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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 Nanjing 210008 China

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

紫金山天文台4.5—7.5 GHz太阳快速频谱仪图像

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天文学报 2003年第4期44卷 355-362页

作者：金乐春吴洪敖许富英孟璇中国科学院紫金山天文台南京210008 中国科学院国家天文台北京100012

运用多种方法,对紫金山天文台4.5—7.5 GHz太阳快速频谱仪获得的太阳微波爆发频谱图像进行后续处理,尽可能地去除噪声和干扰,还原爆发事件的本来面目,并突出感兴趣的部分,在MATLAB的平台支持下编写了WINDOWS下的应用软件,取得了较为满... 详细信息

运用多种方法,对紫金山天文台4.5—7.5 GHz太阳快速频谱仪获得的太阳微波爆发频谱图像进行后续处理,尽可能地去除噪声和干扰,还原爆发事件的本来面目,并突出感兴趣的部分,在MATLAB的平台支持下编写了WINDOWS下的应用软件,取得了较为满意的结果.

关键词：紫金山天文台太阳频谱仪射电辐射仪器光污染数据分析

A Dual-channel Millimeter Wave Radiometer

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A Dual-channel Millimeter Wave Radiometer

1997年3月9日日全食8.6mm波段射电观测

IEEE 2005 International Symposium on Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications

作者： L. wu1, S. S. Peng1 , X. H. Yin2, Z.C. xu2(1,E .Sys . Depart., nanjing Univ. of Sci. & Techn., nanjing, Jiangsu, P.R. china, 210094 (2,purple mountain observatory, nanjing, Jiangsu, P.R. china, 210008)

The paper describes a dual-channel millimeter wave radiometer system with high resolution, which is used to remotely sense integrated water vapor and integrated liquid water in the troposphere. A new

关键词： 8mm, 13mm, millimeter wave radiometer, integrated water vapor, integrated liquid water

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天体物理学报 1999年第1期19卷 97-103页

作者：吴洪敖周树荣查德元姚骑均许富英秦志海中国科学院紫金山天文台南京大学天文系

１９９７年３月９日日全食８．６ｍｍ波段射电观测资料的分析表明：８．６ｍｍ波段射电太阳的半径为１．０１２Ｒ，总流量为２５４０ｓｆｕ（１ｓｆｕ＝１０－２２Ｗ／ｍ２Ｈｚ），日面平均亮温度为９６３２Ｋ，径向亮温度分布，在日面... 详细信息

１９９７年３月９日日全食８．６ｍｍ波段射电观测资料的分析表明：８．６ｍｍ波段射电太阳的半径为１．０１２Ｒ，总流量为２５４０ｓｆｕ（１ｓｆｕ＝１０－２２Ｗ／ｍ２Ｈｚ），日面平均亮温度为９６３２Ｋ，径向亮温度分布，在日面光学边缘内侧０．９３６－０．９９２Ｒ处，存在临边增亮，平均增亮幅度相对于日面中心为９．７％．

关键词：日全食毫米波亮温度分布波段射电观测

All-silicon low-loss THz temporal differentiator based on microring waveguide resonator platform

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Light(Advanced Manufacturing) 2024年第2期5卷 14-23页

作者： Yunjie Rui Shuyu Zhou xuecou Tu xu Yan Bingnan Yan Chen Zhang Ziyao Ye Huilin Zhang Jingya Xie Qing-Yuan Zhao La-Bao Zhang Xiao-Qing Jia Huabing Wang Lin Kang Jian Chen Peiheng wu Research Institute of Superconductor Electronics(RISE) School of Electronic Science and EngineeringNanjing UniversityNanjingJiangsu 210023China Hefei National Laboratory Hefei 230088China purple mountain Laboratories NanjingJiangsu 211111China Terahertz Technology Innovation Research Institute Shanghai Key Lab of Modern Optical SystemUniversity of Shanghai for Science and TechnologyShanghai200093China

Microring resonators have been widely used in passive optical devices such as wavelength division multiplexers,differentiators,and *** on terahertz(THz)components has been accelerated by these photonics *** and integrated time-domain differentiators that enable low-loss,high-speed THz signal processing are necessary for THz *** this study,an on-chip THz temporal differentiator based on all-silicon photonic technology was *** device primarily consisted of a microring waveguide resonator and was packaged with standard waveguide *** performed time-domain differentiation on input signals at a frequency of 405.45 GHz with an insertion loss of 2.5 dB and a working bandwidth of 0.36 *** periodic waveforms could be handled by this *** device could work as an edge detector,which detected step-like edges in high-speed input signals through differential *** development holds significant promise for future THz data processing technologies and THz communication systems.

关键词： Silicon photonics Whispering gallery mode resonator THz silicon waveguide

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一种同步卫星授时方法

天文学报 1996年第2期37卷 147-153页

作者：徐劲宋金安张挥吴建民刘世茂中国科学院陕西天文台广州人造卫星观测站中国科学院紫金山天文台

本文简要分析了当前采用的各种时刻比对方法和技术，强调指出了静止卫星共视法在当前我国时刻比对工作中的实际应用价值，并对亚星一号进行了动力学定轨及时刻比对实验．实算结果表明：在现有的观测精度下，对亚星一号进行微分轨道改进... 详细信息

本文简要分析了当前采用的各种时刻比对方法和技术，强调指出了静止卫星共视法在当前我国时刻比对工作中的实际应用价值，并对亚星一号进行了动力学定轨及时刻比对实验．实算结果表明：在现有的观测精度下，对亚星一号进行微分轨道改进后，可使共视法比对的事后处理精度优于１μｓ，其预报精度在１—２天内可达１μｓ，在一个星期内也只有几个微秒．

关键词：定轨时刻比对同步卫星授时法动力学

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不同施肥制度下紫色土坡耕地氮素流失特征

水土保持学报 2005年第5期19卷 65-68页

作者：汪涛朱波武永锋况福虹徐泰平中国科学院成都山地灾害与环境研究所西南农业大学资环学院重庆400716

利用野外径流小区试验,比较了川中紫色土丘陵区12种不同施肥制度下坡耕地侵蚀产沙特征和氮素迁移特征。结果表明,在单次降雨量达到44 mm时,相对于不施肥而言,农家肥配施化肥分别降低坡地径流与侵蚀量68.2%,67.3%,秸秆还田配施化肥分别降... 详细信息

利用野外径流小区试验,比较了川中紫色土丘陵区12种不同施肥制度下坡耕地侵蚀产沙特征和氮素迁移特征。结果表明,在单次降雨量达到44 mm时,相对于不施肥而言,农家肥配施化肥分别降低坡地径流与侵蚀量68.2%,67.3%,秸秆还田配施化肥分别降低80.3%,92.6%。不同施肥制度下随地表径流迁移的颗粒态氮占总氮的比例大部分都在60.0%以上。坡耕地平衡施肥能降低坡耕地土壤氮素随径流的损失,增施了磷、钾肥后,总氮迁移量分别降低了41.0%和46.1%。与不施肥相比较,农家肥配施化肥减少径流总氮69.0%,秸秆还田配施化肥减少90.5%。

关键词：施肥制度紫色土坡耕地氮素流失

Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

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Science china(Physics,Mechanics & Astronomy) 2024年

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P. U. Fynbo Lluis Galbany Saurabh W. Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen wu xuefeng wu Dong xu Yanjun xu Suijian xue Yongquan xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu wu Haitao xu Jingjing xu Xinpeng xu Yunfei xu Zhao xu Changbin xue Yulong xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation academy for Microsatellites chinese academy of sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University National Astronomical Observatories Department of Physics Anhui Normal University Shanghai Institute of Technical Physics chinese academy of sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas chinese academy of sciences South African Astronomical observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Universite' Paris Cite' CNRS Astroparticule et Cosmologie Universite' Paris Cite' CEA Paris-Saclay School of Astronomy and Space sciences IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research University of chinese academy of sciences The University of Tokyo ESA/ESTEC Noordwijk 2201 AZ The Netherlands Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics Key Laboratory of Particle Astrophysics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology Hefei School of Astronomy and Space sciences University of Science and Technology of china Institute of High Energy Physics Institute of Deep Space sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical observatory chinese academy of Science

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 keV,300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for4d,followed by a steep decay till becoming undetectable10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词：

The spiral structure of the Milky Way

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Research in Astronomy and Astrophysics 2018年第12期18卷 9-28页

作者： Ye xu Li-Gang Hou Yuan-Wei wu purple mountain observatory Chinese Academy of Sciences CAS Key Laboratory of FAST National Astronomical Observatories Chinese Academy of Sciences National Astronomical Observatories Chinese Academy of Sciences National Time Service Center Key Laboratory of Precise Positioning and Timing Technology Chinese Academy of Sciences

The morphology and kinematics of the spiral structure of the Milky Way are long-standing problems in *** this review we firstly summarize various methods with different tracers used to solve this *** astrometry of Galactic sources is gradually alleviating this difficult situation caused mainly by large distance uncertainties, as we can currently obtain accurate parallaxes(a few μas) and proper motions(≈1 km s-1) by using Very Long Baseline Interferometry(VLBI).On the other hand, the Gaia mission is providing the largest, uniform sample of parallaxes for O-type stars in the entire Milky *** upon the VLBI maser and Gaia O-star parallax measurements, nearby spiral structures of the Perseus, Local, Sagittarius and Scutum Arms are determined in unprecedented ***, we estimate fundamental Galactic parameters of the distance to the Galactic center,R0, to be 8.35 ± 0.18 kpc, and circular rotation speed at the Sun, Θ0, to be 240±10 km *** found kinematic differences between O stars and interstellar masers: the O stars, on average, rotate faster,>8 km s-1than maser-traced high-mass star forming regions.

关键词： Galaxy:structure Galaxy:kinematics and dynamics masers techniques:high angular resolution astrometry stars:formation