大气压氩氧脉冲介质阻挡放电等离子体中长生存时间活性氧粒子的演化机理

Evolution Mechanisms of Long-lived Reactive Oxygen Species in Atmospheric-pressure Pulsed Dielectric Barrier Discharges in Ar/O2

大气压脉冲介质阻挡放电等离子体中,活性氧粒子的生成和调控对于等离子体在生物医学中的应用具有重要意义,而活性氧粒子的生成和调控又与他们在放电中密度的时空演化密切相关。因此,研究活性氧粒子在1个放电周期中随时间的演化十分必要。使用1维流体模型,模拟研究了氧气体积分数为1%情况下大气压氩氧脉冲介质阻挡放电等离子体中,所考虑的各粒子的空间平均粒子数密度在1个完整周期内随时间的变化。结果表明：电子e、Ar~＋、Ar_r、Ar_m和Ar＊等粒子均主要生成于脉冲的上升沿和下降沿,并随脉冲的关断继续演化而后缓慢衰减至0,而O、O_2（~1Δg）和O_3 3种活性氧粒子在脉冲关断以后仍大量存在于气隙中。因此,针对具有长生存时间的O、O_2（~1Δ_g）和O_3粒子,进一步研究了他们在1个完整脉冲周期内的生成与消耗途径及随脉冲参数的变化,分析了相应的机制。

In the atmospheric-pressure pulsed dielectric barrier discharge, the generation and regulation of reactive oxygen species are of essential importance for their applications in biomedicine and are closely related to the variety of their densities with time in a pulsed period. Hence, it is of necessity to investigate the temporal evolution of reactive oxygen species in a discharge period. We investigated the temporal evolutions of the averaged particle densities of the considered species in the atmospheric-pressure pulsed dielectric barrier discharges in Ar/O2 by means of the numerical simulation based on a 1-D fluid model at oxygen concentration of 1%. The following significant conclusion can be drawn. Electron e, Ar＋, Arr, Arm and Ar＊ are generated mainly at the rising and falling edges of the applied voltage pulse and are consumed rapidly in the pulse-off time, while reactive oxygen species O, O_2（~1Δg） and O_3 still exist largely in the gap in the pulse-off time. Thereby, the pathways of generation and loss of the long-lived reactive oxygen species, i.e., O, O_2（~1Δg） and O_3, have been further investigated, and the averaged particle densities of them as a function of the parameters of the applied voltage pulse have also been calculated, giving the corresponding mechanisms.