基于虚拟仪器技术的布里渊自动探测系统设计

将虚拟仪器技术与受激布里渊散射理论相结合,提出一种新型的布里渊散射自动探测系统.利用功能强大的Lab-VIEW作为软件设计平台,对各种仪器进行实时精确的控制.设计了各个系统单元的LabVIEW控制程序以及部分硬件电路,测量并分析在不同深度下,ICCD接受到的受激布里渊散射回波信号的变化情况,提出了一种新型的探测系统,并对探测系统给出了详细的理论分析.新型的受激布里渊探测系统能有效地解决实验中人为因素造成的误差,提高了探测的深度和探测精度.     

光纤中受激布里渊散射的应用及研究进展

简单介绍了光纤中受激布里渊散射的研究进展,阐述了受激布里渊散射在光纤传感器、光纤陀螺及相位共轭镜中应用的基本原理和研究现状以及光纤传感器、光纤陀螺和相位共轭镜目前的发展现状,评述了基于受激布里渊散射的传感器和相位共轭镜未来的发展前景。     

分布式光纤传感器温度与应变区分的研究

针对分布式光纤传感器系统中温度和应变同时存在的问题,给出了一种联合受激布里渊散射(SBS)和后向瑞利散射来解决此类交叉问题的方法.根据光纤中SBS,后向瑞利散射与施加在光纤上的温度和应变的相关特性,分析了温度和应变对SBS,瑞利散射的影响.数值求解出在泵浦光入射端接收到的SBS信号光功率和后向瑞利散射光功率.由应变补偿并解调SBS信号光功率获得温度信息,并分析了应变对温度精度和空间分辨率的影响.     

基于虚拟仪器的激光水中传输规律的研究

将虚拟仪器技术运用于激光在水中传输规律探索.测量了不同能量的光束,通过不同长度的水介质在窄线宽与宽线宽两种情况下的衰减系数,研究了受激布里渊散射对激光在水中衰减特性的影响.利用功能强大的LabVIEW软件对各种先进仪器进行综合控制.然后对采集到的水中传榆激光能量信号进行处理,不仅提出了一种实时检测水的衰减系数的新方法.并且对激光监测系统的设计提供必要的理论及应用基础.     

受激拉曼散射和单模激光系统之间光信号的同步转换

研究了受激拉曼散射和单模激光系统之间光信号的同步转换问题。介绍了受激拉曼散射和单模激光Lorenz系统的特性。进一步设计了耦合控制器,通过构造合适的Lyapunov函数,得到受激拉曼散射和单模激光系统之间光信号实现同步转换的条件。数值模拟验证了同步原理的有效性。     

基于PPP-80TDA分布式光纤温度传感技术的数值模拟

基于脉冲预泵浦布里渊光时域分析法的分布式光纤温度传感技术是近年来出现的一种新型温度传感技术.本文采用有限差分法对一维瞬态受激布里渊散射的耦合波方程进行了数值求解,分别模拟了传感器在不同温度情况下的布里渊散射三维频谱图,得到了布里渊散射谱的中心频率、布里渊频移以及功率随温度变化的趋势.仿真结果表明,理论模拟与实际相符,并...     

布里渊光时域分析传感器中光偏振控制技术的研究

普通单模光纤的布里渊光频移是光纤温度和应变的函数,可利用布里渊光时域分析(BOTDA)技术来测量光纤各点的温度、应变分布情况。但受激布里渊散射信号在光纤中存在偏振相关性问题,这会影响信号的精度和准确性。本文实验研究正交偏振控制和随机偏振控制技术抑制布里渊光时域分析系统的偏振相关性,优化BOTDA系统的检测性能。     

水下激光引信回波功率研究

针对目前水下激光引信无法选取其激光器合适的发射功率,对水下激光引信的回波功率展开研究。为计算应用于相关海域的水下激光引信所需的激光发射功率,通过推导水下激光引信探测目标的回波功率方程,计算海水各成分对532 nm绿激光的衰减系数,最终获得水下激光引信探测给定距离时所需的发射脉冲激光峰值功率计算公式。对所得公式在不同海水参量条件下进行仿真计算,仿真结果表明:对于应用于一般较清洁海域的水下激光引信,选择峰值功率不小于10 kW的脉冲激光器就能够探测到10 m处的目标,满足激光近炸引信的使用要求。所得的仿真计算结果可为水下激光引信应用于不同海域时激光发射功率的选择提供理论依据。     

小波阈值降噪提高ＢＯＴＤＲ测量精度研究

布里渊光时域反射仪（Brillouin Optical Time Domain Reflectometer, BOTDR）通过单端探测 光纤中的自发布里渊散射来实现布里渊频移测量,存在信噪比较低的缺陷。为此,本文采用小波阈 值降噪对微波外差扫频 BOTDR 测量过程中的每条单频功率曲线进行噪声抑制,最终提高 BOTDR 测量精度。简述了小波阈值降噪原理,构建了基于微波外差扫频测量的 BOTDR 仿真模型,通过仿 真分析不同小波变换参数对测量精度的影响,确定了最佳小波阈值降噪方案。搭建了微波外差扫频 BOTDR 光路及电路实验装置进行温度测量实验,在 10km 传感光纤上对降噪算法进行了实验验证。 实验结果表明,相比于降噪前,降噪后传感光纤末端变温区布里渊频移测量波动极差从 5.8 MHz 降 低至 3.2 MHz,均方根误差由 1.2 MHz 降低至 0.16 MHz,测温精度由±2.545℃提升至±1.4℃。理论仿真和实验研究证明,采用小波阈值 降噪可提升 BOTDR 测量精度。     

分布式传感技术在高强筋活性粉末混凝土裂缝监测中的应用研究

基于受激布里渊散射的光时域分析技术(BOTDA),本文采用分布式光纤传感技术监测高强筋活性粉末混凝土梁裂缝开展情况.首先进行了分布式光纤监测裂缝可行性试验研究,结果表明,分布式光纤监测具有识别并定位裂缝的能力且测试精度高.在此基础上,将分布式光纤布设在高强筋活性粉末混凝土梁的表面和内部监测裂缝发展情况,结果表明分布式光纤可监测混凝土梁裂缝开展的全过程,且分布式光纤监测的时空连续性可有效解决裂缝产生的时空随机性问题.     

气泡微细化实验中的光路设计及图像处理

气泡微细化实验是对工业中钢水脱硫的水力学模拟，根据相似性原理建立水模型实验，通过研究水模型实验中运动气泡的几何特性和运动特性来分析实际工业生产中脱硫剂的使用效率。通过设计合适的光路来获得最佳效果的拍摄图像；利用不同的图像处理流程分别对运动气泡图片进行处理，获得运动气泡的几何特性和运动特性。利用处理出来的数据进行气泡微细化实验分析，并对不同搅拌条件下气泡微细化实验的图像进行处理，寻找出最佳的气泡微细化实验条件。应用结果表明，所得出的最佳实验条件可大幅度提高镁的精炼反应效率，使反应速度加快，脱硫效率显著增长。     

Detecting marine intrusion into rivers using EO-1 ALI satellite imagery: Modaomen Waterway,Pearl River Estuary,China

Because of increasing marine intrusion into the Pearl River Estuary (PRE) in China, salinity has become one of the important and necessary hydrological and water quality monitoring parameters. In this research, we examined the relationships between the reflectance from Earth Observing-1 (EO-1) Advanced Land Imager (ALI) satellite imagery and total suspended solids (TSS) based on the synchronous in situ spectra analysis of the river water, in an attempt to detect salinity using remote sensing technique. The study site was the Modaomen Waterway in the PRE, Guangdong Province, China. We found a strong negative linear relationship between in situ reflectance at 549 nm and TSS concentrations (R ²?=?0.91, p < 0.001) when the salinity of the river was less than 1.46‰. It indicates that the TSS near Pinggang and Nanzhen in Modaomen Waterway of PRE tends to be dominated by organic mater carried by the particles and this is one major reason for the inverse relation between reflectance and TSS. Meanwhile, a strong correlation was observed between salinity and TSS (R ²?=?0.70, p < 0.001). The salinity-TSS model accounted for 70% of variation in salinity and allowed the estimation of salinity with a root mean square error (RMSE) of less than 0.036‰ when the TSS concentrations were between 7.4 and 28 mg l^?1. Therefore, we were able to develop a new method of detecting surface salinity of the river estuary from the calibrated EO-1 ALI reflectance data. The EO-1 ALI derived surface salinity and TSS concentrations were validated using in situ data that were collected on 18 December 2005, synchronous with EO-1 ALI satellite imagery acquisition. The results showed that the semi-empirical relationships are capable of deducing the TSS concentrations and then salinity from EO-1 ALI imagery in the PRE under low salinity. The methodology of detecting salinity from ALI imagery provides potential to monitor coastal saltwater intrusion and provides the water supply and conservancy authorities with useful spatial information to spatially understand and manage the marine intrusion.     

基于空间向量遗传聚类的海洋环境监测数据分析

给出了一种空间向量遗传聚类分析方法,对海洋环境监测得到的多参数数据进行分析。采用空间向量遗传聚类方法对采样点的温度,盐度,pH,DO等参数进行聚类,并将聚类结果投影到环境监测参数特征空间,便可以在特征空间中直观地对监测区某一时段采样点进行多参数数据分析,获知各采样点水质状况。通过对不同时段采样点数据的聚类分析,还可以对监测区海水变化趋势进行判断。此方法不仅能挖掘出采样点数据的关联性,而且使得对多采样点多参数数据的分析变得直观、清晰,提高了对海洋环境监测数据的分析效果。     

料流轨迹图像中特征半径的分析和提取

本文针对目前高炉布料轨迹测量分析的困难,引入模式识别技术,提出激光栅格物理标定方法,对料流轨迹图像的边缘算法进行对比分析,分析不同算法的图像处理结果,采用非固定探测的方法获得边缘算法的阈值。并根据不同激光波长的料流轨迹成像效果,对图像的特征半径的动态分析,对图像的不同特征点采用不同长度的特征半径分析,得到料流轨迹落点分布和料流宽度信息,重建料流轨迹极坐标分布图,为料流轨迹图像的信息获取提供更精确的数据,实现高炉操作的闭环控制自动化和工业信息化的精确要求。     

变化光照目标图像合成的球调和方法

光照是真实感绘制技术中的一个关键因素。研究了朗伯反射的球调和表示，提出了一种基于球调和函数的任意光照目标图像生成方法。该方法在给定目标基图像及其对应光照属性的基础上，通过基图像数据矩阵的奇异值分解（SVD）分离场景环境光分量、反演计算场景反射率和表面法向量等。新光照条件下绘制图像时，采用四阶球调和函数拟合入射光和朗伯反射核计算直接光照；间接光照采用分离出的基图像环境光分量拟合。实验表明：该方法能够保证绘制精确度，适合复杂光照条件下的目标图像生成。     

弓网电弧接触线温度分布仿真研究

为了分析弓网电弧对接触网导线温升的影响,以接触线为研究对象,建立了电弧作用下弓网系统滑动摩擦副的三维有限元模型,利用COMSOL Multiphysics仿真分析,得到不同类型的接触网导线在不同环境下的温度分布特征.结果表明:相同条件下,铜镁合金、纯铜、铜锡合金接触线的温升依次升高.接触线的截面积越大温升越高.同种接触导线分别处于正常、覆冰和潮湿状态时,接触线的温升依次升高.仿真结果对选择接触线以及降低弓网电弧对接触线的热损伤具有一定参考价值.     

The intensity of auditory warning tones in the automobile environment: detection and preference evaluations

A variety of auditory warning tones was evaluated to determine generally appropriate intensity levels for presentation in the automobile environment. Twenty-four subjects listened to tones presented at several intensity levels under three background noise conditions recorded in actual vehicles: relatively quiet (35 mile/h (56 km/h), smooth road), relatively loud (55 mile/h (89 km/h), rough road), and radio (35 mile/h (56 km/h), smooth road, and radio broadcast). Data were gathered on the minimum intensity level (in decibels (dB) above the masked threshold (MT) required to achieve a consistent criterion detection rate, as well as the preferred tone intensity level (in dB above the MT) in each background noise condition. The preferred levels were louder than those required to achieve the detection criterion in both the relatively loud and quiet background noise conditions; thus, the preferred levels are the recommended levels under those conditions. This was not the case in the radio condition; therefore, it is recommended that future research efforts evaluate the effects of automatically muting the radio/stereo system when important auditory warning tones are being presented.     

捷联惯组验前分布随机加权分散融合估计

在小子样理论中,验前分布的获取与表示是一个关键问题.获取验前分布必须利用各种验前信息,而这些信息是在不同实验条件下得到的,针对同一对象可能获取多种验前信息,如何合理地利用这些验前信息给出验前分布,这样就出现了多源验前信息融合的问题.针对捷联惯性测量组合(捷联惯组)历次测试数据验前分布的获取问题,讨论了在异总体情况下,多种验前信息的融合问题.提出了通过随机加权分散融合法来实现多种异源信息融合,获取捷联惯组历次测试数据验前分布,从而减小了小样本情况下的统计分析误差.通过实例检验取得了良好的效果.     

MRS-kNN fault detection method for multirate sampling process based variable grouping threshold

For the multirate sampling process, some traditional multivariate statistical process monitoring methods cannot perform well because the lengths of all samples are not consistent. To handle this problem, a multirate sampling k-nearest neighbor fault detection method is proposed in this paper. The training sample set is divided into different groups according to the length of the sample to ensure that the sample length of each group is uniform. For all the groups, we can get a variable threshold corresponding to samples of different lengths. Also, this model can be developed into one that is suitable for fault detection of various sampling rate processes. Finally, the effectiveness of the proposed method is demonstrated by the simulation experiments on a numerical example and an industrial process.     

SMAP Satellite Sea Surface Brightness Temperature Simulation and Sea Surface Salinity Retrieval

Sea surface salinity remote sensing is one of the important contents of the remote sensing research of the ocean. For the influence of the sea surface salinity remote sensing caused by the atmospheric, according to the theory of atmospheric radiation transfer, the atmospheric radiation effects were simulated and corrected, and then the sea surface salinity was inverted by the neural network model. The result showed that the atmospheric radiation effect was serious, and it needed to be corrected. When the precision of atmospheric temperature and pressure of the earth surface was 2 ℃ and 10 hPa, the atmospheric influence could be removed. The difference in the number of the training sample sets would have a certain impact on the accuracy of neural network inversion. The salinity retrieval relative error of the SMAP satellite was small, and the residual error was basically concentrated within 0.6, but the error was larger in the region where the salinity value is lower than 34.4‰.