脉冲调制大气压等离子体射流亚稳态N2(A，ν=0-2)的激光诱导荧光诊断研究

Atmospheric pressure plasma jet takes the advantages of low cost, near room temperature, at the same time benefits of high freedom of flexible design, which has been currently one of the most active research directions in the field of plasma medicine. However, the related quantitative diagnostic work of long lifetime metastable state N2(A，ν=0-2) is quite scarce, which has been considered to play essential function in plasma chemistry of atmospheric pressure plasma jet. This has become the bottleneck of corresponding mechanism research. Therefore, in this project, we will utilize the high spatial and temporal resolved ability of laser induced fluorescence spectroscopy method, combined with abundant high-voltage drive scheme such as single pulse, multi-pulse by pulse-modulated AC technology and DC nanosecond pulse technology, to perform measurements of long lifetime metastable state N2(A，ν=0-2) in atmospheric pressure plasma jet. The specific effects on the generation, quenching and the transport process of N2(A，ν=0-2) will be explored. And by using the cross validation of different discharge schemes, the production, quenching mechanism of N2(A，ν=0-2) will be clarified. This work will provide experimental basis and support for developing atmospheric pressure plasma jet for biomedical applications.

大气压射流放电等离子体具有低成本、近室温等优势，同时具备较高的“柔性”设计自由度，是当前等离子体生物医学技术领域的热门研究课题之一。然而，目前对于在射流放电等离子体化学过程中起重要作用的氮气亚稳态物种关注不够，定量诊断工作十分稀少，使得相应的机理研究工作遇到瓶颈。鉴于此，本项目利用激光诱导荧光光谱诊断技术的高时空分辨能力，针对大气压射流放电，结合脉冲调制的交流放电技术和直流纳秒脉冲放电技术，开展长寿命亚稳态N2(A，ν=0-2)的定量研究，细致研究单脉冲、多脉冲、直流、交流等丰富的高压激励方案对N2(A，ν=0-2)的生成、饱和、淬灭过程及输运过程的具体影响，利用不同放电方案的交叉验证，明确其产生、淬灭机制。本项目的研究成果将为发展射流放电等离子体源的生物医学应用提供实验数据支撑。

大气压射流等离子体在等离子体生物医学领域有巨大的应用潜力。项目执行中课题组分别测试了大气压针-环电极等离子体射流装置和双环结构射流装置，以调控放电均匀性和活性物种分布。考察了脉冲调制交流放电和直流脉冲放电方案对大气压射流等离子体的发射光谱时空分布的影响。通过平面激光诱导荧光（P-LIF）技术对大气压射流装置中的OH自由基进行了测量，以实现荧光探测装置的标定和优化。调整了N2(A，ν=0-2)物种激光诱导荧光检测方案，尝试利用iCCD高速相机对氮气亚稳态物种N2(A，ν=0-2) 进行时空分辨平面LIF成像。研究结果表明，大气压环境粒子碰撞频繁，N2(A，ν=0-2)淬灭较快，荧光产量过低，需配合高灵敏度PMT对单点亚稳态浓度进行监测，直观调节N2(A，ν=0-2)的物种产量，再过渡到N2(A，ν=0-2)物种的P-LIF测量。此外课题组利用大气压射流制备等离子体活化水（PAW），评价了活化水对大肠杆菌的灭活效果。分别研究了两种不同储存条件以及等离子体射流注入功率对PAW灭活大肠杆菌的影响。同时利用项目开展过程中积累的技术手段对相关领域进行了适当的延伸和拓展，开展了大气压沿面放电结构OH基态自由基分布与电极尺寸的关联研究，考察了阵列间距和网格电极线宽对OH自由基分布区域的时间演化及输运过程的影响。