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Application of 3D U-Net Neural Networks in Extracting the Epoch of Reionization Signal from SKA-Low Observations Based on Real Observations of NCP Field from LOFAR

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arXiv 2024年

作者： Gao, Li-Yang Koopmans, Léon V.E. Mertens, Florent G. Munshi, Satyapan Li, Yichao Brackenhoff, Stefanie A. Ceccotti, Emilio Chege, J. Kariuki Acharya, Anshuman Ghara, Raghunath Giri, Sambit K. Iliev, Ilian T. Mellema, Garrelt Zhang, Xin Liaoning Key Laboratory of Cosmology and Astrophysics College of Sciences Northeastern University Shenyang110819 China Kapteyn Astronomical Institute University of Groningen P.O. Box 800 Groningen9700 AV Netherlands LERMA Observatoire de Paris Université PSL CNRS Sorbonne Université ParisF-75014 France INAF - Istituto di Radioastronomia Via P. Gobetti 101 Bologna40129 Italy Max-Planck-Institut für Astrophysik Garching85748 Germany Department of Physical Sciences Indian Institute of Science Education and Research Mohanpur WB Kolkata741246 India Van Swinderen Institute for Particle Physics and Gravity University of Groningen Nijenborgh 4 Groningen9747 AG Netherlands Department of Physics & Astronomy University of Sussex BrightonBN1 9QH United Kingdom Dept. of Astronomy & Oskar Klein Centre Stockholm University AlbaNova Stockholm University StockholmSE-106 91 Sweden MOE Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China

Neutral hydrogen (HI) serves as a crucial probe for the Cosmic Dawn and the Epoch of Reionization (EoR). Actual observations of the 21-cm signal often encounter challenges such as thermal noise and various systematic effects. To overcome these challenges, we simulate SKA-Low-depth images and process them with a deep learning method. We utilized foreground residuals acquired by LOFAR during actual North Celestial Pole (NCP) field observations, thermal and excess variances calculated via Gaussian process regression (GPR), and 21-cm signals generated with 21cmFAST for signal extraction tests. Our approach to overcome these foreground, thermal noise, and excess variance components employs a 3D U-Net neural network architecture for image analysis. When considering thermal noise corresponding to 1400 hours of integration, U-Net provides reliable 2D power spectrum predictions, and robustness tests ensure that we get realistic EoR signals. Adding foreground residuals, however, causes inconsistencies below the horizon delay-line. Lastly, evaluating both thermal and excess variance with observations up to 3700 and 14000 hours ensures reliable power spectrum estimations within the EoR window and across nearly all scales, respectively. Copyright © 2024, The Authors. All rights reserved.

关键词： Thermal noise

The gravitational-wave physics II: Progress

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arXiv 2021年

作者： Bian, Ligong Cai, Rong-Gen Cao, Shuo Cao, Zhoujian Gao, He Guo, Zong-Kuan Lee, Kejia Li, Di Liu, Jing Lu, Youjun Pi, Shi Wang, Jian-Min Wang, Shao-Jiang Wang, Yan Yang, Tao Yang, Xing-Yu Yu, Shenghua Zhang, Xin CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China Department of Astronomy Beijing Normal University Beijing100875 China National Astronomical Observatories Chinese Academy of Sciences 20A Datun Road Beijing100101 China Kavli Institute for Astronomy and Astrophysics Peking University Beijing100080 China School of Physical Sciences University of Chinese Academy of Sciences No.19A Yuquan Road Beijing100049 China School of Astronomy and Space Sciences University of Chinese Academy of Sciences 19A Yuquan Road Beijing100049 China Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences 19B Yuquan Road Beijing100049 China University of Chinese Academy of Sciences Hangzhou310024 China Department of Astronomy and School of Physics Huazhong University of Science and Technology Wuhan430074 China Asia Pacific Center for Theoretical Physics Pohang37673 Korea Republic of Department of Physics College of Sciences Northeastern University Shenyang110819 China MOE Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University Shenyang110819 China Department of Physics Chongqing University Chongqing401331 China

It has been a half-decade since the first direct detection of gravitational waves, which signifies the coming of the era of the gravitational-wave astronomy and gravitational-wave cosmology. The increasing number of the detected gravitational-wave events has revealed the promising capability of constraining various aspects of cosmology, astronomy, and gravity. Due to the limited space in this review article, we will briefly summarize the recent progress over the past five years, but with a special focus on some of our own work for the key Project "Physics associated with the gravitational waves" supported by the National Natural Science Foundation of China. In particular, (1) we have presented the mechanism of the gravitational-wave production during some physical processes of the early Universe, such as inflation, preheating and phase transition, and the cosmological implications of gravitational-wave measurements;(2) we have put constraints on the neutron star maximum mass according to GW170817 observations;(3) we have developed a numerical relativity algorithm based on the finite element method and a waveform model for the binary black hole coalescence along an eccentric orbit. Copyright © 2021, The Authors. All rights reserved.

关键词： Cosmology

Facilitating the Electrochemical Oxidation of ZnS through Iodide Catalysis for Aqueous Zinc-Sulfur Batteries

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Angewandte Chemie 2024年第9期136卷

作者： Peng Hei Ya Sai Chang Liu Wenjie Li Jing Wang Xiaoqi Sun Yu Song Xiao-Xia Liu Department of Chemistry Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China Key Laboratory of Data Analytics and Optimization for Smart Industry (Northeastern University) Ministry of Education 3-11 Wenhua Road Heping district Shenyang 110819 China

Aqueous zinc-sulfur (Zn-S) batteries show great potential for unlocking high energy and safety aqueous batteries. Yet, the sluggish kinetic and poor redox reversibility of the sulfur conversion reaction in aqueous solution challenge the development of Zn-S batteries. Here, we fabricate a high-performance Zn-S battery using highly water-soluble ZnI 2 as an effective catalyst. In situ experimental characterizations and theoretical calculations reveal that the strong interaction between I − and the ZnS nanoparticles (discharge product) leads to the atomic rearrangement of ZnS, weakening the Zn-S bonding, and thus facilitating the electrochemical oxidation reaction of ZnS to S. The aqueous Zn-S battery exhibited a high energy density of 742 Wh kg (sulfur) −1 at the power density of 210.8 W kg (sulfur) −1 and good cycling stability over 550 cycles. Our findings provide new insights about the iodide catalytic effect for cathode conversion reaction in Zn-S batteries, which is conducive to promoting the future development of high-performance aqueous batteries.

关键词： Aqueous Battery Catalytic Effect High Performance I− Additive Mechanism Study

Diatomic Catalysts for Aqueous Zinc-Iodine Batteries: Mechanistic Insights and Design Strategies

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Angewandte Chemie 2024年第49期136卷

作者： Peng Hei Ya Sai Wenjie Li Jianming Meng Yulai Lin Xiaoqi Sun Jing Wang Yu Song Xiao-Xia Liu Department of Chemistry Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University) Ministry of Education 3-11 Wenhua Road Heping district Shenyang 110819 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China

There has been a growing interest in developing catalysts to enable the reversible iodine conversion reaction for high-performance aqueous zinc-iodine batteries (AZIBs). While diatomic catalysts (DACs) have demonstrated superior performance in various catalytic reactions due to their ability to facilitate synergistic charge interactions, their application in AZIBs remains unexplored. Herein, we present, for the first time, a DAC comprising Mn−Zn dual atoms anchored on a nitrogen-doped carbon matrix (MnZn−NC) for iodine loading, resulting in a high-performance AZIB with a capacity of 224 mAh g −1 at 1 A g −1 and remarkable cycling stability over 320,000 cycles. The electron hopping along the Mn−N−Zn bridge is stimulated via a spin exchange mechanism. This process broadens the Mn 3d xy band width and enhances the metallic character of the catalyst, thus facilitating charge transfer between the catalysts and reaction intermediates. Additionally, the increased electron occupancy within the d-orbital of Zn elevates Zn's d-band center, thereby enhancing chemical interactions between MnZn−NC and I-based species. Furthermore, our mechanism demonstrates potential applicability to other Metal-Zn−NC DACs with spin-polarized atoms. Our work elucidates a clear mechanistic understanding of diatomic catalysts and provides new insights into catalyst design for AZIBs.

关键词： Aqueous zinc-iodine batteries Diatomic catalyst Catalytic mechanism Spin exchange

FAST drift scan survey for Hi intensity mapping: I. preliminary data analysis

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arXiv 2023年

作者： Li, Yichao Wang, Yougang Deng, Furen Yang, Wenxiu Hu, Wenkai Liu, Diyang Zhao, Xinyang Zuo, Shifan Shu, Shuanghao Li, Jixia Timbie, Peter Ansari, Réza Perdereau, Olivier Stebbins, Albert Wolz, Laura Wu, Fengquan Zhang, Xin Chen, Xuelei College of Sciences Northeastern University Shenyang110819 China National Astronomical Observatories Chinese Academy of Sciences Beijing100101 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences A20 Datun Road Chaoyang District Beijing100101 China Aix Marseille Univ CNRS CNES LAM Marseille France Australia Department of Physics University of Wisconsin – Madison MadisonWI53706 United States Université Paris-Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette91191 France Université Paris-Saclay CNRS IN2P3 IJCLab Orsay91405 France Fermi National Accelerator Laboratory P.O. Box 500 BataviaIL60510 United States Jodrell Bank Centre for Astrophysics Department of Physics & Astronomy The University of Manchester ManchesterM13 9PL United Kingdom National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University Shenyang110819 China Key Laboratory of Data Analytics and Optimization for Smart Industry Ministry of Education Northeastern University Shenyang110819 China

This work presents the initial results of the drift-scan observation for the neutral hydrogen (Hi) intensity mapping survey with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The data analyzed in this work were collected in night observations from 2019 through 2021. The primary findings are based on 28 hours of drift-scan observation carried out over seven nights in 2021, which covers 60 deg2 sky area. Our main findings are: (i) Our calibration strategy can successfully correct both the temporal and bandpass gain variation over the 4-hour drift-scan observation. (ii) The continuum maps of the surveyed region are made with frequency resolution of 28 kHz and pixel area of 2.95 arcmin2. The pixel noise levels of the continuum maps are slightly higher than the forecast assuming Tsys = 20 K, which are 36.0 mK (for 10.0 s integration time) at the 1050–1150 MHz band, and 25.9 mK (for 16.7 s integration time) at the 1323–1450 MHz band, respectively. (iii) The flux-weighted differential number count is consistent with the NRAO-VLA Sky Survey (NVSS) catalog down to the confusion limit ∼ 7 mJy/beam−1. (iv) The continuum flux measurements of the sources are consistent with that found in the literature. The difference in the flux measurement of 81 isolated NVSS sources is about 6.3%. Our research offers a systematic analysis for the FAST Hi intensity mapping drift-scan survey and serves as a helpful resource for further cosmology and associated galaxies sciences with the FAST drift-scan survey. Copyright © 2023, The Authors. All rights reserved.

关键词： data handling

Solid–Liquid Interfacial Coordination Chemistry Enables High-Capacity Ammonium Storage in Amorphous Manganese Phosphate

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Angewandte Chemie 2022年第37期134卷

作者： Duo Yang Prof. Yu Song Ming-Yue Zhang Zengming Qin Jie Liu Prof. Xiao-Xia Liu Department of Chemistry Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China School of Resources and Civil Engineering Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources Shenyang 110819 Liaoning China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern University 3-11 Wenhua Road Heping district Shenyang 110819 China Key Laboratory of Data Analytics and Optimization for Smart Industry Northeastern University) Ministry of Education China 3-11 Wenhua Road Heping district Shenyang 110819 China

Ammonium (NH 4 + ) ion as charge carrier is attracting attention in aqueous batteries. Yet, most NH 4 + host materials are still limited by the relatively low capacities. Here, we fabricated a manganese phosphate (MP-20) for NH 4 + ion storage. MP-20 displays a high capacity of 299.6 mAh g −1 at 1 A g −1 in ammonium acetate (NH 4 Ac) electrolyte, outperforming other reported NH 4 + host materials. Spectroscopy studies suggest a new NH 4 + /H + co-insertion mechanism. We surprisingly discover that the NH 4 Ac electrolyte plays an important role in improving the charge storage capability of the materials. Experimental and computational results indicate acetate ions can form coordination bonds with the Mn atoms, tailoring the electronic structure of the Mn atoms and the surrounding O atoms, and therefore facilitating the NH 4 + storage process. Our findings provide a new NH 4 + host material and propose the important role of the electrolyte-electrode coordination effect in aqueous ammonium batteries.

关键词： Aqueous Ammonium-Ion Batteries Charge Storage Mechanism Coordination Electrochemical Deposition Manganese Phosphate

The tianQin project: Current progress on science and technology

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arXiv 2020年

作者： Mei, Jianwei Bai, Yan-Zheng Bao, Jiahui Barausse, Enrico Cai, Lin Canuto, Enrico Cao, Bin Chen, Wei-Ming Chen, Yu Ding, Yan-Wei Duan, Hui-Zong Fan, Huimin Feng, Wen-Fan Fu, Honglin Gao, Qing Gao, TianQuan Gong, Yungui Gou, Xingyu Gu, Chao-Zheng Gu, De-Feng He, Zi-Qi Hendry, Martin Hong, Wei Hu, Xin-Chun Hu, Yi-Ming Hu, Yuexin Huang, Shun-Jia Huang, Xiang-Qing Jiang, Qinghua Jiang, Yuan-Ze Jiang, Yun Jiang, Zhen Jin, Hong-Ming Korol, Valeriya Li, Hong-Yin Li, Ming Li, Ming Li, Pengcheng Li, Rongwang Li, Yuqiang Li, Zhu Li, Zhulian Li, Zhu-Xi Liang, Yu-Rong Liang, Zheng-Cheng Liao, Fang-Jie Liu, Shuai Liu, Yan-Chong Liu, Li Liu, Pei-Bo Liu, Xuhui Liu, Yuan Lu, Xiong-Fei Lu, Yang Lu, Ze-Huang Luo, Yan Luo, Zhi-Cai Milyukov, Vadim Ming, Min Pi, Xiaoyu Qin, Chenggang Qu, Shao-Bo Sesana, Alberto Shao, Chenggang Shi, Changfu Su, Wei Tan, Ding-Yin Tan, Yujie Tan, Zhuangbin Tu, Liang-Cheng Wang, Bin Wang, Cheng-Rui Wang, Fengbin Wang, Guan-Fang Wang, Haitian Wang, Jian Wang, Lijiao Wang, Panpan Wang, Xudong Wang, Yan Wang, Yi-Fan Wei, Ran Wu, Shu-Chao Xiao, Chun-Yu Xu, Xiao-Shi Xue, Chao Yang, Fang-Chao Yang, Liang Yang, Ming-Lin Yang, Shan-Qing Ye, Bobing Yeh, Hsien-Chi Yu, Shenghua Zhai, Dongsheng Zhang, Caishi Zhang, Haitao Zhang, Jian-Dong Zhang, Jie Zhang, Lihua Zhang, Xin Zhang, Xuefeng Zhou, Hao Zhou, Ming-Yue Zhou, Ze-Bing Zhu, Dong-Dong Zi, Tie-Guang Luo, Jun Zhuhai519082 China Centre for Gravitational Experiments School of Physics MOE Key Laboratory of Fundamental Physical Quantities Measurement Hubei Key Laboratory of Gravitation and Quantum Physics PGMF Huazhong University of Science and Technology Wuhan430074 China DFH Satellite Co. Ltd. Beijing100094 China Yunnan Observatories Chinese Academy of Sciences Kunming650011 China Beijing Institute of Control Engineering Beijing100094 China Beijing Institute of Spacecraft System Engineering Beijing100094 China SISSA Via Bonomea 265 Trieste34136 Italy INFN Sezione di Trieste IFPU - Institute for Fundamental Physics of the Universe Via Beirut 2 Trieste34014 Italy Former Faculty Politecnico di Torino Corso Duca degli Abruzzi 24 Torino10129 Italy School of Physical Science and Technology Southwest University Chongqing400715 China SUPA School of Physics and Astronomy University of Glasgow GlasgowG12 8QQ United Kingdom National Astronomical Observatories Chinese Academy of Sciences Beijing100012 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing100049 China School of Physics and Astronomy University of Birmingham BirminghamB15 2TT United Kingdom Center for High Energy Physics Department of Physics State Key Laboratory of Nuclear Physics and Technology Peking University No.5 Yiheyuan Rd Beijing100871 China Lomonosov Moscow State University Sternberg Astronomical Institute Moscow119992 Russia Dipartimento di Fisica "G. Occhialini" Universitá degli Studi Milano Bicocca Piazza della Scienza 3 MilanoI-20126 Italy School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai200240 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing210023 China School of Astronomy and Space Science University of Science and Technology of China HefeiAnhui230026 China HannoverD-30167 Germany Leibniz Universität Hannover HannoverD-30167 Germany Department of Physics College of Sci

TianQin is a planned space-based gravitational wave (GW) observatory consisting of three earth orbiting satellites with an orbital radius of about 105 km. The satellites will form a equilateral triangle constellation the plane of which is nearly perpendicular to the ecliptic plane. TianQin aims to detect GWs between 10−4 Hz and 1 Hz that can be generated by a wide variety of important astrophysical and cosmological sources, including the inspiral of Galactic ultra-compact binaries, the inspiral of stellar-mass black hole binaries, extreme mass ratio inspirals, the merger of massive black hole binaries, and possibly the energetic processes in the very early universe or exotic sources such as cosmic strings. In order to start science operations around 2035, a roadmap called the 0123 plan is being used to bring the key technologies of TianQin to maturity, supported by the construction of a series of research facilities on the ground. Two major projects of the 0123 plan are being carried out. In this process, the team has created a new generation 17 cm single-body hollow corner-cube retro-reflector which has been launched with the QueQiao satellite on 21 May 2018;a new laser ranging station equipped with a 1.2 m telescope has been constructed and the station has successfully ranged to all the five retro-reflectors on the Moon;and the TianQin-1 experimental satellite has been launched on 20 December 2019 and the first round result shows that the satellite has exceeded all of its mission requirements. Copyright © 2020, The Authors. All rights reserved.

关键词： Orbits

Corrigendum to: The TianQin project: current progress on science and technology

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Progress of Theoretical and Experimental Physics 2021年第5期2021卷

作者： Mei, Jianwei Bai, Yan-Zheng Bao, Jiahui Barausse, Enrico Cai, Lin Canuto, Enrico Cao, Bin Chen, Wei-Ming Chen, Yu Ding, Yan-Wei Duan, Hui-Zong Fan, Huimin Feng, Wen-Fan Fu, Honglin Gao, Qing Gao, TianQuan Gong, Yungui Gou, Xingyu Gu, Chao-Zheng Gu, De-Feng He, Zi-Qi Hendry, Martin Hong, Wei Hu, Xin-Chun Hu, Yi-Ming Hu, Yuexin Huang, Shun-Jia Huang, Xiang-Qing Jiang, Qinghua Jiang, Yuan-Ze Jiang, Yun Jiang, Zhen Jin, Hong-Ming Korol, Valeriya Li, Hong-Yin Li, Ming Li, Pengcheng Li, Rongwang Li, Yuqiang Li, Zhu Li, Zhulian Li, Zhu-Xi Liang, Yu-Rong Liang, Zheng-Cheng Liao, Fang-Jie Liu, Qi Liu, Shuai Liu, Yan-Chong Liu, Li Liu, Pei-Bo Liu, Xuhui Liu, Yuan Lu, Xiong-Fei Lu, Yang Lu, Ze-Huang Luo, Yan Luo, Zhi-Cai Milyukov, Vadim Ming, Min Pi, Xiaoyu Qin, Chenggang Qu, Shao-Bo Sesana, Alberto Shao, Chenggang Shi, Changfu Su, Wei Tan, Ding-Yin Tan, Yujie Tan, Zhuangbin Tu, Liang-Cheng Wang, Bin Wang, Cheng-Rui Wang, Fengbin Wang, Guan-Fang Wang, Haitian Wang, Jian Wang, Lijiao Wang, Panpan Wang, Xudong Wang, Yan Wang, Yi-Fan Wei, Ran Wu, Shu-Chao Xiao, Chun-Yu Xu, Xiao-Shi Xue, Chao Yang, Fang-Chao Yang, Liang Yang, Ming-Lin Yang, Shan-Qing Ye, Bobing Yeh, Hsien-Chi Yu, Shenghua Zhai, Dongsheng Zhang, Caishi Zhang, Haitao Zhang, Jian-dong Zhang, Jie Zhang, Lihua Zhang, Xin Zhang, Xuefeng Zhou, Hao Zhou, Ming-Yue Zhou, Ze-Bing Zhu, Dong-Dong Zi, Tie-Guang Luo, Jun TianQin Research Center for Gravitational Physics & School of Physics and Astronomy Sun Yat-sen University (Zhuhai Campus) Zhuhai 519082 P.R. China Centre for Gravitational Experiments School of Physics MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics PGMF Huazhong University of Science and Technology Wuhan 430074 P.R. China SISSA Via Bonomea 265 34136 Trieste Italy and INFN Sezione di Trieste & IFPU – Institute for Fundamental Physics of the Universe Via Beirut 2 34014 Trieste Italy Former Faculty Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy Yunnan Observatories Chinese Academy of Sciences Kunming 650011 China School of Physical Science and Technology Southwest University Chongqing 400715 China Beijing Institute of Control Engineering Beijing 100094 P.R. China SUPA School of Physics and Astronomy University of Glasgow Glasgow G12 8QQ UK DFH Satellite Co. Ltd. Beijing 100094 P.R. China National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China School of Astronomy and Space Science University of Chinese Academy of Sciences Beijing 100049 China School of Physics and Astronomy University of Birmingham Birmingham B15 2TT United Kingdom Center for High Energy Physics & Department of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University No. 5 Yiheyuan Rd Beijing 100871 P.R. China Lomonosov Moscow State University Sternberg Astronomical Institute Moscow 119992 Russia Dipartimento di Fisica “G. Occhialini” Universitá degli Studi Milano Bicocca Piazza della Scienza 3 I-20126 Milano Italy School of Aeronautics and Astronautics Shanghai Jiao Tong University Shanghai 200240 China Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210023 & School of Astronomy and Space Science University of Science and Technology of China Hefei Anhui 230026 P.R. China Max-Planck-Institut für Gravitationsphysik (Al