Scholar’s Advanced Technological System

In the three days of the Mathematics Modeling Competition, two major classes will be flushed out.

Although it was ordered to take leave, considering that it was not a good idea to take time off from the first class, the Ark decided to send the note personally, so it would not bother the class leader.

Look at the schedule information given by the teaching office. The big teacher's name is Lee Rong-eun and he is a highly qualified old professor. After asking for the phone number in the school complex, the ark made a phone call to confirm that the teacher was in the office, and then went there with a fake note.

After knocking on the door, the ark walked in and placed the note on the desk, indicating its intention.

“Leave?” Looking at the fake eye strip, Professor Li took off his old glasses and looked up and smiled, "Your name is Ark, isn't it? ”

“Yes.” The ark nodded.

Professor Li laughed and said, "Well, I'll test you two questions. If you solve one, I'll approve your note. ”

And this operation?!

The Ark is a fool.

“What, scared?” Ron Li asked with a smile.

“No,” said the ark, shaking his head, “Teacher, ask a question. ”

“Question number one, take it," dumped an A4 paper in the hand of the ark, Li Rong En looked at the ark with a smile, and the old god said on the ground, “How much can you write? I want to see the process. ”

Are you ready for the title?!

The Ark always feels this guy is premeditated, otherwise how do I explain why this question has been printed on A4 paper?

However, even if you guessed a little, the ark didn't say anything and picked up the A4 paper to start reading.

[The half-life of the U238 core in a nuclear submarine is 4.5 × 10 ^ 9 years, with a 0.7% chance of decay becoming the U234 core, while emitting a high-energy photon, 93% of which is absorbed by submarine steel plates. In 1981, high-energy photons transmitted offboard by a former Soviet nuclear submarine number U137 were detected by a detector at 1.5m from the nuclear source (dotted). The instrument has a positive incident area of 22cm ^ 2 with an efficiency of 0.25% (one impulse signal can be generated per 400 incident photons) and 125 signals measured per hour.

① Average life of U238 core (LN2 = 0.693).

② Require the mass of U238 in the nuclear submarine (unit kg, take 2 digits)

Read the title and sigh softly in the heart of the ark.

Professor Li, who was called "The Four Demons of the Theater" by his predecessors, is that the title?

Anyway, next Monday is the first big thing class, and you can test yourself directly with this nuclear physics knowledge of baseball?

“Why don't you find a place to sit? ”

“No, it's right here. ”

After taking Professor Li's pen and draft paper, the ark stood by the desk, frowned and pondered for a moment.

Physics is not really his area of expertise.

However, after a summer of liver explosion learning, he stood here impeccably!

About five minutes later, the ark's eyebrows slackened and its tips moved.

[Laws of decay of radionuclides: N = N0e ^ (-λt)

The relationship between the decay constant and half-life is: N02 = N0e ^ (-λT12), whereby T12 = ln2λ is obtained

Write down these two lines of formula, the eyes of the ark flashed slightly.

He has succeeded in turning physical problems into high numbers.

Next, break it one by one!

First question!

The tip swims fast on A4 paper.

[(1) Mean lifetime of radionuclides t = λNtdtN0 = … = 1.1443T12

Available in proxy data, t = 6.49 * 10 ^ 9 years.

After sweeping the A4 paper, Professor Lee Rong-eun picked out his eyebrows and a funny look appeared in his eyes.

Without noticing the change in Professor Li's expression, he focused his attention on the ark on paper and began to answer the next question.

The number of high-energy photons produced by decay to U234 at dt time is -dN · n0 = n0λNdt

The efficiency of the photons passing through the steel plate is n1, and the number of photons passing through the steel plate in the dt time is calculated as dN1 = n0λNdt · n1

Number of photons entering the detector...

Number of signals generated in the probe…

The number of U238 in the submarine is calculated, and thus the number of U238 cores is calculated.

The number of U238 cores in the submarine N = 7.456 * 10 ^ 25 was calculated by substituting all the data for the ship.

However, just as he was preparing to bring N into M = N * 238u and finish his final blow to the enemy's spring water, Professor Lee Rong-eun suddenly spoke.

“Well, you're past that. ”

Ark:????

He didn't like it at all.

What do you mean, I'm past it?

I'm counting here, can't you just wait till I'm done talking!

“Professor, I haven't finished...”

“You've got it all figured out. You can figure it out if you're a junior high student," Ron Li said with a smile. “You can count it out if you want. Whatever. ”

The atmosphere was ruined and the ark was silent for a while.

The obsession with obsessive-compulsive disorder was unbearable, and he wrote down the results at the end.

Answer M = 29.634kg, take two bits about 30kg

The steps are correct, and the results are correct without suspense.

The ark ended the question with a full finish.

“Do you want to hear the second question?” Ron Li smiled.

Though the Ark wanted to say "no," he thought the professor had not yet approved his fake note and was helpless: “Go ahead. ”

Li Rong-en smiled and continued: “Relax, the second question is simple, just tell me the Kenan statement of the second law of thermodynamics. ”

The ark was relieved to hear the question.

He thought this professor's second question would come up with a problem he couldn't even write, knock him, warn him not to be complacent or anything. I didn't expect Professor Li to follow the set of cards, so I simply let him go.

Generally speaking, the second law of thermodynamics has two main expressions: the famous Kelvin expression and the one mentioned by Claus in his 1850 paper.

As for Kennan's statement, it is a relatively novel one that has emerged recently.

If you look carefully at the textbooks, you won't miss it.

That is...

“For a system with given energy, material composition, parameters, there is a stable equilibrium: other states can always be achieved through reversible processes.” The Ark repeats this statement as if it were a reverse text.

“Nice." Ron Li nodded in praise of the location.

This more cutting-edge statement will not be mentioned in the body of the textbook used by non-physics professions, but it will still be included in the appendix. Students who are generally not interested in physics will not go over there when they graduate.

If the Ark even had such clarity about this secluded knowledge point, it would be enough to prove that he had eaten the entire University Physics textbook.

After this shallow and in-depth examination, Ron Lee can now confirm that there is really nothing left to teach him about this course for undergraduate non-physics students.

Looks like Old Tang didn't brag. This kid is a talent!

In fact, the answer to the question is correct to approve the fake, which is a joke with young people.

Since yesterday, he's approved dozens of fakes for the mathematical modeling contest.

Even if the ark doesn't answer, he'll tweak two sentences at most, and eventually he'll approve it.

Signed the note, Li Rong-en flipped out the namebook in the drawer and drew two hooks on it, saying in the mouth of the elder.

“Ark. ”

“What's the matter? ”

“Are there any plans to study? ”

The ship thought about it and said in an uncertain tone: "Yes. ”

Who says anything about the future?

However, Professor Li's intuition was obviously not as acute as that of old Tang. He did not hear the uncertainty in the tone of the ark. Instead, he nodded in praise of the place and continued.

“Our Physics Department at Kim Dae is also one of the top universities in the country, humbly speaking, even if North Dae is first in line with us. But when it comes to research direction, superconducting physics and strongly correlated electronic systems, and condensed physics and material design, they're not as good as us. If you're interested in physics, you can come to me during the exam, and we at Carbon Nanotube Lab need the best in mathematics. ”

This is…

Are you implying that you're going to report it to his graduate school?

Ark's heart couldn't help but laugh. He's just in his freshman year and is still far from the exam.

But in any case, it was the good intentions of the teacher.

The Ark sincerely said: "Thank you teacher. ”

Li Rong-en nodded with a smile: "All right, take the fake note. This kind of competition has the opportunity to participate more, if you are politician. If you can't cure it, you can keep an eye out for research opportunities. Or next year, when you're in junior year, you can ask me, ask Miss Tang. ”

The Ark laughed and expressed its gratitude, saying no more, and quickly said goodbye with this hard-won note.