Jie LU,Yongli GAO,Xiaojing WANG,Chenyuan BAI,Bing WANG,Ziniu WU

School of Aerospace Engineering,Tsinghua University,Beijing 100084,China

KEYWORDS Academic output;Aerospace;Education;Favorite activity;Students

Abstract The development of aerospace science and technology largely relies on the education and academic contribution of students in universities covering aerospace science and technology.The School of Aerospace Engineering of Tsinghua University,with a history of eighty years since the set-up of its Department of Aeronautical Engineering in 1938,graduated 5273 undergraduate students,1939 master students and 931 Ph.D.students.This paper provides an overview and analysis of the data related to undergraduate,master and Ph.D.students of this school.These data include the historical evolution of number of students and the actual status of students like their various interests and academic performance.The data and information shared in this paper may be useful for comparative study and for those who need primitive data to study relevant issues such as mental health of students,promotion of gender balance and educational improvement.

1.Introduction

Tsinghua University established its aeronautical discipline in 1934,on which von Karmann offered advices in its early development,and this is the earliest discipline of aeronautics founded in China.Department of Aeronautical Engineering of Tsinghua University was set up in 1938,and was moved off to form Beijing Institute of Aeronautics(now Beihang University)in 1952.Department of Engineering Mechanics(DEM)was established in 1958 to retain some activities in aerospace research and education,which laid a foundation for the establishment of School of Aerospace Engineering(SAE)in 2004.This school includes the DEM and a new department called Department of Aeronautical and Astronautical Engineering(DAAE).

Exactly 80 years have passed since 1938.During these 80 years,5273 undergraduate students,1939 master students and 931 Ph.D.students graduated from this school/department.It may be of reference values for government agencies,industries,universities,professors and newly enrolled students to share the data,which reveal the evolution of number of students graduated,its correlation with the evolution of faculties and major historical events,the actual quality of education in terms of the productivity of Ph.D.students,and the interests of undergraduate students in various activities.

The education history alone is of interest for both education studies and government investment.For instance,in each year,the USA National Science Foundation provides 72 tables including detailed data on the demographic characteristics,educational history,sources of financial support,and postgraduation plans of doctorate recipients.1

As pointed out by Levecque et al.,2research policy observers are increasingly concerned about the potential impact of current academic working conditions on mental health,particularly of Ph.D.students.Mental health has been thought to be associated with the publication pressure of Ph.D.students for their dissertation work,since the publication is a prerequisite for an academic career3and this mental health problem in turn affects the overall quality and quantity of individuals’research output.4Thus,the data concerning the productivity of Ph.D.students may be useful for those who wish to make prediction of mental health problem from such data.For those who are concerned with the motivation and health behavior change of students,the duplication checking data of student thesis may be interesting.The low rate of duplication may be indicative of perfectionism that is estimated to increase over time in the United States,Canada,and the United Kingdom.5

The major data reported here come from the Record of Tsinghua University,6the report for the 80th anniversary of the SAE,7internal reports of the school8–18and the database of education of the University.19

This paper is organized as follows.Section 2 is concerned with undergraduate students.We will display the evolution of number of undergraduate students with correlation to the number of faculties.We will also show their interests in participating in various activities.

In Section 3,we display the evolution of number of master(including master of science and master of engineering)and Ph.D.students,with correlation to the number of faculties.We will also discuss their academic activities in publication and in attending conferences.The quality of the work of Ph.D.students will be displayed using the number of papers published by each student,duplication checking data of their Ph.D.thesis and blind peer review of their Ph.D.thesis.

In Section 4,a summary is presented.

2.Undergraduate students

The evolution of the number of undergraduate students is displayed in Fig.1(a)for the period of 1936–1979 and Fig.1(b)for the period of 1980–2017.

During the period of 1936–1939,only 33 students graduated from the aeronautical discipline.In 1960–1969,1237 students graduated from the DEM.The number of undergraduate students graduated then dropped to 641 in 1970–1979,and became 697 in 1980–1989,847 in 1990–1999,and 348 in 2000–2003.In 2004,the DEM was expanded to the SAE and since then 1272 undergraduate students have acquired their bachelor degree from the school.

The number of yearly enrolled undergraduate students largely oscillated before 1979,due to various historical reasons.During 1980–2003,the number of yearly enrolled undergraduate students was around 80.Since 2004,the founding year of the SAE,the number of yearly enrolled undergraduate students has exceeded 100 except in 2006 and 2007.The number of teachers decreased from 188 in 1982 to 71 in 2003,and then increased to about 110 in 2018.Moreover,the number of nonteacher faculties was in the order of 100 in the 1980s and dropped to the order of one tenth in recent years.In 2017,there were in total 516 undergraduate students in the school,compared to 110 teachers,meaning that the student-teacher ratio is 5.32.The lower number of non-teacher faculties means that many graduate students(notably Ph.D.students)are involved in undergraduate education,serving as institutors and assistant teachers.

As can be seen from Fig.1(a),the evolution of the number follows a quite irregular shape before the end of 1970s.This is largely due to historical events.

The data are incomplete.For instance,we are unable to find the number of students enrolled before 1938 and the number of students graduated between 1940 and 1959.During 1966–1971,there was no student enrolled,due to the Great Cultural Revolution.The large amplitude oscillation of the number of students enrolled before 1980 may be associated with the Sino-Japanese war,Second World War,Internal War and the establishment of People’s Republic of China in 1949.In 1952,the number of students enrolled reached 350.In 1952,the old SAE was moved off to form Beijing Institute of Aeronautics so that there is no student enrolled during 1953–1954.Between 1953 and 1957,teaching activities did not stop and the number of enrolled students gradually increased until 1958 when the Department of Engineering Mechanics and Mathematics(later on called Department of Engineering Mechanics)was set up.

Female students usually constitute a very small fraction of the total number.For instance,the undergraduate students enrolled in 2014 were divided into 6 classes,Class 1 had 5 girl students among 15 students in total,Class 2 had 2 among 31,Class 3 had 2 among 20,Class 4 had 0 among 13,Class 5 had 0 among 29,and Class 6 had 2 among 28.Thus,there was only 11 girl students among 136 students in total(note that the total number displayed in Fig.1(b)is 126 for 2014,because 10 students counted here are officially from other departments or schools).Fig.2 shows undergraduate students in outdoor activity(left)and in class(right),from which we can see much less girl students than boy students.Therefore,the gender balance in the education of aerospace engineering should be changed in the future,with the consideration of enhanced motivation of female engineers.

Apart from course studies,undergraduate students have diverse interests.Fig.3 shows the most favorite and most valued activities,according to a survey conducted in 2015 by the student association called LixiaoYi(a WeChat official account).20Of the students,31%mostly like the Student Day;24%mostly love social practices;20%are in favor of Schoolboy Day(November 12th)and Schoolgirl Day(March 7th).

Attention may be drawn to the fact that only 25%of students are fond of the rest activities such as sports,scientific innovative projects,diathesis enhancement,etc.

However,the activities that students consider to be most valued show different percentages.37%of students most care social services;23%consider that sports are the most important;17%attach importance to research;hobbies and interests occupy 17%.Since more than 50%of the students will do research after graduation,17%of the students mostly caring research appears to be too low,meaning that for most students,doing research is simply a choice not driven by interests.

Fig.1 Evolution of numbers of undergraduate students and faculties.

Fig.2 Undergraduate students in outdoor activity(left)and in class(right).

The research of undergraduate students is of high quality.For instance,in 2017,four undergraduate students published papers as first authors in international journals,including Soft Matter,21Applied Thermal Engineering,22Experiment in Fluids23and Physics of Fluids.24

The Student Day is organized independently by each school or department and is actually a final stage show,including the accomplishment performance of students,DV short film,and the introduction of the person of the year,and so on.It is self-organized by the students once a year,who would like to take after-class time to prepare the show-programs in two months.The Student Day,as a student celebration activity,is expected to help students to understand the campus culture and promote the student’s comprehensive development.The students love such activity because they consider it very beneficial.It especially offers great opportunity for interacting with other students.The student’s hobbies and interests are extracurricular activities.Commonly,the students will form a group with around 10 persons to perform an activity in the society,such as voluntary support education,investigation of nature or human heritage,and promotion of environmental protection.This is a typical education under national conditions of China,which will help the students understand the society and culture besides the knowledge in textbooks.

Fig.3 Most favorite and valued activities of undergraduate students.20

The Schoolboy Day(November 12th)and Schoolgirl Day(March 7th)are different from the Student Day.Schoolgirl Day is believed to originate from Shandong University.Since the girl students are far less than the boy students in the university,the boy students select just one day before International Women’s Day(March 8th)to hold a celebration and make some memorable gifts to all the girl students in their class.By contrast,the girl students would like to feedback to the boy students on the day after November 11th(Singles Day),blessing them to find their girlfriend earlier.As a result,November 12th is the Schoolboy Day of Tsinghua University.

3.Master and Ph.D.students

The evolution of the number of graduate students is displayed in Fig.4 for master students and Fig.5 for Ph.D.students.The number of master students graduated in the period of 1981–1989 was 276 and this number increased to 353 in 1990–1999 and 543 in 2000–2009.Only since 1984,we have had Ph.D.recipients.During 1984–1989,the number of Ph.D.recipients was 42.This number was 167 during 1990–1999 and 332 during 2000–2009.Since 2010,376 Ph.D.students have received Ph.D.degrees.

The number of yearly enrolled Ph.D.students gradually increased from 1982 to 2017.However,the number of faculties did not change significantly during this period.This means that faculties put much more time to supervise Ph.D.students and had less time to advise undergraduate students.

In 2017,there were in total 664 graduate students enrolled in the school,and 70%of them were Ph.D.students.Since the total number of teachers was 110,it means that in average each teacher supervised more than 6 graduate students.

Table 1 displays the number of Ph.D.students enrolled and graduated each year according to disciplines during 2008–2018(Me means Mechanics,AST means Aerospace Science and Technology,PEET means Power Engineering and Engineering Thermodynamics).Only since 2013,we have Ph.D.students graduated from the discipline of Aerospace Science and Technology,because it was allowed to enroll Ph.D.students only since 2009.More students are enrolled for Mechanics than those for the other two disciplines.

Fig.4 Evolution of numbers of master students.

Fig.5 Evolution of numbers of Ph.D.students.

Table 1 Number of Ph.D.students enrolled and graduated each year during 2008–2018.

Table 2 Median years to obtain doctorate for 2013–2018.

Table 2 gives the median years for Ph.D.students to obtain their Ph.D.degree since enrolled into the Ph.D.program.Ph.D.A means Ph.D.students enrolled in Ph.D.study soon after their undergraduate study.Ph.D.B means Ph.D.students enrolled in Ph.D.study after their master study.Ph.D.C means those who are transferred into Ph.D.program during their master study.It is shown that 55%of the Ph.D.A students got their Ph.D.in 5 years which is the official period.Only one student got her Ph.D.in 3.5 years.The longest record is 8.5 year.In average,Ph.D.A students need 5.44 years to get their Ph.D.,Ph.D.B students need 4.74 years,and Ph.D.C students need 3.22 years.USA National Science Foundation reported Survey of Earned Doctorates by National Center for Science and Engineering Statistics,1and this statistics shows that the averaged years to obtain doctorate since Bachelor are 7.3 for engineering Ph.D.recipients in 2016,which is much longer than 5.44 years for Ph.D.A in our school.

Ph.D.A requires 5.32 years to receive their Ph.D.in Mechanics,5.65 years in Aerospace Science and Technology,and 5.60 years in Power Engineering and Engineering Thermodynamics.

Since 1998,568 Ph.D.students have received their Ph.D.degree.The age distributions of Ph.D.recipients are shown in Fig.6.It is shown that for Ph.D.A(363 students in total),the distribution is close to lognormal distribution,the most probable age to receive Ph.D.is 28.The average age to receive Ph.D.degree is 27.8.For Ph.D.B(159 students),the distribution is a quite irregular one,because of the large difference of their ages at which they were enrolled into the Ph.D.program.The average age to receive Ph.D.degree is 33.16.For Ph.D.C(46 students),the distribution is regular and close to lognormal one under the age 33.One gets his Ph.D.degree at 34 and two at 36.The average age to receive Ph.D.degree is 28.78.When the three types of Ph.D.programs are considered together,the average age to receive Ph.D.is 29.39.

Fig.6 Age distribution of Ph.D.recipients.

According to Survey of Earned Doctorates by National Center for Science and Engineering Statistics,1for Ph.D.students in the field of engineering in USA in 2016,1.4%got Ph.D.at the age of 25,59.8%got Ph.D.at ages 26–30,27.6%got Ph.D.at ages 31–35,6.7%got Ph.D.at ages 36–40,2.2%got Ph.D.at ages 41–45,and 2.3%got Ph.D.at ages over 45.The average age of Ph.D.recipients in USA in 2016 is 30 in the field of Engineering,compared to 29.39 in our school.

As academic achievement,254 Ph.D.students published in total 950 papers as major authors( first author,or second author but with his/her supervisor as first author)in international journals(indexed by Web of Science)during 2013–2018.In average,each Ph.D.student published 3.74 papers in international journals,and 2.85 papers as major author.

The academic achievement in terms of paper published may be considered as very great.In fact,the administration requires each student to publish papers in international journals to avoid the blind evaluation of their Ph.D.thesis(2 papers indexed in Web of Science for Mechanics and 1 paper indexed in Web of Science and another one indexed in Engineering Index for Aerospace Science and Technology).More details are given in Table 3.It is interesting to note that,though the requirement for Ph.D.student enrolled in Power Engineering and Engineering Thermodynamics is looser(1 indexed by Web of Science or 2 indexed by Engineering Index),Ph.D.students from Power Engineering and Engineering Thermodynamics publish the most.The motivation of publication of students may also come from their career interest after their Ph.D.study.As shown in Fig.7,starting from 2014,most of the Ph.D.recipients continue their work on research,either in universities or in other institutions with research department.

Fig.7 Fraction of Ph.D.recipients choosing research as their postgraduate career.

Table 3 Number of papers(indexed in Web of Science)published by Ph.D.students during 2013–2018.

Table 4 Data of blind evaluation during 2010–2018.

Fig.8 Ratio of Ph.D.students participating in international conferences.

Blind evaluation of Ph.D.thesis is in fact applied to most of students independent of number of papers they published.Table 4 displays the data during 2010–2018.The experts invited for blind evaluation are required to rank A,B,C and D,which mean very good,good,average and passable respectively.It can be seen that 83.88%of replies are A,14.63%are B,and the number of students receiving C and D is very small.

Duplication checking is applied to each Ph.D.thesis.The duplication ratio is below 1%for 92.37%of Ph.D.theses,between 1%and 2%for 3.05%of Ph.D.theses,between 2%and 3%for 3.82%of Ph.D.theses,and over 3%for only 0.76%of Ph.D.theses.

The Ph.D.students are financially supported to participate in international conference.As shown in Fig.8,the number and percentage of Ph.D.students participating in international conference increase abruptly since 2016,and now almost 84%of Ph.D.students participate in at least one international conference during their entire enrolled period.In 2017,25.32%of graduate students(474 in total)attended an international conference.

4.Summary

Some useful data concerning the education of undergraduate,master and Ph.D.students in the SAE of Tsinghua University are displayed and analyzed in this paper.Though the data are not fully complete,the following conclusion may be drawn.

Before 1978,only undergraduate students were educated.The faculties focused on teaching and advising undergraduate students in that period.It means that undergraduate students in that period have high quality to do any type of work after graduation.Master students are educated only since 1978 and their number does not change significantly during 1978–2018(this number is around 50).Ph.D.program began since 1980,and the number of Ph.D.students enrolled in each year gradually increases from tens in the beginning to around one hundred in recent years.However,the number of faculties capable of advising graduate students does not change much in the recent years and maintains around 100 in the recent 20 years.This means that each supervisor has less time than before to interact with students.

In 2017,each teacher faced 6.64 graduate students and 5.32 undergraduate students.The number of non-teacher faculties is extremely small(15 in 2017),meaning that many graduate students are asked to serve as tutors or assistant teachers of undergraduate students.The gender balance is very poor in the school and its impact on the quality of education needs to be evaluated.

The undergraduate students show interests in various activities.Surprisingly,scientific research is not their most favorite activity.They are more interested in self-organized activities such as various types of Student Days.Since most of them will pursue research work through master or Ph.D.program,the influence of their non-guided interests in undergraduate period will need to be evaluated.

The academic output of Ph.D.students appears to be encouraging,since in average each student publishes almost 3 papers in international journals as major author.They are also very active in participating in international conferences and in further doing research work after receiving their Ph.D.degree.Ph.D.students starting their Ph.D.program since they received their Bachelor degree only need 5.44 years to accomplish their Ph.D.study and graduate at an average age of 27.8.

The data and information shared in this paper may be useful for those who wish to evaluate the quality and scale of education in their own discipline or universities,or to make additional researches such as the evaluation of mental health,investment and enrollment.Actually,the data available to us appear to be incomplete to do more advanced studies including correlation between various educational input and output.In the future,we will try to establish a database to include all the necessary information(investment,culture activities,academic input and output,interaction between students and supervisors,etc.)for improvement of education of both undergraduate and graduate students in the School of Aerospace Engineering.

Acknowledgements

This work was supported by Tsinghua University for Graduate Studies and for Evaluation of Degree Granting Authority.Doctoral student Yuzhe LIU and Congyi FU helped to improve some figures of this manuscript.