空气和氩气混合气体的双水电极介质阻挡放电装置中, 在电压升高过程中首次发现了两种由亮点和暗点组成的亮暗点菱形斑图。 通过观察斑图照片可以发现: 第一种菱形斑图(菱形斑图Ⅰ)中的暗点处于由亮点组成的菱形单元的中心; 第二种菱形斑图(菱形斑图Ⅱ)中的暗点恰好处于周围其他三个亮点的中心位置。 利用发射光谱法, 通过采集氮分子（N2）第二正带系(C3Πu→B3Πg)发射谱线和氩原子696.54 nm（2P2→1S5）谱线的展宽, 研究了两种菱形斑图中亮点和暗点的分子振动温度和电子密度。 实验发现: 两种菱形斑图中暗点的分子振动温度均高于亮点, 相对菱形斑图Ⅰ来说, 菱形斑图Ⅱ中的亮点和暗点的分子振动温度均升高; 而菱形斑图Ⅰ中暗点的电子密度低于亮点, 菱形斑图Ⅱ中亮点和暗点的电子密度却几乎相等。 两种菱形斑图中电子密度表现出不同的变化趋势, 且在菱形斑图Ⅱ中表现出的规律尤为特殊, 因而采用高速录像机对菱形斑图Ⅱ进行短曝光拍摄观察斑图中亮点和暗点的成分, 发现暗点是体放电和沿面放电共存的状态。 进一步研究从菱形斑图Ⅰ到菱形斑图Ⅱ的演化过程中三种斑图中亮点的电子密度, 结果发现: 演化中间过程的斑图中的亮点的电子密度最大, 菱形斑图Ⅱ中亮点的电子密度最低。 实验结果对于研究斑图的自组织形成过程具有参考作用。

Two kinds of rhombus patterns consisted of the bright spot and dim spot were firstly observed and investigated in discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It was found that dim spot was at the center of four surrounding bright spots in the first kind of rhombus pattern (named rhombus pattern Ⅰ) and the dim spot is at the geometric gravity center of three surrounding bright spots in the second kind of rhombus pattern (named rhombus patternⅡ) by observing the discharge images. The optical emission spectrum method was used to study the several plasma parameters of two kinds of rhombus patterns. The emission spectra of the N2 second positive band（C3Πu→B3Πg） were measured, and the molecule vibration temperature was calculated by the emission intensities. The broadening of spectral line 696.54 nm（2P2→1S5）was used to study the electron densities. The experiment results show that the molecule vibration temperature of the dim spot is higher than that of the bright spot in the two kinds of rhombus patterns, and the molecule vibration temperature and electron densities of the bright spot and dim spot both increase from rhombus patternⅠ to rhombus patternⅡ, while the electron density of the dim spot is lower than that of the bright spot in the rhombus patternⅠ and the electron densities are almost equal in the rhombus patternⅡ. Because the electron densities presents different change trends in two kinds of rhombus patterns, so the short-exposure images were recorded by a high speed video camera and the results show that the dim spot resulting from the volume discharge and surface discharge co-exist in the rhombus patternⅡ. Further study of the electron densities of bright spot of three kinds of patterns found that the hightest was the prepattern of the rhombus patternⅡ and the lowest was the rhombus patternⅡ. These results are of great importance to the formation of the patterns in dielectric barrier discharge.