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Deformation and mutual influence of two cylindrical water columns in tandem subjected to shock wave

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Chinese physics B 2024年第8期33卷 316-327页

作者：洪振宇宋洋王睿马宗强马东军王裴 institute of Applied physics and Computational Mathematics Beijing 100094China Graduate School of China Academy of Engineering physics Beijing 100088China Center for Applied physics and Technology Peking UniversityBeijing 100871China

The interaction between shock waves and multiple cylinders,referred to as shock–cylinder interaction(SCI),is an important phenomenon in science and ***,its underlying physical mechanisms remain *** study entailed the numerical simulation of the aerobreakup of two tandem water columns subjected to a high-speed gas flow by using an adaptive mesh refinement(AMR)-based diffusion-interface *** objective was to elucidate the changes in water–column deformation patterns over a wide range of Weber *** analysis was performed to examine the deformation of the water columns in vertical *** reveal distinct deformation patterns between the two columns as the Weber number ***,an extended exponential stretching law model was devised,and its improved capability to predict the deformation patterns was demonstrated.

关键词： shock-cylinder interaction(SCI) Weber number effect aerobreakup multiphase flow

Tensor perturbations from bounce inflation scenario in f(Q)gravity

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Science China(physics,Mechanics & Astronomy) 2024年第2期67卷 78-92页

作者： Kun Hu Tanmoy Paul Taotao Qiu institute of Astrophysics Central China Normal UniversityWuhan 430079China School of physics Huazhong University of Science and TechnologyWuhan 430074China National institute of Technology Jamshedpur Department of PhysicsJamshedpur 831014India

In this paper,we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity,namely f(Q)theory,and investigate the tensor perturbations *** is well-known,the tensor perturbations generated in the very early Universe(inflation and pre-inflation regions)can account for the primordial gravitational waves(PGWs)that are to be detected by the next generation of GW *** discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation *** general form of the tensor power spectrum is obtained both for large as well as small scale *** a result,we show both kinds of modes(short or long wavelength modes),and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves’amplitude in the background of the f(Q)bounce-inflation ***,we study the LQC-like scenario as a specific case of our model,in which,the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales.

关键词： bounce cosmology modified gravity cosmological perturbations

Effect of trace oxygen on plasma nitriding of titanium foil

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Chinese physics B 2024年第6期33卷 548-551页

作者：周海涛熊希雅马可欣罗炳威罗飞申承民 Beijing institute of Aeronautical Materials Aero Engine Corporation of ChinaBeijing 100095China Beijing National Laboratory of Condensed Matter physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Titanium nitride films are prepared by plasma enhanced chemical vapor deposition method on titanium foil using N_(2) as precursor. In order to evaluate the effect of oxygen on the growth of titanium nitride films, a small amount of O_(2) is introduced into the preparation process. The study indicates that trace O_(2) addition into the reaction chamber gives rise to significant changes on the color and micro-morphology of the foil, featuring dense and long nano-wires. The as-synthesized nanostructures are characterized by various methods and identified as TiN, Ti_(2) N, and TiO_(2) respectively. Moreover, the experiment results show that oxide nanowire has a high degree of crystallinity and the nitrides present specific orientation relationships with the titanium matrix.

关键词： nitride oxide nanostructure crystalline plasma-enhanced chemical vapor deposition system(PECVD)

Pressure-Driven Energy Band Gap Narrowing of λ-N_(2)

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Chinese physics Letters 2024年第4期41卷 173-177页

作者：李月刘静仪吴彬彬陶雨耿延雷王晓丽雷力 institute of Atomic and Molecular physics Sichuan UniversityChengdu 610065China School of physics and Electronic Information Yantai UniversityYantai 264005China

Probing the energy band gap of solid nitrogen at high pressures is of importance for understanding pressuredriven changes in electronic structures and insulator-to-metal transitions under high *** λ-N_(2) formed by cold compression is known to be the most stable one in all solid nitrogen phases observed so *** optimizing the optical system,we successfully measured the high-pressure absorption spectra of λ-N_(2) covering the polymericnitrogen synthetic pressures(124 GPa-165 GPa).The measured optical band gap decreases with increasing pressure,from 2.23 eV at 124 GPa to 1.55 eV at 165 GPa,with a negative pressure coefficient of-18.4 meV/GPa,which is consistent with the result from our ab initio total-energy calculations(-22.6 meV/GPa).The extrapolative metallization pressure for theλ-N_(2) is around 288(18)GPa,which is close to the metallization pressure(280 GPa)for the η-N_(2) expected by previous absorption edge and direct electrical *** results provide a direct spectroscopic evidence for the pressure-driven band gap narrowing of solid nitrogen.

关键词： absorption transitions spectroscopic

Strong-coupling superconductivity with Tc above 70 K in Be-decorated monolayer T-graphene

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Science China(physics,Mechanics & Astronomy) 2024年第1期67卷 99-105页

作者： Liu Yang Peng-Fei Liu Hao-Dong Liu Ya-Ping Li Na Jiao Hong-Yan Lu Bao-Tian Wang Ping Zhang School of physics and Physical Engineering Qufu Normal UniversityQufu 273165China institute of High Energy physics Chinese Academy of SciencesBeijing 100049China Spallation Neutron Source Science Center Dongguan 523803China institute of Applied physics and Computational Mathematics Beijing 100088China

Using first-principles calculations,we predict a new type of two-dimensional(2D)beryllium(Be)-decorated T-graphene named BeC_(2),where Be atoms are inserted into C–C bonds linking the carbon tetrarings of *** band structure shows that BeC_(2)is metallic,thus,the possible phonon-mediated superconductivity is explored based on the Eliashberg *** calculated electron-phonon coupling(EPC)constantλis up to 4.07,and the corresponding superconducting critical temperature(Tc)is 72.1 K,approaching the liquid nitrogen *** reason for the high Tc is the strong *** it is proved to be an anisotropic single-gap superconductor by analyzing the superconducting gap?kof BeC_(2).The electronic susceptibility calculation shows strong nesting effect in BeC_(2).Since rare 2D superconductors show such a strong EPC constantλwhich originates from the coupling between electrons in C-pzorbital and in-plane vibrations of Be and C atoms,the predicted BeC_(2)provides a new platform for investigating strong EPC 2D superconductor.

关键词： two-dimensional carbon-based superconductor electron-phonon coupling strong coupling high superconducting critical temperature

Design of a 3D-printed liquid lithium divertor target plate and its interaction with high-density plasma

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Plasma Science and Technology 2024年第8期26卷 112-120页

作者：苑聪聪叶宗标刘建星郭恒鑫彭怡超廖加术陈波陈建军王宏彬韦建军张秀杰芶富均 institute of Nuclear Science and Technology Sichuan UniversityChengdu 610064People’s Republic of China institute of Atomic and Molecular physics Sichuan UniversityChengdu 610064People’s Republic of China Southwestern institute of physics Chengdu 610064People’s Republic of China

A liquid Li divertor is a promising alternative for future fusion *** this work a new divertor model is proposed,which is processed by 3D-printing technology to accurately control the size of the internal capillary *** a steady-state heat load of 10 MW m^(-2),the thermal stress of the tungsten target is within the bearing range of tungsten by finite-element *** order to evaluate the wicking ability of the capillary structure,the wicking process at 600℃ was simulated by *** result was identical to that of the corresponding *** 1 s,liquid lithium was wicked to the target surface by the capillary structure of the target and quickly spread on the target *** the wicking process,the average wicking mass rate of lithium should reach 0.062 g s^(-1),which could even supplement the evaporation requirement of liquid lithium under an environment>950℃.Irradiation experiments under different plasma discharge currents were carried out in a linear plasma device(SCU-PSI),and the evolution of the vapor cloud during plasma irradiation was *** was found that the target temperature tends to plateau despite the gradually increased input current,indicating that the vapor shielding effect is gradually *** irradiation experiment also confirmed that the 3D-printed tungsten structure has better heat consumption performance than a tungsten mesh structure or multichannel *** results reveal the application potential and feasibility of a 3D-printed porous capillary structure in plasma-facing components and provide a reference for further liquid-solid combined target designs.

关键词： fusion divertor 3D-printing tungsten lithium liquid metal

Masses and decays of triply-heavy pentaquarks

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Chinese physics C 2024年第10期48卷 137-149页

作者： Chang-Le Liu Wen-Xuan Zhang Duo-Jie Jia institute of Theoretical physics College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070China General Education Center Qinghai Institute of TechnologyXining 810000China Lanzhou Center for Theoretical physics Lanzhou UniversityLanzhou 730000China

In this study,we analyzed masses and decays of triply-heavy pentaquarks QQQnn(Q=b,c)in the unified MIT bag *** construct the color-spin wave functions of the triply-heavy pentaquarks and use the numerical variational method to compute all the ground-state masses of these *** excluding the scattering states in configuration spsce,we computed the decay width ratios of each decay channel relative to the maximum width for the compact pentaquark states,obtaining the main decay modes of the triply-heavy pentaquark systems.

关键词： pentaquark mass decay channels

Intrinsic valley-polarized quantum anomalous Hall effect in a two-dimensional germanene/MnI_(2) van der Waals heterostructure

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Chinese physics B 2024年第7期33卷 2-7页

作者：董晓晶张昌文 School of physics and Technology Institute of SpintronicsUniversity of JinanJinan 250022China School of physics and Physical Engineering Qufu Normal UniversityQufu 273100China

Valley-polarized quantum anomalous Hall effect(VQAHE), combined nontrivial band topology with valleytronics,is of importance for both fundamental sciences and emerging applications. However, the experimental realization of this property is challenging. Here, by using first-principles calculations and modal analysis, we predict a mechanism of producing VQAHE in two-dimensional ferromagnetic van der Waals germanene/MnI_(2) heterostructure. This heterostructure exhibits both valley anomalous Hall effect and VQAHE due to the joint effects of magnetic exchange effect and spin–orbital coupling with the aid of anomalous Hall conductance and chiral edge state. Moreover interestingly, through the electrical modulation of ferroelectric polarization state in In_(2)Se_(3), the germanene/Mn I_(2)/In_(2)Se_(3) heterostructure can undergo reversible switching from a semiconductor to a metallic behavior. This work offers a guiding advancement for searching for VQAHE in ferromagnetic van der Waals heterostructures and exploiting energy-efficient devices based on the VQAHE.

关键词： valley-polarized quantum anomalous Hall effect ferromagnetic

C-Type Antiferromagnetic Structure of Topological Semimetal CaMnSb2

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Chinese physics Letters 2024年第03期41卷 119-125页

作者：李博曾旭涛徐千惠杨帆项俊森钟恒扬邓司浩何伦华徐菊萍殷雯鲁兴业刘慧颖胜献雷金文涛 School of physics Beihang University Beijing National Laboratory for Condensed Matter physics and Institute of PhysicsChinese Academy of Sciences Center for Advanced Quantum Studies and Department of physics Beijing Normal University Spallation Neutron Source Science Center Songshan Lake Materials Laboratory

Determination of the magnetic structure and confirmation of the presence or absence of inversion （P） and time reversal （Τ） symmetry is imperative for correctly understanding the topological magnetic materials. He... 详细信息

关键词： Density functional theory