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The FRB-searching Pipeline of the Tianlai Cylinder Pathfinder Array

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Research in Astronomy and Astrophysics 2024年第8期24卷 115-134页

作者： Zijie Yu Furen Deng Shijie Sun Chenhui Niu Jixia Li Fengquan Wu Wei-Yang Wang Yougang Wang Shifan Zuo Lin Shu Jie Hao Xiaohui Liu Reza Ansari Ue-Li Pen Albert Stebbins Peter Timbie Xuelei Chen National Astronomical Observatories Chinese Academy of Sciences University of Chinese Academy of Sciences Key Laboratory of Radio Astronomy and Technology Chinese Academy of Science institute of Astrophysics Central China Normal University institute of Automation Chinese Academy of Sciences Guangdong institute of Artificial Intelligence and Advanced Computing UniversitéParis—Saclay CNRS/IN2P3IJCLab institute of Astronomy and Astrophysics Academia Sinica Canadian institute for Theoretical Astrophysics University of Toronto60 Saint George Street Department of Physics University of Wisconsin—Madison Fermi National Accelerator Laboratory Department of Physics College of SciencesNortheastern University Center of High Energy Physics Peking University

This paper presents the design,calibration,and survey strategy of the Fast Radio Burst (FRB) digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder *** array,consisting of three parallel cylindrical reflectors and equipped with 96 dual-polarization feeds,is a radio interferometer array designed for conducting drift scans of the northern celestial *** FRB digital backend enables the formation of 96 digital beams,effectively covering an area of approximately 40 square degrees with the 3 dB *** pipeline demonstrates the capability to conduct an automatic search of FRBs,detecting at quasi-realtime and classifying FRB candidates *** current FRB searching pipeline has an overall recall rate of88%.During the commissioning phase,we successfully detected signals emitted by four well-known pulsars:PSR B0329+54,B2021+51,B0823+26,and B2020+*** report the first discovery of an FRB by our array,designated as FRB *** also investigate the optimal arrangement for the digitally formed beams to achieve maximum detection rate by numerical simulation.

关键词： (stars:) pulsars: general instrumentation: interferometers methods: data analysis telescopes

The siphonic energy transfer between hot solar wind and cold martian ionosphere through open magnetic flux rope

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Fundamental Research 2024年第4期4卷 882-889页

作者： Xiaojun Xu Lou-Chuang Lee Qi Xu Qing Chang Jing Wang Ming Wang Shaosui Xu Christian Mosti Charles J.Farrugia Xing Wang Yudong Ye Zilu Zhou Lei Luo Peishan He Shaoguan Cheng State Key Laboratory of Lunar and Planetary Sciences Macao University of Science and TechnologyMacao 999078China CNSA Macao Center for Space Exploration and Science Macao 999078China institute of Earth Science Academia SinicaTaipei 115029China institute of Space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518000China Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519000China Nanjing University of Information Science and Technology Nanjing 210000China Space ScienceLaboratory Universityof CaliforniaBerkeleyCA94320USA Space Research institute Austrian Academy of SciencesGraz 8010Austria University of New Hampshire NH 03824USA

A mech.nism for energy transfer from the solar wind to the Martian ionosphere through open magnetic flux rope is proposed based on the observations by Mars Atmosphere and Volatile EvolutioN(MAVEN).The satellite was located in the dayside magnetosheath at an altitude of about 70o km above the northern *** between the hot solar wind protons and the cold heavy ions/neutrals in the subsolar region can cool the protons and heat the heavy *** a result,the magnetosheath protons are siphoned into the ionosphere due to the thermal pressure gradient of protons and the heated heavy ions escape along the open magnetic field *** direct collisions in the lower-altitude region were not detected,this physical process is demonstrated by MAVEN measurements of enhanced proton density,decreased proton temperature and oppositely directed motions of hot and cool protons within the flux rope,which are very different from the observational features of the flux transfer events near the Earth's *** mech.nism could universally exist in many contexts where a collisionless plasma region is connected to a collisional plasma *** reconstructing the magnetic geometry and the cross-section of the flux rope using the Grad-Shafranov technique,the ion loss rates are quantitatively estimated to be on the order of 1023 s-l,which is much higher than previously estimated.

关键词： Mars Flux rope Solarwind Ionosphere Ion loss

Probing dark matter particles from evaporating primordial black holes via electron scattering in the CDEX-10 experiment

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Science China(Physics,mech.nics & Astronomy) 2024年

作者： Zhenhua Zhang Litao Yang Qian Yue Kejun Kang Yuanjing Li Haipeng An Greeshma C. Jianping Chang Yunhua Chen Jianping Cheng Wenhan Dai Zhi Deng Changhao Fang Xinping Geng Hui Gong Qiuju Guo Tao Guo Xuyuan Guo Li He Shengming He Jinwei Hu Hanxiong Huang Tuchen Huang Lin Jiang S.Karmakar Haubin Li Hanyu Li Jianmin Li Jin Li Qianyun Li Renmingjie Li Xueqian Li Yulan Li Yifan Liang Bin Liao FongKay Lin ShinTed Lin Jiaxuan Liu Shukui Liu Yandong Liu Yu Liu Yuanyuan Liu Hao Ma Yucai Mao Qiyuan Nie Jinhua Ning Hui Pan Ningchun Qi Jie Ren Xichao Ruan Monoj Kumar Singh Tianxi Sun Changjian Tang Yang Tian Guangfu Wang Junzheng Wang Li Wang Qing Wang Yufeng Wang Yunxiang Wang Henry Tsz-King Wong Shiyong Wu Yucheng Wu Haoyang Xing Rui Xu Yin Xu Tao Xue Yulu Yan Nan Yi Chunxu Yu Haijun Yu Jianfeng Yue Ming Zeng Zhi Zeng Bingtao Zhang Fengshou Zhang Lei Zhang Zhenyu Zhang Jizhong Zhao Kangkang Zhao Minggang Zhao Jifang Zhou Zuying Zhou Jingjun Zhu Sino-French institute of Nuclear and Technology Sun Yet-sen University School of Physics Nankai University Department of Physics Banaras Hindu University Department of Physics Beijing Normal University Key Laboratory of Particle and Radiation Imaging (Ministry of Education) and Department of Engineering Physics Tsinghua University Department of Physics Tsinghua University institute of Physics Academia Sinica Taipei NUCTECH Company YaLong River Hydropower Development Company College of Nuclear Science and Technology Beijing Normal University College of Physics Sichuan University School of Physics Peking University Department of Nuclear Physics China Institute of Atomic Energy

Dark matter （DM） is a major constituent of the ***,no definite evidence of DM particles （denoted as“χ”） has been found in DM direct detection （DD） experiments to *** is a novel concept of detectingχfrom evaporating primordial black holes （PBHs）.We search forχemitted from PBHs by investigating their interaction with target *** examined PBH masses range from 1×1015to 7×1016g under the current limits of PBH abundance *** 205.4 kg·day data obtained from the CDEX-10 experiment conducted in the China Jinping Underground Laboratory,we exclude theχ-electron （χ-e）elastic-scattering cross sectionσχe～5×10-29cm2forχwith a mass mχ0.1 ke V from our *** the higher radiation background but lower energy threshold （160 eV）,CDEX-10 fills a part of the gap in the previous *** (mχ,σχe) can be determined in the future,DD experiments are expected to impose strong constraints on fPBHfor large MPBHs.

关键词：

Bayesian-inspired minimum contamination designs under a double-pair conditional effect model

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Statistical Theory and Related Fields 2023年第4期7卷 336-349页

作者： Ming-Chung Chang institute of Statistical Science Academia SinicaTaipeiTaiwanChina

In two-level fractional factorial designs,conditional main effects can provide insights by which to analyze factorial effects and facilitate the de-aliasing of fully aliased two-factor ***-ditional main effects are of particular interest in situations where some factors are nested within *** of the relevant literature has focused on the development of data analysis tools that use conditional main effects,while the issue of optimal factorial design for a given linear model involving conditional main effects has been largely ***,Wu and Chang[*** 27(2017)997-1016]established a framework by which to optimize designs under a con-ditional effect *** theoretically sound,their results were limited to a single pair of conditional and conditioning *** this paper,we extend the applicability of their frame-work to double pairs of conditional and conditioning factors by providing the corresponding parameterization and effect *** propose a minimum contamination-based criterion by which to evaluate designs and develop a complementary set theory to facilitate the search of minimum contamination *** catalogues of 16-and 32-run minimum contamination designs are *** five to twelve factors,we show that all 16-run minimum contamination designs under the conditional effect model are also minimum aberration according to Fries and Hunter[Technometrics 22(1980)601-608].

关键词： Minimum aberration two-level factorials effect hierarchy functional prior

Theoretical Exploration of Alloying Effects on Stabilities and mech.nical Properties ofγʹPhase in Novel Co–Al–Nb-Base Superalloys

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Acta Metallurgica sinica(English Letters) 2024年第7期37卷 1238-1248页

作者： Guan-Cheng Gu Zhao-Jing Han Ze-Yu Chen Zhao-Xuan Li Sheng-Bao Xia Zheng-Ning Li Hua Jin Wei-Wei Xu Xing-Jun Liu Shenzhen Research institute of Xiamen University School of Aerospace EngineeringXiamen UniversityXiamen361005China institute of Materials Genome and Big Data Harbin Institute of TechnologyShenzhen518055China

The new developedγ/γʹCo–Al–Nb-base alloys show great potentials as high-temperature ***,finding appropriate compositions to improve performance of alloys still poses a great challenge to the development of Co–Al–Nb-base *** by the lack of alloying effects on fundamental properties of criticalγʹphase,we systematically performed a theoretical investigation on the effect of alloying elements TM(TM:Ti,V,Cr,Zr,Mo,Ta,W,Re,and Ru)on phase stabilities and mech.nical properties of L1_(2)-typeγʹ(Co,Ni)_(3)(Al,Nb).By analyzing the stability ofγʹphase with respect to its competitive B2 and D0_(19) phases,the results shown that Ti,V,and Cr enhance the L1_(2) stability and widen the L1_(2)–D0_(19) energy barrier,in which V yields the maximum *** analysis of electronic structure indicated that the alternation of valence electrons at fermi level would be the atomic origin for doping TM inγʹ*** calculated results of mech.nical properties shown that V and Cr are expected to be optimal dopant for enhancing the strength and the ductility ofγʹ*** addition of Ta is also beneficial for enhancing the strength at the slight expense of ductility ofγʹ*** drawing the mech.nical maps,the preferred composition range for the phases with desired properties is roughly demarcated in theory for the multi-addition of V/Cr and V/Ta inγʹ*** findings would be useful for optimizing the performance of novelγ/γʹCo–Al–Nb-base superalloys.

关键词： Co-Al-Nb-base superalloys γ/γʹdual-phase Phase stability mech.nical properties First-principle methods

Multi-UAVs Collaborative Path Planning in the Cramped Environment

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IEEE/CAA Journal of Automatica sinica 2024年第2期11卷 529-538页

作者： Siyuan Feng Linzhi Zeng Jining Liu Yi Yang Wenjie Song School of Automation Beijing Institute of TechnologyNanjing 210039China Nanjing Research institute of Electronics Technology Nanjing 210039China Yichang Testing Technique Research institute Yichang 443003China IEEE

Due to its flexibility and complementarity, the multiUAVs system is well adapted to complex and cramped workspaces, with great application potential in the search and rescue(SAR) and indoor goods delivery fields. However, safe and effective path planning of multiple unmanned aerial vehicles(UAVs)in the cramped environment is always challenging: conflicts with each other are frequent because of high-density flight paths, collision probability increases because of space constraints, and the search space increases significantly, including time scale, 3D scale and model scale. Thus, this paper proposes a hierarchical collaborative planning framework with a conflict avoidance module at the high level and a path generation module at the low level. The enhanced conflict-base search(ECBS) in our framework is improved to handle the conflicts in the global path planning and avoid the occurrence of local deadlock. And both the collision and kinematic models of UAVs are considered to improve path smoothness and flight safety. Moreover, we specifically designed and published the cramped environment test set containing various unique obstacles to evaluating our framework performance thoroughly. Experiments are carried out relying on Rviz, with multiple flight missions: random, opposite, and staggered, which showed that the proposed method can generate smooth cooperative paths without conflict for at least 60 UAVs in a few *** benchmark and source code are released in https://***/inin-xingtian/multi-UAVs-path-planner.

关键词： Collision avoidance conflict resolution multi-unmanned aerial vehicles(UAVs)system path planning

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Underwater Directional Acoustic Source Based on Pentamode Material

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Acta mech.nica Solida sinica 2024年第1期37卷 1-9页

作者： Binghao Zhao Peng Wang Dongwei Wang Gengkai Hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal *** these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other ***,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted *** contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency

INSTABILITY OF HAGEN-POISEUILLE FLOW FOR NON-AXISYMMETRIC MODE

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Applied Mathematics and mech.nics(English Edition) 1989年第5期10卷 407-417页

作者：王发民 J. T. Stuart (F. R. S.) institute of mech. academia sinica Beijing Imperial College U. K.

An investigation is described for instability problem of flow through a pipe of circular cross section. As a disturbance motion, we consider a general non-axisym-metric mode. An associated amplitude or modulation equation has been derived for this disturbance motion. This equation belongs to a diffusion *** coefficient of it can be negative while Reynolds number increases, because of the complex interaction between molecular diffusion and convection. The negative diffusivity, when it occurs, causes a concentration and focussing of energy within decaying slugs, acting as a role of reversing natural decays.

关键词： INSTABILITY OF HAGEN-POISEUILLE FLOW FOR NON-AXISYMMETRIC MODE

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Quantitative Applications of Weather Satellite Data for Nowcasting:Progress and Challenges

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Journal of Meteorological Research 2024年第3期38卷 399-413页

作者： Jun LI Jing ZHENG Bo LI Min MIN Yanan LIU Chian-Yi LIU Zhenglong LI WPaul MENZEL Timothy J.SCHMIT John L.CINTINEO Scott LINDSTROM Scott BACHMEIER Yunheng XUE Yayu MA Di DI Han LIN Innovation Centre for Fengyun Meteorological Satellite(FYSIC) National Satellite Meteorological CentreChina Meteorological AdministrationBeijing100081China School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen University and Southern Laboratory of Ocean Science and EngineeringZhuhai519082China Key Laboratory of Geographic Information Science(Ministry of Education) East China Normal UniversityShanghai200241China Research Center for Environmental Changes Academia SinicaTaipei11529China Cooperative institute for Meteorological Satellite Studies University of Wisconsin-MadisonMadisonWI53706USA Sensors and Calibration Branch STAR/NESDISMadisonWI53706USA Wuxi University Wuxi214105China School of Computer Science Chengdu University of Information TechnologyChengdu610225China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing210044China Key Laboratory of Spatial Data Mining and Information Sharing of Ministry of Education National and Local Joint Engineering Research Center of Satellite Geospatial Information TechnologyFuzhou UniversityFuzhou350108China

Monitoring and predicting highly localized weather events over a very short-term period,typically ranging from minutes to a few hours,are very important for decision makers and public *** these events usually relies on radar observations through monitoring and *** advanced high-resolution imaging and sounding observations from weather satellites,nowcasting can be enhanced by combining radar,satellite,and other data,while quantitative applications of those data for nowcasting are advanced through using machine learning *** applications include monitoring the location,impact area,intensity,water vapor,atmospheric instability,precipitation,physical properties,and optical properties of the severe storm at different stages(pre-convection,initiation,development,and decaying),identification of storm types(wind,snow,hail,etc.),and predicting the occurrence and evolution of the *** observations can provide information on the environmental characteristics in the preconvection stage and are very useful for situational awareness and storm *** paper provides an overview of recent progress on quantitative applications of satellite data in nowcasting and its challenges,and future perspectives are also addressed and discussed.

关键词： weather satellite quantitative applications nowcasting pre-convection

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