用于焊缝跟踪的调制式红外光学传感器

叙述了一种以脉冲调制的红外光束为信号光源的焊缝跟踪传感器。通过对接 收信号的滤波及“自适应消噪”处理,可以有效地克服电弧光的干扰;利用光源的脉冲 驱动特性,加大了瞬时信号功率,改善了光学传感器对工件表面的适应性。传感器结构简 单、体积小、灵敏度高、能同时实现对焊缝在水平及高度两个方向的自动跟踪在埋弧 及明弧自动焊中均能准确地跟踪。     

无源传感器引导AESA雷达目标搜索

无源传感器引导有源电扫阵列(AESA)雷达完成目标搜索是机载多传感器协同探测的重要应用形式。综合了引导传感器的测角误差以及目标运动产生的偏差2种因素,建立目标指示成功概率模型。提出了一种满足时效性、指示成功率和误交接概率要求的最优搜索策略。采用分步优化的方法在多种场景下对搜索策略和性能指标进行了计算。仿真结果表明:提出的搜索策略与传统搜索策略相比在满足指示成功率要求的前提下,通过增加较少的搜索波位,较大幅度地降低了误交接概率,保证了引导条件下目标搜索的准确性。     

无线多媒体传感器网络自适应拥塞控制算法

针对无线多媒体传感器网络(WMSN)中多对一通信时产生的网络拥塞问题,提出了一种自适应的WSMN网络拥塞控制算法ACCP。通过结合速率控制和资源调度,并采用分簇的网络结构,根据簇首及簇内的拥塞指标,来分别启动对应的拥塞控制机制:当簇首发生短时间拥塞时,就启动属于资源调度的网络内存储管理机制,来暂时减缓网络内过多数据包;但当簇中的存储节点也无法容纳过量的数据包时,速率控制就启动,让流量减缓下来,并且只调整数据实时性要求较低的数据流的速率,以达到控制流量、减缓甚至消除网络拥塞的目的。仿真结果显示:ACCP在传送速率不同下,可以比InS、HCCP更有效的控制网络拥塞的情况,而在比较缓存容量不同的情况下,虽然ACCP只比HCCP能够稍微改善网络拥塞的情况,但却能够大幅度改善InS的数据包丢失率。     

负载扰动观测器在SF型矢量控制系统中的应用

文章提出广义逆矩阵来设计离散型状态观测器的方法,用该法设计的观测器,可对SF型矢量控制系统的负载力矩进行估计,再进行前馈补偿。实验证明,该法可有效改善系统的动态性能。     

一种改进的树形矢量量化编码算法

矢量量化中的一个最严重的问题是在一本码本中搜索最近码字的高计算复杂度。本文在研究树形矢量量化的基础上提出了一种改进的树形矢量量化编码算法。实验结果表明,本文提出的编码算法相对于树形矢量量化算法可大大改善峰值信噪比（ＰＳＮＲ）。     

稳定非线性动力系统周期的计算机分析

提出采用后继函数法来确定非线性动力系统的周期,并编制计算机程序对Ｖａｎ ｄｅｒ Ｐｏｌ方程实例计算周期和绘制相图,结果表明,该方法计算结果准确且实用性强,本方法不但适合于求解保守系统和具 周期解非线性动力系统的周期,也适合于耗散系统和不稳定系统的分析。     

烯烃的分子距离边数矢量(μ)及沸点的估计与预测

基于双键相对于单键键长的大小,提出了烯烃的分子距离边数（ＭＤＥ）矢量（μ矢量）;进而通过多元线性回归方法建立μ矢量与烯烃沸点之间的关系模型并进行预测,计算沸点与实验值之间的均方根误差仅为３．７８Ｋ,相关系数为０．９９９３。     

信号流图的扩展及其应用

将信号流图扩展到状态空间构成所谓向量流图,用公式可实现组合系统规范化;按工答过程绘制信号流图构成所谓过程流图,可对系统组件作深入的分析。     

Cloning, construction of prokaryotic expression vector and expression ofEscherichia coli cytosine deaminase gene

Cytosine deaminase gene ofEscherichia coli strain H-30 was cloned, and its initiation codon of ‘GTG’ was mutated to ‘ATG’ by PCR. Prokaryotic recombinant expression vector pBV220-CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5-FC(5-FC, 5-fluorocytosine) could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H-30-CD-11 with high enzyme activity with CD gene reported in Gene Bank.     

Research advances in gene therapy for Parkinson's disease

During the long period of time when people have been seeking for an effective therapeutic method for PD, the gene therapy has shown greater and greater advantages over other methods. It can be performed mainly in two ways: ex vivo and in vivo. With the former, TH gene as well as some neurotrophic factor genes (such as GDNF, BNDF genes) can be invited to some cell lines or primary cells thus forming engineered cells and then implanting them into brain. While with the latter, viral vectors including HSV-1, Ad, AAV that can be utilized to construct recombinant viruses, or non-virus vectors can be used to delived DNA into brain directly. The present review summarizes the recent research advances in the gene therapy for PD, and it is reasonable for us to predict a notable progress in prevention and treatment for PD in the next decade.