大电流稳定发射铁电阴极的模拟与实验研究

讨论了铁电阴极的发射机理, 借助MAFIA对不同电极结构的铁电阴极表面电场分布进行了模拟计算. 计算中发现, 发射面电极结构对铁电阴极表面三界点处的场增强效应影响很大,特别是具有孤岛电极结构的铁电阴极具有更大的三界点场强,从而获得更大和更稳定的发射电流. 通过对电极结构及其工艺的改进,使用PLZT铁电阴极在实验中得到了大于100A的电流.     

微脉冲电子枪的初步实验研究

给出了微脉冲电子枪的模拟计算及其初步实验结果. 该电子枪采用铜铝镁合金作为冷阴极材料, 在以磁控管作为微波功率源的出束实验中得到了100mA/cm²的电流密度.实验结果与次级电子倍增解析计算和SEEG程序的模拟计算结果基本符合, 初步验证了微脉冲电子枪的基本原理, 为今后实验中得到更大的电流密度打下了基础.     

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在四阳极直流放电装置上,测量并分析了辉光放电的电流-电压和发光特征随气压的变化关系。结果表明,采用稳流放电模式比稳压放电具有更宽的稳定放电气压和电流范围,能在从1～800Pa的较宽气压范围内实现氦气辉光放电,放电电流可达到500mA左右。随着电极表面亮斑的变化,对于同一气压,在低电流区,放电电压几乎成指数增长;随电流增大,电压的增长速度变缓;对于高的气压,碰撞频率的增大使得电压随电流升高的速率变小。分析表明,放电处于异常辉光区。从放电管的CCD图像可以看出,对于同一放电电流,随气压的升高,等离子体往阴极收缩。     

Mössbauer study on LiFePO4 cathode material for lithium ion batteries

Crystalline LiFePO₄ has been synthesized using solid-state, spray pyrolysis, and wet chemical methods. The crystal parameters were obtained from Rietveld’s refinement methods of the X-ray diffraction patterns. A detailed investigation of the Fe valency carried out using Mössbauer spectroscopy at room temperature indicates that Fe is predominantly present in its bivalent state.     

介质阻挡放电中点线放电的谱线线型及振动温度

在氩气/空气的混合气体近大气压介质阻挡放电中,首次观察到点状与线状放电共存的放电现象, 测量比较了点状与线状放电的谱线频移和振动温度。谱线频移的测量利用的是氩原子ArⅠ(2P₂→1S₅)的发射谱线,振动温度的测量利用的是氮分子第二正带系(C3Π_u→B3Π_g) 的发射谱线。结果表明：点放电中的ArⅠ(2P₂→1S₅)谱线的频移大于线放电谱线的频移,表明前者电子密度较高;而点放电振动温度低于线放电的振动温度。     

常压介质阻挡放电的特性研究及应用前景

常压介质阻挡放电由于其具有均匀、散漫、稳定,而且不需要真空系统等优点,正日益受到人们的重视和研究。文章给出了常压介质阻挡放电的研究进展,包括实验装置、实验条件、放电机理以及最新的诊断方法,还介绍它在材料表面改性、环境工程、食品加工等方面的应用前景。     

CRRFA-30L波段射频加速器

 主要介绍CRRFA-30L波段射频加速器结构和性能，论述了热阴极射频腔注入器、束流加速系统、微波功率源和控制等结构中主要技术及其研究进展，给出了加速器输出束流参数测量与测量结果分析，达到设计应用要求。     

Electron temperature and ion density measurements in a glow discharge of an Ar–N2 mixture

A DC glow discharge produced in N₂ gas can generate several species that are important in different applications, such as the modification of surface properties of materials. A low-pressure glow discharge apparatus was used for the the analysis of the Ar–N₂ mixture at a total pressure of 2.0 Torr, a power of 20 W and 40 l/min flow rate of gases. The emission bands were measured in the wavelength range of 200–1100 nm. The principal elements are N₂, N ₂⁺ and Ar I. The electron temperature was found in the range of 1.72–2.08 eV, and the ion density was in the order of 10¹⁰ cm^?3.     

Radiation hardness of gas discharge tubes and avalanche diodes used for transient voltage suppression

The widespread use of gas discharge tubes (GDTs) and avalanche diodes for transient voltage suppression (TVS) in many cases results in their exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on these TVS devices’ characteristics, by exposing them to a combined neutron/gamma radiation field. Experimental results show that irradiation of TVS diodes causes a lasting degradation of their protective characteristics. On the other hand, GDTs exhibit a temporary change of performance. The observed effects are presented with the accompanying theoretical interpretations, based on the interaction of radiation with materials constituting the investigated devices.     

等离子体尺寸对放电极紫外光源影响

计算了放电等离子体极紫外光刻光源中,不同等离子体长度条件下的收集效率,实验上研究了等离子体长度对Xe气放电极紫外辐射的影响。结合本系统光学收集系统设计参数和理论计算结果,给出了不同等离子体长度条件下中间焦点处13.5 nm（2%带宽）光功率。结果表明等离子体长度为3~6 mm时毛细管光源中间焦点光功率和尺寸最优。