Interaction of intense laser pulses with hydrogen atomic clusters

The interaction between intense femtosecond laser pulses and hydrogen atomic clusters is studied by a simplified Coulomb explosion model. The dependences of average proton kinetic energy on cluster size, pulse duration, laser intensity and wavelength are studied respectively. The calculated results indicate that the irradiation of a femtosecond laser of longer wavelength on hydrogen atomic clusters may be a simple, economical way to produce highly kinetic hydrogen ions. The phenomenon suggests that the irradiation of femtosecond laser of longer wavelength on deuterium atomic clusters may be easier than that of shorter wavelength to drive nuclear fusion reactions. The product of the laser intensity and the squared laser wavelength needed to make proton energy saturated as a function of the squared cluster radius is also investigated. The proton energy distribution calculated is also shown and compared with the experimental data. Our results are in agreement with the experimental results fairly well.     

离子通道噪声对神经元新陈代谢能量的影响

利用随机Hodgkin-Huxley模型对发生在不同膜面积、不同温度下的神经元新陈代谢能量损耗进行了数值模拟研究.与实际神经元进行比较,表明神经元细胞膜存在一个最佳的膜面积和最佳的温度. 在最佳的膜面积和温度下,神经元的新陈代谢能量损耗最小. 最佳的膜面积与实际神经元膜面积一致,并且这个最佳的温度与室温一致. 关键词： 噪声 离子通道 神经元 Hodgkin-Huxley模型     

Supercontinuous high harmonic generation from asymmetric molecules in the presence of a terahertz field

We have investigated high-order harmonic generation from asymmetric molecules. It is found that supercontinuous high harmonics,which are produced from asymmetric molecules by significantly steering the ionization,are broken down when the electric field of the 5-fs driving laser pulse is increased to 0.16 a.u. The high harmonic generation from asymmetric molecules with the presence of a terahertz field is also investigated. This reveals that the terahertz controlled laser pulse significantly increases the energy difference between photons,emitted from the ejected electrons,in the first and second halves of the optical cycle at the centre of the driving laser pulse. In this way,a 200-eV broadband supercontinuum can be produced in the plateau,from which a 60-as pulse with a bandwidth of 60 eV can be directly obtained with a minor post-pulse.