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Magnetism of NaYbs_(2):From finite temperatures to ground state

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science China(Physics,Mechanics & Astronomy) 2024年第10期67卷 92-104页

作者： Weizhen zhuo Zheng Zhang Mingtai Xie Anmin Zhang Jianting Ji feng Jin Qingming Zhang school of Physical science and Technology Lanzhou UniversityLanzhou 730000China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Rare-earth chalcogenide compounds ARECh_(2)(A=alkali or monovalent metal,RE=rare earth,Ch=O,s,se,Te)are a large family of quantum spin liquid(QsL)candidate ***2is a representative member of the *** key issues on NaYbs_(2),particularly how to determine the highly anisotropic spin Hamiltonian and describe the magnetism at finite temperatures and the ground state,remain to be *** this paper,we conducted an in-depth and comprehensive study on the magnetism of NaYbs_(2) from finite temperatures to the ground ***,we successfully detected three crystalline electric field(CEF)excitation energy levels using low-temperature Raman scattering *** them with the CEF theory and magnetization data,we worked out the CEF parameters,CEF energy levels,and CEF *** further determined a characteristic temperature of~40 K,above which the magnetism is dominated by CEF excitations while below which the spinexchange interactions play a main *** characteristic temperature has been confirmed by the temperature-dependent electron spin resonance(EsR)***-temperature EsR experiments on the dilute magnetic doped crystal of NaYb_(0.1)Lu_(0.9)s_(2) further helped us to determine the accurate ***,we quantitatively obtained the spin-exchange interactions in the spin Hamiltonian by consistently simulating the magnetization and specific heat ***,the above studies allow us to explore the ground state magnetism of NaYbs_(2) by using the density matrix renormalization *** combined numerical calculations and experimental results to demonstrate that the ground state of NaYbs_(2) is a Dirac-like QsL.

关键词： rare-earth chalcogenide anisotropic spin Hamiltonian quantum spin liquid

In-situ growth of MIL-53(Fe)on charcoal sponge as a highly efficient and recyclable photocatalyst for removal of Cr(Ⅵ)

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Rare Metals 2024年第9期43卷 4344-4355页

作者： zhuo-Fan Yu Ye Yang Hai-feng Zhuang sheng-Dao shan Mihail-simion Beldean-Galea Qing-Quan Xue Xiao-feng shen shi-Jie Li Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province School of Environmental and Natural ResourcesZhejiang University of Science and TechnologyHangzhou 310023China Faculty of Environmental science and Engineering Babes-Bolyai University400294 Cluj-NapocaRomania Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province Interdisciplinary Research Academy(IRA)Zhejiang Shuren UniversityHangzhou 310015China National Engineering Research Center for Marine Aquaculture Institute of Innovation&ApplicationZhejiang Ocean UniversityZhoushan 316022China

The application of metalDorganic frameworks(MOFs)is hindered by several crucial factors,including low photocatalytic efficiency,poor stability and challenges in *** this study,MIL-53(Fe)was grown in situ on a charcoal sponge(Cs)with a large surface area,excellent mechanical properties,and high photocatalytic efficiency using a solvothermal method,thus addressing the above-mentioned shortcomings of MOF ***,Cs/MIL-53(Fe)has an amazing light-harvesting capacity in the visible range,leading to a significant improvement in the utilization of *** results of the experiments indicate that Cs/MIL-53(Fe)displays a higher photocatalytic activity(87%Cr(Ⅵ))when exposed to visible light than Cs(58%)or MIL-53(Fe)(27%),attributing to the increased separation of photogenerated carriers.e-is the main reactive radical and dominates the photocatalytic reduction process,rooting from that e-can reduce Cr(Ⅵ)to low-toxicity Cr(Ⅲ).This study presents a novel method for constructing photocatalysts with large surface areas,superior mechanical characteristics,and enhanced photocatalytic ***,it achieves the resource utilization of agricultural and forestry waste.

关键词： Cr(Ⅵ) Charcoal sponge MIL-53(Fe) Photocatalysis Light absorption

Microstructure and Mechanical Behavior of Mg-Based Bimetal Plates with High Formability sleeve by Co-extrusion

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Acta Metallurgica sinica(English Letters) 2024年第3期37卷 499-512页

作者： Yue-Hui Dang sheng-Lin Liu Xiao-Lei Ai Xiao-Wei feng Bo feng zhuo Tian Ying-Fei Lin Huan-Tao Chen Kai-Hong Zheng school of Materials science and Engineering Chang’an UniversityShaanxi 710064China Guangdong Key Laboratory of Metal Toughening Technology and Application Institute of New MaterialsGuangdong Academy of SciencesGuangzhou 510650China

In this study,microstructure and mechanical behavior of two types of Mg-based bimetal plates with a high formability sleeve were systematically studied,with a great emphasis on the effect of the interface characteristic and the sleeve fraction on the plasticity of composite *** rule of mixtures(ROM)for elongation was also *** results show that when there is no or thin diffusion layer with thickness of about 3μm,Mg-based bimetal plates have a good plasticity with elongation of about 19-24%,and the ROM predicted elongations are very close to the experimental *** contrast,with a diffusion layer about 95-155μm thick,Mg-based bimetal plates exhibit a poor plasticity with elongation of about 11-17%,and the experimental elongations largely deviate from the ROM *** plasticity of Mg-based bimetal plates increases with increasing sleeve *** study provides new insights on the plastic deformation of Mg-based bimetal composites with a high formability sleeve.

关键词： Mg-based composites Co-extrusion Microstructure Mechanical behavior Plastic deformation

symmetry transformation of nonlinear optical current of tilted Weyl nodes and application to ferromagnetic MnBi_(2)Te_(4)

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Chinese Physics B 2024年第4期33卷 160-171页

作者：卢倬成冯济 International Center for Quantum Materials School of PhysicsPeking UniversityBeijing 100871China

A Weyl node is characterized by its chirality and *** develop a theory of how nth-order nonlinear optical conductivity behaves under transformations of anisotropic tensor and tilt, which clarifies how chirality-dependent and-independent parts of optical conductivity transform under the reversal of tilt and *** on this theory, we propose ferromagnetic Mn Bi2Te4as a magnetoelectrically regulated, terahertz optical device, by magnetoelectrically switching the chiralitydependent and-independent DC *** results are useful for creating nonlinear optical devices based on the topological Weyl semimetals.

关键词： nonlinear optical response topological Weyl semimetals chiral anomaly

Berry-Esseen bounds for self-normalized sums of locally dependent random variables

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science China Mathematics 2024年第11期67卷 2629-2652页

作者： zhuo-song Zhang Department of statistics and Data science Southern University of Science and Technology

The Berry-Esseen bound provides an upper bound on the Kolmogorov distance between a random variable and the normal *** this paper,we establish Berry-Esseen bounds with optimal rates for self-normalized sums of locally dependent random variables,assuming only a second-moment *** proof leverages stein's method and introduces a novel randomized concentration inequality,which may also be of independent interest for other *** main results have applied to self-normalized sums of m-dependent random variables and graph dependency models.

关键词： Berry-Esseen bounds self-normalized sums localdependence $m$-dependence graph dependency

Energy beam-based direct and assisted polishing techniques for diamond:A review

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International Journal of Extreme Manufacturing 2024年第1期6卷 93-124页

作者： zhuo Li feng Jiang Zhengyi Jiang Zige Tian Tian Qiu Tao Zhang Qiuling Wen Xizhao Lu Jing Lu Hui Huang Institute of Manufacturing Engineering Huaqiao UniversityXiamen 361021People’s Republic of China school of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW 2522Australia College of Mechanical Engineering and Automation Huaqiao UniversityXiamen 361021People’s Republic of China state Key Laboratory of High Performance Tools Huaqiao UniversityXiamen 361021People’s Republic of China

Diamond is a highly valuable material with diverse industrial applications,particularly in the fields of semiconductor,optics,and high-power ***,its high hardness and chemical stability make it difficult to realize high-efficiency and ultra-low damage machining of *** address these challenges,several polishing methods have been developed for both single crystal diamond(sCD)and polycrystalline diamond(PCD),including mechanical,chemical,laser,and ion beam processing *** this review,the characteristics and application scope of various polishing technologies for sCD and PCD are ***,various energy beam-based direct and assisted polishing technologies,such as laser polishing,ion beam polishing,plasma-assisted polishing,and laser-assisted polishing,are *** current research progress,material removal mechanism,and infuencing factors of each polishing technology are *** some of these methods can achieve high material removal rates or reduce surface roughness,no single method can meet all the ***,the future development prospects and application directions of different polishing technologies are presented.

关键词： single crystal diamond polycrystalline diamond energy beam polishing technology material removal mechanism influencing factors

Achieving a remarkable low-temperature tensile ductility in a high-strength tungsten alloy

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Tungsten 2024年第1期6卷 150-161页

作者： Xiang Cheng zhuo-Ming Xie Xue-feng Xie Long-Fei Zeng Rui Liu Jun-feng Yang Xue-Bang Wu Xian-Ping Wang Chang-song Liu Qiang-feng Fang Key Laboratory of Materials Physics Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031China University of science and Technology of China Hefei 230026China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China

Hot-swaging yields a high ultimate tensile strength of 712 MPa but a limited tensile ductility with the total elongation of3.6%at a testing temperature of 200℃in a representative W-0.5wt.%ZrC *** this work,the evolution of Vickers microhardness with annealing temperatures is investigated in detail,which contributes to a rough index chart to guide the search for an optimized post-annealing *** the post-annealing around 1300℃,an outstanding tensile ductility at200℃,including a uniform elongation of 14%and a total elongation of~25%,has been achieved without the sacrifice of its *** evolution of dislocations and grain structures with the annealing temperatures accessed through backscattered scanning electron microscope and transmission electron microscope analysis reveals that the improved low-temperature tensile ductility has resulted from the reduction of residual dislocations and dislocation tanglement via the static recovery,which provides more room to accommodate dislocations,and hence stronger strain hardening ability and tensile ductility.

关键词： Tungsten Low-temperature ductility Annealing Dislocations

Relative Broken Family sensitivity

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Acta Mathematica sinica,English series 2024年第9期40卷 2297-2306页

作者： zhuo Wei LIU Tao YU Department of Mathematics Shantou UniversityShantou 515063P.R.China

Letπ:(X,T)→(Y,s)be a factor map between two topological dynamical systems,and F_(a) Furstenberg family of *** introduce the notion of relative broken *** Fs(***,Finf)be the families consisting of all syndetic subsets(*** upper Banach density subsets,infinite subsets).We show that for a factor mapπ:(X,T)→(Y,s)between transitive systems,πis relatively broken F-sensitive for F=Fs or Fpubd if and only if there exists a relative sensitive pair which is an F-recurrent point of(R_(π),T^((2)));is relatively broken Finf-sensitive if and only if there exists a relative sensitive pair which is not *** a factor mapπ:(X,T)→(Y,s)between minimal systems,we get the structure of relative broken F-sensitivity by the factor map to its maximal equicontinuous factor.

关键词： Relative sensitivity recurrent points Furstenberg family relative sensitive pairs maximal equicontinuous factor

Enrichment of Chemical Element ^(7)Li in the Rotating Red Clump star

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Chinese Physics Letters 2024年第8期41卷 121-125页

作者： Fang-Wen Wu Han-feng song Qing-Li Li Yun He Xin-Yue Qu zhuo Han College of Physics Guizhou UniversityGuiyang 550025China Geneva Observatory University of GenevaCH-1290 SauvernySwitzerland

About 2 percent of red clump stars are found to be the lithium-rich and thus the surface lithium increases obviously in some red clump *** physical mechanism of the lithium enrichment in these stars has not yet been explained satisfactorily by the evolutionary models of single *** flash induced internal gravity wave mixing(i.e.,IGW)could play a primary role in explaining the red clump star with lithium enrichment and it has a very significant impact on the internal structure and surface compositions of a *** can significantly increase the mixing efficiency of the internal gravity wave because the timescale for the enrichment event has been *** mixing can explain the observed behavior of lithium on red giant stars that are more luminosity than the RGB ***,it has a very small effect on the diffusion of elements because its diffusion coefficient is much smaller than the one of IGW induced mixing after the core helium flash.

关键词： flash stars lithium