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Evidence for particle acceleration approaching PeV energies in the w51 complex

Science Bulletin 2024年第18期69卷 2833-2841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, Zhe Chang, J. Chang, J.F. Chen, A.M. Chen, E.S. Chen, H.X. Chen, liang Chen, lin Chen, long 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. 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. 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. Hasan, M. He, H.H. He, H.N. He, J.Y. He, Y. 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. Ji, X.l. Jia, H.Y. Jia, K. Jiang, K. Jiang, X.w. Jiang, Z.J. Jin, M. Kang, M.M. Karpikov, I. Kuleshov, D. Kurinov, K. li, B.B. li, C.M. li, Cheng li, Cong li, D. li, F. li, H.B. li, H.C. li, Jian li, Jie li, K. li, S.D. 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, 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. 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. Key laboratory of Particle Astrophysics & Experimental Physics Division & Computing Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China University of Chinese Academy of Sciences Beijing 100049 China TIANFU Cosmic Ray Research Center Chengdu China Dublin Institute for Advanced Studies 31 Fitzwilliam Place 2 Dublin Ireland Max-Planck-Institut for Nuclear Physics P.O. Box 103980 Heidelberg 69029 Germany School of Physical Science and Technology & School of Information Science and Technology Southwest Jiaotong University Chengdu 610031 China School of Astronomy and Space Science Nanjing University Nanjing 210023 China Center for Astrophysics Guangzhou University Guangzhou 510006 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 China University of Science and Technology of China Hefei 230026 China State Key laboratory of Particle Detection and Electronics China Key laboratory of Dark Matter and Space Astronomy & Key laboratory of Radio Astronomy Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210023 China Research Center for Astronomical Computing Zhejiang Laboratory Hangzhou 311121 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 China Key laboratory of Cosmic Rays (Tibet University) Ministry of Education Lhasa 850000 China National Astronomical Observatories Chinese Academy of Sciences Beijing 100101 China School of Physics and Astronomy (Zhuhai) & School of Physics (Guangzhou) & Sino-French Institute of Nuclear Engineering and Technology (Zhuhai) Sun Yat-sen University Zhuhai 519000 & Guangzhou 510275 Guangdong China Institute of Frontier and

The γ-ray emission from the w51 complex is widely acknowledged to be attributed to the interaction between the cosmic rays (CRs) accelerated by the shock of supernova remnant (SNR) w51C and the dense molecular clouds in the adjacent star-forming region, w51B. However, the maximum acceleration capability of w51C for CRs remains elusive. Based on observations conducted with the large High Altitude Air Shower Observatory (lHAASO), we report a significant detection of γ rays emanating from the w51 complex, with energies from 2 to 200 TeV. The lHAASO measurements, for the first time, extend the γ-ray emission from the w51 complex beyond 100 TeV and reveal a significant spectrum bending at tens of TeV. By combining the "π0-decay bump" featured data from Fermi-lAT, the broadband γ-ray spectrum of the w51 region can be w.l.-characterized by a simple pp-collision model. The observed spectral bending feature suggests an exponential cutoff at ∼400 TeV or a power-law break at ∼200 TeV in the CR proton spectrum, most likely providing the first evidence of SNRs serving as CR accelerators approaching the PeV regime. Additionally, two young star clusters within w51B could also be theoretically viable to produce the most energetic γ rays observed by lHAASO. Our findings strongly support the presence of extreme CR accelerators within the w51 complex and provide new insights into the origin of Galactic CRs. © 2024 Science China Press

关键词： Cosmic rays

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Nonreciprocal generation of Schrodinger cat state induced by topology

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Science China(Physics,Mechanics & Astronomy) 2024年第4期67卷 23-30页

作者： Zi-Hao li li-li Zheng Ying wu Xin-You lü School of Physics and Institute for Quantum Science and Engineering Huazhong University of Science and Technologyand Wuhan Institute of Quantum TechnologyWuhan 430074China Key laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education Jianghan UniversityWuhan 430074China

The Schrodinger cat state produced differently in two directions is anticipated to be a critical quantum resource in quantum information *** exploring the interplay between quantum nonreciprocity and topology in a one-dimensional microcavity array,we obtain the Schrodinger cat state(a pure quantum state)in a chosen direction at the edge cavity,whereas a classical state in the other *** nonreciprocal generation of the cat state originates from the topologically protected chiralitymode excitation in the nontrivial phase,but in the trivial phase,the nonreciprocal generation of cat state ***,our proposal is switchable by tuning the parameters so that a topological phase transition ***,the obtained cat state has nonreciprocal high fidelity,nonclassicality,and quantum coherence,which are sufficient to be used in various one-way quantum technologies,e.g.,invisible quantum sensing,noise-tolerant quantum computing,and chiral quantum *** work provides a general approach to control quantum nonreciprocities with the topological effect,which substantially broadens the fields of nonreciprocal photonics and topological physics.

关键词： Schr?dinger cat state nonreciprocity topology

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Approximate contact solutions for non-axisymmetric homogeneous and power-law graded elastic bodies:A practical tool for design engineers and tribologists

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Friction 2024年第2期12卷 340-355页

作者： Valentin l.POPOV Qiang li Emanuel w.l.ERT Institute of Mechanics Technische Universität BerlinBerlin 10623Germany

In two recent papers,approximate solutions for compact non-axisymmetric contact problems of homogeneous and power-law graded elastic bodies have been suggested,which provide explicit analytical relations for the force–approach relation,the size and the shape of the contact area,as w.l. as for the pressure distribution *** solutions were derived for profiles,which only slightly deviate from the axisymmetric *** the present paper,they undergo an extensive testing and validation by comparison of solutions with a great variety of profile shapes with numerical solutions obtained by the fast Fourier transform(FFT)-assisted boundary element method(BEM).Examples are given with quite significant deviations from axial symmetry and show surprisingly good agreement with numerical solutions.

关键词： normal contact non-axisymmetric indenter extremal principle generalized method of dimensionality reduction(MDR) functional elastic grading

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Dynamic Event-Triggered Consensus Control for Input Constrained Multi-Agent Systems with a Designable Minimum Inter-Event Time

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 649-660页

作者： Meilin li Yue long Tieshan li Hongjing liang C.l.Philip Chen the School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu 611731China IEEE the Yangtze Delta Region Institute University of Electronic Science and Technology of ChinaHuzhou 313000 the laboratory of Electromagnetic Space Cognition and Intelligent Control Beijing 100089China the School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006

This paper investigates the consensus control of multi-agent systems(MASs) with constrained input using the dynamic event-triggered mechanism(ETM).Consider the MASs with small-scale networks where a centralized dynamic ETM with global information of the MASs is first ***,a distributed dynamic ETM which only uses local information is developed for the MASs with large-scale *** is shown that the semi-global consensus of the MASs can be achieved by the designed bounded control protocol where the Zeno phenomenon is eliminated by a designable minimum inter-event *** addition,it is easier to find a trade-off between the convergence rate and the minimum inter-event time by an adjustable ***,the results are extended to regional consensus of the MASs with the bounded control *** simulations show the effectiveness of the proposed approach.

关键词： Constrained input designable minimum inter-event time directed communication topology dynamic event-triggered mechanism MASs consensus control

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Stability and performance analysis of the compressed Kalman filter algorithm for sparse stochastic systems

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Science China(Technological Sciences) 2024年第2期67卷 380-394页

作者： li RongJiang GAN Die XIE SiYu lüJinHu Key laboratory of Systems and Control Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100049China Zhongguancun laboratory Beijing 100049China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

This paper considers the problem of estimating unknown sparse time-varying signals for stochastic dynamic *** deal with the challenges of extensive sparsity,we resort to the compressed sensing method and propose a compressed Kalman filter(KF)*** algorithm first compresses the original high-dimensional sparse regression vector via the sensing matrix and then obtains a KF estimate in the compressed low-dimensional ***,the original high-dimensional sparse signals can be w.l. recovered by a reconstruction *** ensure stability and establish upper bounds on the estimation errors,we introduce a compressed excitation condition without imposing independence or stationarity on the system signal,and therefore suitable for feedback *** further present the performance of the compressed KF ***,we show that the mean square compressed tracking error matrix can be approximately calculated by a linear deterministic difference matrix equation,which can be readily evaluated,analyzed,and ***,a numerical example demonstrates that our algorithm outperforms the standard uncompressed KF algorithm and other compressed algorithms for estimating high-dimensional sparse signals.

关键词： sparse signal compressed sensing Kalman filter algorithm compressed excitation condition stochastic stability tracking performance

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HwD-YOlO: A New Vision-Based Helmet wearing Detection Method

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Computers, Materials and Continua 2024年第3期80卷 4543-4560页

作者： Sun l. li H. wang l. College of Information Science and Technology Beijing University of Technology Beijing 100124 China Chinese Institute of Coal Science Beijing 100013 China State Key laboratory for Intelligent Coal Mining and Strata Control Beijing 100013 China Engineering Research Center of Digital Community of Ministry of Education Beijing 100124 China

It is crucial to ensure workers wear safety helmets when working at a workplace with a high risk of safety accidents, such as construction sites and mine tunnels. Although existing methods can achieve helmet detection in images, their accuracy and speed still need improvements since complex, cluttered, and large-scale scenes of real workplaces cause server occlusion, illumination change, scale variation, and perspective distortion. So, a new safety helmet-wearing detection method based on deep learning is proposed. Firstly, a new multi-scale contextual aggregation module is proposed to aggregate multi-scale feature information globally and highlight the details of concerned objects in the backbone part of the deep neural network. Secondly, a new detection block combining the dilate convolution and attention mechanism is proposed and introduced into the prediction part. This block can effectively extract deep features while retaining information on fine-grained details, such as edges and small objects. Moreover, some newly emerged modules are incorporated into the proposed network to improve safety helmet-wearing detection performance further. Extensive experiments on open dataset validate the proposed method. It reaches better performance on helmet-wearing detection and even outperforms the state-of-the-art method. To be more specific, the mAP increases by 3.4%, and the speed increases from 17 to 33 fps in comparison with the baseline, You Only look Once (YOlO) version 5X, and the mean average precision increases by 1.0% and the speed increases by 7 fps in comparison with the YOlO version 7. The generalization ability and portability experiment results show that the proposed improvements could serve as a springboard for deep neural network design to improve object detection performance in complex scenarios. Copyright © 2024 The Authors. Published by Tech Science Press.

关键词： attention mechanism deep learning feature extraction Object detection safety helmet wearing detection

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Novel medium entropy perovskite oxide Sr(FeCoNiMo)_(1/4)O_(3−δ)for zinc-air battery cathode

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Journal of Energy Chemistry 2024年第9期96卷 669-678页

作者： Kaixin li Juntao Gao Xu Han Qi Shao Zhe lü School of Physics Harbin Institute of TechnologyHarbin 150001HeilongjiangChina Heilongjiang Provincial Key laboratory of Advanced Quantum Functional Materials and Sensor Components Harbin 150001HeilongjiangChina

It is widely recognized that the development of ZABs is impeded by the kinetic bottleneck of oxygen evolution reaction(OER)and oxygen reduction reaction(ORR).The application of conformational entropy strategy to oxides often involves introducing multiple elements with different properties,thereby providing outstanding bifunctional catalytic activity for OER/***,the possible underlying catalytic pathways and potential interactions between various components are still poorly *** paper presents an excellent medium-entropy perovskite oxide,Sr(FeCoNiMo)_(1/4)O_(3−δ)(lower overpotential of 301 mV at 10 mA cm^(−2)).Zinc-air batteries employing it as a cathode catalyst demonstrate excellent round-trip efficiency(62%).By combining theoretical calculation with experiments,we aim to establish the link between the electronic structure of perovskite oxides with different elemental compositions and their OER *** reveals that the conformational entropy strategy can simultaneously shift the O 2p-band center and metal d-band center of perovskite oxide towards the vicinity of the Fermi energy level,thereby triggering a more favorable lattice oxygen-participated mechanism(lOM)during the OER *** outcomes of this work provide crucial insights into the role of conformational entropy strategies in oxygen catalysis and offer potential avenues for constructing efficient and stable electrocatalysts.

关键词： Sr(FeCoNiMo)_(1/4)O_(3−δ) Bifunctional catalyst Medium entropy lOM Rechargeable zinc-air batteries

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Error-based adaptive optimal tracking control of nonlinear discrete-time systems

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Science China(Information Sciences) 2024年第1期67卷 154-167页

作者： Chun li Jinliang DING Frank l.lEwIS Tianyou CHAI State Key laboratory of Synthetical Automation for Process Industries Northeastern University UTA Research Institute The University of Texas at Arlington

In this paper,for the output tracking problem of nonlinear discrete-time systems,a performance index is newly defined using the adaptive dynamic programming(ADP) technique to completely eliminate tracking errors in *** contrast to traditional definitions of performance indices in other ADP-based methods,the proposed performance index is not only designed from the perspective of output tracking errors but also introduced errors of system states and control inputs at adjacent stages,which is suitable for practical situations in many industrial applications,such as the alumina production,the flotation process,and the mineral grinding *** proved that the obtained controller can make the system output fully track the given reference trajectory by applying the iterative criteria of the ADP *** addition,the proposed algorithm was implemented using a data-driven technique and neural networks to avoid analyzing and deducing the complicated dynamics of actual industrial ***,using historical data for a forced-circulation evaporation system in the alumina production process,the effect of the proposed approach was verified through a numerical simulation and compared with that of the proportional-integral controller.

关键词： adaptive dynamic programming iterative criteria performance index tracking errors tracking problem

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Enhancing force sensing in a squeezed optomechanical system with quantum nondemolition measurement

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Communications in Theoretical Physics 2024年第1期76卷 49-60页

作者： Shi-lei Chao Zi-Hao li Xin-You lü School of Physics Huazhong University of Science and Technology430074 WuhanChina

A theoretical scheme is proposed to enhance the sensitivity of force sensors with quantum nondemolition measurement(QND)in an optomechanical setup assisted by four-tone optical driving and an optical parametric amplifier(OPA).with the help of special drive,the system can be simplified as the typical type of QND for force sensing,so that the backaction noise can be evaded to surpass the standard quantum ***,the added noise can be suppressed owing to the modified optical susceptibility resulting from the *** introducing two oscillators coupling with two charged bodies respectively,the signal can be enhanced with the nonlinearity caused by Coulomb interaction,while the noise presents an exponential ***,considering the homodyne detection effect,the range of system parameters and frequency bands w.l. be *** present investigation may provide a route toward simultaneously evading backaction noise,reducing the mechanical thermal noise,and enhancing the external signal,which can be an alternative design for sensitive devices.

关键词： force sensing optical parametric amplifier quantum non-demolition measurement optomechanical system

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Complex-frequency waves:beat loss and win sensitivity

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing Cheng Tao l School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical Medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National laboratory of Solid State Microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

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