State-dependent event-triggered control of multi-agent systems

Event-triggered control has been recent/y proposed as an effective strategy for the consensus of multi-agent systems. We present an improved distributed event-triggered control scheme that remedies a shortcoming of some previous event- triggered control schemes in the literature. This improved distributed event-triggered method has no need for continuously monitoring each agent＇ neighbors. Moreover, each agent in the multi-agent systems will not exhibit the Zeno behavior. Numerical simulation results show the effectiveness of the proposed consensus control.     

风云二号辐射计百叶窗式遮光罩杂散光抑制研究

风云二号卫星扫描辐射计为视场分光方式的R-C光学系统,视场外的杂光掠过次镜穿过主镜孔直接混入信号光路照射在焦面上,形成直射杂光。为了消除该直射杂光,使用TracePro软件对辐射计模型进行正追和倒追,都追到了直射杂光的存在,利用Zemax软件仿真找出了该直射杂光的形成机理,并计算出该直射杂光域。根据仿真和计算,设计了可以透信号光阻挡杂散光的叶片状次镜遮光罩。软件仿真表明：百叶窗式遮光罩可以彻底抑制该区域可见直射杂光,积分球实验也验证了该百叶窗式遮光罩可以降低辐射计952%的可见杂光。     

二维等离子体填充金属光子晶体腔体特性

设计了等离子体填充的二维金属光子晶体特殊开放腔体结构,并采用粒子模拟技术(PIC)建立了基于等离子体填充腔体结构物理模型,分析了等离子体填充下二维腔体的各模式场分布特性,以及等离子体的引入对腔体内各模式工作频率、电场幅值的影响。结果表明:腔体内各模式的电场强度随等离子体密度的增加而减弱,模式频率随背景等离子体归一化频率的提高而增加,工作模式的产生与激励方式密切相关。     

Changes in Repetitive Firing Rate Related to Phase Response Curves for Andronov-Hopf Bifurcations

We study specific changes in repetitive firing in the two-dimensional Hindmarsh-Rose （2dHR） oscillatory sys- tem that undergoes a bifurcation transition from the supercritical Andronov-Hopf （All） type to the subcritical Andronov-Hopf （SAH） type. We identify dynamical mechanisms which are responsible for changes of the repeti- tive firing rate during the AH to SAH bifurcation transitions. These include frequency-shift functions in response to small perturbations of a timescale parameter, its multiplicative parameter, and an external input current in the 2dHR oscillatory system. The frequency-shift functions are explicitly represented as functions relating to the phase response curves （PRCs）. Then, we demonstrate that when the timescale is normal and relatively fast, the repetitive firing rate slightly increases and decreases respectively during the AH to SAH bifurcation transition with a change of the intrinsic parameter, whereas it decreases during the SAH to AH bifurcation transition with an increase in the timescale. By analyzing the three different frequency-shift functions, we show that such changes of the repetitive firing rate depend largely on changes of the PRC size. The PRC size for the SAH bifurcation shrinks to the PRC size for the AH bifurcation.     

基于压扩变换的60GHz正交频分复用光载无线通信系统实验研究

提出并实验研究了在60GHz正交频分复用(OFDM)-光载无线通信(ROF)系统中采用压扩变换技术降低OFDM信号峰值平均功率比(PAPR),并提高系统的接收灵敏度。实验结果表明,携带基于压扩变换的2.5Gb/s60GHz的OFDM-ROF信号经标准单模光纤传输50km后,在无色散补偿和误码率为10-3的条件下,当入纤功率为12dBm时,系统接收灵敏度提高约2.3dB,并且当互补累积分布函数(CCDF)为10-4时,OFDM信号的PAPR下降约3dB。     

多组全动型变焦系统新型设计

为了寻找简单的多组全动型变焦系统的解算方法及降低全动型变焦距系统设计时对经验的过分依赖,提出了一种全新的方法来计算系统组元的光焦度分配。以组元之间的间隔为初始量,把组元的运动形式作为自由量,通过计算公式求出满足间隔要求的光焦度分配和组元运动形式。该方法在一定程度上降低了变焦系统光焦度分配的难度,更重要的是,为探寻新的变焦运动方式提供了一种新的思路。在得到系统的光焦度分配之后又推导出一种求解系统组元移动曲线的简单方法。为了验证该方法的可行性,设计了一个四组式全动型变焦系统。所设计系统优化后的光焦度分配值和计算的结果都很接近,并且得到了组元的移动曲线,从而验证了该方法的正确性。     

近红外微型光谱仪光学系统设计与模拟

基于光谱仪基本工作原理和光学设计理论,以系统微型化、且能满足一定光谱范围和分辨率要求为具体设计目标,提出了基于平面衍射光栅分光的交叉式C-T结构的近红外微型光谱仪光学系统结构方案。采用ZEMAX软件对近红外微型光谱仪的分光系统、成像系统进行了优化设计与模拟分析。最终设计与模拟分析结果表明,该光学系统光谱范围为900～1 700 nm,分辨率<10 nm,谱面展宽为12.74 mm,F数为8.128 388,系统体积为51.26 mm×41.81 mm×22 mm。     

Influence of laser mode on splitting beam illumination effect of Dammann grating

The influences of various laser modes on the splitting beam effect of Dammann grating are studied in theory and by numerical simulation. The results show that fundamental mode laser resembles plane wave while high order mode laser differs from plane wave in the splitting beam effect by Dammann grating. Therefore, the fundamental mode laser is more suitable to be the light source to improve the energy efficiency in far-distance image detecting systems, such as laser image ladar, which use Dammann grating in the ilhlmination svstem.     

Branch Processes of Regular Magnetic Monopole

In this paper, by making use of Duan＇s topological current theory, the branch process of regular magnetic monopoles is discussed in detail. Regular magnetic monopoles are found generating or annihilating at the limit point and encountering, splitting, or merging at the bifurcation point and the degenerate point systematically of the vector order parameter field φ（x）. Furthermore, it is also shown that when regular magnetic monopoles split or merge at the degenerate point of field function φ, the total topological charges of the regular magnetic monopoles are stilI unchanged.     

A Criterion for Stability of Synchronization and Application to Coupled Chua＇s Systems

We investigate synchronization in an array network of nearest-neighbor coupled chaotic oscillators. By using of the Lyapunov stability theory and matrix theory, a criterion for stability of complete synchronization is deduced. Meanwhile, an estimate of the critical coupling strength is obtained to ensure achieving chaos synchronization. As an example application, a model of coupled Chua＇s circuits with linearly bidirectional coupling is studied to verify the validity of the criterion.