点火靶半腔套装实验系统设计

根据美国NIF点火基准靶REV4.0要求,对半腔套装工艺进行了具体的参数分析,确定了半黑腔与冷冻罩的铝套筒过盈配合公差带等关键参数,制定了装配系统技术指标,设计了系统方案,研制了实验样机。该样机具有12个电控台,重复定位精度达到0.3 m和0.01,并配备激光测头和6轴微力传感器,对靶件姿态与套装过程中的受力情况进行检测,可完成半黑腔套入与入射孔衬垫装配两道工序。利用该样机对模拟靶件进行了装配实验,半黑腔与铝套筒同轴度为8 m,轴向与径向夹角优于0.5,验证了装配工艺与系统功能的有效性。     

ICF点火靶定标关系与稳定性优化设计研究

激光等离子体相互作用（LPI）和瑞利-泰勒流体不稳定性（RTI）是影响间接驱动惯性约束聚变成功的两个主要不确定性因素。点火黑腔内环激光通道在靠近黑腔壁的区域是内环激光SRS背反产生与发展的主要区域。内环通道在该区域满足通道内外压力平衡和能量平衡条件。据此提出了间接驱动惯性约束聚变点火黑腔等离子体定标关系。结合描述靶丸内爆飞行阶段物理以及内爆性能的两个定标关系,提出了描述稳定性相对性能的指标。该指标可以指导点火靶设计,为LPI和RTI提供需要的裕量空间,是点火阈值因子（ITF）的补充。     

离子-电子非平衡机制降低中心热斑点火条件

提出通过离子-电子非平衡物理模型来降低惯性约束聚变中心热斑点火的聚变点火条件。在该物理模型中,强调离子比电子具备更高的温度,从而使得热斑的热核聚变反应增强,轫致辐射和电子热传导造成的能量漏失相对降低。通过对中心热斑的自加热分析和热斑燃烧动力学分析,发现相对于平衡聚变点火模型,非平衡模型可以显著扩大聚变点火区在热斑面密度和热斑温度空间的范围。同时采用LARED-S程序的数值模拟,研究了通过尖峰脉冲波形、二次冲击物理机制强化中心热斑聚变点火的非平衡性。     

点火位置对激光等离子体减阻效能的影响

利用激光等离子体减小高超声速飞行器波阻是一种新概念减阻方式,点火位置是研究减阻效能的重要参数。基于有限体积法和分区结构网格划分的高分辨力数值方法, 在气流马赫数为6.5、飞行高度为30 km条件下,计算了不同点火位置对减小高超声速飞行器波阻的影响。研究结果表明：利用激光等离子体可以有效地减小高超声速钝头体飞行器波阻;点火位置到驻点的距离与飞行器直径之比为2时,减阻效果最好,且数值模拟与理论计算结果吻合较好。     

爆推快点火模型分析

使用简单的爆推模型估算爆推快点火过程及其结果。 首先由ns级主驱动激光直接驱动,形成中心低密度高温热斑,周围为高密度低温主燃料区, 两区压力平衡(等压模型);然后用ps级超短超强激光打入,产生超热电子,其能量在低温主燃料区沉积,主燃料区发生爆炸,一部分向外飞散,一部分向内压缩中心热斑。在这个爆推模型下,热斑体积压缩比为64,中子产率将有极大的提高,相应的中子产额和能量增益得到提高。离子温度因为主燃料区质量过大,提高不大。提高超热电子能量,或者减小低温主燃料区质量,离子温度将会显著提高。不同的初始离子温度对结果有很大影响,较低的初始温度下更容易得到较高的中子产率和产额。     

Continuous dust monitoring and analysis by spark induced breakdown spectroscopy

Fast monitoring and elemental analysis of suspended dust in air is an important part of health care. In the present paper we attempt to show the capabilities of spark induced breakdown spectroscopy (SIBS) as a simple, rapid, and in situ method for continuous detection and analysis of dust. In this method a high voltage is applied between two electrodes to create plasma in dusty air. Spectral emission of plasma contains qualitative information about the elemental composition of the air. The spectral lines of two major elements of dust, Ca and Mg, are traced as quality criteria of dusty air. To prevent shot to shot fluctuations, the spectral lines of Ca and Mg are normalized to N line available in air. The dust inside the room air is analyzed and compared for two cases of with and without foot traffic. In the subsequent stage, this approach is applied as continuous dust monitoring in a box, which has been simulated under windy weather conditions. The results show that, in the range of laboratory, SIBS has a good sensitivity to monitor variation of dust produced by foot traffic.     

Nonlinear theory of combustion stability in liquid rocket engine based on chemistry dynamics

Detailed models of combustion instability based on chemistry dynamics are developed. The results show that large activation energy goes against the combustion stability. The heat transfer coefficient between the wall and the combust gas is an important bifurcation parameter for the combustion instability. The acoustics modes of the chamber are in competition and cooperation with each other for limited vibration energy. Thermodynamics criterion of combustion stability can be deduced from the nonlinear thermodynamics. Correlations of the theoretical results and historical experiments indicate that chemical kinetics play a critical role in the combustion instability.     

Reclamation of Used Engine Oil

Used lubricating oil from vehicles was treated with various types of chemicals to be regenerated. It was found that used lubricating oil could be reclaimed with sulphuric acid, sodium hydroxide, sodium phosphate, ammonium sulphate and rosin. Viscosity and pour point of the reclaimed lubricating oil were improved with the additive methyl methacrylate. The reclaimed lubricating oil was characterized by four‐ball ma chine and it was found that wear scar diameter (WSD) has greatly been de creased with the reclamation. The results of atomic absorption spectrophotometer also show that wear metals have also been de creased to an appreciable amount in there claimed lubricating oil.     

原子荧光光度计在砷测定过程中出现的一例故障及故障排除方法

介绍了原子荧光光度计中原子化器温度降低在砷测定过程的故障现象、故障诊断及故障排除方法。阐述了由于测定原理不同,原子化器温度降低对砷、硒、汞检测影响的差异。