高功率紫外超短激光脉冲光束质量研究

通过搭建传输和聚焦光学系统,采用CCD相机测量了高功率紫外超短脉冲激光系统的光束质量参数,如紫外种子光及其经过KrF准分子激光器放大后的焦斑光强空间分布、焦斑尺寸及极限衍射倍数β。结果表明,紫外种子光光束质量良好,β接近于1。经放大后,光束质量劣化,β达到6左右。经分析,光学元件的表面缺陷可能是导致光束质量下降的主要因素。     

提取干酪素分离过程排渣困难的原因分析

针对碟式离心机提取干酪素的分离过程中排渣困难的问题,分析了结垢积渣的原因,讨论了对产品质量、生产效率和设备的影响,从乳脂分离工艺及碟式离心机分离参数等角度考虑,提出了解决此问题的方法.     

Proton Acceleration Driven by High-Intensity Ultraviolet Laser Interaction with a Gold Foil

Proton acceleration induced by a high-intensity ultraviolet laser interaction with a thin foil target was studied on an ultra-short KrF laser amplifier called LLG50 in China Institute of Atomic Energy(CIAE).The ultraviolet laser produced pulses with a high-contrast of 109,duration of 500 fs and energy of 30 mJ.The p-polarized laser was focused on a 2.1 μm gold foil by an of-axis parabola mirror(OAP) at an incident angle of 45°.The laser intensity was 1.2×1017W/cm2.The divergence angle for proton energy of 265 keV or higher was 30°,which was recorded by a CR39 detector covered with 2 μm aluminum foil in the target normal direction.The maximum proton energy recorded by a CR39 detector covered with a 4 μm aluminum foil was 440 keV,and the proton energy spectrum was measured by a proton spectrometer.The ultraviolet laser acquires a relatively lower hot electron temperature,which can be ascribed to the proportional relationship of Iλ2,but a higher hot electron density because of the higher laser absorption and critical density.Higher electron density availed to strengthen the sheath electric field,and increased the proton acceleration.     

一种基于文本的领域本体进化需求自动生成模型①

本体进化研究已经成为领域本体研究的一个重要内容。本体进化需求是本体进化的前提,提出一种基于文本的本体进化需求自动生成框架,首先从自然语言描述的纯文本中提取相关概念,然后利用加权词频算法判断是否为领域关键概念,最后结合本体搜索算法和进化需求生成规则,自动生成本体进化需求。