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Structural And Electronic Properties Of Weyl Semimetal Wte2 Under High Pressure

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SSRN 2023年

作者： Li, Yuqiang Li, Yuhong Zhang, Qiang Liu, Xiaofeng Xiao, Ningru Ning, Pingfan Wang, Jingjing Liu, Yang Zhang, Jianxin Liu, Hongwei Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems School of Electronic and Information Engineering Tiangong University Tianjin300387 China Key Laboratory of Smart Grid Ministry of Education School of Electrical and Information Engineering Tianjin University Tianjin300072 China Tianjin San’an Optoelectronics Co. Ltd. Tianjin300384 China Engineering Research Center of High Power Solid State Lighting Application System Ministry of Education Tiangong University Tianjin300387 China School of Physical Science and Technology Tiangong University Tianjin300387 China

The structural and electronic properties of WTe2 are studied from ambient pressure to 30.0 GPa. The pressure-induced structural phase transition is found from Td phase (Pnm21, No. 31) to 1T′ phase (P21/m, No. 11) above 10.0 GPa by lattice offset, which is also reflected at approximately 11.2 GPa based on the discontinuous electrical parameters. A pair of hole wave and electron wave packets of Td phase gradually overlap revealing the reversible Td-to-1T′ phase structural transition. WTe2 is observed to undergo semimetal-to-semiconductor transition owing to the calculated energy band up to 15 GPa, which is also observed at 11.2 GPa according to the resistivity-temperature curves under compression and decompression conditions. The electronic density of states at the Fermi level is mainly contributed by the d orbital of W and the p and s orbital of Te. The photoconductivity property is shown by the theoretical and experimental methods. © 2023, The Authors. All rights reserved.

关键词： Electronic properties

Issues,Progress,and Recommendations in the Construction of Ecological Barrier on the Mongolian Plateau from the Perspective of Big Data

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Journal of Resources and Ecology 2024年第5期15卷 1113-1124页

作者： WANG Juanle LI Kai XU Shuxing SHAO Yating WANG Meng LI Menghan ZHANG Yu LIU Yaping LI Fengjiao Ochir ALTANSUKH Chuluun TOGTOKH State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChineseAcademy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China College of Geoscience and Surveying Engineering China University of Mining&Technology(Beijing)Beijing 100083China College of Geomatics Xi’an University of Science and TechnologyXi’an 710054China Environmental Engineering Laboratory Department of Environment and Forest EngineeringNational University of MongoliaUlaanbaatar 14201Mongolia Institute for Sustainable Development National University of MongoliaUlaanbaatar 14201Mongolia

The Mongolian Plateau(MP),situated in the transitional zone between the Siberian taiga and the arid grasslands of Central Asia,plays a significant role as an Ecological Barrier(EB)with crucial implications for ecological and resource security in Northeast *** is a vast concept and a complex issue related to many aspects such as water,land,air,vegetation,animals,and people,et *** is very difficult to understand the whole of EB without a comprehensive perspective,that traditional diverse studies cannot *** data and artificial intelligence(AI)have enabled a shift in the research *** with these requirements,this study identified issues in the construction of EB on MP from a big data *** includes the issues,progress,and future recommendations for EB construction-related studies using big data and *** issues cover the status of theoretical studies,technical bottlenecks,and insufficient synergistic analyses related to EB *** progress introduces advances in scientific research driven by big data in three key areas of MP:natural resources,the ecological environment,and sustainable *** the future development of EB construction on MP,it is recommended to utilize big data and intelligent computing technologies,integrate extensive regional data resources,develop precise algorithms and automated tools,and construct a big data collaborative innovation plat*** study aims to call for more attention to big data and AI applications in EB studies,thereby supporting the achievement of sustainable development goals in the MP and enhancing the research paradigm transforming in the fields of resources and the environment.

关键词： Mongolian Plateau resources and ecology big data artificial intelligence research paradigm

First-Principles Study of Electronic Structure and Metallization of Mg2pb Under High Pressure

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SSRN 2023年

作者： Li, Yuqiang Li, Yuhong Zhang, Qiang Su, Ningning Sun, Jinlu Xiao, Ningru Liu, Yang Liu, Yuyao Ning, Pingfan Liu, Hongwei Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems School of Electronics and Information Engineering Tiangong University Tianjin300387 China Key Laboratory of Smart Grid of Ministry of Education School of Electrical and Information Engineering Tianjin University Tianjin300072 China School of Semiconductor and Physics North University of China Taiyuan030051 China Engineering Research Center of High Power Solid State Lighting Application System Ministry of Education Tiangong University Tianjin300387 China School of Physical Science and Technology Tiangong University Tianjin300387 China

The high-pressure electronic structure and electrical properties of Mg2Pb are investigated from ambient pressure to 42 GPa by first-principles calculation. Mg2Pb undergoes reversible structural transitions from Fm-3m structure to Pnma structure and then to P63/mmc structure. The structural phase transitions are determined respectively at around 6 GPa and 28 GPa using pressure-dependent enthalpy calculations, which are also reflected from the cell volume collapse and discontinuous axial ratios of lattice constants. The sliding of Mg and Pb atomic layers is revealed via the Mg1-Pb-Mg2 atom pair during structural phase transitions, corresponding to abrupt decrease of c/b and a/b. The semimetal-to-metal transition is also observed at approximately 28 GPa owing to energy-band closure, whilst metallic character is strengthened with increasing pressure. The paper is prone to explore the structural phase transition and metallization of Mg2Pb-type family in theory under extreme conditions. © 2023, The Authors. All rights reserved.

关键词： Electronic structure

First-Principles Study of Electronic Structure and Metallization of Xpse3 (X=Fe, Mn) Under High Pressure

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SSRN 2023年

作者： Li, Yuqiang Li, Yuhong Zhang, Qiang Su, Ningning Sun, Jinlu Xiao, Ningru Liu, Yang Liu, Yuyao Zhang, Jianxin Liu, Hongwei Tianjin Key Laboratory of Optoelectronic Detection Technology and Systems School of Electronics and Information Engineering Tiangong University Tianjin300387 China Key Laboratory of Smart Grid of Ministry of Education School of Electrical and Information Engineering Tianjin University Tianjin300072 China School of Semiconductor and Physics North University of China Taiyuan030051 China Engineering Research Center of High Power Solid State Lighting Application System of Ministry of Education Tiangong University Tianjin300387 China School of Physical Science and Technology Tiangong University Tianjin300387 China

The pressure-induced structural phase transition and metallization of FePSe3 and MnPSe3 are investigated from ambient pressure to 40 GPa by first-principles calculation. FePSe3 and MnPSe3 undergo reversible structural transitions from R-3 structure to C2/m structure and then to P-31m structure. The structural phase transitions of FePSe3 are at about 6 GPa and 13 GPa, while the pressure points are at approximately 13 GPa and 25 GPa for MnPSe3, reflecting from pressure-dependent enthalpy calculation, cell volume collapses, and sudden changes of lattice parameters. The computed metallization transition is also observed at around 8 GPa and 16 GPa owing to energy-band closure for FePSe3 and MnPSe3, respectively. The metallic character of XPSe3 is strengthened with increasing pressure based on the electronic energy band and electron density of states. The layer sliding of atoms is revealed using the P2-P3 atom pair of XPSe3 during structural phase transitions. The paper is conducive to considering the electronic structure and metallization of transition metal thiophosphates XPSe3-type family under extreme conditions. © 2023, The Authors. All rights reserved.

关键词： Electronic structure

Efficient Sparse MIMO SAR Imaging with Fast Iterative Method Based on Back Projection and Approximated Observation

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Efficient Sparse MIMO SAR Imaging with Fast Iterative Method...

Electronics and Electrical Engineering technology (EEET), International Conference on

作者： Pengyu Jiang Zhe Zhang Bingchen Zhang Key Laboratory of Technology in Geo-Spatial Information Processing and Application System Chinese Academy of Sciences Beijing China Aerospace Information Research Institute Chinese Academy of Sciences Beijing China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Beijing China Suzhou Aerospace Information Research Institute Suzhou China

Compressed sensing technique is widely used in the field of multiple input multiple output (MIMO) radar imaging to suppress sidelobes and noise, bringing better imaging performance. However, many constraints are introduced to the sparse reconstruction model, current sparse microwave imaging model is based on several assumptions, such as far field assumption, which might not hold in some circumstances. In this paper, a novel two-dimensional sparse reconstruction method based on approximated observation is proposed. First, we obtain the measurement matrix by the inverse back-projection operator, and construct a two-dimensional sparse reconstruction model. Then, we adopt the minimax concave constraint as the regularization term and use the iterative soft threshold algorithm (ISTA) for sparse reconstruction. The method retains the advantages of the BP algorithm and the sparse reconstruction algorithm at the same time, and the distance between the target and the antenna array is not constrained by image reconstruction performance of the sparse reconstruction algorithm. Simulations and experiments demonstrate the effectiveness of the proposed method.

关键词： MIMO radar Simulation Imaging Radar imaging Reconstruction algorithms Sparse matrices Velocity measurement

Preliminary Analysis of PolInSAR Scattering Mechanism in Urban Areas through UAV-borne PolInSAR system

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Preliminary Analysis of PolInSAR Scattering Mechanism in Urb...

IEEE International Conference on Radar

作者： Zexin Lv Xiaolan Qiu Chibiao Ding Key Laboratory of Technology in Geo-spatial Information Processing and Application System Beijing China Aerospace Information Research Institute (of Chinese Academy of Sciences) Beijing China University of Chinese Academy of Sciences Beijing China Key Laboratory of Intelligent Aerospace Big Dara Application Technology Suzhou China Suzhou Aerospace Information Research Institute Suzhou China

ISBN: (纸本)9781665468893

Polarimetric Interferometric SAR (PolInSAR) can improve the coherence of images and it plays an important role in urban remote sensing. The explanation of its scattering mechanism is concerned by many researchers. It is always explained from the aspect of different polarization decompositions but seldom from the height of scattering centers. In this paper, a Ku-band UAV-borne PolInSAR system is used to compare the relationship of scattering centers between PolInSAR and Pauli decomposition on different artificial targets. The physical meaning of PolInSAR is preliminary analyzed and our conclusion is also verified through a C-band manned airborne PolInSAR system.

关键词： C-band Airborne radar Urban areas Scattering Coherence Radar polarimetry Synthetic aperture radar

Seamless maps of major elements of the Moon:Results from high-resolution geostationary satellite

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Research in Astronomy and Astrophysics 2021年第2期21卷 52-60页

作者： Yu Lu Yun-Zhao Wu Cui Li Jin-Song Ma Wen-Wen Qi Wei Tan Xiao-Man Li Zhi-Cheng Shi Hong-Yan He Shu-Wu Dai Guo Li Feng-Jing Liu Jing-Qiao Wang Xiao-Yan Wang Qi Wang Ling-Jie Meng Key Laboratory of Planetary Sciences Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210034China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Hefei 230026China Space Science Institute Macao University of Science and TechnologyMacaoChina School of Geography and Ocean Science Nanjing UniversityNanjing 210023China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023China Beijing Institute of Space Mechanics and Electricity Beijing 100076China Beijing Institute of Spacecraft System Engineering Beijing 100076China China Centre for Resources Satellite Data and Application Beijing 100094China Earth Observation System and Data Center China National Space AdministrationBeijing 100010China

Major elements such as Fe,Ti,Mg,Al,Ca and Si play very important roles in understanding the origin and evolution of the *** maps of these major elements derived from orbital data are based on mosaic images or low-resolution gamma-ray *** hue variations and gaps among orbital boundaries in the mosaic images are not conducive to geological *** paper aims to produce seamless and homogenous distribution maps of major elements using the single-exposure image of the whole lunar disk obtained by China’s high-resolution geostationary satellite,Gaofen-4,with a spatial resolution of500 *** elemental contents of soil samples returned by Apollo and Luna missions are regarded as ground truth,and are correlated with the reflectance of the sampling sites extracted from Gaofen-4 *** final distribution maps of these major oxides are generated with the statistical regression *** these products,the average contents and proportions of the major elements for maria and highlands were estimated and *** results showed that Si O2 and Ti O2 have the highest and lowest fractions in mare and highland areas,***,the relative concentrations of these elements could serve as indicators of geologic processes,e.g.,the obviously asymmetric distributions of Al2 O3,Ca O and Si O2 around Tycho crater may suggest that Tycho crater was formed by an oblique impact from the southwest direction.

关键词： Moon-Data analysis-Imaging spectroscopy

Research on Spatiotemporal Evolution Law of Black and Odorous Water Body in Guangzhou City 7th

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Research on Spatiotemporal Evolution Law of Black and Odorou...

7th International Conference on Geoinformatics in Sustainable Ecosystem and Society, GSES 2019, and 1st International Conference on geospatial Artificial Intelligence for Urban Computing, GeoAI 2019

作者： Zhao, Qian Han, Liusheng Li, Yong Yang, Ji Wang, Shuxiang Zhu, Congjun Li, Yinguo Shandong University of Technology Zibo255000 China Guangdong Key Laboratory of Geospatial Information Technology and Application Guangzhou Institute of Geography Guangzhou510070 China State Grid Chongqing Yongchuan Power Supply Company YongchuanChongqing402106 China

ISBN: (纸本)9789811561054

The urban black and odorous water bodies affect the daily life of urban residents, destroy the aquatic ecosystem and damage the image of the city. This research used the evaluation method of black and odorous water body proposed by the Ministry of Housing and Urban-Rural Development of the People’s Republic of China (MOHURD) to evaluate the water quality of 50 key creeks (53 sections) in Guangzhou in 2016 and 2017 and analyzed the spatial distribution of black and odorous water bodies and their changes over time. The results showed that the water quality of Conghua District, Panyu District, Nansha District, and Yuexiu District was relatively good, while the water quality of Baiyun District, Haizhu District, Huadu District, Huangpu District, Liwan District, Tianhe District, and Zengcheng District was relatively poor. Compared with 2016, the water quality of creeks in Huangpu District and Baiyun District deteriorated in 2017, while the water quality of creeks in Tianhe District, Liwan District, and Huadu District improved. The water quality of creeks in other districts did not change significantly. In 2017, ammonia nitrogen (NH3-N), total phosphorus (TP), and chemical oxygen demand (COD) content decreased, and dissolved oxygen (DO) content increased compared to 2016. In 2017, the number of black-odor water bodies was greatly reduced, and the water quality of creeks was generally improved. The results can provide a reference for the treatment of the black and odorous creeks in Guangzhou. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Water quality

Understanding the Long-Distance Travel Mobility of Passengers Based on Big Railway Data: Travel Network and Motif Perspectives

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SSRN 2022年

作者： Xu, Jin Song, Haonan Lu, Zhaoyang Department of Information System & Operation Management School of Economics and Management Southwest Jiaotong University Sichuan Chengdu China National Engineering Laboratory of Integrated Transportation Big Data Application Technology Sichuan Chengdu China Service Science and Innovation Key Laboratory of Sichuan Province Sichuan Chengdu China

With the booming construction of new railway lines and stations in China, the number of railway passengers is increasing. The large railway population shows certain mobility characteristics that we are interested in clarifying. Based on the theory of complex networks, this paper proposes a novel method to identify travel patterns from big railway data, which associates travel motifs with travel networks. This paper derives some meaningful results from the data analysis of more than three million railway travel records of a city in China. These results illustrate that higher motif complexity leads to a narrower travel radius for motif-based subnets. The higher the stability of the travel sequence is, the shorter the average length of the sequence. Four types of travel patterns are identified and classified by analyzing the motif of travel activities, i.e., labor, tourism, surrounding and commuting. The methodology and findings presented in this paper contribute to a better understanding of the long-distance travel mobility of railway passengers. The method designed in this paper can also be used to analyze traffic data from airlines, buses, subways, etc. © 2022, The Authors. All rights reserved.

关键词： Complex networks