Finite-time stabilization of state dependent impulsive dynamical linear systems

The problem of finite-time stabilizing control design for state-dependent impulsive dynamical linear systems (SD-IDLS) is tackled in this paper. Such systems are characterized by continuous-time, linear, possibly time-varying, dynamics coupled with discrete-time, linear, possibly time-varying, dynamics. The continuous-time part determines the system evolution in any time interval between two consecutive resetting events, while the discrete-time part governs its instantaneous state jump whenever the system trajectory intersects a resetting set, i.e. a region of the state space assumed to be time-independent. By making use of a quadratic control Lyapunov function, the finite-time stabilization of SD-IDLS through a static output feedback control design is specifically discussed in this paper. A sufficient and constructive result is provided based on the conical hulls of the resetting set subregions and on some cone copositivity properties of the chosen control Lyapunov function. Such a result is based on the solution of a feasibility problem that involves a set of coupled Difference/Differential Linear Matrix Inequalities (D/DLMI), which is shown to be less conservative and more numerically amenable with respect to other results available in the literature. An example illustrates the effectiveness of the proposed approach.     

行波管内不连续性的简易模型分析

 根据行波管内微波信号在输能装置和切断衰减器处两个不连续性之间来回反射的物理现象,建立行波管输出段的简易网络串模型,并对行波管输出段传输特性参数的幅频特性、相频特性进行计算分析。结果表明：输能装置和切断衰减器的不连续性是造成幅相一致性行波管相位不可补偿的重要因素之一。     

不确定离散模糊随机系统的鲁棒方差约束输出反馈控制

对一类具有范数有界不确定性的离散T-S模糊随机系统。研究不仅使整个闭环模糊系统全局渐近稳定。而且每个模糊子系统的稳态状态方差满足给定上界性能指标约束的输出反馈鲁棒方差控制律的设计问题。利用线性矩阵不等式(LMI)技术,导出输出反馈鲁棒方差控制律的存在条件,并基于矩阵相似变换给出其可解性条件,同时用一组线性矩阵不等式的可行解。给出输出反馈鲁棒方差控制律的一个参数化表达形式。     

回旋速调管放大器输出腔的特性研究

 利用变截面波导的耦合模理论,根据输出腔中电场幅值分布函数所满足的微分方程组,编写了具有自动优化功能的计算程序,分析研究了不同渐变角度、考虑腔体损耗前后和输出腔与外电路失配时,谐振频率、腔体品质因数和高频场幅值沿轴分布的变化情况,为进一步研究高频场与电子注的互作用和输出腔奠定了基础。     

Passive Attitude Control of Flexible Spacecraft from Quaternion Measurements

In this work, we propose a dynamic controller for a spacecraft with flexible appendages and based on attitude measurements. This control ensures the asymptotic fulfillment of the objectives in the case of rest-to-rest maneuvers when a failure occurs on the accelerometer sensors, so that the angular velocity is not available for feedback. Also, it is assumed that the modal variables describing the flexible elements are not measured. This is a lower level controller and is to be selected at the higher level by a supervisor when an emergency situation is detected.     

A 1.2 to 6 keV soft X-ray beamline at Beijing Synchrotron Radiation Facility

A new soft X-ray beamline with double-crystal monochromator and double direction focus has been constructed at Beijing Synchrotron Radiation Facility (BSRF). The beamline covers the soft X-ray energy range from 1.2 keV up to 6 keV. There are three pairs of crystals (Si (111), InSb (111), KTP(011)) for the monochromator, separately. The performance of the crystals in respect to flux, resolving power and higher orders is discussed, and some representative results from the beamline are given. The beamline is used for a variety of experiments, for example, calibration detector, measurements of optics element characteristics and soft X-ray spectroscopy (SXS).     

专利资产证券化研究

专利证券化是一种新型的融资方式,它借助于资产证券化为专利权人融得发展所需的资金。与传统资产证券化相比,它有自己的特点。由于资产证券化的发展以及专利量越来越大,我国已具有专利证券化的条件,具备实行专利证券化的可行性。     

Adaptive robust fuzzy control for a class of uncertain chaotic systems

In this paper, the output feedback control of uncertain chaotic systems is addressed via an adaptive robust fuzzy approach. Fuzzy logic systems are employed to approximate uncertain nonlinear functions in the chaotic systems. Because only partial information of the system’s states is needed to be known, an observer is given to estimate the unmeasured states. Compared with the existing results in the observer design, the prior knowledge on dynamic uncertainties is relaxed and a class of more general chaotic systems is considered as well as robustness to the approximation error is improved. It can be proven that the closed-loop system is stable in the sense that all the variables are bounded. Simulation example for the unified chaotic systems is given to verify the effectiveness of the proposed method. This work was supported in part by the National Natural Science Foundation of China (60874056) and the Foundation of Educational Department of Liaoning Province (2008312).     

多注速调管π模双间隙腔截止波导输出回路研究

 用数值模拟的方法研究了多注速调管π模双间隙腔加载截止波导两节滤波器型输出回路的特性,并重点研究了π模双间隙腔与截止段的耦合结构对输出腔间隙阻抗频率特性的影响,以及耦合接头和电容性销钉对截止波导滤波器的调谐作用。研究结果表明：π模双间隙腔连接截止波导段的耦合口的尺寸主要影响输出腔的外观品质因数,而耦合接头的粗细和电容性销钉的大小和插入深度对截止波导滤波器的调谐具有重要影响。另外,由于耦合接头相当于在截止段中引入了一个附加电感,这使滤波器谐振电路的品质因数变大,谐振峰变窄。因此,π模双间隙腔加载截止波导滤波器型输出回路并不比单间隙腔加载截止波导滤波器型输出回路有更好的带宽优势。     

三模重叠双间隙耦合腔型输出回路的仿真设计

 为扩展速调管输出回路的带宽,进一步分析了双间隙耦合腔的模式重叠理论,说明了实现三模重叠的可能性,采用等效电路法计算了三模重叠双间隙耦合腔型输出回路的阻抗频率特性。以中心频率3 GHz的输出回路为例,建立了3维计算模型,给出了设计这种输出回路的步骤和结构参数。用场分析法计算了间隙阻抗频率特性,结果表明：此输出回路2 dB相对带宽接近15%,加载滤波器后1.5 dB相对带宽可达19.3%。