微波消解-石墨炉原子吸收光谱法测定鱼肉和河蚌中的重金属

建立微波消解样品,石墨炉原子吸收光谱法测定鱼肉和河蚌中重金属Pb,Cd,Cr,Cu,Ni含量的方法。优化了石墨炉原子吸收光谱法测定条件,在最佳实验条件下,选用磷酸二氢铵作为Pb,Cd,Cr,Cu的基体改进剂,抗坏血酸作为Ni的基体改进剂。Pb,Cd,Cr,Cu,Ni的检出限分别为0.05,0.01,0.05,0.05,0.07μg/g,实际样品测定结果的相对标准偏差为6.3%~14.5%(n=6),加标回收率为84.5%~113.0%。测定了牡蛎标准参考样,测定值在标准值可接受范围内。该方法检出限低、准确度高,适用于鱼类、河蚌样品中重金属含量的分析。     

Effect of the integrated time of the induced current signal on the position resolution of the RPC detector

A prototype RPC with position resolution less than 1 mm has been produced and studied. Based on this RPC detector, the effect of the width of the integrated FADC time window on the position resolution of a RPC has been studied experimentally and theoretically. The results of theoretical calculation and experimental measurement have shown good agreement.     

一种改进的时变转移概率AIMM跟踪算法

针对矢量线阵跟踪目标低频线谱提取问题,提出了一种矢量线阵低频线谱提取方法,其中利用拉平后线谱的均方差乘一比例因子设为门限的方法,可以有效提取线谱成分;并且研究了利用互谱中高信噪比线谱测向剔除干扰线谱方法,准确提取出目标特征线谱,可较有效解决矢量线阵左右舷目标低频线谱特征相互干扰问题。上述矢量线阵低频线谱提取方法,得到了海试数据的初步验证。     

Measurement of avalanche size and position resolution of RPCs with different surface resistivities of the high voltage provider

The effects of surface resistivity of the high voltage provider on the space dispersion of the induced charge of a prototype Resistive Plate Chamber （RPC） have been studied experimentally and theoretically. The results of both experiment and theory agree and confirm that a two-Gaussian function can be used to fit the dispersion of the induced charge of the RPC. It is shown that the Gaussian function with the narrower width is mainly due to the expansion of the avalanche charge in the gas gap of the RPC, and the Gaussian function with the larger width is due to the charge dispersion when it passes through the resistive carbon film. This will be useful in the RPC design when one wants to make an RPC with high position resolution.