Chapter 49
After passing through the initial and adjustment periods, the zero-gravity seat lab has been conducting experiments for several weeks. This Friday, the weekly workshop was held as scheduled, where several groups summarized the gains and losses of their experiments this week.
Gong Cheng's group was responsible for researching existing market materials. He opened his PowerPoint presentation to showcase the week's interim results:
"Based on the lightweight and high energy absorption characteristics of aluminum foam, we designed a composite structure consisting of three sets of aluminum foam, spring pad cores, and a metal skeleton. This structure provides strong support. Then, it is filled with polyester foam, and its softness and hardness can be controlled by adjusting the foaming agent and catalyst, resulting in a comfortable and durable product..."
The structural design diagrams shown in the PPT were very complex, including not only two-dimensional drawings, but also three-dimensional dynamic drawings when Gong Cheng talked about "continuous thickness variables and discrete material variables".
The members of other groups immediately perked up; they looked so professional. Their group's PPT was nowhere near as good. What could they do?
As Gong Cheng explained the PPT, he took in the expressions of the other group members, feeling a little smug.
He graduated from an engineering college and studied mechanical structure design and drafting, so he fully utilized his professional expertise when creating the PPT.
Of course, there was also a bit of showing off his skills, because he knew that these members could be eliminated by more professional researchers at any time, so he wanted to seize the opportunity to fully demonstrate his abilities at this seminar where everyone was present.
Having received positive feedback from the other group members, Gong Cheng dared to look at Ji Zhixing, only to see him slightly frowning.
Gong Cheng's heart skipped a beat. Was there something wrong with the structural diagram? He started to feel a little insecure. However, it was also possible that Ji Zhixing, being from the physics department, was having trouble understanding such complex structural diagrams?
Gong Cheng comforted himself with this thought, and then forced himself to continue analyzing their group's experimental plan for this week, trying to emphasize its advantages, but Ji Zhixing didn't smile at all from beginning to end.
After Gong Cheng finished speaking, he turned off the PowerPoint presentation, looked at Ji Zhixing, and waited for his comments.
Ji Zhixing began by praising, "Your group's structural drawings are very detailed. I noticed that you also conducted finite element simulations of three-point bending and axial compression of the infill structure, and conducted in-depth research on its bending and compression resistance. You've put a lot of effort into it!"
Gong Cheng's heart was stirred by the praise. He felt that there must be a twist in Ji Zhixing's story, and sure enough, he heard "but".
“However, the material structure is not ideal,” Ji Zhixing explained. “The pressure relief system itself is already complex enough, and the seat material should be as simple as possible. Even if it is a composite material, it is best to be integrated. This kind of material structure in which the four elements are mutually constrained will cause the system’s computational load to increase exponentially, directly leading to a significant increase in the failure rate.”
Gong Cheng was a little discouraged, so did his design concept go astray from the very beginning?
Ji Zhixing comforted him, saying, "Your drafting skills are very strong. When our project reaches Series A, B, and C funding rounds, we'll still need you to create the PPTs."
Just as clothes make the man and gold makes the Buddha, even the most technically sophisticated projects need to be presented through PowerPoint presentations when facing investment institutions. Especially since the decision-makers at investment institutions often don't understand the technology, the more detailed and complex the PowerPoint presentation, the more impressive it is, and the more it boosts the investment institution's confidence and valuation of their project.
Gong Cheng's eyes lit up. If he could follow the project to Series A, B, and C funding rounds, it meant that he was unlikely to be eliminated.
He had initially been worried that overly simple designs wouldn't showcase his professionalism, which was why he temporarily abandoned the one-piece material approach and opted for multi-structure materials. Now, reassured, he was fully energized and immediately began to consider the design concepts Ji Zhixing had just mentioned.
The second speaker was Yan Ru, whose group started their experiments from the "extremely soft" direction: "This week, our group experimented with several schemes, one of which is non-silicon-based mesoporous materials. When the pore size is controlled within 2-30nm, it has a high pore specific surface area and can exhibit good heat dissipation performance..."
At this point, everyone will smile knowingly. Who hasn't experienced the embarrassment of sweating or even getting heat rash from being stuck in a chair?
Especially during the summer of my senior year of high school, my butt and chair were practically inseparable from morning reading to evening self-study. Some students would place various cushions on their chairs to alleviate the heat and humidity. But in classrooms without air conditioning, the so-called "condensation" effect was often just better than nothing.
Therefore, in order to enhance user comfort, it is essential to quickly dissipate heat and prevent it from accumulating on the seat surface.
Yan Ru smiled slightly and continued, "However, this material also has a strong absorption capacity. If used as a chair surface material for a long time, it may store a lot of odors."
Odor? The first thing that came to Ji Zhixing's mind was the smell of sweat in the middle of summer, oh, and the smell of farts.
There are probably very few people in this world who don't sweat or fart. If the smell of sweat and farts is stored on the chair surface and cannot dissipate, how many people can remain unmoved by the stench? Therefore, this kind of material can only be eliminated.
"The second is acrylic resin. By adjusting the monomer dropping time, polymerization temperature, and material volume, the final form of this material is quite varied. It shows good compatibility with the pressure relief simulation system in the software, but its biggest drawback is its excessive hydrolytic performance."
Ji Zhixing asked, "Does sweat have any effect?"
"Yes." Yan Ru nodded. "Besides sweat, we also tried various beverages and drinking water, all of which caused varying degrees of corrosion to the materials."
They can't force users to not sweat or drink water while using the zero-gravity seat in the instruction manual, so this material has to be phased out.
Yan Ru continued clicking through the PowerPoint presentation to showcase her group's third proposal.
Zhang Yunshu silently admired Yan Ru, thinking, "She's amazing! She's completed three plans in just one week." She had been assigned to the pressure relief system team in the second phase, and had only just finished adjusting the response speed of the miniature cantilever beam sensor this week. It seemed she still needed to push herself a little harder.
Gong Cheng was also ashamed. His PPT was just showing off his skills, while Yan Ru's PPT, although it looked simple, contained real and substantial content.
When talking about the third option, Yan Ru's voice rose slightly. This was the material that their group was most satisfied with so far: "The third one is a coated metal nano-soft magnetic material with low coercivity and high saturation magnetic induction. I remember that one of the solutions for the pressure relief system was to use a composite magnetic buffer structure to support the resonant frequency of the human body. If we adopt this solution, then this material will be ideal, with high permeability and sensitive response."
Ji Zhixing glanced at the materials Yan Ru had submitted, which specified the numerical ranges for coercivity and saturation magnetic induction. He recalled the parameters of the composite magnetic buffer structure and said:
"This material can be further studied. Ideally, the coercivity should be controlled below 60 Oe, the saturation magnetic induction intensity should be increased to above 500 emu/g, and the remanence should be controlled below 20 emu/g. This is related to the oxidation rate, which will directly affect the durability."
Gong Cheng felt increasingly ashamed of himself. Ji Zhixing could casually propose technical standards for complex chemical materials; how could he not be knowledgeable in engineering design? He had just arrogantly thought he might not be able to understand structural diagrams…
Yan Ru jotted down the standards Ji Zhixing had mentioned on a piece of paper, but then frowned. How should they be adjusted?
They uniformly mixed soluble starch with a metal acetate solution, dried it, and then heat-treated it under N2 protection. After trying various ratios, the current structure and properties are already the optimal limit.
Seeing that she seemed clueless, Ji Zhixing remembered the book she had read last week and suggested, "Take a look at the book 'Preparation and Performance Study of Micro and Nanoparticles.' I remember it mentioned a solvothermal method. Co micro and nanoparticles prepared using this method have an additional layer of organic matter coating, and the particle size of the synthesized particles can be stabilized at around 5μm. The type of solvent, the amount of surfactant, the reaction temperature, and the time are all factors to consider."
Yan Ru suddenly understood: "Does the school library have this book?" If not, she would have to place an order as soon as possible.
"Yes," Ji Zhixing said casually. "It's on the third floor, on the top shelf of the fourth row of chemistry books. There's also a book on 'Thermal Stability of Inorganic Chemistry' on that shelf; you can take a look."
The members couldn't help but glance at him sideways. How many books and documents had Ji Zhixing read? And his memory was amazing! He knew exactly where each book was on the bookshelf!
Gong Cheng was inwardly moved to tears. This was true professionalism! It wasn't about making things complicated with fancy diagrams or diagrams, but about providing targeted advice on every aspect of the project.
Yi Deng from the "Hard" group also stepped forward to summarize the gains and losses of the week, but their group had not yet found any materials worth further study.
Finally, it was the decompression systems group's turn. This group has four members, and this week it was Jane's turn to speak on behalf of the group.
Jianxi wiped away sweat, opened the PowerPoint presentation, and wiped away sweat again.
Everyone laughed good-naturedly. This was Jianxi's first time speaking, so she must be a little nervous.
Jianxi chuckled and began to summarize: "This week we designed an adjustment component, which consists of a rotating shaft, a first coil spring, a second coil spring, a toothed component, and a bolt connection..."
Ji Zhixing listened and nodded. This part was basically about designing components based on their project theory and continuously testing the expression effect to achieve the best results. The coupling between the components was complex, but the direction was clear, and it wasn't difficult if you were careful and patient enough.
However, Jianxi pointed out the problem their group encountered this week: "This component works fine on its own, but when used with the decompression system in the simulation software, there is always a delay of 80-90 seconds."
"The lag is that severe?" Ji Zhixing was a little surprised.
The lag translates to an extremely dull zero-gravity effect for the user. From the moment you sit down, it takes a full 80-90 seconds to feel the zero-gravity effect.
Moreover, it's impossible for most people to maintain the same posture without moving for an extended period while sitting in a chair. Even a slight adjustment in posture or a slight shift in the center of gravity requires waiting for a full 80-90 seconds, which is definitely a terrible experience.
Just like mobile apps and computer software, a response time exceeding 2 seconds is enough to make most users dissatisfied, anxious, or even irritable. Therefore, in recent years, major mobile phone manufacturers have been striving to improve system response speed to optimize the user experience.
According to their original design and the smooth-running simulation system, the zero-gravity effect should be instantaneous and rapid. If this cannot be achieved, then the product is essentially a failure.
Ji Zhixing looked at Lin Lang, who nodded. He knew that although Lin Lang often messed up in daily life, he was very serious when it came to important matters. Moreover, after a long period of intensive study before and after the competition, Lin Lang's professional skills had also greatly improved.
Therefore, before Lin Lang asked for help, Ji Zhixing decided not to intervene and let Lin Lang lead the stress relief team to solve the problem himself.
After some time, the materials team had experimented with several specific and feasible rough solutions, and the pressure relief team had also designed corresponding components based on the possibilities simulated in the first stage. However, none of the components could completely solve the hysteresis problem, and the optimal solution could only reduce the hysteresis to 65 seconds.
Lin Lang was so anxious that he went bald, so he asked Ji Zhixing to intervene in their group's research.
Ji Zhixing reviewed all the components designed by the stress relief team from beginning to end, but still couldn't find the problem, so he had to continue trying to optimize the local parts.
"A damping rack is installed on the guide rail at the bottom of the lower guide column, and a damping gear that meshes with it is fixed along the guide rail..." Ji Zhixing said as he adjusted it himself. After adjusting it, he connected it to the electromagnetic unit, and it ran well.
"Next, let's try it with the simulation software." Ji Zhixing set up the components next to the computer.
Jianxi said, "I'll do it." He reached out and gathered all the component control wires together, deftly connecting each of the 18 wires to the computer simulator.
Ji Zhixing squatted down to confirm the coupling between the components once again. Before long, Jian Xi had already entered the specific parameters into the simulator.
Five or six people stood around the computer, their hearts pounding. The simulation system had already begun applying 50kg of pressure, but the components remained motionless. After 61 seconds, the components seemed to finally react and start operating.
"It still doesn't work..." This was the first time Ji Zhixing had felt so frustrated since he started preparing for the CUPT competition. He had checked every step of the process repeatedly, but the results were still unsatisfactory.
Could it be...? Ji Zhixing lowered his head in deep thought. Could it be that there was a problem with their theory itself? After thinking it over, this was probably the only possibility.
When they first participated in the competition, some judges objected to their project theory, believing that they shouldn't apply the Navier-Stokes equations to a non-fluid project. However, they used various initial conditions, boundary conditions, and environmental conditions to constrain the Navier-Stokes equations, which theoretically made them sound, and this was recognized by Professor Wen Zhengyang, the chairman of the judging committee, and others.
But what if their theory actually contains a bug in some part that even the judges haven't noticed? Or what if the various restrictions they imposed on the Navier-Stokes equations just happen to cause an unprecedented malfunction in the Navier-Stokes equations?
Ji Zhixing has started spending time in the library again. He has read almost all the books related to the Navier-Stokes equations, and now he needs to supplement his reading with the latest papers.
"Principles of Solving Navier-Stokes Equations by Finite Difference Method", "Compatibility Phenomenon of Initial Values and Boundary Conditions of Navier-Stokes Equations", "Analysis of the Solution Space and Regularity of Navier-Stokes Equations"... He now reads quickly and remembers well. In three or four days, he read through all the cutting-edge research on Navier-Stokes equations and memorized them.
Then Ji Zhixing began to work out the ideas on his notebook.
Boundary conditions...
Viscous flow under dynamic conditions...
Parallel flow under gravity...
Stokes' first question...
While Ji Zhixing was racking his brains in the library, the others in the lab were also continuing their experiments.
Jianxi looked around. Lin Lang had been called away by Xu Dongyang to help with material procurement, so neither of them were there. He gently nudged Zhang Yunshu beside him with his elbow and whispered, "What do you think... is it going to work?"
"What do you mean, 'can it or can't it'?" Zhang Yunshu asked, her face full of confusion.
“It’s their theory!” Jianxi said with a worried look. “Our current experiments are all based on their project papers. If their theoretical basis is flawed, then haven’t we been working on this for the past six months without any progress?”
"Probably not." Zhang Yunshu had never thought of this. "Their project won first prize in the CUPT competition, so the judges must have looked at it carefully. I heard that Professor Wen Zhengyang was one of them. If there were any problems, surely he would have noticed them too."
"Well, it's hard to say... Actually... never mind, I won't say anymore..." Jian Xi stammered, glancing at Zhang Yunshu.
Zhang Yunshu was exasperated. Why not just say what you want to say? She didn't tolerate being chased around like that. She reached for two baffle-lock valves on the materials shelf. She'd rather use this time to design a new set of components.
Jianxi found it strange that she wasn't cooperating at all. Aren't girls supposed to love gossip? Why isn't she asking?
After waiting a while longer, seeing that Zhang Yunshu really didn't seem curious at all, Jian Xi was about to speak when Gong Cheng walked up to him with a piece of polyethylene fiber in his hand.
"Jianxi, move aside, I need to test this material." Jianxi blocked the transmission electron microscope sample stress meter.
"Okay." Jian Xi stepped aside and looked at Gong Cheng, saying, "It must have taken a lot of effort to make such a small piece, right?"
"Yes." Gong Cheng didn't say much, his eyes fixed on the stress meter screen.
"Sigh, I don't even know if all our efforts were worthwhile," Jianxi sighed from the side.
Gong Cheng sensed a hidden meaning in his words and couldn't help but ask, "What do you mean?"
“Well…” Jianxi looked around again, making sure Lin Lang and Xu Dongyang hadn’t returned yet, before whispering, “I heard that several judges in the CUPT competition are Professor Yan’s old classmates and friends…”
Gong Cheng didn't understand why Jian Xi suddenly brought this up, and asked, "And then?"
"Why is this guy so slow?" Jianxi glared at him, then made her point more clearly: "Exactly, back then they won first prize, didn't they..."
Gong Cheng then realized: "You suspect they got in through Professor Yan's connections?"
Damn it! Couldn't you have kept your voice down? But everyone was already looking over because of Gong Cheng's completely uncontrolled remark.
Yi Deng asked seriously, "Jian Xi, is that what you mean?"
"No! No!" Jianxi hurriedly shook her head. "I was just thinking that they only had two months to prepare for the competition. Could there be some theoretical lapses..."
Zhang Yunshu rolled her eyes. Didn't this mean she was still questioning the legitimacy of Ji Zhixing and his team winning the first prize?
She said, "Including Professor Wen Zhengyang, aren't all 12 competition judges giants in the field of physics? Is it really necessary to ruin one's reputation for a college student competition?"
"Sigh, you misunderstood me." Jian Xi looked at Zhang Yunshu with a "how could you be so unreasonable?" expression. "What I meant was, even if the zero-gravity seat project won first prize, it doesn't mean it's perfect, right?"
Jianxi looked around, spread her hands, and said, "What if their theory happens to have a bug in a very important part, making it impossible to support practical application? Wouldn't all our hard work these past few days be wasted? Can you honestly say you haven't been worried at all?"
Everyone in the lab fell silent. How could they not have been worried?
When I saw the recruitment post and became interested in Zero Gravity Club, I was already worried for a while. But after careful consideration, we decided to trust Ji Zhixing's abilities and the authority of the CUPT competition first prize, so we put aside our concerns and joined Zero Gravity Club.
The decompression team's experiments have been stalled for the past few days, unable to break through the bottleneck. Everyone has been worried, but it's not time to doubt the correctness of the theory so quickly.
Yan Ru was the first to speak: "I believe in the president's abilities, and I also believe in the fairness and authority of the CUPT competition." Then she continued with her experiment.
Yi Deng spoke second: "How long has the formal experiment been going? Just over a month. The fact that your group's experiment didn't go smoothly doesn't necessarily mean there's a problem with the theory. Besides, hasn't the club president been reviewing and verifying these past few days?"
Others chimed in, but Jianxi remained disheartened: "When will we get there?"
"Right now!" Ji Zhixing's voice came from the doorway.
Jianxi shuddered. He was so embarrassed to be caught talking about someone behind their back that he wished he could dig a hole and disappear right there.
Ji Zhixing walked in carrying a stack of papers, glanced at Jian Xi calmly, and didn't say anything more.
He asked Zhang Yunshu, "What about that component with the damping rack and gear that we adjusted last time?"
“It’s in the warehouse,” Zhang Yunshu replied.
Ji Zhixing followed Zhang Yunshu to the warehouse, retrieved the component, set it up next to the computer, and began connecting the control cable.
"Let me do it, I'm faster." Jianxi reached out to grab the control line.
Ji Zhixing held the thread away from his hand, her voice indifferent: "No need, I can do it."
Sweat streamed down Jianxi's face. Seeing that Ji Zhixing was almost finished connecting the wires, he stood in front of the computer waiting to input the parameters.
Ji Zhixing said without even looking up, "Don't move, I'll type it in myself in a bit."
Everyone looked at each other in bewilderment. Was the club president angry?
“Uh…” Jianxi stood in front of the computer, extremely embarrassed. “I’m sorry, President, I really didn’t mean anything by it. I was just too anxious. You know my family has been urging me to prepare for the postgraduate entrance exam. I just wanted to get results quickly so they wouldn’t worry…”
That's true. Jianxi's family has been calling him almost every day these days. Although he answers the calls in the corridor outside the lab, everyone in the lab can hear what he's saying.
"Really?" Ji Zhixing finished connecting the wire and looked at Jian Xi seriously. "Let's talk about the rest later. Please step aside for a moment."
Jianxi gripped the keyboard tightly, pleading, "President, please give me another chance!" Tears were welling up in her eyes.
In the lab, some people thought Jianxi was being too pretentious, while others felt that Ji Zhixing was a bit cold-hearted.
Ji Zhixing looked Jian Xi straight in the eye and said calmly, "I've reviewed all the steps these past few days. The theory is fine, the simulation software is fine, and the components are fine. So, where could the problem lie?"
Jianxi panicked and dared not look Ji Zhixing in the eye: "I...I don't know..."
Yan Ru stood behind Jian Xi and saw that his back was soaked with sweat. Was he really that nervous? Could it be...?
Yi Deng also had a guess in his mind: the theory, simulation software, and components were all fine, so the problem must lie in the intermediate steps. And the intermediate steps... it seemed that Jian Xi had been handling the wiring and input parameters all along?
The others in the lab gradually realized what was happening and watched Jianxi's overly nervous reaction with cold eyes.
Ignoring Jian Xi's pleas, Ji Zhixing pushed him away. Although Jian Xi tried his best to stand firmly, as if rooted to the ground, Ji Zhixing, having been thoroughly trained in the system space, managed to push him aside.
Yi Deng stepped forward and stood next to Jian Xi, secretly guarding against him doing anything irrational.
Ji Zhixing then stopped looking at him, turned around and entered 18 sets of parameters into the simulation software, and started the simulation software.
The components start operating the moment the simulation software begins to release the pressure.
"We did it!" Zhang Yunshu exclaimed in delight.
Ji Zhixing continued to adjust the pressure data to simulate the weight changes caused by the adjustment of human sitting posture, and the components responded very sensitively and quickly.
Everyone in the lab cheered, except for Ji Zhixing and Jian Xi.
Ji Zhixing shut down the simulation system, turned to look at Jian Xi, who was covered in cold sweat, and said, "Fan Chuanshuo's other graduate student spot was reserved for you, wasn't it?"
A note from the author:
The solution to Fan Chuanshuo's problem will likely be resolved within two chapters.
The description of "nano-soft magnetic materials" in this article refers to "Preparation and Performance Characterization of Coated Metal Nano-Soft Magnetic Particles", Classification No.: TB383.1;
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