向内发射同轴虚阴极振荡器的优化

为提高虚阴极振荡器微波能量转换效率,使用2.5维全电磁P IC(particle in ce ll)软件对向内发射同轴虚阴极振荡器进行数值模拟,优化设计了阳极反射板与阴极发射区之间距离D,并研究了阳极网透射区宽度B对能量转换效率的影响。模拟发现:选取适当的D值可提高效率,同时随着B的增大,能量转换效率逐渐增大并趋近一稳定值。模拟所得微波振荡主频与理论值符合较好。优化结果为:在阴、阳极半径分别为7 cm和5.5 cm,二极管电压250 kV,电流20 kA条件下,得到主频3.45 GH z,3 dB带宽约3%,微波功率310MW,能量转换效率6.8%的窄带微波输出。     

3-D Design and Numerical Simulation of Two-Phase Flow in the Laser Rapid Prototyping Coaxial Powder Delivery System

The metal powder direct and rapid prototyping technology is one of the most developing methods in the laser rapid prototyping technique. The coaxial powder delivery system is the key technique. The purpose of this paper is to introduce a new type of coaxial powder delivery system and simulate the metal powder and shield gas flow in the powder nozzle. 2-D and 3-D model of the new coaxial powder delivery system are established. Then gas-solid two-phase flow model and the k-ε turbulent model are selected to simulate the flow of metal powder in powder nozzle. The Euler-Lagrange method is used in the simulating computation. The results show that the new coaxial powder delivery system has stable performance, uniform powder flux, high cooling efficiency, and long useful life.     

同轴谐振腔及微扰法测量介质介电常数

提出了一个新的具有设计性与综合功能的微波测量实验项目，利用同轴谐振腔，接合理论对介质的ε′、ε″及tanδ、加载腔端电容C进行测量与计算，并在学校电磁场与微波技术专业进行了教学实践，取得了良好的教学效果。     

Distributed capacitance of coaxial line with perturbed walls

Perturbation method of boundary geometry (PMOBG) used in Laplacian problems is dealt with and the three-term perturbation expression of, distributed capacitance of a coaxial line with perturbed walls is obtained. As an example, four-order expression of distributed capacitance of a elliptic coaxial line with small eccentricity is given. Foundation item: Supported by the Open Foundation of State Key Laboratory of advanced Technology for Materials Synthersis and Processing Biography: Peng Bao-quan (1943-), male, Associate professor, Research direction electromaganetic field theory and digital signal processing     

用EGSnrcMP蒙特卡罗程序研究单能电子吸收实验中的影响因素

运用EGSnrcMP蒙特卡罗程序模拟了不同能量单能电子在铝吸收体中的吸收,画出吸收曲线,并将模拟结果与实验结果进行比较.在模拟条件与实验条件一致的情况下,模拟值与实验值得到了很好的符合.本文还通过改变模拟计算的条件,讨论了实验条件对电子吸收规律测量的影响.     

合肥光源深X-射线光刻模拟

论文对合肥同步辐射光源开展深度X-射线光刻进行了理论模拟。利用Gauss积分法研究了菲涅耳衍射对深度光刻图形精度的影响。为了模拟衬底产生的光电子对光刻结果的影响，构建了一个Monte Carlo模型并进行了模拟。计算结果表明，合肥光源深度光刻的图形精度较高。     

半柔性同轴电缆外导体垂直镀锡工艺及其关键工艺参数

在外导体（铜丝编织网）上进行整体镀锡是目前制造半柔性同轴电缆的关键工序之一．目前的水平镀锡工艺存在着锡层表面针孔多、锡层易脱落和生产效率低等缺点．为了解决目前镀锡工艺存在的问题,提出了一种外导体垂直镀锡新工艺．垂直镀锡工艺可以将同轴电缆浸入锡液的长度缩短至10～100mm,同轴电缆在高温锡液中的停留时间减少到1．0S以下．通过减少电缆在高温锡液中的浸入长度和停留时间可以显著减少气孔缺陷的发生,同时提高了镀锡层的质量和生产效率．通过实验发现,锡液温度控制在255～265℃,电缆在锡液中的停留时间控制在0．5—1．0S以内,浸锡深度在40—80mm之间,配合4～6m／min的电缆送进速度,可以得到无气孔缺陷的高质量镀锡层．     

Energetic electrons associated with magnetic reconnection in the sheath of interplanetary coronal mass ejection

Magnetic reconnection is an important universal plasma dissipation process that converts magnetic energy into plasma thermal and kinetic energy,and simultaneously changes the magnetic field topology.In this paper,we report the first observation of energetic electrons associated with asymmetric reconnection in the sheath of an interplanetary coronal mass ejection.The magnetic field shear angle was about 151°,implying guide-field reconnection.The width of the exhaust was about 8×104 km.The reconnection rate was estimated as 0.044-0.08,which is consistent with fast reconnection theory and previous observations.We observed flux enhancements of energetic electrons with energy up to 400 keV in this reconnection exhaust.The region where ener- getic electron fluxes were enhanced is located at one pair of separatrices in the higher density hemisphere.We discuss these observation results,and compare with previous observations and recent kinetic simulations.     

Al含量对Fe-Al合金中微观缺陷和价电子密度的影响

测量Ｆｅ２８Ａｌ和Ｆｅ４０Ａｌ合金的正电子寿命谱参数,计算合金基体和缺陷处的价电子密度。Ｆｅ２８Ａｌ和Ｆｅ４０Ａｌ合金基体的价电子密度（ｎｂ）分别为４１０×１０－２ａｕ和２３６×１０－２ａｕ,表明当Ａｌ和Ｆｅ结合形成Ｆｅ２８Ａｌ或Ｆｅ４０Ａｌ合金时,Ａｌ原子提供价电子与Ｆｅ原子的３ｄ电子形成局域的共价键,Ｆｅ２８Ａｌ和Ｆｅ４０Ａｌ合金中金属键和共价键共存。两种合金均有开空间大的缺陷,晶界缺陷处价电子密度（ｎｄ）〔１３２×１０－３ａｕ（Ｆｅ２８Ａｌ）,４７０×１０－３ａｕ（Ｆｅ４０Ａｌ）〕比基体的低,表明晶界处的键合力较弱。Ｆｅ４０Ａｌ合金晶界缺陷的开空间比Ｆｅ２８Ａｌ的大。     

BCB介质层同轴TSV的热力学仿真分析

穿透硅通孔（through silicon via,TSV）的热机械可靠性问题已经成为制约TSV市场化应用的重要因素.本文对BCB介质层同轴TSV的热力学特性进行了研究分析,同时对其几何参数（SiO₂绝缘层厚度、屏蔽环厚度、TSV间距、中心信号线半径）进行了变参分析,为降低热应力提供指导意见.结果表明,在阻抗匹配的前提下,通过增加SiO₂绝缘层厚度、减小屏蔽环厚度能够有效降低同轴TSV的诱导热应力;相比之下中心信号线半径和TSV间距的变化对其影响可忽略不计.