The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect require...The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.展开更多
Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapi...Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapid,contactless,and environmentally benign operation,has emerged as a promising approach for precise liquid control.However,conventional magnetic strategies typically govern droplet movement on open surfaces,facing limitations such as restricted liquid volumes,uncertain flow paths,and inevitable evaporation,thereby constraining their broader practical applications.Recently,a variety of magneticdriven strategies have been developed to dynamically regulate liquids within enclosed spaces,especially through physicochemical mechanisms.These approaches provide efficient control over liquid behavior by leveraging magnetically induced chemical changes,structural deformations,and dragging motions,opening new opportunities for flexible and versatile fluid management.This review explores the design and mechanisms of magneto-responsive confined interfaces for the manipulation of nonmagnetic liquids,highlighting key advancements and potential applications including liquid valves,liquid mixing,liquid flow regulation,and liquid pumping.Finally,the existing challenges and future prospects in this field are presented.展开更多
The utilization of nanostructures with diverse geometric shapes is essential for manipulating the energy of electromagnetic(EM) fields and achieving various applications in optics, such as nanofocusing. The plasmonic ...The utilization of nanostructures with diverse geometric shapes is essential for manipulating the energy of electromagnetic(EM) fields and achieving various applications in optics, such as nanofocusing. The plasmonic cone structure is highly representative in the field of nanofocusing applications, effectively guiding EM field energy to the tip of the cone and resulting in high local electric field and temperature effects. In certain chemical catalytic applications, an elevated temperature and a larger surface area may be required to enhance catalysis reactions. Here, we propose a hollow gold nanocone structure that can achieve higher temperature both at the tip and within its hollow region under the excitation of an EM field.Through rigorous finite element method(FEM) simulations, we investigated the EM field and temperature distribution of the hollow cone at various cone angles and identified those angles that yield higher local temperatures. Additionally, the analysis of the scattering cross section of hollow cones reveals that the presence of electric dipole component of the EM field corresponds to Fabry–Perot-like(FP-like) resonance in short wavelengths(600 nm–1200 nm), which predominantly contributes to the temperature localization. These findings provide novel insights into utilizing conical nanostructures for applications such as catalysis.展开更多
Fractional optical vortices in the terahertz(THz)regime are supposed to have unique applications in various areas,i.e.,THz communications,optical manipulations,and THz imaging.However,it is still challenging to genera...Fractional optical vortices in the terahertz(THz)regime are supposed to have unique applications in various areas,i.e.,THz communications,optical manipulations,and THz imaging.However,it is still challenging to generate and manipulate high-power THz vortices.Here,we present a way to generate intense THz vortex beams with a continuously tunable topological charge by injecting a weakly relativistic ultrashort laser pulse into a parabolic plasma channel.By adjusting the injection conditions of the laser pulse,the trajectory of the laser centroid can be twisted into a cylindrical spiral,along which laser wakefields are also excited.Due to the inhomogeneous transverse density profile of the plasma channel and laser wakefield excitation,intense THz radiation carrying orbital angular momentum is produced with field strength reaching sub-GV/m,even though the drive laser energy is at a few tens of mJ.The topological charge of such a radiation is determined by the laser trajectories,which are continuously tunable as demonstrated by theoretical analysis as well as three-dimensional particle-in-cell simulations.Such THz vortices with unique properties may find applications in broad areas.展开更多
MicroMagnetic.jl is an open-source Julia package for micromagnetic and atomistic simulations.Using the features of the Julia programming language,MicroMagnetic.jl supports CPU and various GPU platforms,including NVIDI...MicroMagnetic.jl is an open-source Julia package for micromagnetic and atomistic simulations.Using the features of the Julia programming language,MicroMagnetic.jl supports CPU and various GPU platforms,including NVIDIA,AMD,Intel,and Apple GPUs.Moreover,MicroMagnetic.jl supports Monte Carlo simulations for atomistic models and implements the nudged-elastic-band method for energy barrier computations.With built-in support for double and single precision modes and a design allowing easy extensibility to add new features,MicroMagnetic.jl provides a versatile toolset for researchers in micromagnetics and atomistic simulations.展开更多
The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are a...The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are analyzed.The frequency range of self-excited vibrations is investigated from the energy point of view.The phenomenon of self-excited vibrations is elaborated with the phase trajectory.The corresponding control strategies are briefly analyzed with respect to the vibration mechanism.The results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.展开更多
A novel scheme to suppress both stimulated Brillouin scattering(SBS) and stimulated Raman scattering(SRS) by combining an alternating frequency(AF) laser and a transverse magnetic field is proposed. The AF laser allow...A novel scheme to suppress both stimulated Brillouin scattering(SBS) and stimulated Raman scattering(SRS) by combining an alternating frequency(AF) laser and a transverse magnetic field is proposed. The AF laser allows the laser frequency to change discretely and alternately over time. The suppression of SBS is significant as long as the AF difference is greater than the linear growth rate of SBS or the alternating time of the laser frequency is shorter than the linear growth time of SBS. However, the AF laser proves ineffective in suppressing SRS, which usually has a much higher linear growth rate than SBS. To remedy that, a transverse magnetic field is included to suppress the SRS instability. The electrons trapped in the electron plasma waves(EPWs) of SRS can be accelerated by the surfatron mechanism in a transverse magnetic field and eventually detrapped. While continuously extracting energy from EPWs, the EPWs are dissipated and the kinetic inflation of SRS is suppressed. The one-dimensional particle-in-cell simulation results show that both SBS and SRS can be effectively suppressed by combining the AF laser with a transverse magnetic field with tens of Tesla. The total reflectivity can be dramatically reduced by more than one order of magnitude. These results provide a potential reference for controlling SBS and SRS under the related parameters of inertial confinement fusion.展开更多
基金supported by the National Key R&D Program of China(Grant No.2020YFC2200500)the Key Laboratory of Tian Qin Project(Sun Yat-sen University),Ministry of Education+1 种基金the National Natural Science Foundation of China(Grant Nos.12075325,12005308,and 11605065)the Doctoral Research Foundation Project of Hubei University of Arts and Science(Grant No.kyqdf2059017)。
文摘The effect from the interaction of the alternating current(AC)magnetic field with kilogram-level test mass(TM)limits the detectivity of the TianQin space-based gravitational wave detection.The quantifed effect requires the determination of the AC magnetic susceptibilityχ(f)of the TM.A torque method is proposed to measure theχ(f)of kg-level samples at the mHz band with a precision of 1×10^(-7).Combined with our previous work[Phys.Rev.Appl.18044010(2022)],the general frequency-dependent susceptibility of the alloy cube with side length L and electrical conductivityσis determined asχ(f)=χ0+(0.24±0.01)σμ0L^(2)f from 0.1 mHz to 1 Hz.The determination is helpful for the preliminary estimation of the in-band eddy current efect in the TianQin noise budget.The technique can be adopted to accurately measureχ(f)of the actual TM in other precision experiments,where the magnetic noise is a signifcant detection limit.
基金supported by the National Natural Science Foundation of China(Nos.52025132,U24A20205,52303373,21621091,22021001,and 22121001)the China Postdoctoral Science Foundation(No.2024M763174)+2 种基金the 111 Project(Nos.B17027,B16029)the Natural Science Foundation of Fujian Province of China(No.2022J02059)the New Cornerstone Science Foundation through the Xplorer Prize。
文摘Controllable liquid manipulation is of paramount scientific and technological importance in various fields,such as the chemical industry,biomedicine,and agricultural production.Magnetic actuation,characterized by rapid,contactless,and environmentally benign operation,has emerged as a promising approach for precise liquid control.However,conventional magnetic strategies typically govern droplet movement on open surfaces,facing limitations such as restricted liquid volumes,uncertain flow paths,and inevitable evaporation,thereby constraining their broader practical applications.Recently,a variety of magneticdriven strategies have been developed to dynamically regulate liquids within enclosed spaces,especially through physicochemical mechanisms.These approaches provide efficient control over liquid behavior by leveraging magnetically induced chemical changes,structural deformations,and dragging motions,opening new opportunities for flexible and versatile fluid management.This review explores the design and mechanisms of magneto-responsive confined interfaces for the manipulation of nonmagnetic liquids,highlighting key advancements and potential applications including liquid valves,liquid mixing,liquid flow regulation,and liquid pumping.Finally,the existing challenges and future prospects in this field are presented.
基金Project supported by the Science and Technology Department of Gansu Province, China (Grant No. 24RCKB011)the National Natural Science Foundation of China (Grant No. 12325511)。
文摘The utilization of nanostructures with diverse geometric shapes is essential for manipulating the energy of electromagnetic(EM) fields and achieving various applications in optics, such as nanofocusing. The plasmonic cone structure is highly representative in the field of nanofocusing applications, effectively guiding EM field energy to the tip of the cone and resulting in high local electric field and temperature effects. In certain chemical catalytic applications, an elevated temperature and a larger surface area may be required to enhance catalysis reactions. Here, we propose a hollow gold nanocone structure that can achieve higher temperature both at the tip and within its hollow region under the excitation of an EM field.Through rigorous finite element method(FEM) simulations, we investigated the EM field and temperature distribution of the hollow cone at various cone angles and identified those angles that yield higher local temperatures. Additionally, the analysis of the scattering cross section of hollow cones reveals that the presence of electric dipole component of the EM field corresponds to Fabry–Perot-like(FP-like) resonance in short wavelengths(600 nm–1200 nm), which predominantly contributes to the temperature localization. These findings provide novel insights into utilizing conical nanostructures for applications such as catalysis.
基金upported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant Nos.XDA25050100 and XDA25010100)the National Natural Science Foundation of China(Grant Nos.12474428,12135009,11991073,and 11991074)the Science and Technology Commission of Shanghai Municipality(Grant Nos.22JC1401900 and 24ZR1436900).
文摘Fractional optical vortices in the terahertz(THz)regime are supposed to have unique applications in various areas,i.e.,THz communications,optical manipulations,and THz imaging.However,it is still challenging to generate and manipulate high-power THz vortices.Here,we present a way to generate intense THz vortex beams with a continuously tunable topological charge by injecting a weakly relativistic ultrashort laser pulse into a parabolic plasma channel.By adjusting the injection conditions of the laser pulse,the trajectory of the laser centroid can be twisted into a cylindrical spiral,along which laser wakefields are also excited.Due to the inhomogeneous transverse density profile of the plasma channel and laser wakefield excitation,intense THz radiation carrying orbital angular momentum is produced with field strength reaching sub-GV/m,even though the drive laser energy is at a few tens of mJ.The topological charge of such a radiation is determined by the laser trajectories,which are continuously tunable as demonstrated by theoretical analysis as well as three-dimensional particle-in-cell simulations.Such THz vortices with unique properties may find applications in broad areas.
基金supported by the National Key R&D Program of China(Grant No.2022YFA1403603)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33030100)+2 种基金the National Natural Science Fund for Distinguished Young Scholar(Grant No.52325105)the National Natural Science Foundation of China(Grant Nos.12374098,11974021,and 12241406)the CAS Project for Young Scientists in Basic Research(Grant No.YSBR-084).
文摘MicroMagnetic.jl is an open-source Julia package for micromagnetic and atomistic simulations.Using the features of the Julia programming language,MicroMagnetic.jl supports CPU and various GPU platforms,including NVIDIA,AMD,Intel,and Apple GPUs.Moreover,MicroMagnetic.jl supports Monte Carlo simulations for atomistic models and implements the nudged-elastic-band method for energy barrier computations.With built-in support for double and single precision modes and a design allowing easy extensibility to add new features,MicroMagnetic.jl provides a versatile toolset for researchers in micromagnetics and atomistic simulations.
基金Project supported by the National Natural Science Foundation of China(No.12372005)。
文摘The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are investigated.The effects of the control and interface parameters on the system's stability are analyzed.The frequency range of self-excited vibrations is investigated from the energy point of view.The phenomenon of self-excited vibrations is elaborated with the phase trajectory.The corresponding control strategies are briefly analyzed with respect to the vibration mechanism.The results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.11975059 and 12005021)。
文摘A novel scheme to suppress both stimulated Brillouin scattering(SBS) and stimulated Raman scattering(SRS) by combining an alternating frequency(AF) laser and a transverse magnetic field is proposed. The AF laser allows the laser frequency to change discretely and alternately over time. The suppression of SBS is significant as long as the AF difference is greater than the linear growth rate of SBS or the alternating time of the laser frequency is shorter than the linear growth time of SBS. However, the AF laser proves ineffective in suppressing SRS, which usually has a much higher linear growth rate than SBS. To remedy that, a transverse magnetic field is included to suppress the SRS instability. The electrons trapped in the electron plasma waves(EPWs) of SRS can be accelerated by the surfatron mechanism in a transverse magnetic field and eventually detrapped. While continuously extracting energy from EPWs, the EPWs are dissipated and the kinetic inflation of SRS is suppressed. The one-dimensional particle-in-cell simulation results show that both SBS and SRS can be effectively suppressed by combining the AF laser with a transverse magnetic field with tens of Tesla. The total reflectivity can be dramatically reduced by more than one order of magnitude. These results provide a potential reference for controlling SBS and SRS under the related parameters of inertial confinement fusion.
