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Optimal design of sub-wavelength metal rectangular gratings for polarizing beam splitter based on effective medium theory 认领 引用 被引量：8
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作者 赵华君 彭拥军 +3 位作者 谭菊 廖长荣 李鹏 任晓霞 《Chinese Physics B》 SCIE EI CAS 2009年第12期5326-5330,共5页
A novel optimal design of sub-wavelength metal rectangular gratings for the polarizing beam splitter （PBS） is proposed. The method is based on effective medium theory and the method of designing single layer antiref... A novel optimal design of sub-wavelength metal rectangular gratings for the polarizing beam splitter （PBS） is proposed. The method is based on effective medium theory and the method of designing single layer antireflection coating. The polarization performance of PBS is discussed by rigorous couple-wave analysis （RCWA） method at a wavelength of 1550 nm. The result shows that sub-wavelength metal rectangular grating is characterized by a high reflectivity, like metal films for TE polarization, and high transmissivity, like dielectric films for TM polarization. The optimal design accords well with the results simulated by RCWA method. 展开更多
关键词 polarizing beam splitter sub-wavelength metal rectangular gratings effective medium theory antireflection
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Linear theory of a dielectric-loaded rectangular Cerenkov maser with a sheet electron beam 认领 引用 被引量：2
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作者 陈晔 赵鼎 +2 位作者 刘文鑫 王勇 万晓声 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期245-250,共6页
A three-dimensional model of a dielectric-loaded rectangular Cerenkov maser with a sheet electron beam for the beam-wave interaction is proposed.Based on this model,the hybrid-mode dispersion equation is derived with ... A three-dimensional model of a dielectric-loaded rectangular Cerenkov maser with a sheet electron beam for the beam-wave interaction is proposed.Based on this model,the hybrid-mode dispersion equation is derived with the Borgnis potential function by using the field-matching method.Its approximate solution is obtained under the assumption of a dilute electron beam.By using the Ansoft high frequency structural simulator（HFSS） code,the electromagnetic field distribution in the interaction structure is given.Through numerical calculations,the effects of beam thickness,beam and dielectric-layer gap distance,beam voltage,and current density on the resonant growth rate are analysed in detail. 展开更多
关键词 rectangular Cerenkov maser beam-wave interaction hybrid-mode dispersion equation Borgnis potential function
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Symmetric Equations for Evaluating Maximum Torsion Stress of Rectangular Beams in Compliant Mechanisms 认领 引用 被引量：3
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作者 Gui-Min Chen Larry L.Howell 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2018年第1期34-40,共7页
There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions... There are several design equations available for calculating the torsional compliance and the maximum torsion stress of a rectangular cross-section beam, but most depend on the relative magnitude of the two dimensions of the crosssection(i.e., the thickness and the width). After reviewing the available equations, two thickness-to-width ratio Independent equations that are symmetric with respect to the two dimensions are obtained for evaluating the maximum torsion stress of rectangular cross-section beams. Based on the resulting equations, outside lamina emergent torsional joints are analyzed and some useful design Insights are obtained. These equations, together with the previous work on symmetric equations for calculating torsional compliance, provide a convenient and effective way for designing and optimizing torsional beams in compliant mechanisms. 展开更多
关键词 Compliant mechanism Maximum torsion stress Rectangular beam Lamina emergent joint
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EXACT ANALYSIS OF WAVE PROPAGATION IN AN INFINITE RECTANGULAR BEAM 认领 引用 被引量：2
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作者 孙卫明 杨光松 李东旭 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第7期768-778,共11页
The Fourier series method was extended for the exact analysis of wave propagation in an infinite rectangular beam.Initially,by solving the three-dimensional elastodynamic equations a general analytic solution was deri... The Fourier series method was extended for the exact analysis of wave propagation in an infinite rectangular beam.Initially,by solving the three-dimensional elastodynamic equations a general analytic solution was derived for wave motion within the beam.And then for the beam with stress-free boundaries,the propagation characteristics of elastic waves were presented.This accurate wave propagation model lays a solid foundation of simultaneous control of coupled waves in the beam. 展开更多
关键词 infinite rectangular beam wave propagation exact analysis Fourier series traveling wave active control
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Bending waves of a rectangular piezoelectric laminated beam 认领 引用 被引量：6
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作者 C.P.Wei C.X.Xue 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2020年第5期1099-1108,I0003,共10页
A simple nonlinear model is proposed in this paper to study the bending wave in a rectangular piezoelectric laminated beam of infinite length.Based on the constitutive relations for transversely isotropic piezoelectri... A simple nonlinear model is proposed in this paper to study the bending wave in a rectangular piezoelectric laminated beam of infinite length.Based on the constitutive relations for transversely isotropic piezoelectric materials and isotropic elastic materials,combined with some electric conditions,we derive the bending wave equation in a long rectangular piezoelectric laminated beam by using energy method.The nonlinearity considered is geometrically associated with the nonlinear normal strain in the longitudinal beam direction.The shock-wave solution,solitary-wave solution and other exact solutions of the bending wave equation are obtained by the extended F-expansion method.And by using the reductive perturbation method we derive the nonlinear Schrodinger(NLS)equation,further more,the bright and dark solitons are obtained.For those soliton solutions,and some parameters derived by the process of solving soliton solutions,some conclusions are drawn by numerical analysis with some fixed conditions. 展开更多
关键词 Bending wave Rectangular piezoelectric laminated beam Extended F-expansion method Nonlinear Schrodingereruation
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Novel Even Beam Splitters Based on Subwavelength Binary Simple Periodic Rectangular Structure 认领 引用 被引量：11
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作者 Haixuan Huang Shuangchen Ruan +1 位作者 Tuo Yang Ping Xu 《Nano-Micro Letters》 SCIE EI CAS 2015年第2期177-182,共6页
In this paper, a novel method of a subwavelength binary simple periodic rectangular structure is presented to realize even beam splitting by combining the rigorous couple-wave analysis with the genetic algorithm. Seve... In this paper, a novel method of a subwavelength binary simple periodic rectangular structure is presented to realize even beam splitting by combining the rigorous couple-wave analysis with the genetic algorithm. Several even splitters in the terahertz region were designed and one of the silicon-based beam splitters designed to separate one incident beam into four emergent beams has total efficiency up to 92.23 %. Zero-order diffraction efficiency was reduced to less than 0.192 % and the error of uniformity decreased to 6.51 9 10-6. These results break the limitation of even beam splitting based on the traditional scalar theory. In addition, the effects of the incident angle, wavelength, as well as the polarizing angle on the diffraction efficiency and uniformity were also investigated. 展开更多
关键词 Beam splitters Binary optics Diffraction gratings Diffraction theory Subwavelength structures
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Statics of FGM circular plate with magneto-electro-elastic coupling:axisymmetric solutions and their relations with those for corresponding rectangular beam 认领 引用 被引量：2
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作者 Yanzheng WANG Weiqiu CHEN Xiangyu LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2015年第5期581-598,共18页
This paper investigates the static behavior of a functionally graded circular plate made of magneto-electro-elastic（MEE） materials under tension and bending.The analysis is directly based on the three-dimensional go... This paper investigates the static behavior of a functionally graded circular plate made of magneto-electro-elastic（MEE） materials under tension and bending.The analysis is directly based on the three-dimensional governing equations for magnetoelectro-elasticity, with the boundary conditions on the upper and lower surfaces satisfied exactly and those on the cylindrical surface satisfied approximately（in the Saint Venant sense）. The analytical solutions, derived with a direct displacement method, are valid for any functionally graded material（FGM） with its properties varying independently in a continuous manner along the thickness direction. For homogeneous materials, these solutions are degenerated to the ones available in the literature. Interesting relations are also found between the solutions for a functionally graded magneto-electro-elastic（FGMEE） circular plate and those for an FGMEE rectangular beam, and even those for a functionally graded elastic beam when only the elastic displacements are considered. The beam solutions are also derived using a direct displacement method. Numerical examples are presented to verify the present analytical solutions, show the effects of material heterogeneity and multi-field coupling, and indicate the correspondence between the plate solutions and beam solutions. 展开更多
关键词 functionally graded circular rectangular magneto correspondence elasticity heterogeneity exactly piezoelectric
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EXPERIMENTAL RESEARCH AND NONLINEAR FINITE ELEMENT ANALYSIS ON NEW TYPE JOINT BETWEEN COLUMN AND STEEL BEAM OF CONCRETE-FILLED RECTANGULAR STEEL TUBULAR 认领 引用 被引量：4
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作者 于旭 宰金珉 刘伟庆 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2009年第1期75-82,共8页
Experimental results of new type joints between the column and the. steel beam of concrete-filled rectangular steel tubular （CFRT） under reversed cyclic loads are presented. The earthquake resistant capacity of the ... Experimental results of new type joints between the column and the. steel beam of concrete-filled rectangular steel tubular （CFRT） under reversed cyclic loads are presented. The earthquake resistant capacity of the joint is influenced by infilled concrete, stiffener length and relative dimensions of column and beam. It is found that the hysteresis curves obtained in the experiment are full and the joints have a good energy dissipation capacity. The nonlinear finite element models are also used to analyze the hysteresis behavior of the joints under reversed cyclic loads using ANSYS 8.0. The influences of the stiffener length and the infilled concrete are analyzed. Analytical results show that the stiffener length and the infilled concrete are critical for the joints. Furthermore, the skeleton curves of the finite element models are in good agreement with those of experiments. 展开更多
关键词 joints cyclic loads finite element method concrete-filled rectangular steel tubular （CFRT）
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Influences of Installment Tensioning Technology on Bearing Capacity of Rectangular Prestressed Concrete Beam 认领 引用 被引量：1
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作者 Hongyan Ding Peng Liu +2 位作者 Puyang Zhang Yan Zhu Yaohua Guo 《Transactions of Tianjin University》 EI CAS 2017年第2期122-129,共8页
To obtain the relationship between use of installment tensioning technology and the bearing capacity of prestressed concrete beams, tensile and cyclic loading tests are conducted on five rectangular prestressed concre... To obtain the relationship between use of installment tensioning technology and the bearing capacity of prestressed concrete beams, tensile and cyclic loading tests are conducted on five rectangular prestressed concreted specimens. Two types of prestressed tensioning methods are adopted in the tests, one uses installment tensioning technology to tension beams on days 4, 12, and 8, 12, respectively, and the other adopts the conventional method to tension the beam on day 28 only. The age of concrete, number of times tensioned, and the prestress value of early tensioning are considered in tests. Results show that use of installment tensioning technology has no effect on the bending failure pattern of prestressed concrete beams, but it reduces prestress loss and increases crack and yield loads. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg. 展开更多
关键词 Bearing capacity Concretes Cyclic loads Prestressed beams and girders Prestressed concrete
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ELECTRON OPTICS OF VARIABLE RECTANGULAR SHAPED BEAM LITHOGRAPHY SYSTEM D J-2 认领 引用
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作者 康念坎 《Journal of Electronics(China)》 1993年第2期170-180,共11页
The electron optical column for the variable rectangular-shaped beam lithographysystem DJ-2 is described,with emphasis on the analysis of the optical configuration and theshaping deflection compensation.In this column... The electron optical column for the variable rectangular-shaped beam lithographysystem DJ-2 is described,with emphasis on the analysis of the optical configuration and theshaping deflection compensation.In this column the variable spot shaping is performed with aminimum number of lenses by a more reasonable optical scheme.A high-sensitivity electrostaticshaping deflector with sequential parallel-plates is implemented for high-speed spot shaping.With a precise linear and rotational approach,the spot current density,the edge resolution aswell as the position of spot origin remain unchanged when the spot size varies.Experiments showthat the spot current density of over 0.4 A/cm^2 is obtained with a tungsten hairpin cathode,andthe edge resolution is better than 0.2μm within a 2×2 mm^2 field size. 展开更多
关键词 Electron optics Electron beam lithography Variable rectangular-shaped beam
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Relative-Intensity Squeezing of High-Order Harmonic Twin Beams 认领 引用
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作者 Shicheng Jiang Konstantin Dorfman 《Chinese Physics Letters》 SCIE EI CAS CSCD 2026年第5期61-77,共17页
Relative intensity squeezing(RIS)is emerging as a promising technique for performing high-precision measurements beyond the shot-noise limit.A commonly used way to produce RIS in the visible/infrared range is generati... Relative intensity squeezing(RIS)is emerging as a promising technique for performing high-precision measurements beyond the shot-noise limit.A commonly used way to produce RIS in the visible/infrared range is generating correlated“twin beams”through four-wave mixing by driving atomic resonances with weak laser beams.Here,we propose an all-optical strong-field scheme to produce a series of relative-intensity-squeezed high-order harmonic“twin beams”.Due to the nature of high-harmonic generation,the frequencies of the“twin beams”can cover a broad range of photon energy.Our proposal paves the way for the development of non-classical XUV sources and high precision spectroscopy tools in the strong-field regime. 展开更多
关键词 relative intensity squeezing ris high order harmonic generating correlated twin beams relative intensity squeezing driving atomic resonances weak laser beamsherewe twin beams all optical strong field scheme non classical xuv sources
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Rectangular Microstrip Antenna for Symmetrical 3-D Beam Widths for an Efficient Feed of Reflector Antenna and its Quantitative Analysis 认领 引用
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作者 Jitendra Kr. Sah Sun Chatterjee +3 位作者 Pragya Bharati Dia Ghosh Aditi Anand Sudipta Chattopadhyay 《Journal of Electromagnetic Analysis and Applications》 2012年第6期230-234,共5页
A simple rectangular microstrip antenna on low dielectric constant substrate such as air for improved radiation beam performance is theoretically investigated. The conventional patch antenna fabricated on common subst... A simple rectangular microstrip antenna on low dielectric constant substrate such as air for improved radiation beam performance is theoretically investigated. The conventional patch antenna fabricated on common substrates always produces quite broader E plane pattern compared to its H plane. In the present investigation, the same microstrip antenna is designed on air substrate with a view to develop an efficient feed for parabolic reflector antenna, which shows an excellent radiation pattern with symmetrical 3 dB beam widths at its both E and H plane. The present antenna compared to conventional structure to show its excellence in the beam performance is presented. The complete quantitative analysis to explore such radiation beam characteristics for both the structures (conventional and the present one) is also presented in this paper. An easy and handful relationship between the length of patch antenna and its fringing length for different types of substrate is established in the background of 3 dB beam widths. The proposed idea has been verified through a commercial software package for a patch operating in X band and a concrete physical insight into the phenomenon is developed. 展开更多
关键词 Air Substrate Rectangular Microstrip Antenna Symmetrical Beam widths.
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One-dimensional dynamic equations of a piezoelectric semiconductor beam with a rectangular cross section and their application in static and dynamic characteristic analysis 认领 引用 被引量：7
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作者 Peng LI Feng JIN Jianxun MA 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2018年第5期685-702,共18页
Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. The... Within the framework of continuum mechanics, the double power series ex- pansion technique is proposed, and a series of reduced one-dimensional （1D） equations for a piezoelectric semiconductor beam are obtained. These derived equations are universal, in which extension, flexure, and shear deformations are all included, and can be degen- erated to a number of special cases, e.g., extensional motion, coupled extensional and flexural motion with shear deformations, and elementary flexural motion without shear deformations. As a typical application, the extensional motion of a ZnO beam is analyzed sequentially. It is revealed that semi-conduction has a great effect on the performance of the piezoelectric semiconductor beam, including static deformations and dynamic be- haviors. A larger initial carrier density will evidently lead to a lower resonant frequency and a smaller displacement response, which is a little similar to the dissipative effect. Both the derived approximate equations and the corresponding qualitative analysis are general and widely applicable, which can clearly interpret the inner physical mechanism of the semiconductor in the piezoelectrics and provide theoretical guidance for further experimental design. 展开更多
关键词 piezoelectric semiconductor beam reduced one-dimensional （1D） equation,double power series expansion technique stress relaxation initial carrier density
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Narrow beam and low-sidelobe electro-optic beam steering on thinfilm lithium niobate optical phased array 认领 引用 被引量：1
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作者 Yang Li Shiyao Deng +9 位作者 Xiao Ma Ziliang Fang Shufeng Li Weikang Xu Fangheng Fu Xu Ouyang Yuming Wei Tiefeng Yang Heyuan Guan Huihui Lu 《Opto-Electronic Science》 CAS 2026年第2期2-12,共11页
Optical beam steering has become indispensable in free-space optical communications,light detection and ranging(LiDAR),mapping,and projection.Optical phased array(OPA)leads this field as versatile and miniaturized pla... Optical beam steering has become indispensable in free-space optical communications,light detection and ranging(LiDAR),mapping,and projection.Optical phased array(OPA)leads this field as versatile and miniaturized platform to this end,yet conventional versions still suffer from a narrow steering field of view,insufficient sidelobe suppression,and limited angular resolution in electro-optic(EO)beam steering.Thin-film lithium niobate(LN),with its strong EO effect,offers a powerful integrated-photonics platform to overcome these limitations.Here we present a two-dimensional(2D)EO-steered OPA based on a non-uniformly spaced X-cut thin-film LN ridge-waveguide array.A superlattice ridge design suppresses optical crosstalk to−20 dB,enabling low-sidelobe far-field radiation.Using particle swarm optimization method,we transform a uniformly spaced waveguide array into an optimized nonuniform design,largely improving angular resolution while maintaining sidelobe suppression.When combined with a single-radiating trapezoidal end-fire emitter incorporating an etched grating,the device produces a main-lobe beam with fine width of 0.99°×0.63°from an aperture of only 140μm×250μm,achieving a wide 2D steering range of 47°×9.36°with a 20 dB sidelobe-suppression ratio.These results highlight thin-film LN OPA as a compelling route toward ultra-compact,high-performance high-speed EO beam-steering modules and optical free-space modulators. 展开更多
关键词 non-uniform lithium niobate waveguide arrays superlattice waveguide optical beam steering narrow beam low sidelobe
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Polarization-and mode-multiplexed programmable liquid crystal metasurface for terahertz tri-band beam scanning 认领 引用
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作者 FAN LI JIERONG CHENG +7 位作者 CHENGLONG LIU JIEYANG TANG SHENGNAN GUAN HAIFENG XU FEI FAN SHIYING HAN SAI CHEN SHENGJIANG CHANG 《Photonics Research》 SCIE EI CAS CSCD 2026年第7期3029-3036,共8页
Liquid crystal(LC)metasurfaces offer a promising platform for programmable terahertz beam scanning,benefiting from low-power electrical driving and mature large-area fabrication.However,conventional resonant meta-atom... Liquid crystal(LC)metasurfaces offer a promising platform for programmable terahertz beam scanning,benefiting from low-power electrical driving and mature large-area fabrication.However,conventional resonant meta-atoms typically limit the modulation bandwidth to below 20 GHz,and the incident polarization must align with the LC pre-orientation to ensure high modulation depth.Here,we propose an LC metasurface that simultaneously enables polarization-multiplexing and mode-multiplexing to overcome the narrow-band and strict polarization constraints.By synergistically designing the metasurface to satisfy both electrical feeding and resonant requirements,we realize efficient excitation and pixel-wise independent control of the x-polarized magnetic dipole,y-polarized magnetic dipole,and toroidal dipole modes.Consequently,the device supports tri-band beam steering with±45°scanning angles around 0.27 THz and 0.37 THz,and ±13° around 0.81 THz,covering an overall bandwidth of 188 GHz.Our experiments verify that the incident polarization can be decoupled from the LC pre-alignment requirement,while higher-order resonant modes serve as an effective strategy to broaden the operating bandwidth without compromising spatial resolution and array size.By integrating polarization and frequency multiplexing in a programmable 48×48 active array,this work opens,to our knowledge,new avenues toward high-capacity,dynamically programmable terahertz beam manipulation. 展开更多
关键词 high capacity beam manipulation polarization multiplexing programmable array lc metasurface liquid crystal metasurface terahertz beam scanning mode multiplexing programmable terahertz beam scanningbenefiting
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Machine learning for beam correction study of the injection beamline at Wuhan Advanced Light Source 认领 引用
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作者 Hui Wang Hao‑Hu Li +4 位作者 Jia‑Bao Guan Yuan Chen Ji‑Ke Wang Yuan‑Cun Nie Jian‑Hua He 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2026年第8期1-15,共15页
Wuhan Advanced Light Source(WALS),a fourth-generation synchrotron radiation light source operating at 1.5 GeV,is currently under design and will use a full-energy linear accelerator(LINAC)as the electron beam injector... Wuhan Advanced Light Source(WALS),a fourth-generation synchrotron radiation light source operating at 1.5 GeV,is currently under design and will use a full-energy linear accelerator(LINAC)as the electron beam injector.The injection beamline adopts a three-stage scheme:First,the beam from the LINAC,which is 6 m below the storage ring,is horizontally deflected below the storage ring;second,it gradually climbs from underground to the same altitude as the storage ring;and third,the beam is delivered horizontally into the injection straight section inside the storage ring.Twiss parameter matching between the LINAC and storage ring was also completed.During the construction of the beamline,magnet manufacturing errors,installation errors,and beam injection errors from the LINAC will cause beam deviations from the predetermined ideal orbits and even particle losses.Therefore,electron beam correction is required during beam commissioning.In contrast with the single-plane beam correction used in general transfer lines,the horizontal and vertical directions of the beam are coupled in the WALS injection transfer line,which greatly increases the complexity and difficulty of beam correction.Machine learning technology has been extensively developed in recent years,and the powerful invertible neural network algorithm is expected to solve the beam commissioning challenge of the beam injection transfer line at the WALS.Therefore,an invertible neural network(INN)model has been designed and trained to simulate the beam transport and beam correction of the WALS injection beamline.By optimizing the number and positions of beam profile monitors,the accuracy of both bidirectional prediction and beam correction can be greatly improved.This method has important practical significance for the commissioning and operation of similar complex beam transport systems. 展开更多
关键词 Beam correction Injection transfer beamline Machine learning Beam dynamics Invertible neural network
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Generation of high-yield,azimuthally spin-polarized positron beams from relativistic electrons in cone-channel targets 认领 引用
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作者 Yue Cao Si-Man Liu +6 位作者 Kun Xue Li-Xiang Hu Jing-Yi Wang Qian-Ni Li Xin-Yu Liu Jian-Xing Li Tong-Pu Yu 《Matter and Radiation at Extremes》 SCIE EI CAS CSCD 2026年第4期51-58,共8页
High-energy,high-yield structured spin-polarized positron beams have important applications in nuclear physics,high-energy physics,and information storage.However,their generation remains a significant challenge.Here,... High-energy,high-yield structured spin-polarized positron beams have important applications in nuclear physics,high-energy physics,and information storage.However,their generation remains a significant challenge.Here,we put forward a scheme to generate these beams using a dense relativistic electron beam interacting with a gas-filled cone-channel target.The interaction induces composite focusing fields comprising the electric field from a plasma bubble and skin-layer magnetic fields from the electron beam and displacement currents.These fields compress the seed beam to ultrahigh density,thereby inducing extreme fields that enable efficient γ-photon emission and subsequent pair production,leading to a high positron yield.Furthermore,the azimuthal topology of these fields is imprinted onto the generated positrons,creating unique azimuthal polarization.Our simulations demonstrate the generation of an azimuthally polarized positron beam with a charge of 0.63 nC,a polarization approaching 60%,and an energy conversion efficiency exceeding 3%.Our method provides a highly efficient pathway for generating azimuthally polarized positrons,paving the way for their potential applications. 展开更多
关键词 cone channel targets azimuthally spin polarized positron beams relativistic electrons electric field plasma bubble electron beam dense relativistic electron beam composite focusing fields
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A Novel Raman Spectrometer using Bessel-like Laser Beam for Homogeneous Phases and Interface Detections 认领 引用
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作者 Ning Chen Yuhui Li +3 位作者 Tianle Zhang Jin Yang Xiaoguo Zhou Shilin Liu 《Chinese Journal of Chemical Physics》 SCIE EI CAS CSCD 2026年第3期318-327,I0004-I0006,共10页
Bessel beams,often referred to as“nondiffractive”light,have been successfully applied in numerous fields.In this study,we integrated a Bessel beam as the illumination source into a Raman spectrometer to enhance the ... Bessel beams,often referred to as“nondiffractive”light,have been successfully applied in numerous fields.In this study,we integrated a Bessel beam as the illumination source into a Raman spectrometer to enhance the detection of homogeneous phases and interfaces.By simulating optical path systems,we optimized the setup to fully utilize the multi-pixel array and maximize detection sensitivity.Compared to a conventional Gaussian-beam Raman spectrometer in the 90°-scattered configuration,the upgraded Raman spectrometer employing a Bessel-like beam demonstrated a nearly 6-fold improvement in sensitivity.Additionally,it significantly suppressed background scattering interferences in the low-frequency range,thus enhancing the clarity and accuracy of spectral data.Furthermore,the capability of this spectrometer for real-space Raman imaging of heterogeneous phase interfaces was verified.This advancement not only improves the sensitivity and precision of Raman measurements but also expands the potential applications of Raman spectroscopy in studying complex systems,such as interfaces and phase boundaries,with high spatial and spectral resolution. 展开更多
关键词 Raman spectroscopy Raman imaging Interface Bessel beam Gaussian beam
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Online beam phase calibration with detuning compensation for normal-conducting cavities under closed-loop operation 认领 引用
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作者 Feng Qiu Cheng-Ye Xu +10 位作者 Ri-Hua Zeng Yuan He Shi-Hui Wei Jia-Yi Peng Li-Juan Yang Zi-Qin Yang Zhou-Li Zhang Zhi-Jun Wang Mu-Yuan Wang Cecilia Maiano Paolo Pierini 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2026年第6期15-30,共16页
Accurate calibration of the beam phase(i.e.,the phase of the beam arrival relative to the cavity accelerating field)is essential for maintaining the stability and efficiency of linear accelerators.Conventional offline... Accurate calibration of the beam phase(i.e.,the phase of the beam arrival relative to the cavity accelerating field)is essential for maintaining the stability and efficiency of linear accelerators.Conventional offline phase-scan methods,such as theΔT phase scan and phase-scan signature matching,are typically performed during commissioning or maintenance,requiring the accelerator to be taken out of normal operation.Moreover,these methods cannot effectively track the gradual drifts caused by ambient conditions.An online beam phase calibration technique using beam-induced radio-frequency(RF)transients was initially developed at DESY for superconducting cavities operating under open-loop conditions.Extending the DESY method to normal-conducting cavities at the European Spallation Source(ESS)introduces challenges.When the beam pulse length approaches the cavity time constantτ=1∕ω0.5,whereω0.5is the cavity half bandwidth,the detuning effects distort the trajectory of the beam-induced RF transient and degrade the beam phase measurement accuracy.Furthermore,open-loop operation is generally not advisable for high-current proton linacs because of stability and safety concerns associated with the operation.To address these issues,we revisited the cavity differential equations and proposed a detuning compensation method that corrects the distorted trajectory in the in-phase/quadrature plane of the laser beam.In addition,by analyzing the initial 1.4μs transient response before low-level RF(LLRF)feedback becomes active,beam phase calibration can be achieved under closed-loop operation.The experimental results indicate that the proposed method agrees well with beam position monitor(BPM)-based measurements.This approach enables real-time beam phase monitoring without interrupting the closed-loop operation and can be adapted to similar accelerator systems. 展开更多
关键词 Beam phase calibration Transient beam loading Detuning effect Closed-loop operation Low-level RF systems Normal-conducting cavity Particle accelerator
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Dynamical analysis and nonlinear vibration control of integrated composite beam structure in thermal environment 认领 引用
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作者 Donghui LI Faming ZHANG +4 位作者 Qunfang LI Shang GAO Jian ZANG Yewei ZHANG Fengtian YANG 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2026年第1期278-300,共23页
Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery supp... Traditional dynamic analysis of mechanical structures,often limited to individual beams or plates,fails to fully capture their dynamic behaviors.In systems where space and mass are constrained,such as the battery support structures in electric aircraft,conventional absorbers and isolators are insufficient for effective vibration control.This study simplifies the battery support structure of electric aircraft as an integrated composite beam consisting of three interconnected beams,and investigated its structural dynamics properties and nonlinear vibration control under thermal conditions caused by battery heat.The nonlinear vibration control is performed using the Nitinol steel wire ropes(Ni Ti-ST),with nonlinear damping properties.The natural frequencies of system are determined using the Rayleigh-Ritz technique.Theoretical results are validated through both Finite Element Method(FEM)and hammer tests.Moreover,the dynamic equations are derived using the Lagrange method and discretized via the Galerkin Truncation Method(GTM).The Harmonic Balance Method(HBM)is used to evaluate the vibration responses of the integrated model,with further verification through the Runge-Kutta Method(RKM).The experiments are conducted to corroborate the theoretical analysis.The results show that the system frequency changes in stages with the increase of the stiffness of the integrated composite beam connection.Especially in the case of varying environments,as the temperature increases,the frequency of system will first increase to a certain maximum value and then gradually decrease.Furthermore,the NiTi-ST effectively reduces vibration in the integrated composite beam,particularly under varying temperatures and external excitations. 展开更多
关键词 Composite laminated beam Dynamics characteristic Integrated composite beam Modal experiment NiTiNOL steel wire rope Nonlinear vibration control
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