This paper proposed a morphological component analysis (MCA) method, which is based on sparse representation, to detect the spike wave in electroencephalogram (EEG) signals. It takes the advantage of MCA being able to extract the background waves and the spike waves from the EEG signals, respectively,as the dictionaries and chooses the discrete cosine transform (DCT) and the daubechies order 4 wavelet (db4) transformation as the dictionaries of MCA to detect the spike waves from the epileptic EEG. The experiment results showed that the MCA could detect epileptic spike waves in EEG signals very effectively, and it yielded high selectivity of 89.01% and sensitivity of 90.71%. As a feature extraction/decomposition algorithm, MCA can be used to extract the spike waves from EEG signals.
Algorithms ; Electroencephalography ; methods ; Epilepsy ; classification ; diagnosis ; physiopathology ; Humans ; Principal Component Analysis ; methods ; Signal Processing, Computer-Assisted ; Wavelet Analysis

Objective:To overcome the disadvantages of bismuth removal by bismuth sulfide precipitation method recommended by existing analytical standards and improve the quality of analytical result.Methods:Based on 201×7 anion exchange resin, the experimental process of bismuth removal was designed, and verified by using spiked samples and IAEA test samples.Results:Bismuth was removed by anion exchange resin. In the removal experiments of strontium, yttrium and bismuth, the chemical recovery rate of strontium and yttrium could reach (98.6 ± 0.8)% and (98.5 ± 0.7)%, respectively, with no Bi 2S 3 precipitation found. The relative standard deviation between analytical result and theoretical values was -2.97% to 5.94%, better than 3.96%-17.8% by the standard bismuth removal method. Through validation using IAEA test samples, the relative standard deviation between the reported value and the target value for 90Sr was between 3.40%-7.09%, and all the results were acceptable. Conclusions:Bismuth could be quantitatively removed using anion exchange resin without adsorption of strontium and yttrium. In addition, the bismuth removal solution system of anion exchange resin was the same as the elution system in 90Sr analysis, and the purpose of rapid bismuth removal could be achieved without conversion system. Compared with the current standard analytical method, it was feasible and better to quantitatively remove bismuth based on anion exchange resin, which could meet the needs of routine analysis of 90Sr.

Transuranics radionuclides are ubiquitous in the environment. Long term intake will cause internal radiation hazards, and it is also an important source of radioactive contamination to the environment in the future. In this paper, the source and migration behavior of transuranic radionuclides are reviewed, the existing problems in China are summarized, and the suggestions for future work are put forward.