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Space-to-Ground Quantum Key Distribution Using a Small-Sized Payload on Tiangong-2 Space Lab

chinese Physics Letters 2017年第9期34卷 18-23页

作者： Sheng-Kai Liao Jin Lin Ji-Gang Ren Wei-Yue Liu Jia Qiang Juan Yin Yang Li Qi Shen Liang Zhang Xue-Feng Liang Hai-Lin Yong Feng-Zhi Li Ya-Yun Yin Yuan Cao Wen-Qi Cai Wen-Zhuo Zhang Jian-Jun Jia Jin-Cai Wu Xiao-Wen Chen Shan-Cong Zhang Xiao-Jun Jiang Jian-Feng Wang Yong-Mei Huang Qiang Wang Lu Ma Li Li Ge-Sheng Pan Qiang Zhang Yu-Ao Chen Chao-Yang Lu Nai-Le Liu Xiongfeng Ma Rong Shu Cheng-Zhi Peng Jian-Yu Wang Jian-Wei Pan Department of Modern Physics and Hefei National Laboratory for Physical sciences at the Microscale University of Science and Technology of ChinaHefei 230026 Shanghai Branch CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum PhysicsShanghai 201315 Key Laboratory of Space Active Opto-Electronic Technology Shanghai Institute of Technical PhysicsChinese Academy of SciencesShanghai 200083 Beijing UCAS Space Technology Co. LtdBeijing 100190 National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 Key Laboratory of Optical engineering Institute of Optics and ElectronicsChinese Academy of SciencesChengdu 610209 Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011

Quantum technology establishes a foundation for secure communication via quantum key distribution （QKD）. In the last two decades, the rapid development of QKD makes a global quantum communication network feasible. In order to construct this network, it is economical to consider small-sized and low-cost QKD payloads, which can be assembled on satellites with different sizes, such as space stations. Here we report an experimental demonstration of space-to-ground QKD using a small-sized payload, from Tiangong-2 space lab to Nanshan ground station. The 57.9-kg payload integrates a tracking system, a QKD transmitter along with modules for synchronization, and a laser communication transmitter. In the space lab, a 50MHz vacuum＋weak decoy-state optical source is sent through a reflective telescope with an aperture of 200mm. On the ground station, a telescope with an aperture of 1200mm collects the signal photons. A stable and high-transmittance communication channel is set up with a high-precision bidirectional tracking system, a polarization compensation module, and a synchronization system. When the quantum link is successfully established, we obtain a key rate over 100bps with a communication distance up to 719km. Together with our recent development of QKD in daylight, the present demonstration paves the way towards a practical satellite-constellation-based global quantum secure network with small-sized QKD payloads.

关键词： QKD Space-to-Ground Quantum Key Distribution Using a Small-Sized Payload on Tiangong-2 Space Lab

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Annual Time-series Analyses of Total Gaseous Mercury Measurement and its Impact Factors on the Gongga Mountains in the Southeastern Fringe of the Qinghai-Tibetan Plateau

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Journal of Mountain Science 2008年第1期5卷 17-31页

作者： ZHU Wanze FU Xuewu FENG Xinbin Julia Y. Lu Institute of Mountain Hazard and Environment Chinese Academy of Sciences Chengdu 610041 China State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China Department of Chemistry and Biology Ryerson University Toronto Ontario M5B 2K3 Canada

Long-term monitoring programs for measurement of atmospheric mercury concentrations are presently recognized as powerful tools for local,regional and global studies of atmospheric long-range transport processes,and they could also provide valuable information about the impact of emission controls on the global budget of atmospheric mercury,their observance and an insight into the global mercury cycle. China is believed to be an increasing atmospheric mercury emission source. However,only a few measurements of mercury,to our knowledge,have been done in ambient air over China. The highly-time resolved atmospheric mercury concen-trations have been measured at Moxi Base Station (102°72′E 29°92′N,1640 m asl) of the Gongga Alpine Ecosystem Observation and Experiment Station of chinese academy of sciences (CAS) from May 2005 to June 2006 by using a set of Automatic Atmospheric Mercury Speciation Analyzers (Tekran 2537A). Measurements were carried out with a time resolution of every 15 minutes. The overall average total gaseous mercury (TGM) covering the measurement periods was 4±1.38 ng·m-3 (N=57310),which is higher than the global background level of approximately 1.5～2.0 ng·m-3. The measurements in all seasons showed a similar diurnal change pattern with a high concentration during daytime relative to nighttime and maximum concentration near solar noon and minimum concentration immediately before sunrise. The presence of diurnal TGM peaks during spring and summer was found earlier than that during autumn and winter. When divided seasonally,it was found that the concentrations of TGM were highest in winter with 6.13 ± 1.78 ng·m-3 and lowest in summer with 3.17 ± 0.67 ng·m-3. There were no significant differences in TGM among wind sectors during each season. Whereas Hg generally exhibited significant correlations with the parameters,such as temperature,saturated vapor pressure,precipitation,ultraviolet radiation (UV) and atmospheric pressure at the whole measurement stage,

关键词： Total gaseous mercury (TGM) diurnal variability seasonal variability meteorological factor Gongga Mountains

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The westerly fluctuation and water vapor transport over the Qilian-Heihe valley

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Science China Earth sciences 2004年第z1期47卷 32-38页

作者： WANG Keli CHENG Guodong XIAO Honglang JIANG Hao Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

The westerly fluctuation and the atmospheric water vapor transport over the Qilian-Heihe valley are analyzed and the results show that, in the water vapor transport stream field from Jun to September, this valley is in the westerly stream and the water vapor comes from westerlies water transport via the Black Sea and the Caspian Sea. The net water vapor transport is less net import and different from most areas of the northwest China. The interannual changes in water vapor transport over the valley arise from the westerly fluctuation, and have a positive relationship to the interannual changes in westerly wind speed. The cold air actions from the Mongol low pressure are the primary system that controls the westerly water vapor transport. Its action chain is that, the Mongol low pressure is strengthened → the circulation meridionality will be increased → the cold air will move southwards → the westerly will be stronger → the wind convergence of direction and speed will be stronger → the water vapor convergence transport will be increased → the local water vapor content will be increased. The interannual changes in atmospheric water vapor transport over the valley rely mainly on the convergence transport, but the effect of advection transport is less. The interannual changes of strong or weak westerly affect mainly the convergence transport, and then make the atmospheric water vapor net transport increase or decrease over the Qilian-Heihe valley.

关键词： waler vapor transport westerly fluctuation Qilian-Heihe valley northwest China water resource.

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Stem and leaf traits as co-determinants of canopy water flux

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Plant Diversity 2019年第4期41卷 258-265页

作者： Jianguo Gao Kai Tian Department of Ecology College of Urban and Environmental SciencesKey Laboratory for Earth Surface Processes of the Ministry o f EducationPeking UniversityNo.5 Yiheyuan Road Haidian DistrictBeijing100871PR China School of Life sciences Nanjing UniversityNanjing210023PR China Coastal Ecosystems Research Station of the Yangtze River Estuary Ministry of Education Key Laboratory for Biodiversity Science and Ecological EngineeringInstitute of Biodiversity ScienceFudan UniversityShanghai200438PR China Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems Chinese Academy o f SciencesSouth China Botanical GardenGuangzhou510650PR China

Transpiration through stomata in tree canopies plays an important role in terrestrial water ***, the empirical relationship between leaf stomata anatomy and canopy stomatal conductance（Gs） is surprisingly rare, thereby the underlying biological mechanisms of terrestrial water flux are not well elucidated. To gain further insight into these mechanisms, we reanalyzed the dataset of Gspreviously reported by Gao et al.（2015） using a quantile regression model. The results indicated that the reference Gs(Gsref, Gs at 1 kPa) was negatively correlated with wood density at each quantile, which confirmed previous data; however, Gsrefwas significantly correlated with stomatal density at the 0.6 quantile, i.e., 450 stomata mm-2. This highlighted the potential of using stomatal density as a trait to predict canopy water flux. A conceptual model of co-determinants of xylem and stomatal morphology suggests that these traits and their coordination may play a critical role in determining tree growth,physiological homeostatic response to environmental variables, water use efficiency, and drought resistance.

关键词： Gsref Quantile regression Stomatal density Water flux Wood density

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Preliminary reconstruction of the desert and sandy land distributions in China since the last interglacial period

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Science China Earth sciences 2004年第z1期47卷 89-100页

作者： CHEN Huizhong, SU Zhizhu, YANG Ping & DONG GuangrongKey Laboratory of Desert and Desertification, Cold and Arid Regions Environmental and Engineering Research Institute, chinese academy of sciences, Lanzhou 730000, China State Key Laboratory of Loess Quaternary Geology, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, China Institute of Loess Plateau, Shanxi University, Taiyuan 030006, China 1. Key Laboratory of Desert and Desertification Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences 730000 Lanzhou China 2. State Key Laboratory of Loess Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences 710075 Xi’an China 3. Institute of Loess Plateau Shanxi University 030006 Taiyuan China

The desert and sandy land are the products of arid climate. The spatial distribution of modern deserts and sandy land in China and their relation to climate show following characteristics: arid and hyper-arid desert zones, at isohyet of less than 200 mm, are dominated by mobile dunes; semi-arid steppe and arid desert steppe with the precipitation between 200?00 mm, are dominated by semi-fixed and fixed sand dunes; the precipitation of sub-humid forest grassland and humid forest zones with scattered fixed sand land is higher than 400 mm. With this as reference, in combination with considerable amount of paleoclimatic data in desert regions and adjacent regions, the distributions of desert and sandy land in China during the last intergla-cial period, the last glacial maximum (LGM), and the Holocene megathermal, were preliminarily reconstructed. The results compared with that of today show that the distribution of desert and sandy land in China was greatly dwindled during last interglacial period, and the mobile dune area was about two-thirds of that of today's, but greatly expanded during LGM. However, the dwindling area of desert and sandy land in the Holocene megathermal was smaller than that in the last interglacial period. The forcing mechanism was mainly related to the changes of East Asian winter and summer monsoon, south-northward swing of the westerlies and the variations of the Qinghai-Tibet Plateau monsoon intensity caused by global climate changes during the cold and warm intervals since the last interglacial period.

关键词： the glacial-interglacial period, desert, sandy land, spatial distribution.

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Safeguarding our future by protecting biodiversity

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Plant Diversity 2020年第4期42卷 221-228页

作者： Richard T.Corlett Center for Integrative Conservation Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglaYunnan666303China Center of Conservation Biology Core Botanical GardensChinese Academy of SciencesMenglaYunnan666303China

The Anthropocene is marked by twin crises:climate change and biodiversity *** change has tended to dominate the headlines,reflecting,in part,the greater complexity of the biodiversity *** itself is a difficult *** plants dominate the global biomass and terrestrial arthropods probably dominate in terms of numbers of species,but most of the Tree of Life consists of single-celled eukaryotes,bacteria,and *** plants provide a huge variety of products and services to people,ranging from those that are species-specific,such as food,medicine,and genetic resources,to many which are partly interchangeable,such as timber and forage for domestic animals,and others which depend on the whole community,but not on individual species,such as regulation of water supply and carbon *** use of information from remote sensing has encouraged a simplified view of the values of nature's contributions to people,but this does not match the way most people value *** can currently estimate the proportion of species threatened by human impacts only for a few well-assessed groups,for which it ranges from 14%(birds)to 63%(cycads).Less than 8%of land plants have been assessed,but it has been estimated that 30e44%are threatened,although there are still few(0.2%)well-documented *** for improving protection of biodiversity include:improving the inventory,with surveys focused on geographical areas and taxonomic groups which are under-collected;expanding the protected area system and its representativeness;controlling overexploitation;managing invasive species;conserving threatened species ex situ;restoring degraded ecosystems;and controlling climate *** Convention on Biological Diversity(CBD)COP15 and the United Nations Framework Convention on Climate Change(UNFCCC)COP26 meetings,both postponed to 2021,will provide an opportunity to address both crises,but success will require high ambition from all participants.

关键词： Anthropocene Climate change Conservation Ecosystem services Values

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One-step electrochemical fabrication of bilayered MgO/polymer coating on magnesium alloy

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Frontiers of Materials Science 2014年第3期8卷 307-312页

作者： Jun LIANG Ren-Hui ZHANG Zhen-Jun PENG Bai-Xing LIU State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China

This research demonstrates a novel one-step electrochemical method to fabricate thick bilayer coatings on magnesium alloy in acid phosphate electrolyte containing aniline monomer and styrene-acrylic emulsion （SAE） with pulsed DC voltage, The morphologies, XRD and FTIR results show that the bilayer coating consists of an inner oxide layer and an outer polyaniline （PANI）/SAE composite layer, It is believed that the bilayered structure achieved results from a hybrid process combining electropoly-merization （EPM） of aniiine, electrophoretic deposition （EPD） of SAE and plasma electrolyte oxidation （PEO） of magnesium alloy substrate. Electrochemical corrosion tests indicate that the bilayer coating can provide superior corrosion protection to the magnesium alloy substrate in 3.5 wt.% NaCl solution.

关键词： magnesium alloy bilayer coating EPD PEO corrosion resistance

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Variation characteristics of heavy metals and nutrients in the core sediments of Taihu Lake and their pollution history

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Science China Earth sciences 2006年第z1期49卷 82-91页

作者： LIU Enfeng SHEN Ji LIU Xingqi ZHU Yuxin WANG Sumin Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China Nanjing Institute of Geography & Limnology Chinese Academy of Sciences Nanjing 210008 China

The sedimentary environment change, trophic evolution and heavy metals pollution history of the northern Taihu Lake in the last 100 years are studied according to the sedimentary geochemical proxies of the core sediments, such as grain size, nutrients, heavy metals, diatom, etc. The nutrients in the sediments depended mainly on the lake internal circulation and the heavy metals were from natural geogenic sources before the 1920s, which were not influenced by human activities generally, and grain size was one of the key factors influencing heavy metals content in the *** alternation of manner and strength of human activities in Taihu Lake catchment before and after the 1920s made the lake sediments coarser, and hence heavy metals and TP content decreased contrasted with that before the 1920s. TP content in sediments and water increased from the 1950s to late 1970s due to anthropogenic pollutants discharge, and the lake belonging to mesotrophic *** and TOC content and C/N ratio increased due to the increasing external pollutants into Taihu Lake by human activities, TP content also increased obviously in water and sediments, and the diatom association was dominated by eutrophic species since the late 1970s, indicating the eutrophication state of Taihu Lake in this period. Meanwhile the increasing in heavy metals content, such as Cu, Mn,Ni, Pb and Zn, and their proportion of valid fractions in the sediments indicates that they all result from human pollutants since the late 1970s. The heavy metals in the surface sediments have certain potential biological toxicity due to the higher SEM/AVS ratio.

关键词： sediments, heavy metals, nutrients, human activities, pollution history, Taihu Lake.

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Relationship　between　global　seismicity　and　solar　activities

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Acta Seismologica Sinica(English Edition) 1998年第4期11卷 495-500页

作者： Gui-Qing Zhang (1) 1. Beijing Astronomical Observatory Chinese Academy of Science 100101 Beijing China

ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｇｌｏｂａｌｓｅｉｓｍｉｃｉｔｙａｎｄｓｏｌａｒａｃｔｉｖｉｔｉｅｓＧＵＩ－ＱＩＮＧＺＨＡＮＧ（张桂清）ＢｅｉｊｉｎｇＡｓｔｒｏｎｏｍｉｃａｌＯｂｓｅｒｖａｔｏｒｙ，Ｃｈｉｎｅｓ... 详细信息

ＲｅｌａｔｉｏｎｓｈｉｐｂｅｔｗｅｅｎｇｌｏｂａｌｓｅｉｓｍｉｃｉｔｙａｎｄｓｏｌａｒａｃｔｉｖｉｔｉｅｓＧＵＩ－ＱＩＮＧＺＨＡＮＧ（张桂清）ＢｅｉｊｉｎｇＡｓｔｒｏｎｏｍｉｃａｌＯｂｓｅｒｖａｔｏｒｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅ...

关键词： solar activity sunspot numbers solar radio flux solar proton events

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Probing into the Possible Range of the U Bosonic Coupling Constants in Neutron Stars Containing Hyperons

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Research in Astronomy and Astrophysics 2023年第5期23卷 180-189页

作者： Yan Xu Bin Diao Yi-Bo Wang Xiu-Lin Huang Xing-Xing Hu Zi Yu Changchun Observatory National Astronomical ObservatoriesChinese Academy of SciencesChangchun 130117China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 100049China College of Science Nanjing Forestry UniversityNanjing 210037China

The range of the U bosonic coupling constants in neutron star matter is a very interesting but still unsolved problem which has multifaceted influences in nuclear physics,particle physics,astrophysics and *** combination of the theoretical numerical simulation and the recent observations provides a very good opportunity to solve this *** the present work,the range of the U bosonic coupling constants is inferred based on the three relations of the mass–radius,mass-frequency and mass-tidal deformability in neutron stars containing hyperons using the GM1,TM1 and NL3 parameter sets under the two flavor symmetries of SU(6)and SU(3)in the framework of the relativistic mean field *** with observations from PSRs J1614-2230,J0348+0432,J2215-5135,J0952-0607,J0740+6620,J0030-0451,J1748-2446ad,XTE J1739-285,GW170817 and GW190814 events,our numerical results show that the U bosonic coupling constants may tend to be within the range from 0 to 20 GeV^(-2)in neutron star containing ***,the numerical results of the three relations obtained by the SU(3)symmetry are better in accordance with observation data than those obtained by the SU(6)*** results will help us to improve the strict constraints of the equation of state for neutron stars containing hyperons.

关键词： stars neutron-stars interiors-stars luminosity function-mass function-stars massive-dense matter-equation of state-gravitational waves

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