Multiple collisions in crystal high-order harmonic generation

We theoretically investigate high-order harmonic generation (HHG) in crystals induced by linearly polarized laser fields. We obtain the HHG spectra by solving the semiconductor Bloch equations and analyze the radiation process by different models. Here we propose a multiple collision model, in which the electrons and holes are produced at different times and places. It is found that the multiple collision trajectories can help us comprehensively and better explain the results of the quantum calculation. Moreover, we find that the harmonic suppression occurs due to the overlap of multiple collision trajectories.     

地下储气库压缩空气温度时空分布与温控方法

为准确认识压气储能电站地下储气库在初次运行条件下的压缩空气动态热力学特性,建立了考虑压缩空气与围岩间共轭传热以及非等温流动的储气库热力学数值分析模型,并对其合理性进行了验证。通过对比分析等容积条件下不同洞室形状的储气库压缩空气热力学特性变化过程以及温度空间分布规律,提出了两种压缩空气的温控工艺并对其效果进行了分析。研究结果表明,不同洞室形状的储气库在相同工作压力下的压缩空气平均温度值差异较大;洞室形状对储气库压缩空气温度空间分布规律影响显著,其中隧道式储气库出现了局部高温现象;延长初次充气时间对隧道式储气库的温控效果较差,而合理布置进出气口位置对隧道式储气库的温控效果良好。