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A Non-Stop Double Buffering Mechanism for Dataflow Architecture

Journal of Computer Science & Technology 2018年第1期33卷 145-157页

作者： Xu Tan Xiao-Wei Shen Xiao-Chun Ye Da Wang Dong-Rui Fan Lunkai Zhang Wen-Ming Li Zhi-Min Zhang Zhi-Min Tang State Key Laboratory of Computer Architecture Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China School of Computer and Control Engineering University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Mathematical Engineering and Advanced Computing Wuxi 214125 China Department of Computer Science The University of Chicago Chicago IL 60637 U.S.A.

Double buffering is an effective mechanism to hide the latency of data transfers between on-chip and off-chip memory. However, in dataflow architecture, the swapping of two buffers during the execution of many tiles decreases the performance because of repetitive filling and draining of the dataflow accelerator. In this work, we propose a non-stop double buffering mechanism for dataflow architecture. The proposed non-stop mechanism assigns tiles to the processing element array without stopping the execution of processing elements through optimizing control logic in dataflow architecture. Moreover, we propose a work-flow program to cooperate with the non-stop double buffering mechanism. After optimizations both on control logic and on work-flow program, the filling and draining of the array needs to be done only once across the execution of all tiles belonging to the same dataflow graph. Experimental results show that the proposed double buffering mechanism for dataftow architecture achieves a 16.2% average efficiency improvement over that without the optimization.

关键词： non-stop double buffering dataflow architecture high-performance computing

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Measurement-Device-Independent Quantum key Distribution with Leaky Sources

arXiv

引用

arXiv 2020年

作者： Wang, Weilong Tamaki, Kiyoshi Curty, Marcos EI Telecomunicación Department of Signal Theory and Communications University of Vigo VigoE-36310 Spain State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou Henan450001 China Henan Key Laboratory of Network Cryptography Technology ZhengzhouHenan450001 China Faculty of engineering University of Toyama Gofuku 3190 Toyama930-8555 Japan

Measurement-device-independent quantum key distribution (MDI-QKD) can remove all detection side-channels from quantum communication systems. The security proofs require, however, that certain assumptions on the sources are satisfied. This includes, for instance, the requirement that there is no information leakage from the transmitters of the senders, which unfortunately is very difficult to guarantee in practice. In this paper we relax this unrealistic assumption by presenting a general formalism to prove the security of MDI-QKD with leaky sources. With this formalism, we analyze the finite-key security of two prominent MDI-QKD schemes – a symmetric three-intensity decoy-state MDI-QKD protocol and a four-intensity decoy-state MDI-QKD protocol – and determine their robustness against information leakage from both the intensity modulator and the phase modulator of the transmitters. Our work shows that MDI-QKD is feasible within a reasonable time frame of signal transmission given that the sources are sufficiently isolated. Thus, it provides an essential reference for experimentalists to ensure the security of experimental implementations of MDI-QKD in the presence of information leakage. Copyright © 2020, The Authors. All rights reserved.

关键词： Quantum cryptography

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A Format Protection Method of Greybox Fuzzing 19

A Format Protection Method of Greybox Fuzzing

引用

19th IEEE International Conference on Communication Technology, ICCT 2019

作者： Zhao, Shibin Zhou, Tianyang Duan, Xiaoli Lin, Hongyang Ying, Xinlei Shi, Qibo Peng, Jianshan State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001 China China United Network Communications Group Co. Ltd Shanxi Yuncheng Branch Yuncheng044000 China Ant-financial Light-Year Security Lab hangzhou310000 China

ISBN: (纸本)9781728105352

Greybox fuzzing, which can fuzz without knowledge of the format, is one of the most advanced fuzzing techniques. However, the lack of format knowledge makes the test cases' format messy as the fuzzing proceeds and reduces the effectiveness of fuzzing. In this paper, we introduce a format protection method that can protect the format of test cases during greybox fuzzing. Based on prior knowledge, the Naive Bayes classifier is applied to achieve a format check method, which is used to improve the favourite seed selection process and induce the position of variation. The experiment results indicate that this method not only has a higher code coverage ratio and more unique crashes in less time than other fuzzers but also maintains the invalid format ratio at a low level. 24 previously unreported CVEs were exposed. © 2019 IEEE.

关键词： Classifiers

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Detection of two TeV gamma-ray outbursts from NGC 1275 by LHAASO

引用

Monthly Notices of the Royal Astronomical Society 2025年第2期540卷 1860–1869页

作者： Cao, Zhen Aharonian, F Axikegu Bai, Y X Bao, Y W Bastieri, D Bi, X J Bi, Y J Bian, W Bukevich, A V Cao, Q Cao, W Y Cao, Z Chang, J Chang, J F Chen, A M Chen, E S Chen, H X Chen, L Chen, M J Chen, M L Chen, Q H Chen, S Chen, S H Chen, S Z Chen, T L Chen, Y Cheng, N Cheng, Y D Chu, M C Cui, M Y Cui, S W Cui, X H Cui, Y D Dai, B Z Dai, H L Dai, Z G Danzengluobu Dong, X Q Duan, K K Fan, J H Fan, Y Z Fang, J Fang, J H Fang, K Feng, C F Feng, H Feng, L Feng, S H Feng, X T Feng, Y Feng, Y L Gabici, S Gao, B Gao, C D Gao, Q Gao, W Gao, W K Ge, M M Ge, T T Geng, L S Giacinti, G Gong, G H Gou, Q B Gu, M H Guo, F L Guo, J Guo, X L Guo, Y Q Guo, Y Y Han, Y A Hannuksela, O A Hasan, M He, H H He, H N He, J Y He, Y Hor, Y K Hou, B W Hou, C Hu, H B Hu, Q Hu, S C Huang, C Huang, D H Huang, T Q Huang, W J Huang, X T Huang, X Y Huang, Y Huang, Y Y Ji, X L Jia, H Y Jia, K Jiang, H B Jiang, K Jiang, X W Jiang, Z J Jin, M Kang, M M Karpikov, I Khangulyan, D Kuleshov, D Kurinov, K Li, B B Li, C M Li, C Li, D Li, F Li, H B Li, H C Li, J Li, K Li, S D Li, W L Li, X R Li, X Li, Y Z Li, Z Liang, E W Liang, Y F Lin, S J Liu, B Liu, C Liu, D Liu, D B Liu, H Liu, H D Liu, J Liu, J L Liu, M Y Liu, R Y Liu, S M Liu, W Liu, Y Liu, Y N Luo, Q Luo, Y Lv, H K Ma, B Q Ma, L L Ma, X H Mao, J R Min, Z Mitthumsiri, W Mu, H J Nan, Y C Neronov, A Ng, K C Y Ou, L J Pattarakijwanich, P Pei, Z Y Qi, J C Qi, M Y Qiao, B Q Qin, J J Raza, A Ruffolo, D Sáiz, A Saeed, M Semikoz, D Shao, L Shchegolev, O Sheng, X D Shu, F W Song, H C Stenkin, Yu V Stepanov, V Su, Y Sun, D X Sun, Q N Sun, X N Sun, Z B Takata, J Tam, P H T Tang, Q W Tang, R Tang, Z B Tian, W W Wan, L H Wang, C Wang, C B Wang, G W Wang, H G Wang, H H Wang, J C Wang, K Wang, L P Wang, L Y Wang, P H Wang, R Wang, W Wang, X G Wang, X Y Wang, Y Wang, Y D Wang, Y J Wang, Z H Wang, Z X Wang, Z Wei, D M Wei, J J Wei, Y J Wen, T Wu, C Y Wu, H R Wu, Q W Wu, S Wu, X F Wu, Y S Xi, S Q Xia, J Xiang, G M Xiao, D X Xiao, G Xin, Y L Xing, Y Xiong, D R Xiong, Z Xu, D L Xu, R F Xu, R X Xu, W L Xue, L Yan, D H Yan, J Key Laboratory of Particle Astrophysics & Experimental Physics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences 100049 Beijing China University of Chinese Academy of Sciences 100049 Beijing China TIANFU Cosmic Ray Research Center Chengdu Sichuan China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 D-69029 Heidelberg Germany School of Physical Science and Technology & School of Information Science and Technology Southwest Jiaotong University Chengdu 610031 Sichuan China School of Astronomy and Space Science Nanjing University Nanjing 210023 Jiangsu China Center for Astrophysics Guangzhou University Guangzhou 510006 Guangdong China Tsung-Dao Lee Institute & School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Institute for Nuclear Research of Russian Academy of Sciences Moscow 117312 Russia Hebei Normal University Shijiazhuang 050024 Hebei China University of Science and Technology of China Hefei 230026 Anhui China Key Laboratory of Dark Matter and Space Astronomy & Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210023 Jiangsu China State Key Laboratory of Particle Detection and Electronics China Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou 311121 Zhejiang China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China School of Physics and Astronomy Yunnan University Kunming 650091 Yunnan China Key Laboratory of Cosmic Rays (Tibet University) Ministry of Education Lhasa 850000 Tibet China Department of Physics The Chinese University of Hong Kong Shatin New Territories Hong Kong China Key Laboratory of Radio Astronomy and Technology National Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China School of Physics and A

The Water Cherenkov Detector Array (WCDA) is one of the components of Large High Altitude Air Shower Observatory (LHAASO) and can monitor any sources over two-thirds of the sky for up to 7 h per day with >98 per cent duty cycle. In this work, we report the detection of two outbursts of the Fanaroff–Riley I radio galaxy NGC 1275 that were detected by LHAASO-WCDA between 2022 November and 2023 January with statistical significance of 5.2σand 8.3σ⁠. The observed spectral energy distribution in the range from 500 GeV to 3 TeV is fitted by a power law with the best-fitting spectral index ofα=−3.37±0.52and−3.35±0.29⁠, respectively. The outburst flux above 0.5 TeV was (⁠4.55±4.21)×10−11cm−2s−1and (⁠3.45±1.78)×10−11cm−2s−1⁠, corresponding to 60 per cent and 45 per cent of Crab Nebula flux, respectively. Variation analysis reveals the variability time-scale of days at the TeV energy band. A simple test by one-zone synchrotron self-Compton model reproduces the data in the gamma-ray band well.

关键词： methods: data analysis methods: statistical galaxies: active galaxies: jets gamma-rays: general

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Dark Matter Search with a Resonantly-Coupled Hybrid Spin System

arXiv

引用

arXiv 2023年

作者： Wei, Kai Xu, Zitong He, Yuxuan Ma, Xiaolin Heng, Xing Huang, Xiaofei Quan, Wei Ji, Wei Liu, Jia Wang, Xiao-Ping Budker, Dmitry Fang, Jiancheng School of Instrumentation Science and Opto-electronics Engineering Beihang University Beijing100191 China Hangzhou Extremely Weak Magnetic Field Major Science and Technology Infrastructure Research Institute Hangzhou310051 China Hefei National Laboratory Hefei230088 China School of Physical and Mathematical Sciences Nanyang Technological University Singapore639798 Singapore School of Physics State Key Laboratory of Nuclear Physics and Technology Peking University Beijing100871 China Johannes Gutenberg University Mainz55128 Germany Helmholtz-Institute GSI Helmholtzzentrum fur Schwerionenforschung Mainz55128 Germany Center for High Energy Physics Peking University Beijing100871 China School of Physics Beihang University Beijing100191 China Beijing Key Laboratory of Advanced Nuclear Materials and Physics Beihang University Beijing100191 China Department of Physics University of California at Berkeley BerkeleyCA94720-7300 United States

Recent advances in tabletop quantum sensor technology have enabled searches for nongravitational interactions of dark matter (DM). Traditional axion DM experiments rely on sharp resonance, resulting in extensive scanning time to cover a wide mass range. In this work, we present a broadband approach in an alkali-21Ne spin system. We identify two distinct hybrid spin-coupled regimes: a self-compensation (SC) regime at low frequencies and a hybrid spin resonance (HSR) regime at higher frequencies. By utilizing these two distinct regimes, we significantly enhance the bandwidth of 21Ne nuclear spin compared to conventional nuclear magnetic resonance, while maintaining competitive sensitivity. We present a comprehensive broadband search for axion-like dark matter, covering 5 orders of magnitude of Compton frequencies range within [10−2, 103] Hz. We set new constraints on the axion dark matter interactions with neutrons and protons, accounting for the effects of DM stochasticity. For the axion-neutron coupling, our results reach a low value of |gann| ≤ 3 ×10−10 in the frequency range [2 ×10−2, 4] Hz surpassing astrophysical limits and providing the strongest laboratory constraints in the [10, 100] Hz range. For the axion-proton coupling, we offer the best terrestrial constraints for the frequency ranges [2 ×10−2, 5] Hz and [16, 7 ×102] Hz. Copyright © 2023, The Authors. All rights reserved.

关键词： Dark Matter

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Observations of cosmic-ray Sun’s shadow with LHAASO-WCDA 38

Observations of cosmic-ray Sun’s shadow with LHAASO-WCDA

引用

38th International Cosmic Ray Conference, ICRC 2023

作者： Cui, Ming-Yang Xia, Jie He, Jia-Yin Shi, Guang-Lu Feng, Li Yuan, Qiang Zhang, Yi Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Q. Cao, W.Y. Cao, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, Liang Chen, Lin Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu della Volpe, D. Dong, X.Q. Duan, K.K. Fan, J.H. Fan, Y.Z. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gabici, S. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.Y. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, D.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Kurinov, K. Li, B.B. Li, Cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. Li, W.L. Li, X.R. Li, Xin Li, Y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. Nan, Y.C. Neronov, A. Ou, Z.W. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Qi, Y.Q. Qiao, B.Q. Qin, J.J. Ruffolo, D. Sáiz, A. Semikoz, D. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shu, F.W. Song, H.C. Key Laboratory of Dark Matter and Space Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China School of Astronomy and Space Science University of Science and Technology of China Hefei230026 China Key Laboratory of Particle Astrophyics & Experimental Physics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China TIANFU Cosmic Ray Research Center Sichuan Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place Dublin 2 Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg69029 Germany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Anhui Hefei230026 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiaotong University Sichuan Chengdu610031 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Hebei Normal University Hebei Shijiazhuang050024 China Key Laboratory of Dark Matter and Space Astronomy Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Cosmic Rays [Tibet University Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Physics and Astronomy Sun Yat-sen University Zhuhai519000 China School of Physics Guangdong Guangzhou510275 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen Unive

During the propagation of cosmic rays (CRs) in the solar system, they are blocked by the Sun and deflected by the magnetic field, resulting in a shadow on the celestial map. As CRs travel from the vicinity of the Sun to the Earth, they encounter deflection from the coronal magnetic field (CMF), the interplanetary magnetic field (IMF), and finally the geomagnetic field (GMF). The extent of deflection is determined by the magnetic field’s intensity, direction, and energy of the CRs. Variations in the magnetic field cause corresponding changes in the position and size of the Sun’s shadow. By observing the Sun’s shadow of CRs, we can investigate the magnetic fields between the Sun and the Earth, complementing other measurements on these magnetic fields. Furthermore, it serves as a means to validate magnetic field models. The Large High Altitude Air Shower Observatory (LHAASO) is a new generation cosmic-ray and gamma-ray experiment in Daocheng, western China. With a vast Water Cherenkov Detector Array (WCDA) spanning 78,000 m2, LHAASO can successfully observe the significant Sun’s shadow within just a few days. Our study uses the WCDA to measure the Sun’s shadow effect caused by CRs over multiple Carrington rotation periods. Subsequently, we compare these results with simulations based on different magnetic field models. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Cosmic rays

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Highlight of LHAASO science results on PeVatrons 38

Highlight of LHAASO science results on PeVatrons

引用

38th International Cosmic Ray Conference, ICRC 2023

作者： Wu, Sha Chen, Songzhan Cao, Zhen Aharonian, F. An, Q. Axikegu Bai, Y.X. Bao, Y.W. Bastieri, D. Bi, X.J. Bi, Y.J. Cai, J.T. Cao, Q. Cao, W.Y. Cao, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, Liang Chen, Lin Chen, Long Chen, M.J. Chen, M.L. Chen, Q.H. Chen, S.H. Chen, S.Z. Chen, T.L. Chen, Y. Cheng, N. Cheng, Y.D. Cui, M.Y. Cui, S.W. Cui, X.H. Cui, Y.D. Dai, B.Z. Dai, H.L. Dai, Z.G. Danzengluobu della Volpe, D. Dong, X.Q. Duan, K.K. Fan, J.H. Fan, Y.Z. Fang, J. Fang, K. Feng, C.F. Feng, L. Feng, S.H. Feng, X.T. Feng, Y.L. Gabici, S. Gao, B. Gao, C.D. Gao, L.Q. Gao, Q. Gao, W. Gao, W.K. Ge, M.M. Geng, L.S. Giacinti, G. Gong, G.H. Gou, Q.B. Gu, M.H. Guo, F.L. Guo, X.L. Guo, Y.Q. Guo, Y.Y. Han, Y.A. He, H.H. He, H.N. He, J.Y. He, X.B. He, Y. Heller, M. Hor, Y.K. Hou, B.W. Hou, C. Hou, X. Hu, H.B. Hu, Q. Hu, S.C. Huang, D.H. Huang, T.Q. Huang, W.J. Huang, X.T. Huang, X.Y. Huang, Y. Huang, Z.C. Ji, X.L. Jia, H.Y. Jia, K. Jiang, K. Jiang, X.W. Jiang, Z.J. Jin, M. Kang, M.M. Ke, T. Kuleshov, D. Kurinov, K. Li, B.B. Li, Cheng Li, Cong Li, D. Li, F. Li, H.B. Li, H.C. Li, H.Y. Li, J. Li, Jian Li, Jie Li, K. Li, W.L. Li, W.L. Li, X.R. Li, Xin Li, Y.Z. Li, Zhe Li, Zhuo Liang, E.W. Liang, Y.F. Lin, S.J. Liu, B. Liu, C. Liu, D. Liu, H. Liu, H.D. Liu, J. Liu, J.L. Liu, J.Y. Liu, M.Y. Liu, R.Y. Liu, S.M. Liu, W. Liu, Y. Liu, Y.N. Lu, R. Luo, Q. Lv, H.K. Ma, B.Q. Ma, L.L. Ma, X.H. Mao, J.R. Min, Z. Mitthumsiri, W. Mu, H.J. Nan, Y.C. Neronov, A. Ou, Z.W. Pang, B.Y. Pattarakijwanich, P. Pei, Z.Y. Qi, M.Y. Qi, Y.Q. Qiao, B.Q. Qin, J.J. Ruffolo, D. Sáiz, A. Semikoz, D. Shao, C.Y. Shao, L. Shchegolev, O. Sheng, X.D. Shu, F.W. Song, H.C. Stenkin, Yu.V. Stepanov, V. Su, Y. Sun, Q.N. Sun, X.N. Sun, Z.B. Tam, P.H.T. Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China Key Laboratory of Particle Astrophysics Experimental Physics Division Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing100049 China University of Chinese Academy of Sciences Beijing100049 China TIANFU Cosmic Ray Research Center Sichuan Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place Dublin 2 Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg69029 Germany State Key Laboratory of Particle Detection and Electronics China University of Science and Technology of China Anhui Hefei230026 China School of Physical Science and Technology School of Information Science and Technology Southwest Jiaotong University Sichuan Chengdu610031 China School of Astronomy and Space Science Nanjing University Jiangsu Nanjing210023 China Center for Astrophysics Guangzhou University Guangdong Guangzhou510006 China Hebei Normal University Hebei Shijiazhuang050024 China Key Laboratory of Dark Matter and Space Astronomy Key Laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Jiangsu Nanjing210023 China Tsung-Dao Lee Institute School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Key Laboratory for Research in Galaxies and Cosmology Shanghai Astronomical Observatory Chinese Academy of Sciences Shanghai200030 China Key Laboratory of Cosmic Rays Tibet University Ministry of Education Tibet Lhasa850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Physics and Astronomy Sun Yat-sen University Zhuhai519000 China School of Physics Sun Yat-sen University Guangdong Guangzhou510275 China Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen University Zhuhai519000 China School of Physics and Astronomy Yunnan University Yunnan

The observation of ultra-high energy (UHE, E>100 TeV) gamma-ray sources plays a crucial role in identifying Galactic PeV accelerators, also known as PeVatrons. The Large High Altitude Air Shower Observatory (LHAASO) is a large hybrid extensive air shower array, constructed at Haizi Mountain, 4410 m a.s.l., in China. With its wide field of view and high sensitivity, LHAASO is an ideal instrument for the detection and study of PeVatrons within our Galaxy. Since July 2021, the whole LHAASO detector array has been completed and operated in good states. Through an all-sky survey, we have observed ultra-high energy gamma-ray emissions in 43 regions associated with pulsars, supernova remnants (SNR), young star clusters, and other celestial objects. In this proceeding, we will present the results obtained from representative gamma-ray sources and discuss our observations of diffuse gamma-ray emissions along the Galactic plane. © Copyright owned by the author(s) under the terms of the Creative Commons.

关键词： Supernovae

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Creation of magnetic skyrmions in two-dimensional van der Waals ferromagnets by lattice distortion

引用

Materials Today 2025年

作者： Tingjia Zhang Chendi Yang Xiaowei Lv Tuoyu Zhao Wu Shi Wei Li Jia Liang Renchao Che School of Materials and Chemistry University of Shanghai for Science and Technology Shanghai 200093 China Laboratory of Advanced Materials Shanghai Key Lab of Molecular Catalysis and Innovative Materials Academy for Engineering and Technology Advanced Coatings Research Center of Ministry of Education of China Fudan University Shanghai 200438 China State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai 200433 China Zhangjiang Fudan International Innovation Center Fudan University Shanghai 201210 China Department of Physics Fudan University Shanghai 200433 China College of Smart Materials and Future Energy and State Key Laboratory of Photovoltaic Science and Technology Fudan University Shanghai 200433 China

Two-dimensional (2D) van der Waals (vdW) ferromagnets provide an excellent platform for exploring exotic physical phenomena such as magnetic skyrmions and quantum topological phases. However, the centrosymmetric crystal structure inherent in these 2D vdW ferromagnets theoretically precludes the formation of magnetic skyrmions and topological phases. In this study, we investigate the origin of the absence of magnetic skyrmions in 2D vdW ferromagnets and propose an effective strategy to induce lattice distortion through doping, thereby enabling the formation of magnetic skyrmions. Specifically, through the integration of density functional theory (DFT) calculations and multiple experimental characterizations, we demonstrate that Co doping in Fe 3 GeTe 2 induces substantial lattice distortion, resulting in a transformation from a centrosymmetric to a non-centrosymmetric crystal structure. This structural modification enables the emergence of a considerable Dzyaloshinskii-Moriya interaction (DMI), which is a necessary condition for skyrmion formation. While the DFT results do not directly predict specific spin textures, the presence of Néel-type skyrmions is verified through Lorentz transmission electron microscopy (LTEM). Additionally, the scalar spin chirality of these magnetic skyrmions acts as a virtual magnetic field, thereby inducing the topological Hall effect (THE) in Co-doped Fe 3 GeTe 2 . Our findings present a reliable method to manipulate spin textures and induce the THE in 2D vdW ferromagnets with non-zero DMI through lattice distortion, offering a promising route for the development of vdW ferromagnet-based spintronic devices.

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Observation of Dirac hierarchy in three-dimensional acoustic topological insulators

arXiv

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arXiv 2022年

作者： Yang, Linyun Wang, Yin Meng, Yan Zhu, Zhenxiao Xi, Xiang Yan, Bei Lin, Shuxin Chen, Jingming Shi, Bin-Jie Ge, Yong Yuan, Shou-Qi Sun, Hong-Xiang Liu, Gui-Geng Yang, Yihao Gao, Zhen Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China Research Center of Fluid Machinery Engineering and Technology Faculty of Science Jiangsu University Zhenjiang212013 China State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences Beijing100190 China Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University 21 Nanyang Link 637371 Singapore Interdisciplinary Center for Quantum Information State Key Lab. of Modern Optical Instrumentation College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China ZJU-Hangzhou Global Science and Technology Innovation Center Key Lab. of Advanced Micro Nano Electronic Devices & Smart Systems of Zhejiang ZJU-UIUC Institute Zhejiang University Hangzhou310027 China

Dirac cones (DCs) play a pivotal role in various unique phenomena ranging from massless electrons in graphene to robust surface states in topological insulators (TIs). Recent studies have theoretically revealed a full Dirac hierarchy comprising an eightfold bulk DC, a fourfold surface DC, and a twofold hinge DC, associated with a hierarchy of topological phases including first-order to third-order three-dimensional (3D) topological insulators, using the same 3D base lattice. Here, we report the first experimental observation of the Dirac hierarchy in 3D acoustic TIs. Using acoustic measurements, we unambiguously reveal that lifting of multifold DCs in each hierarchy can induce two-dimensional (2D) topological surface states with a fourfold DC in a first-order 3D TI, one-dimensional (1D) topological hinge states with a twofold DC in a second-order 3D TI, and zero-dimensional (0D) topological corner states in a third-order 3D TI. Our work not only expands the fundamental research scope of Dirac physics, but also opens up a new route for multidimensional robust wave manipulation. Copyright © 2022, The Authors. All rights reserved.

关键词： Electric insulators

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REDT: Remote exploitation detection technology for network infrastructure

引用

IOP Conference Series: Materials Science and engineering 2020年第1期715卷

作者： Xiaokang Yin Shengli Liu Fangfang Jia Da Xiao State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou CO 450000 China

An attacker exploits a remote vulnerability to execute arbitrary code on network infrastructure. It seriously threatens the security of network infrastructure. To detect the exploitation attack in a timely and effective way, in this paper, we present REDT, a remote exploitation detection technology based on the effect of exploitation attack. This method determines whether there is an authentication bypass exploitation by detecting the remote authentication process and saves attack traffic to the anomalous traffic database. With the database, we can replay the attack and analyze the exploitation. In the experiment, the detection accuracy rate reached 97.67%. In addition, this method does not rely on the signatures of the vulnerability and shellcode, so it can detect undisclosed vulnerabilities exploitation and provide abnormal traffic for the study of unknown vulnerabilities.

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