Chapter 243 Mathematics should be oriented to the national economy

Author: Zhe Lei

Chapter 243 Mathematics should be oriented to the national economy

"The universe is vast, the particles are tiny, the speed of rockets, the ingenuity of chemical engineering, the earth's changes, the density of living things, the complexity of daily life, mathematics is used everywhere."

Swish, swish, in the technical seminar of Jiangnan Shipyard, Cheng Nuo did not rush to introduce himself, but first wrote the above sentence on the blackboard, put down the chalk, turned around and smiled at the people under the podium: "

Is there any comrade willing to stand up and read the above sentence aloud?"

The teachers under the podium looked at me and I looked at you, with doubts in their eyes. I really didn’t know what this new teacher wanted to express.

Fortunately, Cheng Nuo had anticipated all this. He got down from the podium and walked to the center of the classroom and said: "A gentleman avoids three things, that is, he avoids the pen of the scribe, the sharp edge of the warrior, and the tongue of the debater. I can do this for you."

Understood. Let me introduce myself first. My name is Cheng Nuo. I am a newly hired consultant at our Jiangnan Shipbuilding Institute and the main lecturer of this class. We will all be working together for a long time in the future."

After a pause, Cheng Nuo turned around and pointed at the line on the blackboard and said seriously: "Let's do this. Whoever stands up first takes the initiative, I will add 10 points to him. As for what this point is for, it's very difficult.

Simple.

It is an important part of comrades’ overall score in this class. The more points you score, the higher your overall score will be, and the better your personal evaluation will be.”

As soon as he finished speaking, Li Nan stood up from the bench.

"Teacher, let me do it..."

But he ignored it. He only sat on one end of the bench, and there were other comrades sitting on the other end.

He stood up suddenly, causing the bench's center of gravity to become unstable, and it tipped over instantly. His companion was immediately thrown to the ground.

"Ouch, damn..."

"I'm sorry, I just ignored you. Are you okay?"

Seeing that the situation was not good, Li Nan immediately reacted and wanted to help his companion, but Cheng Nuo was able to take the lead. While helping him, he joked: "It seems that Comrade Li Nan values ​​​​this situation very much, even though he was a little rash."

, but this proactive attitude is still worth learning from."

Li Nan scratched the back of his head in embarrassment and said with a hint of embarrassment: "There is no need to learn from me. It would be too draining on your own comrades."

Fortunately, nothing serious happened after the fall. I patted the dirt on my body and the atmosphere in the class was restored again.

But with such a small episode, the tension that had been in the air gradually dissipated.

Looking at the writing on the blackboard, Li Nan breathed a sigh of relief and read carefully:

"The universe is vast, the particles are tiny, the speed of rockets, the ingenuity of chemical engineering, the earth's changes, the density of living things, the complexity of daily life, mathematics is used everywhere."

As the last word fell, Cheng Nuo took the lead in applauding.

"Very good, the pronunciation is very accurate and the emotion is very strong. I'll give you ten points!" Cheng Nuo smiled and nodded, then looked at the "injured" comrade before and said: "But in view of Comrade Li Nan's ten points, I will give you ten points!"

The table has caused some minor troubles. In order to make up for it, I will give an extra 5 points to the tablemate. Do you have any objection?"

Li Nan shook his head repeatedly: "I have no objection. It was my mistake in the first place."

"Not bad." After getting a positive reply from Li Nan, Cheng Nuo looked at the others with a smile: "Do you have any opinions?"

"No~" Everyone said in unison, looking at the two of them with a hint of envy.

Just as Li Nan breathed a sigh of relief and was about to sit down with a little happiness in his heart, he was stopped by Cheng Nuo.

"Wait a minute, Comrade Li, I haven't finished saying this yet. Don't rush to sit down and talk about your understanding of this sentence. It's best to combine it with our shipbuilding scene." Cheng Nuo smiled and encouraged: "Yes.

Yes, this question is an additional question. If you answer it correctly, you will also get bonus points."

Li Nan's mind went blank for a moment, and he opened his mouth for a long time before hesitatingly said: "Calculating...calculating the length of the hull requires mathematics..."

"What's behind?" Cheng Nuo asked.

"I won't know about it later." Li Nan raised his head, not daring to look directly into his eyes.

Cheng Nuo was helpless and had to raise his hand to ask the other party to sit down.

However, there was a good start from the first move, and everyone in the back spoke enthusiastically, with various ideas:

"Statistics can be applied in ship positioning to help ship positioning technology accurately position and facilitate reliable movement of ships. By collecting ship position data at different time points, the ship's driving route can be inferred, and the subsequent driving route of the ship can be predicted to ensure the safe driving of the ship...

…”

"There is also geometry, which can be used to calculate and plot the shape of the hull, the dimensions of the ship, the curvature of the hull, etc."

"There are also the principles of trigonometry, by which the angles, distances and heights of a ship can be calculated and measured. For example, using trigonometry the height of a ship's hull can be measured to determine whether the hull meets the design requirements..."

It seemed that everyone was talking at once, but Cheng Nuo actually found that the answers were basically given by the Chinese workers he brought back from Europe, and most of the knowledge was the knowledge taught in the night school he founded.

The corridor in the middle of the classroom is like the border between Chu and Han, which separates the Jiangnan Shipyard and the Chinese workers in Europe.

While he became more and more confident as he spoke, he began to feel a little downcast.

Seeing the opponents constantly adding points, the workers of Jiangnan Shipyard, who originally regarded themselves as the masters, lost their original arrogance and began to feel a little unable to sit still.

The young man next to him looked left and right. The more he looked, the more panicked he became. He quickly pulled the old master who closed his eyes to rest.

"Master, we have to do something, otherwise we will be inferior to others in our factory from now on. How can this be justified?"

The master sat firmly on the Diaoyutai, slowly picked up the enamel cup, blew off the tea foam on the water, and after sucking for a while, he said: "Where are you now? Don't worry. Besides, when the foreigners were in control,

We haven't been taught anything technical, so how can we stand up and compete with others?"

After all, he is young. Even with the guidance of the master, the young man still can't sit still: "But master, you have said before that you can't just sit back and wait for death. Now we just watch others eat meat. This is not okay."

"That's enough!" The master's eyes widened, he covered the tea cup with one hand and slammed it on the table: "What's wrong, you don't listen to what I say? If you know everything, why do you need to sit here? If you want to fly high first,

Flap your wings, if you want to make progress, you should study first. If you only see the struggle of will and spirit, what great things can be accomplished? Just listen to what others say!"

As he spoke, the master took out a notebook and pen from his waist and spread them out on the table.

Seeing that the young man had not yet reacted, the master snorted coldly: "You will live and learn until you are old, and you still don't listen carefully? If you really want to gain a reputation, then study hard!"

With the master proofing, even if they were dissatisfied, the workers at Jiangnan Shipyard began to correct their attitude. No matter how provocative the Chinese workers in Europe were, they turned a deaf ear.

Cheng Nuo naturally saw everything that happened below and remembered it in his heart. Knowing that he could not go on like this, he clapped his hands and stopped answering.

"Everyone's answers are very good, but for our shipbuilding industry right now, although mathematics can be used in many places, everything has its own priority. Today we are going to learn mathematical lofting of the hull. So what is lofting? Please

Let us, the master with the most experience in shipbuilding here, give us the answer."

After saying this, Cheng Nuo took the initiative to applaud again and looked expectantly at the old master.

This time, the old master did not refuse. He put down the pen in his hand. Shi Shiran stood up, cupped his hands in all directions and said calmly: "Then I will give you some ideas. If there is anything wrong, you are welcome to correct me in time."

Nodding towards Cheng Nuo, the master said steadily: "The so-called setting out, its direct meaning is to enlarge the design drawing drawn at a certain scale on the drawing into a 1:1 full-scale drawing. Of course, it may also be 1:1.

:5, or even 1:10, to name a few.

In terms of shipbuilding, the purpose of lofting is to produce various parts of the hull, such as ship plates, keels, bottoms, etc. After lofting is completed, each cross-sectional curve of the hull will be transferred to the appropriate material, where it will be

Cut, riveted or welded to ultimately form the complete hull structure."

"Well said, the master is really a master, he hits the nail on the head!" Cheng Nuo walked up to the master in person, asked him to sit down and said: "Hull lofting is a crucial step in the shipbuilding process. It ensures the accuracy of the hull design.

Accuracy and consistency.

Through lofting, our hull designers can verify the curves and dimensions on the design drawings and translate them into actual construction instructions, making the hull construction work more accurate and efficient."

Walking back to the podium, Cheng Nuo directly erased the famous mathematical saying and drew a smooth curve: "If you put it in mathematics, it is easy to understand. It is used to convert the two-dimensional curve on the hull design drawing.

Into the three-dimensional shape of the actual hull..."

Generally speaking, stakeout has two main purposes. The first is to make a practical check of the original design and modify the unreasonable or wrong parts of the design.

The second is to provide sketches, sample rods, sample plates, and sample boxes as the basis for construction for each subsequent process of unloading, processing, assembling, launching, sprinkling, etc.

The work generally includes three parts: linear layout of the hull, structural layout and expansion of the outer plating.

Take the 10,000-ton giant ship that Cheng Nuo and the others are currently building as an example. The line drawing of the 10,000-ton ship is drawn at a scale of 1:100. If there is an error of 0.5 millimeters on the drawing, when enlarged to the actual size, the error will reach 50

mm.

In order to avoid mistakes in the process, Cheng Nuo specially selected some more practical mathematical principles and calculation methods, compiled them, and taught them to the comrades present to carry out manual mathematical lofting.

The derivative values ​​of the several-order functions at each endpoint of the spline curve used in mathematical lofting of the hull are the information of the spline curve, that is, the category of computational geometry.

Among them, the main theory of mathematical lofting comes from Mr. Su Buqing, the founder of the school of differential geometry in our country, known as "the brilliant mathematical star in the Eastern countries", "the first geometer in the East" and "the king of mathematics".

Su Buqing was no longer in his prime at that time, but he was still very concerned about practical production issues. He led his students to many factories, and later went to Jiangnan Shipyard to do mathematical stakeout of the hull, and to Shanghai Tool Factory to teach workers and technicians.

It solves the problems encountered in production for them and greatly improves the scientific and technological level and productivity of related industries.

Later, on the basis of the mathematical lofting project of the hull, Su Buqing, who was in his seventies, founded the new discipline of "computational geometry" and opened up a new field of geometric research. Later, the "Mathematical lofting of the hull" and other projects of the Department of Mathematics of Fudan University won the National Science Conference Award.

Although many of them require computer assistance and are not applicable to Cheng Nuo at this time, there are still some applied mathematics contents that greatly help Cheng Nuo and the others.

It was in this process of learning and discussion that the Chinese workers in Europe and the old employees of Jiangnan Shipyard gradually began to abandon their old grudges, and their relationship became more and more familiar. For example, Wang Tiechui pestered the master to ask questions, and

The master chef often consults with Wang Tiechui on new craftsmanship, and everything is developing in a good direction.

On the other side, Morgan, who "boasts himself in construction", simply dismissed it, picked up his cigar and took a puff:

"Jack, do you know where the cigars taste best?"

Jack quickly stepped forward and answered: "Of course, sir, the cigar in your hand tastes the best."
To be continued...