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Tunable vortex radiation source driven by free electrons

Optics Letters 2025年第10期50卷 3333-3336页

作者： Li, Sirui Li, Tianyi Sun, Jingbo Wen, Yongzheng Zhou, Ji State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing100084 China State Key Laboratory of Nuclear Physics and Technology Institute of Heavy Ion Physics School of Physics Peking University Beijing100871 China

In this Letter, we propose a scheme to generate tunable vortex radiation through the interaction of free electrons with a dual-layer metasurface. The metasurface combines a field-enhancement layer with a phase-modulation layer to produce enhanced Smith–Purcell radiation (SPR) while enabling gradient phase control. This configuration efficiently converts the free-electron evanescent field into a coherent vortex beam. Simulation results indicate that the proposed structure generates coherent radiation with approximately 4.5 times the intensity of conventional vortex radiation under identical electron-beam conditions. The frequency and direction of the vortex radiation can be tuned by varying the electron velocity. Moreover, the structure enables coherent vortex radiation generation with a small number of electrons, including low-velocity electrons, without requiring strong focusing magnetic fields or periodic electron bunching. This work establishes an innovative approach for developing compact, efficient, and tunable vortex radiation sources based on free electrons. © 2025 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.

关键词： Particle beam bunching

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Wess-Zumino-Witten Interactions of Axions

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Physical Review Letters 2025年第8期134卷 081803-081803页

作者： Yang Bai Ting-Kuo Chen Jia Liu Xiaolin Ma Department of Physics University of Wisconsin-Madison Madison Wisconsin 53706 USA School of Physics and State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China Center for High Energy Physics Peking University Beijing 100871 China

We present a consistent derivation of the complete Wess-Zumino-Witten interactions of axions, including the counter-term necessary to guarantee the gauge invariance of the standard model. By treating the derivative of the axion field as a background gauge field and incorporating auxiliary chiral rotation phases, we ensure consistency in the axion-interaction Lagrangian. This approach allows us to derive basis-independent physical interactions of axions with gauge bosons and vector mesons. These interactions have broad applications in axion phenomenology for both light and heavy axion particles.

关键词： Bosons

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Recent progress on photoactive nonprecious transition-metal complexes

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Science China Chemistry 2025年第1期68卷 46-95页

作者： Zhong-Liang Gong Hong-Jie Zhang Yan Cheng Jianxun Liu Yuhan Ai Yaqin Li Zhihui Feng Qiong Zhang Shaolong Gong Yong Chen Chang-Jiang Yao Yuan-Yuan Zhu Liang-Jin Xu Yu-Wu Zhong CAS Key Laboratory of Photochemistry Institute of ChemistryChinese Academy of SciencesBeijing 100190China State Key Laboratory of Structural Cemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China School of Chemistry and Chemical Engineering Anhui Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of TechnologyHefei 230009China State Key Laboratory of Explosion Science and Safety Protection School of Mechatronical EngineeringBeijing Institute of TechnologyBeijing 100081China College of Chemistry and Molecular Sciences Hubei Key Lab on Organic and Polymeric Optoelectronic MaterialsWuhan UniversityWuhan 430072China School of Chemistry and Chemical Engineering Anhui UniversityHefei 230601China Key Laboratory of Photochemical Conversion and Optoelectronic Materials&CAS-HKU Joint Laboratory on New Materials Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China

Photoactive complexes of nonprecious transition metals,mainly including those in the first-row and partially the second-row of the Periodic table of elements,have received increasing attention in view of their low cost and long-term *** are recognized as promising alternatives to noble transition metal complex congeners that have been extensively studied in optoelectronic devices,artificial photosynthesis,photocatalysis,biodiagnostics,and therapeutics,*** review is devoted to a comprehensive summary on the classical and recent advances on photoactive nonprecious transition metal complexes,including photoactive Zr,V,Cr,Mo,and W complexes,Mn complexes and hybrids,Fe,Co,Ni,and Cu complexes,and Zn and Cd complexes and hybrids.A particular focus is given on the molecular design,modulation of photophysical and photochemical properties,and applications of the representative and lately-developed nonprecious metal *** addition,a perspective on the future development in this field is provided at the end of this review.

关键词： photoactive metal complexes earth-abundant metals nonprecious metal complexes luminescence photochemistry

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Predictions of H-mode access and edge pedestal instability in the EHL-2 spherical torus

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Plasma Science and technology 2025年第2期27卷 54-63页

作者： Yumin WANG Kai LI Zhuo HUANG Yiliang LIU Shuyu DAI Jie ZHANG Yanqing HUANG Xiang GU Yihang ZHAO Shuai XU Erhui WANG Dong GUO Yuejiang SHI Huasheng XIE Yunfeng LIANG Minsheng LIU the EHL-2 Team Hebei Key Laboratory of Compact Fusion Langfang 065001People’s Republic of China ENN Science and Technology Development Co. Ltd.Langfang 065001People’s Republic of China Centre for Theoretical and Computational Physics College of PhysicsQingdao UniversityQingdao 266071People’s Republic of China College of Computer Science South-Central Minzu UniversityWuhan 430074People’s Republic of China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Department of Plasma Physics and Fusion Engineering University of Science and Technology of ChinaHefei 230026People’s Republic of China College of Physics and Electronic Engineering Hengyang Normal UniversityHenyang 421002People’s Republic of China Forschungszentrum Jülich GmbH Institute of Fusion Energy and Nuclear Waste Management-PlasmaphysikJülich 52425Germany

The EHL-2 spherical torus is designed to demonstrate proton-boron(p-11B)fusion within a compact spherical *** planned heating system includes a negative ion-based neutral beam injection(N-NBI),two positive ion-based NBI systems(P-NBI),electron cyclotron resonance heating(ECRH),ion cyclotron resonance heating(ICRH),and high harmonic fast wave(HHFW),with a total power output of 31 *** to scaling law estimates,the device is capable of achieving H-mode *** plasma density,,n_(e,min)at the minimum L-H power threshold,P_(lh),is estimated to be 4.4×10^(19)m^(-3).The pedestal parameters were calculated using the REPED *** B as the primary impurity ion,the predicted pedestal width and height are lower compared to the typical case with carbon *** pedestal collisionality for EHL-2 is estimated to range between 0.06 and 0.17,indicating the potential for significant energy loss due to edge localized modes(ELMs).The heat flux on the divertor plate has been calculated using the JOREK *** peak heat fluxes during ELM bursts are approximately 31.0 MW/m^(2)at the lower inboard target and 39.5 MW/m^(2)at the lower outboard target.A preliminary design of the resonant magnetic perturbation(RMP)coils has been completed to both control type-I ELMs and correct error *** system comprises 16 coils arranged into 24 *** ELM control mode,a 14/2 component is generated at 1.7 G/kAt,with a current of 4.9 kA required to achieveσChirikow=1 at the resonant surface,where the normalized poloidal magnetic flux is *** error field(EF)modulation mode,2/1 and 3/1 components are generated at 3.5 G/kAt and 2.8 G/kAt,respectively.

关键词： H-mode spherical torus(ST) EHL-2 pedestal resonant magnetic perturbations

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Transport analysis of the EHL-2 spherical torus in a high-ion-temperature scenario

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Plasma Science and technology 2025年第2期27卷 75-86页

作者： Xueyun WANG Wenjun LIU Danke YANG Guang YANG Muzhi TAN Xinchen JIANG Huasheng XIE Yuejiang SHI Hanyue ZHAO Yumin WANG Yunfeng LIANG Jiaqi DONG Bin WU Chengyue LIU the EHL-2 Team Hebei Key Laboratory of Compact Fusion Langfang 065001People’s Republic of China ENN Science and Technology Development Co. Ltd.Langfang 065001People’s Republic of China Forschungszentrum Jülich GmbH Institute of Fusion Energy and Nuclear Waste Management-PlasmaphysikJülich 52425Germany Southwestern Institute of Physics Chengdu 610225People’s Republic of China Institute of Plasma Physics Chinese Academy of SciencesHefei 230026People’s Republic of China School of Physics Hefei University of TechnologyHefei 230009People’s Republic of China

EHL-2 is an ENN second-generation device aimed at studying proton-boron(p-11B)fusion reactions in a spherical *** design parameters are Ti0~30 keV,Ti/Te>2,n_(e0)~1×10^(20)m^(-3),I_(p)~3 MA,B_(t)~3 T,andτ_(E)~0.5 *** ion temperature is one of the standard operation scenarios of EHL-2,aiming to reduce bremsstrahlung radiation while enhancing plasma parameters by elevating the ion to electron temperature *** order to achieve high ion temperature,neutral beam injection is considered the primary heating method during the flat-top *** neutral beam system for EHL-2 comprises 3-5 beams with energy/power ranging from 60 keV/4 MW,80-100 keV/10 MW,to 200 keV/3 *** work conducts predictive analysis on core transport during the flat-top phase of EHL-2’s high-ion-temperature scenario utilizing *** study delineates the potential operating range of core temperature and other parameters given the designed heating ***,the study presents predictive simulations based on CDBM,GLF23,Bohm-gyro-Bohm,and IFSPPPL transport models,evaluating the steady-state power balance,energy confinement time,and impact of various parameters such as plasma density and NBI power on core ion *** simulations demonstrate that the design parameters of the EHL-2 high-Ti scenario,although sensitive to varying transport models,are hopefully attainable as long as adequate ion heating and controlled ion transport levels are ensured.

关键词： transport ASTRA hot-ion mode spherical torus

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Analysis for the nonlinear primary resonance behavior and bifurcation characteristics of the hydrostatic spindle

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Nonlinear Dynamics 2025年 1-24页

作者： Zhang, Han Wen Rong, You Min Cui, Hai Long Hu, Hai Dong Huang, Yu State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan430074 China School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan430074 China Guangdong Provincial Key Laboratory of Manufacturing Equipment Digitization Guangdong HUST Industrial Technology Research Institute Dongguan China Institute of Machinery Manufacturing Technology China Academy of Engineering Physics Mianyang621000 China

In order to effectively reduce or avoid the abnormal vibration of the hydrostatic spindle caused by the nonlinear oil film force, it is particularly important to grasp the vibration behavior mechanism. Therefore, the analytical mechanics combined with the elastic mechanics method-assumed modal method is applied to establish the nonlinear dynamics model and the average method is introduced to solve the amplitude-frequency response equation of the primary resonance. Based on amplitude-frequency response equations and singularity theory, a transfer-set root-finding algorithm is proposed to solve the primary resonance bifurcation boundary solution problem of the amplitude-frequency and parameter coupling system. The correctness of the dynamics model and the average solution results are verified by experiments. The effects of spindle stiffness, excitation force and oil film gap on the nonlinear primary resonance behavior of hydrostatic spindle and the bifurcation characteristics of the two-parameter variables are investigated. The results show that: due to the nonlinearity of the supporting oil film force, the nonlinear primary resonance behaviors of oil film oscillation phenomenon, jump phenomenon, multi-solution phenomenon, unstable solution and whirl will appear in the range of dimensionless frequency ratios w = [0.6, 0.8]. The spindle stiffness suppresses the nonlinear phenomena, the excitation force and oil film gap promote the nonlinear phenomena. When the structural parameter combination points fall within the range of the root-finding algorithm of the transfer set, there will be different degrees of bifurcated nonlinear dynamic behavior, and when the structural parameter combination points fall outside, there is basically no nonlinear dynamic behavior. © The Author(s), under exclusive licence to Springer Nature B.V. 2025.

关键词： Bifurcation (mathematics)

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Positron annihilation study of defect formation and evolution in matrix graphite under He ion irradiation

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nuclear Science and Techniques 2025年第1期36卷 13-21页

作者： Hong-Xia Xu Jian-Dang Liu Bang-Jiao Ye Zi-Wen Pan Jun Lin Jin-Liang Song Jian-Qing Cao Chao Yan Ying-Ping Hao Jin-Xing Cheng Qing-Bo Wang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China State Key Laboratory of Particle Detection and Electronics University of Science and Technology of ChinaHefei 230026China Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine Shanghai 200025China Beijing Institute of High Technology Beijing 100094China

The stability of matrix graphite under neutron irradiation and in corrosive environments is crucial for the safe operation of molten salt reactors(MSRs).Raman spectroscopy and a slow positron beam were employed to investigate the effects of He ion irradiation fluences and subsequent annealing on the microstructure and defects of the matrix *** ions with 500 keV energy and fluences ranging from 1.1×10^(15)ions∕cm^(2)to 3.5×10^(17)ions∕cm^(2)were used to simulate neutron irradiation at 300 *** samples with an irradiation fluence of 3.5×10^(16)ions∕cm^(2)were subjected to isochronal annealing at different temperatures(573 K,873 K and 1173 K)for 3 *** Raman results revealed that the D peak gradually increased,whereas the intrinsic G peak decreased with increasing irradiation *** the same irradiation fluence,the D peak gradually decreased,whereas the intrinsic G peak increased with increasing annealing *** positron beam analysis demonstrated that the density or size of irradiation defects(vacancy type)increased with higher irradiation fluence,but decreased rapidly with increasing annealing *** Raman spectral analysis of sample cross sections subjected to high irradiation fluences revealed the emergence of amorphization precisely at the depth where ion damage was most pronounced,whereas the surface retained its crystalline *** and positron annihilation analyses indicated that the matrix graphite exhibited good irradiation resistance to He ions at 300 ***,vacancy-type defects induced by He ion irradiation exhibit poor thermal stability and can be easily removed during annealing.

关键词： Graphite Positron annihilation Irradiation Raman spectrum

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Tests of CP Symmetry in Entangled Hyperon Antihyperon Pairs at BESⅢ

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Chinese physics Letters 2025年第4期42卷 38-42页

作者： Wenjing Zheng Andrzej Kupsc Simone Pacetti Francesco Rosini Nora Salone Xiongfei Wang Shuang-shi Fang Institute of High Energy Physics Chinese Academy of SciencesBeijing100049China University of Chinese Academy of Sciences Beijing100049China Department of Physics and Astronomy Uppsala UniversityBox516SE-75120UppsalaSweden National Centre for Nuclear Research Pasteura 702-093 WarsawPoland INFN Sezione di Perugia 06100 PerugiaItaly Universitàdi Perugia 06100 PerugiaItaly University of Silesia in Katowice Institute of Physics75 Pulku Piechoty 141-500 ChorzowPoland School of Physical Science and Technology Lanzhou UniversityLanzhou 730000China Lanzhou Center for Theoretical Physics Key Laboratory of Theoretical Physics of Gansu ProvinceKey Laboratory of Quantum Theory and Applications of MoEGansu Provincial Research Center for Basic Disciplines of Quantum PhysicsLanzhou UniversityLanzhou 730000China Institute of Physics Henan Academy of SciencesZhengzhou 450046China

Decays of charmonium into hyperon and antihyperon pairs provide a pristine laboratory for exploring hyperon properties,such as their polarization and decay parameters,and for conducting tests of fundamental *** brief review highlights the significant progress made in precise tests of CP symmetry at BESIII using entangled hyperon-antihyperon pairs。

关键词： BESIII hyperon antihyperon pairs tests cp symmetry decay parameters CP symmetry decays charmonium hyperon antihyperon pairs polarization exploring hyperon

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Experimental demonstration of single-spin Stirling engine cycles with enhanced efficiency

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Physical Review A 2025年第1期111卷 L010203-L010203页

作者： P.-D. Li G.-Y. Ding J.-Q. Zhang Q. Yuan S.-Q. Dai T.-H. Cui F. Zhou L. Chen Q. Zhong State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and Mathematics Innovation Academy of Precision Measurement Science and Technology Chinese Academy of Sciences Wuhan 430071 China School of Physics University of the Chinese Academy of Sciences Beijing 100049 China Research Center for Quantum Precision Measurement Guangzhou Institute of Industry Co. Ltd Guangzhou 511458 China Department of Engineering Science and Mechanics and Materials Research Institute Pennsylvania State University University Park State College Pennsylvania 16802 USA

Quantum heat engines (QHEs) employing Otto, Carnot, and Szilard cycles have already been demonstrated. Experimental demonstration of the quantum Stirling engine has been hindered due to the challenges in realizing a quantum isothermal process with qubits. Here, we experimentally execute a single-ion Stirling QHE and demonstrate that its efficiency is enhanced when dephasing is involved during the heat release strokes, which is contrary to the conventional viewpoint that dephasing deteriorates quantum features, resulting in reduced performance in QHEs. We also observe periodic oscillations in the heat absorption and the efficiency of the Stirling QHE, indicating the involvement of quantum coherence in the engine cycles. Our experiment is the first execution of Stirling QHE in a spin system, which may help better understand quantum thermodynamics and open new possibilities toward harnessing decoherence as a resource to improve the performance of QHEs.

关键词： Stirling engines

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Study on the Friction and Wear Performance of Graphene/Porous Bronze Composites

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Journal of Tribology 2025年第8期147卷 081402页

作者： Xu, Jin Zhang, Zheyuan Qiao, Zhijun Zhang, Xiaofeng Zhu, Fuan School of Mechanical Engineering Tianjin University Tianjin300350 China State Key Laboratory of Luminescence Science and Technology Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences Changchun130033 China School of Mechanical Engineering Tiangong University Tianjin300387 China

The porous surface of air bearings may suffer from surface scratching and wear issues during the start-stop processes or under extreme working conditions. To improve the lubrication performance and service life of the porous restrictors, this study combined powder metallurgy and chemical vapor deposition to fabricate graphene/porous bronze composites. On this basis, the friction and wear properties of porous composites were investigated. The prepared porous composites and the friction surfaces were described by various means such as coefficient of friction (COF), morphology scanning, surface roughness, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Moreover, during the composite fabrication, the flowrates of carbon sources were set to be 3, 6, 9, and 12 sccm, respectively, to investigate the effect of graphene content on the lubrication performance of the original porous matrix. In the experiments, the lubricating performance of the composite was optimized at a flowrate of 12 sccm. Compared to the original porous bronze, the COF was decreased by 8.4% and the wear-rate by 10.5%. Furthermore, the research findings indicated that the grown graphene also affects the sintering process of the porous matrix, leading to weak connections between powders and differences in the final pore structure. Thus, the final pore structure, along with the presence of graphene, jointly influences the lubrication performance of the porous composites. © 2024 by ASME.

关键词： Sintering

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