Study on high frequency discharge containing oxygen at atmospheric pressure

首次研究了采用时调制电源的平面盘式阻挡放电的臭氧产生效率。使用时调制电源获得的效率比使用直流电源获得的效率高，该效率是注入放电功率的递减函数。为了获得最高效率，所需的最佳接通时间对应于正弦电压的一个周期，而电源的断开时间需要超过10-15 ms。其次，对大气压下电容耦合射频（13.56 MHz） He/O_2放电进行了电学和光学测量。He放电中氧的添加量从0%到5%不等。在任何条件下，耗散功率对放电电压的依赖性都可以产生明显的变化。受激氧原子发射的845 nm谱线的强度（由受激Ar发射的750.4 nm谱线强度和基态Ar密度与中性物质总密度之比归一化）作为耗散功率的函数进行了研究，而臭氧浓度则通过254 nm处的光吸收来检测。归一化强度与耗散功率近似成正比，而臭氧密度随功率的增加而降低。比较了电容耦合射频He/O_2放电与He/O_2阻挡放电的臭氧产生量，探讨了射频He/O_2放电作为臭氧发生器的可能性。虽然射频放电的臭氧形成效率低于阻挡放电，但使用时调射频电源获得的臭氧形成效率显著提高，其值从约4g/kWh增加到约80g/kWh。

Ozone production efficiency of a planar-disk-type barrier discharge of oxygen using a time-modulated power supply was first investigated. The efficiency obtained using the time-modulated power supply, which was a decreasing function of power injected into the discharge, was higher than that obtained using a C.W. power supply. The optimum on-time required in order to obtain the maximum efficiency corresponded to one period of the sinusoidal voltage, while an off-time of the power supply longer than 10-15 ms was required.Second, electrical and optical measurements on capacitively-coupled radio frequency (13.56 MHz) He/O_2 discharges at atmospheric pressure were carried out. The addition of oxygen to the He discharges varied from 0% to 5%. A distinct change in the dependence of the dissipated power on discharge voltage can be induced in any conditions. The intensity of the 845 nm line emitted from excited oxygen atoms, which was normalized by the intensity of the 750.4 nm line emitted from excited Ar and the ratio of the ground state Ar density to the total density of neutral species, was investigated as a function of the dissipated power, whereas the ozone concentration was detected by the optical absorption at 254 nm. The normalized intensity was approximately proportional to the dissipated power, whereas the ozone density decreased as the power increased. The ozone production in the capacitively coupled RF He/O_2 discharges was compared with that in He/O_2 barrier discharges in order to research the possibility of the RF He/O_2 discharges as the ozone generator. Although the ozone formation efficiency in the RF discharges was lower than that in the barrier discharges, the formation efficiency obtained using a time-modulated RF power supply was drastically improved and its value increased from about 4g/kWh to about 80g/kWh.