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准分子激光器是强紫外输出的高效率器件,由于它在激光化学、大规模集成电路及生物领域内的应用价值,已受到普遍重视.当前国内已有一些器件逐渐开始走出实验室,但某些性能还不够理想,有待进一步改进.双重预电离准分子激光器的研制对提高器件的性能有着直接的或间接的意义.因为在准分子激光器中预电离的效果对器件的性能影响很大,电晕和紫外双重预电离技术可以得到比较充分的预电离,使激光腔中高气压大体积放电更为均匀和稳定,对增加激光输出能量、降低输出能量的不稳定性以及提高整体效率都是极为重要的,也有助于高重复率器件的研制. 图1表示… 相似文献
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以超声的热弹激发机理为基础,建立了模拟激光在管道中激发周向导波的有限元模型.为了验证模型的正确性,根据Gao等人报道的实验条件[J. Appl. Phys. 91, 6114 (2002)]进行了模拟,理论模拟结果与Gao等人的实验结果符合很好,说明本数值模型的正确性.在此基础上,模拟激光在不同厚度、不同曲率半径的管道内激发的周向导波波形,同时分析了激光在管道中激发的周向导波波形与平板中激发Lamb波的差异,以及管道厚度和曲率半径对激光激发周向导波的影响. 相似文献
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In this paper, the compositions in a laser absorption region can be determined from the experiment of laser impulse coupling. When the ambient pressure varies from 9325 to 33325Pa, the compositions are vapour and plasma; while from 35325 to 101325Pa, they are ambient air and plasma. By analysing the relation between the degree of compression and the ambient pressure, the compositions can be determined and the variation of plasma can be explained. 相似文献
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Theoretical analysis and numerical simulation of the impulse delivering from laser-produced plasma to solid target 总被引:1,自引:0,他引:1 下载免费PDF全文
A plasma is produced in air by using a high-intensity Q-switch Nd:YAG pulsed laser to irradiate a solid target, and the impulses delivering from the plasma to the target are measured at different laser power densities. Analysing the formation process of laser plasma and the laser supported detonation wave (LSDW) and using fluid mechanics theory and Pirri's methods, an approximately theoretical solution of the impulse delivering from the plasma to the target under our experimental condition is found. Furthermore, according to the formation time of plasma and the variation of pressure in plasma in a non-equilibrium state, a physical model of the interaction between the pulse laser and the solid target is developed. The plasma evolutions with time during and after the laser pulse irradiating the target are simulated numerically by using a three-dimensional difference scheme. And the numerical solutions of the impulse delivering from the plasma to the target are obtained. A comparison among the theoretical, numerical and experimental results and their analyses are performed. The experimental results are explained reasonably. The consistency between numerical results and experimental results implies that the numerical calculation model used in this paper can well describe the mechanical action of the laser on the target. 相似文献
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Comprehensive numerical and experimental analyses of the effect of viscosity on cavitation oscillations are performed. This numerical approach is based on the Rayleigh-Plesset equation. The model predictions are compared with experimental results obtained by using a fibre-optic diagnostic technique based on optical beam deflection (OBD). The maximum and minimum bubble radii as well as the oscillation times for each oscillation cycle are determined according to the characteristic signals. It is observed that the increasing of viscosity decreases the maximum bubble radii but increases the minimum bubble radii and the oscillation time. These experimental results are consistent with numerical results. 相似文献
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卟啉是生命活动的重要物质,原卟啉可做为肿瘤血液标志物.人血清中血卟啉含量很低,且受多种因素影响.基于小波变换的人血清血卟啉荧光光谱分析法可实现对其弱信号的分辨.用多功能光谱测量系统获取人血清血卟啉荧光光谱,对获取的荧光光谱通过数次小波变换进行分解,将噪声与光谱信号分离,滤波后的荧光光谱进行6次分解后得到了离散逼近信号(a1~a6)和离散细节信号(d1~d6).信号频率随着分解次数的增加逐步降低.当分解到第6次时,出现了血卟啉荧光特征峰,成功地观测到血卟啉的荧光发射峰,实现了弱信号分辨,得到了血清中所含血卟啉的准确成份和定量信息,从而进行定性和定量分析,为血清荧光光谱用于肿瘤的早期诊断提供了一种方法. 相似文献
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将高功率脉冲激光作用于金属元靶产生等离子体,实验测试了并分析了靶上电势信号的时间演变规律及其成因,同时实验研究了激光能量、靶材料、靶结构等因素对靶上电势信号的影响. 相似文献
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在准真空环境下,采用高功率密度的调Q-Nd:YAG激光照射固体铝靶表面,测量了不同入射激光强度下气化靶物质对靶的冲量.通过分析不同情况下激光与固态靶、气化物质的作用机理,采用流体力学理论和三维有限差分的计算方法,对不同激光强度情况下气化物质对靶产生冲量的过程进行了数值模拟,将模拟计算所得结果与实验测量结果进行了比较和分析,进而对实验结果进行了解释.由数值模拟结果与实验结果的一致性可见,本文采用的模型能反映激光作用下固体靶力学响应的物理过程. 相似文献