Into Unscientific

Chapter 643 Atomic Bomb Theory. Complete! (Down)

 After deciding on the internal grouping.

 Chen Nengkuan and others stopped procrastinating and immediately began to calculate their own data.

ˆ “.”

 At this moment.

Looking at the blank calculation paper spread out in front of him, Chen Jingrun couldn't help but feel a little surging and agitated.

He is actually a very introverted person. He will get nervous and blush when he encounters a lot of people. In the words of later generations, he is very "socially afraid".

 For example, a few years ago.

 Because of his excellent academic performance at Xiamen University, he obtained the qualification to teach at Capital No. 4 Middle School and was sent to give a speech at Capital No. 4 Middle School.

That speech was not just a sharing of experience, but also related to Chen Jingrun’s follow-up work in No. 4 Middle School.

As a result, when facing dozens of students in the audience, Chen Jingrun panicked because he was too nervous, causing his prepared speech to be incoherent.

 In this case, Capital No. 4 Middle School made the decision not to accept Chen Jingrun and returned him to Xiamen University.

 So on the personal information of later generations Chen Jingrun, you can see such a work resume - [Graduated from Xiamen University in 1953, and was later assigned to teach at Capital No. 4 Middle School. In 1954, he served as data clerk of Xiamen University. 】

Although Wang Yanan, the president of Xiamen University, still took good care of him after he was "returned", he was promoted to the Institute of Mathematics of the Chinese Academy of Sciences as an intern researcher four years ago.

 But to be honest, Chen Jingrun’s life was not a happy one.

 Because underneath his seemingly simple appearance, he has always had a fiery heart.

His favorite poem comes from Li He's "Thirteen Poems of Nanyuan", which is the famous line "Why don't men wear Wu hooks and collect the fifty states of Guanshan".

This poem was excerpted no less than fifty times in his lifetime. Banners with hand-made excerpts were posted in his study, entrance hall, and bedroom, which shows his love for this poem.

However, due to his personality, Chen Jingrun knew very well that he would not have any chance to carry a gun on the front line in this life. It should be said that he would not even have much chance to contribute to the country.

 The result was unexpected.

The organization suddenly found him not long ago and transferred him from the Mathematics Department of the Chinese Academy of Sciences to the 221 base far away in the Jinyintan grassland.

 What surprised him even more was that the project this base was responsible for was actually

 Atomic bomb? !

He will probably never forget the day he arrived at the base. Li Jue, the director of the base, patted his shoulder and said to him:

“Comrade Jingrun, the motherland needs your brain.”

 So from that day on, Chen Jingrun made a decision:

He will definitely do his best to expand territory for the motherland on the smokeless battlefield of mathematics!

The pen is his weapon, and the calculation paper is his shield. He will calculate whatever data the base needs.

 In the past years, he had assisted Xu Yun in many small battles as a member of the arithmetic team.

 But today it is different.

What they are facing today is a decisive battle at the Huaihai level!

　　Although it seems that I am only just one step away, the advantage of the last call is that my bald man has already "regained the lost ground" and reached the other side.

Therefore, you must be extremely energetic and never make the same mistakes as someone else.

ˆ “.”

Then Chen Jingrun took a deep breath and turned his attention to the manuscript paper in front of him.

 He ​​and his teacher Hua Luogeng were responsible for the calculation of explosion pressure, which is also a relatively complex parameter in atomic bombs.

Since the critical mass of the same type of nuclear material is inversely proportional to the square of the density, the critical mass depends greatly on the conditions of explosive compression. This is a concept that has been mentioned very early - although I guess not many people have remembered it.

And this kind of compression condition cannot be evenly distributed in space, so the highest explosion pressure value must be calculated.

This is actually not difficult to understand.

Just like when you use a pressure cooker to cook rice, the internal pressure of the container has a limit. If it exceeds the limit, the pressure cooker will turn into Melody's head and explode into countless pieces in an instant.

The same applies to the explosion pressure value. The only difference is that the direction of the explosion pressure is controllable and calculable.

 In fact, the base research team had calculated the explosion pressure parameter long before today, but the accuracy of that parameter was limited, so Chen Jingrun had to push it back by two decimal points.

Don't look at [Push back two decimal points], it seems very simple, but in fact it is very difficult. Put it this way, look at the balance of your bank card and think about how difficult it is to add two 0s to the integer digits. .

 Hence very quickly.

Chen Jingrun wrote a formula on the paper:

ˆ【△P=0.084/R+0.27/R+0.7/R】.

  This is the basic calculation formula for point explosion shock wave overpressure, which is the most basic concept in the field of shock waves.

However, this formula mainly describes longitudinal waves with strong discontinuities in air parameters and is not suitable for nuclear explosion conditions, so Chen Jingrun still needs to make some minor changes to it.

  One minute later.

 A simple formula with slight modifications appeared on the paper:

  【△P=ρ1(Du1)At(u2u1)12g04g000g00μg0νR+ρ1(Du1)At(E2+u222E1u122)13g23g101g00μg0νR+p2Au2tp1Au1t19g33g202g00μg0νR+21g29g303g00μg 0νR+12g10g000g00μg1νR】

Then looking at this formula, Chen Jingrun secretly set a time for himself to solve it:

three minutes!

 While Chen Jingrun and others were calculating their respective tasks.

Xu Yun on the side also dutifully poured a glass of water into Da Yu’s tea cup:

 “Come on, Da Da, have a drink of water.”

no way.

As an outsider in the non-atomic energy field, Xu Yun is really unable to do much more than the computing tasks they are currently responsible for - after all, the span of expertise is really too large.

If it were someone else, Xu Yun would still be thinking about whether he could be better at computing, but now he is partnering with a humanoid self-propelled supercomputer that is larger than

If he insists on helping, there is no guarantee that as soon as his end calculates a certain result, it will be three or five steps later than the other end.

So Xu Yun could only build a water pouring machine honestly to ensure that larger water cups would not bottom out.

 In fact, Xu Yun believes that his work is quite important—no matter how powerful the CPU is, it needs water cooling to match it, right?

 Our water-cooling level is not to mention the second and third generations of Dragon God, but it can also be regarded as a Valkyrie GL360. It costs several hundred yuan.

Well, An and Da together are really strong!

 And opposite Xu Yun.

Hearing this, Da Da was stunned for two seconds before taking the water poured by Xu Yun:

“Oh, okay, thank you, Comrade Xu Yun.”

"Comrade Yu, you are too polite. This is a trivial matter."

Hearing this, Xu Yun immediately waved his hand and at the same time poked his head towards Yu Da’s calculation paper:

 “Greater than, where have you been?”

Hearing this, Da Da glanced at Chen Nengkuan and others beside him, and deliberately lowered his voice in order not to disturb other companions:

“You see, the phase data of secondary fission have been calculated, and two parameters have been optimized.”

 Xu Yun nodded slightly.

Although he does not know much about the field of atomic energy, he still knows some contextual concepts - although knowing these concepts is actually meaningless.

Just like many military fans in later generations who have a clear understanding of some firearms modules, they are completely confused when it comes to the development of weapons.

 The phase data of secondary fission is greater than the secondary cylinder parameters that need to be calculated. This is an internal progressive structure of the atomic bomb, mainly involving high-energy neutron flow.

Its structural design requires about seven to nine parameters, seven are the minimum and nine are the best. In future generations, it will also be a standard problem that requires supercomputing to solve.

However, the name "Greater Than" itself represents a miracle, and no matter how difficult this problem is, it is still easier than the hydrogen bomb, so Xu Yun was not too surprised that "Greater Than" can be calculated.

 No, to be precise, it should be.

 It takes so much time to calculate only two parameters, but it is a bit slow.

From Xu Yun's point of view, I don't know why, but he seems to be a little out of shape today.

If I remember correctly, I didn’t fall in love at the base.

However, things like status are not static. It is normal for top students to occasionally get low scores, so Xu Yun did not delve too deeply into it.

 After filling up the water.

He quietly left his seat and pushed the wheelchair to Lu Guangda's side:

“Director Lu, how are you doing here?”

 “Oh, it’s Xiao Xu.”

Lu Guangda was originally staring at a calculation with his eyebrows furrowed without saying a word. When he saw Xu Yun, his expression suddenly brightened:

“Here, come and look at this problem—I’m stuck.”

Xu Yun blinked:

“Stuck? Director Lu, I remember you are calculating the optimization of the six-factor formula, right?”

 Lu Guangda nodded:

 “That’s right.”

 Those who know Baidu should all know it.

Each fission of U235 releases approximately 192.5 MeV. The energy released comes from mass loss, and the value can be calculated through Lao Ai’s mass-energy equation.

 There are two types of U235 fission: spontaneous fission and induced fission. Spontaneous fission has a half-life, and induced fission requires external supply of neutrons.

If certain conditions are met, U235 can be self-sufficient - this is the so-called critical and supercritical concept.

 The purpose of a reactor is to maintain criticality, while the purpose of a nuclear bomb is to be as supercritical as possible.

The specific numerical calculation is a four-factor or six-factor formula, which is the fuel reproduction ratio, neutron reproduction ratio, neutron reproduction ratio, neutron utilization rate, neutron loss factor and burn-up rate.

 This is also a very complex problem, otherwise Lu Guangda would not be responsible for the calculation himself.

Xu Yun had learned a little bit about the six-factor formula in his elective course back then. Although he couldn’t say he was very familiar with it, it was at least within the scope of what he could understand.

So he stretched his head and glanced at the paper a few times, but soon he was slightly startled:

“Huh? Director Lu, don’t you have no problem with this?”

At this time, Lu Guangda saw a series of formulas written on the calculation paper in front of him. His ideas seemed to belong to his own school, and only some derivation processes were left before the final result.

Although these derivation processes are a bit complicated, for Lu Guangda, when the idea is determined, it is no different from elementary school mathematics.

“Hey, who said it was a problem with the six-factor formula? I thought of other things during the optimization process.” Xu Yun said (for the second time):

 “Oh? Tell me about it?”

Lu Guangda quickly pulled away the chair next to him, allowing Xu Yun enough space to place the wheelchair, and explained at the same time:

“Look here, it’s the neutron multiplication ratio.”

“We will experience neutron capture when an atomic bomb explodes. It can happen about three times during fusion.”

“So I was thinking, if we could synthesize a nuclide and allow neutron capture to fully occur, what would happen?”

 Xu Yun was suddenly startled.

But Lu Guangda seemed to be interested, and he quickly pulled out a brand new piece of calculation paper:

“For example, the number of protons in U235 is 92 and the number of neutrons is 143. The number of neutrons in U236 is 144 and a maximum of 146 can be captured.”

“What if we had the technology to allow it to continue to capture neutrons? Let’s say 160, 180 or even 200?”

“Didn’t Jensen propose the concept of magic numbers in 1948? I personally think that if we start from this perspective, this new nuclide may have some extremely unique stable states.”

“Of course, this is just my personal conjecture. After all, the Coulomb barrier is a big problem.”

Maybe it was because Lu Guangda was too involved that he didn't notice that Xu Yun's expression had become dull at this time.

ˆWTF

 Lu Guangda actually thought of this?

Those who haven’t been **** off by their junior high school chemistry teachers should all know this.

 Elements with a proton number greater than 103 are called superheavy elements. Superheavy elements are extremely unstable. The longest half-life is generally only a few minutes, and the shortest half-life is only a few milliseconds or even microseconds.

 But this is not absolute.

In 1963, while working at Argonne National Laboratory, Nobel Prize winner Maria Meyer discovered that the number of nucleons of highly abundant isotopes has a regular pattern:

 Nuclei with nucleon numbers of 2, 8, 20, 28, 50, 82, and 126 are particularly stable.

 So she named these numbers magic numbers, that is, magic numbers.

Later, Jensen successfully explained the existence of magic numbers under the assumption of strong spin-orbit coupling, and proposed that the existence of magic numbers reflects the shell structure of the atomic nucleus:

 When there is a magic number in the nucleus, the nucleons are filled with a certain energy level and no nucleons jump to a higher energy level, so these nuclei are quite stable.

If the number of neutrons in the nucleus is used as the abscissa and the number of protons is used as the ordinate, and all stable and radioactive nuclides are plotted on the nuclide diagram, then it can be clearly seen that the known atomic nuclei in nature are along the It is distributed along the β stability line and forms a continuously distributed peninsula in the plane formed by the number of neutrons and the number of protons as coordinates.

 The magic numbers are 2, 8, 20, 28, 50, 82, and 126, all of which happen to be at the apex of this peninsula.

 Finally, based on this theory, a famous theory or conjecture emerged in the world of physics:

Suppose there is an atomic nucleus that is a double-phantom nuclear material with a closed shell filled with neutrons and protons, wouldn't its nucleus be stable enough to support an ear without collapsing?

This theory is the famous stable island conjecture.

 In the later life when Xu Yun traveled through time.

 The more recognized stable island nuclide is the nuclide with Z=114 and N=184, which is the so-called element 114.

However, at that time, the chemical community had only synthesized element 118, Og, and element 119, Uue, was still being synthesized.

Of course.

 Seeing this, some students may be surprised:

 That’s not right, 118 is greater than 114, which means that nuclide 114 has been synthesized, so why is it still a conjecture to say that it is a stable island?

 The reason is very simple, don’t forget that the N at the end is the number of neutrons.

One Z alone is not enough, Z+N=298 is required.

  So far.

Scientists have obtained seven isotopes of element 114, the smallest atomic weight is 284, the largest is 290 - and the atomic weight predicted by Stable Island is 298.

 Hence, there is still a long way to go before this theory can be confirmed.

but

 Once the nuclide Z=114, N=184 is really discovered and confirmed to be in line with the stable island theory, then the fun will be great.

Not to mention the impact of this new nuclide on physical and chemical models, just one of its applications is enough to make your heart beat faster - its lifespan is as long as 1049 years. This is a type of nuclide that can be used in controlled nuclear fusion. white.

 Although this is only one of the theoretical directions and no one knows whether it is true or false, it is undeniable that its research value is still very high.

 Ten thousand steps back.

Even if controllable nuclear fusion is not considered, the stability island theory is of great help to the understanding of microscopic particles.

Now the rabbits already have a tandem electrostatic accelerator, but what is missing is actually some theory.

 Just like you have a large number of modern weapons in your hand, it seems that you can go up F2A, but in fact if you have one or more correct tactical systems, the effect on the battlefield will obviously be higher.

So Xu Yun thought for a while and asked Lu Guangda:

“Director Lu, do you know about the shell model?”

 Lu Guangda turned the pen twice:

“Shell model. Is it the nuclear model proposed by Meyer and Wegener?”

Xu Yun nodded:

“Yes, that’s the model—Meyer was also the originator of the concept of magic numbers.”

 Shell model.

This is a nuclear model proposed by Meyer, Wegener and Jensen in 1949. They later won the Nobel Prize in 1963 for it.

 This model points out that similar to electrons in atoms, there are many shells in the nucleus.

 Corresponding to different energy levels, protons and neutrons move in different shells and "jump" back and forth, and they also satisfy the Pauli exclusion principle.

The reason why a noble gas is chemically stable is that its outermost shell is filled with electrons, so it has greater stability. Similarly, when the shell in the nucleus is filled with protons and neutrons, it will also have greater stability. stability.

The shell model better explains the stability of some nuclides, and can also better predict or explain the spin and parity of the ground state of the nucleus.

 Take oxygen 17 as an example.

8 protons fill 3 proton shells, 8 neutrons fill 3 neutron shells, and there is 1 extra neutron.

 That is, the total angular momentum of the inner full shell is 0, and the total parity of 8 protons and 8 neutrons is +1.

 This means that the spin of the oxygen 17 nucleus, and its parity, are entirely determined by the spin of the 9th neutron.

 Xu Yun then drew a simple diagram on the paper and said:

“Director Lu, now the shell model has proven its accuracy. If you introduce this model into your idea, what do you think will happen?”

 This time.

 Lu Guangda thought for a long time and then said after careful consideration:

“Protons and neutrons must obey the Pauli exclusion principle. At the same time, the electromagnetic repulsion between protons is offset by the strong interaction force, and the semi-classical binding energy formula is established.”

“That is, if the Coulomb barrier can be broken, it should be fed back into the change in the magnetic moment of the atomic nucleus—at least a partial change?”

Snapped!

Xu Yun smiled and snapped his fingers:

"bingo!"

 According to the shell model, the inner layer of an atom can be regarded as a sphere.

And the nuclei in the outer valence space bulge high, just like a towering iceberg rotating at high speed around a large water ball.

Since protons are positively charged, this "iceberg" will also bring up a "tidal wave" of current.

 Hence, the larger the magnitude of the iceberg, the larger the energy level of the tide will be.

 This part of the changing energy level is actually the Coulomb barrier that Lu Guangda hesitated about, which is also part of the magnetic moment of the atomic nucleus.

 At the macro level, or at the data level, the value of this change is.

 Electrical quadrupole moment.

 In the current situation where the base is used for tandem accelerators, it is still very simple to verify this change.

  After all, most of the nuclides after No. 102 were successfully synthesized inside the accelerator.

 After thinking about this, Lu Guangda's face suddenly became a lot more happy.

  After all, for people like him, if a problem remains unresolved, they will be troubled and unable to sleep.

He looked at Xu Yun with gratitude and patted Xu Yun on the shoulder:

 “Xiao Xu, thank you for clearing up the confusion.”

Xu Yun's injury was not completely healed at this time. After being patted on the shoulder by Lu Guangda, he couldn't help but bared his teeth:

“Director Lu, you are too polite, it hurts, it hurts, it hurts”

Lu Guangda couldn't help laughing.

Then Lu Guangda brought his mind back to reality and began to calculate the optimization content of the six-factor formula.

 But it has reached this point.

 Whether it is Lu Guangda or Chen Nengkuan, the rest is basically just a matter of mathematical derivation.

 After the theoretical ideas are solved, the test is purely personal calculation ability - which is a quality that almost everyone has in today's theoretical groups.

 Three hours later.

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　——

Yuda gently put down the pen in his hand and rubbed his aching eyes:

 “Huh, it’s finally done.”

 (End of this chapter)