I started with a ship full of max-level veterans, and I'm just a complete noob.

"First, let's look at the material conditions at the Institute of Physics. Once we have the isothermal region and impurity data, I'll provide you with the equipment plan."

Jiang Ming put away the graph paper, while Lao Sun had already placed the copper box on the corner of the table, the file marks on the lid still not completely smoothed out.

Three days later, Jiang Ming reported to the preparatory office of the Fifth Hospital in the west of the city. Just as the guidance materials were laid out, Qian Xuesen's secretary delivered an airmail envelope.

The cover bears the forwarding stamp of the International Exchange Office of the Chinese Academy of Sciences, and the upper right corner has a Pasadena postmark. The recipient's name was written by Theodore von Kármán.

The email was sent before Jiang Ming's first reply arrived in the United States. This was not a reply, but rather two technical communications that were en route at different times.

After checking the sealing wax, numbering, sealing, and signing, Jiang Ming recorded the receipt time and used a utility knife to open the short side.

The two pages of English letter contained no small talk; they began by pointing to the thermal protection of the hypersonic vehicle's leading edge stagnation zone.

Von Kármán inquired whether the ceramic insulation layer and the load-bearing frame could form a composite structure that combined insulation and load-bearing capacity, and attached the 1954 NACA report number.

The report recorded the temperature gradient in the stagnation zone, with the surface heat flux being much higher than that inside, and the elastic modulus and thermal conductivity of the material also changing with temperature.

The second page leaves only one question: after thermal conductivity becomes a nonlinear function of temperature, how should the heat transfer equation and the heat flow terms in the surface convection and radiation boundaries be rewritten?

There is another line of handwritten English in the footer.

*This is for Mr. Jiang specifically. Hsue-Shen mentioned your boundary-layer work, I would like to see how far you can push the thermal analogy.*

This letter was specifically given to Jiang Ming, as Theodore von Kármán wanted to see how far he could advance the boundary layer and heat transfer analogy.

Jiang Ming copied down the report number, his pen hovering between thermal conductivity and boundary heat flux.

In the stagnation zone, pneumatic heating increases with speed and density. While ceramics can provide insulation, the load-bearing frame will form thermal bridges, and the interface must also withstand expansion differences and thermal stress.

If thermal conductivity is treated as a constant, the equation is easy to solve, but the changes in the material after heating will be filled with errors.

Once written as a temperature function, internal heat transfer, surface convection, and radiation will be coupled, and the solution method must be changed accordingly.

Deep within my consciousness, the bronze pages turned on their own, their edges glowing with a warm bronze light.

[The conditions for deepening the study of Theodore von Kármán's academic achievements have been updated.]

The host must reply to a letter in their own name containing original technical viewpoints, and these viewpoints must be acknowledged and acknowledged by the recipient.

Current progress: 30%.

The first reply established a communication channel, and the new conditions required von Kármán to explicitly acknowledge Jiang Ming's views.

As the pen continued to move, the paper quickly showed three sets of variables: material thermal conductivity, surface heat flow, and load-bearing frame.

There were two knocks on the door, and Qian Xuesen came in carrying the overall design documents. He first checked the envelope number, and then looked at Theodore von Kármán's handwritten notes.

"The problem is only one page long, but it leads to a lot of other issues. You go first."

"Aerodynamic heating, nonlinear heat transfer, and thermal stress must be included in the same model; missile reentry cannot avoid these three factors."

Jiang Ming drew along the heat flow at the stagnation point into the interior of the material, and then added an interface between the ceramic layer and the metal skeleton.

"Thick ceramics are prone to cracking, and thermal bridges can form on the outer edge of the skeleton. The key is how to distribute the temperature difference and load at the interface."

Qian Xuesen circled the NACA report number and then pointed to the temperature function written by Jiang Ming.

"Mr. Feng is testing your ability to connect the boundary layer, heat transfer, and structure. You are to complete the reply independently; I will only review the format."

The pencil was placed back on the edge of the table, and Qian Xuesen did not touch the derivation part again.

"Write down to where you can prove it, but don't go beyond the experimental conditions. Mr. Feng can distinguish between derivation and assembly."

Jiang Ming locked the letters and report retrieval forms in the side cabinet.

Simply copying publicly available formulas will not gain recognition, while directly writing structural solutions that far exceed domestic material conditions will leave a gap in the source.

The European academic landscape had been opened up, allowing him to organize the boundary layer heating and similarity theories left by the Prandtl school and push them a step further from the then-public foundation.

This incision must also be able to be used for experiments.

Three more items were quickly added to the memo: temperature potential change, thermal resistance of the layered interface, and redistribution of thermal stress.

The most suitable approach to include in a reply is to rewrite the nonlinear heat conduction using a temperature potential into a form that is easy to solve, and then weaken the local thermal stress through a gradient interface.

Semiconductor research takes up 502 working days, and the Fifth Academy also needs to complete the demonstration of ground measurement chain and guidance predictor. The reply can only be verified between the two tasks.

That afternoon, right after the guidance interface meeting ended, Wu Hanzhang waited at the gate of the hospital with his temporary pass.

"The Institute of Physics held a briefing on semiconductor research and development. I was the only person on the original list, but I added you to the 502 Technology Group."

After handing the bicycle over to the guard for inspection, Wu Hanzhang patted the back seat.

"Get on board. The high-frequency band pre-research report has been registered, and the project number should be available in the next couple of days."

When the two arrived at the Institute of Physics, Chinese Academy of Sciences, there were already germanium ingot samples, spectral recordings, and prototype rectifiers on the table.

Huang Kun chaired the meeting, first writing the domestic progress on the blackboard, and then having the materials group report on the single crystal preparation status.

Existing processes can pull three germanium single crystals with a purity of nine, and some samples can be rectified and detected, but batch-to-batch differences cannot be suppressed.

When the resistivity curves of the three batches are superimposed, the carrier concentrations at the two ends of the same germanium rod differ by several times, and the deviation becomes even greater after temperature changes.

"The five nines are just a stage threshold for device testing. The laboratory should first strive for six nines. The types and distribution of key impurities need to be calculated separately."

Huang Kun wrote down two purity targets and then turned to the equipment list.

Regional purification relies on the difference in the segregation of impurities in the solid and liquid phases, allowing the narrow molten zone to move along the germanium rod and drive the impurities to the end.

The route was clear, but the experiment was stuck on the zone melting equipment.

The existing high-frequency furnace has an excessively wide hot zone, making it difficult to control the moving speed and temperature fluctuations. The Institute of Physics has modified two sets of equipment, but neither has been able to operate continuously.

The first set of coils heated up too quickly, causing polycrystalline growth in the middle section of the germanium rod. The second set of transmission mechanisms then sent the vibration into the molten zone.

When the width of the melting zone changes, the segregation conditions will also shift, and the purity after multiple meltings will actually be lower than that of a single melting.

Huang Kun unfolded the import equipment catalog, and both the zone furnace and precision temperature control components were on the embargo list.

"Put the imports aside for now. We'll handle the materials, germanium, and crucibles; the instruments, measurement; and the furnace, which we'll assemble ourselves, must be built by domestic companies."

Temperature records were pushed onto the table, and the curve fluctuated at intervals, with the maximum temperature difference exceeding one degree Celsius.

"The core temperature zone must be controlled within ±0.1 degree, and the germanium rod must not swing when it moves. Both of these must be done simultaneously."

Several research institutes subsequently reported thermocouples, voltage regulators, speed reduction mechanisms, and quartz tubes, and the blackboard was quickly filled with available components.

Individual components can be found, but when assembled into a continuously operating zone furnace, temperature feedback, coil thermal inertia, and mechanical vibration will restrain each other.

Jiang Ming opened the meeting materials, and the annotations in Lei Zhenbang's notes coincided with the equipment shortage.

Seven years ago, Lei Zhenbang stopped the high-frequency furnace at the temperature zone for too short a time and used too coarse temperature control.

Today, materials theory has focused on melting zone width, migration speed, and purity curves; what's truly lacking is a device that can operate stably for a long period.

After the meeting, Huang Kun, carrying the temperature record, chased after Wu Hanzhang in the corridor, stopped him as he was about to leave, and led the two back to the control panel.

"Old Wu, if 502 can make magnetrons, could you build us a zone melting furnace with a tolerance of ±0.1 degree? This has been a hurdle for almost a year."

Wu Hanzhang's hand, which was fastening the clasp of his briefcase, stopped. He turned to look at Jiang Ming.

Jiang Ming stood in front of the control panel, his gaze falling on the spread-out temperature curve. His fingers traced the ink lines, stopping at several sudden fluctuations.