Adaptive lag synchronization of uncertain dynamical systems with time delays via simple transmission lag feedback

In this paper we present an adaptive scheme to achieve lag synchronization for uncertain dynamical systems with time delays and unknown parameters. In contrast to the nonlinear feedback scheme reported in the previous literature, the proposed controller is a linear one which only involves simple feedback information from the drive system with signal popagation lags. Besides, the unknown parameters can also be identified via the proposed updating laws in spite of the existence of model delays and transmission lags, as long as the linear independence condition between the related function elements is satisfied. Two examples, i.e., the Mackey-Glass model with single delay and the Lorenz system with multiple delays, are employed to show the effectiveness of this approach. Some robustness issues are also discussed, which shows that the proposed scheme is quite robust in switching and noisy environment.     

测量时间分辨拉曼谱实验装置的研制

测量时间分辨拉曼谱实验装置的研制王晶晶金榕周赫田邹英华（北京大学物理系人工微结构及介观物理国家重点实验室北京１００８７１）孙志勇（北京理工大学四系４３１教研室北京１０００８１）ＴｈｅＥｘｐｅｒｉｍｅｎｔａｌＳｅｔｕｐｆｏｒＴｉｍｅ－ＲｅｓｏｌｖｅｄＲ...     

核磁共振法测定苯基硅橡胶的苯基、乙烯基

采用核磁定量技术测定苯基硅橡胶苯基、乙烯基的含量,研究了氘代溶剂种类、脉冲角度、弛豫延迟时间等参数对测定结果的影响。结果表明,氘代氯仿的溶剂峰与苯基共振峰重叠,导致苯基含量测定结果偏高;手动校正谱图相位、基线得到的测定结果波动小;在3～24 s范围内,信噪比随着弛豫延迟时间的增加呈下降趋势;信噪比随着采样时间、扫描次数增加而增大。确定的实验条件:溶剂为氘代四氢呋喃,脉冲偏转角为30°,采样次数为128,采样时间为3 s,弛豫延迟时间为3 s,手动校正谱线。稳定性试验结果的离散系数为0.71%～1.9%(n=5)。用该方法对高纯度甲基苯基环硅氧烷的苯基及甲基乙烯基环硅氧烷中的乙烯基含量进行测试,测定结果分别为100.074%,98.538%,均接近理论值(100%),测定结果的相对标准偏差为0.06%,0.08%(n=5)。该方法稳定性好,精确度良好,可用于苯基硅橡胶苯基、乙烯基含量的测定。     

A general method for synchronizing an integer-order chaotic system and a fractional-order chaotic system

This paper investigates the synchronization between integer-order and fractional-order chaotic systems.By intro-ducing fractional-order operators into the controllers,the addressed problem is transformed into a synchronization one among integer-order systems.A novel general method is presented in the paper with rigorous proof.Based on this method,effective controllers are designed for the synchronization between Lorenz systems with an integer order and a fractional order,and for the synchronization between an integer-order Chen system and a fractional-order Liu system.Numerical results,which agree well with the theoretical analyses,are also given to show the effectiveness of this method.     

工程模型常用检验方法及应用实例

描绘变量间统计关系的数学模型是近似公式,其正确性与精度必须通过统计检验验证.统计检验的方法很多且各具优势,着重介绍土建工程变形分析中常用的相关性检验、T检验、χ2检验等,并佐以实例阐明应用范围和具体推演方式,旨在运用经典数学理论指导施工控制,实现数学理论与工程实践的成功结合.     

苯甲醛缩氨基脲铜（II）配合物为载体的高选择性硫氰酸根离子电极的研究

首次研究以苯甲醛缩氨基脲铜（II）[Cu(II)-BASA]为中性载体的PVC膜电极， 该电极对硫氰酸根离子（SCN~-）具有优良的电位响应特性并呈现出反Hofmeister 选择性行为，其选择性次序为：SCN~- > ClO_4~- > I~- > Sal~- > Br~- > NO_3~- > Cl~- > NO_2~- > SO_3~(2-) > SO_4~(2-) > H_2PO_4~-。电极在pH 6. 0的磷酸盐缓冲体系中，对SCN~-在1.0 * 10~(-1)～8.0 * 10~(-6) mol/L浓度范围 内呈近能斯特响应，斜率为56.0 mV/sSCN~- (28 ℃)，检测下限为3.0 * 10~(-6) mol/L。采用交流阻抗技术和紫外可见光谱技术初步研究了阴离子与载体的作用机 理，结果表明配合物中心金属原子的结构以及载体本身的结构与电极的响应行为之 间有非常密切的构效关系。该电极具有响应快、重现性好、检测限低、制备简单等 优点。将电极初步应用于实际样品废水分析，结果与HPLC法一致。     

以苯甲醛缩硫代氨基脲铜(Ⅱ)配合物为载体的高选择性硫氰酸根离子电极的研究

本文研究了以苯甲醛缩硫代氨基脲铜(Ⅱ)[Cu(Ⅱ)-BATA]为中性载体的PVC膜电极。发现该电极对SCN-具有优良的电位响应特性,并呈现反Hofmeister选择性行为。采用紫外可见光谱法研究了阴离子与载体的作用机理,并将该电极初步应用于实际废水样品分析,结果满意。     

Simultaneous identification of unknown time delays and model parameters in uncertain dynamical systems with linear or nonlinear parameterization by autosynchronization

In this paper, we propose a general method to simultaneously identify both unknown time delays and unknown model parameters in delayed dynamical systems based on the autosynchronization technique. The design procedure is presented in detail by constructing a specific Lyapunov function and linearizing the model function with nonlinear parameterization. The obtained result can be directly extended to the identification problem of linearly parameterized dynamical systems. Two Wpical numerical examples confirming the effectiveness of the identification method are given.     

ZigBee技术在塔吊安全监测预警系统中的应用

针对建设工程塔吊安全监测的现状,将ZigBee技术应用于塔吊安全监测预警系统,设计专用WSN节点,实现位移、压力和距离监测功能;将现场监测数据通过WSN节点及时上传到监控中心PC机进行实时显示和处理,如果监测数据超出报警值,立即发出报警信号,从而有效地预防塔吊事故发生,确保塔吊运行安全;经组网调试,系统性能稳定可靠,测量数据误差小于5%,传输距离可达1 km 以上,具有较高的性价比和推广应用价值。     

双呋喃甲醛丙二胺席夫碱铜(Ⅱ)络合物为载体的选择性碘离子电极的研究

以易于制备的3种二醋酸双(呋喃甲醛)缩1,3-丙二胺铜(Ⅱ)、钴(Ⅱ)、锰(Ⅱ)金属络合物为载体制备了阴离子选择性电极,发现以二醋酸双(呋喃甲醛)缩1,3—丙二胺Ca(Ⅱ）[Cu(Cu（Ⅱ）—BFADP]络合物为载体的PVC膜电极能明显改善对I^-的响应。采用紫外光谱分析技术和交流阻抗技术研究了电极对I^-响应机理,并将电极初步应用于药品分析,结果令人满意。