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Finite-Element Analysis of Three-Dimensional Axisymmetrical Invisibility Cloaks and Other Metamaterial Devices

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Communications in Computational Physics 2010年第9期8卷 823-834页

作者： Yong Bo Zhai Xue wei Ping wei xiang jiang Tie Jun Cui State Key Laboratory of Millimeter Waves and the Institute of Target Characteristics and Identification Department of Radio EngineeringSoutheast UniversityNanjing 210096China

Accurate simulations of metamaterial devices are very important in the analysis of their electromagnetic ***,it is very difficult to make full-wave simulations of three-dimensional(3D)metamaterial devices due to the huge memory requirements and long computing *** this paper,we present an efficient finiteelement method(FEM)to analyze 3D axisymmetric electromagnetic devices designed by the transformation-optics approach,such as invisibility cloaks and *** the proposed method,we use the edge-based vector basis functions to expand the transverse field components,and the node-based scalar basis functions to expand the angular *** FEM mesh is truncated with a cylindrical perfectly matched *** have applied the method to investigate the scattering from spherical and ellipsoidal invisibility cloaks and circularly cylindrical concentrators,in which the permittivity and permeability are both inhomogeneous and *** results are presented to show the validity and efficiency of the method.

关键词： Finite-element method axisymmetrical scatterer metamaterial devices

A metasurface-based light-to-microwave transmitter for hybrid wireless communications

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Light(Science & Applications) 2022年第6期11卷 1139-1148页

作者： Xin Ge Zhang Ya Lun Sun Bingcheng Zhu wei xiang jiang Qian Yu Han wei Tian Cheng-wei Qiu Zaichen Zhang Tie Jun Cui State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast University210096 NanjingChina National Mobile Communications Research Laboratory School of Information Science and EngineeringSoutheast University210096 NanjingChina Frontiers Science Center for Mobile Information Communication and Security Southeast University210096 NanjingChina Purple Mountain Laboratories 211111 NanjingChina Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore

Signal conversion plays an important role in many applications such as communication,sensing,and *** signal conversion between optical and microwave frequencies is a crucial step to construct hybrid communication systems that combine both optical and microwave wireless technologies to achieve better features,which are highly desirable in the future wireless ***,such a signal conversion process typically requires a complicated relay to perform multiple operations,which will consume additional hardware/time/energy ***,we report a light-to-microwave transmitter based on the time-varying and programmable metasurface integrated with a high-speed photoelectric detection circuit into a *** a transmitter can convert a light intensity signal to two microwave binary frequency shift keying signals by using the dispersion characteristics of the metasurface to implement the frequency division *** illustrate the metasurface-based transmitter,a hybrid wireless communication system that allows dual-channel data transmissions in a light-to-microwave link is demonstrated,and the experimental results show that two different videos can be transmitted and received simultaneously and *** metasurface-enabled signal conversion solution may enrich the functionalities of metasurfaces,and could also stimulate new information-oriented applications.

关键词： microwave surface light

Oxidation behavior of high Hf nickel-based superalloy in air at 900, 1000 and 1100℃

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International Journal of Minerals,Metallurgy and Materials 2021年第12期28卷 1957-1965页

作者： Jiu-han Xiao Ying Xiong Li Wang xiang-wei jiang Dong Wang Kai-wen Li Jia-sheng Dong Lang-hong Lou Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China China National South Aviation Industry Company Limited Zhuzhou 412002China

To investigate the oxidation behavior of a nickel-based superalloy with high hafnium content(1.34 wt%),this study performed isothermal oxidation tests at 900,1000,and 1100℃for up to 200 h.X-ray diffraction and scanning electron microscopy with energy-dispersive X-ray spectroscopy were applied to study the oxidation *** weight gain of the high Hf nickel-based superalloy exhibited a parabolalike curve,and no spallation of the oxide scale was observed during the oxidation *** alloy presented excellent oxidation resistance,and no HfO_(2) was observed in the oxide scale at 900℃.With the increase of the oxidation temperature to 1000℃,HfO_(2) particles formed in the spinel phases of the scale,and"peg-like"HfO_(2) was observed within and beneath the inner layer of Al2O_(3) after *** the oxidation temperature rose to 1100℃,"peg-like"HfO_(2) was observed at the early stage of the oxidation test(within 25 h).The formation mechanism of HfO_(2) and its impact on oxidation resistance were investigated based on the analysis of the oxidation test results at different temperatures.

关键词： superalloy resistance alloy

Dendritic branching patterns in platforms of complex Ni-based single crystal castings

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China Foundry 2019年第2期16卷 110-117页

作者： Min Huang Gong Zhang Dong Wang Zhi-cheng Ge Yu-zhang Lu xiang-wei jiang Lang-hong Lou Institute of Metal Research Chinese Academy of Sciences University of Chinese Academy of Sciences

Dendritic branching patterns at variable cross-sections in Ni-based single crystal(SX) castings of different generations were investigated using optical microscope(OM), electro probe microanalyzer(EPMA),differential scanning calorimeter(DSC), Thermo-Cal software and Pro-CAST software. Results show that the dendritic branching patterns are similar in outward platform in SXs of different generations. That is, the primary dendrites(PDs) are introduced into the platform by developing a series of secondary dendrites(SDs) to occupy the bottom of the platform, and the ternary dendrites(TDs) originating from these SDs grow upward to fill up the platform. With the SX generation increasing, the undercooling of melts in the inward platform increases significantly due to the increasing alloying elements and the segregation in the directional solidification(DS)process, and the growth velocity of the dendrite tip increases according to the dynamic model of dendrite growth,which is beneficial for the high-order dendrite development. The stronger dendritic branching ability is shown in the inward platform of the higher generation Ni-based SX.

关键词： dendritic branching patterns platform undercooling

Anisotropic coding metamaterials and their powerful manipulation of differently polarized terahertz waves

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Light(Science & Applications) 2016年第1期5卷 767-777页

作者： Shuo Liu Tie Jun Cui Quan Xu Di Bao Liangliang Du xiang Wan Wen Xuan Tang Chunmei Ouyang Xiao Yang Zhou Hao Yuan Hui Feng Ma wei xiang jiang Jiaguang Han weili Zhang Qiang Cheng State Key Laboratory of Millimeter Waves Southeast UniversityNanjing 210096China Synergetic Innovation Center of Wireless Communication Technology Southeast UniversityNanjing 210096China Cooperative Innovation Centre of Terahertz Science Chengdu 610054China Center for Terahertz Waves and College of Precision Instrument and Optoelectronics Engineering Tianjin UniversityTianjin 300072China jiangsu Xuantu Technology Co. Ltd.Nanjing 211111China

Metamaterials based on effective media can be used to produce a number of unusual physical properties(for example,negative refraction and invisibility cloaking)because they can be tailored with effective medium parameters that do not occur in ***,the use of coding metamaterials has been suggested for the control of electromagnetic waves through the design of coding sequences using digital elements‘0’and‘1,'which possess opposite phase *** we propose the concept of an anisotropic coding metamaterial in which the coding behaviors in different directions are dependent on the polarization status of the electromagnetic *** experimentally demonstrate an ultrathin and flexible polarization-controlled anisotropic coding metasurface that functions in the terahertz regime using specially designed coding *** encoding the elements with elaborately designed coding sequences(both 1-bit and 2-bit sequences),the x-and y-polarized waves can be anomalously reflected or independently diffused in three *** simulated far-field scattering patterns and near-field distributions are presented to illustrate the dual-functional performance of the encoded metasurface,and the results are consistent with the measured *** further demonstrate the ability of the anisotropic coding metasurfaces to generate a beam splitter and realize simultaneous anomalous reflections and polarization conversions,thus providing powerful control of differently polarized electromagnetic *** proposed method enables versatile beam behaviors under orthogonal polarizations using a single metasurface and has the potential for use in the development of interesting terahertz devices.

关键词： anisotropic metamaterial design coding metamaterial metasurface terahertz waves

Light-controllable time-domain digital coding metasurfaces

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Advanced Photonics 2022年第2期4卷 52-58页

作者： Xin Ge Zhang Ya Lun Sun Bingcheng Zhu wei xiang jiang Zaichen Zhang Tie Jun Cui Southeast University School of Information Science and EngineeringState Key Laboratory of Millimeter WavesNanjingChina Southeast University School of Information Science and EngineeringNational Mobile Communications Research LaboratoryNanjingChina Purple Mountain Laboratories NanjingChina Southeast University Frontiers Science Center for Mobile Information Communication and SecurityNanjingChina

Programmable metasurfaces enable real-time control of electromagnetic waves in a digital coding manner,which are suitable for implementing time-domain metasurfaces with strong harmonic manipulation ***,the time-domain metasurfaces are usually realized by adopting the wired electrical control method,which is effective and robust,but there are still some ***,we propose a light-controllable time-domain digital coding metasurface consisting of a full-polarization dynamic metasurface and a high-speed photoelectric detection circuit,from which the microwave reflection spectra are manipulated by time-varying light signals with periodic phase *** demonstrated,the light-controllable timedomain digital coding metasurface is illuminated by the light signals with two designed time-coding *** measured results show that the metasurface can well generate symmetrical harmonics and white-noise-like spectra,respectively,under such cases in the reflected *** proposed lightcontrollable time-varying metasurface offers a planar interface to tailor and link microwaves with lights in the time domain,which could promote the development of photoelectric hybrid metasurfaces and related multiphysics applications.

关键词： metasurface light-control time-domain metamaterial

Broadband diffusion of terahertz waves by multi-bit coding metasurfaces

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Light(Science & Applications) 2015年第1期4卷 207-215页

作者： Li-Hua Gao Qiang Cheng Jing Yang Shao-Jie Ma Jie Zhao Shuo Liu Hai-Bing Chen Qiong He wei-xiang jiang Hui-Feng Ma Qi-Ye Wen Lan-Ju Liang Biao-Bing Jin wei-wei Liu Lei Zhou Jian-Quan Yao Pei-Heng Wu Tie-Jun Cui State Key Laboratory of Millimeter Waves Department of Radio EngineeringSoutheast UniversityNanjing 210096China Cooperative Innovation Centre of Terahertz Science No.4Section 2North Jianshe RoadChengdu 610054China Institute of Modern Optics Key Laboratory of Optical Information Science and Technology(Ministry of Education)Nankai UniversityTianjin 300071China State Key Laboratory of Surface Physics Key Laboratory of Micro and Nano Photonic Structures(Ministry of Education)Department of PhysicsFudan UniversityShanghai 200433China State Key Laboratory of Electronic Films and Integrated Devices University of Electronic Science and TechnologyChengdu 610054China Research Institute of Superconductor Electronics(RISE) School of Electronic Science and EngineeringNanjing UniversityNanjing 210093China Institute of Lasers and Optoelectronics College of Precision Instrument and Opto-Electronics EngineeringTianjin UniversityTianjin 300072China

The terahertz region is a special region of the electromagnetic spectrum that incorporates the advantages of both microwaves and infrared light *** the past decade,metamaterials with effective medium parameters or gradient phases have been studied to control terahertz waves and realize functional ***,we present a new approach to manipulate terahertz waves by using coding metasurfaces that are composed of digital coding *** propose a general coding unit based on a Minkowski closed-loop particle that is capable of generating 1-bit coding(with two phase states of 0 and 180°),2-bit coding(with four phase states of 0,90°,180°,and 270°),and multi-bit coding elements in the terahertz frequencies by using different geometric *** show that multi-bit coding metasurfaces have strong abilities to control terahertz waves by designing-specific coding *** an application,we demonstrate a new scattering strategy of terahertz waves—broadband and wide-angle diffusion—using a 2-bit coding metasurface with a special coding design and verify it by both numerical simulations and *** presented method opens a new route to reducing the scattering of terahertz waves.

关键词： coding diffusion metasurface terahertz waves

Infrared-controlled programmable metasurface

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Science Bulletin 2020年第11期65卷 883-888,M0003页

作者： Ya-Lun Sun Xin-Ge Zhang Qian Yu wei-xiang jiang Tie-Jun Cui State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast UniversityNanjing 210096China

Programmable metasurface enables controlling electromagnetic (EM) waves in real time. By programming the states of active device embedded in metasurface element, the EM properties of the digital metasurface can be changed quickly without redesigning their structures. However, large numbers of long-distance wires are required to connect the programmable metasurface to provide the coded signals from field programmable gate array (FPGA) when controlling the metasurface at a long distance, which is complicated and inconvenient. Here, we propose an infrared-controlled programmable metasurface that can be programmed remotely. The infrared transceiver is able to switch the coding sequences stored in the FPGA controller, thus controlling the voltage on the varactors integrated in the metasurface. Experiment is performed at microwave frequencies, and the measured results verify that the scattering beams of the metasurface sample can be changed remotely by using infrared ray. The proposed infrared-controlled programmable metasurface opens up avenues for constructing a new class of remotely-tuning dynamic metasurfaces.

关键词： Infrared-controlled programmable metasurfaces Remotely-tuning Beam splitting Beam scanning

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光伏水泵系统的最大功率点跟踪器

太阳能学报 1991年第3期12卷 225-230页

作者：余世杰战福忠沈维祥姜跃炜合肥工业大学能源研究所

本文扼要地介绍了配有最大功率点跟踪器(MPPT)的光伏水泵系统,并就MPPT的原理及实现方法进行了讨论,最后指出了最大功率点跟踪器对光伏水泵系统的影响。

关键词：光伏水泵功率点跟踪器水泵