junior who had just arrived for two days had real abilities, knowledge and mathematics.
His achievements are no less than theirs.
It is true that the waves behind the Yangtze River push the waves ahead, and the young are better than the old. I didn't expect that this junior student would be so powerful and master the Lebesgue points one step ahead of them.
"Uh... I can't explain this question very well. Lebesgue integral is quite simple, and you can get started by mastering the rules." After hearing this, Yu Hua scratched his head and didn't know how to answer, so he casually explained his understanding of it.
The corner of the senior's mouth twitched slightly: "..."
What does it mean to be quite simple?
You think it's quite simple, but why is it like reading a bible when we learn it?
Co-authored: You are a smart person, but we are all idiots?
Suddenly, the atmosphere in the classroom became slightly weird.
"Sorry, I really think it's quite simple. If seniors want to learn more about Lebesgue integrals, they can refer to "Reconstructing Lebesgue integrals" that I previously published in the Journal of Tsinghua University. They can understand it in an all-round way. This way,
This lays the foundation for the study of the theory of functions of real variables and the theory of functions of complex variables." Sensing the changing atmosphere in the classroom, Yu Hua felt helpless and looked at the senior who asked him questions. In order to maintain a good relationship with his classmates, he decided to speak a little louder.
To be honest, I really didn't want to show off. This kind of low-level taste is meaningless in the window period of only more than a month before the full-scale war of resistance.
Is it possible to engage in academic research and weapons research while pretending to be cool with your classmates?
Obviously not.
Lebesgue integral is a brand-new mathematical knowledge born in the 1920s. For the mathematics level of this era, it is indeed regarded as advanced mathematical knowledge. Yu Hua's article on reconstructing Lebesgue integral reduces the understanding of this knowledge point.
The difficulty of understanding makes it easier for people to get started.
After all, the next stage is the extremely torturous real variable function and complex variable function. If the Lebesgue integral is not learned well, the foundation will not be solid. To learn the real variable function, you really have to learn it ten times before you can understand it.
"You published an article in the Tsinghua Journal?!" The senior student's face was confused, his eyes widened in disbelief.
The atmosphere in the classroom became different again. This time it was not just one person who was confused, but a group of people.
All the first-year students in the Department of Mathematics at National Tsinghua University looked at Yu Hua blankly.
Others don’t know the importance of Tsinghua Journal. As students of our school, don’t they understand?
This is the top academic journal in the country.
"Seniors, I have something to do, so I'll leave first." Yu Hua looked at everyone's reaction, sighed, and decided to give up the idea of explaining. No matter what he said at this time, they would think he was showing off.
After saying that, he pulled away and left.
After Yu Hua's figure disappeared, everyone in the classroom finally came to their senses and barely digested the shocking news revealed by Yu Hua.
"Nang Xipi, what is the origin of this junior fellow student? He actually published an article in our school's journal! This is our school's journal!"
"The key is that what they published is still mathematics articles!"
The atmosphere suddenly became lively. As the top academic journal in the country, our school's journal has very strict review of the quality and content of articles. The rejection rate is as shocking as the student elimination rate last year. The key point is that among the sixteen majors in the school, the difficulty level is
The highest one is the Department of Arithmetic.
Articles in the Department of Mathematics have always been famous for being esoteric and unfamiliar. Most people cannot understand the content of the articles and cannot understand the logical relationships and formulas. Those who can understand them can be regarded as extraordinary.
As for writing a mathematical article and publishing it in a journal...
Such a beautiful thing, as all the first-year students of the National Tsinghua University Department of Mathematics, these six people have never thought about it, right?!
"Edi Niang... our school's journal has published an article. I'll go check it out later. No, I have to go to Yangchun Garden at noon to treat my shock. My heart feels unbearable."
"Let's go together. It seems that a big shot has arrived in our Department of Mathematics."
"Including me, it has been twenty hours since I last went to Yang Chunyuan. I feel that I have lost contact with the world and urgently need to establish communication channels. Having said that, I am planning to change my major. Mathematics is really not something that humans can do.
I learned it, I thought I could learn mathematics, but in the end I learned nothing."
"Sigh... Who says it's not the case? As long as I don't grasp a little bit of knowledge, the things taught in the following courses will be completely useless. Also, Princeton's textbooks are too difficult to learn. I kind of want to transfer to the Department of Civil Engineering."
…
After lunch, he replenished his energy. Due to his status as a recommended student, there were not many courses arranged by the school during this period. Yu Hua went directly to the library to continue studying the first set of encryption algorithms.
If you want asymmetric cryptography to enter the practical stage, you must first have an encryption algorithm, and secondly, you must formulate an algorithm password table, that is, the corresponding numbers and text language after decryption.
Yu Hua uses two language systems: northern Mandarin and hometown dialect. This can improve confidentiality and versatility to a higher level.
This is a huge, time-consuming and labor-intensive project, and only Yu Hua, who has extremely terrifying computing power, can do it alone.
Under normal circumstances, if you want to build a set of encryption algorithms and algorithm password tables, you must use a team of ten coding experts and hundreds of related personnel, and it will take at least three months to complete.
"Huh... Encryption algorithms are here for the time being. Let's go to the mechanical hall." Two hours later, Yu Hua, who had exhausted his efficient study time for the day, had to choose to suspend his research work, packed up his personal belongings, got up and left, and went straight to
Mechanical Museum.
Yu Hua was still very interested in the homework assigned by Professor Zhuang Qianding, mainly because he could take this opportunity to use precious general lathes and gantry mills.
The general lathes and gantry mills belonging to the Department of Mechanical Engineering are placed in the Mechanical Hall and are exclusively used for teaching students of the Department of Mechanical Engineering. Of course, students like Yu Hua who take mechanical engineering courses can also use them as a matter of course.
You must know that the American-made imported general lathes and gantry mills of this era were heavy, extremely expensive and rare. The school specifically stipulated that non-mechanical engineering students and elective students were not allowed to use these two pieces of equipment.
As soon as he left the library, Yu Hua came to the door of the majestic mechanical library, which was made of brick-concrete structure. After the guard checked his student ID, he entered the library with a curious heart.
To be honest, this is his first time entering the mechanical hall.
The Department of Mechanical Engineering has set up three subject group laboratories in the library, which are divided into power engineering group, mechanical manufacturing engineering group, and aircraft and automobile engineering group. It is the mechanical manufacturing engineering group laboratory that Yu Hua is going to.
Following internal instructions, Yu Hua quickly arrived at the laboratory where the mechanical manufacturing engineering team was located, which was like a factory workshop. Looking around, the laboratory was bright and spacious, with two machines and equipment exuding industrial beauty placed in the middle. As soon as he arrived,
The sound of metal processing machinery and motors could be heard in my ears.
Professor Zhuang, wearing greasy gray overalls, stood in front of the truck and was controlling the equipment to process metal parts.
Yu Hua stepped forward, stood outside the safe area, and waited quietly without making a sound. With a learning attitude in his heart, he carefully looked at and observed Professor Zhuang's operation process.
Regarding machine tool manufacturing, Yu Hua is in a state of partial knowledge. He knows a little, but not a lot.
The three-jaw chuck installed on the main spindle of this ordinary car firmly clamps and fixes a disc-shaped silver metal rod that rotates at high speed. The turning tool feeds smoothly and contacts the processing material, cutting out strips of filaments or strips.
The metal comes out.
It can be seen that Professor Zhuang's operation is very subtle, and the amount of cutting and back cutting are not large.
"It seems that they are processing a rotor." Yu Hua carefully observed the shape of the parts on the three-jaw chuck, which looked like a rotor. The specific type of rotor was not clear. He looked at Professor Zhuang's concentration and did not disturb him.
He looked around and looked at the mechanical manufacturing engineering group laboratory. The gantry mill next to him was like a giant, much larger than the ordinary car in the same laboratory. The width of the gantry was visually estimated to be about two meters, and the length of the workbench was three meters.
It can mill and process workpieces of 2000 mm × 3000 mm.
This gantry milling machine could not be manufactured at all based on the level of machinery manufacturing in the Republic of China.
Although the performance and quality of American-made machine tools are not as good as German-made machine tools, they are much better than machine tools independently manufactured in the Republic of China.
Yu Hua looked away from the gantry mill. At this moment, the metal bars piled up not far away attracted his attention like gems. When he saw this, his eyes suddenly lit up.
Metal bars!
Yu Hua left his position and came to the pile of metal bars. There were about twenty metal bars in total. He squatted down and picked up one of them and looked at it carefully. It was about sixty centimeters in length and one centimeter in diameter. It was made of solid material.
The surface is smooth and clean, with no obvious defects such as cracks and bubbles.
This is a metal bar that has been forged and processed. It is of high quality and is very suitable for making the core parts of a machine...
barrel!
At this time, a gentle and familiar voice came from behind: "Be careful, these experimental materials are very expensive."
"Hello, Professor Zhuang, I'm sorry to cause you any trouble." Yu Hua quickly put down the metal bar, stood up, turned around and said hello to Zhuang Qianding.
"It's just the two of us here. Don't be restrained. Do you know what these experimental materials are?" The lathe not far away has stopped working. Zhuang Qianding, who was covered in dust and oil, smiled and pointed to the metal bars on the ground.
, asked Yu Hua.
Is this experimental material?
If this were left to future generations, if someone processed a gun barrel in a university, they would not be sentenced to three to five years.
Yu Hua glanced at the experimental materials on the ground, was silent for a second, and said bluntly: "If the student guessed correctly, these should be gun barrel blanks."
"I'm knowledgeable, but I didn't expect you to know the gun barrel blank material. Most people think that the gun barrel is made of seamless steel tubes. Little do they know that the real gun barrel is actually made of blank material. Small-caliber seamless
The effective life of a gun barrel made of seamed steel pipe is only tens or hundreds of rounds, which is one-tenth of the barrel blank material."
Zhuang Qianding was slightly surprised. He didn't expect Yu Hua to be so knowledgeable. He squatted down, picked up the gun barrel blanks that had been placed for a long time, and said with emotion: "These gun barrel blanks are high-quality alloy steel imported from the United States. They have been forged and anti-corrosion treated.
, high strength, high temperature resistance, and corrosion resistance. This high-quality alloy steel material has very good performance. It can process diameters below 8 mm, and the pipe wall thickness can reach 2 mm. It is a pity that our country is currently unable to smelt this kind of steel.
It is a high-quality alloy steel and does not have the processing technology. Yu Sheng, do you know how much each gun barrel blank costs?"
"I don't know." Yu Hua shook his head gently.
"Each stick is 15 US dollars, which is about 60 yuan, which is enough to cover my monthly salary." Zhuang Qianding shook his head and sighed.
When Yu Hua heard this, he was not surprised at all. The price of this kind of weapon-grade metal material is already expensive, especially the gun barrel blank. If it is the gun barrel blank, the price will increase by two orders of magnitude, reaching a hundred times.
.
The price of ordinary steel is one hundred and twenty oceans per ton, and the price of high-end metal materials such as gun barrel steel and gun steel easily exceeds ten thousand oceans per ton.
The key is, there is a price but no market.
Steel is a strategic material, and high-end steel is the most strictly controlled in the strategic material system.
"Sir, this price shouldn't be the current price, right?" Yu Hua asked.
"It seems that you know the gun barrel blanks very well. It is true. This is the blank material imported in December last year. The total quantity is twenty. This year, the price is estimated to have increased by at least double." Zhuang Qianding nodded.
, said.
Yu Hua shook his head, and then asked curiously: "The situation in Beiping has been tense recently and prices have risen. The students just guessed. By the way, Professor Zhuang, why didn't these blanks be processed into gun barrels?"
"It can't be processed. The school originally planned to use this opportunity to cultivate students' ability to process gun barrels. Last year, it planned to purchase a drilling machine and deep-hole gun drill from the Americans. However, before signing the contract, the other party suddenly opened its mouth and thought that after we purchased the drilling machine,
They will imitate them, increase the price by five times, and require the purchase of more than ten units at a time. All the money must be paid before the equipment is sent. In the end, the school has no choice but to give up purchasing drill machines and deep-hole gun drills.”
Professor Zhuang slowly gave the core reason, with a trace of helplessness in his tone: "So these twenty gun barrel blanks have been kept in the laboratory for half a year. However, these gun barrel blanks have been left naturally for more than half a year, and the internal
The stress is well relieved, and if it is processed into a gun barrel, the accuracy will be higher."
Subject to others.
If you don't have something you don't have, others will get stuck on you.
The barrel blank material is restricted, the processing technology is restricted, and the equipment for manufacturing the barrel is also restricted.
Drill presses and deep hole gun drills.
A piece of equipment and a tool are the core equipment for processing gun barrel blanks. Without these two things, the gun hole cannot be drilled.
"Professor Zhuang, the student has a suggestion." Yu Hua heard this, thoughtfully, and after thinking about it, he looked at the Zhuang Qian Ding in front of him.
Zhuang Qianding heard this and said, "You tell me."
"We use this lathe and gantry milling to make deep-hole gun drills, and then use the deep-hole gun drills to process these gun barrel blanks to make gun barrels." Yu Hua looked at Zhuang Qianding and expressed his original thoughts.
Today, he originally came to the Machinery Hall for a walk and a tour of the interior. Now that he happened to have this opportunity, he decided to cut it off.
"Using lathes and gantry mills to make deep-hole gun drills? How to solve the problem of drill bit materials? And to say the least, even if we have drill bits, we don't have a drilling machine." Zhuang Qianding was startled when he heard this, his eyebrows slightly wrinkled, and he was interested.
, and felt it was unrealistic.
The drill tool material is the same as the gun barrel blank. They are both high-end steel products. The output is very small, but they are generally not purchased.
"Professor Zhuang, this is the ready-made deep hole gun drilling material. As for the drilling machine... you put the gun drill on the chuck, and then place the blank on the tool holder and tailstock, and you can process the barrel." Yu Hua
He picked up a gun barrel blank with his right hand and revealed the 'operation' idea he had already conceived: "After the inner hole is processed, use a broach to process it and pull out the rifling."
The assignment that Yu Hua originally planned to submit was to first let the organization use an electric arc furnace to smelt two metal bars, process one into a gun barrel, and process the other into a deep hole drill. After turning and milling, the processed deep hole gun was then drilled and placed.
On the lathe chuck, the basic conditions for barrel processing can be met.
This idea is feasible. After all, in addition to being called an industrial mother machine, a lathe is also called a "bench drill".
The laboratory suddenly fell into silence. Zhuang Qianding was stunned for three seconds, and then showed an expression as if he had seen a ghost. He looked at Yu Hua in disbelief and was deeply shocked in his heart.
At this moment, time seemed to stand still.
At this moment, Zhuang Qianding almost didn't know what to say.
Shock, surprise, confusion.
"Yu Hua, where did you get this method?" After several breaths, Zhuang Qianding finally recovered from his daze, took a deep breath, stared at Yu Hua with his eyes bulging out, and his words revealed a hint of eagerness and enthusiasm.
Excited, he called him by his name.
"Back to Professor, it's what the students thought about. You assigned the homework before and the students were going to use this method to make a gun barrel. I didn't expect that they happened to meet it today." Yu Hua responded softly, neither fast nor slow.
"Wizard, really a wizard. Your processing method is very feasible. Yu Sheng, do you have classes in the afternoon?" Zhuang Qianding felt more and more surprised and delighted. He carefully verified the processing method given by Yu Hua in his mind and confirmed that it was feasible. He hurriedly
asked.
Yu Hua shook his head and said, "Students have no classes."
"Then let's process this batch of gun barrel blanks together. After success, I will apply to the school for a scholarship. In addition, if you pass my elective course, even if you hand in a blank paper, I will give you full marks. Let's show it to those Americans.
, even without them, we can process the gun barrel ourselves." Zhuang Qianding took a deep breath, with a solemn and dignified expression, and made a serious promise to Yu Hua. He recalled the scene of the negotiation when purchasing drilling machine equipment in his mind, and gritted his teeth.
"Uh...Okay, Professor Zhuang." When Yu Hua heard Professor Zhuang's promise, he was modest and reserved. He was originally ready to refuse, but the words stuck in his throat and he couldn't say it out.
Without him, Professor Zhuang has given me too much.
There are really too many.
This is a scholarship and full marks for elective courses. Which college student can refuse?
Just do what you say, no ambiguity.
In the mechanical manufacturing laboratory, Zhuang Qianding, a professor, immediately got busy and began to formulate detailed steps, while Yu Hua was in charge of minor tasks.
Although Yu Hua was unable to carry out high-intensity thinking activities and calculations, he had no problem assisting Zhuang Qianding in getting started.
In addition, since there is only so much time for efficient study every day, academic research will further shorten the time due to the increase in consumption. Now that an agreement has been signed on the plan to replace technology with equipment, Yu Hua has more or less free time that can be squeezed out.
Processing gun barrel blanks is, at a small level, a matter of trying to gain a breath, but at a large level, it is an exploration and creation of a new barrel processing technology.
Process and manufacture gun barrels without drilling machines and deep-hole gun drills!