Single Ultrashort Attosecond Pulse Generation via Combination of Chirped Fundamental Laser and an Ultraviolet Controlling Pulse

We theoretically study the high-order harmonic generation (HHG) from a hydrogen atom in an intense few-cycle chirped fundamental laser in combination with an ultraviolet (uv) controlling pulse.The high-order harmonic spectrum is calculated by solving the time-dependent Schr¨odinger equation using the split-operator method.In our calculation,we present the difference of the high-order harmonic spectrum from one-dimensional (1D) model hydrogen atom and three-dimensional (3D) real hydrogen atom.We found that the plateau of the high-order harmonic generation from the 1D case and 3D case are all extended effectively to I p + 35U p due to the presence of the chirped laser pulse and the HHG supercontinuum spectrum is generated by adding an ultraviolet controlling pulse at a proper time,but the efficiency of the HHG for 3D case is more higher at the near cut-off region than the 1D case.Therefore,the generation of the attosecond pulse by synthesizing the harmonics near cut-off region have some slight differences between 1D and 3D simulations.As a real 3D case study,we show that an isolated 18 as pulse with a bandwidth of 232.5 eV is generated directly by optmizing the combination laser fields.     

Two-colour coherent control of multiphoton ionization： a comparison between long-range and short-range potential model atoms

Using the numerical solution of the time-dependent Schr\"odinger equation of a one-dimensional model atom in a two-colour laser field, we have investigated the effects of the potential models on coherent control of atomic multiphoton ionization. It is found that the photoelectron spectra are obviously different for the long-range (Coulomb-like) and short-range (with no excited bound states) potential model atoms, which are produced by two-colour coherent control of atomic multiphoton ionization in a few laser cycles. Our results indicate that two-colour coherent control of atomic multiphoton ionization can be observed in simulations, depending on the choice of the model potentials.     

不同分子量壳聚糖和壳聚糖硫酸酯的抗氧化活性

不同分子量壳聚糖和壳聚糖硫酸酯的抗氧化活性;壳聚糖;壳聚糖硫酸酯;超氧阴离子自由基（ ）;羟自由基（·OH）;抗氧化活性     

弹体正侵彻混凝土靶动态开坑作用过程

为了进一步研究弹体侵彻混凝土靶的开坑作用过程，基于开坑破坏过程分析对开坑阶段进行划分，结合弹体头部形状函数、Z模型流线场分布以及法向膨胀理论，建立考虑混凝土飞溅过程影响的开坑阻力计算模型，并运用文献中试验数据验证模型的可靠性。在此基础上，进一步分析了典型弹靶参数对弹体侵彻混凝土靶动态开坑作用过程的影响规律。研究结果表明：弹体开坑飞溅区范围随弹体头部形状系数和混凝土强度的增大而减小；飞溅区范围达到稳定的时间和动态开坑作用时间随初速和混凝土强度的增大而缩短，随弹体头部形状系数的增大而增大；相较于弹体头部形状系数和混凝土强度，初始撞击速度对动态开坑作用过程的影响更显著。