Chapter 5: Cute sister

　　 Chen Wanqing put on disposable PE gloves, picked up a piece of substrate randomly with tweezers, and shone it at the fluorescent lamp on the ceiling.
　　 "Not bad, it was cleaned very cleanly," she exclaimed first, and then turned around:
　　 "However, this substrate was put upside down. It was my negligence. I just forgot to teach you to distinguish the front and back."
　　 "Fortunately, this petri dish is relatively clean, and the problem is not big, as long as you reconfirm each piece."
　　 She motioned Xu Qiu to walk to her to observe, and continued:
　　 "Take the substrate to a place where the light is good, look at the substrate from the side, and rotate it up and down slightly."
　　 "At this time, when you observe from the side with the ITO coating, you can see a continuous light blue or purple pattern, which is the front side; and from the back side, the pattern is discontinuous."
　　 "Okay, let me try." Xu Qiu also picked up a piece with tweezers and observed under the light.
　　Under the light, the ITO coating glows with a faint bluish purple.
　　According to the method given by the senior sister, he quickly distinguished the front and back of the substrate, put it face up, and put it back into the petri dish.
　　 Then he picked up another slice, looked at the light, put it back, and picked up the next slice...
　　 In less than a minute, all 11 films were put back.
　　 "Xu Qiu, you learned too fast," Chen Wanqing checked a few randomly, and exclaimed: "Scientific talent is good."
　　 "You can learn this at a glance, is it so difficult?" Xu Qiu was puzzled, but said calmly on the surface:
　　 "It's all taught by senior sisters."
　　 "Don't hold me up," Chen Wanqing sighed lightly: "When Teacher Wei taught me before, it took me almost half an hour to learn, and he always attacked me."
　　 Xu Qiu thought of the scene when Teacher Wei entered the laboratory, so he asked curiously:
　　 "In other words, Teacher Wei looks kind, but is he still fierce?"
"Ok……"
　　 Chen Wanqing replied perfunctorily, obviously not willing to talk more.
　　 Seeing this, Xu Qiu had to change the subject:
　　 "I continued to clean the substrates. I just installed a few more holders. This time I can wash a lot of films at once."
　　 "Okay, brother is working hard." Chen Wanqing put on a smile again.
　　…………
　　 Two hours later, Xu Qiu installed the last clean substrate.
　　 Then he took off his mask and gloves, put them in a special trash can, exercised on the spot for a while, took off his lab coat, and hung it on a hook on the wall.
　　 Even though the air-conditioning in the laboratory is adequate, Xu Qiu still sweats all over, and even the back of the lab coat can see obvious water stains.
　　 Scientific research is also physical work.
　　 Checking the system interface, the proficiency has risen again.
　　 Permission level: 1
　　 Points: 200
　　 Tasks in progress: 1
　　 Proficiency:
　　【Experimental operation class】
　　Cleaning the substrate (three-stage 30%/fourth-stage 50%)
　　【Instrument equipment tools】
　　 Ultrasonic Cleaner (Fourth order 50%/Fifth order 0%)
　　 Tweezers (third order 60%/fourth order 50%)
　　 Nitrogen Gun (Third-stage 30% / Fourth-stage 50%)
　　【The task has been completed, get 100 points. 】
　　【Get Novice Mission III. Increase the proficiency of any experimental operation to Tier 4 or above, and reward 300 points for completion of the task. 】
　　 The new mission is similar to the previous one, just continue to improve your proficiency.
　　 Unfortunately, there is no chance to complete the task today, because he even made an appointment with his roommates for dinner.
　　 Xu Qiu found that as his proficiency increased, his understanding of experimental operations improved.
　　 He is no longer stuck to the standard process, and can improve it according to the actual situation:
　　For substrates with more surface residues, extending the cleaning time in soapy water to 40 minutes can be easier to clean.
　　The cleaner substrate can cancel the soapy water cleaning process and start directly with deionized water.
　　 Moreover, through observation and analysis, I have roughly understood the purpose of each cleaning operation:
　　 soapy water is rough washing, which can wash away most of the electrode material or coating remaining on the substrate;
　　 deionized water can wash away inorganic impurities;
　　Acetone can wash away organic impurities;
　　 Isopropanol has a low boiling point and is easy to volatilize, which can make the substrate dry quickly under a nitrogen stream.
　　 In addition, Xu Qiu also arranged a reasonable time to dry the substrate while waiting for the ultrasonic cleaning process, which greatly improved the work efficiency.
　　 Of course, there are also disadvantages, that is, rotating shafts is very physical.
　　 In the end, Xu Qiu got a total of 60 clean substrates, which filled five petri dishes.
　　 He placed it in the form of a stack of Arhats, protecting both ends with his hands, just like holding a giant hamburger.
　　 When Chen Wanqing saw the 1, 2, 3, 4, 5 boxes of substrates that Xu Qiu had washed, she was surprised:
　　 "This...this is too much."
After 　　 said, she patted her forehead and said:
　　 "Oh, I forgot to remind you just now."
　　 "Normally, there is no need to blow-dry so much. Two boxes are enough. The rest of the cleaned substrates can be directly immersed in isopropyl alcohol, and then blow-dry when needed.
　　 Xu Qiu helplessly spread his hands, why this senior sister is a little cute, it seems not very reliable.
　　 "Excuse me, UU reading www.uukanshu.com" Chen Wanqing said with apologetics:
　　 "Leave the substrates for me to deal with at night. Thank you for your hard work today."
　　 "It's okay, it should be." Xu Qiu said.
　　 Chen Wanqing added: "By the way, if you come to the laboratory later, it is best to choose a fixed time so that it is convenient to arrange work.
　　The working hours of our group are from 9:30 to 11:30 in the morning, from 1:30 to 5:30 in the afternoon, and from 7:30 to 10:00 in the evening. Monday to Thursday all day, Friday morning and afternoon, Saturday off, Sunday afternoon and evening.
　　 There are no classes on Sundays, everyone is usually there, so it’s best to come over.
　　 Of course, you are an undergraduate, and Teacher Wei shouldn't care about you. "
　　 "Scientific research also has 996 blessings." Xu Qiu silently complained in his heart, then looked at the class schedule.
　　 A total of 14 credits of courses were selected this semester. One credit roughly corresponds to one class, and the number of courses is not too much.
　　 Seeing that there are fewer classes on Tuesday (today), Thursday, and Friday, Xu Qiu replied: "Then the afternoon of Tuesday, Thursday, and Friday, plus Sunday, how about it."
　　 "Okay," Chen Wanqing took a note and said:
　　 "If you have something to do, just tell me in advance, and you can come over at other times. Come on, add WeChat first."
　　 "drop."
　　 Xu Qiu looked at the senior sister’s WeChat. The nickname is her real name, and her profile picture is a travel photo.
　　 Finally, Chen Wanqing handed over three more bound paper documents and said:
　　 "These are three documents about organic solar cells, you can take a look first. If you have any questions, you can mark it down and ask me next time."
　　 Xu Qiu took the document and weighed it up, the weight was not light, so he stuffed it into his bag and said goodbye to the senior sister.