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Frontiers of Information Technology & Electronic Engineering 2021年第4期22卷 571-585页

作者： Tao ZHOU Guichao CHEN Cheng-xiang WANG Jiayi ZHANG Liu LIU Yiqun LIANG School of Electronics and Information Engineering Beijing Jiaotong UniversityBeijing 100044China Center of National Railway Intelligent Transportation System Engineering and Technology China Academy of Railway SciencesBeijing 100081China National Mobile Communications Research laboratory School of Information Science and EngineeringSoutheast UniversityNanjing 210096China Purple Mountain Laboratories Nanjing 211111China

In this study,we consider a multi-cell millimeter-wave(mmWave)massive multiple-input multiple-output(MIMO)system with a mixed analog-to-digital converter(mixed-ADC)and hybrid beamforming architecture,in which antenna selection is applied to achieve intelligent assignment of high-and low-resolution *** exact and approximate closed-form expressions for the uplink achievable rate are derived in the case of maximum-ratio combining *** impacts on the achievable rate of user transmit power,number of radio frequency chains at a base station,ratio of high-resolution ADCs,number of propagation paths,and number of quantization bits are *** is shown that the user transmit power can be scaled down inversely proportional to the number of antennas at the base *** propose an efficient power allocation scheme by solving a complementary geometric programming *** addition,the energy efficiency is investigated,and an optimal tradeoff between the achievable rate and power consumption is *** results will provide a useful reference for the study of mixed-ADC multi-cell mmWave massive MIMO systems with antenna selection.

关键词： millimeter-wave Massive multiple-input multiple-output(MIMO) Mixed analog-to-digital converter Performance analysis Antenna selection

The ALMA-QUARKS Survey.Ⅱ.The ACA 1.3 mm Continuum Source Catalog and the Assembly of Dense Gas in Massive Star-Forming Clumps

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Research in Astronomy and Astrophysics 2024年第6期24卷 119-139页

作者：许峰玮 Ke Wang Tie Liu Lei Zhu Guido Garay Xunchuan Liu Paul Goldsmith Qizhou Zhang Patricio Sanhueza Shengli Qin Jinhua He Mika Juvela Anandmayee Tej Hongli Liu Shanghuo Li Kaho Morii Siju Zhang Jianwen Zhou Amelia Stutz Neal JEvans Kee-Tae Kim Shengyuan Liu Diego Mardones Guangxing Li Leonardo Bronfman Ken’ichi Tatematsu Chang Won Lee Xing Lu Xiaofeng Mai Sihan Jiao James O.Chibueze keyun Su Viktor L.Tóth Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Departamento de Astronomía Universidad de ChileLas Condes7591245 SantiagoChile Jet Propulsion laboratory California Institute of Technology4800 Oak Grove DrivePasadena CA 91109USA Center for Astrophysics|Harvard&Smithsonian 60 Garden StreetCambridgeMA 02138USA National Astronomical Observatory of Japan National Institutes of Natural Sciences2-21-1 OsawaMitakaTokyo 181-8588Japan Astronomical Science Program The Graduate University for Advanced StudiesSOKENDAI2-21-1 OsawaMitakaTokyo 181-8588Japan School of Physics and Astronomy Yunnan UniversityKunming 650091China Yunnan Observatories Chinese Academy of SciencesKunming 650216China Department of Physics University of HelsinkiPO Box 64FI-00014 HelsinkiFinland Indian Institute of Space Science and Technology Thiruvananthapuram 695547KeralaIndia Max Planck Institute for Astronomy Königstuhl 17D-69117 HeidelbergGermany Department of Astronomy Graduate School of ScienceThe University of Tokyo7-3-1 HongoBunkyo-kuTokyo 113-0033Japan Max-Planck-Institut für Radioastronomie Auf dem Hügel 6953121 BonnGermany Departamento de AstronomÂıa Universidad de ConcepcionCasilla 160-CConcepci onChile Department of Astronomy The University of Texas at AustinTexas 78712-1205USA Korea Astronomy and Space Science Institute 776 Daedeokdae-roYuseong-guDaejeon 34055Republic of Korea Institute of Astronomy and Astrophysics Academia SinicaRoosevelt RoadTaipei 10617TaiwanChina South-Western Institute for Astronomy Research Yunnan UniversityKunming 650091China Korea Astronomy and Space Science Institute 776 Daedeok-daeroYuseong-guDaejeon 34055Republic of

Leveraging the high resolution,sensitivity,and wide frequency coverage of the Atacama Large millimeter/submillimeter Array(ALMA),the QUARKS survey,standing for“Querying Underlying mechanisms of massive star formation with ALMA-Resolved gas Kinematics and Structures”,is observing 139 massive starforming clumps at ALMA Band 6(λ~1.3 mm).This paper introduces the Atacama Compact Array(ACA)7 m data of the QUARKS survey,describing the ACA observations and data *** multiwavelength data,we provide the first edition of QUARKS atlas,offering insights into the multiscale and multiphase interstellar medium in high-mass star *** ACA 1.3 mm catalog includes 207 continuum sources that are called ACA *** gas kinetic temperatures are estimated using three formaldehyde transitions with a non-LTE radiation transfer model,and the mass and density are derived from a dust emission *** ACA sources are massive(16–84 percentile values of 6–160 M_(⊙)),gravity-dominated(M∝R^(1.1))fragments within massive clumps,with supersonic turbulence(M>1)and embedded star-forming *** find a linear correlation between the masses of the fragments and the massive clumps,with a ratio of 6%between the *** considering fragments as representative of dense gas,the ratio indicates a dense gas fraction(DGF)of 6%,although with a wide scatter ranging from 1%to 10%.If we consider the QUARKS massive clumps to be what is observed at various scales,then the size-independent DGF indicates a self-similar fragmentation or collapsing mode in protocluster *** the ACA data over four orders of magnitude of luminosity-to-mass ratio(L/M),we find that the DGF increases significantly with L/M,which indicates clump evolutionary *** observed a limited fragmentation at the subclump scale,which can be explained by a dynamic global collapse process.

关键词： stars:formation ISM:kinematics and dynamics ISM:clouds stars:protostars

AI-EMPOWERED millimeter WAVE COMMUNICATION AND NETWORKING

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China Communications 2020年第10期17卷 97-99页

作者： Wenjun Xu Chuan Huang Yongming Huang Chau Yuen Shuguang Cui Beijing Univ Posts & Telecommun BUPT Sch Artificial Intelligence Beijing Peoples R China Minist Educ Key Lab Universal Wireless Commun Beijing Peoples R China Arizona State Univ Tempe AZ USA Princeton Univ Princeton NJ 08544 USA Chinese Univ Hong Kong Shenzhen Hong Kong Peoples R China Southeast Univ Sch Informat Sci & Engn Nanjing Peoples R China Lucent Technol Bell Labs Murray Hill NJ USA Inst Infocomm Res I2R Singapore Singapore Singapore Univ Technol & Design Singapore Singapore Univ Arizona Elect & Comp Engn Tucson AZ 85721 USA Texas A&M Univ College Stn TX 77843 USA Univ Calif Davis Davis CA USA CUHK Shenzhen Peoples R China Shenzhen Res Inst Big Data Shenzhen Peoples R China

Thanks to the abundant and attractive spectrum resource in the millimeter-wave(mmWave)band,mmWave technologies have been widely applied to the fifth-generation(5G)mobile communication system and will continuously evolve towards the future beyond 5G systems as ***,achieving the pervasive application of mmWave for 5G and beyond still faces many challenges,for example,the severe path-loss and vulnerability in blockage of mmWave propagation may have a great impact on mmWave communication and networking.

关键词： beyond communication millimeter

Iodine-assisted ultrafast growth of high-quality monolayer MoS_(2) with sulfur-terminated edges

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National Science Open 2023年第4期2卷 43-54页

作者： Qinke Wu Jialiang Zhang Lei Tang Usman Khan Huiyu Nong Shilong Zhao Yujie Sun Rongxu Zheng Rongjie Zhang Jingwei Wang Junyang Tan Qiangmin Yu Liqiong He Shisheng Li Xiaolong Zou Hui-Ming Cheng Bilu Liu Shenzhen Geim Graphene Center Tsinghua-Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Institute of Functional Porous Materials School of Materials Science and EngineeringZhejiang Sci-Tech UniversityHangzhou 310018China International Center for Materials Nanoarchitectonics National Institute for Materials ScienceTsukuba 305-0044Japan Faculty of Materials Science and Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Shenyang National laboratory for Materials Sciences Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Advanced Technology Institute University of SurreyGuildfordSurrey GU27XHUK

Two-dimensional(2D)semiconductors have attracted great attention to extend Moore’s law,which motivates the quest for fast growth of high-quality ***,taking MoS_(2) as an example,current methods yield 2D MoS_(2) with a low growth rate and poor quality with vacancy concentrations three to five orders of magnitude higher than silicon and other commercial ***,we develop a strategy of using an intermediate product of iodine as a transport agent to carry metal precursors efficiently for ultrafast growth of high-quality MoS_(2).The grown MoS_(2) has the lowest density of sulfur vacancies(~1.41×10^(12) cm^(−2))reported so far and excellent electrical properties with high on/off current ratios of 108 and carrier mobility of 175 cm^(2) V^(−1) s^(−1).Theoretical calculations show that by incorporating iodine,the nucleation barrier of MoS_(2) growth with sulfur-terminated edges reduces *** sufficient supply of precursor and low nucleation energy together boost the ultrafast growth of sub-millimeter MoS_(2) domains within *** work provides an effective method for the ultrafast growth of 2D semiconductors with high quality,which will promote their applications.

关键词： 2D semiconductors molybdenum disulfides ultrafast growth defect density sulfur vacancy iodine-assisted sulfur-terminated edge

Normal Physics Model of an Aerial Remote Sensing Platform and Systemic Accuracy Assessment of a Variable Baseline-Height Ratio

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Journal of Geodesy and Geoinformation Science 2019年第1期 72-72页

作者： Lei YAN Zhengkang ZUO Yingcheng LI Xiuxiao YUAN Yan SONG Qingsheng XUE Shihu ZHAO Institute of Remote Sensing and Geographic Information System Beijing Key Lab.of Spatial Information Integration and its ApplicationPeking University Chinese Academy of Surveying and Mapping China TOPRS Technology Co.Ltd. School of Remote Sensing and Information Engineering Wuhan University Faculty of Information Engineering China University of Geosciences Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences Satellite Surveying and Mapping Application Center NASG

Accuracy is a key factor in high-resolution remote sensing and photogrammetry. The factors that affect accuracy are imaging system errors and data processing errors. Due to the complexity of aerial camera errors,this paper focuses on the design of digital aerial camera systems and the means to reduce system error and data processing inefficiencies. There are many kinds of digital aerial camera systems at present; however,these systems lack a unified physical model,which ultimately leads to more complicated designs and multi-camera modes. Such a system is complex and costly,as it is easily affected by factors such as vibration and temperature. Thus,the installed accuracy can only reach the millimeter level. Here,we describe a unified physical structure for a digital aerial camera that imitates an out-of-field multi-charge-coupled device (CCD),an in-field multi-CCD,and once-imaging and twice-imaging digital camera systems. This model is referred to as the variable baseline-height ratio spatiotemporal model. The variable ratio allows the opto-mechanical spatial parameters to be linked with height accuracy,thus providing a connection to the surface elevation. The twice-imaging digital camera prototype system and the wideband limb imaging spectrometer provide a transformation prototype from the current multi-rigid once-imaging aerial camera to a single rigid ***,our research lays a theoretical foundation and prototype references for the construction and industrialization of digital aerial systems.

关键词： Normal Physics Model of an Aerial Remote Sensing Platform and Systemic Accuracy Assessment of a Variable Baseline-Height Ratio Model