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Piecewise linear recursive convolution FDTD method for magnetized plasmas

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Journal of Systems Engineering and Electronics 2006年第2期17卷 290-295页

作者： liu Song Zhong Shuangying liu shaobin School of Sciences Nanchang Univ. Nanchang 330047 P. R. China

The piecewise linear recursive convolution （PLRC） finite-different time-domain （FDTD） method greatly improves accuracy over the original recursive convolution （RC） FDTD approach but retains its speed and efficiency advantages. A PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time is presented, enabled the transient analysis of magnetized plasma media. The technique is illustrated by numerical simulations the reflection and transmission coefficients through a magnetized plasma layer. The results show that the PLRC-FDTD method has significantly improved the accuracy over the original RC method.

关键词： electromagnetic wave FDTD methods piecewise linear recursive convolution magnetized plasma.

Wentzel-Kramer-Brillouin and finite-difierence time-domain analysis of Terahertz band electromagnetic characteristics of target coated with unmagnetized plasma

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Journal of Systems Engineering and Electronics 2008年第1期19卷 15-20页

作者： liu shaobin Zhou Tao liu Meilin Hong Wei State Key Lab. of Millimeter Waves Southeast Univ. Nanjing 210096 P. R. China Coll. of Information Science &: Technology Nanjing Univ. of Aeronautics & Astronautics Nanjing 210016 P. R. China

We investigate computationally the attenuation and reflection of Terahertz （THz） wave using targets coated with plasmas. The simulators are the Wentzel-Kramer-Brillouin （WKB） method and finite-difference timedomain （FDTD） method. The relation between the frequency of the incident electromagnetic （EM） wave and the attenuation caused by unmagnitized plasma is analyzed. The results demonstrate that the amount of absorbed power is a decreasing function of the EM wave frequency and the plasma collision frequency. For THz band incident wave, the attenuation that is caused by plasma is small when the plasma has common density and the collision frequency. This conclusion has fine applying foreground for plasma anti stealth.

关键词： frequency dispersion WKB method FDTD methods unmagnetized plasma Terahertz wave

Auto-scalable and fault-tolerant load balancing mechanism for cloud computing based on the proof-of-work election

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Science China(Information Sciences) 2022年第1期65卷 131-146页

作者： Xiaoqin FENG Jianfeng MA shaobin liu Yinbin MIAO Ximeng liu School of Cyber Engineering Xidian University State Key Laboratory of Cryptology Shaanxi Key Laboratory of Network and System Security Xidian University College of Mathematics and Computer Science Fuzhou University

Load balancing mechanism in technologies such as cloud computing has provided a huge opportunity for the development of large-scale projects. Although the conventional view is to build mechanisms that adopt a dynamic load balancing strategy, existing strategies cannot automatically scale platform(network) servers(nodes) to adapt for dynamic requests, but only guarantee load balancing for the pre-deployed nodes, thereby increasing resource consumption and decreasing networks’ efficiency. We contend that existing load balancing mechanisms are inadequate for deploying dynamic applications. In this regard, we first adopt both load balancing and cloud computing virtualization technologies to modularly design a load balancing mechanism that provides a dynamically auto-scalable solution for large-scale and dynamic computing scenarios. Furthermore, we adopt the proof-of-work consensus, for a novel use during the lifecycle of master nodes in case of system failure caused by a failed master node, to demonstrate a fault-tolerant load balancing mechanism. We theoretically evaluate the security requirement of our mechanism and analyze its performance. Experimental results show that the mechanism supports auto-scalability and has a better performance compared to existing mechanisms such as the ordinary cluster.

关键词： cloud computing load balancing auto-scalable proof-of-work fault-tolerant

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Numerical study on the modulation of THz wave propagation by collisional microplasma photonic crystal

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Plasma Science and Technology 2020年第11期22卷 42-51页

作者： Shuqun WU Yuxiu CHEN Minge liu Lu YANG Chaohai ZHANG shaobin liu College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016People's Republic of China College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016People's Republic of China

In order to demonstrate the modulation of terahertz wave propagation in atmospheric pressure microplasmas,in this work,the band structure and the transmission characteristics of a onedimensional collisional microplasma photonic crystal are investigated,using the transfer matrix *** a lattice constant of 150μm and a plasma width of 100μm,three stopbands of microplasma photonic crystal are observed,in a frequency range of 0.1-5 ***,an increase in gas pressure leads to a decrease in the central frequency of the *** the gas pressure increases from 50.5 k Pa to 202 k Pa,the transmission coefficient of the THz wave first increases and then decreases at high frequency,where the wave frequency is much greater than both the plasma frequency and the collision ***,it is interesting to find that the central frequency and the bandwidth of the first THz stopband remain almost unchanged for electron densities of less than 10^15 cm^-3,increasing significantly when the electron density increases up to 10^16 cm^-3.A central frequency shift of 110 GHz,and a bandgap broadening of 200 GHz in the first stopband are *** addition,an atmospheric pressure microplasma with the electron density of 1×10^15-6×10^15 cm^-3 is recommended for the modulation of THz wave propagation by plasma photonic crystals.

关键词： microplasma plasma photonic crystal terahertz wave electron density

Flexible broadband polarization converter based on metasurface at microwave band

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Chinese Physics B 2019年第7期28卷 243-251页

作者： Qi Wang Xiangkun Kong Xiangxi Yan Yan Xu shaobin liu Jinjun Mo Xiaochun liu Key Laboratory of Radar Imaging and Microwave Photonics Ministry of Education College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing 211106 China School of Aeronautics and Astronautics Central South University Changsha 410083 China Research Institute for Special Structures of Aeronautical Composite Aviation Industry Corporation of China Aeronautical Science Key Laboratory for High Performance Electromagnetic Windows Jinan 250000 China

A flexible broadband linear polarization converter is proposed based on the metasurface operating at microwave *** achieve bandwidth extension property, long and short metallic arc wires, as well as the metallic disks placed over a ground plane, are combined into the polarizer, which can generate three neighboring *** to the combination of the first two resonances and the optimized size and thickness of the unit cell, the polarization converter can have a weak incident angle *** simulated and measured results confirm that the average polarization conversion ratio is over 85% from 11.3 GHz to 20.2 GHz within a broad range of incident angle from 0°to 45°.Moreover, the proposed polarization converter based on flexible substrates can be applied for conformal *** simulation and experiment results demonstrate that our designed polarizer still keeps high polarization conversion efficiency, even when it adheres to convex cylindrical *** periodic metallic structure of the designed polarizer has great potential application values in the microwave, terahertz, and optic regimes.

关键词： polarization converter flexible metasurface wide-angle broadband

A novel polarization converter based on the band-stop frequency selective surface

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Chinese Physics B 2022年第2期31卷 380-386页

作者： Kun Liao Shining Sun Xinyuan Zheng Xianxian Shao Xiangkun Kong shaobin liu College of Electronic and Information Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Aviation Key Laboratory of Science and Technology on High Performance Electromagnetic Windows Jinan 250023China Pingxiang Health Vocational College Pingxiang 337006China

A dual-passband single-polarized converter based on the band-stop frequency selective surface(FSS)with a low radar cross-section(RCS)is designed in this *** unit cell of the proposed converter is formed by a polarization layer attached to the band-stop frequency selective *** simulation results reveal that the co-polarization reflection coefficients below-10 d B are achieved in 3.82–13.64 GHz with a 112.4%fractional bandwidth(the ratio of the signal bandwidth to the central frequency).Meanwhile,a polarization conversion band is realized from 8.14 GHz to 9.27 GHz with a polarization conversion ratio which is over 80%.Moreover,the 1 d B transmission window is obtained in two nonadjacent bands of 3.42–7.02 GHz and 10.04–13.91 GHz corresponding to the relative bandwidths of 68.9%and 32.3%,***,the radar cross-section of the designed structure can be reduced in the wideband from 2.28 GHz to 14 GHz,and the 10 d B RCS reduction in the range of 4.10–13.35 GHz is *** addition,the equivalent circuit model of this converter is established,and the simulation results of the Advanced Design System(ADS)match well with those of CST Microwave Studio(CST).The archetype of the designed converter is manufactured and *** experiment results match the simulation results well,which proves the reliability of the simulation results.

关键词： dual-passband single-polarized converter polarization radar cross-section(RCS)

等离子体覆盖目标散射特性的RKETD-FDTD分析

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南京航空航天大学学报 2009年第4期41卷 532-535页

作者：刘崧刘少斌南京航空航天大学信息科学与技术学院南京210016 南昌大学理学院南昌330031

采用一种既保证计算的高效率,又有较高的计算精度的龙格库塔指数时程差分时域有限差分法(RKETD-FDTD)研究了等离子体的散射特性。该算法解决了电磁波在色散介质中传播的计算问题,导出了在等离子体介质中RKETD-FDTD迭代公式。文中分别计... 详细信息

采用一种既保证计算的高效率,又有较高的计算精度的龙格库塔指数时程差分时域有限差分法(RKETD-FDTD)研究了等离子体的散射特性。该算法解决了电磁波在色散介质中传播的计算问题,导出了在等离子体介质中RKETD-FDTD迭代公式。文中分别计算了等离子体平板的反射系数和非均匀等离子体覆盖导体柱的散射特性,所得结果与解析结果相符合,并且表明等离子体涂层选择合适的碰撞频率,能有效地减小目标的雷达散射截面(RCS)。

关键词：等离子体散射特性时域有限差分法电磁波

Broadband and conformal metamaterial absorber

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Frontiers of Optoelectronics 2017年第2期10卷 124-131页

作者： Xiangkun KONG Junyi XU Jin-jun MO shaobin liu Key Laboratory of Radar Imaging and Microwave Photonics Ministry of Education College of Electronic and Information Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016 China State Key Laboratory of Millimeter Waves Southeast University Nanjing 210096 China College of Electronic Science and Engineering National University of Defense Technology Changsha 410073 China

In this study, a new broadband and conformal metamaterial absorber using two flexible substrates was proposed. Simulation results showed that the proposed absorber exhibited an absorption band from 6.08 to 13.04 GHz and a high absorption of 90%, because it was planar. The absorber was broadband as its relative absorption bandwidth was 72.8%. Moreover, the proposed absorber was insensitive to the polarization of the TE and TM waves. The absorber was ultra-thin; its total thickness was only 0.072 at the lowest operating frequency. Furthermore, different regions of absorption can be adjusted by lumping and loading two resistors onto the polyimide film, respectively. Moreover, compared with the conventional microwave absorber, the absorption bandwidth of the proposed absorber can be broadened and enhanced when it was bent and conformed to the surface of objects. Experimental and simulation results were in agreement. The proposed absorber is a promising absorbing element in scientific and technical applications because of its broad- band absorption, polarization insensitivity, and flexible substrates.

关键词： absorber metamaterials flexible broadband,conformal

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主体结构位移激励下碳纤维索桁架非线性振动

机械强度 2011年第3期33卷 334-338页

作者：刘少斌湖南文理学院土木建筑工程学院常德415000

研究碳纤维材料索桁架在主体结构位移激励下的非线性振动问题,是空间索结构抗震防震设计的基础。在考虑温度变化的基础上,建立碳纤维索桁架在主体结构位移激励下的非线性振动方程,采用Galerkin原理及Krylov-Bogol-iulov-Mitropolsky法... 详细信息

研究碳纤维材料索桁架在主体结构位移激励下的非线性振动问题,是空间索结构抗震防震设计的基础。在考虑温度变化的基础上,建立碳纤维索桁架在主体结构位移激励下的非线性振动方程,采用Galerkin原理及Krylov-Bogol-iulov-Mitropolsky法求得碳纤维材料索桁架非线性振动的近似解。在将碳纤维索网与钢丝索网比较的基础上,讨论分析温度、位移激励、振幅、阻尼等因素对索桁架非线性振动的影响,得到碳纤维索桁架振动特性优于钢丝索桁架振动特性的结论。

关键词：主体结构位移激励碳纤维索桁架