【作者】 邓续周；

【导师】 张善端；

【作者基本信息】 复旦大学 ， 等离子体物理， 2008， 硕士

【摘要】 大气压强下的均匀辉光放电在材料表面改性、等离子体灭菌等领域有广阔的应用前景。第一章回顾了大气压均匀辉光放电的研究历史和现状，比较了普通金属板电极、多针-平板电极、金属网电极以及水电极等几种放电装置。第二章设计了平板电极、梳状电极和真空水电极等三种放电装置。用平板电极的体放电和梳状电极的面放电进行了等离子体灭菌实验。在真空玻璃箱内利用水电极实现了亚大气压条件下的介质阻挡均匀辉光放电。第三章主要比较了高气压（15-760 Torr）条件下均匀辉光放电和丝状放电的电压、电流波形以及光谱强度，在此基础上提出了判断均匀辉光放电的判据。氦气、氩气均匀放电时在每半个周期内出现单电流脉冲；但随着电压的升高，电流脉冲的数目增加，幅度降低。在氩气丝状放电中同样有此现象，这表明电流波形与放电均匀性没有必然的关系。周期性出现的单电流脉冲无法作为高频下均匀放电的普适性判据。分析了放电照片的灰度均匀性，认为它可以作为判断均匀放电的定量参数。实验测量了不同气压下氩放电的发射光谱，发现高气压下由于下能级的吸收增加，氩750-850 nm的部分谱线强度反而比低气压时降低。第四章分析了气压、电极间距、水蒸汽和氧气等因素对实现均匀放电的影响，探讨了辉光放电转为丝状放电的气压阈值，以及由丝状放电过渡到均匀辉光放电的机理。气压越高，越不容易实现均匀放电。各种气体的均匀放电的气压上限分别是Ar（760 Torr），Ar-O₂（600 Torr,O₂％=5％），N₂（525 Torr），N₂-O₂（375 Torr,O₂％=20％），空气（300 Torr）。电负性的O₂和H₂O会吸附自由电子，将提高击穿电压，影响放电的均匀性。更多还原

【Abstract】 Uniform glow discharge at atmospheric pressure is widely used in surface modification and plasma sterilization. The history and status of research on the uniform glow discharge at atmospheric pressure are summarized in Chapter 1, where also includes a comparison for some different electrode modes such as metal panel electrodes, multi-pin-panel electrodes, mesh electrodes, and water electrodes.Chapter 2 describes three types of discharge instruments with panel electrodes, comb electrodes and water electrodes. Experiments of sterilization were conducted in plasmas that were produced by volume discharge with panel electrodes and surface discharge with comb electrodes. A water electrode was used to realize dielectric barrier uniform glow discharge at sub-atmospheric pressure in a vacuum glass cavity.In Chapter 3, the waveform of discharge voltage, current and intensity of emission spectrum for uniform glow discharge and filamentary discharge at high pressure (15-760 Torr) are compared. A criterion of uniform glow discharge is proposed. A pulse appears in the half cycle of current in uniform glow discharge of helium and argon. But with the increase of voltage, the numbers of current pulses increase and pulse amplitude decrease. The same phenomenon was observed in filamentary discharge. It was shown that there is no necessary relationship between current waveform and discharge uniformity. The single current pulse in a half cycle can’t be treated as criterion of uniform discharge in high frequency operation. The fluctuation of grey scale of discharge picture was proposed to be a quantitative parameter for judgment of discharge uniformity. The emission spectrum of argon discharge at different pressure was measured. The results show the intensity of spectral lines within 750-850 nm decreases because the absorption of low-lying energy levels increases at higher pressure.The influence factors such as pressure, discharge gap, water vapor and oxygen molecular in uniform discharge are analyzed in Chapter 4. The mechanism and pressure threshold for the transition from filamentary discharge to uniform glow discharge are discussed. It’s more difficult to obtain a uniform discharge at high pressure. The up limits of pressure for uniform discharge are: argon, 760 Torr; mixture of argon and 5% oxygen, 600 Torr; nitrogen, 525 Torr; mixture of nitrogen and 20% oxygen, 375 Torr; air, 300 Torr. The electronegative oxygen and water molecular will absorb free electrons that lead to the increase of breakdown voltage and un-uniformity.更多还原