Experimental Investigation of Chaos Synchronization in DFB Diode Lasers with Unsymmetrical Scheme

We experimentally generate high dimension chaotic waveforms with smooth spectrum using a distributed feedback （DFB） semiconductor laser with unidirectional fibre ring long-cavity feedback, and implement the stable chaos synchronization when the chaotic light is injected into a solitary DFB laser diode. The synchronization quality is investigated by time-domain and frequency-domain analysis separately, The frequency-domain analysis indicates that the synchronization has higher quality in the high frequency band. The influences of the injection strength and the frequency detuning on the synchronization are measured. Our experimental results show that the robust synchronization can be maintained with the optical frequency detuning from -11GHz to 40 GHz.     

利用复原电压预测大气湍流畸变波前方法

 在校正大气湍流畸变信号的自适应光学系统中，基于大气开环数据，对采用最小递归二乘RLS算法预测复原电压以减小自适应光学系统中的时间伺服延迟进行了仿真研究。并与未采用预测时的误差进行了比较，对比结果表明：采用RLS算法后，可以有效的降低系统由伺服延迟引起的误差。     

锰矿中铁、锌、铅的连续示波极谱快速测定

本文解决了长期以来存在的氨性底液中Zn~(2+)与Co~(2+)、Bi~(3+)与Pb~(2+)的两种干扰问题,提出了加入氨三乙酸的氨溶液(NTA-NH_3)和抗坏血酸(VC)使矿样不经任何分离即可直接在CU~(2+)、Bi~(3+)、Ni~(2+)、Co~(2+)、Cd~(2+)、Sb~(2+)和大量Mn~(2+)存在下,在(NH_4)_2CO_3-NH_3底液中连续快速测定Fe~(3+)、Zn~(2+)、Pb~(2+)的新方法。即使Fe~(3+)含量比Pb~(2+)大200倍也能顺利测Pb~(2+)。如Sb~(3+)不存在可连续测Cd~(2+)。若Zn~(2+)、Co~(2+)含量相差不大,则溶解一个矿样后同时可用文献[1]的方法测Zn~(2+)和Co~(2+)的重合波作为Zn~(2+)、Co~(2+)总量,然后减去本法测定的Zn~(2+)含量,半定量估计Co~(2+)含量,并定量测定Cu~(2+)和Ni~(2+)。本法溶矿手续简便,用固体Na_2SO_3除氧,不需加极大抑制剂,测定手续几分钟内即完成,误差在允许范围以内。     

SENSITIVITY ANALYSIS OF TRUSS STRUCTURES AND ITS APPLICATION TO THE FULLY STRESSED DESIGN

Based upon the theorems of structural variations this paper derives a set of expressions for calculating partial derivatives of internal forces, stresses and joint displacements with respect to bar areas for truss structures. Compared with the known formulas for finding the gradients of structural behaviours the calculation effort with the proposed expressions in this paper is usually smaller because the additional virtual loadings needed are relatively fewer. It is of practical significance to various optimization methods in which the calculation of gradients of behaviours is widely used. Moreover, applying the derived formulas to the fully stressed design (FSD), we obtain an improved iterative method for FSD. The numerical examples show that the new method considerably reduces the reanalysis number required to converge to an FSD in comparison With the simple stress ratio method.     

溶剂交换法制备一维有机纳米材料

利用溶剂交换法制备了几种有机小分子化合物的一维纳米材料,并分别用SEM、TEM、XRD等对其结构进行了表征.分析了纳米材料的生长过程,讨论了有关的机理,并研究了其吸收光谱和荧光光谱等光物理行为.结果显示,有机纳米结构的形貌和尺寸对分子聚集体的光谱性质具有调制作用,使得它们展示出不同于溶液和体材料的优良纳米特性.