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HeH^(2+)分子多通道谐波发射的理论研究 被引量:1
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作者 刘航 刘辉 +1 位作者 孟凡顺 冯立强 《原子与分子物理学报》 北大核心 2017年第4期696-703,共8页
利用非波恩奥本海默近似模型,理论研究了强激光场下HeH^(2+)分子发射高次谐波的特点.计算结果表明,HeH^(2+)分子的谐波截止能量要大于经典预言值.理论分析表明,延伸的谐波截止能量是由于激发态激光诱导电子跃迁所产生的多通道电子电离-... 利用非波恩奥本海默近似模型,理论研究了强激光场下HeH^(2+)分子发射高次谐波的特点.计算结果表明,HeH^(2+)分子的谐波截止能量要大于经典预言值.理论分析表明,延伸的谐波截止能量是由于激发态激光诱导电子跃迁所产生的多通道电子电离-回碰过程所导致的.随后利用双色空间非均匀激光场机制,谐波截止能量进一步延伸,形成了1个由单一量子路径贡献而成的482 eV的超长平台区.该辐射能量相当于单色激光场场强被增强了3倍的结果 .并且高振动激发态会产生强度更高的谐波光谱.最后,通过适当的叠加谐波平台上的谐波,可获得一系列脉宽在30 as的超短X射线光源. 展开更多
关键词 多通道电离 HeH2+分子 高次谐波 阿秒X射线光源 空间非均匀激光场
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Independent Source Separation of Multichannel Electroencephalogram Based on Neural Network
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作者 YOU Rong-yi, HE Hong-sheng 《Chinese Journal of Biomedical Engineering(English Edition)》 2009年第3期102-106,共5页
A neural network method for independent source separation (ISS) of multichannel electroencephalogram (EEG) is proposed in this paper.Using the denoising function of wavelet multiscale decomposition,the high-frequency ... A neural network method for independent source separation (ISS) of multichannel electroencephalogram (EEG) is proposed in this paper.Using the denoising function of wavelet multiscale decomposition,the high-frequency noises are removed from the original (raw) EEGs.Then the multichannel EEGs are treated as the weighted mixtures and the expression of weight vector is obtained by seeking the local extrema of the fourth-order cumulants (i.e.kurtosis coefficients) of the mixtures.After these process steps,the weighted mixtures are used as the input of neural network,so the independent source of EEGs can be separated one by one.The experimental results show that our method is effective for ISS of multichannel EEGs. 展开更多
关键词 electroencephalogram (EEG) independent source separation ISS neural network wavelet decomposition
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