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By optical emission spectrum, we report on the first investigation on the spectral characteristics of filaments in three layers gas gap in dielectric barrier discharge, which filled with gas-mixture of argon and air. The filaments are generated in 1 mm gas gap, 4 mm gas gap and 2 mm gas gap, respectively. With previous single layers gas gap or double layers gas gap of the filaments are very different in terms of spectral characteristics. The emission spectra of the N2 second positive band (C(3)Π(u)→B(3)Π(g))are measured, from which the molecule vibrational temperature of the filaments which generated in different gas gap are calculated. Based on the relative intensity of the line at 391.4 nm and the N2 line at 394.1 nm, the electron average energy of the filaments which generated in different gas gap are investigated. Increasing the content of argon, the change of the molecule vibrational temperature and the electron average energy of the filaments are investigated. It is found the ascending order of the molecule vibrational temperature in the same argon content is: 2 mm gas gap, 1 mm gas gap and 4 mm gas gap. However the ascending order of the electron average energy in the same argon content is: 4 mm gas gap, 2 mm gas gap and 1 mm gas gap. The molecule vibrational temperature and the electron average energy of the filaments decrease with the argon content increasing.

A novel plasma jet driven by an alternating current voltage is developed to generate atmospheric pressure non-equilibrium plasma plumes in the downstream region and in the upstream one of the argon flow. The angle between the rod electrode and the gas flow can be changed easily, and the plume lengths in the downstream and upstream regions are investigated as a function of the angle and the peak voltage. With increasing the peak voltage, the discharge pulse number tends to increase for every half voltage cycle. Using an intensified charge-coupled device camera, the dynamics of the plasma plumes is also investigated in the downstream and upstream regions. The dynamics of the plumes is qualitatively explained by the streamer propagations influenced by residual charges.

The spot-halo hexagon pattern consisted of the center spot and hexagon halo in dielectric barrier discharge is researched, which filled with gas-mixture of argon and air. The pictures taken from the experiment shows that there is an obvious difference on brightness between the center spot and hexagon halo. All of these phenomena suggest that the center spot and hexagon halo are probably in different plasma state. The plasma parameters of the center spot and hexagon halo in the spot-halo hexagon pattern as a function of gas pressure are studied in details by using optical emission spectra. The emission spectra of the N2 second positive band(C3Πu→B3Πg)are measured, from which the molecule vibrational temperature of the center spot and hexagon halo are calculated. Based on the relative intensity of the line at 391.4 nm and the N2 line at 394.1 nm, the change of the electron average energy of the center spot and hexagon halo as a function of gas pressure is investigated. The electron density is studied by using the broadening of the spectral line 696.5 nm. It is found that the main chart of the spot-halo hexagon pattern is the argon content from 60% to 75% and the pressure from 30 to 46 kPa. The molecule vibrational temperature and electron average energy of the hexagon halo are higher than those of the center spot at the same pressure. As the pressure gradually increased from 30 to 46 kPa, the molecule vibrational temperature and electron average energy of the center spot and hexagon halo are increased, too. The broadening of the spectral line of the hexagon halo is bigger than the center spot at the same pressure, which increases with the gas pressure increasing. It indicates that the electron density increases with gas pressure increasing. The different plasma state of the center spot and hexagon halo show that the different formations mechanism of them. It is found that there are volume discharges firstly and then comes surface discharges with e high speed camera.

The front dynamics driven by a convection field in a model of FitzHugh—Nagumo type is studied both analytically and numerically. Saddle-node bifurcation induced by the convection field is found by using a singular perturbation analysis of front solutions. Convection field accelerates the Bloch front propagating opposite the direction of convection field, but inhibits the Bloch front propagating along the direction of convection field. In addition convection field drives Ising front to travel opposite the direction of convection field.

Square super-lattice pattern with surface discharge consisting of central spots and dim spots is firstly observed in the mixture of argon and air by using a dielectric barrier discharge device with water electrodes. By observing the image, it is found that the central spot is located at the centriod of its surrounding four dim spots. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The brightness of the central spot and is quite different from that of the dim spot, which indicates that the plasma states of the central spot and the dim spot may be differentiated. The optical emission spectrum method is used to further study the several plasma parameters of the central spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --B³ IIg) are measured, from which the molecule vibration temperatures of the central spot and the dim spot are calculated respectively. The broadening of spectral line 696.57 nm (2P₂--1S₅) is used to study the electron densities of the central spot and the dim spot. It is found that the molecule vibration temperature and electron density of the dim spot are higher than those of the central spot in the same argon content The molecule vibration temperature and electron density of the central spot and the dim spot increase with the argon content increasing from 90% to 99.9%. The surface discharge induced by the volume discharge (VD) has the determinative effect on the formation of the dim spot The experimental results above play an important role in studying the formation mechanism of surface dischargof square super-lattice pattern with surface discharge. In addition, the studies exert an influence on the application of surface discharge and volume discharge in different fields.

The hexagonal super-lattice pattern composed of the light spot and the dim spot is firstly observed and investigated in the discharge of gas mixture of air and argon by using the dielectric barrier discharge device with double water electrodes. It is found that the dim spot is located at the center of its surrounding three light spots by observing the discharge image. Obviously, the brightness of the light spot and the dim spot are different, which indicates that the plasma states of the light spot and the dim spot may be different. The optical emission spectrum method is used to further study the several plasma parameters of the light spot and the dim spot in different argon content. The emission spectra of the N₂ second positive band (C³IIu --B³IIg) are measured, from which the molecule vibration temperatures of the light spot and the dim spot are calculated. Based on the relative intensity ratio of the line at 391.4 nm and the N₂ line at 394.1 nm, the average electron energies of the light spot and the dim spot are investigated. The broadening of spectral line 696.57 nm (2P₂-1S₅) is used to study the electron densities of the light spot and the dim spot. The experiment shows that the molecule vibration temperature, average electron energy and the electron density of the dim spot are higher than those of the light spot in the same argon content. The molecule vibration temperature and electron density of the light spot and dim spot increase with the argon content increasing from 70% to 95%, while average electron energies of the light spot and dim spot decrease gradually. The short-exposure image recorded by a high speed video camera shows that the dim spot results from the surface discharges (SDs). The surface discharge induced by the volume discharge (VD) has the decisive effect on the formation of the dim spot. The experiment above plays an important role in studying the formation mechanism of the hexagonal super-lattice pattern with light spot and dim spot. In addition, the studies exert influences on the application of surface discharge and volume discharge in different fields.

By optical emission spectrum, we report on the first investigation on the plasma parameters of micro plasma channels which are generated in two gas-gaps with different thickness in a triple-layer dielectric barrier discharge system. Different from the micro plasma channels formed in traditional two-layer dielectric barrier discharge, micro plasma channels formed in the triple-layer dielectric barrier discharge system reflect a unique discharge characteristic. From the pattern images taken by an ordinary camera, it shows that micro plasma channels generated in two discharge gas-gaps discharge with different sizes and light intensities. The micro plasma channels in wide gas-gap are much bigger than those in narrow gas-gap, and their light intensities are obvious stronger. By collecting the emission spectra of N2 second positive band (C3∏u --B3∏g ) and calculating the relative intensity ratio method of N2 molecular ion line at 391.4 and the N2 molecular line at 394.1, the molecular vibration temperature and the average electron energy of micro plasma channels in two gas-gaps as functions of Argon concentration and applied voltage are investigated, respectively. It is found that the molecular vibration temperature and the average electron energy of micro plasma channels in wide gas-gap are lower than those in narrow gas-gap, and they both decrease with the increasing of the Argon concentration. As the applied voltage increases, micro plasma channels in wide gas-gap vary in a small range on the above two plasma investigations, while those in narrow gas-gap vary obviously. It indicates that micro plasma channels in narrow gas-gap are more sensitive to the applied voltage and they have a wider variation range of electric field than those in wide gas-gap.

The white-eye pattern was firstly observed and investigated in a dielectric barrier discharge system in the mixture of argon and air whose content can be varied whenever necessary, and the study shows that the white-eye cell is an interleaving of three different hexagonal sub-structures: the center spot, the halo, and the ambient spots. The white-eye pattern is observed at a lower applied voltage. In this experiment, the heat capacity of water is high so that the water in water electrode is good at absorbing heat. In the process of pattern discharging the gas gap didn't increase its temperature, and the discharging phenomenon of this pattern has not changed. The temperature of the water electrodes almost keeps unchanged during the whole experiment, which is advantageous for the long-term stable measurement. Pictures recorded by ordinary camera with long exposure time in the same argon content condition show that the center spot, the halo, and the ambient spots og the white-eye pattern have different brightness, which may prove that their plasma states are different. And, it is worth noting that there are obvious differences of brightness not only on the center spot, the halo, and the ambient spots at the same pressure but also at the different pressure, which shows that its plasma state also changed with the variation of the pressure. Given this, in this experiment plasma temperatures of the central spot, halo, and ambient spots in a white-eye pattern at different gas pressure were studied by using optical emission spectra. The molecular vibration temperature is investigated by the emission spectra of nitrogen band of second positive system ( C3Πu --B3Πg ). The electron excitation temperature is researched by the relative intensity ratio method of spectral lines of Ar I 763. 51 nm (2P6 --1S5) and Ar I 772. 42 nm (2P2 --1S3). The electronic density is investigated by the broadening of spectral line 696.5 nm. Through the analysis of experimental results, it is found that the molecular vibration temperature, electron excitation temperature and electronic density of the central spot are lowest, and the plasma parameters of the ambient spots are second, while the plasma parameters of the halo are highest at the same condition. The molecular vibration temperature and the electron excitation temperature of the three different parts of the pattern (central spot, halo, and ambient spots) decrease with the pressure increasing from 40 to 60 kPa, but the electronic density increases. These results are of great important to the formation mechanism of the patterns in dielectric barrier discharge.

The single filament (also referred to as monofilament) which composed of two parts including the center spot and the outer halo is observed and researched for the first time in dielectric barrier discharge, which filled with gas-mixture of argon and air. The pictures taken from the experiment show that the diameter of the monofilament decreases with the increasing of the content of the argon in the argon-air mixture, and at the same time there is an obvious difference on brightness between the center spot and the outer halo. All of these phenomenons suggest that the center spot and the outer halo are probably in different plasma state. The micro character of the center spot and the outer halo is researched seriously in the experiment by the time-resolved measurement with optical method. Three plasma temperatures of the center spot and the outer halo in single filament in different argon content are studied in details by using optical emission spectra. The emission spectra of the N2 second positive band (C3 π(u) --B3 πg) are measured, from which the molecule vibrational temperature of the center spot and the outer halo are calculated. Based on the relative intensity of the N2 line at 391.4 nm and the N2 line at 394. 1 nm, the changing relationship of the average electron energy of the center spot and the outer halo with argon content is investigated. The spectral lines of Ar I 763.2 nm (2P6 --1S5) and 772.077 nm (2P2 --1S3) are chosen to estimate electron excitation temperature of the center spot and the outer halo by the relative intensity ratio method. The results show that the optical signal corresponding to the first lasge pulse is the center spot, whose signal intensity is a litter weaker; and the optical signal containing the whole pulse is the outer halo, whose signal intensity is stronger. The three plasma temperatures including the molecule vibrational temperature, average electron energy and electron excitation temperature of the outer halo are higher than those of the spot at the same argon content without exception. In addition, the molecule vibrational temperature of the center spot and the outer halo decrease with the argon content increases from 30% to 50%, while on the other hand, electron excitation temperature and average electron energy are decrease gradually.

By using the water-electrode discharge experimental setup, the white-eye hexagonal pattern is firstly observed and investigated in the dielectric barrier discharge with the mixture of argon and air whose content can be varied whenever necessary, and the study shows that the white-eye cell is an interleaving of three different hexagonal sub-structures: the spot, the ring, and the halo. The white-eye hexagonal pattern has the excellent discharge stability and sustainability during the experiment. Pictures recorded by ordinary camera with long exposure time in the same argon content condition show that the spot, the ring, and the halo of the white-eye hexagonal pattern have different brightness, which may prove that their plasma states are different. And, it is worth noting that there are obvious differences not only on the brightness but also on the color of the white-eye cell in conditions of different argon content, which shows that its plasma state also changed with the variation of the argon content. The white-eye hexagonal pattern is observed at a lower applied voltage so that the temperature of the water electrodes almost keeps unchanged during the whole experiment, which is advantageous for the long term stable measurement. The plasma state will not be affected by the temperature of the electrodes during the continuous discharge. Based on the above phenomena, plasma temperatures of the spot, the ring, and the halo in white-eye hexagonal pattern including molecule vibrational temperature and variations of electron density at different argon content are investigated by means of optical emission spectroscopy (OES). The emission spectra of the N2 second positive band(C3Πu--B3Πg)are measured, and the molecule vibrational temperature of the spot, the ring, and the halo of the white-eye hexagonal pattern are calculated by the emission intensities. Furthermore, emission spectra of Ar I (2P2--1S5)is collected and the changes of its width with different argon content are used to estimate the variations of electron density of the spot, the ring, and the halo of the white-eye hexagonal pattern. In the same argon content condition, the molecule vibrational temperatures of halo, ring, and spot in the white-eye hexagonal pattern are in descending order, while the electron densities of halo, ring, and spot are in ascending order. With argon content increasing from 70% to 90%, both the molecule vibrational temperature and the electron density of the spot increase, while both of them of the halo decrease. And the molecule vibrational temperature of the ring keeps constant, while its electron density decreases. The experimental results indicate that the plasma state of the spot, the halo and the ring in a white-eye cell of the white-eye hexagonal pattern is different. These results are of great importance to the investigation of the multilayer structure of the patterns in dielectric barrier discharge and applications in industry.

A new type of single filament was observed in a dielectric barrier discharge (DBD) system for the first time. It was formed with a larger discharge gap (d=3. 8 mm) and a smaller discharge area (S= 1 cm x 1 cm) in an air/argon gas mixture. Compared with the single filament observed by other experimental groups, the new type of single filament is composed of volume discharge (VD) and surface discharge (SD). In addition, the single filament has excellent discharge stability and sustainability. In order to study more about the discharge characteristic of the new type of single filament in a half-cycle of the applied voltage and the plasma state in different positions of the discharge column in the side view of the new type of single filament, both a high speed framing camera (HSFC) and a spectrograph were used in the experiment. The instantaneous images of end and side view of the new type of single filament were taken by the HSFC with different exposure time, and the discharge characteristic of the new type of single filament in a half-cycle of the applied voltage was compared with that of glow discharge. The spectral lines of Ar I 763. 26 nm (2P6--1S5) and Ar I 772.13 nm (2P2--IS3) in different positions of the discharge column of the new type of single filament were measured by using optical emission spectra, and chosen to estimate the corresponding electron excitation temperature by the relative intensity ratio method. It was found that the new type of single filament is composed of VD and SD, and SD produces a dendritic discharge around VD. The discharge characteristic of the new type of single filament in a half-cycle of the applied voltage is similar to that of glow discharge, and a funnel-shaped discharge emerges at the instantaneous cathode. The spectral line intensity and the corresponding electron excitation temperature all decrease with the distance away from the electrodes, indicating that the plasma state in different positions of the discharge column in the side view of the new type of single filament is different.

A modified U-tube conical bubble sonoluminescence device is used to study the conical bubble photoluminescence. The spectra of conical bubble sonoluminescence at different concentrations of rhodamine 6G (Rh6G) solution in 1,2-propanediol have been measured. Results show that the sonoluminescence from the conical bubbles can directly excite Rh6G, which in turn can fluoresce. The light emission of this kind is referred to as conical bubble photoluminescence. The maximum of fluorescence spectral line intensity in the conical bubble photoluminescence has a red shift in relative to that of the standard photo-excited fluorescence, which is due to the higher self-absorption of Rh6G, and the spectral line of conical bubble photoluminescence is broadened in width compared with that of photo-excited fluorescence.

Two kinds of square patterns with different spatiotemporal symmetry were observed in dielectric barrier discharge, and their plasma parameters were measured by using optical emission spectra. It was found that the spatiotemporal symmetry of the square pattern at lower gas pressure is different from the one at higher gas pressure. Six spectral lines in the emission spectrum of the N2 second positive band were chosen to estimate the vibrational temperature, and the ratio of I391.4/I394.1 was used to represent the average electron energy. The excitation temperature was determined by the ratio of I763.2/I772.1. Furthermore, the width and shift of Ar I 696.54 nm were used to estimate the electron density. The results show that the vibrational temperature, excitation temperature and electron energy of the square pattern at lower gas pressure are higher than those at higher gas pressure, while the electron density is lower than that at higher gas pressure.

The authors report on the first investigation of the variations in the plasma parameters in the formation process of the honeycomb pattern in a dielectric barrier discharge by optical emission spectrum in argon and air mixture. The discharge undergoes hexagonal lattice, concentric spot-ring pattern and honeycomb pattern with the applied voltage increasing. The molecular vibration temperature, electron excitation temperature and electronic density of the three kinds of patterns were investigated by the emission spectra of nitrogen band of second positive system (C3pi(u) --B3 pi(g)), the relative intensity ratio method of spectral lines of Ar I 763.51 nm (2P(6) --1S(5)) and Ar I 772.42 nm (2P(2) --1S(3)) and the broadening of spectral line 696.5 nm respectively. It was found that the molecular vibration temperature and electron excitation temperature of the honeycomb pattern are higher than those of the hexagonal lattice, but the electron density of the former is lower than that of the latter. The discharge powers of the patterns were also measured with the capacitance method. The discharge power of the honeycomb pattern is much higher than that of the hexagonal lattice. These results are of great importance to the formation mechanism of the patterns in dielectric barrier discharge.

A large area surface discharge was realized in air/argon gas mixture by designing a discharge device with water electrodes. By using optical emission spectrum, the variations of the molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature as a function of the gas pressure were studied. The nitrogen molecular vibrational temperature was calculated according to the emission line of the second positive band system of the nitrogen molecule (C3 pi(u) --B 3 pi(g)). The electronic excitation temperature was obtained by using the intensity ratio of Ar I 763.51 nm (2P(6) --1S(5)) to Ar I 772.42 nm (2P(2) --1S(3)). The changes in the mean energy of electron were studied by the relative intensity ratio of the nitrogen molecular ion 391.4 nm to nitrogen 337.1 nm. It was found that the intensity of emission spectral line increases with the increase in the gas pressure, meanwhile, the outline and the ratios of different spectral lines intensity also change. The molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature decrease as the gas pressure increases from 0.75 x 10(5) Pa to 1 x 10(5) Pa.

The volume discharge (VD) and surface discharge (SD) were observed in dielectric barrier discharge with a relatively large discharge gap simultaneously by using a high-speed camera. The variations of the spectral line profiles of VD and SD as a function of the discharge parameters were studied by using optical emission spectra. The changes in the width and shift of Ar I (2P2--1S5) spectral lines of VD and SD with gas pressure and discharge gap were measured in dielectric barrier discharge in argon. It was found that both the width and shift of SD are bigger than those of VD, indicating that the electron density of SD is higher than that of VD. The width and shift of VD and SD increase with the gas pressure increasing, indicating that the electron density of VD and SD increases with the gas pressure increasing. The width of VD and SD increases with the gas gap d increasing from 3. 8 to 4. 4 mm, reflecting that the electron density of VD and SD increases with d increasing.

The characteristics of striations in cylindrical hollow cathode discharge were investigated experimentally. The spectra of striations were measured at a pressure of 20 Pa in a discharge of 1.3 mA, in which the main spectra are the emission spectrum lines of the N2 first positive band (B3pi(g)--A3pi(u)) and second positive band system (C3pi(u)--B3pi(g)). The spatial characteristics of vibrational temperature of N2 were calculated based on the theory of double molecular spectrum. It is shown that the emission intensity exhibits a periodic structure with an unequal magnitude, and the spectral intensity of bright striation is higher than that of dark striations. The vibrational temperature of bright striation is of the value of 3500-4400K, moreover the vibrational temperature in the bright regions decreases from the cathode to the anode. In addition, the characteristics of striations at 1.0 mA and 1.5 mA were obtained, and the influence of discharge current on the striations was investigated. It is shown that the vibrational temperature and the distance between two striations increase. Finally the reduced electric field was calculated, which is about 44 approximately 49 m(-1) x Pa(-1), moreover it decreases with the increase in discharge current. The results are very useful for understanding the mechanism of discharge striations and for improving the stability of hollow cathode discharge.

The effect of plasma parameters and excited states on the stable process of the hexagon pattern in a dielectric barrier discharge was studied by using optical emission spectra. It was found that the diameter of the discharge filament increases, the pattern gets more stable, and the color of the pattern changes from purple to gray with the increase in the voltage in dielectric barrier discharge in argon and air mixture. It indicates that the plasma excited states and parameters may be changed. To this end, the relative intensity of N2 and Ar spectral lines with respect to Ar I 763.51 nm, the molecular vibration temperature, and the electron excitation temperature were measured with the change in the applied voltage. The results show that the relative intensity of N2 spectral lines decreases and that of Ar spectral lines increases with the increase in the voltage. And both the molecular vibration temperature and the electron excitation temperature increase. These phenomena indicate that the electron energy increases with the increase in the voltage. The increase of the stimulated argon atoms excited by higher energy electron leads to the increase in the diameters of the discharge filaments. Correspondingly, the areas of the wall charges deposited on the dielectric increase, which results in the enhancement of the interactions between filaments, and therefore the hexagon pattern becomes stable.

Octagon structure consisting of the spots and lines was firstly observed in discharge in argon and air mixture by using a dielectric barrier discharge device with water electrodes. Plasma temperatures of the spots and lines in octagon structure at different gas pressure were studied by using optical emission spectra. The emission spectra of the N2 second positive band (C3IIu--B3IIg)were measured, and the molecule vibrational temperatures of the spots and lines were calculated by the emission intensities. Based on the relative intensity of the line at 391.4 nm and the N2 line at 394.1 nm, the average electron energy of the spots and lines were investigated. The spectral lines of Ar I 763.26 nm ((2)P6-1Ss) and 772.13 nm ((2)P2--1S3) were chosen to estimate electron excitation temperature of the spots and lines by the relative intensity ratio method. The molecule vibrational temperature, average electron energy, and electron excitation temperature of the lines are higher than those of the spots at the same pressure. The molecule vibrational temperature, average electron energy, and electron excitation temperature of the spots and lines decrease with pressure increasing from 40 to 60 kPa.

The emission spectrum line shift and vibrational temperature of dot and line discharges, which coexist in argon/air dielectric barrier discharge, were measured and compared. Emission spectral lines of ArI (2P2 --1S5) and the N2 second positive band system (C 3pi(u) --B 3pi(g)) were used to measure the spectrum line shift and the vibrational temperature respectively. It was found that the spectrum line shift of the dot discharge channel is larger than that of the line discharge channel, indicating that the former has high electron density compared to the latter. While the vibrational temperature of the dot discharge channel is lower than that of the line discharge channel.

The white-eye pattern, whose cell is composed of a bright dot surrounded by a closed hexagon, was observed in air/ argon dielectric barrier discharge. It was found that the center dot, the vertex of hexagon and the center of hexagon side in a cell have different brightness. By using optical emission spectra, the vibrational temperature in the center dot, the vertex of hexagon and the center of hexagon side was measured, respectively. The variations in the vibrational temperature at these three places as a function of the content of argon in gas mixture were also studied. The vibrational temperature was calculated by emission spectral lines of the N2 second positive band system (C3IIu --B3IIg). The experimental results show that the vibrational temperature of the center dot, the vertex of hexagon and the center of hexagon side is in the ascending order and decreases with the increase in the content of argon in gas mixture.

The cluster hexagon pattern was obtained in a dielectric barrier discharge in air/argon for the first time. Three plasma parameters, i. e. the molecular vibrational temperature, the molecular rotational temperature and the average electron energy of individual cluster in cluster hexagon pattern discharge, were studied by changing the air content. The molecular vibrational temperature and the molecular rotational temperature were calculated using the second positive band system of nitrogen molecules (C 3IIu --B 3IIg) and the first negative band system of nitrogen molecular ions (B 2Sigma(u)+ --Chi2 Sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391. 4 nm) and nitrogen molecules emission spectrum line (337.1 nm) were analyzed for studying the variations of the electron energy. It was found that the three plasma parameters of individual cluster in cluster hexagon pattern increase with air content increasing from 16% to 24%.

The emission spectrum line shift and vibrational temperature of the bright dot and dark dot discharges, which are observed in the argon and air dielectric barrier discharge at high temperature for the first time were measured and compared. The line shift of the spectral line of the Ar I (2P2--1S5) is measured and the vibrational temperature was calculated using by the emission spectral lines of the N2 second positive band system (C3Pi(u)--B3Pi(g)). The results show that the spectrum line shift of the bright dot discharge channel is larger than that of the dark dot channel, which indicates that the former has higher electron density compared to the latter, and the vibrational temperature of the dark dot discharge channel is higher than that of the bright dot discharge channel.

The diffuse discharge plasma in air was observed in a dielectric barrier discharge with two semispherical water electrodes. The variations of vibration temperature, rotation temperature, and average electron energy as the function of the applied voltage were studied by emission spectroscopy. The vibration temperature and the rotation temperature were calculated through the second positive band system (C3Pi(u)--B3Pi(g)) of N2+ and the first negative band system (B2 Sigma(u+)--Chi2Sigma(g+)) of N(2+) respectively. The average electron energy was studied by intensity ratio of 391.4 and 337.1 nm. It was found that the rotation temperature increases with the applied voltage increasing, while the vibration temperature and the electron energy decrease.

To evaluate the protective rate and the variation of HFRS-IgG on hemorrhagical fever with renal syndrome (HFRS) vaccine.Cluster, random sampling and cross-sectional study were used to assess the protective rate of HFRS vaccination. Level of HFRS-IgG was detected with ELISA in epidemic and non-epidemic areas of HFRS.Curve equation was obtained as Yprotective rate=(0.863+0.283/Xvaccination term)×100% by protective rate with vaccination term. Protective rates showed a reducing trend, 90% after 7-8 years of vaccination, 88% after 10 years, and 94% on average. Absorbance (A) value of HFRS-IgG was 4 times higher in persons with vaccination than those without, in the epidemic area. Higher antibody level could be obtained after primary vaccination, but the level of antibody had a 50% reduction after 5-10 years of vaccination, and a 60% reduction after 10 years of vaccination.HFRS antibody had a 50% reduction after 5-10 years of vaccination. The protective rate of HFRS vaccination had a 90% loss, after 7-8 years of vaccination. Booster dose was necessary after 7 years of vaccination.

The variations of width and shifts of Ar I (2P2 --1S(5)) spectral line emitted from two types of filaments, whose diameters and states are different, in argon/air dielectric barrier discharge with the change in air content were researched for the first time. In order to measure the wavelength shift, Ar I (2P2 --1S(5)) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. Regular arrangements of static wide filaments (static big dots) and moving thin filaments (reciprocating moving small dots whose traces are lines) were obtained in discharge at atmospheric pressure when the air content was in the range of 0.4%-4%. The variations of width and shifts of Ar I (2P2 --1S(5)) spectral line emitted from the big and small dots with the change in air content were measured respectively. It was found that they all increase with the increasing in air content. The width and shift of small dot are bigger than those of the big dot at any air content. The difference between the former and the latter decreases with the increase in air content firstly and remains basically unchanged after the air content reaches up to 1%.

In the present work, the spatial distributions of spectrum intensity of molecule and atom in the plasma generated in hollowneedle-plate discharge in atmosphere were measured, and the spatial distribution of electron energy in plasma was analyzed. A plasma about 3 cm long is generated by using a hollowneedle-plate discharge device. By collecting optical emission spectrum from 300 to 800 nm, it was found that the spectrum consists of strong Ar I lines, strong second positive band system of N2, and weak OI line. The spatial distributions of spectrum intensity of Ar I (696.54, 763.51, 772.42, and 794.82 nm), band N2 (337.1, 357.6, and 380.4 nm), and OI 777.2 nm were measured. The Ar I lines decreased gradually from the arc root. The N2 lines increased gradually from the arc root and declined when they reached a maximum at 12 mm away from the arc root. The intensity of OI increased from the arc root and declined when it reached a maximum at 6 mm away from the arc root. The spatial distribution of electron energy in plasma was analyzed qualitatively from the spatial distribution of spectrum intensity given above. It was found that the electrons located at 6 mm away from the are root have high energy, while they have low energy at arc tip.

Vibrational temperature in circle discharge channel and central dot discharge channel of circle-dot filament in argon/air dielectric barrier discharge was firstly measured by using optical emission spectra. The variations of the vibrational temperature in central-dot discharge channel and circle discharge channel as a function of air content were also studied. Emission spectral lines of the N2 second positive band system (C 3pi(u) --B 3pi(g)) were used to calculate the vabrational temperature. It was found that the vibrational temperature of circle is higher than that of the central dot. The vibrational temperature of circle increases more rapidly than that of central dot although both increase with the increase in air content. These results are of great importance to the study of microdischarge in dielectric barrier discharge system.

Different discharge modes in different boundary discharge domains at the same experimental condition are observed in argon/air mixture in a dielectric barrier discharge system with two large diameter water electrodes. Regular patterns and random filaments are formed in the closed square boundary and the semiopen domain respectively. It is found that the relatively intensity of the several higher excitation energy spectral lines such as 696.5, 727.3, 750.4 and 772.4 nm increases with the applied voltage in the closed boundary domain while decreases in the semiopen domain. Results show that the electron average energy in the closed boundary is higher than that in the semiopen domain and the difference of the electron average energy increases with the applied voltage. The results of molecular vibration temperature estimated by the second positive spectrum of N2 molecular indicate that the vibration temperature increases with the applied voltage in the closed boundary and decreases with the applied voltage in the semiopen boundary domain.

The variations of width and shift of Ar I (2P2 --1S5) spectral line with discharge parameters were studied in a slot microplasma. In order to measure the wavelength shift, the Ar I (2P2 --1S5) spectral line emitted from argon discharge at pressure of 10 Pa was used as a reference line. With the gas pressure increasing in the range of 1 x 10(4) - 6 x 10(4) Pa, the width and shift of Ar I (2P2 --1S5) spectral line were measured in argon (99.92%)/air discharge. It was found that both the width and the shift of Ar I (2P2 --1S5) spectral line increase linearly with the increase in gas pressure, indicating that the electron density increases with the increase in gas pressure. In addition, the width and the shift of Ar I (2P2 --1S5) spectral line at gas gap width of 100 and 300 microm were measured for comparison. It was found that both increase with the increase in gas gap width, which indicates that the electron density in the slot microplasma increases with the increase in gas gap width.

In the present work, a uniform discharge in low-pressure air was obtained by a dielectric barrier discharge device. The spatial homogeneity of the plasma temperature was studied by optical emission spectrum. The vibrational temperature was calculated by second positive band C3 pi(u) --B3 pi(g) and the rotational temperature (gas temperature) was calculated by N2+ first negative band B 2 sigma(u)+ --X 2 sigma(g)+. It was found that the vibrational temperature decreases with the voltage increasing, while the rotational temperature increases. In addition, the fluctuation amplitudes of vibrational and rotational temperature of the plasma along diameter of the discharge area decrease with the voltage increasing, which indicates that the homogeneity of the plasma increases with the voltage increasing. These results are of great significance to the application of uniform discharge obtained in air dielectric barrier discharge for material processing.

Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

A 1.6-3 cm long plasma torch was generated when argon gas was introduced by using a hollowneedle-plate discharge device working in atmosphere. The vibrational temperature and the gas temperature at plasma root and tip were studied by using optical emission spectrum at different argon gas flow. The gas temperature was obtained by comparing experimental line shape of OH radicals band around 309 nm with its simulated line shape. The vibrational temperature was calculated using N2 second posi tive band system C3:pi u-B3 pi g. It was found that the gas temperatures at arc root and arc tip are equal and they decrease with the argon flow rate increasing. The gas temperature decreases from 350 to 300 K when argon flow rate increases from 3.0 to 6.5 mL x min(-1). The vibrational temperature at are tip (1950 K) is higher than that at arc root (1755 K) under a low gas flow rate (e.g., 3.0 mL x min(-1)). With gas flow rate increasing, the vibrational temperature at both tip and root decreases, but the decreasing rate at are tip is faster than that at arc root. When gas flow is larger, the vibrational temperatures at tip and root tend to be equal.

In the present work, the spatial distributions of OH radicals and O atoms were studied in argon hollowneedle-plate discharge in ambient air. A 3 cm long plasma torch was generated in the discharge. The optical emission spectrum from 300 to 800 nm was collected. Besides Ar I lines and N2 second positive band system, OH emission band around 309 nm, O line at 777.4 nm and weaker H line were found in the optical emission spectrum. Because OH radicals and O atoms play an important role in material surface modification, the relative intensities of the OH radicals band (around 309 nm) and O atom line (777.4 nm) were analyzed. The results show that the number of OH radicals decreases rapidly and the number of O atoms follows a rule of increasing firstly and then decreasing from are root to arc tip.

The Stark broadening and Stark shift were described with different electric microfield distribution functions. These microfield distribution functions include Holtsmark, Neutral Point, Nearest-Neighbor and Mayer model microfield distribution function. The Stark profiles with four microfield distribution functions were studied and the Stark broadening and Stark shift were obtained from the Stark profiles to study the influence of different electric microfield distribution functions on Stark broadening and Stark shift. The results show that the influence of different electric microfield distribution functions on Stark broadening and Stark shift increases with the plasma ions impact parameter with the same electrons impact broadening parameter. With the increase in the plasma electrons impact parameter the influence of different electric microfield distribution functions increases with the same ion impact broadening parameter. Especially, the influence of Mayer model electric microfield distribution function is very distinct when the ion impact broadening parameter is larger. It is illuminated that the plasma ions intense impact has great influence on the spectral line profile. It is very important for the plasma diagnosis to select appropriate electric microfield distribution function. The results have important reference for the plasma diagnosis.

Based on the U-tube, a new type of sonoluminescence apparatus-conical bubble sonoluminescence straight tube apparatus was set up, and the structures and operations were described detailedly. Using the apparatus, the ultrabright cavitation luminescence was obtained in glycol solution. The light pulses of conical bubble sonoluminescence were detected, results show the half width is about 80 micros that is much longer than the results by ultrasound, which should be caused by the fact that the conical bubble can obtain more energy from the flow than the bubbles from the ultrasound. The spectra consist in a broad background ranging from the ultraviolet region to the visible region, on which five clear sequences of Swan bands and three sequences of B 2sigma+ --X 2sigma+ transition of CN are superimposed. A band assigned to the A 2delta --X 2II transition of CH was also measured. Specially, the vibrational structures of Swan bands can be resolved. Finally, the achieved molecular vibrational temperature of C2 is estimated to be about (4 200 +/- 200) K.

The energy transfer in dielectric barrier discharge in argon/air mixture in a device with water electrodes was investigated by comparing the optical emission spectra in pure argon, argon/air mixture and air. It was observed that the intensities of argon spectral lines in argon/air discharge are all lower than that in argon discharge, which indicates that the nitrogen in air has a quenching effect on the argon excited states. It was found that the decreasing rate of intensity of spectral lines with increasing the air concentration is different. The intensity of ArI 763. 51 nm decreases fastest, the ArI 772.42 nm and ArI 696.54 nm take second place, while the ArI 750.39 nm decreases slowest. Comparing the excitation energy of argon excited state with the excitation energy of nitrogen molecule, the authors found that the smaller the difference between the excitation energy of argon excited state and the excitation energy of nitrogen molecule, the faster the spectral line decreases, implying the stronger the energy transfer. In addition, the additional argon in air makes the emission intensities of nitrogen band of second positive system and band of first negative system increase, which indicates that the excitation of nitrogen is enhanced by the energy transfer from argon through Penning excitation involving argon metastable states. In other words, the component and ratio of gas in the gas mixture influence the optical characteristic and energy transfer peculiarity in the mixed gas discharge. The optical emission spectra measurement as a useful plasma diagnostic tool has been successfully used in the study of energy transfer in the mixed gas discharge, and the results provide a reasonable reference for the underlying industrial applications of different species discharge.

In the present paper, stable glow discharges were obtained in air at low pressure with a dielectric barrier surface discharge device. Light emission from the discharge was detected by photomultiplier tubes and the research results show that the light signal exhibited one discharge pulse per half cycle of the applied voltage. The light pulses were asymmetric between the positive half cycle and the negative one of the applied voltage. The images of the glow surface discharge were processed by Photoshop software and the results indicate that the emission intensity remained almost constant for different places with the same distance from the powered electrode, while the emission intensity decreased with the distance from the powered electrode increasing. In dielectric barrier discharge, net electric field is determined by the applied voltage and the wall charges accumulated on the dielectric layer during the discharge, and consequently, it is important to obtain information about the net electric field distribution. For this purpose, optical emission spectroscopy method was used. The distribution of the net electric field can be deduced from the intensity ratio of spectral line 391.4 nm emitted from the first negative system of N2+ (B 2sigma u+ --X 2sigma g+) to 337.1 nm emitted from the second positive system of N2 (C 3IIu-B 3IIg). The research results show that the electric field near the powered electric field is higher than at the edge of the discharge. These experimental results are very important for numerical study and industrial application of the surface discharge.

The electron energy in the transition from streamer discharge to glow-like discharge in dielectric barrier discharge in air was investigated by using emission spectra. The vibrational temperature was measured with the N2 second positive band (C3II(u) --B3II(g)) of the emission spectrum. The average electron energy was investigated from the relative intensity of the nitrogen molecular ion line at 391.4 nm and the nitrogen molecular line at 337.1 nm. It was found that the vibrational temperature and the relative intensity of nitrogen molecular ion line at 391.4 nm increased abruptly in the transition from streamer discharge to glow-like discharge. It was also found that the pressure for the transition pressure from streamer discharge to glow-like discharge changed with different gap distances, but the product of the transition pressure and gas gap width remained constant.