Preface to the special issue on seismotectonics of Asia: Progress in seismotectonic studies at Peking University

Seismotectonics is one of the new research areas of seismology with its main focus on studying the detailed seismic structure of lithosphere and upper mantle using seismic records, particularly the records collected at portable seismic arrays. Development of new seismic methods utilizing seismic arrays such as receiver functions, SKS-splitting analysis, body- and surface-wave tomography, and recently ambient noise tomography （Langston, 1977; Dueker and Sheehan, 1997;

Practical 2.45-GHz microwave-driven Cs-free Hˉ ion source developed at Peking University

A practical 2.45-GHz microwave-driven Cs-free H^- source was improved based on the experimental H^- source at Peking University（PKU）. Several structural improvements were implemented to meet the practical requirements of Xi＇an Proton Application Facility（XiPaf）. Firstly, the plasma chamber size was optimized to enhance the plasma intensity and stability. Secondly, the filter magnetic field and electron deflecting magnetic field were enhanced to reduce co-extracted electrons. Thirdly, a new two-electrode extraction system with farther electrode gap and enhanced water cooling ability to diminish spark and sputter during beam extraction was applied. At last, the direct H^- current measuring method was adopted by the arrangement of a new pair of bending magnets before Faraday cup（FC） to remove residual electrons. With these improvements, electron cyclotron resonance（ECR） magnetic field optimization experiments and operation parameter variation experiments were carried out on the H^- ion source and a maximum 8.5-mA pure H^- beam was extracted at 50 kV with the time structure of 100 Hz/0.3 ms. The root-mean-square（RMS） emittance of the beam is 0.25 Π·mm·mrad. This improved H^- source and extraction system were maintenance-free for more than 200 hours in operation.

A miniaturized 2.45 GHz ECR ion source at Peking University

A miniaturized 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source, which has the ability of producing a tens-m A H＋beam, has been built and tested at Peking University（PKU）. Its plasma chamber dimension is Φ30 mm×40 mm and the whole size of the ion source is Φ180 mm×130 mm. This source has a unique structure with the whole source body embedded into the extraction system. It can be operated in both continuous wave（CW） mode and pulse mode. In the CW mode, more than 20 m A hydrogen ion beam at 40 k V can be obtained with the microwave power of 180 W and about 1 m A hydrogen ion beam is produced with a microwave power of 10 W. In the pulse mode, more than50 m A hydrogen ion beam with a duty factor of 10% can be extracted when the peak microwave power is 1800 W.

THE PEKING UNIVERSITY MULTI—APPLICATION ION BEAM ANALYSIS SYSTEM

A multi-application ion beam analysis system and some research projects performed at this system are described. The lifetime of the RF ion source for He^- is discussed.

Professors and Graduates from Peking University School of Pharmaceutical Sciences Attending the 67th FIP Congress and CPA Centennial Anniversary

During the first week of September, 2007, the 67th world congress of pharmacy and pharmaceutical sciences,jointly hosted by the International Pharmaceutical Federation (FIP) and the Chinese Pharmaceutical

Stable Operation of the 2 K Cryogenic System for the Superconducting Accelerator at Peking University

A superconducting energy recovery linac test facility(PKU-SETF)was built at Peking University,and a 2 K cryogenic system,which is the first closed-loop 2 K cryogenic system for a superconducting accelerator in China,was constructed for the 1.3 GHz 3+1/2 cell dc-SRF injector.The main accelerator consists of two nine-cell TESLA-type superconducting cavities of the PKU-SETF.The commissioning and stable operation of this 2 K cryogenic system was carried out.A helium pressure stability of better than±0.1 mbar and a total refrigeration capacity of 65 W at a temperature of 2 K was reached.

Power Test of the Ladder IH-RFQ Accelerator at Peking University

A 104-MHz ladder interdigital-H radio frequency quadrupole accelerator(T-IH-RFQ)is developed for applying RFQs to heavy ion implantation and accelerator-based mass spectroscopy in recent years at the Institute of Heavy Ion Physics,Peking University.It could accelerate ions with a mass-to-charge ratio of less than 14,from 2.9 keV/u to 35.7 keV/u within a length of 1.1 m.The T-IH-RFQ cavity operating at H21(0)mode was constructed successfully.Based on a well designed rf power feeding system,the cavity was cold measured and tested with high rf power.In the case of cold measurement,the rf properties were obtained using a vector network analyzer with the help of a perturbation capacitor.During a high power test,the inter−electrode voltage was derived from the energy spectrum of x-rays measured by a high purity Ge detector.The results show that the specific shunt impedance of the T-IH-RFQ cavity reaches 178 kΩm,which could meet the requirements of beam dynamics design.

Low-Carbon Campus Construction Based on Ecological Footprint Theory:A Case Study of Shenzhen Graduate School,Peking University

Since the sustainable development has been widely acknowledged worldwide,the sustainable campus development based on low-carbon campus construction has already become a tendency of building resource-saving and environment-friendly society.It is a hot and difficult topic in the current campus planning to measure,estimate and construct low-carbon campuses.This paper calculated the ecological footprint of traffic,water,energy and daily life on the campus of Peking University Shenzhen Graduate School,obtained the energy consumption of each item on campus and individual low-carbon activities using questionnaire survey and interview,compared the data with those of other domestic and foreign campuses.The results showed that(1) Ecological footprint of Peking University Shenzhen Graduate School in 2016 was 4,269 hm^2,and per capita ecological footprint was 1.49 hm^2;(2) Total carbon emission in 2016 was 13.4×107 kg,among which power generation and food produced the most carbon emission;(3) Students had strong awareness of low-carbon life,and the main obstacles for low-carbon life were "Hard to change living habits","Greedy vanity",and "No efficiency instruction";(4) In terms of the overall proportion,control of energy consumption is the main approach of reducing campus carbon emission,which is similar to other domestic and foreign campuses.The carbon emission of daily life in Peking University Shenzhen Graduate School was significantly higher than that of foreign campuses,while that of traffic was lower.Suggestions and improvement measures were put forward in view of the existing problems.

Strategic Scientific and Technological Capacity-Building in Clinical Medicine in China:Taking the Innovative Development of Reproductive Medicine at Peking University Third Hospital as an Example

Based on the macroanalysis of the unbalanced development of the"demand side"and the"supply side"of clinical medicine in China,this paper elucidates the stakeholders,resources,and ecosystem of the strategic scientific and technological capacity-building and calls for a larger coverage,smoother supply chain,and more sustainable ecosystem to ensure the development of clinical medicine.Furthermore,focusing on the establishment and development of clinical reproductive health in China,the authors introduce the strategic scientific and technological capacity-building of reproductive medicine in Peking University Third Hospital,with an attempt to inform similar efforts in other fields and even the whole clinical medicine in China.

Neutron imaging at Peking University

Neutron imaging techniques were investigated at Peking University based on a 4.5 MV Van de Graaff accelerator.The thermal neutron radiography,fast neutron radiography and fast neutron resonance radiography were tested.The low neutron flux limits the image quality.A new radio frequency quadrupole (RFQ) accelerator based on neutron source with a yield of 1 012 n/s is being set up.

Research on the Campus Space Cognition and Active Path of Peking University Students

Questionnaire survey and investigation were carried out to get students’feelings and cognition about campus of Peking University Shenzhen Graduate School,and active paths of their daily routine were analyzed to fi gure out the relationship between cognition and path.Characteristics of the students’space cognition and time-space active path were analyzed,and the causes of these characteristics explored to summarize the laws of students’daily life,and provide references to know psychologic status of students.

Understanding hydrogen plasma processes based on the diagnostic results of 2.45 GHz ECRIS at Peking University

Optical emission spectroscopy（OES）, as a simple in situ method without disturbing the plasma, has been performed for the plasma diagnosis of a 2.45 GHz permanent magnet electron cyclotron resonance（PMECR） ion source at Peking University（PKU）. A spectrum measurement platform has been set up with the quartz-chamber electron cyclotron resonance（ECR） ion source [Patent Number： ZL 201110026605.4] and experiments were carried out recently. The electron temperature and electron density inside the ECR plasma chamber have been measured with the method of line intensity ratio of noble gas. Hydrogen plasma processes inside the discharge chamber are discussed based on the diagnostic results. What is more, the superiority of the method of line intensity ratio of noble gas is indicated with a comparison to line intensity ratio of hydrogen. Details will be presented in this paper.

Prevalence of Nutritional Risk, Undernutrition, Overweight/Obesity and Application of Nutritional Support Among Geriatric Patients at Peking University People’s Hospital

Objective To investigate the prevalence of nutritional risk, undernutrition, overweight/obesity, and the application of nutritional support among geriatrics so as to provide evidence for whether elderly inpatients with undernutrition and nutritional risk should receive timely nutritional support. Methods A total of 445 elderly inpatients in the Department of Geriatrics of Peking University People’s Hospital were consecutively enrolled from July 2010 to June 2011. The Nutritional Risk Screening 2002 (NRS 2002) questionnaire was used on the second day after admission. The application of nutritional support was investigated on the 14th day or the discharge day. The relationship between the nutritional risk and nutritional support was analyzed. A NRS 2002 score ≥ 3 was defined as nutritional risk. A body mass index (BMI)< 18.5 kg/m2 was defined as malnutrition, 24.0 kg/m2 ≤ BMI < 28.0 kg/m2 as overweight, and a BMI ≥ 28.0 kg/m2 as obese. Results A total of 445 patients were enrolled and 423 patients (95.1%) completed the NRS 2002. The prevalence of undernutrition and nutritional risk was 4.7% and 13.2%, respectively. Among 230 patients who were overweight/obese, the prevalence of nutritional risk was 6.1%. In total, 15 of the 56 patients (26.8%) with NRS 2002 scores ≥ 3 received nutritional support, and 14 patients (3.8%) with NRS 2002 scores < 3 also received nutritional support. The average PN: EN ratio was 1.6:1. Conclusion A certain proportion of elderly inpatients in the department of geriatrics were experiencing undernutrition or were at nutritional risk. The prevalence of nutritional risk did not increase significantly with age. The current application of nutritional therapy is inappropriate. Evidence-based guidelines are required to improve this situation. The NRS 2002 may not applicable for overweight/obese elderly inpatients.

Chinese college students' Web querying behaviors:A case study of Peking University

This study examined users' querying behaviors based on a sample of 30 Chinese college students from Peking University. The authors designed 5 search tasks and each participant conducted two randomly selected search tasks during the experiment. The results show that when searching for pre-designed search tasks, users often have relatively clear goals and strategies before searching. When formulating their queries, users often select words from tasks, use concrete concepts directly, or extract 'central words' or keywords. When reformulating queries, seven query reformulation types were identified from users' behaviors, i.e. broadening, narrowing, issuing new query, paralleling, changing search tools, reformulating syntax terms, and clicking on suggested queries. The results reveal that the search results and/or the contexts can also influence users' querying behaviors.

Special Issue:Celebrating the 70th Anniversary of the Establishment of Polymer Program at Peking University

The polymer program at Peking University(PKU)was founded by Prof.Xinde Feng in 1953,and is the earliest polymer educational and research organization in China.Nine undergraduates specialized in polymer chemistry,the earliest in China,graduated in 1955.Postgraduate education in polymer chemistry at PKU was initiated by Prof.Feng,from 1953 to 1965,he supervised 13 postgraduate students.In 1978 when China resumed Regulations on Academic Degrees,Prof.Feng recruited 8 threeyear master's degree students.Since then,PKU polymer program,under the leadership of Prof.Feng,has entered into a rapid development stage of postgraduate training.The first doctor of science degree in polymer chemistry was awarded in 1984,and two post-doctoral fellows joined PKU polymer program in 1989.

New progress of the miniaturized microwave ion source at Peking University

The generation of plasma in a microwave ion source involves confining electrons using a static magnetic field and energizing them with an electromagnetic field that transmitted into the plasma chamber.However,according to electromagnetics theory,there is always a cut-off size in circular wave guides for a given frequency.For a 2.45 GHz microwave,this dimension is 72 mm,which should theoretically prevent transmission of the microwave into the discharge chamber and no plasma can be generated.Since 2006 Peking University(PKU)has successfully developed a series of permanent magnet 2.45 GHz microwave ion sources(PKU PMECRs)with a discharge chamber less than 50 mm,capable of delivering tens of mA beams for accelerators.To explain this anomalous phenomenon,a hybrid discharge heating(HDH)mode that combines surface wave plasma and electron cyclotron heating has been proposed.This HDH mode not only successfully explains PKU PMECRs,but also predicts that the optimized inner diameter of the plasma chamber is 24 mm,which is confirmed by experiments involving different liners in the miniaturized microwave ion source.

SPECIAL ISSUE： RELIGION AND SOCIETY： CROSS-CULTURAL COMMUNICATION：Peking University＇s role in China＇s Anti-Christian Movement in 1922-1927

The paper gives an overview of the Anti-Christian Movement of 1922-1927, focusing on the role of Peking University faculty and students in the first stage of the movement. Statements by some important Peking University intellectuals, such as University President Cai Yuanpei （蔡元培） and Professors Chen Duxiu （陈独秀）, Hu Shi （胡适）, Zhou Zuoren （周作人）, etc. are discussed in detail. Special attention is given to those comments that stand out as against ＂majority opinion＂. Neither the Communists nor the Nationalists were key leaders during the first stage of the movement. It was the clash of core Chinese cultural values with those of Christianity and the Chinese desire to industrialize a country overwhelmed by the Western powers that were instrumental in the instigation of the Anti-Christian Movement.

Investigations and feedback on the training mode of professional master's degree of clinical pharmacy in Peking University and the preliminary exploration of Pharm. D. Education

In order to carry out the comprehensive reform of the professional master’s degree training mode of clinical pharmacy, we carried out interviews among 91 persons on the professional master’s degree of clinical pharmacy in Peking University School of Pharmaceutical Sciences and collected extensive feedback. We preliminaries explore the mode of Doctor of Pharmacy（Pharm. D.） Education, laying the foundation for Doctor’s education of professional clinical pharmacy in China. We conducted investigations and interviews among 91 clinical pharmacists and students of Peking University School of Pharmaceutical Sciences on the training of professional master’s degree and Pharm. D. education mode, which includes 67 postgraduates and 24 clinical pharmacists. Respondents put forward the problems of training mode and corresponding suggestions and opinions from different aspects during the investigation and interview. The results mainly divide into four aspects： curriculum setting, clinical practice, assessme nt system and teaching resources. Respondents put forward effective feedback on the above four aspects, which are beneficial to the comprehensive reform of the training mode of professional master degree in clinical pharmacy and preliminary exploration of Pharm. D. Education in China.

Peking University Health Science Center Model of Clinica Pharmacy Education and Clinical Pharmacist Services

In the 1950s, clinical pharmacy emerged in the United States and gradually developed into an indispensable component of the clinical services system, The American College of Clinical Pharmacy defines clinical pharmacy as a pharmaceutical field that focuses on the science and practice of rational drug use.

Recent progress of laser driven particle acceleration at Peking University

Recently, radiation pressure acceleration （RPA） has been proposed and extensively studied, which shows that circularly polarized （CP） laser pulses can accelerate mono-energetic ion bunches in a phase-stable-acceleration （PSA） way from ultrathin foils. It is found that self-orgizing proton beam can be stably accelerated to GeV in the interaction of a CP laser with a planar target at 1022 W/cm2. A project called Compact LAser Plasma proton Accelerator （CLAPA） is approved by MOST in China recently. A prototype of laser driven proton accelerator （1 to 15 MeV/1 Hz） based on the PSA mechanism and plasma lens is going to be built at Peking University in the next five years. It will be upgraded to 200 MeV later for applications such as cancer therapy, plasma imaging and fast ignitiou for inertial confine fusion.