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Ultralow frequency waves in the South Atlantic anomaly:Application of FY-3E observations

science China Earth sciences 2025年第3期68卷 943-952页

作者： Li LI Qiugang ZONG Xuzhi ZHOU Ying LIU Robert RANKIN Shan WANG Yongfu WANG Xiangqian YU Jie REN Zikang XIE Hong ZOU Yuguang YE Chao YUE School of Earth and Space Sciences Peking UniversityBeijing 100871China State Key Laboratory of Lunar and Planetary Science Macao University of Science and TechnologyMacao 999078China Department of Physics University of AlbertaEdmonton AB T6G 2G7Canada School of Geophysics and Information Technology China University of Geosciences(Beijing)Beijing 100083China

On 5 July 2021, the China FY-3E satellite was successfully launched, equipped with instruments to measure ultralow frequency waves(ULF) and charged particle populations deep within the magnetosphere. In this study, we report two ULF wave events observed by the FY-3E satellite, which are closely associated with magnetospheric substorms, in conjunction with observations from the Swarm satellite. We noticed a significant similarity between the ULF waves recorded by FY-3E and Swarm, indicating that these satellites captured the same wave events. The presence of a 180° phase shift across L shells and an oscillating field aligned Poynting flux suggest that the observed ULF waves exhibit characteristics of field line resonance(FLR).This work also characterizes essential differences in the behavior of ULF pulsations affected by the South Atlantic anomaly(SAA) in comparison to a conjugate region outside. Wave packets in the SAA region exhibit higher amplitudes than the pulsations in the northern hemisphere. This difference is likely influenced by the north-south asymmetry of the geomagnetic field and ionospheric conductivities, which, in turn, control the standing wave structure along the field line.

关键词： ULF waves SAA FY-3E Swarm north-south asymmetry

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Three-dimensional magnetic reconnection in complex multiple X-point configurations in an ancient solar-lunar terrestrial system

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Chinese physics B 2024年第3期33卷 488-495页

作者：何向磊毛傲华孙萌萌邹继同王晓钢 School of Physics Harbin Institute of TechnologyHarbin 150001China Laboratory for Space Environment and Materials Science Harbin Institute of TechnologyHarbin 150001China

Magnetic reconnection processes in three-dimensional(3D)complex field configurations have been investigated in different magneto-plasma systems in space,laboratory,and astrophysical ***-dimensional(2D)features of magnetic reconnection have been well developed and applied successfully to systems with symmetrical property,such as toroidal fusion plasmas and laboratory experiments with an axial *** in asymmetric systems,the 3D features are inevitably different from those in the 2D *** reconnection structures in multiple celestial body systems,particularly star-planet-Moon systems,bring fresh insights to the understanding of the 3D geometry of ***,we take magnetic reconnection in an ancient solar-lunar terrestrial magneto-plasma system as an example by using its crucial parameters approximately estimated already and also some specific applications in pathways for energy and matter transports among Earth,ancient Moon,and the interplanetary magnetic field(IMF).Then,magnetic reconnection of the ancient lunar-terrestrial magnetospheres with the IMF is investigated numerically in this *** a 3D simulation for the Earth-Moon-IMF system,topological features of complex magnetic reconnection configurations and dynamical characteristics of magnetic reconnection processes are *** is found that a coupled lunar-terrestrial magnetosphere is formed,and under various IMF orientations,multiple X-points emerge at distinct locations,showing three typical magnetic reconnection structures in such a geometry,i.e.,the X-line,the triple current sheets,and the A-B null *** results can conduce to further understanding of reconnection physics in 3D for plasmas in complex magnetic configurations,and also a possible mechanism for energy and matters transport in evolutions of similar astrophysical systems.

关键词： magnetic reconnection multiple X-points complex magneto-plasma system

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Research on Improvement of Time Synchronization Protocol in Telemetry Network System (TmNS)

Research on Improvement of Time Synchronization Protocol in ...

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2022 International Conference on Computing, Communication, Perception and Quantum technology, CCPQT 2022

作者： Qiu, Changquan Yuan, Yanrong Sun, Jinghua Xue, Zhichao Lan, Jinghui Science and Technology on Space Physics Laboratory Beijing China

ISBN: (数字)9781665470209

ISBN: (纸本)9781665470209

The standard Telemetry Network System(TmNS) has been officially incorporated into the IRIG 106-17 standard developed by the Range Instrument Group IRIG, a subsidiary of the RCC, in 2017 and has been gradually improved. TmNS brings new capabilities to the traditional telemetry system and represents the development direction of the next generation telemetry system. Time synchronization is the key technology of TmNS, which is the basis of wireless network connection between multiple test objects and multiple ground stations. In order to adapt to the situation of high packet loss rate of wireless link and high requirement of time synchronization accuracy, an improved time synchronization protocol algorithm is proposed and evaluated by simulation. © 2022 IEEE.

关键词： Synchronization

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Spin reorientation in easy-plane kagome ferromagnet Li_9Cr_3(P_2O_7)_3(PO_4)_2

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Chinese physics B 2023年第5期32卷 153-157页

作者：董元浩付盈刘以轩郝占阳王乐刘才邓可梅佳伟 Shenzhen Institute for Quantum Science and Engineering and Department of PhysicsSouthern University of Science and TechnologyShenzhen 518055China School of Physics Xi’an Jiaotong UniversityXi’an 710049China Department of Physics Southern University of Science and TechnologyShenzhen 518055China Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices Southern University of Science and TechnologyShenzhen 518055China

We report the successful growth and characterization of Li_9Cr_3(P_2O_7)_3(PO_4)_2single crystal,and investigate its magnetic properties under external magnetic fields via magnetization and heat capacity *** study reveals that Li_9Cr_3(P_2O_7)_3(PO_4)_2 is an easy-plane kagome ferromagnet with S=3/2,as evidenced by the Curie–Weiss temperature of 6 K which implies a ferromagnetic exchange coupling in the *** zero magnetic field,Li_9Cr_3(P_2O_7)_3(PO_4)_2 undergoes a magnetic transition at TC=2.7 K from a paramagnetic state to a ferromagnetically ordered state with the magnetic moment lying in the kagome *** applying a c-axis directional magnetic field to rotate the spin alignment from the kagome plane to the c-axis,we observe a reduction in the magnetic transition temperature as the field is *** construct a magnetic phase diagram as a function of temperature and magnetic field applied parallel to the c-axis of Li_9Cr_3(P_2O_7)_3(PO_4)_2 and find that the phase boundary is linear over a certain temperature *** that theoretically,the field-induced phase transition of the spin reorientation in the easy-plane ferromagnet can be viewed as the ferromagnetic magnon Bose–Einstein condensation(BEC),the phase boundary scaling of field-induced(B c)magnetic transition in Li_9Cr_3(P_2O_7)_3(PO_4)_2 can be described as the quasi-2D magnon BEC,which has been observed in other ferromagnetic materials such as K_2CuF_4.

关键词： kagome lattice flux method magnetic material spin-3/2

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Direct high-resolution X-ray imaging exploiting pseudorandomness

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Light(science & Applications) 2023年第5期12卷 776-788页

作者： KyeoReh Lee Jun Lim Su Yong Lee YongKeun Park Department of Physics Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea KAIST Institute for Health Science and Technology Korea Advanced Institute of Science and TechnologyDaejeon 34141Republic of Korea Pohang Accelerator Laboratory Pohang University of Science and TechnologyPohangKyungbuk 37637Republic of Korea Tomocube Inc Daejeon 34051Republic of Korea

Owing to its unique penetrating power and high-resolution capability,X-ray imaging has been an irreplaceable tool since its *** the significance,the resolution of X-ray imaging has largely been limited by the technical difficulties on X-ray lens *** lensless imaging methods have been proposed,but are yet relying on multiple measurements or additional constraints on measurements or *** we present coherent specklecorrelation imaging(CSI)using a designed X-ray *** has no prerequisites for samples or ***,from a single shot measurement,the complex sample field is retrieved based on the pseudorandomness of the speckle intensity pattern,ensured through a *** achieve a spatial resolution of 13.9 nm at 5.46 keV,beating the feature size of the diffuser used(300 nm).The high-resolution imaging capability is theoretically explained based on fundamental and practical *** expect the CSI to be a versatile tool for navigating the unexplored world of nanometer.

关键词： resolution speckle replace

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Structure-preserving algorithms for guiding center dynamics based on the slow manifold of classical Pauli particle

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Plasma science and technology 2024年第6期26卷 88-102页

作者：张若涵王正汹肖建元王丰 Key Laboratory of Materials Modification by Laser Ion and Electron BeamsSchool of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Department of Plasma Physics and Fusion Engineering University of Science and Technology of ChinaHefei 230026People’s Republic of China

The classical Pauli particle(CPP) serves as a slow manifold, substituting the conventional guiding center dynamics. Based on the CPP, we utilize the averaged vector field(AVF) method in the computations of drift orbits. Demonstrating significantly higher efficiency, this advanced method is capable of accomplishing the simulation in less than one-third of the time of directly computing the guiding center motion. In contrast to the CPP-based Boris algorithm, this approach inherits the advantages of the AVF method, yielding stable trajectories even achieved with a tenfold time step and reducing the energy error by two orders of magnitude. By comparing these two CPP algorithms with the traditional RK4 method, the numerical results indicate a remarkable performance in terms of both the computational efficiency and error elimination. Moreover, we verify the properties of slow manifold integrators and successfully observe the bounce on both sides of the limiting slow manifold with deliberately chosen perturbed initial conditions. To evaluate the practical value of the methods, we conduct simulations in non-axisymmetric perturbation magnetic fields as part of the experiments,demonstrating that our CPP-based AVF method can handle simulations under complex magnetic field configurations with high accuracy, which the CPP-based Boris algorithm lacks. Through numerical experiments, we demonstrate that the CPP can replace guiding center dynamics in using energy-preserving algorithms for computations, providing a new, efficient, as well as stable approach for applying structure-preserving algorithms in plasma simulations.

关键词： structure-preserving algorithm averaged vector field classical Pauli particle guiding center dynamics

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Research on Deep Neural Networks for Real-Time Detection and Tracking of Highly Dynamic Targets 5

Research on Deep Neural Networks for Real-Time Detection and...

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5th International Conference on Pattern Recognition and Artificial Intelligence, PRAI 2022

作者： Hanqing, Xue Xiaotian, Wang Kai, Xue Chao, Chen Hanyi, Zhang Na, Jin Science and Technology on Space Physics Laboratory Beijing China

ISBN: (数字)9781665499163

ISBN: (纸本)9781665499163

In recent years, artificial intelligence technology represented by deep learning has made major breakthroughs in the field of target recognition, and the application of intelligent target recognition capabilities to the aerospace field is an important direction for future development. However, artificial intelligence technology brings a huge amount of computation and high energy consumption to the aircraft while bringing the target perception capability. However, the aerospace field faces many challenges such as complex environmental interference conditions, lack of data samples, high dynamics, and strong real-time performance. In order to solve the problems above, we purpose a lightweight network which was realized by the separable convolution, ghost bottleneck and structures such as reverse residual modules with different lengths. We applied above purpose method to remote sensing image data. The results indicate that the accuracy of the algorithm is 4.7% higher than traditional lightweight algorithm. To validate the practicability under engineering background, we deployed purposed algorithm to Nvidia edge computing devices Jetson TX2. Experimental data show that our algorithm can achieve 10FPS. It meets the requirements of real-time and accuracy in aerospace applications and has high application value. The technologies described in this study can be used in radar image recognition, multi-modal image analysis, and aerospace intelligent target detection etc., which will effectively improve the intelligence level in the aerospace field and promote the development of equipment intelligence. © 2022 IEEE.

关键词： Deep neural networks

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Enhancing alkyne semi-hydrogenation through engineering metal-support interactions of Pd on oxides

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Nano Research 2024年第5期17卷 3707-3713页

作者： Yuefeng Wu Xiaotong Lu Pengfei Cui Wenyu Jia Jun Zhou Yuan Wang Hussain Zahid Yuxin Wu Muhammad Umer Rafique Xiong Yin Baoshan Li Leyu Wang Guolei Xiang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China College of Chemical Engineering Beijing University of Chemical TechnologyBeijing 100029China

Supported Pd catalysts show superior activities for olefin productions from alkynes through semi-hydrogenation reactions,but over-hydrogenation into alkanes highly decreases olefin *** phenylacetylene semi-hydrogenation as a model reaction,here we explore the optimization approaches toward better Pd catalysts for alkyne semi-hydrogenation through investigating support effect and metal-support *** results show that the states of Pd with supports can be tuned by varying oxide reducibility,loading ratios,and *** our system,0.06 wt.%Pd on rutile-TiO_(2) nanorods shows the highest activity owing to the synergistic effects of single-atoms and *** reducibility can change the filling degrees of Pd 4d orbitals through varying interfacial bonding strengths,which further affect catalytic activity and selectivity.

关键词： alkyne semi-hydrogenation support effect metal-support interaction Pd catalyst single-atom catalyst

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Influence of complicated faults on the differentiation and accumulation of in-situ stress in deep rock mass

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International Journal of Minerals,Metallurgy and Materials 2023年第5期30卷 791-801页

作者： Naigen Tan Renshu Yang Zhuoying Tan Beijing Key Laboratory of Urban Underground Space Engineering School of Civil and Resource EngineeringUniversity of Science and Technology BeijingBeijing 100083China

High geostress will become a normality in the deep because in-situ stress rises linearly with *** geological structure grows immensely intricate as depth ***,small fractures,and joint fissures are widely *** objective of this paper is to identify geostress anomalies at a variety of locations near faults and to demonstrate their accumulation *** tests were conducted in seven deep *** conducted a test at a drilling depth of over one thousand meters to reveal and quantify the influence of faults on in-situ stresses at the hanging wall,footwall,between faults,end of faults,junction of faults,and far-field of *** effect of fault sites and characteristics on the direction and magnitude of stresses has been investigated and compared to test *** accumulation heterogeneity of stresses near faults was illustrated by a three-dimensional numerical simulation,which is utilized to explain the effect of faults on the accumulation and differentiation of in-situ *** to regional tectonics and faulting,the magnitude,direction,and stress regime are all extremely *** concentration degree of geostress and direction change will vary with the location of faults near faults,but the magnitude and direction of in-situ stress conform to regional tectonic stress at a distance from the *** focal mechanism solution has been verified using historical seismic ground motion *** results demonstrate that the degree of stress differentiation varies according to the fault attribute and its *** in stress differentiation and its ratio from strong to weak occur between faults,intersection,footwall,end of faults,and hanging wall;along with the sequence of orientation is the footwall,between faults,the end of faults,intersection,and hanging *** work sheds new light on the fault-induced stress accumulation and orientation shift mechanisms across the entire cycle.

关键词： fault geostress in deep magnitude and direction of geostress mining dynamic hazards stress accumulation mining optimization

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Skyrmion motion induced by spin-waves on magnetic nanotubes

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Chinese physics B 2024年第10期33卷 413-418页

作者： Tijjani Abdulrazak Xuejuan Liu Zhenyu Wang Yunshan Cao Peng Yan School of Physics and State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054China Department of Physics Bayero UniversityKano-700006Nigeria School of Healthcare Technology Chengdu Neusoft UniversityChengdu 611844China

We investigate the skyrmion motion driven by spin waves on magnetic nanotubes through micromagnetic *** key results include demonstrating the stability and enhanced mobility of skyrmions on the edgeless nanotube geometry,which prevents destruction at boundaries—a common issue in planar *** explore the influence of the damping coefficient,amplitude,and frequency of microwaves on skyrmion dynamics,revealing a non-uniform velocity profile characterized by acceleration and deceleration *** results show that the skyrmion Hall effect is significantly modulated on nanotubes compared to planar models,with specific dependencies on the spin-wave *** findings provide insights into skyrmion manipulation for spintronic applications,highlighting the potential for high-speed and efficient information transport in magnonic devices.

关键词： ferromagnetic magnetic nanotube Mumax3 software skyrmion spin-wave

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