Atomic Force Electron Microscope (AFEM), which is famous for its high precision, has a magnification of hundreds of thousands of times, but its cost is over 100,000 yuan, which makes it difficult to enter the classroom of ordinary middle schools. But at the end of the summer school of Tsinghua University recently, students from universities at home and abroad have used building blocks to build atomic force microscopes with nanometer accuracy, which cost less than 1,000 yuan. It is understood that these low-cost microscopes are expected to be applied to secondary school classroom in the future.
With 3D printer
5 days to build a microscope.
This summer vacation, at Tsinghua University International Summer School, more than 30 college students from Oxford University, London University, Tsinghua University, Peking University and other universities at home and abroad were divided into groups of 5 to 7 people, fighting continuously for five days, using building blocks to build a usable atomic force microscope. In addition to Lego building blocks, the students also used a 3D printer from the Basic Industrial Training Center to print out some components.
Compared with some university's "summer school" courses, which mainly focus on traveling and relaxation, this summer school challenge project can be described as "high-intensity ascetic march". Few entertainment activities are arranged. Students need to mobilize their abilities in an all-round way, spend a long time in the laboratory, and complete a microscope in a very limited time. It is a formidable challenge for everyone.
Before the arrival of the judges, Zhang Yunyan, member of the third group, was still trying to debug the atomic force microscope made by his group. He did not hide his pride: "The structure of the device we designed is very ingenious. Most of the building blocks can be fixed with a small amount of metal components." The second-year Ph.D. student at London University did a good job in scientific research this year. His mentor "approved" him for a month's vacation. He signed up for the activity. Atomic force microscope is a very high-tech thing. I often use it in research. When I saw this activity, I thought, is it not very challenging for such high-tech things to be made out of building blocks? So I ran back from England to play with blocks.
Why do we choose to make atomic energy microscope as the goal of activity? Professor Franois, the organizer of the summer school and deputy director of the Center for Micromechanics and Nanomechanics of Tsinghua University, said: "Atomic force microscopy is a very important instrument in the field of surface science research. On the one hand, the microscope is very expensive, but at the same time, its mechanical structure is simple, so it is possible for novices to make it in less than a week.
Like a blind man who sees the world.
Recently, reporters saw these microscopes at Tsinghua University. On the first day, I thought it was a toy robot built with a small block of wood, about 30 centimeters high. The only place where we can see "high technology" is that they are full of all kinds of lines. "Such guys, can we see things we can't see?"
The students told reporters not to underestimate this slightly rough "robot", building blocks with high-precision photodiodes, piezoelectric ceramic tubes and other components. Lasers emitted by fixed devices are reflected by cantilevers and irradiated on photodiodes. With the change of different positions, different reflection angles are obtained. These angle data can be restored by a computer chip to obtain the three-dimensional shape of the surface of the object being observed.
The students give an example of image: the blind understand the world mainly by touching and perceiving its surface shape, and then form the understanding of the contour of the object through the brain image thinking. The principle of atomic force microscope is also true. Gu Xueyong, an associate professor in the Department of Industrial Engineering of Tsinghua University, said that the atomic force electron microscopy (AFEM) made by students in five days had been able to "see" objects of nanometer size, far beyond the observation scale of ordinary optical telescopes.
The cost of building microscope is saved by 99%.
As the organizer of this course, Gu Xueyong told reporters that microscopy is a common teaching instrument in senior high schools, but the magnification of general optical microscopy is not high, sometimes it can not meet the needs of students. The atomic force microscope has a high cost and the average cost is more than 100 thousand yuan. The cost of building microscope will not exceed 1000 yuan, and the difference between them is 100 times. The purpose of this summer school course is to inspire students to design atomic force microscopes for middle school and middle school students as props for classroom teaching.
It is noteworthy that in the selection process, the organizers also specifically invited eight senior high school students from many secondary schools, including secondary schools attached to Tsinghua University, as judges. The students were very careful and commented on the works of big brother and big sister one by one. "Some of the works are not very operable. High school students often shake their desks when they use them. Earthquake-proof measures should be added." Ouyang, a senior high school student in the middle school attached to Tsinghua University, said Chu. Some middle school students think that although these "building block electron microscopes" are very cheap, the maintenance conditions are very poor, long-term use of maintenance, accuracy calibration are all problems, "We can't throw them away once, right? The cost is still high. "
Almost all middle school students told reporters that they had not been exposed to atomic force electron microscopy before. The school's optical microscopy can only magnify tens of times to look at cell walls and cell fluids. "The college brothers here say that the microscopes they made can even see the surface structure of folding proteins and nucleic acids in the cytoplasm." This is like finding a new world for us. "