关于电磁场理论中电矢势的再认识

经典电磁场理论认为只有电磁场本身有直接的物理意义。运动电荷受到电场力和磁场力的作用,是只有电场强度E和磁感应强度B对运动电荷有作用,而不是电矢势A,在一般人们的观念中电矢势A始终只被看作是数学上的需要而引入的。随着Aharonov-Bohm效应的发现,人们发现对磁场的描述只用B是不够的,它不能解释电子在外磁场中的干涉和散射等现象。带电粒子在外磁场中的动力学行为是否会受到矢势A的直接影响;矢势A的影响是否可以独立于磁感应强度B出现干涉的量子效应,文中将对电磁场理论中电矢势A进行深入分析和探讨,对矢势A进行重新认识并赋以新的定义。     

轴对称静电场不等距多重网格法的研究

研究了不等距多重网格法,可用于区域形状任意和有内电极的实际电子光学系统轴对称电场的计算,特别是对于求解区域大、部分区域电场精度要求高的场合,较好地解决了计算精度与划分网格点数之间的矛盾,可广泛应用于分析设计静电聚焦像管的电子光学系统,以及摄像管电子枪的发射系统等.     

汽油燃烧产物GC-MS分析的萃取剂研究

应用色谱/质谱联用技术对提取93#汽油燃烧烟尘及残留物特征组分的五种萃取剂进行了对比研究。在确保制样过程中汽油组分提取量尽可能一致性的条件下,以提取出的有机特征组分的种类和相对峰面积为标准,利用总离子流色谱图和质量色谱图定性分析了五种萃取剂的萃取效果。     

地球静止轨道高能电子通量在线预测模型研究

利用粒子群优化算法和最小二乘支持向量机,建立了地球静止轨道高能电子通量(1.8-3.5MeV)在线预测模型。针对粒子群优化算法,提出了一种新的粒子群多样性测度计算方法,有效改善了其早熟收敛现象;基于改进的粒子群优化算法优化最小二乘支持向量机的正则化参数和核参数;利用滑动时间窗口策略更新模型数据,设计变量选择触发机制以及模型的再学习机制实现模型的在线预测功能。[根据题目的调整,对摘要做了相应改动]通过对2000年电子通量监测数据和相关太阳风、地磁参数等实际数据进行提前1-3天的预测实验,表明了所建在线预测模型具有较高的预测性能,有一定的实用价值。     

等离子体与高功率微波相互作用中电子分布特性

电子数密度是表征等离子体物理特性的一项重要因素,在等离子体与高功率微波的相互作用中,等离子体对入射电磁波的吸收、衰减和屏蔽等电磁特性可通过电子数密度的变化进行表征。基于等离子体流体近似研究方法,利用COMSOL软件求解等离子体中的波动方程、电子传递方程和重粒子传递方程,计算分析了等离子体与高功率微波相互作用中的电子分布特性,重点分析了相互作用中平均电子数密度和平均电子能的数值和空间分布变化过程。研究表明,在高功率微波作用下,等离子体区域电子数密度在数值上会产生剧烈的阶跃变化,形成雪崩效应,在空间分布上电子数密度峰值产生趋于入射方向移动的变化;电子能的变化与入射波激励和电子数密度相关,随入射激励增加呈增长趋势,随电子数密度的增加而减小。     

Effect of bending temperatures on the microstructure and springback of a TRIP steel sheet

Transformation-induced plasticity (TRIP) steel possesses high strength and formability, enabling the use of a thinner gauge material and allowing for the fabrication of complex shapes. In this research, we measured the effect of bending temperatures on the microstructure and air-bending springback angle of TRIP steel at temperatures from 25 to 600 °C. Real-time in situ X-ray diffraction and scanning electron microscopy were used for pre- and postbending analysis. As the prebending temperature increased from 25 °C to 600 °C, the retained austenite (RA) volume fraction decreased, and the RA transformed to bainite at temperatures above 400 °C. The springback angle was positively correlated with the prebending RA volume fraction, with the smallest springback angle achieved at 400 °C. Additionally, the springback angle was positively correlated with the bending angle, because the RA transformation ratio contributed to increased strain hardening. Further microstructure analysis revealed that the RA became elongated in the tension direction as the bending temperatures increased.     

Data-driven prediction of plate velocities and plate deformation of explosive reactive armor

Explosive reactive armor (ERA) is currently being actively developed as a protective system for mobile devices against ballistic threats such as kinetic energy penetrators and shaped-charge jets. Considering mobility, the aim is to design a protection system with a minimal amount of required mass. The efficiency of an ERA is sensitive to the impact position and the timing of the detonation. Therefore, different designs have to be tested for several impact scenarios to identify the best design. Since analytical models are not predicting the behavior of the ERA accurately enough and experiments, as well as numerical simulations, are too time-consuming, a data-driven model to estimate the displacements and deformation of plates of an ERA system is proposed here. The ground truth for the artificial neural network (ANN) is numerical simulation results that are validated with experiments. The ANN approximates the plate positions for different materials, plate sizes, and detonation point positions with sufficient accuracy in real-time. In a future investigation, the results from the model can be used to estimate the interaction of the ERA with a given threat. Then, a measure for the effectiveness of an ERA can be calculated. Finally, an optimal ERA can be designed and analyzed for any possible impact scenario in negligible time.     

圆柱壳体内 X 射线热击波的二维力学计算

依据二维流体弹塑性模型及二维断裂处理方法,研究Ｘ射线热击波在圆柱壳体内的传播规律。计算结果揭示了圆柱壳体内热击波的一些二维效应。     

电感储能型闪光X射线机

电感储能密度比电容高 2～ 3个数量级 ,因此用它制作电感储能闪光X射线摄影机(FXCIES)的脉冲高压电源 ,具有体积小、结构简单和成本低等优点。介绍了FXCIES的电物理设计方法和关键的计算公式。创造出一种新的FXCIES结构 ;高电压形成网络叠在初级电源之上 ,它们都被放置在盛绝缘油的钢壳内 ;爆炸导体断路开关在专门设计的高强度绝缘筒内工作 ,既可提高工作场强又能消声 ;整机全封闭在钢壳内。最后取得了成功的实验结果