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Fundamental Research 2024年第3期4卷 704-705页

作者： renxin xu State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China

In the past hundred years since 1900,with some sorts of fundamental symmetry,the combination of quantum theory and special relativity is successful in establishing the“standard model of particle physics”.In this era of multi-messenger astronomy(encompassing full electromagnetic waves,neutrinos,cosmic rays,and gravitational waves),it becomes increasingly important to explore the physics in strong gravity,which involves the integration of the standard model and the general *** mystery of powerful and brief flashes ofγ-rays,called gamma-ray bursts(GRBs),is one of such issues,often involving the birth of black holes and neutron ***(Large High Altitude Air Shower Observatory).

关键词： narrow establishing symmetry

Free Energy of Anisotropic Strangeon Stars

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Research in Astronomy and Astrophysics 2024年第2期24卷 50-57页

作者： Shichuan Chen Yong Gao Enping Zhou renxin xu Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsHuazhong University of Science and TechnologyWuhan 430074China

Can pulsar-like compact objects release further huge free energy besides the kinematic energy of rotation?This is actually relevant to the equation of state of cold supra-nuclear matter,which is still under hot *** energy is surely needed to understand various observations,such asγ-ray bursts,fast radio bursts and softγ-ray *** this paper,the elastic/gravitational free energy of solid strangeon stars is revisited for strangeon stars,with two anisotropic models to calculate in general *** is found that huge free energy(>10^(46)erg)could be released via starquakes,given an extremely small anisotropy((p_(t)-p_(r))/p_(r)~10^(-4),with pt/pr the tangential/radial pressure),implying that pulsar-like stars could have great potential of free energy release without extremely strong magnetic fields in the solid strangeon star model.

关键词： (stars:)pulsars general-methods numerical-(stars:)gamma-ray bursts general

The Precursor of GRB211211A:A Tide-induced Giant Quake?

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Research in Astronomy and Astrophysics 2024年第2期24卷 206-215页

作者： Enping Zhou Yong Gao Yurui Zhou Xiaoyu Lai Lijing Shao Weiyang Wang Shaolin Xiong renxin xu Shuxu Yi Garvin Yim Han Yue Zhen Zhang School of Physics Huazhong University of Science and TechnologyWuhan 430074China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China School of Physics Peking UniversityBeijing 100871China Research Center for Astronomy Hubei University of EducationWuhan 430205China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China School of Earth and Space Sciences Peking UniversityBeijing 100871China

The equilibrium configuration of a solid strange star in the final inspiral phase with another compact object is generally discussed,and the starquake-related issue is revisited,for a special purpose to understand the precursor emission of binary compact star merger events(e.g.,that of GRB211211A).As the binary system inspirals inward due to gravitational wave radiation,the ellipticity of the solid strangeon star increases due to the growing tidal field of its compact *** energy is hence accumulated during the inspiral stage which might trigger a starquake before the merger when the energy exceeds a critical *** energy released during such starquakes is calculated and compared to the precursor observation of GRB211211 *** result shows that the energy might be insufficient for binary strangeon-star case unless the entire solid strangeon star shatters,and hence favors a black hole-strangeon star scenario for *** timescale of the precursor as well as the frequency of the observed quasi-periodic-oscillation have also been discussed in the starquake model.

关键词： stars neutron-(stars:)gamma-ray burst general-black hole physics

聚氨酯上浆剂处理PBO纤维复合材料的界面性能

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材料工程 2024年第4期52卷 155-163页

作者：蒋磊徐任信吴书广刘国权丁安心陈杨武汉理工大学材料科学与工程学院武汉430070 宜昌测试技术研究所湖北宜昌443003 河南省特种防护材料重点实验室河南洛阳471023

为了提高聚对苯撑苯并二噁唑(poly-p-phenylenebenzobisoxazole,PBO)纤维/环氧树脂复合材料的界面性能,采用γ-氨丙基三乙氧基硅烷(KH550)改性水性聚氨酯得到上浆剂,然后对酸化后的PBO纤维进行表面涂覆处理。采用XPS和EDS分析PBO纤维表... 详细信息

为了提高聚对苯撑苯并二噁唑(poly-p-phenylenebenzobisoxazole,PBO)纤维/环氧树脂复合材料的界面性能,采用γ-氨丙基三乙氧基硅烷(KH550)改性水性聚氨酯得到上浆剂,然后对酸化后的PBO纤维进行表面涂覆处理。采用XPS和EDS分析PBO纤维表面的化学组成,利用SEM研究PBO纤维表面及其复合材料撕裂面的形貌,并对PBO纤维的单丝及复合材料的力学性能进行分析。结果表明:经过上浆剂包覆的PBO纤维表面活性基团明显增多,表面O/C(原子比)由0.16提升至0.25,上浆剂能有效修复纤维表面的缺陷;通过调控纤维表面上浆剂含量和结构,可使PBO纤维/环氧树脂单向复合材料的层间剪切强度提高到41.3 MPa,拉伸强度增加到1.70 GPa,相较于未处理的复合材料分别提高了44.9%和15.6%。

关键词： PBO纤维水性聚氨酯上浆剂界面性能剪切强度

Repeating fast radio bursts: Coherent circular polarization by bunches

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Science China(Physics,Mechanics & Astronomy) 2022年第8期65卷 148-157页

作者： Wei-Yang Wang Jin-Chen Jiang Jiguang Lu Heng xu Jiangwei xu Kejia Lee Jifeng Liu renxin xu School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing100871China CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang550025China Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing100049China

Fast radio bursts(FRBs) are millisecond-duration signals that are highly dispersed at distant galaxies. However, the physical origin of FRBs is still unknown. Coherent curvature emission by bunches, e.g., powered by starquakes, has already been proposed for repeating FRBs. It has the nature of understanding narrowband radiation exhibiting time-frequency drifting. Recently, a highly active FRB source, i.e., FRB 20201124A, was reported to enter a newly active episode and emit at least some highly circular-polarized bursts. In this study, we revisit the polarized FRB emission, particularly investigating the production mechanisms of a highly circular polarization(CP) by deriving the intrinsic mechanism and propagative effect. The intrinsic mechanisms of invoking charged bunches are approached with radiative coherence. Consequently, a highly CP could naturally be explained by the coherent summation of outcome waves, generated or scattered by bunches, with different phases and electric vectors. Different kinds of evolutionary trajectories are found on the Poincaré sphere for the bunch-coherent polarization, and this behavior could be tested through future observations. Cyclotron resonance can result in the absorption of R-mode photons at a low altitude region of the magnetosphere, and an FRB should then be emitted from a high-altitude region if the waves have strong linear polarization. Circularly polarized components could be produced from Faraday conversion exhibiting a λ-oscillation, but the average CP fraction depends only on the income wave, indicating a possibility of a highly circular-polarized income wave. The analysis could be welcome if extremely high(e.g., almost 100%) CP from repeating FRBs is detected in the future. Finally, the production of a bulk of energetic bunches in the pulsar-like magnetosphere is discussed, which is relevant to the nature of the FRB central engine.

关键词： fast radio burst radiation mechanism neutron stars

Three flavors in a triangle

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Science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 133-134页

作者： renxin xu School of Physics and Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The coupling between elementary units,either weak or strong,determines the nature of matter controlled by different *** for three fundamental interactions(gravitational,electromagnetic,and strong),all the gauge bosons to mediate the forces are massless,and we may simply approximate the interaction energy at short distances with a Coulomb-like form of V=-αi/r,with r the separation between units.

关键词： triangle gauge elementary

Strong matter: Rethinking philosophically

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 108-112页

作者： renxin xu School of Physics and Kavli Institute for Astronomy and Astrophysics Peking University

As we continue to comprehend the underlying nature of matter in different forms,human civilization develops *** matter in everyday life,the basic stuff of which was posited by speculators even before Socrates,is dominated by electromagnetic interaction,and it could hence be simply termed electric ***,gravitationally controlled systems(e.g.,galaxies and galaxy clusters)belong to gravitational matter,and atomic nuclei to strong matter.

关键词：物质哲学原子核天体物理学相互作用显微镜宇宙论重力

Advancing pulsar science with the FAST

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Science China(Physics,Mechanics & Astronomy) 2020年第2期63卷 156-158页

作者： JiGuang Lu KeJia Lee renxin xu CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Guizhou Radio Astronomy Observatory Chinese Academy of SciencesGuiyang 550025China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China Department of Astronomy School of PhysicsPeking UniversityBeijing 100871China

As the rump left behind after an extremely gravity-induced supernova of an evolved massive star,a pulsar is made of cool CBM(i.e.,compressed baryonic matter at a low temperature).Pulsars are not only testbeds for fundamental interactions(e.g.,the nature of gravity[1]and of the strong force at low energies[2]),but also essential tools for detecting nanoHz gravitational waves[3].The pulsar science,whatever,usually depends on the measurement of pulsar radiation,e.g.,pulsar monitoring and ***,searching new pulsars for further investigation is also an important focus of this research *** have a very good showing,and have never stopped presenting surprises since the first discovery in 1967,because of the continuing development of advanced facilities.

关键词： pulsar massive FAST

Causal propagation of signals in strangeon matter

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Science China(Physics,Mechanics & Astronomy) 2018年第8期61卷 82-88页

作者： JiGuang Lu EnPing Zhou XiaoYu Lai renxin xu CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China Key Laboratory of Radio Astronomy Chinese Academy of SciencesBeijing 100012China School of Physics and State Key Laboratory of Nuclear Science and Technology Peking UniversityBeijing 100871China School of Physics and Mechanical&Electrical Engineering Hubei University of EducationWuhan 430205China Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Kavil Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The state equation for strangeon matter is very stiff due to the non-relativistic nature of its particles and their repulsive interaction,such that pulsar masses as high as～3 M_⊙ would be expected. However, an adiabatic sound speed, c_s=(?P/?ρ)～(1/2), is usually superluminal in strangeon matter, and the dynamic response of a strangeon star(e.g., binary merger) is not tractable in numerical simulations. In this study, we examined signal propagation in strangeon matter and calculate the actual propagation speed, c_(signal).We found that the causality condition, c_(signal)< c, is satisfied and the signal speed is presented as a function of stellar radius.

关键词：繁殖速度信号物质原因非相对论相互作用动态反应数字模拟

Revise Thermal Winds of Remnant Neutron Stars in Gamma-Ray Bursts

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天文和天体物理学研究:英文版 2023年第9期23卷 142-147页

作者： Shuang Du Tingting Lin Shujin Hou renxin xu School of Mathematics and Computer Tongling UniversityTongling 244061China School of Foundation Zhejiang Shuren UniversityShaoxing 312028China School of Physics and Electronic Engineering Nanyang Normal UniversityNanyang 473061China School of Physics Peking UniversityBeijing 100871China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

It seems that the wealth of information revealed by the multi-messenger observations of the binary neutron star(NS)merger event,GW170817/GRB 170817A/kilonova AT2017gfo,places irreconcilable constraints to models of the prompt emission of this gamma-ray burst(GRB).The observed time delay between the merger of the two NSs and the trigger of the GRB and the thermal tail of the prompt emission can hardly be reproduced by these models *** argue that the merger remnant should be an NS(last for,at least,a large fraction of 1 s),and that the difficulty can be alleviated by the delayed formation of the accretion disk due to the absorption of high-energy neutrinos emitted by the NS and the delayed emergence of effective viscosity in the ***,we extend the consideration of the effect of the energy deposition of neutrinos emitted from the *** the NS is the central object of a GRB with a distance and duration similar to that of GRB 170817A,thermal emission of the thermal bubble inflated by the NS after the termination of accretion may be *** our scenario is verified,it would be of interest to investigate the cooling of nascent NSs.

关键词： (stars )gamma-ray burst general-(stars )gamma-ray burst individual(..,...)-stars neutron