中文摘要：

为研发新型微波液相放电技术，探究电极匹配理论及微波液相放电等离子体的形成机理，采用微波匹配理论设计了一种新型微波液相放电系统，利用网络分析仪来检测放电电极结构发生变化时的驻波比变化情况；对放电电极进行正置与侧置，通过图像分析研究了气泡走向对放电特性的影响；基于微波液相放电形成机理，采用气泡击穿理论研究了温度对气泡及放电特性的影响。结果表明，影响放电电极匹配的主要参数为内外导体的尺寸、内外导体间介质的相对介电常数以及电极所处溶液的相对介电常数。放电过程中，气泡的走向对等离子体的产生区域有着重大影响，微波液相放电过程实际上是电极内导体尖端气泡被强电场击穿的过程。此外，随着温度的升高，放电前所产生的气泡逐渐增大，起始功率呈减小趋势，放电等离子体区域出现先增大后减小的现象。

英文摘要：

In order to develop a new method for generating microwave discharge in liquid （LMD）, to research the me- chanism of this discharge and the matching theory of electrodes, we put forward experiments and corresponding theoretical analysis. Firstly we designed a new system of LMD based on the matching theory of microwave. With the system and a network analyzer, we measured the ratio of standing wave when the electrode structure of discharge system changes. The processes of microwave discharge are filmed with the discharge electrode positioned vertically and horizon- tally respectively. The obtained images are used to analyze the effect of bubble movement on LMD. Plus, based on the formation mechanism of LMD and the breakdown theory of bubble, the effects of temperature on bubble generation and discharge were also investigated. The results showed that the size of the inner and outer electrodes, the relative dielectric constant of the medium between the inner and outer electrodes, and the relative dielectric constant of liquid around the discharge electrode are the main parameters affecting the matching of discharge electrode. In the discharge process, the movement of bubbles significantly influences the area generating plasma. In fact, the process of LMD is the breakdown process of bubbles over the cutting-edge of inner electrode induced by strong electric field. Moreover, with rising temper- ature, the size of bubble generated increases gradually and the initial power before LMD tends to decrease, in the meantime the area of discharge plasma firstly increases and then decreases.