Chapter 1341 Implicit Density Functional Method

Young's modulus ≥ 2.1TPa, failure strength ≥ 80N/m...

Judging from the series of parameters given here, Lu Zhou immediately thought of a cable with a very high tensile strength, and then thought of impact-resistant coatings used on automobiles or aerospace equipment. .

As for where this thing can be used...

That would be more useful.

Simply speaking, it can be used as a cable, and it can be used on a space station when viewed from the sky. It can be used as a traction rope for fixing heat sinks and solar panels. When placed on the ground, it can be used as a suspension material for engineering equipment. As an arresting cable on the deck of an aircraft carrier.

Especially the latter, this thing is not usually expensive.

And these are just some of the uses for this material.

Lu Zhou believed that when this material with high Young's modulus and high breaking strength came out, countless people would be able to think of uses for him that he hadn't thought of himself.

Back to the research itself.

For the technical standard given by the system, the best option that Lu Zhou can think of is a carbon-based material with high tensile strength, light weight, and strong plasticity.

Especially carbon fiber and a series of graphite-derived reinforced composite materials.

This kind of material not only has a broad imagination space in theory, but it is also his old profession when it comes to the research of computational materials science. When he first started his research on computational materials science, he started with carbon materials.

Therefore, this task is not difficult for him at all.

It's like giving it for nothing!

After leaving Professor Wang Qingping's laboratory, Lu Zhou did not stay at the Jinling Institute for Advanced Study, but went straight back home.

When modifying the mathematical model according to the experimental results, some ideas about the theoretical research of computational materials suddenly appeared in his mind.

Perhaps because both mathematics and physics have been upgraded to LV10, Lu Zhou found that his sensitivity to numbers and physical phenomena has reached a state of perfection.

Even if it is just a clue that is so small that it can be ignored, it can be infinitely magnified in his eyes and become a key that can be touched by both hands.

No matter where this inspiration comes from, there is only one thought in his mind at this moment.

That is to record this inspiration before it dissipates.

Going upstairs to the study room, after ordering Xiao Ai to make a cup of coffee for him, Lu Zhou sat at the desk and spread the draft paper brought back from the laboratory on the table.

"Material A synthesized by the experimental process designed according to the original model has a low density, and a fluffy mass is formed after deposition, and the diameter of the carbon nanotubes is extremely uneven..."

"The reason for this result should be that monomer acrylonitrile undergoes insufficient free radical polymerization, forming a large number of intermediate products, resulting in insufficient third-stage reaction...and finally forming that foamy mixed substance."

"Tsk tsk, interesting."

What interested Lu Zhou was not the frothy mixture, but some very interesting phenomena he discovered when he revised the calculation model.

After thinking about it for a while, he picked up a pen and wrote a line of text neatly on a piece of blank draft paper.

【Implicit Density Functional Method】

Looking at the inspiration of this line being refined into words, the corner of Lu Zhou's mouth could not help but pull a smile.

Generally speaking, when a problem is clearly written, it is already half solved.

At least, that's the case for him!

The so-called implicit functional density is a computational materials science method relative to the explicit functional density, and it is a relatively popular research direction in the theoretical research field of computational materials science.

As we all know, the traditional exchange-correlation energy functional is an explicit functional expressed directly by the electron density function, while the expression method using the Kohn-Shan orbital wave function as a direct variable is an implicit functional.

The simplest implicit functional is the Fock exchange energy, which is often called exact correlation in the context of density functional theory.

For molecular systems, the implicit density functional method can achieve the accuracy equivalent to the second-order many-body perturbation theory with a relatively small amount of calculation, so the implicit density functional method is widely regarded as a method with broad Prospects for research methods in computational materials science.

However, despite such advantages, its disadvantages are also obvious. For example, the accuracy is limited, including the inability to accurately describe van der Waals interactions, etc., which is almost fatal for the study of solid materials.

Therefore, the implicit density functional method has relatively little application in the study of solid materials, and has only made certain progress in some fields...and this is still under the condition that the computing power has been greatly developed.

At present, the implicit correlation functional based on the adiabatic correlation fluctuation-dissipation theorem has attracted widespread attention in the academic community, which is widely regarded as a breakthrough in the study of overcoming the shortcomings of the implicit functional density.

However, the problems of this type of functional are not small, especially the huge amount of calculation will be difficult even for the most powerful traditional computer, so the current research direction is still in the exploratory research on simple systems.

What Lu Zhou has to do now is to extend this method from a simple system to a relatively complex carbon material research!

Once this research is successful, it will be of great help to the entire research field of carbon composite materials, and its significance will even surpass the "Young's modulus ≥ 2.1TPa, failure strength ≥ 80N/m..." he studied. The material itself!

The pen in his hand didn't stop at all. After completing the title, Lu Zhou quickly went deep into the exploration of the proposition itself.

【According to the H-K theorem, the ground state energy functional of the system can be expressed as: EG{P(r)}=E{P(r)}+∫V(r)ρ(r)dr...】

[The functional E{P(r)} can be expressed as: E{P(r)}=T{ρ(r)}+1/2∫∫{ρ(r){ρ(r)drdr+Exc{ P(r)}...]

【…】

Lines of calculation formulas flow out from under the pen tip, like a trickling stream, and together with the bursting inspiration, they merge into a river and flow into the sea!

All inspirations about matter are woven into a language that can be recited by visible numbers at this moment.

And under the shroud of this huge net, all forces and physical properties are included, all abstracted into mathematical language by the tremblingly rigorous logic, and answered by mathematical methods!

"Then, is the introduction of the Shrodinger equation—"

While muttering softly in his mouth, the tip of the pen pinched by Lu Zhou at his fingertips was like a sharp dagger, drawing a powerful trajectory on the paper, and piercing through the dense barrier that covered the end of the maze. fog.

Looking at the results that were almost on the paper, Lu Zhou's pupils became brighter, and his slightly frowning brows finally relaxed into a smile.

Although there is still a long way to go before the end.

But his intuition about science told him that he was very close to the finish line!

Time passed by every minute and every second.

The sun also gradually moved from the center of the sky to the corner of the sky.

As the sky outside the window finally completely darkened, the street lights on both sides of the tree-lined path began to light up. At this moment, Lu Zhou finally raised his head and let out a sigh of relief, and stopped the pen that was almost pinched to heat.

"...the implicit density functional approach holds great promise for carbon composites as well, at least now that it has been extended to this field."

"At the same time, this can also be regarded as a breakthrough in extending the method from a simple system to a complex system."

"Although there is still room for further digging behind this."

"But, that's all for now."

After that, Lu Zhou smiled with some satisfaction, and put the pen in his hand aside.

And almost at the same time he just put down the pen, a line of light blue text appeared in front of his eyes unexpectedly.

At first, he thought he was wrong, and Lu Zhou blinked subconsciously.

However, the line of light blue text was not dimmed by his blinking, it was still so clear and impossible to ignore...

[Congratulations to the host, the task is completed! 】