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Engineering 2021年第7期7卷 26-33页

作者：潘雄飞杨娟温莹李乃适陈思邈潘安 Department of Epidemiology and Biostatistics School of Public Health Tongji Medical College Huazhong University of Science and Technology Division of Epidemiology Department of Medicine Vanderbilt University Medical Center The George Institute for Global Health University of New South Wales Ministry of Education Key Laboratory of Public Health Safety School of Public Health Fudan University Department of Communicable Diseases Control and Prevention Shenzhen Center for Disease Control and Prevention National Health Commission Key Laboratory of Endocrinology Department of Endocrinology Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Heidelberg Institute of Global Health Heidelberg Medical School Heidelberg University Chinese Academy of Medical Sciences and Peking Union Medical College

1.引言严重急性呼吸综合征冠状病毒2(SARS-Co V-2)引起的新冠病毒肺炎(COVID-19)已成为流行病,并席卷全球[1]。截至2021年4月1日,全球约有1.295亿新冠病毒肺炎确诊病例和280万新冠病毒肺炎死亡病例[2]。虽然部分国家的新冠病毒肺炎疫情...

1.引言严重急性呼吸综合征冠状病毒2(SARS-Co V-2)引起的新冠病毒肺炎(COVID-19)已成为流行病,并席卷全球[1]。截至2021年4月1日,全球约有1.295亿新冠病毒肺炎确诊病例和280万新冠病毒肺炎死亡病例[2]。虽然部分国家的新冠病毒肺炎疫情得到控制,但世界上大多数国家的政府部门仍在调动可用资源以遏制新型冠状病毒的社区传播,改善医院内新冠病毒肺炎治疗,

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Quadratic contact point semimetal: Theory and material realization

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Physical Review B 2018年第12期98卷 125104-125104页

作者： Ziming Zhu Ying Liu Zhi-Ming Yu Shan-Shan Wang Y. X. Zhao Yuanping Feng Xian-Lei Sheng Shengyuan A. Yang Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore 487372 Singapore Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics and Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha 410081 China National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Nanjing 210093 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093 China Department of Physics National University of Singapore Singapore 117542 Singapore Department of Physics Key Laboratory of Micro-nano Measurement-Manipulation and Physics (Ministry of Education) Beihang University Beijing 100191 China Center for Quantum Transport and Thermal Energy Science School of Physics and Technology Nanjing Normal University Nanjing 210023 China

Most electronic properties of metals are determined solely by the low-energy states around the Fermi level and, for topological metals/semimetals, these low-energy states become distinct because of their unusual energy dispersion and emergent pseudospin degree of freedom. Here, we propose a class of materials which are termed as quadratic contact point (QCP) semimetals. In these materials, the conduction and valence bands contact at isolated points in the Brillouin zone, around which the band dispersions are quadratic along all three directions. We show that in the absence/presence of spin-orbit coupling, there may exist triply/quadruply degenerate QCPs that are protected by the crystalline symmetry. We construct effective models to characterize the low-energy fermions near these QCPs. Under strong magnetic field, unlike the usual 3D electron gas, there appear unconventional features in the Landau spectrum. The QCP semimetal phase is adjacent to a variety of topological phases. For example, by breaking symmetries via Zeeman field or lattice strain, it can be transformed into a Weyl semimetal with Weyl and double Weyl points, a Z2 topological insulator/metal, or a Dirac semimetal. Via first-principles calculations, we identify realistic materials Cu2Se and RhAs3 as candidates for QCP semimetals.

关键词： First-principles calculations Topological materials 3-dimensional systems Density functional theory Wannier function methods k dot p method

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Field-Driven Quantum Criticality in the Spinel Magnet ZnCr2Se4

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Physical Review Letters 2018年第14期120卷 147204-147204页

作者： C. C. Gu Z. Y. Zhao X. L. Chen M. Lee E. S. Choi Y. Y. Han L. S. Ling L. Pi Y. H. Zhang G. Chen Z. R. Yang H. D. Zhou X. F. Sun Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory Chinese Academy of Sciences Hefei Anhui 230031 People’s Republic of China Department of Physics Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics (CAS) University of Science and Technology of China Hefei Anhui 230026 People’s Republic of China Fujian Institute of Research on the Structure of Matter Chinese Academy of Sciences Fuzhou Fujian 350002 People’s Republic of China National High Magnetic Field Laboratory Florida State University Tallahassee Florida 32306-4005 USA Department of Physics Florida State University Tallahassee Florida 32306-3016 USA Collaborative Innovation Center of Advanced Microstructures Nanjing Jiangsu 210093 People’s Republic of China State Key Laboratory of Surface Physics and Department of Physics Center for Field Theory and Particle Physics Fudan University Shanghai 200433 China Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 People’s Republic of China Key laboratory of Artificial Structures and Quantum Control (Ministry of Education) School of Physics and Astronomy Shanghai JiaoTong University Shanghai 200240 China Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996-1200 USA

We report detailed dc and ac magnetic susceptibilities, specific heat, and thermal conductivity measurements on the frustrated magnet ZnCr2Se4. At low temperatures, with an increasing magnetic field, this spinel material goes through a series of spin state transitions from the helix spin state to the spiral spin state and then to the fully polarized state. Our results indicate a direct quantum phase transition from the spiral spin state to the fully polarized state. As the system approaches the quantum criticality, we find strong quantum fluctuations of the spins with behaviors such as an unconventional T2-dependent specific heat and temperature-independent mean free path for the thermal transport. We complete the full phase diagram of ZnCr2Se4 under the external magnetic field and propose the possibility of frustrated quantum criticality with extended densities of critical modes to account for the unusual low-energy excitations in the vicinity of the criticality. Our results reveal that ZnCr2Se4 is a rare example of a 3D magnet exhibiting a field-driven quantum criticality with unconventional properties.

关键词： Frustrated magnetism Magnetism

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Analysis and evaluation of heavy metal pollution in agricultural soils in six cities of Hunan Province, China

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IOP Conference Series: Earth and Environmental science 2019年第1期349卷

作者： Yang Yu Cong Sun Linlin Zhang Renji Xu Yuanyuan Zhu Guoping Wu Fusheng Wei Anhui Institute of Optics and Fine Mechanics Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei 230026 China University of Science and Technology of China Hefei 230026 China State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring China National Environmental Monitoring Center Beijing 100012 P.R.China

Environmental problems caused by the exploitation of mineral resources are worsening, especially the heavy metal pollution in soil. Food safety caused by heavy metal pollution in soil has become the focus of increasing *** points were selected in Hunan Province. By sampling the soil and rice point by point, the total concentration and the concontration in rice were monitored. The results showed that the mean concentration of Cd, Cu, Hg, Pb and Zn were 1.31 mg/kg, 45.3 mg/kg, 0.61 mg/kg, 49.15 mg/kg and 133.3 mg/kg. The soils were contaminated in some parts of the 85 investigated sites in Hunan ***, the analysis results showed that the average of PI (pollution index) descended in the order of Cd (2.58) > Hg (1.05) > Cu (0.52)> Zn (0.51)> Pb (0.41).The NIPI values of the research area were 28.59, belong to the high-level pollution, which mainly caused by Cd. The pollution ratio of soil samples were 100.0% in Zhuzhou-Xiangtan and Changning, 94.1%, 90.9% and 88.2% in Changde, Yiyang and Yongzhou. According to the potential ecological risk evaluation result, there was a medium level risk in the investigation area of Hunan and the potential ecological risk mainly caused by Cd.

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Realization of broadband reflective polarization converter using asymmetric cross-shaped resonator

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Optical Materials Express 2016年第4期6卷 1393-1404页

作者： Zhang, Linbo Zhou, Peiheng Lu, Haipeng Zhang, Li Xie, Jianliang Deng, Longjiang National Engineering Research Center of Electromagnetic Radiation Control Materials State Key Laboratory of Electronic Thin Film and Integrated Devices University of Electronic Science and Technology of China Chengdu Sichuan610054 China

Cross-shaped resonator (CSR) in metamaterial usually corresponds to adjust resonant characteristics. In this report, a simple and broadband reflective polarization converter is realized at GHz frequencies by breaking the symmetry of the CSR. The experimental results demonstrate that the polarization conversion ratio (PCR) over 0.8 is achieved from 8.3 GHz to 14.3 GHz for linearly polarized (LP) incident waves under normal incidence. The high polarization conversion efficiency can be sustained when the incident angle increases to 60 degrees. By taking advantage of surface current distribution and the interference theory, the physical mechanisms are elucidated in detail. Finally, the broadband polarization conversion can also be achieved by decreasing the geometrical parameters of the converter in the mid-infrared frequency range. © 2016 Optical Society of America.

关键词： Resonators

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A Thin Magnetic-Type Absorber for Wide Incidence Angles and Both Polarizations Using Dipole-Arrays

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IOP Conference Series: Materials science and Engineering 2018年第1期381卷

作者： Shuai Wang Cailin Ye Linbo Zhang Haiyan Xie Difei Liang Jianliang Xie State Key Laboratory of Electronic Thin Film and Integrated Devices National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of China Chengdu 610054 China

A thin microwave radar absorber with metallic dipole arrays incorporated into magnetic polymer composite is proposed to operate over a wide range of incidence angles for both TE and TM polarizations. Owing to the impedance characteristics, the magnetic absorber (MA) without dipoles cannot hold oblique-incidence-absorption for TM polarization. By introducing dipoles, the incorporated MA exhibits a broad bandwidth for reflection equal or less than -10 dB for incidence angle up to 60° for TM polarization, and remains excellent oblique-incidence absorption for TE polarization. The improvement of oblique-incidence absorption for TM polarization is related to LC resonance caused by the embedded dipoles. The experimental results show that the proposed MA with a thickness of 2.0mm provides wide bandwidth (5.0 GHz ~15.7 GHz for normal incidence and 4.5 GHz ~14.8 GHz for incidence angle of 45°) for TM polarization, which is agreement with the simulated results.

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Author Correction: Arsenic mobilization by anaerobic iron-dependent methane oxidation

Communications Earth & Environment

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Communications Earth & Environment 2020年第1期1卷 1页

作者： Martyna Glodowska Andreas Kappler Daniel Straub Sara Kleindienst Emiliano Stopelli Alex Lightfoot Rolf Kipfer Michael Berg Magnus Schneider Bhasker Rathi Mike Jetten M. Glodowska A. Kappler S. Kleindienst O. A. Cirpka B. Rathi A. Lightfoot E. Stopelli M. Berg R. Kipfer L. Winkel T. Neumann Pham Hung Viet Trang Pham D. Vu Vi Mai Lan Mai Tran Viet Nga H. Prommer Geomicrobiology Center for Applied Geosciences University of Tubingen 72074 Tübingen Germany Microbial Ecology Center for Applied Geosciences University of Tübingen 72074 Tübingen Germany Quantitative Biology Center (QBiC) University of Tübingen 72074 Tübingen Germany Eawag Swiss Federal Institute of Aquatic Science and Technology 8600 Dübendorf Switzerland Institute of Geochemistry and Petrology Swiss Federal Institute of Technology and Technology ETHZ 8092 Zurich Switzerland Division of Aquatic Geochemistry Institute of Applied Geosciences Karlsruhe Institute of Technology (KIT) 76131 Karlsruhe Germany Hydrogeology Center for Applied Geosciences University of Tübingen 72074 Tübingen Germany CSIRO Land and Water WA 6014 Floreat Australia Institute for Water and Wetland Research Radboud University 6525 Nijmegen The Netherlands Department of Geosciences University of Tübingen 72074 Tübingen Germany Department of Water Resources and Drinking Water Eawag Swiss Federal Institute of Aquatic Science and Technology 8600 Dübendorf Switzerland Technische Universität Berlin 10623 Berlin Germany Vietnam National University of Science Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS) Hanoi 1000 Vietnam The University of Western Australia Perth WA 6009 Australia

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Author Correction: Near-real-time monitoring of global CO2 emissions reveals the effects of the COVID-19 pandemic

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Nature communications 2020年第1期11卷 6292页

作者： Zhu Liu Philippe Ciais Zhu Deng Ruixue Lei Steven J Davis Sha Feng Bo Zheng Duo Cui Xinyu Dou Biqing Zhu Rui Guo Piyu Ke Taochun Sun Chenxi Lu Pan He Yuan Wang Xu Yue Yilong Wang Yadong Lei Hao Zhou Zhaonan Cai Yuhui Wu Runtao Guo Tingxuan Han Jinjun Xue Olivier Boucher Eulalie Boucher Frédéric Chevallier Katsumasa Tanaka Yiming Wei Haiwang Zhong Chongqing Kang Ning Zhang Bin Chen Fengming Xi Miaomiao Liu François-Marie Bréon Yonglong Lu Qiang Zhang Dabo Guan Peng Gong Daniel M Kammen Kebin He Hans Joachim Schellnhuber Department of Earth System Science Tsinghua University Beijing China. zhuliu@***. Laboratoire des Sciences du Climat et de l'Environnement LSCE CEA CNRS UVSQ Centre d'Etudes Orme de Merisiers Gif-sur-Yvette France. Department of Earth System Science Tsinghua University Beijing China. Department of Meteorology and Atmospheric Science The Pennsylvania State University University Park PA USA. Department of Earth System Science University of California Irvine 3232Croul Hall Irvine CA USA. Division of Geological and Planetary Sciences California Institute of Technology Pasadena CA USA. Jet Propulsion Laboratory California Institute of Technology Pasadena CA USA. Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science and Technology Nanjing China. Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China. Climate Change Research Center Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China. School of Environment Tsinghua University Beijing China. School of Mathematical School Tsinghua University Beijing China. Department of Mathematical Sciences Tsinghua University Beijing China. Center of Hubei Cooperative Innovation for Emissions Trading System Wuhan China. Faculty of Management and Economics Kunming University of Science and Technology 13 Kunming China. Economic Research Centre of Nagoya University Furo-cho Chikusa-ku Nagoya Japan. Institut Pierre-Simon Laplace Sorbonne Université/CNRS Paris France. Université Paris Dauphine Place du Maréchal de Lattre de Tassigny 75016 Paris France.

A Correction to this paper has been published: https://***/10.1038/s41467-020-20254-5.

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Tunable Quantum Spin Liquidity in the 1/6th-Filled Breathing Kagome Lattice

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Physical Review Letters 2018年第22期120卷 227201-227201页

作者： A. Akbari-Sharbaf R. Sinclair A. Verrier D. Ziat H. D. Zhou X. F. Sun J. A. Quilliam Institut Quantique and Département de Physique Université de Sherbrooke 2500 boulevard de l’Université Sherbrooke Québec J1K 2R1 Canada Department of Physics and Astronomy University of Tennessee Knoxville Tennessee 37996-1200 USA Key Laboratory of Artificial Structures and Quantum Control Ministry of Education School of Physics and Astronomy Shanghai JiaoTong University Shanghai 200240 China Department of Physics Hefei National Laboratory for Physical Sciences at Microscale and Key Laboratory of Strongly-Coupled Quantum Matter Physics CAS University of Science and Technology of China Hefei Anhui 230026 People’s Republic of China Institute of Physical Science and Information Technology Anhui University Hefei Anhui 230601 People’s Republic of China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing Jiangsu 210093 People’s Republic of China

We present measurements on a series of materials, Li2In1−xScxMo3O8, that can be described as a 1/6th-filled breathing kagome lattice. Substituting Sc for In generates chemical pressure which alters the breathing parameter nonmonotonically. Muon spin rotation experiments show that this chemical pressure tunes the system from antiferromagnetic long range order to a quantum spin liquid phase. A strong correlation with the breathing parameter implies that it is the dominant parameter controlling the level of magnetic frustration, with increased kagome symmetry generating the quantum spin liquid phase. Magnetic susceptibility measurements suggest that this is related to distinct types of charge order induced by changes in lattice symmetry, in line with the theory of Chen et al. [Phys. Rev. B 93, 245134 (2016)]. The specific heat for samples at intermediate Sc concentration, which have the minimum breathing parameter, show consistency with the predicted U(1) quantum spin liquid.

关键词： Antiferromagnetism Frustrated magnetism Magnetic phase transitions Magnetic susceptibility Quantum spin liquid Kagome lattice DC susceptibility measurements Muon spin resonance Specific heat measurements X-ray powder diffraction

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Influence of foraminifera on formation and occurrence characteristics of natural gas hydrates in fine-grained sediments from Shenhu area, South China Sea

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science China Earth sciences 2016年第11期59卷 2223-2230页

作者： LI ChengFeng HU GaoWei ZHANG Wei YE YuGuang LIU ChangLing LI Qing SUN JianYe Key Laboratory of Gas Hydrate Ministry of Land and Resources Qingdao Institute of Marine Geology Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and Technology College of Information and Control Engineering China University of Petroleum

Marine gas hydrates accumulate primarily in coarse-grained, high-permeability layers; however, highly saturated natural gas hydrates have been discovered in the fine-grained sediments of Shenhu area, South China Sea(SCS). This may be explained by key factors, such as the great abundance of foraminifera shells. In this paper, by analyzing the SCS foraminifera structure and performing hydrate formation experiments in the foraminifera shells, the contribution of foraminifera to hydrate accumulation in the SCS was investigated from a microscopic point of view. Simulations of hydrate formation were carried out in both pure SCS foraminifera shells and the host sediments. Pore structures in typical foraminifera were studied by use of micro-focus X-ray computed tomography(CT) and scanning electron microscopy(SEM). Hydrate growth and occurrence characteristics in the foraminifera shells were observed in-situ. The results showed that the presence of foraminifera significantly enhanced the effective porosity of the SCS sediments. Moreover, while the hydrates grew preferentially in the chambers of the coarse-grained foraminifera by adhering to the inner walls of the foraminifera shells, no apparent hydrate accumulation was observed in the fine-grained or argillaceous matrix. These findings provide a basis for further studies on the accumulation mechanism of hydrates and physical properties of hydrate reservoir in the South China Sea.

关键词： Shenhu area Foraminifera Gas hydrate Occurrence characteristics X-ray computed tomography

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