超声波频率与功率对三合二洗消液抗冻性能影响的研究

针对严寒条件下三合二洗消液防冻结问题,研究采用向消毒液中释放大功率超声波的方法,较好地解决了三合二消毒液在低温时出现沉淀、冻结的问题．     

两种改进的m-最优多假设跟踪(MHT)算法

针对多假设跟踪(MHT)算法在跟踪多目标时出现的关联矩阵随目标及量测数急剧增长的情况,从降低聚矩阵行、列向量维数角度,提出了两种改进的m-最优MHT关联算法.仿真结果表明,所提出的改进方法不仅大大减少了由高维聚矩阵拆分所引起的庞大计算量,而且实现了对多个目标的有效量测-航迹关联,具有一定的实用性.     

Fabrication and analysis of TIG welding-brazing butt joints of in-situ TiB2/7050 composite and TA2

Lightweight hybrid structures of Al MMCs and titanium alloy dissimilar materials have great prospect in the defence industry application. So, it is necessary to join Al MMCs with Ti metal to achieve this structural design. In this work, in-situ TiB2/7050 composite and TA2 were firstly attempted to join by TIG welding-brazing technique. The result was that the intact welding-brazing butt joint was successfully fabricated. The joint presents dual characteristics, being a brazing on TA2 side and a welding on TiB2/7050 side. At brazing joint side, ER4043 filler metal effectively wets on TA2 under TIG heating condition, and a continuous interfacial reaction layer with 1—3μm is formed at welded metal/TA2 interface. The whole interfacial reaction layers are composed of Ti(AlSi)3 intermetallic compounds (IMCs), but their morphologies at the different regions present obvious distinguishes. The microhardness of the reaction layers is as much as 141—190 HV. At welding joints side, the fusion zone appears the equixaed crystal structure, and the grain sizes are much smaller than those of welded metal, which is attributed to the effect of TiB2 particulates from the melted TiB2/7050 on acceleration formation and inhibiting growth for the new crystal nucleus. The tensile test results show that average tensile strength of the optimal welding-brazing joint is able to achieve 138 MPa. The failure of the tensile joint occurs by quasi-cleavage pattern, and the cracks initiate from the IMCs layer at the groove surface of TA2 and propagate into the welded metal.     

Adaptive subspace detection based on two-step dimension reduction in the underwater waveguide

In the underwater waveguide, the conventional adaptive subspace detector (ASD), derived by using the generalized likelihood ratio test (GLRT) theory, suffers from a significant degradation in detection per-formance when the samplings of training data are deficient. This paper proposes a dimension-reduced approach to alleviate this problem. The dimension reduction includes two steps: firstly, the full array is divided into several subarrays; secondly, the test data and the training data at each subarray are transformed into the modal domain from the hydrophone domain. Then the modal-domain test data and training data at each subarray are processed to formulate the subarray statistic by using the GLRT theory. The final test statistic of the dimension-reduced ASD (DR-ASD) is obtained by summing all the subarray statistics. After the dimension reduction, the unknown parameters can be estimated more accurately so the DR-ASD achieves a better detection performance than the ASD. In order to achieve the optimal detection performance, the processing gain of the DR-ASD is deduced to choose a proper number of subarrays. Simulation experiments verify the improved detection performance of the DR-ASD compared with the ASD.     

德文版液压系统模拟仿真软件的汉化方法

介绍了德文版的 Fluid SIM-H液压系统模拟仿真软件 ,并介绍了应用 Exe Scope、Help Deco、Help Work和 Create Install等工具软件对德文版软件进行汉化的基本方法     

基于热物理仿真分析的红外点目标特征提取与识别

根据弹道中段空间目标和诱饵的表面温度分布规律，从热物理的角度分析了目标和诱饵的红外光谱辐射特性，指出了弹道中段目标和诱饵红外辐射特性的本质差别，并据此提出了红外目标识别中的特征基函数，用特征基函数构造红外点目标识别的四维特征矢量。仿真实验表明，这一特征矢量用于红外点目标识别非常成功。     

双基地两坐标雷达空间目标定位算法

本文提出了双基地雷达单独使用发射／接收站（Ｔ／Ｒ站）的目标斜距和方位角信息或接收站（Ｒ站）的目标距离和方位角信息分别对空中目标的二维定位算法，并给出了定位精度的分析方法。最后，通过计算机仿真讨论了算法的定位性能。     

TDOA被动定位方法及精度分析

本文提出了一种利用多站ＴＤＯＡ信息对辐射源定位的非线性方程组求解方法，该方法简洁准确，无需作迭代运算，计算量小。文中给出了该定位方法的精度分析，最后给出了在具体布站条件下的受控区域内的ＧＤＯＰ分布。     

利用Hough变换实现目标检测与航迹启动

经典的目标检测方法是Ｂａｙｅｓ方法，通常为门限检测。本文将利用Ｈｏｕｇｈ变换推导一种通过非相参积累实现目标检测和航迹启动的方法。针对目标的信噪比不同的情况，讨论了两种非相参积累形式，一种是直接积累，另一种是二值积累。二值积累在检测微弱目标时有独特的优越性。本文还讨论了两种非相参积累方法的理论检测性能。     

基于小波变换和数据融合的多导联ECG信号QRS波群精确检测算法

本文首先对单导联心电图（ Ｅ Ｃ Ｇ）信号的小波变换进行假设检验，得到 Ｑ Ｒ Ｓ波群的位置和检验的虚警漏报概率，然后对 １２ 导联检测结果作峰点比对融合和决策加权融合处理，最终得到精确的 Ｑ Ｒ Ｓ位置。实验表明这种方法对各种主要病症的 Ｑ Ｒ Ｓ波群均能准确检出，正确率在 ９９９５％ 以上。