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Multiwavelength study of low-luminosity 6.7-GHz methanol masers

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Research in Astronomy and Astrophysics 2011年第2期11卷 137-155页

作者： Yuan-wei Wu,Ye xu and Ji Yang purple mountain observatory,chinese academy of sciences,nanjing 210008,china purple mountain observatory Chinese Academy of Sciences

We present results of 13CO（1-0）,C18O（1-0）,and HCO＋（1-0） map observations and N2H＋（1-0） single point observations directed towards a sample of nine low-luminosity 6.7-GHz masers.N2H ＋ line emission has been detected from six out of nine sources,C18O line emission has been detected from eight out of nine sources,and HCO ＋ and 13CO emission has been detected in all *** particular,a ＂blue profile＂ of the HCO ＋ spectrum,a signature of inflow,is found towards one *** integrated intensity emission maps,we identified 17 cores in the *** them,nine cores are closely associated with low-luminosity methanol *** these cores,we derive the column densities,core sizes,masses and molecular *** of our results with similar molecular line surveys towards the southern sky methanol masers indicates that linewidths of our sample,including only the low-luminosity masers,are smaller than the sample that includes both lowand high-luminosity *** the maser associated cores,their gas masses have the same order of magnitude as their virial masses,indicating that these cores are gravitationally bound *** addition,we have found from our observations that the low-luminosity methanol masers tend to coexist with H2O masers and outflows rather than with OH masers.

关键词： masers -- ISM: abundances -- ISM: molecules -- stars: formation

Primary scientific results of Chang'E-1 lunar mission

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Science china Earth sciences 2010年第11期53卷 1565-1581页

作者： OUYANG ZiYuan1,2, LI ChunLai1, ZOU YongLiao1, ZHANG HongBo1, Lü Chang1, LIU JianZhong1, LIU JianJun1, ZUO wei1, SU Yan1, WEN weiBin1, BIAN wei1, ZHAO BaoChang3, WANG JianYu4, YANG JianFeng3, CHANG Jin5, WANG HuanYu6, ZHANG XiaoHui7, WANG ShiJin7, WANG Min1, REN Xin1, MU LingLi1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG Liang1, ZHANG zhouBin1, ZHENG Lei1, ZHU XinYing1, ZHENG YongChun1, LI JunDuo1, ZOU XiaoDuan1, xu Chun1, SHI ShuoBiao1, GAO YiFei1 & GAO GuanNan1 1 National Astronomical Observatories, chinese academy of sciences, Beijing 100012, china 2 Institute of Geochemistry, chinese academy of sciences, Guiyang 550002, china 3 Xi’an Institute of Optics and Precision Mechanics, chinese academy of sciences, Xi’an 710119, china 4 Shanghai Institute of Technical Physics, chinese academy of sciences, Shanghai 200083, china 5 purple mountain observatory, chinese academy of sciences, nanjing 210008, china 6 Institute of High Energy Physics, chinese academy of sciences, Beijing 100049, china 7 Center for Space Science and Applied Research, chinese academy of sciences, Beijing 100190, china National Astronomical Observatories Chinese Academy of Sciences Beijing China Institute of Geochemistry Chinese Academy of Sciences Guiyang China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an China Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai China purple mountain observatory Chinese Academy of Sciences Nanjing China Institute of High Energy Physics Chinese Academy of Sciences Beijing China Center for Space Science and Applied Research Chinese Academy of Sciences Beijing China

The strategic plan for the development of the unmanned chinese Lunar Exploration Program is characterized by three distinct stages: "orbiting around", "landing on" and "returning from" the Moon. The first chinese lunar probe, Chang'E-1, which was successfully launched on October 24th, 2007 at Xichang Satellite Launch Center, and guided to crash on the Moon on March 1st, 2009, at 52.36°E, 1.50°S, in the north of Mare Fecunditatis, is the first step towards the "orbiting around" stage. The Chang'E-1 mission lasted 495 days, exceeding the expected life-span by about four months. A total of 1.37 TB raw data was received from Chang'E-1. It was then processed into 4 TB scientific data products at various levels. Many scientific results have been obtained by analyzing these data, including especially the "global lunar image from the first chinese lunar explora- tion mission". All scientific goals of Chang'E-1 have been achieved. It provides much useful materials for further advances of lunar sciences and planetary chemistry. Meanwhile, these results will serve as a firm basis for future chinese lunar missions.

关键词： lunar orbiter Chang’E-1 scientific data results

Simulation study of the performance of the Very Large Area gamma-ray Space Telescope

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Nuclear Science and Techniques 2024年第9期35卷 1-17页

作者： xu Pan wei Jiang Chuan Yue Shi-Jun Lei Yu-Xin Cui Qiang Yuan Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China

The Very Large Area gamma-ray Space Telescope(VLAST)is a mission concept proposed to detect gamma-ray photons through both Compton scattering and electron–positron pair production mechanisms,thus enabling the detection of photons with energies ranging from MeV to *** project aims to conduct a comprehensive survey of the gamma-ray sky from a low-Earth orbit using an anti-coincidence detector,a tracker detector that also serves as a low-energy calorimeter,and a high-energy imaging *** developed a Monte Carlo simulation application of the detector using the GEANT4 toolkit to evaluate the instrument performance,including the effective area,angular resolution,and energy resolution,and explored specific optimizations of the detector *** simulation-based analysis indicates that the current design of the VLAST is physically feasible,with an acceptance above 10 m^(2)sr which is four times larger than that of the Fermi-LAT,an energy resolution better than 2%at 10 GeV,and an angular resolution better than 0.2◦at 10 *** VLAST project promises to make significant contributions to the field of gamma-ray astronomy and enhance our understanding of the cosmos.

关键词： Space astronomy Gamma-ray telescope Calorimeter Monte Carlo simulation

Empowering over-the-air personalized federated learning via RIS

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Science china(Information sciences) 2024年

作者： wei SHI Jiacheng YAO Jindan xu wei xu Lexi xu Chunming ZHAO National Mobile Communications Research Laboratory Southeast University purple mountain Laboratories School of Electrical and Electronics Engineering Nanyang Technological University Research Institute China United Network Communications Corporation

Federated learning (FL) is a promising distributed learning approach due to its privacy-enhancing characteristic [1–3].To enhance communication efficiency of FL, over-the-air computation (AirComp) has emerged as a key technique by exploiting the waveform superposition property of multiple access channels [4, 5]. Although AirComp-enabled FL(AirFL) offers significant performance gains, it does not address the data heterogeneity in most real-life FL scenarios with non-independent and identically distributed local datasets. Such data heterogeneity hinders the generalization of a single global consensus model. To this end, preliminary works have been made to develop a personalized AirFL framework via clustering algorithms, where different models are trained for different clusters under the orchestration of the parameter server (PS)[6, 7]. However, this personalized framework requires large-scale antennas to combat interference, leading to a significant escalation in hardware cost.

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RIS-Assisted Cell-Free MIMO: A Survey

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ZTE Communications 2024年第1期22卷 77-86页

作者： ZHAO Yaqiong KE Hongqin xu wei YE Xinquan CHEN Yijian National Mobile Communications Research Laboratory Southeast UniversityNanjing 211189China purple mountain Laboratories Nanjing 211111China ZTE Corporation Shenzhen 518507China

Cell-free(CF)multiple-input multiple-output(MIMO)is a promising technique to enable the vision of ubiquitous wireless connectivity for next-generation network *** to traditional co-located massive MIMO,CF MIMO allows geographically distributed access points(APs)to serve all users on the same time-frequency resource with spatial multiplexing techniques,resulting in better performance in terms of both spectral efficiency and coverage ***,the performance gain is achieved at the expense of deploying more APs with high cost and power *** address this issue,the recently proposed reconfigurable intelligent surface(RIS)technique stands out with its unique advantages of low cost,low energy consumption and *** this paper,we provide an overview of RIS-assisted CF MIMO and its interaction with advanced optimization designs and novel ***,recent studies on typical performance metrics such as energy efficiency(EE)and spectral efficiency(SE)are ***,the application of RIS-assisted CF MIMO techniques in various future communication systems is also ***,we briefly discuss the technical challenges and open problems for this area to inspire research direction and fully exploit its potential in meeting the demands of future wireless communication systems.

关键词： mmWave beyond 5G(B5G) Internet of Everything(IoE) cell-free MIMO RIS unmanned aerial vehicle(UAV) physical layer security(PLS) wireless energy transfer(WET)

RIS-Assisted Cell-Free MIMO:A Survey

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ZTE Communications 2024年 77-86页

作者： ZHAO Yaqiong KE Hongqin xu wei YE Xinquan CHEN Yijian purple mountain Laboratories National Mobile Communications Research Laboratory Southeast University ZTE Corporation

Cell-free(CF) multiple-input multiple-output(MIMO) is a promising technique to enable the vision of ubiquitous wireless connectivity for next-generation network *** to traditional co-located massive MIMO,CF MIMO allows geographically distributed access points(APs) to serve all users on the same time-frequency resource with spatial multiplexing techniques,resulting in better performance in terms of both spectral efficiency and coverage ***,the performance gain is achieved at the expense of deploying more APs with high cost and power *** address this issue,the recently proposed reconfigurable intelligent surface(RIS)technique stands out with its unique advantages of low cost,low energy consumption and *** this paper,we provide an overview of RIS-assisted CF MIMO and its interaction with advanced optimization designs and novel ***,recent studies on typical performance metrics such as energy efficiency(EE) and spectral efficiency(SE) are ***,the application of RIS-assisted CF MIMO techniques in various future communication systems is also ***,we briefly discuss the technical challenges and open problems for this area to inspire research direction and fully exploit its potential in meeting the demands of future wireless communication systems.

关键词：

面向智能无人通信系统的因果性对抗攻击生成算法

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通信学报 2024年第1期45卷 54-62页

作者：禹树文许威姚嘉铖东南大学移动通信全国重点实验室江苏南京210096 网络通信与安全紫金山实验室江苏南京211111

考虑到基于梯度的对抗攻击生成算法在实际通信系统部署中面临着因果性问题,提出了一种因果性对抗攻击生成算法。利用长短期记忆网络的序列输入输出特征与时序记忆能力,在满足实际应用中存在的因果性约束前提下,有效提取通信信号的时序... 详细信息

考虑到基于梯度的对抗攻击生成算法在实际通信系统部署中面临着因果性问题,提出了一种因果性对抗攻击生成算法。利用长短期记忆网络的序列输入输出特征与时序记忆能力,在满足实际应用中存在的因果性约束前提下,有效提取通信信号的时序相关性,增强针对无人通信系统的对抗攻击性能。仿真结果表明,所提算法在同等条件下的攻击性能优于泛用对抗扰动等现有的因果性对抗攻击生成算法。

关键词：智能通信系统对抗攻击深度学习因果系统长短期记忆网络

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一种新型射电天文频谱仪——声表面波频谱仪

天体物理学报 1993年第1期13卷 85-91页

作者：陈东培宫俊杰周献文解述魏玉兰徐之材周体健中国科学院声学研究所北京100080 中国科学院紫金山天文台北京大学地球物理系

本文简要介绍一种以傅里叶交换的线性调频Z变换(CZT)算法为工作原理,以声表面波(SAW)器件为支持性技术的新型射电频谱仪.给出它在紫金山天文台青海站13.7m射电天文望远镜13mm接收系统上对22GHz水分子脉泽源试观测的结果,实践表明它具有... 详细信息

本文简要介绍一种以傅里叶交换的线性调频Z变换(CZT)算法为工作原理,以声表面波(SAW)器件为支持性技术的新型射电频谱仪.给出它在紫金山天文台青海站13.7m射电天文望远镜13mm接收系统上对22GHz水分子脉泽源试观测的结果,实践表明它具有宽带、高频率分辨率、全固化、机械稳定性好、对工作环境要求不高、可靠性高等优点.在射电天文星际分子谱线观测技术中有一定实用价值.

关键词：仪器设备射电频谱仪分子天文学

Application of deep learning methods combined with physical background in wide field of view imaging atmospheric Cherenkov telescopes

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Nuclear Science and Techniques 2024年第4期35卷 208-220页

作者： Ao-Yan Cheng Hao Cai Shi Chen Tian-Lu Chen Xiang Dong You-Liang Feng Qi Gao Quan-Bu Gou Yi-Qing Guo Hong-Bo Hu Ming-Ming Kang Hai-Jin Li Chen Liu Mao-Yuan Liu wei Liu Fang-Sheng Min Chu-Cheng Pan Bing-Qiang Qiao Xiang-Li Qian Hui-Ying Sun Yu-Chang Sun Ao-Bo Wang xu Wang Zhen Wang Guang-Guang Xin Yu-Hua Yao Qiang Yuan Yi Zhang School of Physics and Technology Wuhan UniversityWuhan 430072China School of Physics and Astronomy Yunnan UniversityKunming 650091China Ministry of Education The Key Laboratory of Cosmic Rays(Tibet University)Lhasa 850000China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of sciences 19 A Yuquan RoadShijingshan DistrictBeijing 100049China College of Physics Sichuan UniversityChengdu 610064China School of Intelligent Engineering Shandong Management UniversityJinan 250357China Tsung‑Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China Suzhou Aerospace Information Research Institute Suzhou 215123China College of Physics Chongqing UniversityNo.55 Daxuecheng South RoadHigh‑tech DistrictChongqing 401331China Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210008China

The High Altitude Detection of Astronomical Radiation(HADAR)experiment,which was constructed in Tibet,china,combines the wide-angle advantages of traditional EAS array detectors with the high-sensitivity advantages of focused Cherenkov *** objective is to observe transient sources such as gamma-ray bursts and the counterparts of gravitational *** study aims to utilize the latest AI technology to enhance the sensitivity of HADAR *** datasets and models with distinctive creativity were constructed by incorporating the relevant physical theories for various *** models can determine the type,energy,and direction of the incident particles after careful *** obtained a background identification accuracy of 98.6%,a relative energy reconstruction error of 10.0%,and an angular resolution of 0.22°in a test dataset at 10 *** findings demonstrate the significant potential for enhancing the precision and dependability of detector data analysis in astrophysical *** using deep learning techniques,the HADAR experiment’s observational sensitivity to the Crab Nebula has surpassed that of MAGIC and *** energies below 0.5 TeV and remains competitive with conventional narrow-field Cherenkov telescopes at higher *** addition,our experiment offers a new approach for dealing with strongly connected,scattered data.

关键词： VHE gamma-ray astronomy HADAR Deep learning Convolutional neural networks