节能赛车车架的设计及其CAE分析优化

为优化节能竞技赛车的车架,利用PRO/E三维软件建模,并使用其自带的分析软件Mechanical对铝合金车架进行有限元分析,得到了车架危险截面和危险点,为优化阶段的新模型简化提供了依据。利用Workbench进行优化建模,分析了某节能车车架在典型工况下的刚度与强度水平,并在此基础上对车架进行了截面尺寸优化,使车架的局部变形与应力集中得到明显改善,车架质量从8.61 kg又化成7.15 kg,减重16.96%,实现了车架设计的轻量化。     

数列组的强仿射线性相关性

在线性空间中有向量组的线性相关和强仿射线性相关的概念.给出了数列组的强仿射线性相关和强仿射线性表示的定义,进而讨论了数列组的强仿射线性相关和强仿射线性表示的一些性质.     

激光质量测量的自适应衰减控制技术研究

针对激光光束质量测量的激光光强高精度控制问题, 提出一种自适应衰减调节激光光强度的方法。该方法基于单片机控制算法, 利用PC机反馈的光斑图像灰度差值计算得出激光光强需要衰减的倍数, 并通过衰减轮电机控制两组衰减片组合完成对激光光强度的自适应控制, 实现了成像系统闭环控制激光光斑强度, 从而快速、 准确地得到特定光强度的激光光斑图像。实验结果表明, 该方法与以往衰减控制相比,能准确地得到高精度灰度值激光光斑图像, 激光光束质量单次测量时间为5 s, 系统测量时间为3 min。     

以食品级原料进行植物乳杆菌发酵及其抗真菌活性的研究

用食品级的大豆蛋白培养基代替MRS培养基进行植物乳杆菌发酵,并对其抗真菌活性进行研究,以期获得安全性较高的食品防腐剂.实验结果表明,植物乳杆菌IMAU10014发酵大豆蛋白培养基后的上清液对娄地青霉具有较高的抑菌活性.为了进一步提高植物乳杆菌IMAU10014发酵液抗真菌活性,对不同碳源、氮源、pH和温度进行单因素研究,并通过L9(34)正交实验优化得到最佳培养基组合及培养条件:葡萄糖20,g/L、大豆蛋白5,g/L、pH 6.5、温度37,℃植物乳杆菌IMAU10014发酵48,h时抑菌效果最佳.对抑菌物质的理化性质分析结果表明:植物乳杆菌IMAU10014发酵浓缩上清液的抑菌活性对温度的变化不敏感;抑菌活性随着pH的升高而降低,经过蛋白酶K和胰蛋白酶处理后抑菌活性有所降低.     

Circular SAR processing using an improved omega-k type algorithm

An improved circular synthetic aperture radar (CSAR) imaging algorithm of omega-k (ω-k) type mainly for reconstructing an image on a cylindrical surface is proposed. In the typical CSAR ω-k algorithm, the rage trajectory is approximated by Taylor series expansion to the quadratic terms, which limits the valid synthetic aperture length and the angular reconstruction range severely. Based on the model of the CSAR echo signal, the proposed algorithm directly transforms the signal to the two-dimensional (2D) wavenumber domain, not using approximation processing to the range trajectory. Based on form of the signal spectrum in the wavenumber domain, the formula for the wavenumber domain interpolation of the ω-k algorithm is deduced, and the wavenumber spectrum of the reference point used for bulk compression is obtained from numerical method. The improved CSAR ω-k imaging algorithm increases the valid synthetic aperture length and the angular area greatly and hence improves the angular resolution of the cylindrical imaging. Additionally, the proposed algorithm can be repeated on different cylindrical surfaces to achieve three dimensional (3D) image reconstruction. The 3D spatial resolution of the CSAR system is discussed, and the simulation results validate the correctness of the analysis and the feasibility of the algorithm.     

RFID制造业仿真部署平台设计关键技术

为解决实际制造企业生产线上部署射频识别(RFID)设备成本高、周期长、尤其是效果不理想的问题,以测试数据为基础并利用面向对象的设计思想,设计和实现了一个界面友好的交互式RFID设备仿真部署平台。通过静态结构和动态结构的分析,该仿真平台实现了环境仿真、生产线仿真、读取标签仿真、消息传递、系统优化评估等关键技术,并已在某冰柜生产线得到成功应用。     

Quantized dynamic output feedback control for networked control systems

The problem of the quantized dynamic output feedback controller design for networked control systems is mainly discussed. By using the quantized information of the system measurement output and the control input, a novel networked control system model is described. This model includes many networkinduced features, such as multi-rate sampled-data, quantized signal, time-varying delay and packet dropout. By constructing suitable Lyapunov-Krasovskii functional, a less conservative stabilization criterion is established in terms of linear matrix inequalities. The quantized control strategy involves the updating values of the quantizer parameters μi(i = 1, 2)(μi take on countable sets of values which dependent on the information of the system measurement outputs and the control inputs). Furthermore, a numerical example is given to illustrate the effectiveness of the proposed method.     

一个本科生化学综合设计实验——双偶极Ru(Ⅱ)配合物和普鲁士蓝自组装多层膜的研究

用一种双偶极Ru(Ⅱ)配合物和普鲁士蓝分别代替一个本科生化学综合设计实验中的半菁和杂多阴离子,成功地制备了双偶极Ru(Ⅱ)配合物和普鲁士蓝的静电自组装多层膜,并通过紫外-可见光谱和电化学技术对薄膜进行了表征.结果表明:多层膜可被均匀沉积厚达至少12层,膜中普鲁士蓝与Ru(Ⅱ)配合物之间发生较强的电荷转移作用,具有良好的电化学活性.     

基于切换方法的控制器故障下多时滞系统稳定性分析

研究了控制器故障下具有非线性干扰的多时变时滞不确定系统的鲁棒指数稳定性问题.利用不确定多时变时滞切换系统模型描述了所考虑的系统.提出了基于平均驻留时间的切换方法.在此方法下,以线性矩阵不等式(LMIs)形式得到了切换系统鲁棒指数稳定的充分条件,并从理论上证明了即使控制器失效所生成的闭环系统也是鲁棒指数稳定的.最后通过仿真算例验证了所提方法的有效性.

Abstract：

The issue of robustly exponential stability for a class of uncertain multiple time-varying delay systems with controller failures and nonlinear perturbations is considered.A switched uncertain multi-delay system model is utilized to describe the considered systems.A switching approach based on the average dwell time is employed for the switched system.A delay-dependent sufficient condition for robustly exponential stability of the switched system is established in terms of linear matrix inequalities by using the switching method.It is proved theoretically that the resulting closed-loop system is robustly exponentially stable even if controller failures are encountered.The effectiveness of the proposed method is also demonstrated by simulation example.     

阴影衰落环境中移动Ad Hoc网络连通度分析及仿真

分别在理想传播环境和阴影衰落环境下,假设节点采用均匀分布,采用网络覆盖的方法对移动Ad hoc网络的连通度进行了理论计算,得出了在一定覆盖范围内,网络连通度、节点数与节点发射功率三者间关系的理论公式,建立OPNET网络仿真模型,并通过Matlab仿真验证其正确性.