The double-coupled microwave resonance probe(DMRP)based on the hairpin probe is proposed for diagnosing atmospheric plasma jet(ne<1017 m-3).In this work,the resonance characteristics of DMRP are investigated by numerical simulation.It shows that two resonance peaks on the reflectance spectrum can be observed,and influenced significantly by some parameters,such as the probe separation,the distance to the handheld radio frequency atmospheric pressure glow discharge plasma jet(RF-APGDPJ)and the plasma electron density less than 1017 m-3.Based on two resonance modes of DMRP,the electron densities in the afterglow of RF-APGDPJ at the different rf powers and helium flow rates are diagnosed experimentally by matching the change of FWHM(Df1-Df1,airand Df2-Df2,air)measured by vector network analyzer with the simulated relation between the FWHM changes and the plasma density.
A newly developed coaxial dielectric barrier discharge reactor with a length of1000 mm at an atmospheric pressure was used for plasma treatment of polyester fiber cord ina roll-to-roll manner. In this reactor, swirling mixture gases of oxygen of about 1% and argonwith a flow rate of 1.5 L/min to 2.7 L/min ensured the gas usage sparing, discharge uniformityand efficient fiber surface modification. The water contact angle and surface morphology of thetreated fiber were measured. The results show that the surface oxygenation is mainly responsiblefor the wettability improvement of the fiber cord when passing through the plasma zone at a linearspeed of 3 m/min to 8 m/min. The specimens of modified-polyester fiber reinforced rubber compositewere also prepared for the interfacial shear strength tests. Furthermore, the effect of addingoxygen into argon discharge on the fiber surface oxidation was correlated with optical emissionspectroscopy. Finally, the effect of adding oxygen into argon discharge on the kinetic processes ofthe active species generation were also analyzed.
