Small moving infrared space target tracking algorithm based on probabilistic data association filter

Numerous false alarms for low signal-to-noise ratio (SNR) would seriously debase the performance for infrared low observable (LO) space target tracking. Due to the motion (i.e. azimuth, elevation and their derivative velocity), amplitude and size of infrared target are almost invariable and highly correlative, a multi-feature association approach based on probabilistic data association (PDA) is presented to track target in this paper. Firstly, the motion, amplitude and size of target are modeled as stationary random signal afforded Gaussian distribution. The probability of motion, amplitude and size of measurement originated as the target of interest is then estimated by Gaussian distribution, and that of false alarm is distributed uniformly. Subsequently, the combined probability of motion, amplitude and size is derived by PDA, and their weight coefficients are estimated adaptively according to their fluctuations. Finally, the relevant parameters including combination measurement are predicted and updated. Some experiments are included and the results show that the performance of target tracking by the proposed approach is significantly enhanced.     

Studies of the Polydiacetylene Bis-p-chlorocinnamate of 10,12-Docosadiyn-1,22-diol

The bis-p-chlorocinnamate of 10,12-docosadiyn-1,22-diol polymerized with ⁶⁰Co gamma radiation to give a soluble polydiacetylene (PDA), PDA-ClCIN-22. We have studied PDA-ClCIN-22 in both crystallographic powder and solution coated films. Thin films of solution coated PDA-ClCIN-22 exhibit an absorption maximum of 544 nm, similar to the concentrated solution in chlorobenzene. Irradiation of these films with 254 nm UV light in air leads to loss of intensity in the visible spectrum. The thin films of PDA-ClCIN-22 are amorphous by X-ray powder diffraction. Irradiation of both PDA-ClCIN-22 powder and film with 254 nm light did not result in photochemical reactivity of the chlorocinnamate group as recorded by FTIR spectra. Differential scanning calorimetry (DSC) studies of PDA-ClCIN-22 reveal that presence of monomer and endothermic transitions near 116°C and 134°C on a first heating. On a second heating of a sample of PDA-ClCIN-22 taken to 150°C on first heating, the 116°C and 134°C endotherms are absent. These endotherms are also lost by monomer extraction with boiling cyclohexane. One possible source of the endotherms would be conformational transitions in the side chain.     

Simultaneous determination of seven main alkaloids of Chelidonium majus L. by ultra‐performance LC with photodiode‐array detection

A simple and rapid method for the simultaneous determination of seven isoquinoline alkaloids, protopine, chelidonine, coptisine, stylopine, sanguinarine, berberine, and chelerythrine, in Chelidonium majus L. (Ch. majus) samples by ultra‐performance LC method with photodiode array detection is described. The baseline separation of these compounds was performed with (A) acetonitrile–(B) ammonium acetate (10 mM, adjusted to pH 3.0 with acetic acid) as the mobile phase using a C18 RP column (2.1×100 mm, 1.7 μm). Optimized conditions resulted in excellent peak shapes. The seven alkaloids were completely separated within 20 min. Good linear behaviors (r≥0.9992) over the investigated concentration ranges were observed for all the analytes. Validation proved the repeatability of the method was good and recovery was satisfactory. The validated method was successfully applied for 20 batches of Ch. majus. These results demonstrated that the ultra‐performance LC photodiode array method proposed was very useful in the analysis and quality control of Ch. majus.     

圆柱空腔内涡破裂的LDA三维流动测量

针对旋转圆柱空腔内旋转流场泡状涡破裂现象,设计了实验装置,分析了实验系统中光路设置、折射率补偿、示踪粒子选择等关键问题的处理方法,采用激光多谱勒速度测量技术ＬＤＡ（ＬａｓｅｒＤｏｐｐｌｅｒＡｎｅｍｏｍ ｅｔｒｙ）进行测量,给出了圆柱空腔内子午面上二维速度全场和涡破裂区域的内部三维流动测量结果． 同时给出的数值计算模拟结果和实验测量结果非常吻合．     

气固两相圆湍射流颗粒对气相流动的影响

采用PDA测量气固两相圆湍射流中轴线上的气相轴向平均速度及轴向和径向湍流强度,并与相同出口速度的单相射流进行比较。研究不同颗粒对气相的调制作用。喷口直径为20 mm,出口Re为13600。采用了从50μm到300 μm不同平均直径的六种密度为2500 kg/m3玻璃微珠作为颗粒相。各组实验质量气载比为0.5。结果表明不同粒径的颗粒对两相流场中气相的平均速度、轴向和径向湍流强度均有不同影响。150μm以下的颗粒对气相湍流有明显抑制作用, 200μm以上颗粒对气相湍流有加强作用。颗粒对气相湍流调制规律的分界取与颗粒随拟序结构扩散的分界不同。     

Identification of "insoluble" red dyewoods by high performance liquid chromatography-photodiode array detection (HPLC-PDA) fingerprinting

The paper describes a high performance liquid chromatography-UV/Vis spectrometry detection analytical approach to the identification of some redwood species of historical importance in textile dyeing. The group of extracted dyestuffs considered as "insoluble" because of their non-aqueous or alkaline extraction conditions is present in the wood of the Pterocarpus family and Baphia nitida species. First, the crude extracts of tinctorial and related species and their chromatographic fingerprints were studied. This part of work shows that some species not yet mentioned in the literature have potential dyeing properties. Subsequent experiments performed on the redwood cargo of a 200-year-old archaeological shipwreck allowed identification of the water-logged wood species. Furthermore, the different methods of dyestuff extraction used for dyeing according to traditional recipes and their impact on analytical results were studied. They show that standard recovery obtained by acid hydrolysis of dyestuff from dyed yarns is inadequate. Hence, alternative solvent-based procedures were proposed. The identification of species in textile threads then becomes possible. The applied approach was validated by analysis of dyed reference yarns with some indications of crude material extraction mode. The employed method of analysis seems to be useful for "insoluble" wood species identification in cultural heritage artifacts as well as for phytochemical purposes, despite the fact that very few detected color compounds were chemically identified.     

声频下驻波管中微粒的悬浮现象及其相位多普勒测量

本文在声频信号下发现驻波管底部的微小颗粒群在一定声场强度下会腾空而起，在管中形成稳定的悬浮层。通过相位多谱勒（PDA）测量发现，只有粒径在一定范围内的颗粒才能稳定悬浮在管中，且颗粒悬浮层中颗粒的粒径按一定的高度规律分布，这一结果在粉尘颗粒分离，分级中有广阔的应用前景。     

近红外光谱法测定PDA中残留丙烯酰胺含量

选取38份实验室自制二甲基二烯丙基氯化铵与丙烯酰胺的共聚物(PDA)为样品,用紫外光谱法对PDA中残留丙烯酰胺(AM)含量进行测定,并进行近红外光谱扫描,在图谱中选取七个波段,将每个波段的特征峰作为自变量,吸收峰作为因变量,采用偏最小二乘法(PLS)的数学转换方法建立近红外反射光谱(NIRS)定标模型,采用小波分析对光谱进行降噪处理,建立PDA中残留AM含量的近红外预测模型,并将预测值与紫外光谱法测定值进行比较,其外部验证决定系数达到0.99,预测分布趋势良好,对预测值与实测值进行t检验,结果显示预测值与实测值差异不显著。试验结果表明,采用近红外光谱数据建立的定标模型预测PDA中残留AM单体含量具有较高可行性。