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Physical mechanism of secondary-electron emission in Si wafers

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Chinese Physics B 2024年第4期33卷 677-681页

作者：赵亚楠孟祥兆彭淑婷苗光辉高玉强彭斌崔万照胡忠强 State Key Laboratory for Manufacturing Systems Engineering Electronic Materials Research LaboratoryKey Laboratory of the Ministry of EducationEngineering Research Center of Spin Quantum Sensor ChipsUniversities of Shaanxi ProvinceSchool of Electronic Science and EngineeringXi'an Jiaotong UniversityXi'an 710049China College of Aeronautics Nanjing University of Aeronautics and AstronauticsNanjing 210016China national Key Laboratory of Science and technology on space Microwave China Academy of Space TechnologyXi'an 710100China Department of Physics School of Physics and Electronic InformationAnhui Normal UniversityWuhu 241000China

CMOS-compatible RF/microwave devices,such as filters and amplifiers,have been widely used in wireless communication ***,secondary-electron emission phenomena often occur in RF/microwave devices based on silicon(Si)wafers,especially in the high-frequency *** this paper,we have studied the major factors that influence the secondary-electron yield(SEY)in commercial Si wafers with different doping *** show that the SEY is suppressed as the doping concentration increases,corresponding to a relatively short effective escape depthλ.Meanwhile,the reduced narrow band gap is beneficial in suppressing the SEY,in which the absence of a shallow energy band below the conduction band will easily capture electrons,as revealed by first-principles ***,the new physical mechanism combined with the effective escape depth and band gap can provide useful guidance for the design of integrated RF/microwave devices based on Si wafers.

关键词： secondary-electron yield doping concentration escape depth Si wafer

Scientific objectives and payload configuration of the Chang'E-7 mission

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national Science Review 2024年第2期11卷 285-300页

作者： Chi Wang Yingzhuo Jia Changbin Xue Yangting Lin Jianzhong Liu Xiaohui Fu Lin Xu Yun Huang Yufen Zhao Yigang Xu Rui Gao Yong Wei Yuhua Tang Dengyun Yu Yongliao Zou State Key Laboratory of space Weather National Space Science Center Chinese Academy of Sciences national space Science center Chinese Academy of Sciences Institute of Geology and Geophysics Chinese Academy of Sciences Institute of Geochemistry Chinese Academy of Sciences Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment School of Space Science and Physics Institute of Space SciencesShandong University Institute of Drug Discovery technology Ningbo University State Key Laboratory of Isotope Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences School of Earth Science and Engineering Sun Yat-sen University Lunar Exploration and space Engineering center China Aerospace Science and technology Corporation

As the cornerstone mission of the fourth phase of the Chinese Lunar Exploration Program, Chang'E-7(CE-7) was officially approved, and implementation started in 2022, including a main probe and a communication relay satellite. The main probe, consisting of an orbiter, a lander, a rover and a mini-flying probe, is scheduled to be launched in 2026. The lander will land on Shackleton crater's illuminated rim near the lunar south pole, along with the rover and mini-flying probe. The relay satellite(named Queqiao-2) will be launched in February 2024 as an independent mission to support relay communication during scientific exploration undertaken by Chang'E-4, the upcoming Chang'E-6 in 2024 and subsequent lunar *** CE-7 mission is mainly aimed at scientific and resource exploration of the lunar south pole. We present CE-7's scientific objectives, the scientific payloads configuration and the main functions for each scientific payload with its key technical specifications.

关键词： Chang’ E-7 scientific objectives scientific payloads

Optimal confrontation position selecting games model and its application to one-on-one air combat

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Defence technology（防务技术） 2024年第1期31卷 417-428页

作者： Zekun Duan Genjiu Xu Xin Liu Jiayuan Ma Liying Wang School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'an 710072China International Joint research center on Operations research Optimization and Artificial IntelligenceXi'an 710129China AVIC Xi’an Aeronautics Computing Technique research Institute Xi'an 710065China Unmanned System research Institute Northwestern Polytechnical UniversityXi'an 710072China

In the air combat process,confrontation position is the critical factor to determine the confrontation situation,attack effect and escape probability of ***,selecting the optimal confrontation position becomes the primary goal of maneuver *** taking the position as the UAV’s maneuver strategy,this paper constructs the optimal confrontation position selecting games(OCPSGs)*** the OCPSGs model,the payoff function of each UAV is defined by the difference between the comprehensive advantages of both sides,and the strategy space of each UAV at every step is defined by its accessible space determined by the *** we design the limit approximation of mixed strategy Nash equilibrium(LAMSNQ)algorithm,which provides a method to determine the optimal probability distribution of positions in the strategy *** the simulation phase,we assume the motions on three directions are independent and the strategy space is a cuboid to simplify the *** simulations are performed to verify the feasibility,effectiveness and stability of the algorithm.

关键词： Unmanned aerial vehicles(UAVs) Air combat Continuous strategy space Mixed strategy Nash equilibrium

Multi-Scale X-Ray Imaging Technologies for Rechargeable Batteries

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Chinese Physics Letters 2024年第8期41卷 107-120页

作者： Zihan Xu Hanwen An Jiajun Wang MOE Engineering research center for Electrochemical Energy Storage and Carbon Neutrality in Cold Regions School of Chemistry and Chemical EngineeringHarbin Institute of Technology Harbin 150001China State Key Laboratory of space Power Sources Harbin Institute of TechnologyHarbin 150001China Chongqing research Institute of HIT Chongqing 401135China

The rapid advancement in electric vehicles and electrochemical energy storage technology has raised the demands placed on rechargeable *** is essential to comprehend the operational principles and degradation mechanisms of batteries across multiple scales to propel the research on rechargeable batteries for the next generation ***,phase information,and lattice of energy materials in both two dimensions and three dimensions can be intuitively obtained through the utilization of x-ray imaging ***,x-ray imaging technology is increasingly gaining attention due to its non-destructive nature and high penetrative capability,enabling in situ experiments and multi-scale spatial *** this review,we initially overview the basic principles and characteristics of several key x-ray imaging *** x-ray imaging technology is tailored to specific application ***,examples of multi-scale implementations of x-ray imaging technologies in the field of rechargeable batteries are *** review is anticipated to augment the comprehension of readers for x-ray imaging techniques as well as to stimulate the development of novel concepts and approaches in rechargeable battery research.

关键词： battery dimensions charge

Understanding adversarial attacks on observations in deep reinforcement learning

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Science China(Information Sciences) 2024年第5期67卷 69-83页

作者： You QIAOBEN Chengyang YING Xinning ZHOU Hang SU Jun ZHU Bo ZHANG Department of Computer Science and technology Beijing National Research Center for Information Science and Technology Tsinghua-Bosch Joint Center for Machine Learning Institute for Artificial Intelligence Tsinghua University Peng Cheng Laboratory

Deep reinforcement learning models are vulnerable to adversarial attacks that can decrease the cumulative expected reward of a victim by manipulating its observations. Despite the efficiency of previous optimization-based methods for generating adversarial noise in supervised learning, such methods might not achieve the lowest cumulative reward since they do not generally explore the environmental ***, a framework is provided to better understand the existing methods by reformulating the problem of adversarial attacks on reinforcement learning in the function space. The reformulation approach adopted herein generates an optimal adversary in the function space of targeted attacks, repelling them via a generic two-stage framework. In the first stage, a deceptive policy is trained by hacking the environment and discovering a set of trajectories routing to the lowest reward or the worst-case performance. Next, the adversary misleads the victim to imitate the deceptive policy by perturbing the observations. Compared to existing approaches, it is theoretically shown that our adversary is strong under an appropriate noise level. Extensive experiments demonstrate the superiority of the proposed method in terms of efficiency and effectiveness, achieving state-of-the-art performance in both Atari and MuJoCo environments.

关键词： deep learning reinforcement learning adversarial robustness adversarial attack

High-precision temperature retrieval algorithm and verification for mesospheric airglow spectrum photometer

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Science China Earth Sciences 2024年第5期67卷 1639-1651页

作者： Shuqi NIU Haiyang GAO Zhaoai YAN Ke REN Leilei KOU Baichuan JIANG Lingbin BU Key Open Laboratory of Aerosol and Cloud Precipitation of China Meteorological Administration Nanjing 210044China School of Atmospheric Physics Nanjing University of Information Science and TechnologyNanjing 210044China national space Science center Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China

Photometric technology,characterized by its compact structure and relatively high stability,finds wide application in measuring airglow *** instrumentation is anticipated to assume a pivotal role as the primary equipment for extensive network observations of middle and upper atmospheric temperatures in China,thereby providing crucial support for space environmental monitoring and atmospheric dynamic ***,susceptibility to various factors such as instrument inconsistency,variability in observation conditions,and alterations in the background atmospheric environment across different stations poses a challenge,potentially resulting in data inconsistencies in network *** response to these challenges,we propose a multiple-parameter iterative inversion(MPII)algorithm for temperature retrieval based on a mesospheric airglow spectrum photometer(MASP)developed by our research *** algorithm accurately identifies the center of the image circle,corrects image distortion,and thereby obtains an accurate synthetic spectrum reflective of actual *** encompasses five adjustable parameters:sky background light,atmospheric temperature,filter temperature,optical system focal length,and degree of synthetic spectrum *** to traditional methods,significant enhancements in the accuracy of the inverted temperature are *** validate the effectiveness of the MPII algorithm,we conducted combined active and passive remote sensing synchronous measurements using MASP in conjunction with a sodium fluorescence Doppler lidar developed by the national space Science *** utilizing the lidar temperature as a reference,atmospheric background radiation is mitigated from the MASP data,and the temperature is inverted using the MPII *** analysis with the traditional method reveals that temperatures calculated by the MPII algorithm exhibit better consistency than those observed by the lidar.

关键词： Temperature inversion Airglow spectrum photometer Rotational spectral lines Sodium fluorescence Doppler lidar Comparative observations

Boson star superradiance

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 69-78页

作者： He-Yu Gao Paul M.Saffin Yi-Jie Wang Qi-Xin Xie Shuang-Yong Zhou School of Physical Sciences University of Science and Technology of ChinaHefei 230026China School of Physics and Astronomy University of NottinghamUniversity ParkNottingham NG72RDUK Interdisciplinary center for Theoretical Study University of Science and Technology of ChinaHefei 230026China Peng Huanwu center for Fundamental Theory Hefei 230026China

Recently,it has been realized that in some systems internal space rotation can induce energy amplification for scattered waves,similar to rotation in real *** particularly,it has been shown that energy extraction is possible for a Q-ball,a stationary non-topological soliton that is coherently rotating in its field *** this paper,we generalize the analysis to the case of boson stars,and show that the same energy extraction mechanism still works for boson stars.

关键词： superradiance boson star field space rotation

Statistical study of magnetic holes in the upstream region of Mercury’s bow shock

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Earth and Planetary Physics 2024年第2期8卷 326-337页

作者： GuoQiang Wang SuDong Xiao MingYu Wu YuanQiang Chen TieLong Zhang Institute of space Science and Applied technology Harbin Institute of TechnologyShenzhen 518055China Shenzhen Key Laboratory of Numerical Prediction for space Storm Harbin Institute of TechnologyShenzhen 518055China Mengcheng national Geophysical Observatory University of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences center for Excellence in Comparative Planetology Hefei 230026China space research Institute Austrian Academy of SciencesGrazAustria

Magnetic holes are magnetic depression structures that exist widely in many plasma *** magnetic holes with durations of>1 s in the solar wind at Mercury’s orbit have drawn much attention,but the properties of the magnetic holes with shorter durations are still ***,we investigate the magnetic holes with durations of 0.1-100 s in the upstream region of Mercury’s bow shock based on observations by the MESSENGER(MErcury Surface,space ENvironment,GEochemistry,and Ranging)*** can be divided into two groups according to the distribution of their duration:small-duration magnetic holes(SDMHs,0.6 s).The duration of each group approximately obeys a log-normal distribution with a median of~0.25 s and 3 s,*** 1.7%(32.6%)of the SDMHs(LDMHs)reduce the magnetic field strength by more than 50%.For both groups,some structures have a linear or quasi-linear polarization,whereas others have an elliptical *** magnetic hole events in both groups tend to have a higher rate of occurrence when the interplanetary magnetic field strength is *** occurrence rates are also affected by Mercury’s foreshock,which can increase(decrease)the occurrence rate of the SDMHs(LDMHs).This finding suggests that Mercury’s foreshock might be one source of the SDMHs and that the foreshock can destroy some *** observations suggest that a new group of magnetic holes with durations of<0.6 s exist in the upstream region of Mercury’s bow shock.

关键词： magnetic hole solar wind Mercury foreshock

Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei Lin Yechun Ding Yongsheng Wang Peng Li Yanpeng Zhang Feng Yun Feng Li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State Lighting Engineering research center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean *** report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space *** the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic *** observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space