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Drivers,Trends,and Patterns of Changing Vegetation-greenness in Nansha Islands,China from 2016 to 2022

Chinese geographical Science 2024年第4期34卷 662-673页

作者： TANG Jiasheng FU Dongjie SU Fenzhen YU Hao WANG Xinhui Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China State Key Laboratory of Resources and Environmental information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Collaborative Innovation Center of South China Sea Studies Nanjing 210023China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China Beijing North-Star Technology Development Co. LtdBeijing 100120China

Changes in vegetation status generally also represents changes in the ecological health of islands and reefs(IRs).However,studies are limited of drivers and trends of vegetation change of Nansha Islands,China and how they relate to climate change and human *** resolve this limitation,we studied changes to the Normalized Difference Vegetation Index(NDVI)vegetation-greenness index for 22 IRs of Nansha Islands during normal and extreme *** of vegetation greenness were analyzed using Sen's slope and Mann-Kendall test at two spatial scales(pixel and island),and driving factor analyses were performed by time-lagged partial correlation *** were related to impacts from human activities and climatic factors under normal(temperature,precipitation,radiation,and Normalized Difference Built-up Index(NDBI))and extreme conditions(wind speed and latitude of IRs)from 2016 to *** showed:1)among the 22 IRs,NDVI increased/decreased significantly in 15/4 IRs,*** Reef had the highest NDVI change-rate(0.48%/mon),and Zhongye Island had the lowest(–0.29%/mon).Local spatial patterns were in one of two forms:dotted-form,and degradation in banded-form.2)Under normal conditions,human activities(characterized by NDBI)had higher impacts on vegetation-greenness than other factors.3)Under extreme conditions,wind speed(R^(2)=0.2337,P<0.05)and latitude(R^(2)=0.2769,P<0.05)provided limited explanation for changes from typhoon *** results provide scientific support for the sustainable development of Nansha Islands and the United Nations‘Ocean Decade’initiative.

关键词： island and reefs(IRs) Normalized Difference Vegetation Index(NDVI) vegetation-greenness change-rate Sen's slope Nansha Islands China

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东西伯利亚地区植被对气温和降水交互作用的定量化响应

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Journal of geographical Sciences 2024年第2期34卷 355-374页

作者：文可戈李程何剑锋庄大方 State Key Laboratory of Resources and Environment information System Institute of Geographic Sciencesand Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Nanjing Agricultural University Nanjing 210095China

Significant changes to the world’s climate over the past few decades have had an impact on the development of *** in high latitude regions,where the ecosystems are fragile,is susceptible to climate *** is possible to better understand vegetation’s phenological response to climate change by examining these *** studies have mainly investigated how a single meteorological factor affects changes in vegetation phenology through linear correlation analysis,which is insufficient for quantitatively revealing the effects of various climate factor interactions on changes in vegetation *** used the asymmetric Gaussian method to fit the normalized difference vegetation index(NDVI)curve and then used the dynamic threshold method to extract the phenological parameters,including the start of the season(SOS),end of the season(EOS),and length of the season(LOS),of the vegetation in this study area in the Tundra-Tagar transitional zone in eastern and western Siberia from 2000 to *** monthly temperature and precipitation data used in this study were obtained from the climate research unit(CRU)meteorological *** degrees to which the changes in temperature and precipitation in the various months and their interactions affected the changes in the three phenological parameters were determined using the GeoDetector,and the results were *** findings demonstrate that the EOS was more susceptible to climate change than the *** vegetation phenology shift was best explained by the climate in March,April,and September,and the combined effect of the temperature and precipitation had a greater impact on the change in the vegetation phenology compared with the effects of the individual climate *** results quantitatively show the degree of interaction between the variations in temperature and precipitation and their effects on the changes in the different phenological parameters in the various *** how

关键词： phenology climate change Siberia asymmetric Gaussian function GeoDetector

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Photoionisation detection of a single Er3+ ion with sub-100-ns time resolution

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National Science Review 2024年第4期11卷 38-45页

作者： Yangbo Zhang Wenda Fan Jiliang Yang Hao Guan Qi Zhang Xi Qin Changkui Duan Gabriele G.de Boo Brett C.Johnson Jeffrey C.Mc Callum Matthew J.Sellars Sven Rogge Chunming Yin Jiangfeng Du CAS Key Laboratory of Microscale Magnetic Resonance and School of Physical Sciences University of Science and Technology of China CAS Center for Excellence in Quantum information and Quantum Physics University of Science and Technology of China Hefei National Laboratory University of Science and Technology of China centre of Excellence for Quantum Computation and Communication Technology School of Physics University of New South Wales centre of Excellence for Quantum Computation and Communication Technology School of Engineering RMIT University centre of Excellence for Quantum Computation and Communication Technology School of Physics University of Melbourne centre of Excellence for Quantum Computation and Communication Technology Research School of Physics and Engineering Australian National University

Efficient detection of single optical centres in solids is essential for quantum information processing, sensing and single-photon generation *** this work,we use radio-frequency（RF） reflectometry to electrically detect the photoionisation induced by a single Er3+ion in *** high bandwidth and sensitivity of the RF reflectometry provide sub-100-ns time resolution for the photoionisation *** this technique,the optically excited state lifetime of a single Er3+ion in a Si nano-transistor is measured for the first time to be 0.49±0.04μ*** results demonstrate an efficient approach for detecting a charge state change induced by Er excitation and *** approach could be used for fast readout of other single optical centres in solids and is attractive for large-scale integrated optical quantum systems thanks to the multi-channel RF reflectometry demonstrated with frequency multiplexing techniques.

关键词： single optical centres erbium ions RF reflectometry photoionisation detection

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基于迁移光子雪崩效应的单束低功率激光三维多色超分辨显微成像技术

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Science Bulletin 2024年第4期69卷 458-465页

作者：朱志旻梁宇森赵琪吴蕙潘彬雄乔书倩王保举詹求强 centre for Optical and Electromagnetic Research Guangdong Engineering Research Centre of Optoelectronic Intelligent Information PerceptionSouth China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China

The development of super-resolution fluorescence microscopy is very essential for understanding the physical and biological fundamentals at nanometer ***,to date most super-resolution modalities require either complicated/costly purpose-built systems such as multiple-beam architectures or complex post-processing procedures with intrinsic *** three-dimensional(3D)or multi-channel sub-diffraction microscopic imaging using a simple method remains a challenging and struggling ***,we proposed 3D highly-nonlinear super-resolution microscopy using a singlebeam excitation strategy,and the microscopy principle was modelled and studied based on the ultrahigh nonlinearity enabled by photon *** to the simulation,the point spread function of highly nonlinear microscopy is switchable among different modes and can shrink three-dimensionally to sub-diffraction scale at the photon avalanche ***,we demonstrated 3D optical nanoscopy assisted with huge optical nonlinearities in a simple laser scanning configuration,achieving a lateral resolution down to 58 nm(λ/14)and an axial resolution down to 185 nm(λ/5)with one single beam of low-power,continuous-wave,near-infrared *** further extended the photon avalanche effect to many other emitters to develop multi-color photon avalanching nanoprobes based on migrating photon avalanche mechanism,which enables us to implement single-beam dual-color sub-diffraction super-resolution microscopic imaging.

关键词： Super-resolution microscopy Nonlinear optics Upconversion nanoparticles Photon avalanches

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Diagnosis of the Kinetic Energy of the“21·7”Extreme Torrential Rainfall Event in Henan Province,China

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Advances in Atmospheric Sciences 2024年第1期41卷 73-83页

作者： Xiuping YAO Ruoying LI Xiaohong BAO Qiaohua LIU China Meteorological Administration Training centre Beijing 100081China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China College of Atmospheric Sciences Nanjing University of Information Science and TechnologyNanjing 210044China

An extreme torrential rain(ETR)event occurred in Henan Province,China,during 18-21 July *** on hourly rain-gauge observations and ERA5 reanalysis data,the ETR was studied from the perspective of kinetic energy(K),which can be divided into rotational wind(V_(R))kinetic energy(K_(R)),divergent wind kinetic energy(K_(D)),and the kinetic energy of the interaction between the divergent and rotational winds(K_(RD)).According to the hourly precipitation intensity variability,the ETR process was divided into an initial stage,a rapid increase stage,and maintenance *** showed that the intensification and maintenance of ETR were closely related to the upper-level K,and most closely related to the upperlevel K_(R),with a correlation coefficient of up to *** particular,the peak value of hourly rainfall intensity lagged behind the K_(R) by 8 ***,diagnosis showed that K transformation from unresolvable to resolvable scales made the ETR increase *** meridional rotational wind(u_(R))and meridional gradient of the geopotential(φ)jointly determined the conversion of available potential energy(APE)to K_(R) through the barotropic process,which dominated the rapid enhancement of K_(R) and then caused the rapid increase in *** transportation of K by rotational wind consumed K_(R),and basically offset the K_(R) produced by the barotropic process,which basically kept K_(R) stable at a high value,thus maintaining the ETR.

关键词： extreme torrential rain rotational kinetic energy kinetic energy generation and transport barotropic process

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Coherent optical frequency transfer via 972-km fiber link

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Chinese Physics B 2024年第2期33卷 277-282页

作者：邓雪张翔臧琦焦东东王丹刘杰高静许冠军董瑞芳刘涛张首刚 National Time Service centre Chinese Academy of SciencesXi’an 710600China Key Laboratory of Time Reference and Application Chinese Academy of SciencesXi’an 710600China School of Communications and information Engineering and School of Artificial Intelligence Xi’an University of Posts and TelecommunicationsXi’an 710121Chin

We demonstrate coherent optical frequency dissemination over a distance of 972 km by cascading two spans where the phase noise is passively compensated *** of employing a phase discriminator and a phase locking loop in the conventional active phase control scheme,the passive phase noise cancellation is realized by feeding double-trip beat-note frequency to the driver of the acoustic optical modulator at the local *** passive scheme exhibits fine robustness and reliability,making it suitable for long-distance and noisy fiber *** optical regeneration station is used in the link for signal amplification and cascaded *** phase noise cancellation and transfer instability of the 972-km link is investigated,and transfer instability of 1.1×10^(-19)at 10^(4)s is *** work provides a promising method for realizing optical frequency distribution over thousands of kilometers by using fiber links.

关键词： optical frequency transfer fiber link phase noise cancellation

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Superconductivity in kagome metal ThRu3Si2

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Chinese Physics B 2024年第5期33卷 50-55页

作者：刘艺厉静杨武璋卢佳依曹博雅李华旬柴万力武思祺李佰卓孙云蕾焦文鹤王操许晓峰任之曹光旱 School of Physics Zhejiang University Department of Applied Physics Zhejiang University of Technology School of Science Westlake Institute for Advanced Study Westlake University Department of Physics Shandong University of Technology School of information and Electrical Engineering Zhejiang University City College Interdisciplinary Center for Quantum information and State Key Laboratory of Silicon and Advanced Semiconductor MaterialsZhejiang University Collaborative Innovation centre of Advanced Microstructures Nanjing University

We report the physical properties of ThRu3Si2featured with distorted Ru kagome lattice. The combined experiments of resistivity, magnetization and specific heat reveal bulk superconductivity with Tc= 3.8 K. The specific heat jump and calculated electron–phonon coupling indicate a moderate coupled BCS superconductor. In comparison with LaRu3Si2,the calculated electronic structure in ThRu3Si2shows an electron-doping effect with electron filling lifted from 100 meV below flat bands to 300 meV above it. This explains the lower superconducting transition temperature and weaker electron correlations observed in ThRu3Si2. Our work suggests the Tc and electronic correlations in the kagome superconductor could have an intimate connection with the flat bands.

关键词： superconductivity kagome lattice flat band

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模拟城际人口流动的量子谐振子模型

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Journal of geographical Sciences 2024年第3期34卷 459-482页

作者：胡旭钱凌欣钮潇雨高鸣罗文袁林旺俞肇元 School of Geography Nanjing Normal UniversityNanjing210023China Key Laboratory of Virtual geographic Environment Nanjing Normal UniversityMinistry of EducationNanjing210023China Jiangsu Center for Collaborative Innovation in geographical information Resource Development and Application Nanjing210023China

The simulation of intercity population mobility helps to deepen the understanding of intercity population mobility and its underlying laws,which has great importance for epidemic prevention and control,social management,and even urban *** are many factors that affect intercity population mobility,such as socioeconomic attributes,geographical distance,and industrial *** complexity of the coupling among these factors makes it difficult to simulate intercity population *** address this issue,we propose a novel method named the quantum harmonic oscillator model for simulation of intercity population mobility(QHO-IPM).QHO-IPM describes the intercity population mobility as being affected by coupled driving factors that work as a multioscillator-coupled quantum harmonic oscillator system,which is further transformed by the oscillation process of an oscillator,namely,the breaking point of intercity population *** intercity population mobility among seven cities in the Beijing-Tianjin-Hebei region and its surrounding region is taken as an example for verifying the *** experimental results show that(1)compared with the reference methods(the autoregressive integrated moving average(ARIMA)and long and short-term memory(LSTM)models),the QHO-IPM achieves better simulation performance regarding intercity population mobility in terms of both overall trend and mutation.(2)The simulation error in the QHO-IPM for different-level intercity population mobility is small and stable,which illustrates the weak sensitivity of the QHO-IPM to intercity population mobility under different structures.(3)The discussion regarding the influence degree of different driving factors reveals the significant“one dominant and multiple auxiliary”factor pattern of driving factors on intercity population mobility in the study *** proposed method has the potential to provide valuable support for understanding intercity population mobility laws and related de

关键词： intercity population mobility coupling driving factors quantum harmonic oscillator model probability distribution pattern optimization strategy

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Optimal rejection of bounded perturbations in linear leader-following consensus protocol: invariant ellipsoid method

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Science China(information Sciences) 2024年第8期67卷 24-34页

作者： Siyuan WANG Andrey POLYAKOV Min LI Gang ZHENG Driss BOUTAT INSA centre Val de Loire INRIA

The objective of the invariant ellipsoid method is to minimize the smallest invariant and attractive set of a linear control system operating under the influence of bounded external disturbances. This study extends the application of this method to address the leader-following consensus problem. Initially, a linear control protocol is designed for the multi-agent system in the absence of disturbances. Subsequently, in the presence of bounded disturbances, by employing a similar linear control protocol, a necessary and sufficient condition is introduced to derive the optimal control parameters for the multi-agent system such that the state of followers converges to and remains in a minimal invariant ellipsoid around the state of the leader.

关键词： disturbance invariant ellipsoid leader-following consensus multi-agent system

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Solid-state non-volatile memories based on vdW heterostructure-based vertical-transport ferroelectric field-effect transistors

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Science China(information Sciences) 2024年第6期67卷 198-206页

作者： Qiyu YANG Zheng-Dong LUO Fei XIAO Junpeng ZHANG Dawei ZHANG Dongxin TAN Xuetao GAN Yan LIU Zhufei CHU Yinshui XIA Genquan HAN Hangzhou Institute of Technology Xidian University State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology School of MicroelectronicsXidian University School of Artificial Intelligence Xidian University School of Materials Science and Engineering University of New South Wales (UNSW) Sydney ARC centre of Excellence in Future Low-Energy Electronics Technologies (FLEET) University of New South Wales (UNSW) Sydney Key Laboratory of Light Field Manipulation and information Acquisition Ministry of Industry and Information Technologyand Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical University Faculty of Electrical Engineering and Computer Science Ningbo University

Driven by the explosive development of data-centric computation applications, it is becoming urgent to develop in-memory computing devices that are beyond the von Neumann architecture with an arrangement of separated logic and memory components. The transistor-type solid-state non-volatile memories,such as ferroelectric field-effect transistors(Fe FETs), have long been regarded as a competitive candidate for future in-memory computing architectures. However, the density scaling towards high-density arrays would require advanced Fe FETs with reduced footprints, which remains a great challenge so far. Here, a vertical-transport(VT) Fe FET that flips the charge transport channel perpendicular to the substrate plane is proposed, in which a ferroelectric gate and a van der Waals(vd W) heterojunction channel are vertically integrated, effectively reducing the device footprints. The proposed VT-Fe FET shows not only the robust binary non-volatile memory states but also several key synaptic functionalities at the device level. An artificial neural network with supervised learning was simulated based on the device conductance switching properties,showing excellent classification accuracy for the MNIST handwritten digits. These findings suggest that the proposed VT-Fe FET could offer a new solution for future non-volatile memories as well as more advanced neuromorphic systems.

关键词： vdW heterostructure non-volatile memory vertical-transport transistor ferroelectric field-effect transistor memristive devices

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