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

Pushing open the side door of Workshop No. 1, the residual heat from the heating pipes rushed towards you.

Jiang Ming placed the enamel basin on the corner of the workbench. The steamed bun went cold after he took two bites, and the cabbage soup was barely touched.

He picked up the brown glass bottle next to him and shook it in the light.

The bottle contains the standard solution that Xiao Zhao prepared yesterday afternoon. The calcium carbonate powder was dissolved in hydrochloric acid and then diluted to 500 ml, which is equivalent to 10 mg of calcium ions per liter.

"Is the EDTA ready?"

Xiao Zhao took out a conical flask from the cabinet. There was a handwritten label on the flask, and the ink was not yet dry.

"It was prepared last night, at 0.01 mol/L. The Chrome Black T indicator is also ready, but the color is as dark as soy sauce."

"Enough."

Jiang Ming removed the glass receiving bottle below the copper water jet outlet. The bottle contained about 300 milliliters of clear liquid, and no suspended particles could be seen when held up to the light.

He used a pipette to draw 50 ml of the effluent sample, poured it into a clean conical flask, added two drops of ammonia buffer to adjust the pH to around 10, and then used a spatula to sprinkle in a small amount of Chrome Black T powder.

The solution immediately turned wine red.

"Watch closely."

Jiang Ming held the conical flask with his left hand and unscrewed the stopper of the burette with his right hand, letting the EDTA solution drip down one drop at a time.

Old Sun and Da Liu also came over, and the three of them squeezed together, staring at the wine-red liquid in the conical flask.

The color did not change when the first drop of EDTA was added.

The second and third drops were still wine-red.

Jiang Ming closed the stopcock completely, picked up the conical flask, and gently shook it a few times.

The solution color changed from wine red to pure blue, with a clean transition and no pink intermediate state.

"It changed color after using almost no product?"

Xiao Zhao leaned over to check the graduations on the burette; the liquid level had barely dropped.

"This indicates that the concentration of free calcium ions in the effluent is lower than the equivalent of one drop of EDTA."

Jiang Ming placed the conical flask back on the table; its blue color shone brightly under the light.

"Converted, the calcium hardness is far below 0.5 ppm, which is below the detection limit."

Old Sun rubbed the rust on his hands and grinned.

"So, does that mean our copper pipe is now standing?"

"It's standing firm."

Without further ado, Jiang Ming turned around, pulled over the binder of the process report, flipped to the twentieth blank page, and began writing directly on it with his pen.

Calibration procedure for deionized water column exchange capacity.

Every 48 hours, 50 ml of water sample was taken and the calcium ion concentration was determined by EDTA complexometric titration.

The indicator is Chrome Black T, and the endpoint color changes from burgundy to pure blue.

When the calcium hardness of the effluent exceeds 0.5 ppm, the packing material is considered to be close to saturation, and the activated carbon layer and sulfonated coal layer must be replaced immediately.

After he finished writing, he looked up at Xiao Zhao.

"Copy it into the duty log, put it on the same page as the instrument calibration, and sign and date each calibration result."

Xiao Zhao took the report, glanced through it, and nodded in agreement.

Da Liu was already squatting in front of the row of metal cabinets in the corner, rummaging through spare fillers.

He moved three sealed jars out and placed them on the ground. The largest one contained acid-washed hardwood activated carbon, the middle one contained sulfonated anthracite, and the smallest one contained degreased cotton.

"Divide into three portions according to the proportion of column number one, each portion is enough for one replacement."

Jiang Ming added a sentence.

Da Liu gave him a knowing gesture and began dispensing the materials into the spare container.

Jiang Ming stood there, looking at the makeshift pure water production line that had been converted from a boiler room steam pipe, and mentally reviewed the entire process.

Distillation and condensation supply raw water, copper water column for deep desalination, glass column for compensation backup, calcium carbonate standard solution for failure warning, and spare packing material to ensure replacement within four hours.

Water production, calibration, early warning, replacement.

It's a closed loop.

……

The door to the isolation room in the security department was locked from the outside, and the windows were covered with newspapers, leaving only a crack to let in the gray daylight.

Liu Shouxin has been sitting on that hard bench for almost two months. He has lost weight, his cheekbones have become more prominent, and a few strands of stubble have turned white on his chin.

When Director Wang pushed open the door, he didn't bring his file folder. He sat down opposite him empty-handed, put his enamel mug on the table, and the lid of the mug made a loud clatter.

"Comrade Shouxin".

When Director Wang spoke, his tone was slightly more relaxed than usual.

"The Lunar New Year is approaching, and my family has asked around twice already."

Liu Shouxin didn't reply, his eyes fixed on the shallow groove on the table.

"You know that receptionist in the eastern suburbs, her surname is Zhao, right?"

Liu Shouxin's shoulder twitched slightly, but the movement was very small.

"He confessed last week."

Director Wang picked up his enamel mug, took a sip of tea, and spoke in a calm and unhurried manner.

"At 2:17 PM on September 14th, at 9:43 AM on September 16th, and at 4:02 PM on September 18th, there were three phone calls, all from our factory's gatehouse to the East Suburbs gatehouse."

"Handwriting analysis confirms you are the signatory."

Liu Shouxin's Adam's apple bobbed, and his lips pressed into a thin line.

Director Wang didn't press further; he simply put down the enamel mug and leaned back in his chair.

The silence lasted for about two minutes.

"I don't know what's in the bucket."

Liu Shouxin spoke, his voice hoarse.

"Where's the note?"

Liu Shouxin glanced at Director Wang, then quickly lowered his head again.

"In early September, a note was found tucked into the factory's mail exchange pouch. It was unsigned and contained only one line of text."

"Collect three buckets of slag on the 17th and place them at the base of the east wall of the sand-making plant."

"Who put it there?"

"have no idea."

Director Wang did not ask any further questions.

He stood up, picked up the enamel mug, and paused at the door.

"You know how many people the exchange envelopes pass through each day."

"Think it through before you talk to me."

The door was locked again from the outside, and the sound of the key turning echoed in the hallway before quickly falling silent.

……

The flat-headed clerk was already waiting in the next room. On the table was a thick register with the cover printed with "Internal Exchange Mail Records of the Third Electronics Factory".

"All of September's are here."

The clerk patted the notebook.

"Every letter exchanged into the factory mailroom must be registered with the sender and recipient, and the same applies to letters leaving the factory."

"If the note was tucked inside the mailbag, the sender may not be the real sender, but the postal clerk who handles the sorting can check it."

Director Wang turned to the page from September 1st, which was covered with dense blue ink pen writing, one record per line.

"Daily comparison."

"Focus on whether there are any unidentified packages or envelopes with registered addresses that do not match the actual contents, sent between September 1st and September 5th."

"clear."

"There's one more thing."

Director Wang closed the register and pushed it back.

"The code name 'Grey Pigeon' indicates access to the factory's mail circulation process. It means either factory personnel or outsiders can regularly enter the factory to deliver mail."

"Please also pull up the list of all external personnel who delivered parts to the factory in September."

The clerk tucked the register under his arm and quickly went out the door.

……

The evening wind was colder than yesterday, and a thin layer of frost had formed on the metal exterior wall of Workshop No. 1.

Jiang Ming is checking the readings for the 396th hour at the testing station.

The pointer on the five-tube microammeter is very stable, with no visible change compared to yesterday.

He copied the numbers one by one onto the graph paper, the pen tip making a soft sound as it traced the lines on the paper.

Wu Hanzhang pushed open the side door of the workshop and came in, his body radiating coldness, clutching a piece of telephone record paper in his hand.

"This is an encrypted call from Fengtai marshalling yard."

He handed the paper over.

Jiang Ming took it and glanced at it.

The military train's freight cars have passed Shijiazhuang and are expected to arrive in Fengtai before 2 p.m. tomorrow.

"How are the pick-up arrangements?"

"The Chinese Academy of Sciences will send someone, surnamed Fang, from the microwave group of the Institute of Physics."

Wu Hanzhang rubbed his ears, which were red from the cold.

"In our factory, the ministry specifically requested your name, and I'll be in charge of administrative coordination."

"We'll leave tomorrow at noon; the factory's jeep can run it."

Jiang Ming folded the phone record sheet in half, stuffed it into his shirt pocket, and glanced down at the five tubes emitting a dark red light on the testing table.

"Old Sun."

"exist."

Old Sun poked his head out from under the platform.

"I won't be at the factory tomorrow afternoon. The B-type pipe will be ready at 420 hours. Keep an eye on it."

"The pulse transformer should be checked for temperature every four hours, and instrument calibration should be performed as usual."

"If any abnormality occurs, record the data first, and do not touch the wiring."

"rest assured."

Old Sun patted the dust off his hands.

"I'll guard Workshop Number One."

Jiang Ming wrote four characters on the blank space of the last page of his notebook.

Fengtai tomorrow.

The pen hovered over the paper for a moment, then moved down one line and wrote a Russian abbreviation and its corresponding Chinese translation.

МАГ.

Magnetron.

He closed the notebook and placed it on top of the kraft paper notebook at the bottom of the toolbox.