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Production of atmospheric pressure non-equilibrium plasma with microwave and applications for plasma processing

微波制备大气压非平衡等离子体及其在等离子体处理中的应用

基本信息

批准号：
16540451
负责人：
YONESU Akira
金额：
$ 2.3万
依托单位：
University of the Ryukyus
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

We have developed a new type of microwave plasma source which can produce a non-equilibrium cold plasma at atmospheric pressure. In this apparatus, plasma was produced in the quartz glass pipe surrounded by slit aluminum pipe which works as the microwave antenna. It was found that the discharges were stable and reproducible at wide gas pressure range from 10 Pa to atmospheric pressure. It was observed that the plasma uniformly spread over the discharge quartz pipe (diameter 20mm, length 300mm) even at atmospheric pressure. The gas temperatures of approximately 500℃ and the electron temperature of 1〜2eV have been obtained. This indicates that non-equilibrium cold plasma was produced in this apparatus.The characteristics of the atmospheric pressure non-equilibrium plasma produced by pulse-time-modulated microwave have been investigated. The gas temperature measured by a thermocouple in pulse modulated mode plasma was about 350℃ at the pulse period of 2msec and 0.8 duty ratio, whereas that obtained in the continuous wave (CW) mode plasma was about 500℃ with same time-averaged microwave power of 800W. On the other hand, the time-averaged ion saturation current in pulse modulated mode plasma was comparable to that of CW mode plasma.We have developed an atmospheric pressure ejected plasma (plasma torch) source for processing arbitrary shaped objects. The gas temperature of about 400℃ and the flame length of about 40mm have been obtained. This system has produced plasmas using a variety of gases and gas mixture, including argon, helium, oxygen and nitrogen at atmospheric pressure. This system has been applied to the sterilization of micro-organisms on the plastic plate. Small amounts of O_2 gas was added into argon plasma as reactive species for oxidizing. The killing of all micro-organisms can be accomplished in a few seconds by direct exposure to the active species of this system.

我们研制了一种新型的微波等离子体源，它能在大气压下产生非平衡冷等离子体。在该装置中，等离子体产生的石英玻璃管周围的狭缝铝管作为微波天线。结果发现，放电是稳定的和可重复的，在宽的气体压力范围从10帕到大气压。观察到，即使在大气压下，等离子体也均匀地分布在放电石英管（直径20 mm，长度300 mm）上。获得了约500℃的气体温度和1 ~ 2 eV的电子温度。研究了脉冲时间调制微波产生的大气压非平衡冷等离子体的特性。当脉冲周期为2 ms，占空比为0.8时，在脉冲调制模式下，用热电偶测得的气体温度约为350℃，而当微波时均功率为800 W时，在连续波（CW）模式下测得的气体温度约为500℃。另一方面，脉冲调制模式等离子体中的时间平均离子饱和电流与连续波模式等离子体中的时间平均离子饱和电流相当。我们研制了一种用于加工任意形状物体的大气压喷射等离子体（等离子体炬）源。获得了400℃左右的燃气温度和40 mm左右的火焰长度。该系统在大气压下使用各种气体和气体混合物产生等离子体，包括氩气、氦气、氧气和氮气。该系统已应用于塑料板上微生物的灭菌。在氩等离子体中加入少量O_2气体作为反应物种进行氧化。通过直接接触该系统的活性物质，可以在几秒钟内杀死所有微生物。