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Dual-band left-handed metamaterials fabricated by using tree-shaped fractal 被引量:1
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作者 许河秀 王光明 +1 位作者 王甲富 杨自牧 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第12期220-231,共12页
A method of fabricating dual-band left-handed metematerials (LHMs) is investigated numerically and experimen- tally by single-sided tree-like fractals. The resulting structure features multiband magnetic resonances ... A method of fabricating dual-band left-handed metematerials (LHMs) is investigated numerically and experimen- tally by single-sided tree-like fractals. The resulting structure features multiband magnetic resonances and two electric resonances. By appropriately adjusting the dimensions, two left-handed (LH) bands with simultaneous negative per- mittivity and permeability are engineered and are validated by full-wave eigenmode analysis and measurement as well in the microwave frequency range. To study the multi-resonant mechanism in depth, the LHM is analysed from three different perspectives of field distribution analysis, circuit model analysis, and geometrical parameters evaluation. The derived formulae are consistent with all simulated results and resulting electromagnetic phenomena, indicating the ef- fectiveness of the established theory. The method provides an alternative to the design of multi-band LHM and has the advantage of not requiring two individual resonant particles and electrically continuous wires, which in turn facilitates planar design and considerably simplifies the fabrication. 展开更多
关键词 planar left-handed metamaterial multi-band metamaterial FRACTAL EIGENMODE
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A planar left-handed metamaterial based on electric resonators 被引量:1
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作者 陈春晖 屈绍波 +3 位作者 王甲富 马华 王新华 徐卓 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第3期210-215,共6页
A planar left-handed metamaterial(LHM) composed of electric resonator pairs is presented in this paper. Theoretical analysis, an equivalent circuit model and simulated results of a wedge sample show that this materi... A planar left-handed metamaterial(LHM) composed of electric resonator pairs is presented in this paper. Theoretical analysis, an equivalent circuit model and simulated results of a wedge sample show that this material exhibits a negative refraction pass-band around 9.6GHz under normal-incidence and is insensitive to a change in incidence angle. Furthermore, as the angle between the arm of the electric resonators and the strip connecting the arms increases, the frequency range of the pass-band shifts downwards. Consequently, this LHM guarantees a relatively stable torlerence of errors when it is practically fabricated. Moreover, it is a candidate for designing multi-band LHM through combining the resonator pairs with different angles. 展开更多
关键词 planar left-handed metamaterial electric resonator multi-band metamaterial
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All-dielectric left-handed metamaterial based on dielectric resonator:design,simulation and experiment
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作者 杨一鸣 王甲富 +5 位作者 夏颂 柏鹏 李哲 王军 徐卓 屈绍波 《Chinese Physics B》 SCIE EI CAS CSCD 2011年第1期339-345,共7页
Dipoles with Lorentz-type resonant electromagnetic responses can realise negative effective parameters in their negative resonant region. The electric dipole and magnetic dipole can realise, respectively, negative per... Dipoles with Lorentz-type resonant electromagnetic responses can realise negative effective parameters in their negative resonant region. The electric dipole and magnetic dipole can realise, respectively, negative permittivity and negative permeability, so both the field distribution forms of electric and magnetic dipoles are fundamentals in designing left-handed metamaterial. Based on this principle, this paper studies the field distribution in high-permittivity dielectric materials. The field distributions at different resonant modes are analysed based on the dielectric resonator theory. The origination and influence factors of the electric and magnetic dipoles are confirmed. Numerical simulations indicate that by combining dielectric cubes with different sizes, the electric resonance frequency and magnetic resonance frequency can be superposed. Finally, experiments are carried out to verify the feasibility of all-dielectric left-handed metamaterial composed by this means. 展开更多
关键词 all-dielectric left-handed metamaterial dielectric resonator magnetic dipole electric dipole
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Propagation of Gaussian beams family through a Kerr-type left-handed metamaterial
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作者 A.Keshavarz M.Naseri 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第4期231-236,共6页
In this paper the propagation of elegant Hermite-cosh-Gaussian, elegant Laguerre Gaussian, and Bessel Gaussian beams through a Kerr left-handed metamaterial (LHM) slab have been studied. A split-step Fourier method ... In this paper the propagation of elegant Hermite-cosh-Gaussian, elegant Laguerre Gaussian, and Bessel Gaussian beams through a Kerr left-handed metamaterial (LHM) slab have been studied. A split-step Fourier method is used to investigate the propagation of laser beams through this media. Numerical simulation shows that Gaussian beams have different focusing behaviors in a Kerr LHM slab with positive or negative nonlinearity. Beam focusing happens in slabs with positive nonlinearity and not in slabs with negative nonlinearity; however, negative nonlinearity is required for a Kerr LHM slab to act like a lens. Additionally, the focusing properties of beams can be controlled by controlling the thickness of the slab or the input power of the incident beam. A multilayer structure is also proposed to have beam focusing by thinner slabs and passing longer distances. 展开更多
关键词 Kerr-type left-handed metamaterial Gaussian beams family split-step Fourier method
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From electromagnetic bandgap to left-handed metamaterials:modelling and applications 被引量:1
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作者 郝阳 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第1期34-40,共7页
In this paper, numerical modelling of left-handed materials (LHMs) is presented using in-house and commercial software packages. Approaches used include the finite-difference time-domain (FDTD) method, finite elem... In this paper, numerical modelling of left-handed materials (LHMs) is presented using in-house and commercial software packages. Approaches used include the finite-difference time-domain (FDTD) method, finite element method (FEM) and method of moments (MoMs). Numerical simulation includes verification of negative refraction and "perfect lenses" construction, investigation of evanescent wave behaviour in layered LHMs, reversed Shell's Law in electromagnetic band gap (EBG)-like structures and construction of LHMs using modified split ring resonators (SRRs). Numerical results were verified to be in good agreement with theory, At the end of this paper, potential applications of LHMs in microwave engineering are discussed. 展开更多
关键词 Numerical modelling Electromagnetic crystals Bandgap left-handed materials (LHMs)
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A novel structure for a broadband left-handed metamaterial
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作者 熊汉 洪劲松 +1 位作者 金大琳 章志敏 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第9期234-238,共5页
A low absorptivity broadband negative refractive index metamaterial with a multi-gap split-ring and metallic cross (MSMC) structure is proposed and investigated numerically and experimentally in the microwave freque... A low absorptivity broadband negative refractive index metamaterial with a multi-gap split-ring and metallic cross (MSMC) structure is proposed and investigated numerically and experimentally in the microwave frequency range. The effective media parameters were retrieved from the numerical and experimental results, which clearly show that there exists a very wide frequency band where the permittivity and permeability are negative. The influence of the structure parameters on the magnetic response and the cut-off frequency of the negative permittivity are studied in detail. This metamaterial would have potential application in designing broadband microwave devices. 展开更多
关键词 metamaterial negative refractive index (NRI) BROADBAND
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Double Negative Left-Handed Metamaterials for Miniaturization of Rectangular Microstrip Antenna
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作者 G. Singh 《Journal of Electromagnetic Analysis and Applications》 2010年第6期347-351,共5页
In this paper, I have explored a significant concept for the miniaturization of microstrip patch antenna configuration by using the double negative (DNG) left-handed Metamaterials, which have dielectric permittivity a... In this paper, I have explored a significant concept for the miniaturization of microstrip patch antenna configuration by using the double negative (DNG) left-handed Metamaterials, which have dielectric permittivity and magnetic permeability both negative, simultaneously. It is achieved through the concept of phase-compensation by thin slab consist of the double positive (DPS) material, which have dielectric permittivity and magnetic permeability both positive, simultaneously and DNG metamaterials as a substrate of the microstrip patch antenna. By combining the DNG metamaterial slab with the slab made of DPS materials form a cavity resonator whose dispersion relation is independent of the sum of thickness of the slabs filling this cavity but it depends on the ratio of their thicknesses. This cavity constitutes by DPS and DNG material is used as substrate of the microstrip antennas and the DNG material slab is behave as phase compensator. 展开更多
关键词 MICROSTRIP ANTENNA Phase COMPENSATION metamaterialS Double NEGATIVE metamaterialS
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Properties of single and multiple defect modes in one-dimensional photonic crystals containing left-handed metamaterials 被引量:1
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作者 Munazza Zulfiqar Ali 《Chinese Optics Letters》 SCIE EI CAS CSCD 2012年第7期69-72,共4页
Wave propagation is studied in structures consisting of alternate left- and right-handed layers. Bragg gap and zero-n gap appear in different frequency regions of the structure. The periodicity of the structure is bro... Wave propagation is studied in structures consisting of alternate left- and right-handed layers. Bragg gap and zero-n gap appear in different frequency regions of the structure. The periodicity of the structure is broken by simply reversing the order of the layers in one half of the structure, resulting in defect modes located inside the zero-n gap and Bragg gap. These modes can be made very narrow by adding more layers in the structure. The defect mode located inside the zero-n gap is sensitive to the symmetry of the structure and insensitive to the angle of incidence of the incoming radiation. Multiple modes are also generated inside the gaps by repeating the structural pattern. Thus, a simple structure can be used for single and multiple modes that are imDortant for different applications. 展开更多
关键词 MODE Properties of single and multiple defect modes in one-dimensional photonic crystals containing left-handed metamaterials LEFT
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Inverse design of mechanical metamaterial achieving a prescribedconstitutive curve 被引量:1
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作者 Zongliang Du Tanghuai Bian +4 位作者 Xiaoqiang Ren Yibo Jia Shan Tang Tianchen Cui Xu Guo 《Theoretical & Applied Mechanics Letters》 CAS CSCD 2024年第1期16-22,共7页
Besides exhibiting excellent capabilities such as energy absorption,phase-transforming metamaterials offer a vast design space for achieving nonlinear constitutive relations.This is facilitated by switching between di... Besides exhibiting excellent capabilities such as energy absorption,phase-transforming metamaterials offer a vast design space for achieving nonlinear constitutive relations.This is facilitated by switching between different patterns under deformation.However,the related inverse design problem is quite challenging,due to the lack of appropriate mathematical formulation and the convergence issue in the post-buckling analysis of intermediate designs.In this work,periodic unit cells are explicitly described by the moving morphable voids method and effectively analyzed by eliminating the degrees of freedom in void regions.Furthermore,by exploring the Pareto frontiers between error and cost,an inverse design formulation is proposed for unit cells.This formulation aims to achieve a prescribed constitutive curve and is validated through numerical examples and experimental results.The design approach presented here can be extended to the inverse design of other types of mechanical metamaterials with prescribed nonlinear effective properties. 展开更多
关键词 metamaterial Pattern-transformation Constitutive curve Inverse design
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Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring 被引量:1
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作者 Yuewei Chen Yanyan Zhou +10 位作者 Zihe Hu Weiying Lu Zhuang Li Ning Gao Nian Liu Yuanrong Li Jing He Qing Gao Zhijian Xie Jiachun Li Yong He 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第2期347-364,共18页
Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant chal... Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant challenges for IHB.Gelatin is the most suitable candidate for IHB since it is a collagen hydrolysate and a substantial part of the extracellular matrix found naturally in most tissues.This study used 3D printing ultrafine fiber networks with metamaterial design to embed into ultra-low elastic modulus hydrogel to create a novel gelatin-based conductive film(GCF)with mechanical programmability.The regulation of GCF nearly covers soft tissue mechanics,an elastic modulus from 20 to 420 kPa,and a Poisson’s ratio from-0.25 to 0.52.The negative Poisson’s ratio promotes conformality with soft tissues to improve the efficiency of biological interfaces.The GCF can monitor heartbeat signals and respiratory rate by determining cardiac deformation due to its high conformability.Notably,the gelatin characteristics of the biodegradable GCF enable the sensor to monitor and support tissue restoration.The GCF metamaterial design offers a unique idea for bioelectronics to develop implantable sensors that integrate monitoring and tissue repair and a customized method for endowing implanted sensors to be highly conformal with soft tissues. 展开更多
关键词 Implantable hydrogel-based bioelectronics Conformality 3D printing metamaterial design
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Ultra-wide band gap and wave attenuation mechanism of a novel star-shaped chiral metamaterial 被引量:1
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作者 Shuo WANG Anshuai WANG +7 位作者 Yansen WU Xiaofeng LI Yongtao SUN Zhaozhan ZHANG Qian DING G.D.AYALEW Yunxiang MA Qingyu LIN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第7期1261-1278,共18页
A novel hollow star-shaped chiral metamaterial(SCM)is proposed by incorporating chiral structural properties into the standard hollow star-shaped metamaterial,exhibiting a wide band gap over 1500 Hz.To broaden the ban... A novel hollow star-shaped chiral metamaterial(SCM)is proposed by incorporating chiral structural properties into the standard hollow star-shaped metamaterial,exhibiting a wide band gap over 1500 Hz.To broaden the band gap,solid single-phase and two-phase SCMs are designed and simulated,which produce two ultra-wide band gaps(approximately 5116 Hz and 6027 Hz,respectively).The main reason for the formation of the ultra-wide band gap is that the rotational vibration of the concave star of two novel SCMs drains the energy of an elastic wave.The impacts of the concave angle of a single-phase SCM and the resonator radius of a two-phase SCM on the band gaps are studied.Decreasing the concave angle leads to an increase in the width of the widest band gap,and the width of the widest band gap increases as the resonator radius of the two-phase SCM increases.Additionally,the study on elastic wave propagation characteristics involves analyzing frequency dispersion surfaces,wave propagation directions,group velocities,and phase velocities.Ultimately,the analysis focuses on the transmission properties of finite periodic structures.The solid single-phase SCM achieves a maximum vibration attenuation over 800,while the width of the band gap is smaller than that of the two-phase SCM.Both metamaterials exhibit high vibration attenuation capabilities,which can be used in wideband vibration reduction to satisfy the requirement of ultra-wide frequencies. 展开更多
关键词 metamaterial ultra-wide band gap wave propagation vibration suppression
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Wireless Power Supply Based on MNG-MNZ Metamaterial for Cardiac Pacemakers
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作者 Weihua Chen Jingtao Jia +2 位作者 Xiaoheng Yan Yuhang Song Jiayi Li 《CES Transactions on Electrical Machines and Systems》 EI CSCD 2024年第1期103-112,共10页
To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-ne... To solve the low power transfer efficiency and magnetic field leakage problems of cardiac pacemaker wireless powering, we proposed a wireless power supply system suitable for implanted cardiac pacemaker based on mu-negative(MNG) and mu-nearzero(MNZ) metamaterials. First, a hybrid metamaterial consisted of central MNG unit for magnetic field concentration and surrounding MNZ units for magnetic leakage shielding was established by theoretical calculation. Afterwards, the magnetic field distribution of wireless power supply system with MNG-MNZ metamaterial slab was acquired via finite element simulation and verified to be better than the distribution with conventional MNG slab deployed. Finally, an experimental platform of wireless power supply system was established with which power transfer experiment and system temperature rise experiment were conducted.Simulation and experimental results showed that the power transfer efficiency was improved from 44.44%,19.42%, 8.63% and 6.19% to 55.77%, 62.39%, 20.81%and 14.52% at 9.6 mm, 20 mm, 30 mm and 50 mm,respectively. The maximum SAR acquired by SAR simulation under human body environment was-7.14 dbm and maximum reduction of the magnetic field strength around the receiving coil was 2.82 A/m. The maximum temperature rise during 30min charging test was 3.85℃,and the safety requirements of human bodies were met. 展开更多
关键词 Cardiac pacemaker MNG metamaterial MNZ metamaterial Wireless power supply system
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Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based Techniques
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作者 Sherly Alphonse S.Abinaya Sourabh Paul 《Computers, Materials & Continua》 SCIE EI 2024年第3期3449-3467,共19页
The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial antennas.The radiation cost and quality factor of the antenna are influenced by the size of the antenna.Metamateri... The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial antennas.The radiation cost and quality factor of the antenna are influenced by the size of the antenna.Metamaterial antennas allow for the circumvention of the bandwidth restriction for small antennas.Antenna parameters have recently been predicted using machine learning algorithms in existing literature.Machine learning can take the place of the manual process of experimenting to find the ideal simulated antenna parameters.The accuracy of the prediction will be primarily dependent on the model that is used.In this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard kernel.Along with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this work.The prediction results of the proposed work are better when compared to the existing models in the literature. 展开更多
关键词 ANTENNA pearson optimization BANDWIDTH metamaterial
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Nonreciprocal thermal metamaterials:Methods and applications
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作者 Zhengjiao Xu Chuanbao Liu +2 位作者 Xueqian Wang Yongliang Li Yang Bai 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第7期1678-1693,共16页
Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,... Nonreciprocity of thermal metamaterials has significant application prospects in isolation protection,unidirectional transmission,and energy harvesting.However,due to the inherent isotropic diffusion law of heat flow,it is extremely difficult to achieve nonreciprocity of heat transfer.This review presents the recent developments in thermal nonreciprocity and explores the fundamental theories,which underpin the design of nonreciprocal thermal metamaterials,i.e.,the Onsager reciprocity theorem.Next,three methods for achieving nonreciprocal metamaterials in the thermal field are elucidated,namely,nonlinearity,spatiotemporal modulation,and angular momentum bias,and the applications of nonreciprocal thermal metamaterials are outlined.We also discuss nonreciprocal thermal radiation.Moreover,the potential applications of nonreciprocity to other Laplacian physical fields are discussed.Finally,the prospects for advancing nonreciprocal thermal metamaterials are highlighted,including developments in device design and manufacturing techniques and machine learning-assisted material design. 展开更多
关键词 thermal metamaterials NONRECIPROCITY NONLINEARITY spatiotemporal modulation
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Terahertz toroidal dipole metamaterial sensors for detection of aflatoxin B1
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作者 徐建伟 欧阳收剑 +4 位作者 段守鑫 邹林儿 叶丹妮 杨思嘉 邓晓华 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期672-676,共5页
Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free,real-time and in situ detection.In this paper,a highly sensitive metamaterial sensor... Terahertz metamaterial biosensors have attracted significant attention in the biological field due to their advantages of label-free,real-time and in situ detection.In this paper,a highly sensitive metamaterial sensor with semi-ring mirror symmetry based on toroidal dipole resonance is designed for a new metamaterial biosensor.It is shown that a refractive index sensitivity of 337.5 GHz per refractive index unit can be achieved under an analyte of saturated thickness near a 1.33 THz transmission dip.For biosensor samples where aflatoxin B1 is dropped on the metamaterial surface in our experiment,dip amplitudes of transmission varying from 0.1904 to 0.203 and 0.2093 are observed as aflatoxin B1 concentrations are altered from 0 to 0.001μg·ml-1 and to 0.01μg·ml-1,respectively.Furthermore,when aflatoxin B1 concentrations are 0.1μg·ml-1,1μg·ml-1,10μg·ml-1 and 100μg·ml-1,dip amplitudes of 0.2179,0.226,0.2384 and 0.2527 and dip redshifts of 10.1 GHz,20.1 GHz,27.7 GHz and 37.6 GHz are respectively observed.These results illustrate high-sensitivity,label-free detection of aflatoxin B1,enriching the applications of sensors in the terahertz domain. 展开更多
关键词 TERAHERTZ metamaterial toroidal dipole aflatoxin B1
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Low-frequency bandgap and vibration suppression mechanism of a novel square hierarchical honeycomb metamaterial
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作者 Xingjian DONG Shuo WANG +5 位作者 Anshuai WANG Liang WANG Zhaozhan ZHANG Yuanhao TIE Qingyu LIN Yongtao SUN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第10期1841-1856,共16页
The suppression of low-frequency vibration and noise has always been an important issue in a wide range of engineering applications.To address this concern,a novel square hierarchical honeycomb metamaterial capable of... The suppression of low-frequency vibration and noise has always been an important issue in a wide range of engineering applications.To address this concern,a novel square hierarchical honeycomb metamaterial capable of reducing low-frequency noise has been developed.By combining Bloch’s theorem with the finite element method,the band structure is calculated.Numerical results indicate that this metamaterial can produce multiple low-frequency bandgaps within 500 Hz,with a bandgap ratio exceeding 50%.The first bandgap spans from 169.57 Hz to 216.42 Hz.To reveal the formation mechanism of the bandgap,a vibrational mode analysis is performed.Numerical analysis demonstrates that the bandgap is attributed to the suppression of elastic wave propagation by the vibrations of the structure’s two protruding corners and overall expansion vibrations.Additionally,detailed parametric analyses are conducted to investigate the effect ofθ,i.e.,the angle between the protruding corner of the structure and the horizontal direction,on the band structures and the total effective bandgap width.It is found that reducingθis conducive to obtaining lower frequency bandgaps.The propagation characteristics of elastic waves in the structure are explored by the group velocity,phase velocity,and wave propagation direction.Finally,the transmission characteristics of a finite periodic structure are investigated experimentally.The results indicate significant acceleration amplitude attenuation within the bandgap range,confirming the structure’s excellent low-frequency vibration suppression capability. 展开更多
关键词 wave propagation vibration suppression metamaterial low-frequency bandgap
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General three-dimensional thermal illusion metamaterials
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作者 刘天丰 王兆宸 +1 位作者 朱展 胡润 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期41-47,共7页
Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificia... Thermal illusion aims to create fake thermal signals or hide the thermal target from the background thermal field to mislead infrared observers,and illusion thermotics was proposed to regulate heat flux with artificially structured metamaterials for thermal illusion.Most theoretical and experimental works on illusion thermotics focus on two-dimensional materials,while heat transfer in real three-dimensional(3D)objects remains elusive,so the general 3D illusion thermotics is urgently demanded.In this study,we propose a general method to design 3D thermal illusion metamaterials with varying illusions at different sizes and positions.To validate the generality of the 3D method for thermal illusion metamaterials,we realize thermal functionalities of thermal shifting,splitting,trapping,amplifying and compressing.In addition,we propose a special way to simplify the design method under the condition that the size of illusion target is equal to the size of original heat source.The 3D thermal illusion metamaterial paves a general way for illusion thermotics and triggers the exploration of illusion metamaterials for more functionalities and applications. 展开更多
关键词 thermal illusion thermal metamaterials transformation thermotics
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A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting
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作者 Long ZHAO Zeqi LU +1 位作者 Hu DING Liqun CHEN 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第7期1243-1260,共18页
Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant cells.It has been demonstrated by several researchers that the dissipatioin of... Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant cells.It has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic materials.This paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration isolation.The viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy harvesters.The nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction coil.The dynamic equations of viscoelastic metamaterials under transverse excitation are established,and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are analyzed.The results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band gap.At the same time,the elastic waves are limited in the nonlinear resonator with an energy harvesting function,which improves the energy output.Finally,an experimental platform of viscoelastic metamaterial vibration is established for validation purposes. 展开更多
关键词 viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting
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Bandgap adjustment of a sandwich-like acoustic metamaterial plate with a frequency-displacement feedback control method
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作者 Jianing LIU Jinqiang LI Ying WU 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第10期1807-1820,共14页
Several types of acoustic metamaterials composed of resonant units have been developed to achieve low-frequency bandgaps.In most of these structures,bandgaps are determined by their geometric configurations and materi... Several types of acoustic metamaterials composed of resonant units have been developed to achieve low-frequency bandgaps.In most of these structures,bandgaps are determined by their geometric configurations and material properties.This paper presents a frequency-displacement feedback control method for vibration suppression in a sandwich-like acoustic metamaterial plate.The band structure is theoretically derived using the Hamilton principle and validated by comparing the theoretical calculation results with the finite element simulation results.In this method,the feedback voltage is related to the displacement of a resonator and the excitation frequency.By applying a feedback voltage on the piezoelectric fiber-reinforced composite(PFRC)layers attached to a cantilever-mass resonator,the natural frequency of the resonator can be adjusted.It ensures that the bandgap moves in a frequency-dependent manner to keep the excitation frequency within the bandgap.Based on this frequency-displacement feedback control strategy,the bandgap of the metamaterial plate can be effectively adjusted,and the vibration of the metamaterial plate can be significantly suppressed. 展开更多
关键词 acoustic metamaterial Hamilton principle electromechanical coupling vibration control local resonance
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Suppression of low-frequency ultrasound broadband vibration using star-shaped single-phase metamaterials
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作者 Rui Zhao Jian Zheng +4 位作者 Jin Guo Yunbo Shi Hengzhen Feng Jun Tang Jun Liu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期217-224,共8页
In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation pr... In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped lattices.The effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and analyzed.The target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent lattices.The proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k Hz.After the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target frequency.These results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment. 展开更多
关键词 Star-shaped metamaterials BROADBAND Vibration attenuation Low-frequency ultrasound vibration Transmission loss
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