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Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing Ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati Lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue Li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier Liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong Li Bifang Liu Mingjun Liu Xing Liu Yuan Liu Zhu Liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria Lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui Li Junfei Li Longhui Li Maoshun Li Wei Li Zhengda Li Tianying Lian Congzhan Liu Heyang Liu Huaqiu Liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan Liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences university of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics institute of High Energy Physics Chinese Academy of Sciences institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck institute for Extraterrestrial Physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of Physics university of Hong Kong School of Physics and Astronomy university of Leicester School of Physics and Astronomy Sun Yat-sen university Department of Physics Anhui Normal university Shanghai institute of Technical Physics Chinese Academy of Sciences Physics Department Tsinghua university Nevada Center for Astrophysics university of Nevada Las Vegas Department of Physics and Astronomy university of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy university of cape town Department of Physics university of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou university Cosmic Dawn Center (DAWN) Niels Bohr institute university of Copenhagen Department of Physics and Astronomy Rutgers the State university of New Jersey institute for Cosmic Ray Research The university of Tokyo ESA/ESTEC Department of Astronomy School of Physics Huazhong university of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney institute for Astronomy School of Physics The university of Sydney Department of Astronomy Xiamen university institute for Frontiers in Astronomy and Astrophysics Beijing Normal university Department of Astronomy university of Science and Technology School of Astronomy and Space Sciences university of Science and Technology of China institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan university Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

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The immune response to SARS-CoV-2 in people with HIV

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Cellular & Molecular Immunology 2024年第2期21卷 184-196页

作者： Maxine A.Höft Wendy A.Burgers Catherine Riou institute of Infectious Disease and Molecular Medicine University of Cape TownCape TownSouth Africa Division of Medical Virology Department of PathologyUniversity of Cape TownCape TownSouth Africa Wellcome Centre for Infectious Diseases Research in Africa University of Cape TownCape TownSouth Africa

This review examines the intersection of the HIV and SARS-CoV-2 *** with HIV(PWH)are a heterogeneous group that differ in their degree of immune suppression,immune reconstitution,and viral *** COVID-19 in those with wellcontrolled HIV infection poses no greater risk than that for HIV-uninfected individuals,people with advanced HIV disease are more vulnerable to poor COVID-19 ***-19 vaccines are effective and well tolerated in the majority of PWH,though reduced vaccine efficacy,breakthrough infections and faster waning of vaccine effectiveness have been demonstrated in *** is likely a result of suboptimal humoral and cellular immune responses after *** with advanced HIV may also experience prolonged infection that may give rise to new epidemiologically significant variants,but initiation or resumption of antiretroviral therapy(ART)can effectively clear persistent ***-19 vaccine guidelines reflect these increased risks and recommend prioritization for vaccination and additional booster doses for PWH who are moderately to severely *** recommend continued research and monitoring of PWH with SARS-CoV-2 infection,especially in areas with a high HIV burden.

关键词： SARS-CoV-2 HIV Immune dysfunction Vaccine efficacy Prolonged infection Immunogenicity

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High-energy-density lithium manganese iron phosphate for lithium-ion batteries: Progresses, challenges, and prospects

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Journal of Energy Chemistry 2025年第1期100卷 1-17页

作者： Bokun Zhang Xiaoyun Wang Shuai Wang Yan Li Libo Chen Handong Jiao Zhijing Yu Jiguo Tu State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Research institute for Intelligent Wearable Systems The Hong Kong Polytechnic University institute of Advanced Structure Technology Beijing Institute of Technology

The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion *** manganese iron phosphate (LiMnxFe1-xPO4) has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy *** LiMnxFe1-xPO4has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap *** review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMnxFe1-xPO4to analyze reaction processes accurately and guide material ***,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMnxFe1-xPO4,including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology ***,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are *** importantly,it is expected to provide key insights into the development of high-performance and stable LiMnxFe1-xPO4materials,to achieve practical energy storage requirements.

关键词： Lithium manganese iron phosphate High energy density Lithium-ion batteries Reaction mechanism Tap density

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Observation of acoustic hybrid topological phases induced by the p-d orbital interactions

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 132-139页

作者： Xiao Xiang Feng Gao Yu-Gui Peng Peng Wu Zong-Lin Li Xue-Feng Zhu School of Physics and Innovation institute Huazhong University of Science and Technology

In spinless systems,growing attention has recently been attracted to synthetic gauge fields,which redefine the fundamental crystal symmetries by utilizing the projective algebraic ***,synthetic gauge fields have been commonly investigated in single orbital systems,and explorations on hybrid orbitals remain elusive in ***,we report the experimental observation of hybrid topological phases induced by hybrid synthetic gauge flux,which is formed by the interaction between p and d orbitals embedded in acoustic *** breaking the translation symmetries of Lxand/or Ly,we unambiguously demonstrate the first-order M?bius edge states and higher-order corner *** work establishes a platform for seeking exotic topological phases induced by hybrid-orbitals interactions and initializing the framework of hybrid-orbitalsrelated topological *** applications can be anticipated in scenarios such as high-quality sensing and robust wave trapping due to the stepwise energy distribution of the hybrid topological phase.

关键词： topological insulator synthetic gauge field projective symmetry corner states

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Unlocking the stable interface in aqueous zinc-ion battery with multifunctional xylose-based electrolyte additives

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Journal of Energy Chemistry 2025年第1期100卷 770-778页

作者： Xiaoqin Li Jian Xiang Lu Qiu Xiaohan Chen Yinkun Zhao Yujue Wang Qu Yue Taotao Gao Wenlong Liu Dan Xiao Zhaoyu Jin Panpan Li institute for Advanced Study Chengdu University School of Mechanical Engineering Chengdu University College of Food and Biological Engineering Chengdu University institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of China College of Materials Science and Engineering Sichuan University

The growth of dendrites and the side reactions occurring at the Zn anode pose significant challenges to the commercialization of aqueous Zn-ion batteries（AZIBs）. These challenges arise from the inherent conflict between mass transfer and electrochemical kinetics. In this study, we propose the use of a multifunctional electrolyte additive based on the xylose（Xylo） molecule to address these issues by modulating the solvation structure and electrode/electrolyte interface, thereby stabilizing the Zn anode. The introduction of the additive alters the solvation structure, creating steric hindrance that impedes charge transfer and then reduces electrochemical kinetics. Furthermore, in-situ analyses demonstrate that the reconstructed electrode/electrolyte interface facilitates stable and rapid Zn2+ion migration and suppresses corrosion and hydrogen evolution reactions. As a result, symmetric cells incorporating the Xylo additive exhibit significantly enhanced reversibility during the Zn plating/stripping process, with an impressively long lifespan of up to 1986 h, compared to cells using pure ZnSO4electrolyte. When combined with a polyaniline cathode, the full cells demonstrate improved capacity and long-term cyclic stability. This work offers an effective direction for improving the stability of Zn anode via electrolyte design, as well as highperformance AZIBs.

关键词： Solvation

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Substrate control in track registration and preservation:insights across the Triassic—Jurassic boundary in southern Africa

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Journal of Palaeogeography 2024年第2期13卷 351-371页

作者： Loyce Mpangala Miengah Abrahams Emese M.Bordy Department of Geological Sciences University of Cape TownCape TownSouth Africa

Tracks registration is influenced by the dynamic interplay between the pedal anatomy of the trackmaker,its behaviour,and the substrate conditions it interacts *** in substrate conditions,especially those linked to grain size and moisture content,often result in the most dramatic variations in track *** the upper Stormberg Group,main Karoo Basin of southern Africa,diverse trace fossils,primarily comprising Late Triassic—Early Jurassic dinosaur tracks,are *** studies have extensively documented individual ichnosites,investigating variations between sites over time,with recent studies suggesting that track abundance and anatomical fidelity increase *** the well-established link between substrate and track morphology,past studies have not specifically focused on substrate conditions,often emphasizing macro-sedimentary features ***,we examine the micro-sedimentary features of track-bearing units in the upper Stormberg Group using petrographic techniques to better understand the palaeosubstrate and its effect on fossil track registration and *** analysis revealed that very fine-grained sandstones and substrates modified by microbial activity tend to preserve tracks with greater abundance and/or higher anatomical ***,the prevalence of very fine-grained and microbially modified strata,and their associated track trends increases in younger stratigraphic *** the Triassic—Jurassic boundary in southern Africa,a boom in dinosaur track abundances is observed and credited to the proliferation of dinosaur populations during the Early *** findings,however,suggest that the observed local increase in track abundance(and anatomical fidelity)up-stratigraphy may be linked to substrate composition differences,which were ultimately controlled by large-scale changes in the palaeoenvironment from high-energy meandering fluvial to lower-energy aeolian-lacustrine settings in the L

关键词： Dinosaur tracks Footprint anatomical fidelity Micro-sedimentary features Substrate conditions Track registration Palaeoenvironmental context

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Constraints on holographic QCD phase transitions from PTA observations

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 71-78页

作者： Song He Li Li Sai Wang Shao-Jiang Wang Center for Theoretical Physics and College of Physics Jilin University School of Physical Science and Technology Ningbo University Max Planck institute for Gravitational Physics (Albert Einstein institute) CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of Sciences (UCAS) School of Physical Sciences University of Chinese Academy of Sciences (UCAS) Theoretical Physics Division Institute of High Energy Physics Chinese Academy of Sciences

The underlying physics of QCD phase transition in the early Universe remains largely unknown due to its strong-coupling nature during the quark-gluon plasma/hadron gas transition, yet a holographic model has been proposed to quantitatively fit the lattice QCD data while with its duration of the first-order phase transition(FoPT) left undetermined. At specific baryon chemical potential, the first-order QCD phase transition agrees with the observational constraint of baryon asymmetry. It, therefore, provides a scenario for phase transition gravitational waves(GWs) within the standard model of particle physics. If these background GWs could contribute dominantly to the recently claimed common-spectrum red noise from pulsar timing array(PTA) observations, the duration of this FoPT can be well constrained, and the associated primordial black holes are still allowed by current observations.

关键词： pulsar timing array QCD phase transition gravitational waves primordial black holes

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Viscoelastic modeling of the diffusion of polymeric pollutants injected into a pipe flow

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Acta Mechanica Sinica 2013年第2期29卷 166-178页

作者： T.Chinyoka O.D. Makinde Center for Research in Computational and Applied Mechanics university of cape town institute for Advanced Research in Mathematical Modeling and Computations Cape Peninsula University of Technology

This study focuses on the transient analysis of nonlinear dispersion of a polymeric pollutant ejected by an external source into a laminar pipe flow of a Newtonian liquid under axi-symmetric *** influence of density variation with pollutant concentration is approximated according to the Boussinesq approximation and the nonlinear governing equations of momentum,pollutant concentration are obtained together with and Oldroyd-B constitutive model for the polymer *** problem is solved numerically using a semi-implicit finite difference *** are presented in graphical form for various parameter values and given in terms of fluid velocity,pollutant concentration,polymer stress components,skin friction and wall mass transfer *** model can be a useful tool in understanding the dynamics of industrial pollution situations arising from improper discharge of hydrocarbon pollutants into,say,water *** model can also be quite useful for available necessary early warning methods for detecting or predicting the scale of pollution and hence help mitigate related damage downstream by earlier instituting relevant decontamination measures.

关键词： Axi-symmetric flow·Polymeric pollutant dispersion·Oldroyd-B model Buoyancy forces·Semi-implicit finite difference method

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Incompatible deformation field and Riemann curvature tensor

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Applied Mathematics and Mechanics(English Edition) 2017年第3期38卷 311-332页

作者： Bohua SUN Department of Mechanical Engineering Cape Peninsula University of Technology Cape Town 7535 South Africa

Compatibility conditions of a deformation field in continuum mechanics have been revisited via two different routes. One is to use the deformation gradient, and the other is a pure geometric one. Variations of the displacement vector and the displacement density tensor are obtained explicitly in terms of the Riemannian curvature tensor. The explicit relations reconfirm that the compatibility condition is equivalent to the vanishing of the Riemann curvature tensor and reveals the non-Euclidean nature of the space in which the dislocated continuum is imbedded. Comparisons with the theory of Kr¨oner and Le-Stumpf are provided.

关键词： compatibility condition Riemann curvature tensor deformation gradient Burgers vector dislocation density tensor

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Scaling laws of aquatic locomotion

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Science China(Physics,Mechanics & Astronomy) 2017年第10期60卷 27-33页

作者： BoHua Sun Department of Mechanical Engineering Cape Peninsula University of Technology Cape Town 8000 South Africa

In recent years studies of aquatic locomotion have provided some remarkable insights into the many features of fish swimming performances. This paper derives a scaling relation of aquatic locomotion CD(Re)~2 =(Sw)~2 and its corresponding log law and power law. For power scaling law,(Sw)~2 = β_nRe^((2-1)/n), which is valid within the full spectrum of the Reynolds number Re=UL/v from low up to high, can simply be expressed as the power law of the Reynolds number Re and the swimming number Sw=ωAL/v as Re ∝ (Sw)~σ,with σ=2 for creeping flows,σ=4/3 for laminar flows, σ=10/9 and σ=14/13 for turbulent flows. For log law this paper has derived the scaling law as Sw ∝ Re=(lnRe+1.287), which is even valid for a much wider range of the Reynolds number Re. Both power and log scaling relationships link the locomotory input variables that describe the swimmer's gait A;ω via the swimming number Sw to the locomotory output velocity U via the longitudinal Reynolds number Re, and reveal the secret input-output relationship of aquatic locomotion at different scales of the Reynolds number.

关键词： aquatic locomotion scaling law Reynolds number swimming number creeping flows laminar flows turbulent flows

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