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

The following morning, Wang Shouwu, dressed in a gray-blue woolen Zhongshan suit, walked into the Institute of Physics. His gaze, behind his gold-rimmed glasses, first swept over the visitor schedule handed to him by Huang Kun.

He was holding a thin leather notebook and a black fountain pen, while his assistant carried a stack of experimental reports with the edges of the papers tied with cloth strips and the covers labeled "Four-times Regional Purification Experiment".

Huang Kun shook hands with him, only saying that Furnace No. 3 was being kept warm, and then led his men through the corridor and directly pushed open the door to the furnace room.

After crossing the threshold, Wang Shouwu first looked at the furnace body. The ceramic protective sleeve of the double platinum resistance thermometer extended into the hot zone from the side of the sealed end cover, and the new copper nut and preload spring on the push box still had machining marks.

His gaze followed the sensor leads to the control panel, where the lead seal on the knob remained intact, and the scales for proportional, integral, and differential were all marked with the last set position.

Wang Shouwu reached out and held onto the edge of the control panel, followed the signal lines to find the two-stage DC amplifier, and then squatted down to examine how the grounding point was separated from the power line.

Huang Kun laid out the temperature control paper tape for two consecutive hours on the recording table, next to which were six regional purification curves, gas flow meters, and propulsion speed records.

Wang Shouwu looked at the 937-degree stable segment from the starting point of the paper tape. The black pen traced along the upper and lower limits and finally stopped on a set of fine, periodic ripples.

"How do you control amplifier drift?"

Jiang Ming opened the spare amplifier casing, revealing the pairs of resistors and calibration terminals inside.

"The input stage uses metal film resistors from the same batch for temperature compensation. After the amplifier is powered on, it is preheated and then zeroed using a standard resistor. During operation, it switches to the manual calibration terminal at fixed intervals."

Will the high-temperature calibration interrupt control?

"The calibration end only checks the zero-point offset, and the time is controlled within one mark on the recording paper. The actuator maintains the original output, and only switches to manual mode when the offset exceeds the specified value."

Wang Shouwu used a fountain pen to write down the interval between warm-up and calibration, and then moved the pen tip to that fine ripple.

"The fluctuation cycle here is consistent with the propulsion cycle, and the vibration of the transmission mechanism is transmitted to the sensor."

Fang Xudong pushed the feed paper tape below the temperature control curve. After the two time axes were aligned, the peak value of the fine wave fell exactly at the position where the screw completed a section of engagement.

Jiang Ming looked at the point of overlap and moved his finger along the curve through three cycles.

"The amplitude is about ±0.02 degrees. The impact of the regional purification stage on the length of the molten zone is within the measurement error. Single crystal growth is more sensitive to interface changes, and this vibration needs to be suppressed further."

Wang Shouwu separated the two curves and turned to the resistivity record after six rounds of purification. The problem then shifted from the control loop to the germanium material itself.

The curve in the first two-thirds has become flat, and the enrichment area at the tail drops rapidly in the last few sets of measuring points. The cut-off position is clearly marked with a red pencil.

His gaze lingered on the flat area for a long time before he put the pen in his palm and looked at Lin Lanying, who was standing on the other side of the record table.

What was the original purity of this batch of germanium materials?

"Two nines. Before going into the furnace, a retest was conducted. After six rounds, the first part reached three nines. The end and transition part were sealed separately."

Wang Shouwu gestured to his assistant to untie the cloth strip, pulled out a volume from the stack of reports, and turned to the resistivity curves of the four-zone purification process in his laboratory.

Within the same coordinate range, the curve continued to fluctuate, and the report sidebar stated that the furnace temperature fluctuated by two degrees, and the propulsion speed also shifted with manual pressure adjustment.

Huang Kun laid out the two records side by side. The difference in temperature control accuracy was directly reflected in the impurity redistribution results, and everyone in the furnace could clearly see the difference between the two curves.

Wang Shouwu asked about the purity of the protective gas, the cleaning method of the quartz boat, and the method of re-zeroing each time. Lin Lanying flipped through the process cards one by one, and her answers corresponded to the signed records.

"The closed-loop temperature control results are valid, and the data can be repeated six times. After the tail end is cut off, this batch of materials can enter the single crystal test."

After he finished speaking, he put his report back in his assistant's arms and turned his gaze to the cork box on the table.

Fang Xudong opened the box. The second single crystal, 32 millimeters long, was fixed in a cotton pad, with a polarizing microscope photograph and a resistivity curve measured along its length pressed next to it.

Wang Shouwu took out a handheld magnifying glass and looked at the end from the seed crystal connection point. The metallic gray side remained continuous, and the spacing of the growth traces was relatively uniform.

He then moved the microscope image to the window, where the continuous orientation ran through the entire cross-section, and the dispersed grains that had appeared in the first batch had disappeared in this sample.

"What parameters were used for this?"

"The rotation speed is 12 revolutions per minute, the lifting speed is 0.8 millimeters per minute, the melt temperature is maintained at around 945 degrees Celsius, and the total growth time is 40 minutes."

Wang Shouwu put down the magnifying glass and touched the end of the resistivity curve twice with the tip of his pen.

"The difference between the beginning and end is 30%, the segregation problem is still there. No matter how well the purification is done, the segregation coefficient cannot be controlled, and the resistivity of the single crystal is difficult to be uniform."

Jiang Ming placed his hand on the canvas bag buckle, but left the two pages of derivation for the time being, waiting for Wang Shouwu to continue asking questions.

"What you are using now is the equilibrium segregation coefficient from the literature. In the actual growth process, impurities will accumulate in front of the interface, and the melt flow will also change the transport rate."

Wang Shouwu picked up the photograph of the failed cross-section of the first furnace and put the milky white polycrystalline area and the rotational jamming record together.

"Changes in rotation speed will affect the temperature field, and changes in pulling speed will affect the interface overcooling. If either is over-adjusted, the resistivity will not be uniform before the crystal becomes polycrystalline."

Lin Lanying placed the foreign language literature she had compiled the previous night on the table. Several pages of it discussed the equilibrium segregation coefficient, but the experimental conditions differed significantly from those of the existing simple single crystal furnace.

Wang Shouwu turned two pages, closed his notebook, and turned to Huang Kun.

"The temperature control is indeed excellent, and the purification results have exceeded my expectations. However, the single crystal process is still at the first stage. The segregation coefficient involves melt convection, interface stability, and impurity transport, which cannot be covered by experience in electron tubes."

Wu Hanzhang stood by the door, turning the empty cigarette pack in his hand over, but ultimately leaving it in his palm.

Old Sun wiped the micrometer he had just used clean and put it back in the wooden box. Da Liu bent down to check the wiring on the control panel, while Fang Xudong stood guard by the recorder's table, waiting for Jiang Ming to speak.

Jiang Ming untied the canvas bag, took out the two pages of paper he had sorted out the night before, and placed Qian Xuesen's black lecture notes below the derivation page.

"I did a deduction on the issue of the segregation coefficient yesterday."

He walked to the blackboard in furnace room number three, first used the eraser to clear out a complete area, and then drew the outlines of the crucible, melt, and seed crystal in the center.

Wang Shouwu adjusted his glasses, reopened the thin-covered notebook in his hand, but remained standing, only pressing the black pen against the blank page.

Jiang Ming drew a narrow strip below the solid-liquid interface, with the chalk tip stopping at the δ position.