染料分析是研究织物颜色老化变色的基础, 同时对于了解我国印染工艺的发展有非常重要的作用. 通过薄层色谱和拉曼光谱方法, 对六个唐代丝绸样品的蓝色染料和故宫建福宫建筑彩画的蓝色物进行了分析, 并对两种方法在文物上的适用性进行了比较. 结果表明这些呈色物质均为靛蓝, 靛蓝不仅作为染料被古人使用, 也被当作颜料用于彩绘壁画, 使用范围非常广范. 两种分析的方法各有利弊, 拉曼光谱是无损分析, 薄层色谱需要样品量少, 但可获得更多的信息.

中国考古出土的丝织品数量大,种类丰富,是中国古代文化遗产的重要组成部分,但由于丝蛋白易于降解老化的材料特性,有许多保护问题需要研究解决。 对古代丝织品老化程度、老化特征的分析检测有助于了解丝织品的保存状况,并可为保护方法的选择与改进提供帮助。 文章通过X射线衍射分析对丝织品老化特征及结晶度的变化进行了研究。 样品为经光老化、热老化和水解老化的白色丝织品和出土于湖北、陕西、内蒙古、青海的古代丝织品。 X射线衍射分析结果表明,X射线衍射分析可以揭示丝织品的老化作用过程和老化特征, 以及相应结晶度的变化,对于出土古代丝织品保存状况及老化机理的研究来说具有实用价值。 同时还可为了解古代染织工艺的发展提供信息。

高能量密度物理(HEDP)是研究能量密度超过1011 J/m3的极端条件下物质结构与特性及变化规律的科学,开展此方面的研究对惯性约束聚变、材料物理、天体物理、加速器物理、**等具有极其重要的意义。主要介绍了我们在利用飞秒相对论性超强激光进行高能量密度物理研究方面所取得的一些进展,包括电子加速、离子加速(包括质子和重离子)以及其他一些有意义的结果。

Electron acceleration by a propagating short ultra-intense laser pulse in a low-density plasma has been investigated. Electrons have the maximum energy when meeting the peak of the laser pulse. If a propagating laser pulse is abruptly stopped by a solid target, the highly energetic electrons will continue to move forward inertially and escape from the laser field. The envelope of the laser pulse is taken into account and there is an optimal position between the electron and the solid target. The electron maximum energy depends on the laser intensity and initial electron energy, and has nothing to do with the polarization of the pulse, but a linearly polarized laser pulse is more effective to accelerate electron than circularly polarized one under the same laser energy. The influence of the reflected light has been taken into account which makes our model more perfect and the results give good agreement with particle in cell simulations.

We present the study of the interaction of an intense circularly polarized pulse with a solid target with one-dimensional (1D) particle-in-cell (PIC) simulation. The evolvement of ion motion with time is explained by a purely kinetic description and by the theory of electrostatic shock in collisionless plasmas. Especially the formation of the stable profile with a "double-flat-top" in ion phase space is explained and validated visually. Assuming the initial state, we find that the ion distribution in the phase space agrees qualitatively with the PIC simulation results by using the particle-tracing approach.

Two-dimensional particle-in-cell simulations are taken to study the interaction of a relativistic, circularly polarized laser pulse with a preformed overdense plasma channel containing a slice of micron size. The laser pulse is confined in the channel, so it can keep higher intensity on a longer time scale inside the channel than the case without a channel. The electrons, both in the slice and from the channel, are pushed forward in the channel by the large light pressure of the laser pulse, followed by the ions accelerated by the electro static field generated by the charge separation. As a result, the acceleration of the slice is more efficient and has a better collimation than in the case without a preformed channel.

研究了整形激光脉冲对冰冻氘氚靶的压缩。通过数值分析,发现利用分步激光产生的系列激波压缩氘氚靶可以获得较高密度和较低温度的等离子体靶。初始激光强度的选取将影响到压缩后的等离子体密度,继而影响到产生中子的数量。通过调节初始激光强度可以使压缩后的氘氚靶温度处在反应率比较高的范围内,从而得到优化结果。当初始归一化激光振幅为0.5,最终为32时,压缩后的氘氚靶密度可达到18416倍的临界密度,温度达到16 keV,每焦耳入射激光能量可得到109个中子,这个中子产额比现有其他方法所得到的中子产额大4个数量级。