| The emission spectroscopy and laser-induced fluorescence techniques have been used to diagnose the OH etc. active species produced by pulsed corona discharge at atmospheric pressure and OH radicals produced by DC glow discharge at low pressure respectively. The main results presented in the dissertation have been summarized as follows:1.The emission spectra of N2(C3Πu→B3Πg), OH (A2∑→X2Π0-0), O(3p5P→3s5S20), H (n=3-2), and N (3p4S0→3s4P) produced by the high-voltage positive, negative, and bi-directional pulsed corona discharge of N2+H2O mixture gas with a needle-plate electrode configuration have been successfully recorded against a severe electromagnetic interference at one atmosphere. The effects of pulsed peak voltage, pulsed repetition rate, and the added O2 flow rate on the emission intensities of OH(A2∑→X2Π0-0), O(3p5P→3s5S20), H (n=3-2), and N (3p4S0→3s4P) and the relative populations of OH (A2∑) radicals and O (3p5P), N (3p4S0) active atoms are also investigated. It is found that when the pulsed peak voltage and the pulsed repetition rate are increased, the emission intensities of OH (A2∑→X2Π0-0), O(3p5P→3s5S20), H (n=3-2), and N (3p4S0→3s4P) and the relative populations of OH(A2∑) radicals and O(3p5P), N (3p4S0) active atoms enhance correspondingly. The emission intensities of O(3p5P→3s5S20), H(n=3-2), and N (3p4S0→3s4P) and the relative populations of O(3p5P), N (3p4S0) active atoms increase with the flow rate of oxygen (from 0 to 30 mL/min) and achieve a maximum value at flow rate of 30 mL/min. When the flow rate of oxygen is increased further, the emission intensities of O(3p5P→3s5S20), H(n=3-2), and N (3p4S0→3s4P) and the relative populations of O(3p5P), N (3p4S0) active atoms decrease obviously. The emission intensity of OH (A2∑→X2Π0-0) and the relative population of OH (A2∑) radicals decrease with increasing the added oxygen.2. The emission spectrum of N2(C3Πu→B3Πg) produced by the high-voltage positive pulsed corona discharge of N2 and the emission spectra OH (A2∑→X2Π0-0) and N2 (B2∑u+→X2∑g+ 0-0) produced by the high-voltage positive pulsed corona discharge of N2+H2O mixture gas in a wire-plate electrode configuration have been recorded. The effects of the pulsed peak voltage, the pulsed repetition rate, and the added O2 flow rate on the spatially resolved distributions of the emission intensities of N2(C3Πu→B3Πg) produced by the high-voltage positive pulsed corona discharge of N2 are investigated. The spatially resolved distributions of the emission intensities of N2(C3Πu→B3Πg) produced by the high-voltage positive pulsed corona discharge of N2, air, and N2+O2 at a fixed discharge parameter are also studied. It is found that the emission intensity of N2(C3Πu→B3Πg) decreases with increasing the distance from the wire electrode nonlinearly at fixed pulsed peak voltage and pulsed repetition rate. The normalized spatially resolved emission distribution is similarly at different pulsed peak voltage and pulsed repetition rate. The normalized spatially resolved emission distribution is also similarly in N2, air, and N2+O2 at fixed pulsed peak voltage and pulsed repetition rate.OH(A2∑→X2Π0-0) and N2+(B2∑u+→X2∑u+ 0-0) and the vibrational temperature of N2 (C) produced by the high-voltage positive pulsed corona discharge of N2+H2O mixture gas in a wire-plate electrode configuration have been studied. The emission intensities of OH (A2∑→X2Π0-0) and N2+(B2∑u+→X2∑u+ 0-0) increase with increasing the pulsed peak voltage and the pulsed repetition rate and decrease with increasing the added oxygen. The emission intensity of OH (A2∑→X2Π0-0) decreases with increasing the distance from the wire electrode. The emission intensity of N2+ (B2∑u+→X2∑u+ 0-0) is nearly constant with increasing the distance from the wire electrode 0-3 mm, but sharply increases near the plate electrode 1-3 mm. The vibrational temperature of N2(C) is nearly keep constant in the lengthwise direction when increasing the pulsed peak voltage and pulsed repetition rate, but increases with increasing the added oxygen.The spatially resolved measurements of the emission intensity of OH(A2∑→X2Π0-0) and the vibrational temperature of N2 (C) in N2+He, N2+Ar and N2+O2 mixture gases are also measured. It is found the emission intensity of OH (A2∑→X2Π0-0) decreases with increasing the distance from the wire electrode and increases a little near the plate electrode. The emission intensity of OH (A2∑→X2Π0-0) increases with increasing the proportions of He in N2+He mixture gas and Ar in N2+Ar mixture gas, and decreases with increasing the proportion of O2 in N2+O2 mixture gas. The vibrational temperature of N2(C) is nearly keep constant in the lengthwise direction, and increases with increasing the proportions of He in N2+He mixture gas and O2 in N2+O2 mixture gas, but decreases with increasing the proportions of Ar in N2+Ar mixture gas.3. The fluorescence spectrum of OH (A2∑→X2Π0-0) produced by a needle-plate negative DC discharge are investigated with a laser-induced fluorescence system in water vapor, N2+H2O mixture gas, He+H2O mixture gas. The effects of discharge voltage and pressure on the fluorescence intensity of Q1(1) line is investigated. It is found that the fluorescence intensity of Q1(1) line nearly keep constant with increasing the applied voltage and decreases with increasing pressure in pure water vapor. The fluorescence intensity of Q1(1) line increases with increasing the applied voltage and decreases with increasing pressure in N2+H2O mixture gas. The fluorescence intensity of Q1(1) line nearly keep constant with increasing the applied voltage and exhibits a maximum value under the investigated pressure range in He+H2O mixture gas.
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