光源在光学实验中的应用

本文对大学物理光学实验中常用光源做简单介绍,使学生明确不同的光源用于不同的实验目的。     

棒-板电极下缩比气隙辉光放电相似性的仿真研究

建立了棒-板电极下氩气直流放电的流体模型,利用有限元法对几何位形相似的两个气隙放电过程进行了数值求解.两放电气隙外加电压相同,气隙线性尺寸的比值为10:1,气压分别为1 Torr和10 Torr.仿真得到了两相似气隙的放电的伏安特性曲线以及放电物理量(如电位、电场、电子密度、离子密度、电子温度等)的空间分布.根据气体放电相似性的基本结论,检验了气隙对应物理量之间的数值关系.结果表明:两相似气隙的放电类型为正常辉光放电,对应放电物理量之间存在相似性理论指出的比例关系,且在相同幅值的直流电压作用下,气隙放电的工作点相同.这将为利用气体放电相似性来外推相似气隙的放电特性提供一定的理论依据.     

探究轻质塑料桶在尖端附近的旋转现象

基于轻质塑料桶在尖端放电时旋转方向的不一致现象提出问题,利用酒精灯火焰来显示带电粒子的流动方向,并探究在接地尖端附近粒子运动的异常现象。实验发现,接地端也存在放电现象。     

The characteristics analysis of a new-style four-mirror axisymmetric-fold-combination cavity adapting to cylindrical discharge region

An axisymmetric-fold-combination (ASFC) cavity composed of two planar mirrors and spherical mirrors was designed. It is a stable-unstable resonator cavity. The light field of radial direction is Gaussian distribution. And in angular orientation, the distribution keeps invariant. It could generate annular CO₂ laser beam with excellent spatial coherence. And the spatial coherence is commendably realized with its stable-unstable cavity structure. The output light intensity distribution of this special model was discussed and simulated. With exterior lenses group, the output beams can be adjusted and controlled better to meet the manufactural requirements. Some references were provided for further research of the cavity with cylindrical discharge region.     

氟化氙(C-A蓝绿激光技术研究进展

 综述了XeF(C-A)激光的产生原理，表面放电光泵浦源的结构，激光器装置， XeF(C-A)激光实验研究以及XeF(C-A)激光理论模拟；介绍了XeF₂浓度的监测，以及表面放电光泵浦源技术研究的最新进展。     

微波瑞利散射法测定空气电火花激波等离子体射流的时变电子密度

大气压空气电火花激波等离子体射流的电子密度在亚微秒时间尺度上瞬变,其电子密度的测定很难.基于微波瑞利散射原理,本文测量了空气电火花冲击波流注放电等离子体射流的时变电子密度.实验结果表明:测量系统的标定参数A为1.04 × 105 V·Ω·m–2;空气流注放电等离子体射流的电子密度与等离子体射流的半径和长度有关,结合高速放电影像展示的等离子体射流的等效半径和等效长度,测定的电子密度在1020 m–3的量级,且随时间先快速增长至峰值再成指数衰减.此外,本文还探讨了等离子体射流的不同等效尺度对测定结果的影响;分析结果表明,采用时变等效半径和时变等效长度的计算结果最有效,且第1个快速波峰是由光电离的电离波导致的.     

放电脉冲重频准分子激光器在不同应用领域的发展现状(英文)

研究了脉冲宽度为25～40 ns的放电脉冲XeCl准分子激光器的工作参数。结果显示,激光器产生的脉冲能量为0.2～0.7 J,重复频率为100 Hz,表明在泵浦功率为2.8～3.3 MW/cm3时,激光器实现了2.6%的激光效率和3.8%的本征效率。     

Corona-induced graft polymerization for surface modification of porous polyethersulfone membranes

Graft polymerization of acrylic acid (AA) onto porous polyethersulfone (PES) membrane surfaces was developed using corona discharge in atmospheric ambience as an activation process followed by polymerization of AA in aqueous solution. The effects of the corona parameters and graft polymerization conditions on grafting yield (GY) of AA were investigated. The grafting of AA on the PES membranes was confirmed by ATR-FTIR and X-ray photoelectron spectroscopy (XPS) analysis. Porosimetry measurements indicate the average pore diameters and porosities of the modified membranes decrease with the increase of the GY. The hydrophilicity and surface wetting properties of the original and modified membranes were evaluated by observing the dynamic changes of water contact angles. It is found that the grafting of AA occurs not only on the membrane surfaces, but also on the pore walls of the cells inside the membrane. The permeability experiments of protein solution reveal that the grafting of PAA endows the modified membranes with enhanced fluxes and anti-fouling properties. The optimized GY of AA is in the range of 150-200 μg/cm². In addition, the tensile experiments show the corona discharge treatment with the power lower than 150 W yields little damage to the mechanical strength of the membranes.     

Enhancement of soft X-ray emission from a pinch plasma using a rotating plasma for pre-ionization

An experimental study on the enhancement of soft X-ray emission from a pinch plasma has been carried out by using a rotating plasma for pre-ionization. The rotating plasma is produced by a pulsed J×B cross-field discharge between coaxial electrodes, and subjected to a pinch discharge. Under an optimized discharge condition, it has been observed that UV emission of 251.6 nm (Ar III) soft X-ray intensity increases with increasing applied axial magnetic field B. At 400 G, the X-ray intensity is enhanced by a factor of 3 compared to that without the rotating plasma. It is considered that this result is due to the improved characteristics of the pre-ionization rotating plasma, which influences the uniformity and stability of subsequent pinch plasma.     

常压DBD二维流体模型的FCT方法数值模拟

根据常压介质阻挡放电流体模型的物理方程,采用固定网格有限差分算法,分别用四阶和六阶相位误差FCT方法模拟求解二维流体连续方程.在均匀的初始条件下研究放电雪崩过程中电子密度的时空演化,具体分析和比较两种算法的差异.FCT方法模拟求解得出的计算结果与气体放电理论吻合较好,是一种具有较好的准确性和高精度的算法.