可区别铁离子荧光探针异构体的合成及其水样分析

分别以2-(2-氨基苯基)菲并咪唑和2-(3-氨基苯基)菲并咪唑为原料,与5-硝基水杨醛反应合成了两个菲并咪唑-苯酚异构体衍生物(PI-o-OH和PI-m-OH)。在水相体系中(V(DMF)∶V(HEPES)=1∶1,pH=7.4),两个异构体发射中等强度的荧光。Fe^(3+)存在下,两个异构体的荧光强度分别淬灭为原来的1/3和1/6,淬灭常数为4.8×10^(3)和4.6×10^(3)L/mol,且淬灭效果不受其它干扰离子和pH值变化的影响。间位异构体PI-m-OH与Fe^(3+)的荧光识别在2 min之内完成,配合速度明显优于邻位基异构体,且配合稳定性高于邻位异构体,配合常数为3.82×10^(3)L/mol。通过高分辨质谱和Job’s曲线,确定了两个异构体与Fe^(3+)识别配合比为1∶1,并建议了PI-m-OH-Fe^(3+)and PI-o-OH-Fe^(3+)两个配合物的结构。两个异构体均可实现实际水样中Fe^(3+)的定量检测,表明它们在实际水样的Fe^(3+)分析中具有一定的应用价值。

激活模式视野下的心理词典理论研究

本文对心理词典理论中激活模式进行了研究,并对激活模式的三个层次:区别特征识别层、音素识别层、词汇识别层,进行了分析。通过探讨它们不同的特点,揭示它们在此心理词典中的相互作用和相互关系,来揭示二语习得的学习规律,廓清学习过程中的障碍。

Efficient Approach for Face Detection in Video Surveillance

Security access control systems and automatic video surveillance systems are becoming increasingly important recently,and detecting human faces is one of the indispensable processes.In this paper,an approach is presented to detect faces in video surveillance.Firstly,both the skin-color and motion components are applied to extract skin-like regions.The skin-color segmentation algorithm is based on the BPNN (back-error-propagation neural network) and the motion component is obtained with frame difference algorithm.Secondly,the image is clustered into separated face candidates by using the region growing technique.Finally,the face candidates are further verified by the rule-based algorithm.Experiment results demonstrate that both the accuracy and processing speed are very promising and the approach can be applied for the practical use.