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Nature Cities 2024年 695-705页

作者： Chenxi Lu Felix Creutzig Jiawei Hu Yingjian Huang Huibin Mo Ying Yu Yun Li Da Huo Xuanren Song Xiaoting Huang Zhu Liu Yun Sun Kai Liu Shaohui Zhang Karyn Morrissey Jinpyo Hong Zhu Deng Zhuanjia Du Mercator Research Institute on Global Commons and Climate Change Berlin Germany Sustainability Economics of Human Settlements Technical University Berlin Berlin Germany Belfer Center for Science and International Affairs Harvard Kennedy School Harvard University Cambridge MA USA Alibaba Cloud Hangzhou China Guangdong Key Laboratory for Urbanization and Geo-simulation School of Geography and Planning Sun Yat-sen University Guangzhou China Shenzhen Key Laboratory of Ecological Remediation and Carbon Sequestration Institute of Environment and Ecology Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen China Data-Driven EnviroLab Department of Public Policy University of North Carolina at Chapel Hill Chapel Hill NC USA Department of Environmental Sciences and Engineering Gillings School of Global Public Health University of North Carolina at Chapel Hill Chapel Hill NC USA Faculty of Engineering Science Department of Architecture KU Leuven Leuven Belgium Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modeling Institute for Global Change Studies Tsinghua University Beijing China Department of Civil & Mineral Engineering University of Toronto Toronto Ontario Canada School of Environmental Science and Engineering Tianjin University Tianjin China Department of Geography King’s College London London UK Guangdong Holdings Limited Guangzhou China International Institute for Applied Systems Analysis (IIASA) Laxenburg Austria Division for Climate and Energy Policy Department of Technology Management and Economics Technical University of Denmark Lyngby Denmark School of Engineering Brown University Providence RI USA Department of Geography University of Hong Kong Hong Kong SAR China Department of Political Science Columbia University New York NY USA

Post-pandemic green recovery is pivotal in achieving global sustainable development goals by simultaneously revitalizing economies and reducing greenhouse gas emissions, air pollution and improving public welfare. However, subnational and city-level understanding of green recovery, its efficacy and its alignment with public health is poorly understood. Here we focus on post-COVID-19 low-carbon recovery—economic growth combined with reduced carbon emissions—and explore health co-benefits in Chinese cities. A novel near-real-time daily carbon emission dataset of 48 cities in China is developed, coupled with detailed health and economic municipal statistics and models. We find that, on average, six low-carbon-recovery cities, mainly megacities, saved 1.2 times as many lives per 100,000 population compared with the 42 other cities, and their annual monetary avoided premature deaths per 100,000 population was 1.5 times more than the 42 other cities. The accumulated monetary health co-benefits for low-carbon-recovery cities were US$ 4.2 billion (95% confidence interval, 2.1–6.3) during the post-COVID-19 period. We show that government spending on electric vehicles increases the likelihood of achieving low-carbon recovery in Chinese cities. Our results underscore the significant health co-benefits of low-carbon recovery, pointing to synergies between advancing local welfare and global environmental objectives.

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Application of a physically based radar rainfall system over Southwest China

Application of a physically based radar rainfall system over...

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IEEE International Geoscience and Remote Sensing Symposium

作者： Yabin Gou Haonan Chen Jieying He Qiulei Xia Hangzhou Meteorological Bureau and Zhejiang Institute of Meteorological Sciences Hangzhou China NOAA/Earth System Research Laboratory Colorado State University Colorado USA Key Laboratory of Microwave Remote Sensing National Space Science Center Beijing China Chengdu University of Information Technology Chengdu China

Quantitative Precipitation Estimation (QPE) is one of the most important applications of weather radars. However, it is difficult to obtain an optimal Z-R relation that can represent the local variability in precipitation microphysics. This study implements an adaptive radar QPE scheme based on the Storm Cell Identification and Tracking (SCIT) algorithm for Doppler radar and rain gauge measurements from Southwest China. The performance of this innovative QPE system is demonstrated using four precipitation events featured by different meteorological characteristics. Evaluation results show that the SCIT-based rainfall approach performs better than conventional Z-R based algorithms.

关键词： Doppler radar Reflectivity Meteorological radar Rain Radar tracking Storms

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Product Service system-based Municipal Solid Waste circular management platform in Campania Region (Italy): a preliminary analysis

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Procedia CIRP 2019年 83卷 224-229页

作者： Marco Casazza Donald Huisingh Sergio Ulgiati Vincenzo Severino Gengyuan Liu Massimiliano Lega Parthenope University of Napoli Department of Engineering Centro Direzionale Isola C4 80143 Naples Italy Parthenope University of Napoli Department of Science and Technology Centro Direzionale Isola C4 80143 Naples Italy University of Tennessee The Institute for a Secure and Sustainable Environment Knoxville TN USA State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China Beijing Engineering Research Center for Watershed Environmental Restoration & Integrated Ecological Regulation Beijing 100875 China

The huge amount of Municipal Solid Waste (MSW) generated in the world, as well as the adverse impacts on resources depletion, environmental contamination and human health are problems that need to be promptly, effectively and equitably addressed. Among the areas affected by management misconduct and illicit interests, the Campania region represents a paradigmatic case. A lack of detailed information about MSW flows, from collection and through treatment phases, prevents policy-makers and planners from finding appropriate and environmentally and economically sound solutions. As a partial approach to the solution, the authors of this paper outline the structure and functions of a Product Services system (PSS) based MSW management platform. In particular, data collection and elaboration, documentation of MSW flows and detection of environmental and human health impacts and waste prevention/reduction are essential elements of MSW of the system, within which the PSSs can be applied. Real-time sensors, big data analysis tools and online platforms are integrated, as basic tools, to implement the transition to equitable, sustainable circular economies. The solutions will be based upon multi-stakeholder inputs in decision-making to effectively address local needs to implement a re-designed, adaptive, dynamic, MSW management system. The new system must ensure safe and ecologically sound management of the resources in MSWs. As the new management system provides improvements in the environmental and human health and results in an expansion of jobs, it is anticipated that the system could also be useful in other parts of the world.

关键词： waste management circular economy product-service system

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Synergetic Lipid Extraction with Oxidative Damage Amplifies Cell-Membrane-Destructive Stresses and Enables Rapid Sterilization

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Angewandte Chemie 2020年第14期133卷

作者： Dr. Yu Chen Dr. Qinghua Ji Dr. Gong Zhang Prof. Huijuan Liu Prof. Jiuhui Qu Center for Water and Ecology State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Key Laboratory of Drinking Water Science and Technology Research Centre for Eco- Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China

Here, we introduce an innovative “poison arrowhead” approach for disinfection based on a nanosheet bacterial inactivation system that acts synergistically to achieve sterilization rates of >99.99 % ( Escherichia coli ) over an ultrashort time period (≈0.5 min). The two-dimensional MoS 2 “arrowhead” configuration has a sharp edge structure that enables the vigorous extraction of lipids from cell membranes and subsequent membrane disruptions. In the presence of permonosulfate, a strong oxidant, sulfur vacancies containing MoS 2 activate the stable molecules, which in turn produce reactive oxygen species (ROS) from edge sites to basal areas. This process not only scavenges some portion of the phospholipids to allow for MoS 2 surface refreshment but also directly attacks proteins thereby inflicting further damage to injured cells and amplifying the cell-membrane-destructive stresses toward pathogenic microorganisms. With small amounts of the new material, we successfully disinfected natural water (≈99.93 % inactivation in terms of total bacteria) within 30 s.

关键词： Fenton-like reactions lipid extraction molybdenum disulfide rapid disinfection synergistic effect

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Erratum: “Fine Structures of Radio Bursts from Flare Star AD Leo with FAST Observations” (2023, ApJ, 953, 65)

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The Astrophysical Journal 2024年第1期969卷 73页

作者： Zhang, Jiale Tian, Hui Lu, Hongpeng Zarka, Philippe Louis, Corentin K Gao, Dongyang Sun, Xiaohui Yu, Sijie Chen, Bin Cheng, Xin Wang, Ke School of Earth and Space Sciences Peking University Beijing 100871 People’s Republic of China huitian@*** LESIA Observatoire de Paris Université PSL Sorbonne Université Université Paris Cité CNRS 92190 Meudon France USN Observatoire de Paris Université PSL Univ Orléans CNRS 18330 Nançay France School of Cosmic Physics DIAS Dunsink Observatory Dublin Institute for Advanced Studies Dublin 15 Ireland Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space Sciences Shandong University Weihai 264209 Shandong People’s Republic of China School of Physics and Astronomy Yunnan University Kunming 650500 People’s Republic of China Center for Solar-Terrestrial Research New Jersey Institute of Technology Newark NJ 07102 USA School of Astronomy and Space Science Nanjing University Nanjing 210093 People’s Republic of China Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University) Ministry of Education Nanjing 210093 People’s Republic of China Max Planck Institute for Solar System Research Göttingen 37077 Germany Kavli Institute for Astronomy and Astrophysics Peking University Beijing 100871 People’s Republic of China

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The enhanced X-ray Timing and Polarimetry mission—eXTP

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science China(Physics,Mechanics & Astronomy) 2019年第2期62卷 3-27页

作者： ShuangNan Zhang Andrea Santangelo Marco Feroci YuPeng Xu FangJun Lu Yong Chen Hua Feng Shu Zhang Sφren Brandt Margarita Hernanz Luca Baldini Enrico Bozzo Riccardo Campana Alessandra De Rosa YongWei Dong Yuri Evangelista Vladimir Karas Norbert Meidinger Aline Meuris Kirpal Nandra Teng Pan Giovanni Pareschi Piotr Orleanski QiuShi Huang Stephane Schanne Giorgia Sironi Daniele Spiga Jiri Svoboda Gianpiero Tagliaferri Christoph Tenzer Andrea Vacchi Silvia Zane Dave Walton ZhanShan Wang Berend Winter Xin Wu Jean J.M.in't Zand Mahdi Ahangarianabhari Giovanni Ambrosi Filippo Ambrosino Marco Barbera Stefano Basso Jörg Bayer Ronaldo Bellazzini Pierluigi Bellutti Bruna Bertucci Giuseppe Bertuccio Giacomo Borghi XueLei Cao Franck Cadoux Francesco Ceraudo TianXiang Chen Yu Peng Chen Jerome Chevenez Marta Civitani Wei Cui WeiWei Cui Thomas Dauser Ettore Del Monte Sergio Di Cosimo Sebastian Diebold Victor Doroshenko Michal Dovciak YuanYuan Du Lorenzo Ducci QingMei Fan Yannick Favre Fabio Fuschino JoséLuis Ga'lvez Min Gao MingYu Ge Olivier Gevin Marco Grassi QuanYing Gu YuDong Gu DaWei Han Bin Hong Wei Hu Long Ji ShuMei Jia WeiChun Jiang Thomas Kennedy Ingo Kreykenbohm Irfan Kuvvetli Claudio Labanti Luca Latronico Gang Li MaoShun Li Xian Li Wei Li ZhengWei Li Olivier Limousin HongWei Liu XiaoJing Liu Bo Lu Tao Luo Daniele Macera Piero Malcovati Adrian Martindale Malgorzata Michalska Bin Meng Massimo Minuti Alfredo Morbidini Fabio Muleri Stephane Paltani Emanuele Perinati Antonino Picciotto Claudio Piemonte JinLu Qu Alexandre Rachevski Irina Rashevskaya Jerome Rodriguez Thomas Schanz ZhengXiang Shen LiZhi Sheng JiangBo Song LiMing Song Carmelo Sgro Liang Sun Ying Tan Phil Uttley Bo Wang DianLong Wang GuoFeng Wang Juan Wang LangPing Wang YuSa Wang Anna L.Watts XiangYang Wen Jörn Wilms ShaoLin Xiong JiaWei Yang Sheng Yang YanJi Yang Nian Yu WenDa Zhang Gianluigi Zampa Nicola Zampa Andrzej A.Zdziarski AiMei Zhang ChengMo Zhang Fan Zhang Long Zhang Tong Zhang Yi Zhang XiaoLi Zhang ZiLiang Zhang BaoSheng Zhao ShiJie Zheng Yu Peng Zhou Key Laboratory for Particle Astrophysics Institute of High Energy PhysicsChinese Academy of Sciences Institut für Astronomie und Astrophysik Eberhard Karls Universität INAF-Istituto di Astrofisica e Planetologia Spaziali INFN-Roma Tor Vergata Via della Ricerca Scientifica 1 Department of Engineering Physics and Center for Astrophysics Tsinghua University DTU Building 327DK-2800 Kongens Institute of Space Sciences 08193 Cerdanyola del Valles Institut d’Estudis Espacials de Catalunya Sezione di Pisa Istituto Nazionale di Fisica NucleareLargo Bruno Pontecorvo3 Department of Astronomy University of Genevachemin d’Ecogia 16 Osservatorio di Astrofisica e Scienza Dello Spazio di Bologna Istituto Nazionale di Astofisica Astronomical Institute Czech Academy of Sciences Max Planck Institute for Extraterrestrial Physics Giessenbachstr.1 CEA Paris-Saclay/IRFU Beijing Institute of Spacecraft System Engineering CAST Osservatorio Astronomico di Brera Istituto Nazionale di Astofisica Space Research Center Polish Academy of Sciences Key Laboratory of Advanced Material Microstructure of Education Ministry of China Institute of Precision Optical EngineeringSchool of Physics Science and EngineeringTongji University Department of Physics and Center for Astrophysics Tsinghua University Universita’degli Studi di Udine Via delle Scienze 206 Mullard Space Science Laboratory University College London Department of Nuclear and Particle Physics University of Geneva SRON Netherlands Institute for Space Research Politecnico di Milano Sezione di Perugia Istituto Nazionale di Fisica Nucleare Dipartimento di Fisica e Chimica Fondazione Bruno Kessler Dr.Karl Remeis-Observatory and Erlangen Centre for Astroparticle Physics Universität Erlangen-Nürnberg University of Pavia Department of ElectronicsInformation and Biomedical Engineering and INFN Pavia Sezione di Torino Istituto Nazionale di Fisica NucleareVia Pietro Giuria1 Department of Physics and Astronomy University of Leicester Sezione di Trieste Istituto Nazionale di Fisica Nucleare

In this paper we present the enhanced X-ray Timing and Polarimetry mission—eXTP. eXTP is a space science mission designed to study fundamental physics under extreme conditions of density, gravity and magnetism. The mission aims at determining the equation of state of matter at supra-nuclear density, measuring effects of QED, and understanding the dynamics of matter in strong-field gravity. In addition to investigating fundamental physics, eXTP will be a very powerful observatory for astrophysics that will provide observations of unprecedented quality on a variety of galactic and extragalactic objects. In particular, its wide field monitoring capabilities will be highly instrumental to detect the electro-magnetic counterparts of gravitational wave *** paper provides a detailed description of:(1) the technological and technical aspects, and the expected performance of the instruments of the scientific payload;(2) the elements and functions of the mission, from the spacecraft to the ground segment.

关键词： X-ray instrumentation X-ray polarimetry X-ray timing space mission:eXTP

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Mapping essential urban land use categories in China(EULUC-China):preliminary results for 2018

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science Bulletin 2020年第3期65卷 182-187页

作者： Peng Gong Bin Chen Xuecao Li Han Liu Jie Wang Yuqi Bai Jingming Chen Xi Chen Lei Fang Shuailong Feng Yongjiu Feng Yali Gong Hao Gu Huabing Huang Xiaochun Huang Hongzan Jiao Yingdong Kang Guangbin Lei Ainong Li Xiaoting Li Xun Li Yuechen Li Zhilin Li Zhongde Li Chong Liu Chunxia Liu Maochou Liu Shuguang Liu Wanliu Mao Changhong Miao Hao Ni Qisheng Pan Shuhua Qi Zhehao Ren Zhuoran Shan Shaoqing Shen Minjun Shi Yimeng Song Mo Su Hoi Ping Suen Bo Sun Fangdi Sun Jian Sun Lin Sun Wenyao Sun Tian Tian Xiaohua Tong Yihsing Tseng Ying Tu Hong Wang Lan Wang Xi Wan Zongming Wang Tinghai Wu Yaowen Xie Jian Yang Jun Yang Man Yuan Wenze Yue Hongda Zeng Kuo Zhang Neng Zhang Tao Zhang Yu Zhang Feng Zhao Yichen Zheng Qiming Zhou Nicholas Clinton Zhiliang Zhu Bing Xu Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Tsinghua Urban Institute Tsinghua UniversityBeijing 100084China Center for Healthy Cities Institute for China Sustainable UrbanizationTsinghua UniversityBeijing 100084China Department of Land Air and Water ResourcesUniversity of CaliforniaDavisCA 95616-8627USA Department of Geological and Atmospheric Sciences Iowa State UniversityAmesIA 50011USA State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing 100101China AI for Earth Laboratory Cross-Strait InstituteTsinghua UniversityBeijing 100084China International Institute for Earth System Sciences Nanjing UniversityNanjing 210093China Research Center for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumchi 830011China Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China National Engineering Laboratory for Applied Technology in Forestry&Ecology in South China College of Life Science and TechnologyCentral South University of Forestry and TechnologyChangsha 410004China College of Surveying&Geo-Informatics Tongji UniversityShanghai 200092China Department of Urban Planning College of Architecture and Urban PlanningTongji UniversityShanghai 200092China Beijing Institute of Urban Planning Beijing 100045China Department of Urban Planning School of Urban DesignWuhan UniversityWuhan 430072China College of Earth Sciences Jilin UniversityChangchun 130061China Research Center for Digital Mountain and Remote Sensing Application Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China Institute of Remote Sensing and Geographic Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China Department of Urban and Regional Planning School of Geography and PlanningSun Yat-sen Univ

Land use reflects human activities on *** land use is the highest level human alteration on Earth,and it is rapidly changing due to population increase and *** areas have widespread effects on local hydrology,climate,biodiversity,and food production[1,2].However,maps,that contain knowledge on the distribution,pattern and composition of various land use types in urban areas,are limited to city *** mapping standard on data sources,methods,land use classification schemes varies from city to city,due to differences in financial input and skills of mapping *** address various national and global environmental challenges caused by urbanization,it is important to have urban land uses at the national and global scales that are derived from the same or consistent data sources with the same or compatible classification systems and mapping *** is because,only with urban land use maps produced with similar criteria,consistent environmental policies can be made,and action efforts can be compared and assessed for large scale environmental ***,despite of the fact that a number of urban-extent maps exist at global scales[3,4],more detailed urban land use maps do not exist at the same *** at big country or regional levels such as for the United States,China and European Union,consistent land use mapping efforts are rare[5,6](e.g.,https://***/open_land_use/).

关键词： EULUC-China 土地利用类型

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Hot-Electron-Induced Photothermal Catalysis for Energy-Dependent Molecular Oxygen Activation

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Angewandte Chemie 2020年第9期133卷

作者： Wei Zhang Dr. Yu Chen Dr. Gong Zhang Dr. Xiao Tan Dr. Qinghua Ji Dr. Zhaowu Wang Prof. Huijuan Liu Prof. Jiuhui Qu Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Center for Water and Ecology State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China University of Chinese Academy of Sciences Beijing 100049 China Guilin University of Technology Guilin 541006 China School of Physics and Engineering Henan University of Science and Technology Henan Key Laboratory of Photoelectric Energy Storage Materials and Applications Luoyang Henan 471023 China

Hot electrons activate reactants and reduce the activation energy barrier ( E a ) of a reaction through electron donation. However, a comprehensive understanding of the intrinsic driving force of this electron-donating effect is lacking, let alone the precise manipulation of electron donation processes. Herein, the essential and promotional role of hot electron energy on the electron-donating effect was elucidated using molecular oxygen activation (MOA) as a model reaction. Through providing an available electron source to the conventional photo-thermal conversion system, the high energy carried by hot electrons was liberated and greatly enhanced the electron donation towards the LUMO (π*) orbit of O 2 . The energy was also transferred to O 2 and elevated the potential energy surface (PES) of MOA, which was reflected by the enhanced formation of superoxide oxygen anions. As predicted, the E a of MOA decreased by 45.1 % and exhibited a substantial light dependence, demonstrating that MOA became energy-efficient due to improved exploitation and conversion of photon energies.

关键词： activation barrier energy transfer hot electron molecular oxygen activation (MOA) photothermal catalysis

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First unambiguous detection of ammonia in the atmosphere of a planetary mass companion with JWST/MIRI coronagraphs

arXiv

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arXiv 2024年

作者： Mâlin, Mathilde Boccaletti, Anthony Perrot, Clément Baudoz, Pierre Rouan, Daniel Lagage, Pierre-Olivier Waters, Rens Güdel, Manuel Henning, Thomas Vandenbussche, Bart Absil, Olivier Barrado, David Charnay, Benjamin Choquet, Elodie Cossou, Christophe Danielski, Camilla Decin, Leen Glauser, Adrian M. Pye, John Olofsson, Goran Glasse, Alistair Patapis, Polychronis Royer, Pierre Scheithauer, Silvia Serabyn, Eugene Tremblin, Pascal Whiteford, Niall van Dishoeck, Ewine F. Ostlin, Göran Ray, Tom P. Wright, Gillian Department of Physics & Astronomy Johns Hopkins University 3400 N. Charles Street BaltimoreMD21218 United States Space Telescope Science Institute 3700 San Martin Drive BaltimoreMD21218 United States LIRA Observatoire de Paris Université PSL Sorbonne Université Université Paris Cité CY Cergy Paris Université CNRS Meudon92190 France Université Paris-Saclay Université Paris Cité CEA CNRS AIM Gif-sur-Yvette91191 France Department of Astrophysics IMAPP Radboud University PO Box 9010 Nijmegen6500 GL Netherlands HFML FELIX. Radboud University PO box 9010 Nijmegen6500 GL Netherlands SRON Netherlands Institute for Space Research Niels Bohrweg 4 Leiden2333 CA Netherlands Department of Astrophysics University of Vienna Türkenschanzstrasse 17 Vienna1180 Austria ETH Zürich Institute for Particle Physics and Astrophysics Wolfgang-Pauli-Strasse 27 Zürich8093 Switzerland Königstuhl 17 Heidelberg69117 Germany Institute of Astronomy KU Leuven Celestijnenlaan 200D Leuven3001 Belgium STAR Institute Université de Liège Allée du Six Août 19c Liège4000 Belgium CSIC-INTA ESAC Campus Camino Bajo del Castillo s/n Villanueva de la Cañada Madrid28692 Spain Aix Marseille Univ CNRS CNES LAM Marseille France Université Paris-Saclay CEA IRFU Gif-sur-Yvette91191 France INAF - Osservatorio Astrofisico di Arcetri Largo E. Fermi 5 Firenze50125 Italy School of Physics & Astronomy Space Park Leicester University of Leicester 92 Corporation Road LeicesterLE4 5SP United Kingdom Department of Astronomy Stockholm University AlbaNova University Center Stockholm10691 Sweden UK Astronomy Technology Centre Royal Observatory Blackford Hill EdinburghEH9 3HJ United Kingdom Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Dr. PasadenaCA91109 United States Université Paris-Saclay UVSQ CNRS CEA Maison de la Simulation Gif-sur-Yvette91191 France Department of Astrophysics American Museum of Natural History New YorkNY1

Context. The newly accessible mid-infrared (MIR) window offered by the James Webb space Telescope (JWST) for exoplanet imaging is expected to provide valuable information to characterize their atmospheres. In particular, coronagraphs on board the JWST Mid-InfraRed instrument (MIRI) are capable of imaging the coldest directly imaged giant planets at the wavelengths where they emit most of their flux. The MIRI coronagraphs have been specially designed to detect the NH3 absorption around 10.5 µm, which has been predicted by atmospheric models and should be detectable for planets colder than 1200 K. Aims. We aim to assess the presence of NH3 while refining the atmospheric parameters of one of the coldest companions detected by directly imaging GJ 504 b. Its mass is still a matter of debate and depending on the host star age estimate, the companion could either be placed in the brown dwarf regime of ∼ 20 MJup or in the young Jovian planet regime of ∼ 4 MJup. Methods. We present an analysis of new MIRI observations, using the coronagraphic filters F1065C, F1140C, and F1550C of the GJ 504 system. We took advantage of previous observations of reference stars to build a library of images and to perform a more efficient subtraction of the stellar diffraction pattern. We used an atmospheric grid from the Exo-REM model to refine the atmospheric parameters by combining archival near-infrared (NIR) photometry with the MIR photometry. Results. We detected the presence of NH3 at 12.5 σ and measured its volume mixing ratio of 10−5.3±0.07 in the atmosphere of GJ 504 b. These results are in line with atmospheric model expectations for a planetary-mass object and observed in brown dwarfs within a similar temperature range. The best-fit model with Exo-REM provides updated values of its atmospheric parameters, yielding a temperature of Teff = 512±10 K and radius of R = 1.08+−00.0403 RJup. Conclusions. These observations demonstrate the capability of MIRI coronagraphs to detect NH3 and to

关键词： space telescopes

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On the stability of nonlinear time-varying spacecraft control systems 68

On the stability of nonlinear time-varying spacecraft contro...

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68th International Astronautical Congress: Unlocking Imagination, Fostering Innovation and Strengthening Security, IAC 2017

作者： Xie, Yongchun Chen, Zhihua Science and Technology on Space Intelligent Control Laboratory Beijing Institute of Control Engineering Beijing100094 China Tianjin Key Laboratory of Microgravity and Hypogravity Environment Simulation Technology Tianjin330452 China

ISBN: (纸本)9781510855373

Stability is crucial for spacecraft control system. For rigid-body satellites or rigid-body satellites with flexible appendages, the closed-loop control systems are linear time-invariant (LTI) systems when linear controller, such as PID controllers are used. The stability of such kind of systems is usually analyzed by the Nyquist criterion. And the gain margin and phase margin of the control systems can be obtained. But for spacecraft with the consumption of liquid propellants, the Nyquist method is no longer suitable for stability analysis, especially when nonlinear controllers are used. Though Lyapunov stability analysis method can be used for time-varying linear or nonlinear systems, it cannot provide the stability margin that is widely used in engineering, thus limiting its practical applications. In order to solve this problem, a new framework for stability analysis of nonlinear time-varying systems based on computer simulation, which is suitable for engineering applications, is discussed in this paper. And some preliminary theoretical results are introduced. © 2017 International Astronautical Federation IAF. All rights reserved.

关键词： Closed loop control systems

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