Beijing, 7^th February 2023 (BISTU)--- The year 2023 marked the beginning year of full implementation of the guidelines and philosophy of the 20^th CPC National Congress. The University has been rigorously learning and implementing the guidelines and philosophy of the 20^th CPC National Congress, National Working Conference on Science and Technology, and the 13^th Beijing Municipal Party Congress. Centering on the goal of achieving independence in high level science and technology and serving key and substantial demands of our nation and Beijing, we have also been optimizing environments for innovation, carefully organizing and conducting research activities, and playing a more active role in providing service with social and economic development of Beijing. During the Winter Holiday, researchers of BISTU have stayed on their duties and produced high level achievements.  

The team led by Prof. Zhu Lianqing completed exploration of epitaxy technology for short wavelength InAs/GaSb/AlSb/GaSb infrared superlattice detectors. Aiming at lowering dark current and operating bias, the team designed short wavelength pBin for carrier extractor. Photoluminescence spectra of absorption zone of 6InAs/6GaSb/5AlSb/1GaSb were shown in Figure 1, indicating that the cut-off wavelength (2.8μm) is in accordance with design. XRD test showed that half band width of satellite peaks in absorption zone is 33s. AFM scan showed that RMS is 0.17nm in the 50×50μm zone with relatively small degree of surface roughness. The results told that the Lab has achieved breakthroughs in epitaxy technology for short wavelength infrared superlattice detectors, which laid solid foundation for future device manufacturing.  

Figure 1: Full structure and PL absorption peaks of epitaxy materials for short wavelength infrared superlattice detectors 

Figure 2: Epitaxy materials for short wavelength infrared superlattice detectors 

Meanwhile, the Lab also explored techniques concerning unit devices of InAs/GaSb/AlSb/GaSb short wavelength infrared superlattice detectors and the relative proportions among orthophosphoric acid, citric acid, and perhydrol. Small degree of roughness was achieved and techniques of dark current suppression in surface passivation of Al2O3 were successfully tested with relatively better ohmic contact effect. The results showed that the Lab was basically capable in iteration of unit devices for short wavelength infrared detectors, which laid a solid foundation for design, epitaxy technology, device manufacturing, and device testing of short wavelength infrared superlattice detectors.  

Figure 3: Manufacturing and testing of InAs/GaSb/AlSb/GaSb superlattice unit devices  

“Automatic gear shift strategy for manual transmission of mine truck based on Bi-LSTM network”, a paper by Professor Wang Liyong, Director of Beijing Municipal Key Lab of Electromechanical System Measurement and Control, was published by Expert Systems With Applications（IF:8.665）. Based on analysis of actual data of TR50 mine cars, prediction model established, and an algorithm of deep learning, it produced a gear-changing plan of swiftness, convenience, intelligence, and high degree of prediction. Automatic transmission of special vehicles were improved in practice.  

Figure 4: Experimental truck and devices 

Figure 5: Box diagram for abnormal value evaluation 

Motion Planning of Mobile Robot Based on Goal-orientated Hierarchical Smoothing Optimization JPS Algorithm, a paper by Professor Wang Liyong, Director of Beijing Municipal Key Lab of Electromechanical System Measurement and Control, was published by Robot. GHSO-JPS (goal-oriented hierarchical smoothing optimization JPS) algorithm is proposed. Besides that, the multi-segment polynomial method and the collision penalty algorithm based on repulsive potential field are applied to trajectory optimization. The algorithm is of a better path planning performance, a higher efficiency and a better ability of trajectory optimization than the traditional motion planning methods.  

Figure 6  

A number of high level papers and innovative progresses have been achieved in two-dimensional materials by Qin Lei and Liao Qingwei, new-type sensor team members of Beijing Key Lab of Sensors (Beijing Research Center for Inertia and Acoustic Sensing Technology Engineering).  

The team proposed a solid-phase sintering and vapor-liquid-solid growth (SS-VLS-like) method of preparing a quantum-sized oxide material, i.e., black phosphorus (BP)@MgO quantum dot (QD) crystal with a strong piezoelectric response. When the BP@MgO QD crystal-based pressure sensor was applied with a dynamic finger pressure of 9-11 N, its output voltage proved that the pressure response of the sensor had a high signal-to-noise ratio. And therefore it would have great potential in the field of sensors. The paper was published by Journal of Advanced Ceramics (a top journal of Chinese Academy of Sciences with impact factor 11.534) with Liao Qingwei as the first author / corresponding author and Qin Lei as corresponding author.  

Figure 7: Schematic illustration of formation mechanism of BP@MgO QD crystals  

Figure 8: BP@MgO QD crystal-based pressure sensor 

In addition, the team has also made innovative progresses in two-dimensional wave-absorbing composites. Based on the Kirkendall diffusion effect, an in situ anisotropic-oriented growth strategy was advanced and a new magnetic carbon composite (γ-Fe2O3 @N-rGO/MWCNT) was prepared. The composite has a multihierarchical structure consisting of pinecone-like nanoflowers and a porous carbon framework. This kind of multihierarchical microstructure provides a rich wave absorption effect for the absorber. The developed in situ anisotropic-oriented growth strategy based on the Kirkendall diffusion effect shows great promise in the preparation of multiphase, multieffect, porous and multidimensional magnetic carbon composites through one-step pyrolysis by proposing a new concept for the design and preparation of MOF-derived nano electromagnetic wave-absorbing materials. The paper was published by Journal of Alloys and Compounds (November 2022, a top journal with impact factor 6.371) with Liao Qingwei and Qin Lei as corresponding authors.  

Figure 9: Schematic illustration of the conversion of PB nanoparticles into a multihierarchical structure γ-Fe2O3 @N-rGO/MWCNT composite by a pyrolysis technique.  

Figure 10: Schematic of the associated electromagnetic wave absorption mechanism of the γ-Fe2O3 @N-rGO/MWCNT composite  

Targeting at providing solutions to problems with developing flexible stretchable electrodes, the Team developed In-Situ growth of nanosilver on fabric technology. It can improve the binding force between Ag nanoplates and fabric fibers, increase the conductive path between Ag nanoplates, and improve the conductive properties and stability of conductive fabric. The paper was published by International Journal of Molecular Sciences (October 2022, a top journal, impact factor 6.208) with Liao Qingwei as the first author and corresponding author and Qin Lei as corresponding author.  

Figure 11: Tensile and electrical conductivity of conductive fabric by different processes.  

“Simultaneously Transmitting and Reflecting Reconfigurable Intelligent Surface Assisted NOMA Networks”, a paper by associate professor Yue Xinwei from School of Information and Communication Engineering, was published by IEEE Transactions on Wireless Communications（IEEE TWC, IF:8.346, top journal of Chinese Academy of Sciences）. It introduced simultaneously transmitting/refracting and reflecting reconfigurable intelligent surface (STAR-RIS) to achieve full coverage area. Outage probability and ergodic rate for users were derived. And effect of transmission/reflection mode upon theoretical system function was revealed, which provided theoretical foundation for optimized design of 6G communication network.  

Figure 12: System model of STAR-RIS assisted NOMA networks 

Figure 13: Outage probability versus the transmit SNR 

“Cloud-Edge Collaboration Dynamics Information Dissemination Model for Social Internet of Things”, a paper by Professor Zhang Yuexia of School of Information and Communication Engineering, was published by IEEE Transactions on Network Science and Engineering（TNSE, IF:4.553）. Based on communication dynamics, it analyzed information dissemination process on social internet of things and proposed a cloud-edge collaboration dynamics model for information dissemination for social internet of things, which would provide better explanation of information dissemination on social internet of things.  

Figure 14: Cloud-edge Collaborative Dynamics Information Dissemination Model.  

“Intelligent dispatching optimization of emergency supplies to multidisaster areas in major natural disasters”, a paper by associate professor Zhang Lin and Professor Qu Li from School of Economics and Management (working together with Shanghai Fire Research Institute of MEM), was published by Journal of Tsinghua University (Natural Science). The Study began with the rescue characteristics of major natural disasters and built an intelligent dispatching model of emergency supplies with consideration of uncertainties, lowest costs, and shortest time needed. Triangular fuzzy number was applied to represent uncertain variables and then turned the built-model into a multi-target intelligent emergency supplies dispatching model with certainty. Two-dimensional Euclidean distance weighting was used to simulate the calculation and solve the model. Then LINGO software was applied to calculate the phased emergency supplies transportation scheme. It would provide effective reference for decision-makers to develop disaster relief strategies.  

“Effect of medical researchers’ creative performance on scientific misconduct: A moral psychology perspective”, a paper by associate professor Zhang Na from School of Economics and Management, was published by BMC Medical Ethics (SSCI/SCIE indexed, Q2 of Chinese Academy of Sciences). From a moral psychological perspective and based on situational experiments and projection techniques, it conducted survey on 287 medical researchers in China. The results showed that medical researchers' creative performance positively relates to scientific misconduct, and moral licensing played a mediating role in the relationship between them. In addition, moral identity had a negative moderating effect on the mediating effect of moral licensing on creative performance and scientific misconduct. The findings provide theoretical and practical implications for the prevention of medical researchers' scientific misconduct.   

Figure 15: The conceptual model