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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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Synthesizing and controlling helical indirect exchange interactions at nonequilibrium

arXiv

引用

arXiv 2018年

作者： Liu, Tingting Ren, Jie Tong, Peiqing Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 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 Shanghai200092 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 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-WohlmanAharony 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. Copyright © 2018, The Authors. All rights reserved.

关键词： Embedded systems

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A Survey of Knowledge Enhanced Pre-trained Language Models

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ACM Transactions on Asian and Low-Resource Language Information Processing 1000年

作者： Jian Yang Xinyu Hu Gang Xiao Yulong Shen Computer Science and Technology Xidian University Xi’an China National Key Laboratory for Complex Systems Simulation Beijing China

Pre-trained language models learn informative word representations on a large-scale text corpus through self-supervised learning, which has achieved promising performance in fields of natural language processing (NLP) after fine-tuning. These models, however, suffer from poor robustness and lack of interpretability. We refer to pre-trained language models with knowledge injection as knowledge-enhanced pre-trained language models (KEPLMs). These models demonstrate deep understanding and logical reasoning and introduce interpretability. In this survey, we provide a comprehensive overview of KEPLMs in NLP. We first discuss the advancements in pre-trained language models and knowledge representation learning. Then we systematically categorize existing KEPLMs from three different perspectives. Finally, we outline some potential directions of KEPLMs for future research.

关键词： natural language processing pre-trained language models symbolic knowledge knowledge enhanced pre-trained language models

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Screening of metal-modified biochars for practical phosphorus recovery

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Science of the Total Environment 2024年 956卷 177342页

作者： Li, Man Xie, Qian Xu, Fangxi Zhang, Yan Zhuang, Zechao Xu, Jiawei Xiang, Hai Li, Yongfu Cai, Yanjiang Chen, Zuliang Yu, Bing State Key Laboratory of Subtropical Silviculture Zhejiang A&F University Hangzhou311300 China Zhejiang A&F University Hangzhou311300 China Zhejiang Taizhou Ecological and Environmental Monitoring Center Taizhou318000 China Department of Chemistry Tsinghua University Beijing100084 China Jiangsu Key Laboratory of Numerical Simulation of Large Scale Complex Systems and School of Chemistry and Materials Science Nanjing Normal University Nanjing210023 China Fujian Key Laboratory of Pollution Control and Resource Reuse School of Environmental and Resource Sciences Fujian Normal University Fujian Province Fuzhou350007 China

The utilization of metal-modified biochars (MBCs) for practical phosphorus recovery has attracted significant research interest recently. However, the optimal choice of metals and modification methods for MBCs remains unclear. This study addresses this gap by comparing the phosphate adsorption capabilities of various MBCs using real municipal wastewater. The results show that zinc-modified biochar exhibits superior phosphate adsorption compared to biochars modified with calcium, magnesium, aluminum, and iron. Specifically, zinc-modified biochar prepared through metal-mediated biomass pyrolysis with alkaline soaking (ZnBC-OH) demonstrates the highest adsorption capacity, achieving 36.6 mg P/g in wastewater with a phosphate concentration of 5 mg P/L. This performance surpasses that of previously reported non-lanthanide modified biochars and is comparable to lanthanide-modified biochars. Mechanistic investigations reveal that the exceptional performance of ZnBC-OH is due to the presence of highly dispersed ZnO sites, which facilitate the formation of Zn3(PO4)2·4H2O precipitation, effectively retaining phosphate. Furthermore, a techno-economic analysis indicates that using ZnBC-OH in a fixed-bed column system can reduce phosphate levels from 6 mg L−1 to below 0.5 mg L−1 at a cost of 1.834 USD per ton of secondary treated wastewater, underscoring its promising application potential. © 2024 Elsevier B.V.

关键词： Wastewater treatment

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A Distributed Approximation Algorithm for the Total Dominating Set Problem 1

引用

18th International Conference on Algorithmic Aspects in Information and Management, AAIM 2024

作者： Wang, Limin Zhang, Zhao Du, Donglei Mao, Yaping Zhang, Xiaoyan School of Mathematical Sciences Henan Institute of Science and Technology Xinxiang453003 China College of Mathematics and Computer Sciences Zhejiang Normal University Zhejiang321004 China Faculty of Management University of New Brunswick Fredericton E3B 5A3 New Brunswick Canada School of Mathematics and Statistics Qinghai Normal University Qinghai810008 China Academy of Plateau Science and Sustainability Xining Qinghai810008 China School of Mathematical Science and Institute of Mathematics Key Laboratory of Ministry of Education Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Jiangsu210023 China

ISBN: (数字)9789819777983

ISBN: (纸本)9789819777976

Given a network graph G=(V,E), a subset T⊆V is said to be a total dominating set (TDS) if every v∈V is adjacent to at least one node in T. In this paper, we present a distributed algorithm for the TDS problem via the LP relaxation techniques. For a positive integer k and maximum degree Δ, the proposed algorithm outputs a fractional total dominating set of expected size O(kΔ2k)|TDSOPT|. The distributed algorithm runs in O(k2) communication rounds, and the algorithm use messages of size O(logΔ). The fractional solution is then rounded to obtain an integer total dominating set for the original problem. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Consensus algorithm

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Bottomonium-like tetraquarks in a chiral quark model

arXiv

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arXiv 2022年

作者： Yang, Gang Ping, Jialun Segovia, Jorge Department of Physics Zhejiang Normal University Jinhua321004 China Department of Physics Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide SevillaE-41013 Spain

The low-lying bottomonium-like tetraquarks b(Equation presented)q(Equation presented) (q = u, d, s) with spin-parity JP = 0+, 1+ and 2+, and isospin I = 0, 1 or 1/2, are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body S-wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the b(Equation presented)q(Equation presented) (q = u, d) tetraquark system, we found resonance states of B(*)(Equation presented)(*), Υω, Υρ and ηbρ nature with all possible I(JP) quantum numbers. Their masses are generally located in the energy range 11.0 − 11.3 GeV and their widths are less than 10 MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than 1.5 MeV, are obtained in both b(Equation presented)u(Equation presented) and b(Equation presented)s(Equation presented) tetraquark systems. Particularly, four radial excitations of ΥK∗ and ηbK∗ are found at ∼ 11.1 GeV in JP = 0+, 1+ and 2+ channels of b(Equation presented)u(Equation presented) system. One Υ(1S)φ(2S) resonance state is obtained at 11.28 GeV in the JP = 1+ sector. Copyright © 2022, The Authors. All rights reserved.

关键词： Hadrons

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Charmoniumlike tetraquarks in a chiral quark model

arXiv

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arXiv 2023年

The lowest-lying charmonium-like tetraquarks (Equation presented) (q = u, d) and (Equation presented), with spin-parity JP = 0+, 1+ and 2+, and isospin I = 0 and 1, are systematically investigated within the theoretical framework of complex-scaling range for a chiral quark model that has already been successfully applied in former studies of various tetra- and penta-quark systems. A four-body S-wave configuration which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color wave functions, is comprehensively considered. Several narrow resonances are obtained in each tetraquark channel when a fully coupled-channel computation is performed. We tentatively assign theoretical states to experimentally reported charmonium-like signals such as X(3872), Zc(3900), X(3960), X(4350), X(4685) and X(4700). They can be well identified as hadronic molecules;however, other exotic components which involve, for instance, hidden-color channels or diquark-antidiquark structures play a considerable role. Meanwhile, two resonances are obtained at 4.04 GeV and 4.14 GeV which may be compatible with experimental data in the energy interval 4.0−4.2 GeV. Furthermore, the X(3940) and X(4630) may be identified as color compact tetraquark resonances. Finally, we also find few resonance states in the energy interval from 4.5 GeV to 5.0 GeV, which would be awaiting for discovery in future experiments. Copyright © 2023, The Authors. All rights reserved.

关键词： Germanium alloys

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Spring festival points the way to cleaner air in China

arXiv

引用

arXiv 2020年

作者： Wang, Siwen Su, Hang Streets, David G. Zhang, Qiang Lu, Zifeng He, Kebin Andreae, Meinrat O. Pöschl, Ulrich Cheng, Yafang Max Planck Institute for Chemistry Mainz55128 Germany Energy Systems Division Argonne National Laboratory LemontIL60439 United States Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System Science Tsinghua University Beijing100084 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China Scripps Institution of Oceanography University of California San Diego San DiegoCA92093 United States

Human migration during the Chinese Spring Festival (SF) is the largest collective human activity of its kind in the modern era-involving about one-tenth of the world population and over six percent of the earth's land surface area. The festival results in a drop of air pollutant emissions that causes dramatic changes of atmospheric composition over China's most polluted regions. Based on satellite and in-situ measurements for the years 2005-2019 over 50 cities in eastern China, we find that the atmospheric NO2 pollution dropped by ~40% during the SF week, and fine particulate matter (PM2.5) decreased by ~30% in the following week, reflecting the effectiveness of precursor emission controls on the mitigation of secondary PM2.5 formation. However, although human activity and emissions are at the lowest level, air pollution over eastern China during the SF still far exceeds that over other worldwide pollution hotspots. Our analyses suggest that measures based solely on end-of-pipe controls and industry upgrades may not suffice to meet air quality goals. Further cleaning of the air in China depends fundamentally on sustainable advances in both heavy industry upgrades and clean energy transition. Copyright © 2020, The Authors. All rights reserved.

关键词： Air cleaners

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The sQ¯ q¯ q (q = u, d;Q = c, b) tetraquarks in the chiral quark model

arXiv

引用

arXiv 2021年

The low-lying sQq¯q¯ (q = u, d, Q = c, b) tetraquark states with JP = 0+, 1+ and 2+, and in the isoscalar and isovector sectors, are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron and multiquark phenomenology, and thus all results presented here are pure predictions. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account;this includes meson-meson, diquark-antidiquark and K-type arrangements of quarks with all possible color wave functions in four-body sector. Among the different numerical techniques to solve the Schrödinger-like 4-body bound state equation, we use a variational method in which the trial wave function is expanded in complex-range Gaussian basis functions, because its simplicity and flexibility. Several compact bound states and narrow resonances are found in both charm-strange csq¯q¯ and bottom-strange bsq¯q¯ tetraquark sectors, most of them as a product of the strong coupling between the different channels. The so-called X0,1(2900) signals, recently found by the LHCb collaboration, are unstable in our formalism with several candidates in the single-channel computations. Copyright © 2021, The Authors. All rights reserved.

关键词： Hadrons

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Hidden-charm tetraquarks with strangeness in the chiral quark model

arXiv

引用

arXiv 2021年

作者： Yang, Gang Ping, Jialun Segovia, Jorge Department of Physics Zhejiang Normal University Jinhua321004 China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide SevillaE-41013 Spain

The hidden-charm tetraquarks with strangeness, ccs ¯ q¯ (q = u, d), in JP = 0+, 1+ and 2+ are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron and multiquark phenomenology. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account;this includes meson-meson, diquark-antidiquark and K-type arrangements of quarks with all possible color wave functions in four-body sector. Among the different numerical techniques to solve the Schrödinger-like 4-body bound state equation, we use a variational method in which the trial wave function is expanded in complex-range Gaussian basis functions, which is characterized by its simplicity and flexibility. This theoretical framework has already been used to study different kinds of multiquark systems, such as the hidden-charm pentaquarks, Pc+, and doubly-charmed tetraquarks, Tcc+. The recently reported Zcs states by the BESIII and LHCb collaborations are generally compatible with either compact tetraquark or hadronic molecular resonance configurations in our investigation. Moreover, several additional exotic resonances are found in the mass range between 3.8 GeV and 4.6 GeV. Copyright © 2021, The Authors. All rights reserved.

关键词： Hadrons

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