Chen Minggong

Electromagnetic interaction between local surface plasmon polaritons and an atmospheric surface wave plasma jet

We analyze the electromagnetic interaction between local surface plasmon polaritons (SPPs) and an atmospheric surface wave plasma jet (ASWPJ) in combination with our designed discharge device. Before discharge, the excitation of the SPPs and the spatial distribution of the enhanced electric field are analyzed. During discharge, the critical breakdown electric field of the gases at atmospheric gas pressure and the surface wave of the SPPs converted into electron plasma waves at resonant points are studied. After discharge, the ionization development process of the ASWPJ is simulated using a two-dimensional fluid model. Our results suggest that the local enhanced electric field of SPPs is merely the precondition of gas breakdown, and the key mechanism in maintaining the discharge development of a low-power ASWPJ is the wave-mode conversion of the local enhanced electric field at the resonant point.

A 30 mm Wide DC-Driven Brush-Shaped Cold Air Plasma Without Airflow Supplement

This paper reports a cold atmospheric pressure DC-driven air plasma brush. Three stainless steel needles are symmetrically mounted on a slot shaped PVC slab to act as the electrodes. The brush driven by a direct current (DC) power supply can generate an air plasma glow up to 30 mm wide with no inert gas addition and no air flow supplement. The plasma glow appears uniform no matter what kinds of material are processed. The measured current and the simulated current all show that each pulsed discharge including two peaks always occurs for different gaps between electrodes. Emission spectra measurement result shows that the obtained rotational temperatures are 300 K and the vibrational temperatures are 2250 K. Some reactive species are presented in the plasma glow, which suggest that the proposed plasma brush is beneficial to practical applications.

Pyrolysis of Ulva rigida by microwave heating

Pyrolysis of the macroseaweed Ulva rigida was conducted using microwave as eating source which is 2450Hz in frequency and 1kW in power. The gaseous, liquid and solid product was obtained and the gaseous product consists of CO2,CO,H2 and CH4, among which the first appears the earliest and the third appears at the later stage of pyrolysis with the irradiation time. The second component is absent or presents in trace amount, which might be due to the shift reaction spontaneously at the later stage of pyrolysis since hydrogen becomes predominant at this stage. The liquid yield is low, but it contains considerable organic components, including nitrogen containing substance.