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

"Let's go to the Institute of Physics and let Huang Kun see for himself."

Before Wu Hanzhang's voice could be heard as the car door closed, the jeep drove along the stone-paved road outside the factory area toward the west of the city.

At nine o'clock in the morning, as soon as the window of the office of the Institute of Physics was opened, the resistivity report of the previous batch of samples was already laid out on Huang Kun's desk.

Wu Hanzhang placed the canvas bag on the table, took out the twelve-page proposal, and arranged them according to the page numbers.

"Please take a look at the temperature control system first."

Huang Kun didn't respond. He picked up the first page and began reading from the differential structure of the double platinum resistor.

Lin Lanying stood at the office door, holding three resistivity curves in her hand, her gaze falling on the paper over Huang Kun's shoulder.

Jiang Ming sat at the side of the table, waiting for them to turn the page.

The first eight pages describe the temperature measurement accuracy.

Jiang Ming divided the temperature coefficient of the platinum resistance thermometer into three sections: calibration zone, working zone, and correction zone. He also listed the calculation process for the imbalance sensitivity of the Wheatstone bridge, and noted the gain, noise ratio, and zero drift of the two-stage DC amplifier.

Huang Kun moved his pencil along the edge of the page, tapping on key numbers as he went. When he saw the shielding method of the sensor leads, he turned back to the previous page to check the bridge structure.

The only sound in the office was the rustling of papers.

Jiang Ming watched the pencil move back and forth along the edge of the page, his gaze always following the formulas, refusing to look at the report in Lin Lanying's hand.

Pages nine through eleven contain the control loop.

Huang Kun lingered for a long time beside the step response method, then reached out and picked up the Soviet-translated book on the principles of automatic regulation from the corner of the table.

The edges of the pages were worn white. He turned to the chapter on proportional, integral, and differential adjustment and compared it with the parameter definitions in the recommendation book item by item.

"Does the critical gain here refer to the boundary value before sustained oscillation begins?"

"right."

Jiang Ming answered.

"First disconnect the integral and differential, only increase the proportional term, record the temperature curve, and wait for the oscillation to reach a stable amplitude before converting the three parameters according to the period."

Huang Kun raised his eyes.

"The furnace temperature is oscillating continuously, and the germanium material is already inside. How can we ensure the sample won't be burned?"

"The time constant was measured without a load the first time, a quartz tube was installed the second time, and a germanium rod was added the third time. The parameters converged step by step."

Jiang Ming pointed to page eleven.

"Each level has a set temperature limit and a manual power-off position. If the test curve exceeds the range, immediately switch to manual mode."

Huang Kun lowered his head again and drew a circle next to that line with the tip of his pencil.

Page 12 is about nonlinear correction.

Below the quadratic polynomial compensation formula, Jiang Ming listed the calibration points and fitting intervals for the high-temperature section. To the right, there is an upward-curving curve, whose fluctuations show the same trend as the previous batch of carbon rod furnace records.

Lin Lanying took two steps closer from the door and placed the report in her hand on the corner of Huang Kun's desk.

"This slope."

She pointed to the compensation curve on the proposal and then opened last year's record.

"When we tested the carbon rod furnace, we measured the offset from 900 to 950 degrees. Although the data points were scattered, the slope matched this graph."

Huang Kun put the two sheets of paper together.

Lin Lanying looked up at Jiang Ming, the polite distance from before had changed, her gaze lingered on his face, and then returned to the paper.

Have you performed high-temperature platinum resistance calibration?

"We have reviewed the high-temperature measurement records, but the specific calibration will need to be redone based on your samples."

"In which unit is the record kept?"

"The documents are scattered throughout the factory, and the equipment conditions are different, so they cannot be directly moved and used."

Jiang Ming stopped there.

Huang Kun closed the proposal and placed his hands flat on the paper.

"Theoretically self-consistent."

He pressed a crease along the edge of the cover with his fingertip.

"Whether the positive and negative zero points can be reached by one degree depends on the amplifier's zero drift and the reproducibility of the platinum resistance thermometer. You have experience with vacuum tube amplification in the 502, and for the latter, you need to use a calibrated industrial platinum resistance thermometer."

Lin Lanying put the failed sample report back into her arms.

"The resistivity issue is still a problem; temperature control is just the entry point for the furnace."

"So we'll start with temperature control."

Wu Hanzhang leaned against the table.

"Once the furnace is stable, we can then test the purity and propulsion separately."

Huang Kun picked up the proposal and flipped to the PID tuning section.

"I have a question."

Jiang Ming looked up at him.

"I haven't seen the parameter formula for the step response method in any publicly available Chinese textbooks. The Soviet translation only mentions the name, but doesn't give the relationship you wrote."

Someone passed by outside the office door, and the footsteps quickly faded away.

Huang Kun pushed the book on the principles of automatic adjustment in front of Jiang Ming.

"Where is the source?"

Jiang Ming opened the canvas bag, took out Qian Xuesen's black lecture notes, and turned to the last two pages of the chapter on automatic control.

"Mr. Qian left an entry point for engineering simplification in his lecture notes. There are several English journal indexes in the archives. I looked them up in that direction and filled in the adjustment process myself."

Huang Kun took the lecture notes, read the first half-page, and then looked at the densely packed calculations on the proposal.

"Is the complete formula in the index?"

"The index only lists the article title and author; you need to search for the specific content using keywords."

Have you read the original text?

"After reviewing the relevant table of contents and abstracts, the remaining part was derived by combining the thermal inertia of the furnace."

Jiang Ming didn't finish his sentence, pressing his finger down on the corner of the handout to prevent the paper from curling up.

Huang Kun looked at him for a few seconds, then stood up and opened the office door.

"Comrade Lin Lanying, please vacate furnace position number three next Monday."

Lin Lanying responded, but first glanced at Jiang Ming.

Huang Kun continued, "To work with the 502 thermostat, we'll install a temperature control system. First, we'll conduct an unloaded test. If the temperature can be locked within ±0.5 degrees Celsius, then we can discuss the next steps."

Wu Hanzhang asked, "What about the germanium?"

"After passing the no-load test, a small amount of waste material is placed first to confirm the atmosphere and sensor readings before the formal sample is introduced."

"How long will it take?"

"Let's see how fast they install it."

Huang Kun closed the automatic adjustment mechanism and placed it back on the corner of the table.

"±0.5 degrees is just the first barrier. Between ±0.1 degrees and it, there are amplifiers, sensors, actuators and the thermal inertia of the entire furnace."

His gaze fell on Jiang Ming.

"Young people have some skills. Before the actual curve is released, the numbers can only be considered suggestions."

"I'll bring people to meet your standards."

Jiang Ming put away the black lecture notes.

"Submit the no-load curve next Monday."

Huang Kun nodded, and Lin Lanying pulled out the duty roster for Furnace No. 3 and wrote "502 Technical Group" in the Monday column.

On the way back to the factory, Wu Hanzhang sat in the back seat of the jeep and lit a Daqianmen cigarette.

The smoke slowly drifted down the roof of the car. He tucked the cigarette behind his ear and pressed his palm against the twelve-page proposal in his canvas bag.

"Old Huang gave us half a door."

Jiang Ming sat in the passenger seat, flipping through the records of the No. 3 furnace from the Institute of Physics.

"What do you plan to use to break open the other half of the door?"

"The actual object."

Jiang Ming turned to the last page of the record.

"Within a week, let him see a control curve of plus or minus 0.1 degrees."

Wu Hanzhang looked at the back of his head.

"Idle?"

"Real working conditions with germanium rods."

The wheels rolled over the tracks at the intersection, causing the carriage to sway slightly, and the record sheet in Jiang Ming's hand slipped down to his knees.

"The no-load curve can only prove that the circuit is active. After the germanium rod is installed in the molten zone, the parameters of thermal inertia, heat dissipation and propulsion speed will be changed. The real acceptance test must be carried out under load conditions."

Wu Hanzhang took the cigarette from behind his ear and tucked it between his fingers.

"Old Sun, Fang Xudong, Da Liu, plus you, are four of us enough?"

That's enough.

Jiang Ming wrote the test sequence of the time constant of Furnace No. 3 on the back of the paper.

"Old Sun modified the transmission and furnace body, Fang Xudong oversaw the measurement and recording, Da Liu was in charge of processing and wiring, and I worked on the control circuit."

Wu Hanzhang exhaled a puff of smoke.

"The people at the Institute of Physics might not be willing to let you dismantle the furnace."

"They'll look at the curve first."

"What if the curve doesn't appear?"

Jiang Ming circled the last item on the back of the paper.

"Then let's start over with the threshold of plus or minus 0.5 degrees until Furnace No. 3 gives up its time constant."

The jeep drove into the Third Electronics Factory, and Wu Hanzhang stubbed out his cigarette before the door opened.

"Go to Workshop No. 1 to find Lao Sun tomorrow morning."

"I also want to call him Fang Xudong."

"He's waiting for you in room 502."

When Jiang Ming got off the bus, the proposal in the canvas bag had already been handed over to Wu Hanzhang for safekeeping. He only had the No. 3 furnace record and a redrawn test procedure in his hand.

The Institute of Physics provided a one-week timetable, and the resistance of Furnace No. 3 was based on a real piece of equipment.

That night, Jiang Ming divided the blackboard in Lab 502 into four columns: sensor calibration, amplifier zero drift, actuator response, and germanium rod load.

He had just finished writing the last column when Old Sun poked his head in from outside the door.

"Professor Jiang, when you arrive at the Institute of Physics on Monday, shall we dismantle the furnace first?"

"Test first, then disassemble."

Jiang Ming spread out the structural diagram of Furnace No. 3, his finger landing on the transmission frame below the quartz tube.

"Temperature, pyrometer readings, heating current, and propulsion speed should all be aligned to the same timeline. No one should touch the heating circuit until the original curve is obtained."

Old Sun glanced at the blueprints and then reached out to push the door open.

"Understood. I'll go and call Fang and Da Liu, and also get all the tools and spare parts ready."

"Go directly to the Institute of Physics on Monday morning."

Jiang Ming lowered his head and finished filling in the last time point on the process sheet, the pencil line running across the old record of Furnace No. 3.

To find out exactly where the No. 3 furnace is slow, we'll have to wait for Monday's curve to reveal the answer.