Siheyuan: I eat melons while doing scientific research

Chapter 1436 Running into the line of fire (4k)

Although carbon fiber produced using the PAN process is not insignificant, its sensitivity is undoubtedly not as high as that of ferrite.

After all, carbon fiber is intended for civilian use, while the ferrite-related products in Gao Zhendong's possession are all military secrets.

"Alright, now that we've finally figured it out, you can speak your mind freely," Gao Zhendong said to the comrades on the phase shifter side.

"Committee Member Gao, we mainly wanted to see if there was anything we could do to help. As for specifics, we can't say for sure right now, because to be precise, we don't know which one to use," said the colleague from the Applied Chemistry Research Institute.

Gao Zhendong was also in a bit of a predicament. This was a real problem. He didn't even know the problem, and he didn't know if he could handle it.

You need keywords to search, right? The ferrite family is quite large.

He thought for a moment and asked, "Are any of the RF engineers here today?"

To be honest, we should start by looking at the people working on radio frequency (RF) technology.

A comrade next to him raised his hand: "Committee Member Gao, I'm here."

Judging from his appearance, it seemed as if he had met Gao Zhendong before. At the very least, he seemed to know Gao Zhendong quite well.

Gao Zhendong turned to look at him: "Phase shifter, are you going to use it in radar?"

“Yes.” Committee Member Gao’s expertise in radar was indeed exceptional; he was able to immediately deduce its applications.

"Oh, I know what kind of radar you're making, a phased array, right?"

"Ah, right, right, right..." In front of Committee Member Gao, there are indeed no technical secrets; he knows more than you do.

"What about the frequency band?" Gao Zhendong asked the core question again.

"P-band, around 450MHz."

Gao Zhendong smiled, "Then it must be it, there's no mistake."

The P-band is 230MHz~1GHz, with wavelengths of 130cm~30cm, which falls within the range of meter-wave radar. Decades later, its most famous function is anti-stealth, but there is actually another function that many people have not noticed.

Long-range surveillance, and the kind of ultra-long-range surveillance, thousands of kilometers.

It is the band of Citibank's Pave Paws long-range missile early warning radar.

No one has thought of using meter-wave radar to counter stealth yet, since stealth fighters are still in the prototype development stage. So there's only one left. If there was some uncertainty before, Gao Zhendong is now certain that it must be something he plans to use on that ultra-long-range radar.

"Hehehe, ultra-long-range radar...that's really fast."

Well, there are no secrets at all. However, given Gao's knowledge, these things are naturally impossible to hide from him, and the comrades were prepared for that.

I just don't understand what he meant by "really fast," or what he meant by "really fast."

With this, things became much easier for Gao Zhendong.

After a moment of contemplation, Gao Zhendong asked, "Well, what's the biggest problem right now?"

"We're still researching which type of ferrite is most suitable." The RF engineers are quite straightforward; although this progress is somewhat embarrassing, there's no need to hide it from Committee Member Gao.

Gao Zhendong nodded, pretended to think for a moment, and then said with certainty, "Mn-Zn ferrite."

"Huh? That's it?" The comrades were slightly surprised, mainly because manganese-zinc ferrite was one of the earlier types of ferrite, and it felt outdated and inconvenient to use in high-tech equipment.

It just feels like something's missing.

However, since Committee Member Gao answered this question through thought, there must be a reason behind it. Once the comrades realized what was happening, they became happy.

Manganese-zinc ferrite is relatively familiar to them, and there is really no problem in manufacturing it. In fact, some comrades had even studied it before.

Putting everything else aside, just those five words "manganese zinc ferrite" alone make today's trip worthwhile!

"Committee Member Gao, how did you make your judgment?" Some comrades were very curious about this, or rather, they wanted to learn.

Gao Zhendong laughed and said, "Actually, there's no need to think so much. You've probably used manganese-zinc ferrite before, right? Just not for phase shifters. But its characteristics are inherently suitable for this band, and that doesn't change because of your specific application. Keep things simple. If I had to say, one consideration is a saturation magnetization of 4πMs above 2000G, and the other is a Curie point of no less than 150 degrees Celsius, while also having low losses. After all that, it's pretty much what we need."

I've learned it! This isn't just based on experience; it's a well-reasoned deduction.

Just as the comrades were writing furiously, Gao Zhendong laughed and said, "If you really think the name 'manganese-zinc ferrite' is too corny, there are ways to solve that..."

"any solution?"

"Hmm... spinel-type manganese-zinc ferrite, that sounds like a more sophisticated name," Gao Zhendong joked.

The comrades looked on with mixed feelings of amusement and exasperation. Committee Member Gao was quite humorous, saying that manganese-zinc ferrite is spinel-type, so there is actually no change; it's one team with two names.

“Actually, yttrium iron garnet (YIG) will also work. In the P-band, YIG is suited to higher frequencies, while Mn-Zn is suited to lower frequencies.” Gao Zhendong wasn’t entirely joking; he genuinely knew that there was indeed something that could be used in this band.

The comrades were overjoyed and quickly wrote it down. To have a choice was truly wonderful. It just goes to show that Committee Member Gao wasn't joking; there was always something to gain after a joke.

"YIG has a higher frequency, while manganese-zinc has a lower frequency. It seems that YIG is more suitable."

"YIG is very expensive, while manganese and zinc are only a few dollars, and that radar has a considerable area."

Not to mention now, even decades from now, the price of YIG will be much higher than that of manganese zinc, by several thousand times.

Gao Zhendong knew that the radar eventually had a radar array area of ​​800 square meters, which was quite exaggerated.

So if you want to use YIG, you probably can't afford it, not even for strategic projects, it's just too expensive.

Gao Zhendong laughed and said, "Actually, manganese zinc also has its advantages. Not only is it cheap, but its saturation magnetization is also higher than that of YIG."

"However, the manganese-zinc ferrites we can prepare now have a rather high loss, typically exceeding 2000 mw/cm3 under typical conditions... This is really a bit exaggerated."

Gao Zhendong was shocked when he heard this. How much? How much does this thing cost? If he remembered correctly, the worst performance he could compare it to in the patent documents he found was only 1200mw/cm3.

But thinking about it again, the patents used for comparison, even at their worst, are still at the level of the 21st century, while we are only in the 1960s now, so it's normal for them to be this bad.

Gao Zhendong laughed: "What if I gave you a way to reduce the loss of manganese-zinc ferrite to below 200mw/cm3?" The comrades who worked in radio frequency and chemistry almost jumped up.

How much? How much? Did you hear me right?

"Committee Member Gao, are there any mistakes with the numbers?"

Gao Zhendong, with an air of self-assurance, said, "No mistake. Actually, this was originally the third type of ferrite I was researching. After all, manganese and zinc are cheap and have a wide range of applications. You guys are just lucky to have stumbled upon it, haha."

His boasting seemed perfectly plausible; otherwise, it wouldn't be easy to explain how he could immediately come up with a low-loss manganese-zinc ferrite process. No matter how impressive his claim, it's simply unbelievable that he could produce a process in such a short time, especially one with a loss rate drastically reduced to one-tenth.

Ah, Committee Member Gao has already studied it, then it's alright. Maybe he's already finished the experiment. After all, manganese-zinc ferrite is much simpler to obtain, and the materials and equipment he previously transferred from the Applied Chemistry Department should be able to complete this experiment.

"That's wonderful! Committee Member Gao, we are so grateful to you!" We never expected to stumble upon such a lucky break!

Gao Zhendong shook his head: "No need, please wait a moment."

He returned to his office, smoked a cigarette and rested for a while, taking up the time he spent "searching" for information before finally returning to the conference room.

The comrades have been eagerly anticipating this.

"Come on, comrades, take a look first. If there are any problems, let's discuss them."

The comrades were very considerate and gave this honor to the comrade from the Applied Chemistry Department. As mentioned earlier, radio frequency and electromagnetics were not very relevant to him, but this one happened to be right up his alley.

The material is not thick, only about four or five pages. This is the result after Gao Zhendong removed a large amount of patent terminology and repetitive content.

The comrades in the Applied Chemistry Department were overjoyed and read it carefully.

This process is very complete, from raw materials to sintering requirements. He was even confident that if he took this set of tools back, he could produce the materials described in it within a week.

Although it's unclear whether the material properties are as good as Committee Member Gao claims, the speed is certainly fast.

Besides, the materials that Committee Member Gao presented should be of high quality, especially considering how quickly he produced the first two materials. Although we don't know what they are, we can infer that they are at least more "advanced" than this one.

Look at this process. The proportions of Fe2O3, Mn3O4, and ZnO are clearly stated. Starting from the crushing of raw materials, the requirements for each step are clearly stated. Even the type of material used for crushing, the crushing time, and the crushing speed are all written down in detail.

She even considered how to achieve uniform granulation; she simply wouldn't believe it wasn't a mature process.

However, this thing doesn't seem to have much to do with chemistry. The whole process involves burning, crushing, mixing, crushing, and sintering... which made this expert in chemistry quite regretful.

There were even some things inside that he couldn't understand.

“高委员，这里面的Ta2O5、La2O3、CaTiO3这些东西是用来做什么的？”

Although the quantities of these things are small, only a fraction of a percent, they must be useful if they are added intentionally.

"Modification and treatment can increase the grain boundary resistivity at the grain boundaries of manganese-zinc ferrite, restrict grain growth, and thus reduce eddy current losses," Gao Zhendong answered logically, leaving his comrades completely captivated.

Crystals and grain boundaries—this is beyond the expertise of the other comrades present, including the one from the Applied Chemistry Department. These comrades don't really understand it, but Committee Member Gao explained it so clearly, it's obvious he's combining theory with practice. It seems this low-loss solution has a very good chance of success.

As expected of a master in materials science!
This is sure!

After the colleagues from the Applied Chemistry Department and Gao Zhendong finished reading the entire process document through question and answer, their confidence soared to the heavens. This was clearly the result of testing and was extremely reliable!

"Committee Member Gao, thank you so much! We'll go back and get to work, and get the ferrite device manufacturing process up and running!"

The ferrite type has been selected, and the manufacturing process for the ferrite blank has been obtained. We should hurry back and start the experiment. As long as the experiment shows that everything is not much different from what Committee Member Gao said, then at least the ferrite part itself can be considered done.

I came with a glimmer of hope, but unexpectedly left with a full load.

The amount of time and money saved is immeasurable.

Gao Zhendong laughed and said, "Have you finished designing the phase shifter?"

This was said to colleagues working in radio frequency.

"Not yet..." To be precise, progress is slow.

At this point, the RF engineers got a jolt of excitement.

Could it be that Committee Member Gao is willing to help? You know, this big shot has achieved great success in the field of radio frequency devices.

The domestically produced high-power traveling wave tube and planar slot antenna are all made by him.

As expected, Gao Zhendong lived up to their expectations and said with a smile, "Here's what we'll do: you go back and talk to the committee. If the committee agrees, send me a copy of the relevant materials, such as the phase shifter requirements, and I'll think about it for you later. But let me make it clear first, it might not be useful."

He wanted to get more detailed requirements, which required the committee's approval, even though he knew it was likely just a formality.

Without knowing their more specific requirements, Gao Zhendong couldn't proceed, and the pace of things also needed to appear more normal.

His smile seemed to glow in the eyes of his comrades.

Rationally speaking, it may not necessarily be useful, but judging from countless previous facts, it is unlikely to be useless; at the very least, it will definitely be helpful.

"Okay, okay, we'll go back and get the paperwork done at the committee right away," the colleague in charge of the phase shifter project assured them repeatedly. They knew very well that if they asked the committee for the necessary paperwork and provided the relevant materials to Committee Member Gao, the committee would absolutely give them the green light; there would be no other option.

This was one of the effects Venezuela wanted to achieve when they came here.

"Alright, then comrades, go to our branch factory canteen for a quick meal. I have other things to do here, so I won't keep you company."

Gao Zhendong's words made the comrades laugh. Committee Member Gao's words were certainly not an excuse, after all, the relevant personnel who were involved in his next matter had come with them.

"Oh dear, I'm so sorry, a few things got mixed up, I've kept you waiting." Gao Zhendong apologized to the colleague from the Institute of Applied Chemistry, who majored in polyacrylonitrile.

"No, no, it was our side that misunderstood the matter."

"Okay, fine, my apology is just a formality, haha. Let's get down to business. I'm considering using the PAN process to manufacture carbon fiber."

(End of this chapter)