Chapter 1405 Subverted, but not by the way you think


    When Chang Haonan returned to the capital from Longyuan Province and saw the bizarre infrared emission spectrum, he was also a little surprised at the beginning.


    "Have you confirmed this result?"


    He asked Li Yabo, who was beside him with some conviction.


    The report from the Aeronautical Materials Institute was only five pages, but it had been in his hands for more than an hour.


    The edges of the paper were rubbed repeatedly and burped.


    Chang Haonan does not suspect that the subordinate units in the aviation industry system are engaged in data fraud, and even if it is fraudulent, it is impossible for him to take the initiative to deliver it to him.


    But this spectrum is really a coincidence.


    The low emissivity feature is almost strictly limited to the two atmospheric observation window bands. Not to mention detection, even if he gives a blank coordinate paper to draw casually, he will not dare to draw such a data curve.


    What''s even more bizarre is that the report also specifically states that the material of this sample was scraped directly from a turbofan 10G verification machine that completed its mission, and the technicians failed to reproduce the same result using the newly synthesized materials of the same model.


    It’s impossible to say what kind of holy land of turbofan 10G is, can you add BUFF to the materials?


    "Confirmed."


    Li Yabo took off his goggles and nodded:


    "Researcher Peng from the Institute of Aviation Materials reported the material last week. I have been repeating the tests before you came back. In general, although the reproducibility is not very good, there are still three replicates that basically consistent results. It can be considered that this material has extremely strong spectral selectivity under certain specific conditions..."


    Chang Haonan touched his chin, but did not ask too much about this reproducibility issue.


    The daily work of computational materials research is to design various strange and even synthetic material structures that may not be synthesized under actual conditions. It is normal for the same material to exhibit two or more different properties.


    "Specifically, what do specific conditions mean?"


    Faced with this problem, Li Yabo''s face showed a little embarrassment.


    But I still answered a long list like chanting scriptures:


    "When preparing samples, you must use a magnetron sputtering coating machine, and you cannot use an electron beam evaporation coating machine. The argon environment cannot last for too long, at most no more than half an hour. The heat treatment needs to be in a nitrogen environment, it cannot be a vacuum environment, and the substrate material cannot be processed with an ultrasonic cleaner and must be hand-washed..."


    “…Oh, in the process of preparing the periodic carbon array layer, you need to bring a can of ice cola and drink it all.”


    Chang Haonan''s pen tip suddenly poked a dot of ink on the paper.


    "ah?"


    He thought he had heard it wrong.


    "That''s right."


    Li Yabo confirmed very seriously:


    "And it must be Coca-Cola, nothing else can do."


    “…”


    Chang Haonan sighed, then nodded helplessly.


    He knew that people in fields such as experimental materials science or biology believe in some metaphysics. In fact, there was no sufficient sample size in just three experiments, which can basically be regarded as a coincidence.


    But no matter what, it is not bad to provide some emotional value.


    Besides, I just drank ice coke, and I had already respected materialism very much without adding any links such as kneeling instruments or jumping at the gods, so I didn''t go into it further:


    "Remember to ask Teacher Liu to reimburse the money you buy Coke in the future..."


    After a small episode, he picked up the report again.


    After all, there are still many doubts that have not been solved:


    "Did the materials you used for testing be synthesized by yourself according to the process mentioned in the attachment of the report, or were they scraped off from the turbofan 10G just like the Materials Research Institute?"


    "It''s synthesized by oneself..."


    Seeing his boss changing topics, Li Yabo finally breathed a sigh of relief and quickly replied: "Actually, I have studied it specifically. Finally, I found that the reason why Researcher Peng and others couldn''t reproduce the same results with new materials was because there was only an electron beam evaporation coating machine there, and then I discovered the first condition just now."


    Hearing this, Chang Haonan immediately sat upright and subconsciously muttered:


    "Can this turbofan 10G really buff?"


    Li Yabo is still recalling the details of his previous experiment, so naturally he didn''t hear such a small voice clearly:


    "Sorry...what did you say?"


    "Oh, nothing."


    Chang Haonan shook his head and began to analyze the situation in front of him:


    "Yabo, have you ever known about photonic crystals?"


    Li Yabo mainly studies metals and carbon-based materials, but he is not ignorant of the basic concepts in other directions.


    "I have heard that it seems to be an artificial material with periodic changes in dielectric constant. Due to the Bragg scattering effect, it can selectively control the propagation of light, which is a bit like the propagation ability of electrons in semiconductor materials..."


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    When he finished talking about this concept, he already understood what Chang Haonan meant:


    "You mean, is this coating material a photonic crystal?"


    But immediately doubted my judgment:


    "But the photonic crystals are basically non-metal-based materials, and they all have obvious multi-layer structures and artificial design traces. This coating material obviously does not meet the characteristics, right?"


    The so-called "artificial design traces" and artificial synthesis in general are not the same concept, but add artificial basic units to a large-scale level to form macro-equivalent media. At least at the current stage, it can basically be considered that mass production cannot be carried out.


    Chang Haonan waved his hand:


    "This metal-based coating obviously does not have the same macro structure as a photonic crystal, but the arrangement of microscopic particles may have certain similarities in a certain dimension."


    "You mentioned just now that the preparation of samples requires a magnetron sputtering coating machine to effectively observe the characteristic emission phenomenon. It is possible that the magnetic field has caused some changes in the microstructure of the material. This can also explain why this material has the same characteristics after evaporating the electron beam and evaporating it with the turbofan 10G after walking around."


    "In other words, it is not that the projects done by the 606 Institute and the Aeronautical Materials Institute were not comprehensive enough during the testing process, but that the materials themselves did not have such properties at that time..."


    Li Yabo''s eyes lit up when he heard this:


    "If so, maybe it is possible to try to use a means similar to the perturbation-dissipation theorem and Green''s function method to calculate the thermal emission level from a one-dimensional metal-dielectric periodic stacking structure, and then achieve the functional design of such... or such materials at a microscopic level?"


    "This is the principle, but at the algorithm level, there may be a lot of optimizations."


    Chang Haonan replied:


    "I will do this part of the work. You can verify my other conjecture first."


    Li Yabo, who was already ready to get up, sat back in his seat:


    "You said."


    "This material should be applied to the surface of the tail nozzle transition section, in other words, it is under the plasma, but it will still have an impact on infrared signal propagation in other directions... This is definitely not explained simply by low emissivity or strong absorption."


    Although Li Yabo is also a major in aviation, he has never been involved in aircraft design since he was studying for a doctorate, so he didn''t think about this at all.


    Now that Chang Haonan reminds me, I finally got back to my taste.


    "Then you mean..."


    Chang Haonan tapped his fingers twice on the desktop:


    "I suspect that this material may have a negative refractive index, resulting in the optical propagation path associated with it being completely different from that of the general media..."


    (End of this chapter)