Chapter 462: Did the stack work crash with the giant?

Mo Wenlin had two exams this week, and she was busy with her schoolwork, so she suspended her experimental work.
Xu Qiu was also busy writing "Science" articles, and had no time to experiment.
Therefore, the glove box in the laboratory is rarely empty.
Upon seeing this, Sun Wo saw the stitches, decisively occupied the glove box, and began to prepare the devices.
In the morning group meeting, although Wei Xingsi had no specific comments on the failure of their perovskite team's experiment, Sun Wo also felt a little pressure.
Therefore, he decided to rush to make a batch of devices today to prove himself!
It went well at the beginning. The tin-based two-dimensional perovskite film painted this time looks very uniform to the naked eye.
Sun Wo was very satisfied in his heart: "This wave has stabilized."
However, the good times did not last long, and tragedy happened during electrode evaporation...
Sun Wo found that no matter how he turned the potentiometer that controls the current, the ammeter always showed 0.
When evaporating electrodes before, occasionally the fuse was blown due to excessive current.
In that case, the ammeter will directly lose its indication due to the circuit break.
This is the first time that Sun Wo has encountered a constant current representation of 0.
Sun Wo had nothing to do, so he called Feifei Wu.
Wu Feifei walked to the main console of the evaporation instrument and checked for a while, but she couldn't figure out the reason.
So she called everyone in the office, including Xu Qiu and Duan Yun, to discuss countermeasures together.
After all, the evaporation equipment is used by everyone. If you can't fix it quickly, everyone's experiment progress will be affected.
Therefore, we must work together to solve the problem as soon as possible.
Lab instruments are indeed prone to various problems after being used for a period of time.
Some cases are caused by improper maintenance, such as the earlier failure of the circulating water system, because the deionized water has not been replaced for a long time, and the water in the water tank evaporates naturally, making the circulating water insufficient and unable to operate normally.
Some were damaged due to long periods of non-use. For example, a pump in Zhang Jiang’s laboratory was bought by Duan Yun at the time. It was useless after being put in a fume hood for more than half a year. When Xu Qiu used it, The motor of the water pump was found to be rusty.
This is similar to electronic products such as mobile phones and computers, which have been turned on for a year or two without any problems, but if they are not turned on for a year, they may not be turned on again...
The main reason is that these electronic devices are usually exposed to the air. Once they become damp, the electronic components are at risk of damage, and the electronic products in continuous use are not easy to get damp.
The energy loss of electronic components due to their own resistance becomes an effective barrier to protect them.
Of course, the use environment in the laboratory is usually harsh, full of organic solvent vapor, and the frequent use of circulating water, the air humidity in the fume hood is also higher than the outside world.
If the instrument is used in the fume hood too many times, too often, it is also prone to problems.
For example, heating agitators are the most prone to failure in organic laboratories. After a period of use, problems such as insufficient heating power, slow heating, inaccurate temperature sensor indications, and failure of the stirring function often occur.
For more than a year when Xu Qiu joined the research group, almost three or four heating stirrers were broken.
It wasn't that he broke it manually, but when he wanted to use it one day, he suddenly discovered that a certain function was out of order.
If the key is to be repaired, there are not many places to repair it, and it can only be repaired by the original factory.
After the warranty period of the original manufacturer, if you change a few accessories, the repair price will be about half the price of the instrument.
Moreover, the express delivery has passed, and then the express delivery will return, and it will take half a month or a month to go back and forth, which is very troublesome.
Therefore, the general approach is to buy a new one directly.
Of course, the main reason is that heating agitators are usually cheaper.
A few hundred yuan each, one change a year is also acceptable.
However, nowadays, for more expensive instruments such as evaporation equipment, if the instrument fails, you can only find a solution by yourself and see if you can solve it by yourself.
If you call the maintenance workers from the factory, you can't do it without thousands of dollars.
The maintenance cost of the instrument is based on the price of the instrument. For a six-figure instrument such as an evaporation instrument, the maintenance price will naturally rise.
Duan Yun walked over and took a look, and said in a more certain tone: "This is a high probability that the potentiometer is faulty, maybe there is a problem with the solder, or the potentiometer is damaged inside. In short, it should be removed and replaced with a new one. ."
He has a strong executive ability. After speaking, he started to find tools and prepared to work. At the same time, he suggested: "Sun Wo, I will transfer the soldering work to you. If there is a problem in the laboratory, you can come and maintain it, how about it?"
Sun Wo nodded: "Okay."
Seeing someone taking the job, Tian Qing, Mo Wenlin, and Han Jiaying returned to their desks one after another.
Xu Qiu stayed, and his judgment on Duan Yun was quite acceptable, so he didn't rush to leave, planning to learn soldering skills together.
He also copied Duan Yun's soldering skills and found that it was 10% of Tier 5.
Seeing this skill proficiency, Xu Qiu couldn't help feeling inwardly: "Duan Yun is indeed quite good in terms of hands-on ability. Before, he built a complete set of thermoelectric equipment from scratch. It is a pity that no one can inherit this set of equipment. Probably because there are no major achievements in the thermoelectric direction in the group, Wei Xingsi is not willing to go further."
Duan Yun took a new potentiometer from the work box, a screwdriver, a rod-shaped soldering iron with a screwdriver at the tip, and a box of rolled solder wire.
Xu Qiu still knows some general knowledge about soldering, and I have occasionally seen Duan Yun doing it before, but he has never actually touched it.
The principle of an electric soldering iron is that after power on, the resistance is heated, and the tip can reach a high temperature of several hundred degrees Celsius. When it exceeds the melting point of the solder wire by 50-100 degrees Celsius, the solder wire can be melted and processed.
The solder wire is generally divided into two categories, leaded and leadless.
Leaded is an alloy composed of tin with a melting point of 232 degrees Celsius and lead with a melting point of 327 degrees Celsius.
Among them, the solder composed of 63% tin and 37% lead is called eutectic solder, and the melting point of this solder is 183 degrees Celsius.
This kind of solder wire has many advantages, including:
Relatively low melting point, easy to process;
The melting point is consistent with the freezing point, which can make the solder joints solidify quickly and reduce the phenomenon of virtual soldering caused by loose components during the cooling process of the solder joints;
Good fluidity and low surface tension are beneficial to improve the quality of solder joints;
High strength and good conductivity.
But the shortcomings are also obvious, because lead is toxic, so this kind of solder wire is relatively rare in the laboratory.
Lead-free solder wires are usually used in laboratories. For example, solder wires made of tin-copper alloy are used in the group.
After all, the group is made of chemicals and is more sensitive to toxicity. Before buying various materials, they usually first check whether they are toxic, and then selectively purchase less toxic materials.
Unless, highly toxic materials have irreplaceable advantages and must be used.
For example, malononitrile used to introduce cyano groups, potassium fluoride used to introduce fluorine atoms, and organotin reagents used to introduce trimethyltin, had to be used in order to complete the reaction.
While preheating the soldering iron, Duan Yun took a disposable activated carbon mask and put it on, then turned off the control power supply of the evaporation instrument, and then used a screwdriver to remove the current heating module on the evaporation instrument console.
Xu Qiu found that the current heating module looks very large, with a length, width and height of about 502050 cm, but in fact it only fills up less than 10% of the space, with only a small potentiometer and one Digital display ammeter, and several wires.
Duan Yun took off the potentiometer and the lead, and showed Xu Qiu and Duan Yun: "Look, there is a burnt black mark on the back of the potentiometer. It should be that the resistance control function has failed. No matter how you switch it, connect it to The circuit has the highest resistance value, so the current value will continue to be displayed as 0."
Xu Qiu and Duan Yun thought that if it is completely damaged, causing an open circuit, the ammeter will not have a reading, and the apparent phenomenon will be similar to a blown fuse.
Duan Yun continued: "Sun Wo, you can tap the connection of the potentiometer with your mobile phone to prevent it from being disconnected after being removed."
Just as Sun Wo was about to do as he was told, Xu Qiu observed that there were labels 1, 2, and 3 next to the three "legs" of the potentiometer, and then interjected: "Let’s mark the wires and paste 1, 2, 3 Three tags, you can just check and connect directly later, and it will be convenient when you change it later."
Duan Yun nodded: "It's okay."
Sun Wo filled out the label, and after a while, the soldering iron was preheated.
Duan Yun took a pair of heat-resistant gloves and began to operate.
He first used an electric soldering iron to melt the solder between the original potentiometer and the wire of the current heating module, and then removed the broken potentiometer.
Then put the new potentiometer "three-legged up to the sky" on the ground, hold the solder wire in one hand and the electric soldering iron in the other, and drop the molten tin on the three feet.
Then start wiring, trying to make the wire on the current heating module solidify on the solder of the potentiometer.
This process is relatively cumbersome and requires some patience, because the solder has to be melted and solidified repeatedly, to check whether the wire is firmly soldered, and sometimes to repair the tin.
However, Duan Yun was a veteran at first glance. It only took him more than a minute to get all three solder joints.
Just as Duan Yun patted his and planned to install the current heating module back, Wei Xingsi suddenly walked into the laboratory with a document in his hand.
He saw Duan Yun squatting on the ground and asked: "What's wrong?"
Xu Qiu explained: "The potentiometer of the evaporation instrument is broken, and Duan Yun is repairing it."
Wei Xingsi said "Oh", then handed the documents in his hand to Xu Qiu, and continued: "They published an article "Nature Optics". You can read about organic photovoltaic laminated devices."
‘"Nature" big son magazine, layered? Hearing these two keywords, Xu Qiu raised his brows, took the article, and started browsing.
The highest efficiency, 14.0%.
Device structure, the bottom cell is DTDCPB: C-70, an all-small molecule system;
The top cell is PCE10: BT-CIC, and the non-fullerene acceptor BT-CIC used is a near-infrared acceptor.
BT-CIC, like COi8DFIC, entered Xu Qiu's pre-selected receptor library before, but its performance in the simulation laboratory is not as good as COi8DFIC.
Xu Qiu looked at several other pictures. They were all routine tests, including light absorption spectrum, EQE, J-V characteristic curve and so on.
"How is it?" Wei Xingsi asked: "It's not a threat to us, right?"
"Hmm..." Xu Qiu replied: "Threats are hard to talk about, but... if we want to send CNS now, 15% efficiency may not be enough, but it will be safer to be more than 16%."
"Yeah, but there is no way. We can't stop other research groups from letting them do research. Anyway, we are now 15.5%. Keep going, and hope to do it." Wei Xingsi paused and added: "Moreover, it's best to vote for this job before our winter vacation, otherwise it may take an extra month."
"I understand." Xu Qiu didn't bother to continue watching Duan Yun and the others repairing the evaporation equipment. He returned to the desk with the literature, intending to study it carefully.
In fact, Xu Qiu has been paying attention to the relevant trends of organic photovoltaic stacked devices.
But I haven't seen anyone working on a non-fullerene system before. This work should be the first article on a non-fullerene laminated device.
Judging from this result, they have a high probability of holding back their big moves. If they don’t make a move, it will be 14%. They have set the current world record for organic photovoltaics and put their own "Nature·Energy" article. 13.5% of the IDIC-4F system was killed.
However, the other party has done a good job of confidentiality, and there has been no news before, probably not a domestic research group?
Thinking of this, Xu Qiu glanced at the author of the article and found that it was not a domestic research group, but a Stephen R. Forrest research group from the University of Michigan and Ann Arbor in a beautiful country.
This person Xu Qiu still knows, he is a giant in the field of organic photovoltaics, a beautiful academician of the National Academy of Sciences, has more than 800 papers, the number of citations is close to 150,000, the H index is 170, and there are more than 300 patents...
It is interesting to say that the four authors of this "Nature · Optics" article, except Forrest who is the four authors plus the corresponding author, the other three are all domestic scholars.
Researchers in mainland China are very easy to recognize in the name of the paper, which is a simple Chinese pinyin, usually the first name is first, and the last name is last.
For example, there are many scholars with Chinese names in Bay Province and Kimchi Country, but when they write their English names, if they are three-character names, they will have one more separator "-" than mainland scholars, which makes it easier to communicate with mainland scholars. Scholars distinguish.
Someone said: "The top universities such as Qingbei University in China are the back gardens for providing talents to a beautiful country."
Mainly to explain the phenomenon that "the top domestic universities have many graduates flowing into other countries".
For example, for this article by Forrest, the three authors are all domestic researchers.
To a certain extent, this statement is indeed not wrong.
The proportion of undergraduate graduates from the Department of Materials Science and Engineering of Mordu University is about 30% each year.
Among them, the vast majority of students who go abroad for further studies choose beautiful countries, because the top ten universities in the world basically get together in beautiful countries.
And a few who can't apply to top international universities may choose to go to Great Britain to study a master's degree.
Xu Qiu didn't know the specific situation of Qingbei University very well, but most of it was similar to Magic University.
However, there are indeed more people going out, but the proportion of returning back is not low, because their parents, relatives and friends are all in the country.
Maybe only those who emigrate with their families will choose to stay abroad for a long time, but this is a minority after all.
On the other hand, the increase in the number of people going abroad is also related to the rigid requirements of the scientific research community for overseas exchange experience.
If you want to engage in scientific research, it is most cost-effective to go abroad after graduation.
Because some top international universities do not recognize domestic graduate degrees.
A master's degree from Qingbei University may still be useful. If it is an ordinary master's degree abroad, you may need to study for a master's degree again, which will waste a lot of time.
If you graduate with a Ph.D. and choose to go abroad to find a postdoc, you usually need to have a large number of high-quality articles at this time.
This is still quite difficult for students studying for a PhD in China.
Xu Qiu's casual AM is a special case.
The vast majority, 90%, even more than 95% of PhD students, let alone AM, it is very difficult to publish an AM sub-issue AEM and AFM.
However, it takes five years to find a big cow group to go abroad after graduating from a bachelor's degree.
Although flower growers have developed very fast in recent years, one thing I have to admit is that the beautiful country is still the world's leader in scientific research.
After all, the other party has accumulated hundreds of years. Although we have been running for decades, the other party has only moved a little slower, not completely stagnant.
This is a catch-up problem, a bit similar to the "three-generation effort" and "decade of cold window" between countries.
There is a more extreme example.
There are some "notorious" big cattle research groups in the scientific research circle of Beautiful Country. You only need to accept five or six years of "prison-like life" in it to get a CNS.
It is equivalent to saying that you have spent five or six years of your life in exchange for a CNS, but even so, many people are rushing to it, and it is not anyone who wants to enter can enter, and it must be good enough to be eligible for "prison". .
Because an article of CNS is available, you can get a "Qing Qian" when you return to your country and do it later. Use the experience gained during the "prison" period to "squeeze" domestic graduate students, and produce more results and make a "Jing Qing". "Identity is not difficult.
By this time, the scientific research road has basically been completed. For most scientific research workers, "excellent youth" is the end. Academicians are relatively difficult, because there may be hundreds of people lining up in front.
Next, you can choose to paddle for the elderly, or you can choose not to forget your original intention and continue to concentrate on scientific research and not to think too much about utilitarian things.
In other words, I have basically made it to the top, and I have obtained an account that is close to the full level in scientific research, and I can control the rest of my life relatively freely.
In addition to the scientific research circle, the education system of the beautiful country is also very interesting, which is very different from the domestic one.
Their strategy seems to be to add "points" to the university, while ignoring the middle school stage.
We often hear how good the universities in beautiful countries are, but we rarely hear how good their middle schools are.
On the contrary, there are a lot of powerful high schools in China, such as Maotanchang, Hengshui, the High School Attached to the National People's Congress, etc.... Every year, a lot of "exams" are stably output.
In Xu Qiu's view, from the perspective of the people at the bottom, the domestic approach is indeed for the people in general.
And this approach of the beautiful country is actually a means for capitalists to solidify the class.
Although the beautiful country can harvest the world, the total amount of resources is still limited, and it is impossible for everyone to become an elite.
Their structure is also a small group of elites and the vast majority of ordinary people. The existing elites will find ways to organize other ordinary people to transform into elites to grab their positions.
We seldom hear involution in beautiful countries, because it is essentially a process in which ordinary people compete with each other and become elites.
It is almost impossible for ordinary people in a beautiful country to transform into an elite, and naturally there is no such thing as involution.
The children of the poor at the bottom, they will go to cheap and poorly qualified public high schools, and then implement "happy education."
This has led to this group of people who have experienced education, but the actual level of education is not high. For example, some people still do not think that the earth is ellipsoidal, and still insist on "locality."
The children of the wealthy people at the top will go to private high schools with expensive tuition and very good teachers. Most of them also work hard like domestic children, and they can usually inherit the status of "elite" from their parents.
If you think about it, you can also know that if the beautiful country is really all "idiots" cultivated by "happy education", how could it still maintain the status of the world's leader and be overtaken by flower growers.
They also have a large number of elites supporting the entire country, but in this mode, they cannot give full play to the advantages of the entire population, and their hematopoietic capacity is insufficient. This may be an incentive for their decline.
Finally, the middle level is the worst.
Middle-class middle-class children, if they choose public middle schools with poor teachers and implement "happy education", there is a high probability that they will degenerate to the bottom, but because of better social welfare, there is a high probability that they can spend their lives happily.
There are also a few who try to hit the top level. Their first threshold is to enroll in private tuition. Because of the idea of ​​spending in advance and not saving money, basically don’t expect the family to pay, you can only rely on yourself, then it is student loans plus student loans. Part-time job.
The private middle school read out that the next level is the university tuition, which is also an astronomical figure. He continued to provide student loans and eventually graduated successfully and found a job that was twice as high as the minimum guarantee.
Then you will find that the cost of your own education needs to be repaid by betraying your ten, twenty, or even thirty years of life.
Take a closer look, isn't this just like the middle class of the parents?
After working hard for a long time, UU finally came out after reading www.uukanshu.com and found that he was still standing still.
Therefore, many people choose to lie flat.
Anyway, social welfare is good. Even if you eat and wait to die, the Federal Reserve will release water in emergencies, and the government will issue money for relief, so you can lie down.
Looking at the country, the high-priced school district housing, in fact, already has a bit of beautiful country flavor.
Therefore, the country has now begun to implement some policies in an attempt to curb the momentum in this area from expanding further.
This is because education is the most universal of several methods to break through the barriers of stratum. Once the road is blocked, the consequences can actually be seen.
This is also the advantage of being a late-comer country, which can avoid repeating the old paths that the predecessors took wrongly.
If one day in the future, there will be no "involution" in China, it may be a sad thing, because the high probability is not that "involution" will be eliminated, but...
High-speed text hand typing I have a list of chapters of the scientific research assistance system