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arXiv 2023年

作者： Cao, Kaiyuan Hu, Yayun Tong, Peiqing Yang, Guangwen Zhejiang Lab Hangzhou311100 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Computer Science and Technology Tsinghua University Haidian District Beijing100084 China

We investigate the dynamical relaxation behavior of the two-point correlation in extended XY models with a gapless phase after quenches from various initial states. Specifically, we study the XY chain with gapless phase induced by the additional interactions: Dzyaloshinskii-Moriya interaction and XZY-YZX type of three-site interaction. When quenching from the gapped phase, we observe that the additional interactions have no effect on the relaxation behavior. The relaxation behavior is δCmn(t) ∼ t−3/2 and ∼ t−1/2 for the quench to the commensurate phase and the incommensurate phase, respectively. However, when quenching from the gapless phase, we demonstrate that the scaling behavior of δCmn(t) is changed to ∼ t−1 for the quench to the commensurate phase, and the decay of δCmn(t) follows ∼ t−1 or ∼ t−1/2 for the quench to the incommensurate phase depending on the parameters of pre-quench Hamiltonian. We also establish the dynamical phase diagrams based on the dynamical relaxation behavior of δCmn(t) in the extended XY models. Copyright © 2023, The Authors. All rights reserved.

关键词： Quenching

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Empirical estimates of regional carbon budgets imply reduced global soil heterotrophic respiration

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National science Review 2021年第2期8卷 60-73页

作者： Philippe Ciais Yitong Yao Thomas Gasser Alessandro Baccini Yilong Wang Ronny Lauerwald Shushi Peng Ana Bastos Wei Li Peter A.Raymond Josep G.Canadell Glen P.Peters Rob J.Andres Jinfeng Chang Chao Yue A.Johannes Dolman Vanessa Haverd Jens Hartmann Goulven Laruelle Alexandra G.Konings Anthony W.King Yi Liu Sebastiaan Luyssaert Fabienne Maignan Prabir K.Patra Anna Peregon Pierre Regnier Julia Pongratz Benjamin Poulter Anatoly Shvidenko Riccardo Valentini Rong Wang Grégoire Broquet Yi Yin Jakob Zscheischler Bertrand Guenet Daniel S.Goll Ashley-P.Ballantyne Hui Yang Chunjing Qiu Dan Zhu State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F University CSIRO Oceans and Atmosphere 15. Institute for Geology CEN—Center for Earth System Research and SustainabilityUniversity of Hamburg 16. Department of Earth System ScienceStanford University 17. Department of Earth System ScienceStanford UniversityStanford 18. School of Geographical SciencesNanjing University of Information Science and Technology 19. Department of Ecological SciencesVrije Universiteit Amsterdam 20. Research Institute for Global ChangeJAMSTEC Laboratoire des Sciences du Climat et de l'Environnement CEA-CNRS-UVSQ-UPSACLAY Center for Environmental Remote Sensing Chiba University Institute of Soil Science and Agrochemistry Siberian Branch of the Russian Academy of Sciences (SB RAS) Tuva State University Republic of Tuva Max Planck Institute for Meteorology NASA Goddard Space Flight Center Biospheric Sciences Lab. 26. Department for Innovation in BiologicalAgro-food and Forest systems (DIBAF)University of Tuscia RUDN University Department of Environmental Science and Engineering Shanghai Key Laboratory of Atmospheric Particle Pollution and PreventionInstitute of Atmospheric SciencesFudan University 29. Division of Geological and Planetary SciencesCalifornia Institute of Technology 30. Climate and Environmental Physics and Oeschger Centre for Climate Change ResearchUniversity of Bern 31. Department of Ecosystem and Conservation Sci

Resolving regional carbon budgets is critical for informing land-based mitigation policy. For nine regions covering nearly the whole globe, we collected inventory estimates of carbon-stock changes complemented by satellite estimates of biomass changes where inventory data are missing. The net land–atmospheric carbon exchange(NEE) was calculated by taking the sum of the carbon-stock change and lateral carbon fluxes from crop and wood trade, and riverine-carbon export to the ocean. Summing up NEE from all regions, we obtained a global ‘bottom-up’ NEE for net land anthropogenic CO2uptake of –2.2 ± 0.6 Pg C yr-1consistent with the independent top-down NEE from the global atmospheric carbon budget during 2000–2009. This estimate is so far the most comprehensive global bottom-up carbon budget accounting, which set up an important milestone for global carbon-cycle studies. By decomposing NEE into component fluxes, we found that global soil heterotrophic respiration amounts to a source of CO2of 39 Pg C yr-1with an interquartile of 33–46 Pg C yr-1—a much smaller portion of net primary productivity than previously reported.

关键词： carbon budget human appropriation of ecosystems soil carbon

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Synthesizing and controlling helical indirect exchange interactions out of equilibrium

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Physical Review B 2018年第18期98卷 184426-184426页

作者： Tingting Liu Jie Ren Peiqing Tong Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 P. R. China Center for Phononics and Thermal Energy Science China-EU Joint Center for Nanophononics Shanghai Key Laboratory of Special Artificial Microstructure Materials and Technology School of Physics Science and Engineering Tongji University Shanghai 200092 P. R. China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 P. R. China

We study the nonequilibrium effects of spin and/or electric currents on the helical indirect exchange interactions of local spins that embedded in general open electronic systems. Especially, besides the synthesized anisotropic Heisenberg interactions, we find that the synthetic helical indirect exchange interactions possess two parts: antisymmetric (Dzyaloshinskii-Moriya interaction) and symmetric (Kaplan-Shekhtman-Entin-Wohlman-Aharony interaction), which are all formulated in terms of Keldysh nonequilibrium Green's functions. The presence of either spin-orbit coupling or spin polarized currents alone is able to synthesize and control the antisymmetric Dzyaloshinskii-Moriya exchange interactions, as the same direction as spin splitting. However, the appearance of symmetric Kaplan-Shekhtman-Entin-Wohlman-Aharony interactions requires both, i.e., the spin-orbit coupling and spin polarized currents with different splitting directions. Our results show the detailed scheme of controlling the sign, magnitude, and direction of indirect Dzyaloshinskii-Moriya vectors and Kaplan-Shekhtman-Entin-Wohlman-Aharony interactions at nonequilibrium in open quantum devices.

关键词： Dzyaloshinskii-Moriya interaction Exchange interaction Open quantum systems RKKY interaction Rashba coupling

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Autonomous migration of virtual machine based on OpenStack

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International Journal of Hybrid Information technology 2016年第8期9卷 65-84页

作者： Zhou, Li Yu, Zhuoer Zhang, Jilin Wan, Jian Wu, Yusen School of Computer and Technology Hangzhou Dianzi University Hangzhou310018 China Key Laboratory of Complex Systems Modeling and Simulation Ministry of Education Hangzhou China College of Electrical Engineering Zhejiang University Hangzhou310058 China School of Information and Electronic engineering Zhejiang University of Science & Technology Hangzhou310023 China Zhejiang Provincial Engineering Center on Media Data Cloud Processing and Analysis HangzhouZhejiang China

For the problem of compute nodes load unbalance leads to the overload node impact VM performance and the underload node waste electrical energy. Dynamic VM consolidation is an efficient approach for improving the utilization of servers and reducing energy costs. In this paper, we introduce dynamic consolidation into OpenStack and implement AMVM based on OpenStack. AMVM collect and analyze all performance data of VM and compute node in OpenStack. Then AMVM automatically schedules VM live migrate to the most appropriate node according to the real-time load of all compute nodes. Then we use hybrid-copy instead of pre-copy in AMVM to improve the efficiency of VM live migration. Finally, we analyze the performance of hybrid-copy, hybrid-copy can reduce page faults compared with post-copy and reduce total data transferred compared with pre-copy. © 2016 SERSC.

关键词： Virtual machine

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Visualization of signalized intersections in driving simulator and validity of driving behaviors in virtual environments

Advances in Transportation Studies

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Advances in Transportation Studies 2011年第26期 17-28页

作者： Yan, X. Abdel-Aty, M. Guo, D. Radwan, E. MOE Key Laboratory for Transportation Complex Systems Theory and Technology Beijing Jiaotong University Beijing 100044 China Department of Civil and Environmental Engineering University of Central Florida Orlando FL 32816-2450 United States Computer Science Program College of Business Florida Gulf Coast University 10501 FGCU Boulevard South Fort Myers FL 33965-6565 United States Center for Advanced Transportation Systems Simulation University of Central Florida Orlando FL 32816-2450 United States

Visualization of highway traffic environments in virtual reality plays a key role on fidelity of simulation and validity of driving behaviors in driving simulator studies. This paper describes a procedure to replicate a signalized intersection with many complex features into a driving simulator's 3-D databases through building a graphical visual database, constructing a road motion database, and creating simulated traffic. The validity of the visualization was assessed via the comparison of the drivers' speeds in the simulator and the speed data at the real intersection. It was found that both speed data follow normal distributions and have equal means for each intersection approach;however, that the speeds measured in the driving simulator have a larger variability than those measured in the field. The users' subjective evaluation results indicated that 92% subjects could recognize the simulated intersection in the driving simulator experiment. Therefore, the strategy of geo-specific environment modeling would be useful for studying driving behaviors in virtual environments.

关键词： Visualization

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Progress and prospects of applied research on physical geography and the living environment in China over the past 70 years (1949-2019)

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Journal of Geographical sciences 2021年第1期31卷 3-45页

作者： CHEN Fahu WU Shaohong CUI Peng CAI Yunlong ZHANG Yili YIN Yunhe LIU Guobin OUYANG Zhu MA Wei YANG Linsheng WU Duo LEI Jiaqiang ZHANG Guoyou ZOU Xueyong CHEN Xiaoqing TAN Minghong WANG Xunming BAO Anming CHENG Weixin DANG Xiaohu WEI Binggan WANG Guoliang WANG Wuyi ZHANG Xingquan LIU Xiaochen LI Shengyu Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchCASBeijing 100101China CAS Centre for Excellence in Tibetan Plateau Earth Sciences Beijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100190China Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101China Key Laboratory of Land Surface Pattern and Simulation CASBeijing 100101China Institute of Mountain Hazards and Environment CASChengdu 610041China College of Urban and Environmental Sciences Peking UniversityBeijing 100871China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Northwest A&F UniversityYangling 712100ShaanxiChina Northwest Institute of Eco-Environment and Resources CASLanzhou 730000China Key Laboratory of Western China’s Environmental Systems(Ministry of Education) College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China Xinjiang Institute of Ecology and Geography CASUrumqi 830011China The Geographical Society of China Beijing 100101China Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China College of Geology and Environment Xi'an University of Science and TechnologyXi’an 710054China Institute of Tibetan Plateau Research CASBeijing 100101China

Physical geography is a basic research subject of natural sciences. Its research object is the natural environment which is closely related to human living and development, and China’s natural environment is complex and diverse. According to national needs and regional development, physical geographers have achieved remarkable achievements in applied basis and applied research, which also has substantially contributed to the planning of national economic growth and social development, the protection of macro ecosystems and resources, and sustainable regional development. This study summarized the practice and application of physical geography in China over the past 70 years in the following fields: regional differences in natural environments and physical regionalization;land use and land cover changes;natural hazards and risk reduction;process and prevention of desertification;upgrading of medium-and low-yield fields in the Huang-Huai-Hai region;engineering construction in permafrost areas;geochemical element anomalies and the prevention and control of endemic diseases;positioning and observation of physical geographical elements;and identification of geospatial differentiation and geographical detectors. Furthermore, we have proposed the future direction of applied research in the field of physical geography.

关键词： physical geography scientific practice applied research regional development national strategy

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Visualization of signalized intersections in driving simulator and validity of driving behaviors in virtual environments

Advances in Transportation Studies

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Advances in Transportation Studies 2012年第26期 17-28页

关键词： Visualization

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Relaxation dynamics in the alternating XY chain following a quantum quench

arXiv

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arXiv 2023年

作者： Cao, Kaiyuan Hu, Yayun Tong, Peiqing Yang, Guangwen Liu, Peng Zhejiang Lab Hangzhou311100 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Computer Science and Technology Tsinghua University Haidian District Beijing100084 China College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China

We investigate the relaxation dynamics of the fermion two-point correlation function Cmn(t) = 〈ψ(t)|c†mcn|ψ(t)〉 in the XY chain with alternating nearest-neighbor hopping interaction after a quench. We find that the deviation δCmn(t) = Cmn(t) − Cmn(∞) decays with time following the power law behavior t−µ, where the exponent µ depends on whether the quench is to the commensurate phase (µ = 1) or incommensurate phase (µ = 1/2). This decay of δCmn(t) arises from the transient behavior of the double-excited quasiparticle occupations and the transitions between different excitation spectra. Furthermore, we find that the steady value Cmn(∞) only involves the average fermion occupation numbers (i.e. the average excited single particle) over the time-evolved state, which are different from the ground state expectation values. We also observe nonanalytic singularities in the steady value Cmn(∞) for the quench to the critical points of the quantum phase transitions (QPTs), suggesting its potential use as a signature of QPTs. Copyright © 2023, The Authors. All rights reserved.

关键词： Ground state

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Dynamical relaxation behavior of an extended XY chain with a gapless phase following a quantum quench

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Physical Review B 2024年第2期109卷 024303-024303页

作者： Kaiyuan Cao Yayun Hu Peiqing Tong Guangwen Yang Zhejiang Lab Hangzhou 311100 People's Republic of China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210023 People's Republic of China and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People's Republic of China Zhejiang Lab Hangzhou 311100 People's Republic of China and Department of Computer Science and Technology Tsinghua University Haidian District Beijing 100084 People's Republic of China

We investigate the dynamical relaxation behavior of the two-point correlation in extended XY models with a gapless phase after quenches from various initial states. Specifically, we study the XY chain with gapless phase induced by the following additional interactions: Dzyaloshinskii-Moriya interaction and the XZY-YZX type of three-site interaction. When quenching from the gapped phase, we observe that the additional interactions have no effect on the relaxation behavior. The relaxation behavior is δCmn(t)∼t−3/2 and ∼t−1/2 for the quench to the commensurate phase and the incommensurate phase, respectively. However, when quenching from the gapless phase, we demonstrate that the scaling behavior of δCmn(t) is changed to ∼t−1 for the quench to the commensurate phase, and the decay of δCmn(t) follows ∼t−1 or ∼t−1/2 for the quench to the incommensurate phase depending on the parameters of prequench Hamiltonian. We also establish the dynamical phase diagrams based on the dynamical relaxation behavior of δCmn(t) in the extended XY models.

关键词： Dynamical phase transitions Dzyaloshinskii-Moriya interaction Quantum quench XY model

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Hidden-bottom pentaquarks

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Physical Review D 2019年第1期99卷 014035-014035页

作者： Gang Yang Jialun Ping Jorge Segovia Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics Tsinghua University Beijing 100084 People’s Republic of China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Institut de Física d’Altes Energies (IFAE) and Barcelona Institute of Science and Technology (BIST) Universitat Autònoma de Barcelona E-08193 Bellaterra (Barcelona) Spain

The LHCb Collaboration has recently reported strong evidences of the existence of pentaquark states in the hidden-charm baryon sector, the so-called Pc(4380)+ and Pc(4450)+ signals. Five-quark bound states in the hidden-charm sector were explored by us using, for the quark-quark interaction, a chiral quark model which successfully explains meson and baryon phenomenology, from the light to the heavy quark sector. We extend herein such study into the hidden-bottom pentaquark sector, analyzing possible bound-states with spin-parity quantum numbers JP=12±, 32± and 52±, and in the 12 and 32 isospin sectors. We do not find positive parity hidden-bottom pentaquark states; however, several candidates with negative parity are found with dominant baryon-meson structures Σb(*)B¯(*). Their inner structures have been also analyzed with the computation of the distance among any pair of quarks within the bound-state. This exercise reflects that molecular-type bound-states are favored when only color-singlet configurations are considered in the coupled-channels calculation whereas some deeply-bound compact pentaquarks can be found when hidden-color configurations are added. Finally, our findings resemble the ones found in the hidden-charm sector but, as expected, we find in the hidden-bottom sector larger binding energies and bigger contributions of the hidden-color configurations.

关键词： Particle interactions Quantum chromodynamics Quark model Strong interaction

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