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Supernova 1987A's Keyhole:A Long-lived Jet-pair in the Final Explosion Phase of Core-collapse Supernovae

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Research in Astronomy and Astrophysics 2024年第7期24卷 89-94页

作者： Noam Soker department of physics TechnionHaifa3200003Israel

I further study the manner by which a pair of opposite jets shape the“keyhole”morphological structure of the core-collapse supernova(CCSN)SN 1997A,now the CCSN remnant(CCSNR)*** doing so,I strengthen the claim that the jittering-jet explosion mechanism accounts for most,likely all,***“keyhole”structure comprises a northern low-intensity zone closed with a bright rim on its front and an elongated low-intensity nozzle in the *** rim-nozzle asymmetry is observed in some cooling flow clusters and planetary nebulae that are observed to be shaped by jets.I build a toy model that uses the planar jittering jets pattern,where consecutive pairs of jets tend to jitter in a common plane,implying that the accreted gas onto the newly born neutron star at the late explosion phase flows perpendicular to that *** allows for a long-lived jet-launching *** long-lasting jet-launching episode launches more mass into the jets that can inflate larger pairs of ears or bubbles,forming the main jets'axis of the CCSNR that is not necessarily related to a possible pre-collapse core rotation.I discuss the relation of the main jets'axis to the neutron star's natal kick velocity.

关键词： stars:massive (stars:)supernovae:general (stars:)supernovae:individual(SN 1987A) ISM:supernova remnants stars:jets

Two innovative equivalent statements of the third law of thermodynamics

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Chinese physics B 2024年第6期33卷 324-328页

作者：陈晓航周颖慧陈金灿 department of physics Xiamen UniversityXiamen 361005China

It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the heat capacity statement. It is pointed out that such three statements correspond to three thermodynamic parameters, which are, respectively, the entropy,temperature, and heat capacity, and can be obtained by extrapolating the experimental results of different parameters at ultralow temperatures to absolute zero. It is expounded that because there is no need for additional assumptions in the derivation of the Nernst equation, the Nernst theorem should be renamed as the Nernst statement. Moreover, it is proved that both the Nernst statement and the heat capacity statement are mutually deducible and equivalent, while the unattainability of absolute zero temperature is only a corollary of the Nernst statement or the heat capacity statement so that it is unsuitably referred to as one statement of the third law of thermodynamics. The conclusion is that the Nernst statement and the heat capacity statement are two equivalent statements of the third law of thermodynamics.

关键词： Nernst statement heat capacity statement Nernst theorem absolute zero temperature the third law of thermodynamics

Analysis of pseudo-random number generators in QMC-SSE method

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Chinese physics B 2024年第3期33卷 75-79页

作者：刘东旭徐维张学锋 department of physics Chongqing UniversityChongqing 401331China

In the quantum Monte Carlo(QMC)method,the pseudo-random number generator(PRNG)plays a crucial role in determining the computation ***,the hidden structure of the PRNG may lead to serious issues such as the breakdown of the Markov ***,we systematically analyze the performance of different PRNGs on the widely used QMC method known as the stochastic series expansion(SSE)*** quantitatively compare them,we introduce a quantity called QMC efficiency that can effectively reflect the efficiency of the *** testing several representative observables of the Heisenberg model in one and two dimensions,we recommend the linear congruential generator as the best choice of *** work not only helps improve the performance of the SSE method but also sheds light on the other Markov-chain-based numerical algorithms.

关键词： stochastic series expansion quantum Monte Carlo pseudo-random number generator

Effect of distribution shape on the melting transition, local ordering,and dynamics in a model size-polydisperse two-dimensional fluid

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Chinese physics B 2024年第7期33卷 419-428页

作者： Jackson Pame Lenin SShagolsem department of physics National Institute of Technology ManipurImphalIndia

We study the effect of particle size polydispersity(δ) on the melting transition(T*), local ordering, solid–liquid coexistence phase and dynamics of two-dimensional Lennard–Jones fluids up to moderate polydispersity by means of computer simulations. The particle sizes are drawn at random from the Gaussian(G) and uniform(U) distribution *** these systems, we further consider two different kinds of particles, viz., particles having the same mass irrespective of size, and in the other case the mass of the particle scales with its size. It is observed that with increasing polydispersity,the value of T*initially increases due to improved packing efficiency(φ) followed by a decrease and terminates at δ ≈8%(U-system) and 14%(G-system) with no significant difference for both mass types. The interesting observation is that the particular value at which φ drops suddenly coincides with the peak of the heat capacity(CP) curve, indicating a transition. The quantification of local particle ordering through the hexatic order parameter(Q_6), Voronoi construction and pair correlation function reveals that the ordering decreases with increasing δ and T. Furthermore, the solid–liquid coexistence region for the G-system is shown to be comparatively wider in the T –δ plane phase diagram than that for the U system. Finally, the study of dynamics reveals that polydisperse systems relax faster compared to monodisperse systems;however, no significant qualitative differences, depending on the distribution type and mass polydispersity, are observed.

关键词： polydispersity ordering phase diagram dynamics

Ultrahigh-brightness 50 MeV electron beam generation from laser wakefield acceleration in a weakly nonlinear regime

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Matter and Radiation at Extremes 2024年第3期9卷 4-10页

作者： Zhongtao Xiang Changhai Yu Zhiyong Qin Xuhui Jiao Jiahui Cheng Qiaoxuan Zhou Gatie Axi Jianghua Jie Ya Huang Jintan Cai Jiansheng Liu department of physics Shanghai Normal UniversityShanghai 200234China

We propose an efficient scheme to produce ultrahigh-brightness tens of MeV electron beams by designing a density-tailored plasma to induce a wakefield in the weakly nonlinear regime with a moderate laser energy of 120 *** this scheme,the second bucket of the wakefield can have a much lower phase velocity at the steep plasma density down-ramp than the first bucket and can be exploited to implement longitudinal electron injection at a lower laser intensity,leading to the generation of bright electron beams with ultralow emittance together with low energy ***-dimensional particle-in-cell simulations are carried out and demonstrate that high-quality electron beams with a peak energy of 50 MeV,ultralow emittance of28 nm rad,energy spread of 1%,charge of 4.4 pC,and short duration less than 5 fs can be obtained within a 1-mm-long tailored plasma density,resulting in an ultrahigh six-dimensional brightness B6D,n of2×1017 A/m2/0.1%.By changing the density parameters,tunable bright electron beams with peak energies ranging from 5 to 70 MeV,a small emittance of B0.1 mm mrad,and a low energy spread at a few-percent level can be *** bright MeV-class electron beams have a variety of potential applications,for example,as ultrafast electron probes for diffraction and imaging,in laboratory astrophysics,in coherent radiation source generation,and as injectors for GeV particle accelerators.

关键词： weakly nonlinear acceleration

Tunable luminescence of Bi^(3+)/Eu^(3+)-doped SiO_(2)-Al_(2)O_(3)-MCO_(3)(M=Ca,Sr,Ba) glasses for WLED

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Journal of Rare Earths 2024年第9期42卷 1652-1657,I0001页

作者： Falin Zhang Xiaoying Liang Rongfei Wei Hai Guo Fangfang Hu department of physics Zhejiang Normal UniversityJinhua321004China

In this work,a group of Bi^(3+)/Eu^(3+)-doped SiO2-Al_(2)O_(3)-MCO_(3)(M=Ca,Sr,Ba) glasses were fabricated through melt-quenching *** structure and photoluminescence characters were studied via Xray diffraction(XRD),UV-Vis transmission spectra(TRS),excitation spectra,emission spectra and decay *** XRD results show that no nano-crystal phase forms in glass matrix with different doping concentrations of Bi^(3+)and Eu^(3+)*** regulating optical alkalinity value,the intensity of Bi^(3+)ions increases and the peak position shifts to red *** Bi^(3+)/Eu^(3+) co-doped glasses show a blue-white-yellow-red luminescence by changing concentration of Eu^(3+) *** transfer efficiency from Bi^(3+) to Eu^(3+) can reach as high as 10.54%.At 423 K, the emission intensity of 55SiO_(2)-10Al_(2)O_(3)-35BaO-0.25Bi_(2)O_(3)(GBE0.5) is 31.1% of that at 308 ***,the activation energy of the glass matrix is 0.251 *** results suggest that these Bi^(3+)/Eu^(3+) co-doped glass samples possess potential application in LED field.

关键词： Bi^(3+) Eu^(3+) Glass White light-emitting diode Energy transfer Rare earths

Effect of Eu3+,Bi3+,and Li+ doping on luminescent property of GdNbO4

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Journal of Rare Earths 2024年第1期42卷 66-75页

作者： S.W.Wi Y.S.Lee department of physics and Integrative Institute of Basic Sciences Soongsil University

We investigated the emission properties of Eu3+-doped GdNbO4-based oxide phosphors,aiming at improving the Eu3+emission by codoping of Bi3+and Li+.Eu3+singly doped,Eu3+and Bi3+doubly doped,and Eu3+,Bi3+,and Li+triply doped GdNbO4were prepared using a high-temperature solid-state reaction *** red-orange emissions from Eu3+in the singly doped samples are significantly improved by the codoping of Bi3+,mainly due to the energy transfer from Bi3+to Eu3+.The additional codoping of Li+is found to increase the Eu3+emission *** improvement might be attributed to the increase in the photoluminescent quantum yield originating from larger grain sizes and better crystallinity.A detailed analysis of the X-ray diffraction pattern and the asymmetric ratio estimated from the photoluminescence spectra show that the local lattice environment around Eu3+in GdNbO4does not change significantly with the codoping of Bi3+and Li+.Our results indicate that Li+doping is a promising way to improve the emission properties of rare-earth ion-doped GdNbO4phosphors.

关键词： Eu 3+ GdNbO 4 Codoping of Li + Photoluminescence Sensitizer Rare earths

Nondegenerate Soliton Solutions of(2+1)-Dimensional Multi-Component Maccari System

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Chinese physics Letters 2024年第6期41卷 11-17页

作者：孟勇方乒乒林机 department of physics Zhejiang Normal UniversityJinhua 321004China

For a multi-component Maccari system with two spatial dimensions,nondegenerate one-soliton and two-soliton solutions are obtained with the bilinear *** can be seen by drawing the spatial graphs of nondegenerate solitons that the real component of the system shows a cross-shaped structure,while the two solitons of the complex component show a multi-solitoff *** the same time,the asymptotic analysis of the interaction behavior of the two solitons is conducted,and it is found that under partially nondegenerate conditions,the real and complex components of the system experience elastic collision and inelastic collision,respectively.

关键词： structure. degenerate soliton

Band structures of strained kagome lattices

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Chinese physics B 2024年第2期33卷 456-463页

作者：徐露婷杨帆 Center for Joint Quantum Studies and department of physics School of ScienceTianjin UniversityTianjin 300354China Tianjin Key Laboratory of Low Dimensional Materials physics and Preparing Technology Department of PhysicsTianjin UniversityTianjin 300354China

Materials with kagome lattices have attracted significant research attention due to their nontrivial features in energy *** theoretically investigate the evolution of electronic band structures of kagome lattices in response to uniaxial strain using both a tight-binding model and an antidot model based on a periodic muffin-tin *** is found that the Dirac points move with applied ***,the flat band of unstrained kagome lattices is found to develop into a highly anisotropic shape under a stretching strain along y direction,forming a partially flat band with a region dispersionless along ky direction while dispersive along kx *** results shed light on the possibility of engineering the electronic band structures of kagome materials by mechanical strain.

关键词： kagome lattice strain band structure engineering