Chapter 75

On this day, a big event suddenly happened in the spacecraft: academician Ding of the wolf design bureau made a voice and wanted to recruit a graduate student among undergraduate graduates. As a result, it caused a sensation among the whole group of candidates!

Academician Ding has always trained doctors, but this time he wants to recruit a master, and the opportunity is extremely rare.

Everyone clearly knows that contacting these top bulls in advance will have a significant impact on their future academic career.

Because there are too many applicants, it is impossible to come for an interview. The staff had to strengthen the hard conditions for registration before reducing the number of candidates to less than 50.

Zhang Yuan opened the registration interface and saw his hard conditions and test results. He was still able to sign up, which was a slight relief.

At this time, Professor Wang Zhong sent a video.

"... that old guy has been convinced by me. It's up to you next. If there are more suitable people than you and they are competitive, no wonder others. Are you confident in choosing one of the fifty masters? "

"Yes!"

"That's good. I'll wait for your good news!"

……

After a short preparation, it was finally the day of the interview.

There are five interviewing teachers, two of whom are former colleagues of their father. They look familiar and all cast kind eyes.

Sitting in the middle is Professor Ding Zhaodong. On the far left is captain Ma Tao, who also looks at Zhang Yuan kindly.

"Don't be nervous, young man."

Captain Ma glanced at the materials on the table and first asked, "you are Lao Zhang's son. We all know that. There is no need to introduce yourself. I have a question. What do you learn most from him? "

Nervous, with enough strength, he is not nervous at all.

Zhang Yuan came at random: "humble personal morality, excellent learning habits, unrestrained life style of foreign objects, lofty goals and ideals!"

"Stop!"

Seeing that the surrounding professors showed a slightly strange smile, Captain Ma asked again, "tell me about his shortcomings. What shortcomings can't you tolerate?"

Zhang Yuan was stunned. Is there any old gap between the captain and his father?

Or is it just a joke to ease the tense and serious atmosphere?

be on the cards.

Zhang Yuan thought for a moment and said, "he always criticizes others with his IQ, which I think ordinary people can't tolerate. Many things he thinks are very simple, so he casually tells others to do them, but others have to do them for a long time, and they may not even be able to do them... So he always loses his temper for no reason. "

Everyone smiled.

Zhang Yuan doesn't understand his answer. Is it good or bad.

Then there is a serious question time. Naturally, it will not be that kind of ordinary question.

One of the professors asked bluntly, "I once read your paper on robot kinematics, which is really a very good article. However, have you considered the constraint calculation of less DOF robots? "

"In reality, many industrial robots do not need too many degrees of freedom, and the algorithms are also different... Do you know anything about the 2-rps-2-sps four degree of freedom parallel robot? Just say an idea. There's no need to talk at length. "

Zhang Yuan thought for a few seconds. In fact, this problem is fairly basic: "in terms of structural complexity and production cost, the fully symmetrical parallel mechanism has great advantages... The characteristic matrix of the motion branch chain of the four degrees of freedom motion is 3T1R, 2T2R, 2T ⊥ 2R, 1T3R, 3t2r, 2t3r, 3t3r."

"We first discuss the mechanical generator in the form of single open chain connected by motion in these 7..."

Although he was told not to talk at length, he said it for more than ten minutes.

The professor narrowed his eyes, nodded and said, "the answer is good."

It's not easy to come up with so many ideas in such a little time. It shows that Zhang Yuan has solid basic knowledge, quick thinking and smart mind.

"... have you studied the latest optical chips? Why not vigorously develop quantum chips with stronger computing power? "

Zhang Yuan thought for a few seconds and replied: "... Photonic chip is a computing framework based on photonic circuit, which is equivalent to using countless micro optical switches on the chip, which is similar to the logic gate in semiconductor chip... Photonic chip uses the combination of light with different wavelengths, phases and intensities in complex mirrors Information processing is performed in an array composed of filters and prism structures. "

"... like microelectronics, it is a semiconductor architecture based on silicon materials, so it is equivalent to the extension of traditional chips. Its computing power is more than 10000 times that of ordinary silicon-based chips, and there is room for upward development with current technology. "

"Although the computing power of quantum computer can reach 100 million times or even 1 trillion times that of silicon-based chip, it must realize a relevant number of quantum entangled states. 40-50 entangled states are the limit of current technology, and it is very difficult to improve upward. But the computational power of this number of entangled states is not as good as that of traditional silicon-based chips... "

"Therefore, although quantum chip is good, it is difficult to develop upward without a major theoretical breakthrough, so it is not the mainstream of current research."

"Very good, very correct." The professor nodded slightly. This not only examined the theoretical basis, but also the breadth of knowledge.

Many professors raised many questions, and Zhang Yuan responded one by one, calmly and complacently.

"I have a question, too." Ding Zhaodong suddenly opened his mouth.

"Excuse me."

Academician Ding Zhaodong said slowly, "what do you think of the industrialized production of the new civilization? What do you think is the biggest factor restricting the development of new civilization? "

Is the problem so big?

Zhang Yuanqing cleared his throat and replied, "we do have some good industrial foundation. For example, the spacecraft carries the most advanced lithography machines, some nano material production rooms, and some industrial motherboards. We can produce some parts, but many upstream industrial chains are completely disconnected. "

"For example, chloroform, caprolactam and acrylic acid, the most basic chemical raw materials, have only a small amount of inventory, and there is no way to produce them when they are used up. If biosynthesis is used, the cost is too high. "

"If we successfully reach the target planet and obtain a lot of material resources, we have to start with the development of the most basic raw materials. I think the biggest factor restricting the development of civilization is... Population. The population is too small to make the whole industrial system work. "

"I once read a report that the minimum population to maintain the earth's industry is 1.6 billion. Although the quality of our population is high enough, the number is only 500000, which is far from enough. "

"It makes sense. In fact, this is what we are worried about..." before academician Ding answered, a professor nodded first.