Tsinghua University's Basic Science Class for 20 years of development roughly

2018 is the 20th anniversary of the founding of the basic science class of Tsinghua University (referred to as the basic science class). Looking back on the process of exploration and development of the basic class, summing up the school's school -running philosophy, guidance guidelines, training models, and some specific practices, it is of great significance for the development of the Department of Physics and further improving the quality of teaching and talent training.

The development of the basic class has gone through three main stages.

1998 to 2004: The establishment, exploration and prototype of the basic science class

In order to improve the quality of the students and the Department of Mathematics at the time, and to deliver backup forces for the Higher Research Center (now Higher Research Institute) founded by our school in June 1997, Xiong Jiajiong, the executive deputy dean of the School of Management, and teaching in charge of the Department of Physics. Four professors, including the deputy director of the deputy department Shang Rencheng, the executive deputy director of the Department of Mathematics, the director of the Department of Mathematics, and the director of the Office of the Higher Research Center, submitted a report to the school in December 1997 to the school. Explore the new model of the cultivation of top talents, hoping to revive the glory of the School of Sciences of Tsinghua University.

Report to the school in December 1997

The school soon approved the report. President Wang Dazhong, Vice President Yu Shouwen in charge of teaching, Vice President Yang Jiaqing in charge of the "985 Project", and Chen Haoming, chief of the Academic Affairs Wu Mindheng, and Chen Haoming, executive deputy dean of the Graduate School. After discussion, the name "Basic Science Class" (referred to as the basic science class) and decided to start enrollment in 1998. Subsequently, under the guidance of the Academic Affairs Office, the "Leading Group for the Foundation Class" was established to appoint Shang Ren to become team leaders. Members include Baifeng Shan, Xiong Jiajiong, Xu Zhan, and Li Jiaqiang, director of the undergraduate admissions office, and then added Ruan Dong, director of the Department of Physics. The leadership group discussed and determined a series of issues of the foundation of the basic class, such as admissions, training plans, curriculum settings, special classrooms, and scholarships.

In response to the training goals, training models, and training plans of the basic science classes, the Department of Physics and Mathematics and Academic Affairs Office have been discussed, including two seminars. Eventually, the training goals and school guidelines for the foundation class were established.

Cultivate goals: cultivate top talents with innovative awareness and international competitiveness for basic disciplines such as physics and mathematics; cultivate new talents with good science literacy for other disciplines with high requirements for mathematics.

School guidance guidelines: wide diameter, thick foundation, strong practice.

On June 2, 1999, Mr. Yang Zhenning took a group photo with the first Grade 1998 student class.

In the cultivation plan of the Kenke Class, two aspects are particularly emphasized.

1. Play a physical and mathematical foundation. The course settings include 18 physics and mathematics courses, including 9 physics courses and 9 mathematics courses. The credits of mathematics courses exceed 1/2 of the total course requirements of the curriculum, and the mathematics and physics are in the same important position. It is possible for students to further develop in the direction of physics or mathematics, and they have certain advantages and characteristics; for those who think of other disciplines for further studies, a good mathematical foundation will also benefit them.

2. Carry out scientific research training for undergraduates. The "Special Research Course" (Seminar) for three semesters of compulsory courses (referred to as Seminar), the 5th, 6th, and 7th semester, 3 credits per semester. Students can choose the research direction according to their own aspirations, and choose the corresponding mentors inside and outside the school. Students can learn and study issues under the guidance of mentors, and also allow students to adjust their research directions and mentors. Several unknown questionnaire surveys showed that 95 % of students who expressed their recognition of "Seminar have help and help and greatly help themselves". Students generally believe that they can contact scientific research as soon as possible through Seminar, contact scientists, understand the process of studying research, and learn how to learn in research and gain a lot. Through Seminar, students can also find the direction they are interested in to determine the future research direction. Students are also satisfied with the flexible mechanism that Seminar can adjust the direction according to their own situation.

In terms of curriculum setting, the Department of Physics (Academy), the Department of Physics (Academy) of the Institute of Grand Class, also created a precedent. 4 semester. Two new summer courses are set up, "English Strengthening Training" and "Special Topics of Cross Discipline". These two courses are mainly to train students' ability to express Chinese and English. The teaching of "two lessons" in reform, hire excellent teachers to give class classes to reduce class classes, reduce classroom teaching, and increase discussions for 4-6 weeks.

Starting from the beginning, the Kenke class hired outstanding teachers inside and outside the school to teach. The teachers who have class in the basic class have the older generation of the physics department and the outstanding young and middle -aged teachers. In the questionnaire surveys before the student graduation, they are all students' favorite teachers. In addition, the Department of Physics has also hired the most distinctive outstanding teachers from brothers colleges to teach at the basic subject, such as Zhao Kaihua, Zeng Jinyan, Yu Yunqiang, Wu Chong, Zhong Xihua, Zhang Chengfu, Li Xianhui at Peking University; Chen Bin; Chen Weizheng, Qiu Weisheng, etc., Lu Dexin of Nanjing University, Zhang Yongde of the University of Science and Technology of China, Pei Shouzhen, Liang Canbin, Zhao Yan, Peng Fanglin of Beijing Normal University, Mei Fengxiang of Beijing University of Technology, Huang Weicheng of Xinjiang University, Wang Zhicheng of Lanzhou University, Huang Kesun of Massachusetts Institute of Technology, etc., received great welcome from students. In the autumn semester of 2004, Mr. Yang Zhenning went to "Ordinary Physics" (Ⅰ) for more than 140 people in the physics department, and arranged for the time to answer the time. Listening to the master's lectures, students can not only learn knowledge, learn how to think, but also establish a correct outlook on life and world view under the preaching of seniors and scholars. The Department of Physics also specializes in the teaching assistant of excellent young teachers as famous teachers, and strives to take over the courses of these famous teachers and carry forward. In the autumn semester of 2004, Mr. Yang Zhenning taught "Ordinary Physics" (Ⅰ) to the 2004 freshman of the Department of Physics.

The picture on the left is the class scene, and the lower left is answering questions after the class;

In November 2003, the Department of Physics submitted an application for adding a undergraduate major "Mathematics and Physics" (English name: Mathematics and Physics), which has been approved by Tsinghua University and the Ministry of Education. In the professional catalog of the Ministry of Education, mathematical basic science majors are given attributes to specialty majors.

In 1999, during the inspection and evaluation of the Science Base of the Ministry of Education, the expert group highly affirmed the training model of the basic science class. In 2004, the seven -year results of the basic science classes were obvious -the exploration and innovation of the top talent training model "(Shang Rencheng, Ruan Dong, Xiong Jiajiong, and Baifeng Shan) won the first prize of the Beijing -level higher education achievement award.

At this stage, the training goals, training concepts, training models, training plans, and curriculum settings of the basic science classes have basically established the foundation for subsequent development.

Beijing Education and Teaching Achievement (Higher Education) First Prize Certificate

2005 to 2010: Promotion of Basic Science Class -Mathematical and Basic Science Class

In 2002, the school began to consider building an undergraduate platform teaching model. In 2003, the four departments of the Academy of Mathematics, Physics, Chemistry, and Biology began to implement the "Science Platform Course". According to the requirements of the platform curriculum, all students (excluding foundation classes) of the science school (excluding basic science classes) have the same mathematics and physical basic courses. Among them, the basic courses of physical physics include ordinary physics and basic physical experiments in the two semesters.

On September 9, 2004, a "Basic Science Class Working Conference" was held in the Department of Physics to discuss several issues in the training process of the basic science class, involving training plans, enrollment, diversion, research, and top talent training. The meeting eventually reached an agreement on promoting the expansion of the basic class model.

On January 13, 2005, a seminar of the "Building of Big Digital Basic Platform" was held in the conference room 324 of the main building. After Bai Fengshan, deputy dean of the Academy of Science, made a report on "Research and Research on the Construction of Mathematical and Psychological Basic Platform", Zhu Bangfen, director of the Department of Physics, first spoke, proposing that the construction of a mathematics platform is based on the basic class. At the beginning, the brand of mathematics and physical majors was laid. Wang Jinsong, the vice president in charge of teaching, agrees with enrollment in 2005 according to large categories; strengthen mathematics and physical foundations. The courses in the previous two years are consistent, and don't be too professional. Chen Xi, secretary of the Tsinghua Party Committee, pointed out that Tsinghua University is very strong in engineering, but the academic atmosphere is not enough. Science should be strong in "training" -strengthen academics and advocate science! Mathematics and physics should cultivate talents in this direction, otherwise it will fail. Mathematics and physics can make talents faster. The pilot must be a bit stable. From the perspective of talent training, the cycle can be longer. Gu Binglin, the principal of Tsinghua University, concluded that the school actively promotes the "big category enrollment and training"; the establishment of a special working group should consider various issues in execution, and it is necessary to be fully and stable; The first two years of course should be consistent; political and ideological work must be in place, and the diversion must be flexible. For example, students can go to the information center when the junior is diverted, or they can go to the information pledge during the postgraduate. The meeting determined that Tsinghua will be enrolled in the basic science majors in mathematics in 2005.

Later, Wu Fengshan, deputy dean of the Academy of Sciences, Wu Nianle, Deputy Director of the Department of Physics, Director of the Business Office of the Department of Physics, Ruan Dong, Director of the Department of Basic Class, Li Jin, Deputy Director of the Department of Mathematics, and Wang Hui, deputy dean of the School of Information Director Huang Yidong formed a working group and began to discuss the implementation plan. After several rounds of discussions, the following consensus is formed.

(1) Since 2005, there are 3 classes of mathematics, 2 classes in physics, 2 classes of basic science classes, and 1 class of electronics. A total of 8 classes are enrolled in accordance with mathematical basic science majors. After enrollment, students and curriculum management are responsible for the Academy of Sciences. In this class, the counselor is configured to form a combination of class teachers and counselors from different departments. (2) In the first two years, students learned common basic courses to strengthen mathematical foundation and scientific literacy education.

(3) In the fourth semester, students determine the professional direction based on the principle of "scale control, two -way selection". Professional directions include: base science (mathematics), base science (physics), base science (application), and the school -based information college.

The Department of Physics arranges ordinary physics and ordinary physics experiment courses, which is consistent with the course settings before the basic class. It turns out that the textbooks used by the high -level calculus of the Kenke Class are Xiaoshu's "Calculus", while the Department of Mathematics replaced it with the "Mathematical Analysis" of Russian mathematician Zoric; Algebra". The depth of these two mathematical basic courses has greatly exceeded the original foundation's requirements for mathematical foundation.

In August 2005, 220 students in the first mathematics basic class of Mathematical and Psychological Basis enrolled. In the process of running a school, I found some problems. The undergraduate group committee of the Department of Physics conducted two unknown questionnaires on the 5 -character class. The data provided by the research team showed:

(1) The burden of academic curriculum is too heavy, which limits other aspects of development (accounting for 36%);

(2) The competition is too fierce, affecting the mental state and emotional communication (23%);

(3) The curriculum is too deep and difficult, and it is not suitable for the situation and needs of most people (accounting for 22%).

In response to the problems of students, the Department of Physics and Mathematics held many discussions and made some adjustments, but whether all students must learn the "Mathematics Analysis", whether the students have to conduct the concepts of scientific research and training in the undergraduate stage. Essence

August 17, 2005 The first Class of Mathematical Basic Science Class 2005 Welcome Ceremony

Considering the differences in mathematics and physical foundation in the large category, and the differences in the direction of the subject of mathematical and physics in the selected disciplines selected in the second year, in view of the differences in the teaching concept of the Department of Mathematics and the Department of Physics, the physics in 2007 physics in 2007, physics in 2007 Academician Zhu Bangfen, the director of the department and the dean of the Academy of Sciences, proposed to teach according to his aptitude, and build ordinary physics in the level, that is, open four series of ordinary physics for students to choose from: (1) ordinary physics; (2) basic physics (English); (English); (English); (English); (English); (English); (English); (English); 3) Principles and experiments of basic physics; (4) Ferman Physics. Among them, ordinary physics and basic physics (English) are traditional types. The former uses outstanding domestic textbooks, and the latter is taught in English. The newly opened basic physics principles and experiments and Ferman Physics are a founding in China. The former is to combine ordinary physics and ordinary physical experiments in a framework. The theoretical teaching and experimental teaching are organically integrated. The teachers who do experimental research are lectured and responsible for arranging supporting experiments. Ferman Physics uses the famous three -volume "Ferman Physics Lecture" as the textbook. As we all know, the lecture is the most difficult and highest level of ordinary physical textbooks recognized by the physics community. Ferman himself also believes that it is not suitable for college freshmen, and it is more suitable for people with some accumulation and experience of physical knowledge, such as graduate students and teachers. At first, some professors did not agree with Ferman Physics courses, but in order to solve some outstanding students who felt the problem of learning ordinary physics "eating unsatisfactory", especially students who participated in the National Physics Olympics, the Department of Physics made a bold attempt to try a bold attempt Essence After more than a year of preparation, the principles and experiments and Ferman Physics were officially opened in 2008. These two courses are taught in three semesters and small classes. In 2018, on the occasion of Ferman's birthday, we discussed and shared the Ferman class, which had been opened for ten years.

On January 7, 2009, Zhu Bangfen, Dean of the Academy of Sciences, Xiao Jie, Wu Nianle, and other deputy presidents, etc., reported to the vice president Yuan Yuan on some issues in the operation of mathematics and mathematics. The discussion has formed the following three conclusions.

(1) Freshmen will be compiled according to two intentions of mathematics and physics after enrollment. During the compilation class, we must meet the wishes of students as much as possible. The Kenhe 91-94 is managed by the Department of Mathematics, and the Kenhe 95-98 is managed by the Department of Physics.

(2) The Department of Mathematics is responsible for formulating two training programs in mathematical direction and (partial mathematics) application direction; the Department of Physics is responsible for formulating two training schemes in the physical direction and (physical) application direction. Two training schemes in the direction of the two departments and coordination applications. The general principle of training plans is to reduce the number of compulsory and restricted courses from the current situation and reduce the difficulty of curriculum. The first -year freshmen are limited to less than 25 credits per semester.

(3) Students can be converted between the four cultivation models according to their interests in the past two years according to their interests, and there is no threshold; the fourth semester is diverted.

In the subsequent execution, some concepts of the Department of Physics and Mathematics have never been reconciled in terms of teaching and training. On May 21, 2010, under the auspices of Vice President Yuan, the enrollment and training model of mathematics and basic science classes was held. The coordination meeting of the Department of Physics and the Department of Mathematics, finally agreed to start in 2011. The mathematical base class returned to the original foundation class, and was managed by the Department of Physics. This new enrollment training model is conducive to the physical and mobility of the Department of Physics and Mathematics, and establishes a curriculum system and scientific research practice training system that conforms to the laws of talent training. Undergraduates who have potential to develop potential. During this stage, the school began to consider the implementation of the "Tsinghua Academy Talent Training Plan" in 2008. The first batch of schools was selected for the school plan. Zhu Bangfen was the chief professor of the school physics class, and Li Shiqun was the project director. The school physics class aims to cultivate physicists with international first -class levels, and drive the school's basic scientific talents and other top -top innovative talents to further improve the quality. The academic spirit of the school physics class advocates the academic spirit of "the spirit of independence and the thought of freedom", inspires students to concentrate on physics learning and research, and grow into international first -class physicists. In September 2009, 17 students in the Department of Physics became the first batch of students in the Physical Education Class of Tsinghua Academy. In April 2010, the Tsinghua Academy Physical Class held a grand opening ceremony. Mr. Yang Zhenning, 13 academicians of the Chinese Academy of Sciences and leaders of the school attended. Subsequently, the "Tsinghua Academy Talent Training Plan" was included in the "Basic Disciplinary Student Training Plan" of the Ministry of Education and the Ministry of Education.

In April 2010, Tsinghua Academy's Physical Class opened Ceremony

Carrying out basic curriculum teaching and opening school physics classes are two major measures at this stage. It is of far -reaching significance for improving the quality of teaching and the training of tip talents in the physics department.

From 2011 to the present: Return to Basic Science Class

Starting in 2011, the Department of Physics has resumed 4 classes each year, including 2 physics and 2 foundation classes. Although the class number is divided into physics and foundation, the training mode still inherits the original foundation of the original science class: a good basis for mathematics, physical, and scientific research. The two -year courses of physics and Kenke are basically the same. By the fourth semester, students finally determine their majors, that is, choose physics specialty (basic physics) or mathematical basic science major (basic application) according to their own aspirations, and Complete the subsequent training plan. Students' dormitories are not adjusted.

In 2017, Tsinghua first enrolled students according to 16 large categories, and implemented a new model of "large category enrollment and general college", that is, large categories carried out one -year large category training. Training plans, especially basic courses in physics and mathematics; students in the second semester conduct professional confirmation and complete subsequent professional training programs. Mathematical categories involve 5 departments including the Department of Mathematics, Physics, the Department of Works and Foods, the Materials Institute, and the Aviation Academy. Cultivation of five colleges and departments. The physics majors and basic science classes of the Department of Physics belong to this category.

Adhering to the three -in -one educating concept of "value shaping, ability training, and knowledge teaching" of Tsinghua University, the teaching concept of Tsinghua University, through the teaching of the "integrated integration" and "thick number of the foundation, wide discipline platform", not only the basic subject world of mathematics, physics, etc. First -class academic research talents have laid a solid mathematical foundation, and also cultivate compound talents with excellent scientific literacy and innovative consciousness for other applied disciplines with mathematics and physics. While emphasizing the foundation of mathematics, it also focuses on the cultivation of comprehensive personality training and the influence of humanities and scientific spirit, thereby helping students to lay the foundation of future success. In fact, the major category of mathematics is to inherit the training concept of the foundation class.

August 24, 2017, the first category of mathematics category 2017 welcome new ceremony

【appendix】

1. The enrollment of the basic class

(1) From 1998 to 2004: The first student was special in the enrollment of the Kiko Class in 1998. The enrollment plan of the school had been reported to the Ministry of Education at that time, and the basic class did not catch up with the report plan. Later, negotiated with the Academic Affairs Office and the Undergraduate Admissions Office, mainly adopted the way of enrollment through two -way selection and best admission in enrollment (later called "second enrollment in the school", referred to as "two enrollment"). In fact, more than a dozen of the first students were "adjusted" from the college entrance examination enrollment, so that more than 40 people were admitted through two moves, including the National Science Experimental Class from Tsinghua University Class) Several students who were selected at the time were senior high school students. According to the policies of the Ministry of Education, these students from all over -rational classes could not participate in the college entrance examination and went directly to college after passing the interview assessment of the university.

In late August 1998, the first two moves began after entering the school. The first is to let the freshman know that there are two moves in the base class. At that time, the freshmen were in military training. They wanted to issue a notice through the school's freshman working group, but they thought they would cause inconvenience and did not agree. We had to do it ourselves and copied hundreds of "notice of selection and admission to basic science classes". The second is to organize preaching. In the big classroom of the three religions, the students who listened to the preaching exceeded our expectations. When answering questions, they were divided into two classrooms. The third is to organize interviews. The working group decides that each group of interview teachers are composed of teachers from the Department of Physics and Mathematics. The principle of selecting students is "a good basis for mathematics and physical and physical, and is interested in basic disciplines, hobbies or expertise." We not only look at the results of the college entrance examination, but also depends on the comprehensive quality of students, especially their hobbies for mathematics and physics. Through this two moves, we found that the two moves are a very effective way to select students, which is conducive to comprehensive inspections of students, and it has been retained and has continued until now. Two moves have been promoted by the school to the admissions of other special classes.

With the enrollment experience of the first -time student class, the enrollment pathway in the future is relatively fixed:

The first is selected from the four full -rational classes across the country. This channel lasted until 2004, because the Ministry of Education terminated the full -time class project in 2003;

The second is the second enrollment in the school;

The third is selected from all provinces in the country. Beginning in 2000, there are outstanding students with mathematics and physical specialties from the finals of the National Mathematics Competition and National Middle School Physics Competition.

In 2004, at this time, the base class had a certain impact in the society. After the approval of the leading group of the basic science class, the recruitment office first put more than 10 enrollment plans directly in the college entrance examination enrollment.

(2) From 2005 to 2010: From 2005, Tsinghua University began enrollment with basic science majors. At this stage, the enrollment of the eight classes in each session mainly adopts the approval of college entrance examinations. At the same time, the method of selecting secondary enrollment (the scale of 20 people) and mathematical physical competitions in the school will continue to be selected in the selection of students in the mathematical physical competition.

(3) From 2011 to 2017: Beginning in 2011, the mathematical basic science class returned to the training model of the original foundation, but the previous enrollment model was used, that is, the selection of college entrance examinations and subject competitions. auxiliary.

In 2017, Tsinghua opened a new model of large category training and Tongzhuang. There are only large categories on the college entrance examination catalog. After the new students enter the school, the five college departments are managed by the major category of mathematics. The second semester adopts the "application review" method. Through two -way selection, students enter the major of the corresponding hospital for follow -up learning. The Department of Physics still includes physics and basic science classes.

2. The class name of the basic class

In the history of the basic class, there have been different ways to compile.

In 1998, the first student of the basic class was enrolled, and the class was Kite 8, and it was a class. Because the Kenke class did not catch up with the enrollment plan incorporated into the school before, and did not know the number of enrolls, only one class was preset. But the first time was finally admitted to more than 60 people, which may be the largest class in Tsinghua history.

In 1999, the Kenke class had entered the right track. According to the school's practice, students were compiled into two classes after entering school. But after the start of school, we discovered that this class name was raised 9. At that time, we did not know why it was changed to this name. Teacher Shang Rencheng sent me to the Academic Affairs Office to learn about the situation. Teacher Chen Gang, then deputy director of the Academic Affairs Office, explained that the school recruited a liberal arts experimental class this year. Self -propedly advocated the foundation of the foundation class. Of course, this is inconsistent with the development of the training concept and the historical development. After that, the Academic Affairs Office agreed to be changed back to the basic class of the basic class from the next year. This method of compilation lasts until 2004.

Beginning in 2005, Tsinghua University conducted enrollment based on mathematical basic science majors. All eight classes were compiled according to the basic science class. The full name is the mathematical basic science class, referred to as mathematical base science classes. In the fourth semester, the School of Information Institute, which is mainly based on mathematics, physics, base science classes, and electronics, and students choose completely according to their aspirations. Students who are diverted to the Department of Physics are divided into two directions: the basic and basic applications of the basic subject, which corresponds to two classes of physics and two classes. This method of compilation continues until 2010.

From 2011 to 2016, the mathematical base class returned to the original foundation class, which was managed and cultivated by the Department of Physics. When students enter school, they are divided into two physics and two classes. In fact, these four classes are only the differences in the class name. The courses they have studied in the first two years are basically the same, both of which are mathematics, physical basic courses and public courses. In the fourth semester, students choose physics or mathematical basic science majors based on their own aspirations to complete the subsequent training plan. In fact, in 2010, the Department of Physics reported to the Academic Affairs Office. The initial idea was to compile the four classes of the Department of Physics according to the basic class, and it was later told that the Kenhe 13 had been occupied by the chemical biological base class. Because when the chemical biological base class was founded in 2003, its compilation class has been behind the base class. For example, its first class name is Big Science 33. In order to avoid disconnection of the class number, the Department of Physics decided to compile two physics classes and base science classes.

In 2017, enrollment and management began in 2017. When new students enrolled, they were randomly distributed to various departments of mathematical categories according to their wishes. These students did not belong to the departments, but they were managed. In order to be consistent with the classes when confirming the professional, the new students of the physics department are divided into two classes of physics and two classes in physics. After the professional confirmation, the students in the two classes of physics and the foundation of the base are officially determined. These four classes are only the differences in the class name. By the fourth semester, students choose physics or mathematical basic science majors based on their own aspirations to complete the subsequent training plan. ① Participating units and personnel include: Chen Yongcan, Wang Hui, Gu Pei, Zhang Zuo, Guo Dadong, Chen Haoming; recruited Zong Junfeng; Nie Hua Tong of the High Research Center; Wu Nianle, Shang Rencheng, Xiong Jiajiong, Xu Zhan, Ruan Dong, the Department of Mathematics Wen Zhiying, Li Jin, Yang Lijun, Zheng Jianhua, Gong Guanglu.

② Participants and personnel include: school leaders Gu Binglin, Chen Xi, Zhuang Lijun, Yang Zhenbin, Wang Jinsong, Education Office Chen Yongcan, Zong Junfeng, Zhang Zuo, Guo Dadong, Duan Yuanyuan, Zhang Wenxue, etc. , Baifeng Shan, Tengliman, the School of Information, Feng Zhenghe, Chen Xu, Wang Xiqin, the Department of Electronics, and the Department of Automation Guan Xiaohong, Zhang Yi, and Wang Xiong.

About the author: Ruan Dong, professor of physics at Tsinghua University, [email protected].

Citation format: Ruan Dong. Tsinghua University Basic Science Class 20 years of development roughly [J]. Physics and engineering, 2020, 30 (1): 3-9.

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