基于惯性网络的分布式信息融合算法

分布式导航系统是飞机多传感器导航系统设计的新概念,可以大幅提高系统导航性能和容错水平,并能动态配置传感器功能,但是目前并无完善的信息融合算法与之对应;文章在构建惯性传感器网络的基础上,将多个低成本惯性传感器系统配置在飞机的多个位置以作为网络节点,设计了分阶段处理的分布式信息融合算法,综合利用各节点所测量的惯性信息,最后得到本节点的局部状态估计;通过仿真实验表明,采用此方法,有效降低了导航滤波估计误差,因此,系统导航性能及容错能力得到大幅提高。     

薄膜法X射线荧光光谱对重金属铬元素检测研究

研究了重金属Cr元素薄膜法X射线荧光(XRF)光谱分析中的滤膜,结果表明亲水性聚四氟乙烯滤膜对Cr元素富集具有较好的均匀性,并且对该滤膜上Cr元素进行XRF光谱测量具有较好的灵敏度。利用亲水性聚四氟乙烯滤膜对不同浓度的Cr元素进行富集,并且利用XRF光谱进行测试,结果表明当Cr元素的面积浓度在3.84~167μg·cm-2范围内时,Cr元素XRF光谱中Kα特征谱线的积分荧光强度与Cr元素的面积浓度之间具有非常好的线性关系,线性相关系数为0.996,检测限为0.3μg·cm-2。对实验室水龙头出来的自来水水样进行加标回收实验,得到回收率在93.85%~101.95%之间,相对标准偏差小于2%。因此,以亲水性聚四氟乙烯滤膜为富集滤膜的薄膜法XRF光谱分析法,能够很好地应用于水样中重金属Cr元素的分析与检测。     

基于色素特征荧光光谱的浮游植物分类测量方法

光合作用色素组成是浮游植物分类的重要依据。通过对蓝藻、绿藻、硅藻、甲藻和隐藻等5个门类浮游植物三维荧光光谱的差异性分析,提取了与叶绿素a、叶绿素b、叶绿素c、类胡萝卜素、藻蓝蛋白和藻红蛋白等光合色素相关的36个特征荧光光谱点,提出了基于色素特征荧光光谱的不同门类浮游植物分类测量方法。对铜绿微囊藻、小球藻、桅杆藻、光甲藻和卵形隐藻的实验结果表明:色素特征荧光光谱法对5种藻类纯种样品的测量误差分别为5.15%、5.63%、7.90%、4.85%、6.55%,对优势藻类(质量分数高于50%)的测量误差分别为7.96%、8.69%、5.44%、10.78%、15.57%,对劣势藻类(质量分数低于30%)的测量误差分别为18.29%、17.52%、20.01%、29.11%、20.14%,测量结果准确度达到了三维荧光光谱法水平,但数据量和计算时间仅是三维荧光光谱法的1.1%和2.2%,是一种快速有效的浮游植物分类测量方法。     

4通道交叉型二氧化硅光波导延迟线阵列的设计与制备

设计并制备了一种高集成度、低成本、低损耗4通道交叉型二氧化硅光波导延迟线阵列。利用BPM软件对交叉结构光波导延迟线的Y分支的损耗、弯曲损耗进行数值模拟。综合考虑器件尺寸和损耗参数,设计交叉型延迟线结构的弯曲半径最小为1 500 μm,引入优化的锥口Y分支结构和垂直相交波导结构。采用标准半导体制作工艺制备器件,测试得到了器件的红外输出光斑,延迟线延迟时间分别为0、113、226和339 ps。4通道二氧化硅延迟线阵列能实现相邻通道相等的延迟时间间隔,且可通过集成实现延迟时间的增加,同时输出端可以与光纤阵列集成。     

氢化物发生-原子荧光光谱法测定7种中草药中不同形态的水溶性砷

微波提取样品后,使用树脂分离不同形态的砷,以盐酸为测定介质,硫脲-抗坏血酸为预还原剂,硼氢化钾为还原剂,用氢化物发生-原子荧光法测定7种驱虫类中草药中的不同形态砷含量。砷含量在10—100ng/mL浓度范围内线性关系好,回收率在91.4%—106.4%之间。本方法简便、快速、灵敏、准确,可用于中草药中砷的形态测定。     

Curvelet-based palm vein biometric recognition

<正>A novel personal recognition system utilizing palm vein patterns and a novel technique to analyze these vein patterns is presented.The technique utilizes the curvelet transform to extract features from vein patterns to facilitate recognition.This technique provides optimally sparse representations of objects along the edges.Principal component analysis(PCA) is applied on curvelet-decomposed images for dimensionality reduction.A simple distance-based classifier,such as the nearest-neighbor(NN) classifier,is employed. The experiments are performed using our palm vein database.Experimental results show that the algorithm reaches a recognition accuracy of 99.6%on the database of 500 distinct subjects.     

Faraday-rotation self-interference method for electron beam duration measurement in the laser wakefield accelerator

Real-time single-shot measurement of the femtosecond electron beam duration in laser wakefield accelerators is discussed for both experimental design and theoretical analysis that combines polarimetry and interferometry.The probe pulse polarization is rotated by the azimuthal magnetic field of the electron beam and then introduced into a Michelson-type interferometer for self-interference. The electron beam duration is obtained from the region size of the interference fringes, which is independent of the pulse width of the probe laser. Using a larger magnification system or incident angle, the measurement resolution can be less than 1 fs.     

聚合物前驱体法制备WO_3薄膜的电致变色性能

以偏钨酸铵为钨源,Pluronic F127为配位聚合物,在FTO导电玻璃上制备了WO3薄膜,研究了配位聚合物含量对WO3薄膜电致变色性能的影响。实验结果表明,制备的WO3薄膜属于立方晶相;随着Pluronic F127含量的增大,WO3薄膜表面粗糙度增大,电荷容量先增大后减小;当Pluronic F127的含量为26%时,WO3薄膜的电荷容量最大,电致变色性能最好,可见光区域的透光率光学调制范围达到62.68%,光学密度差达到0.864,且着色态的太阳能总透射率低于褪色态的,制备的薄膜具有较好的节能效果。     

Dust-Induced Regulation of Thermal Radiation in Water Droplets

Accurate and fast prediction of thermal radiation properties of materials is crucial for their potential applications.However, some models assume that the media are made up of pure water droplets, which do not account for the increasing deviations caused by volcanic eruptions, pollution, and human activities that exacerbate dust production. The distinct radiation properties of water and dust particles make it challenging to determine the thermal radiation properties of water droplets containing ...