共查询到20条相似文献，搜索用时 15 毫秒
1.
This study investigates the influence of two types of target,skin tissue and cell culture medium,with different permittivities on a k Hz helium atmospheric pressure plasma jet (APPJ) during its application for wound healing.The basic optical–electrical characteristics,the initiation and propagation and the emission spectra of the He APPJ under different working conditions are explored.The experimental results show that,compared with a jet freely expanding in air,the diameter and intensity of the plasma plume outside the nozzle increase when it interacts with the pigskin and cell culture medium targets,and the mean velocity of the plasma bullet from the tube nozzle to a distance of 15 mm is also significantly increased.There are also multiple increases in the relative intensity of OH (A~2Σ?→?X~2Π) and O (3p~5S–3s~5S) at a position 15 mm away from nozzle when the He APPJ interacts with cell culture medium compared with the air and pigskin targets.Taking the surface charging of the low permittivity material capacitance and the strengthened electric field intensity into account,they make the various characteristics of He APPJ interacting with two different targets together. 相似文献
2.
The sterilizing effect of the non-equilibrium atmospheric pressure plasma jet by applying it to the Bacillus subtilis spores is invesigated. A stable glow discharge in argon or helium gas fed with active gas （oxygen）, was generated in the coaxial cylindrical reactor powered by the radio-frequency power supply at atmospheric pressure. The experimental results indicated that the efficiency of killing spores by making use of an Ar/O2 plasma jet was much better than with a He/O2 plasma jet. The decimal reduction value of Ar/O2 and He/O2 plasma jets under the same experimental conditions was 4.5 seconds and 125 seconds, respectively. It was found that there exists an optimum oxygen concentration for a certain input power, at which the sterilization efficiency reaches a maximum value. It is believed that the oxygen radicals are generated most efficiently under this optimum condition. 相似文献
3.
陈思乐;任鑫柳;陈兆权;徐笑娟;程涛;李平;张冠军;卢新培 《等离子体科学和技术》2023,25(11):115401-115401
Atmospheric fluorocarbon plasma plays an important role in the surface modification of insulating materials like polymers. The existing fluorocarbon plasma is usually generated by dielectric barrier discharge, which has a low concentration of reactive species and may cause insufficient surface fluorination. This work attempts to develop an atmospheric fluorocarbon plasma jet using a coaxial transmission line resonator by microwave discharge with locally enhanced electric field and high density. The gas temperature is reduced by pulse modulation technology. Three kinds of working gases, pure CF4, Ar/CF4 and He/CF4, are utilized to generate the atmospheric microwave fluorocarbon plasma jet. The discharge images, optical emission spectra, electron densities and gas temperatures are studied experimentally. The results show that the Ar/CF4 plasma jet has the best comprehensive performance, such as strong discharge intensity and controllable gas temperature. The electron density of the Ar/CF4 plasma jet has a magnitude of 1020 m−3, indicating a higher density than that of the frequently used dielectric barrier discharge. With the other conditions unchanged, the gas temperature at the end of the Ar/CF4 plasma jet can be reduced from 410.2 to 347.3 K by decreasing the duty cycle of the modulated pulse from 0.5 to 0.1. Thence, the microwave Ar/CF4 plasma jet is considered to be a promising fluorocarbon plasma source for surface fluorination of polymers. 相似文献
4.
An atmospheric non-thermal plasma jet was developed for sterilizing the Staphylococcus aureus (S. aureus). The plasma jet was generated by dielectric barrier discharge (DBD), which was characterized by electrical and optical diagnostics. The survival curves of the bacteria showed that the plasma jet could effectively inactivate 10 6 cells of S. aureus within 120 seconds and the sterilizing efficiency depended critically on the discharge parameter of the applied voltage. It was further confirmed by scanning electron microscopy (SEM) that the cell morphology was seriously damaged by the plasma treatment. The plasma sterilization mechanism of S. aureus was attributed to the active species of OH, N 2 + and O, which were generated abundantly in the plasma jet and characterized by OES. Our findings suggest a convenient and low-cost way for sterilization and inactivation of bacteria. 相似文献
5.
The Ar atmospheric pressure plasma was found to be an excellent laboratorial source for green aurora emission. However, the characteristic and production mechanism of the green aurora emission of the Ar atmospheric pressure plasma are still not clear. In this work, an Ar plasma in a long glass tube which emits intense green aurora light is investigated. With the long glass tube, it can be concluded that the green aurora emission in the Ar plasma is not owing to the mixture of Ar plasma plume with the surrounding air. It is also found that the green aurora emission often appeared beyond the active electrode when the active electrode is placed at the downstream of the gas flow. The green emission disappears when the traces amount of O2 or N2 (about 0.05%–0.07%) is added to Ar. This is because the O2 molecules deactivate the upper state O(1S), which results in the decrease of the green emission. On the other hand, when N2 is added, Ar metastable atoms are quenched by N2, which results in the decrease of O atoms and eventually leads to the decrease of the green emission intensity. The intensity of the green aurora emission increases when the driving voltage frequency increases from 1 to 10 kHz. More importantly, it is found that the green aurora emission is not affected when a grounded stainless steel needle is in contact with the plasma plume. Thus, the green emission is not driven electrically. All these findings are helpful for the understanding of the physics and its applications of atmospheric pressure plasma jet in space physics, laser physics and other application areas. 相似文献
6.
Study on an Atmospheric Pressure Plasma Jet and its Application in Etching Photo-Resistant Materials 总被引：1，自引：0，他引：1
An atmospheric pressure radio-frequency plasma jet that can eject cold plasma has been developed. In this paper, the configuration of this type of plasma jet is illustrated and its discharge characteristics curves are studied with a current and a voltage probe. A thermal couple is used to measure the temperature distribution along the axis of the jet stream. The temperature distribution curve is generated for the He/O2 jet stream at the discharge power of 150 W. This jet can etch the photo-resistant material at an average rate of 100 nm/min on the surface of silicon wafers at a right angle. 相似文献
7.
An atmospheric pressure plasma jet （APPJ） using radio-frequency （13.56 MHz） power has been developed to produce homogeneous glow discharge at low temperature. With optical emission spectroscopy, we observed the excited species （atomic helium, atomic oxygen and metastable oxygen） generated in this APPJ and their dependence on gas composition ratio and RF power. O and O2（b1∑g^＋） are found in the effluent outside the jet by measuring the emission spectra of effluent perpendicular to the jet. An interesting phenomenon is found that there is an abnormal increase of O emission intensity （777.4 nm） between 10 mm and 40 mm away from the nozzle. This observation result is very helpful in practical operation. 相似文献
8.
A remote plasma, also referred to as a plasma plume (diffuse or filamentary), is normally formed downstream of an atmospheric pressure plasma jet. In this study, a diffuse plume is formed by increasing the bias voltage (U b) applied to the downstream electrode of an argon plasma jet excited by a negatively pulsed voltage. The results indicate that the plume is filamentary when U b is low, which transits to the diffuse plume with increasing U b. The discharge initiated at the rising edge of the pulsed voltage is attributed to the diffuse plume, while that at the falling edge contributes to the filament in the plume. For the diffuse plume, the discharge intensity decreases with the increasing oxygen content (C o). Fast photography reveals that the diffuse plume results from a negative streamer, which has a dark region near the nozzle with C o = 0%. However, the dark region is absent with C o = 0.5%. From the optical emission spectrum, the electron density, electron excitation temperature, gas temperature, and oxygen atom concentration are investigated. 相似文献
9.
Acrylic polyurethane paint on the surface of 2A12 Al alloy was cleaned utilizing an atmospheric pressure plasma jet in this work. The dynamic evolution of the paint removal process during plasma treatment with time was explored through analysis of morphology and chemical states. The results showed that although the thickness of paint could be reduced effectively with an increase in cleaning time, the removal rate of paint gradually decreased with time. During the initial cleaning process range, its original smooth morphology of paint turned rugged quickly and was almost unchanged with further plasma treatment. Element and chemical state analysis showed that the content of C in the paint layer decreased obviously after plasma treatment. In contrast, the O content increased remarkably. The cleaning mechanism could be mainly attributed to the reaction between active O-containing species in air plasma and organic components in the paint. After removal of superficial organic matter, residue inorganic metal oxide substances aggregated on the base. The exposed metal oxides on the one hand elevated the superficial O content, but on the other hand hindered further plasma penetration, resulting in a gradual decrease in cleaning rate with cleaning time. Therefore, physical wiping was proposed to be incorporated with the plasma method and effective removal of paint was realized. 相似文献
10.
In this work, an Ar plasma jet generated by an AC-microsecond-pulse-driven dielectric barrier discharge reactor, which had two ring-shaped electrodes isolated from the ambient atmosphere by transformer oil, was investigated. By special design of the oil insulation, a chemically active Ar plasma jet along with a safe and stable plasma process as well as low emission of CO and NOx were successfully achieved. The results indicated that applied voltage and frequency were basic factors influencing the jet temperature, discharge power, and jet length, which increased significantly with the two operating parameters. Meanwhile, gas velocity affected the jet temperature in a reverse direction. In comparison with a He plasma jet, the Ar plasma jet had relatively low jet temperature under the same level of the input parameters, being preferable for bio-applications. The Ar plasma jet has been tested to interact with human skin within 5 min without the perception of burnt skin and electrical shock. 相似文献
11.
Electric field is an important parameter of plasma, which is related to electron temperature, electron density, excited species density, and so on. In this work, the electric field of an atmospheric pressure plasma jet is diagnosed by the electric field induced second harmonic (E-FISH) method, and the time-resolved electric field under different conditions is investigated. When positive pulse voltage is applied, the electric field has a peak of about 25 kV cm−1 at the rising edge of the voltage pulse. A dark channel is left behind the plasma bullet and the electric field in the dark channel is about 5 kV cm−1. On the other hand, when negative pulse voltage is applied, the electric field has a peak of −16 kV cm−1 when the negative voltage is increased to −8 kV. A relatively bright channel is left behind the plasma head and the electric field in this relatively bright channel is about −6 kV cm−1. When the pulse rising time increases from 60 to 200 ns, the peak electric field at both the rising edge and the falling edge of the voltage decreases significantly. When 0.5% of oxygen is added to the main working gas helium, the peak electric field at the rising edge is only about 15 kV cm−1. On the other hand, when 0.5% nitrogen is added, the peak electric field increases especially at the falling edge of the voltage pulse, where it increases reversely from −12 to −16 kV cm−1 (the minus sign only represents the direction of electric field). 相似文献
12.
Fengwu LIU 《等离子体科学和技术》2022,24(5):55408
The Ar atmospheric pressure plasma was found to be an excellent laboratorial source for green aurora emission. However, the characteristic and production mechanism of the green aurora emission of the Ar atmospheric pressure plasma are still not clear. In this work, an Ar plasma in a long glass tube which emits intense green aurora light is investigated. With the long glass tube, it can be concluded that the green aurora emission in the Ar plasma is not owing to the mixture of Ar plasma plume with the surrounding air. It is also found that the green aurora emission often appeared beyond the active electrode when the active electrode is placed at the downstream of the gas flow. The green emission disappears when the traces amount of O2 or N2 (about 0.05%–0.07%) is added to Ar. This is because the O2 molecules deactivate the upper state O(1S), which results in the decrease of the green emission. On the other hand, when N2 is added, Ar metastable atoms are quenched by N2, which results in the decrease of O atoms and eventually leads to the decrease of the green emission intensity. The intensity of the green aurora emission increases when the driving voltage frequency increases from 1 to 10 kHz. More importantly, it is found that the green aurora emission is not affected when a grounded stainless steel needle is in contact with the plasma plume. Thus, the green emission is not driven electrically. All these findings are helpful for the understanding of the physics and its applications of atmospheric pressure plasma jet in space physics, laser physics and other application areas. 相似文献
13.
K NAVANEETHA PANDIYARAJ D VASU P V A PADMANABHAN M PICHUMANI R R DESHMUKH V KANDAVELU 《等离子体科学和技术》2020,22(5):55504-055504
The intention of this work is to remove Reactive Blue 198(RB-198) dye components from simulated water solution using cold atmospheric pressure argon plasma jet. Aqueous solutions of RB-198 dye were treated as a function of various operating parameters such as applied potential,reaction time and distance between the plasma jet and surface of the liquid. The efficiency of the degradation of RB-198 molecules was explored by means of UV-Vis spectroscopy. The reactive species involved during the treatment process were examined by optical emission spectra(OES).The present hydroxyl radicals(OH·radical) and hydrogen peroxide(H_2O_2) in the plasma-treated aqueous dye solutions were investigated using various spectroscopic techniques. The other parameters such as total organic carbon(TOC), conductivity and p H were also reviewed. The toxicity of plasma-treated RB-198 solution was finally studied by diffusion bacterial analysis and by tracking seed germination processes. The results show that a higher degradation percentage of99.27% was acquired for the RB-198 treated at higher reaction time and applied potential, and shorter distance between the plasma jet and water surface. This may be due to the formation of various reactive oxygen(OH·radical, atomic oxygen(O) and H_2O_2) and nitrogen species(nitric oxide(NO) radicals and N_2 second positive system(N_2 SPS)) during the processes as confirmed by OES analysis and other spectroscopy analysis. TOC(17.7%-81.8%) and pH(7.5-3.4)values of the plasma-treated RB-198 decreased significantly with respect to various operation parameters, which indicates the decomposition of RB-198 molecules in the aqueous solution.Moreover, the conductivity of plasma-treated RB-198 aqueous solutions was found to have increased linearly during the plasma treatment due to the formation of various ionic species in aqueous solution. The toxicity analysis clearly exhibits the non-toxic behavior of plasma-treated RB-198 aqueous solution towards the bacterial growth and germination of seeds. 相似文献
14.
CHEN Bingyan 《等离子体科学和技术》2016,18(3):278-286
Discharge plasma in and in contact with water can be accompanied with ultraviolet radiation and electron impact,thus can generate hydroxyl radicals,ozone,nitrite nitrogen and hydrogen peroxide.In this paper,a non-equilibrium plasma processing system was established by means of an atmospheric pressure plasma jet immersed in water.The hydroxyl intensities and discharge energy waveforms were tested.The results show that the positive and negative discharge energy peaks were asymmetric,where the positive discharge energy peak was greater than the negative one.Meanwhile,the yield of ozone and nitrite nitrogen was enhanced with the increase of both the treatment time and the discharge energy.Moreover,the p H value of treated water was reduced rapidly and maintained at a lower level.The residual concentration of hydrogen peroxide in APPJ treated water was kept at a low level.Additionally,both the efficiency energy ratio of the yield of ozone and nitrite nitrogen and that of the removal of p-nitrophenol increased as a function of discharge energy and discharge voltage.The experimental results were fully analyzed and the chemical reaction equations and the physical processes of discharges in water were given. 相似文献
15.
CAO Yingguang YANG Ping LU Xinpei XIONG Zilan YE Tao XIONG Qing SUN Ziyong 《等离子体科学和技术》2011,13(1):93-98
Enterococcus faecalis (E. faecalis) is a microorganism that can survive extreme challenges in obturated root canals. The aim of this study was to evaluate the efficacy of a non-thermal atmospheric pressure plasma plume against E. faecalis in vitro. A non-thermal atmospheric pressure plasma jet device which could generate a cold plasma plume carrying a peak current of 300 mA was used. The antibacterial efficacy of this device against E. faecalis and its biofilm under different conditions was detected. The antibacterial efficacy of the plasma against E. faecalis and Staphylococcus aureus (S. aureus) was also evaluated. After plasma treatment, the average diameter of inhibition zone on S. aureus and E. faecalis was 2.62±0.26 and 1.06±0.30 cm, respectively (P < 0.05). The diameter was increased with prolongation of the treatment duration. The diameters of inhibition zone of the sealed Petri dishes were larger than those of the uncovered Petri dishes. There was significant difference in colony-forming units between plasma group and control group on E. faecalis biofilm (P < 0.01). The transmission electron microscopy revealed that the ultrastructural changes cytoderm of E. faecalis were observed after treatment for 2 min. It is concluded that the non-thermal atmospheric pressure plasma could serve as an effective adjunct to standard endodontic microbial treatment. 相似文献
16.
In this study,a high-density polyethylene（HDPE,5-mm-thick,0.95 g/cm3） surface was treated using an RF capacitive atmospheric pressure cold Ar plasma jet.By using this Ar plasma jet,a hydrophilic HDPE surface was formed during the plasma treatment.In particular, the effects of an additive gas（N2 or O2） on the HDPE surface treatment were investigated in detail.It was shown that the addition of N2 or O2 gas had an important influence on the HDPE surface treatment.Compared to pure Ar plasma treatment,a lower value of water contact angle （WCA） was obtained when a trace of N2 or O2 gas was added.It was also found that besides the quantities of active species in the plasma jet,the treatment temperature played an important role in the HDPE surface treatment.This is because surface molecular motion is not negligible when the treatment temperature is close to the melting point of the polymer. 相似文献
17.
To understand the self sustained propagation of the plasma jet/bullet in air under atmospheric pressure, the ignition of the plasma jet/bullet, the plasma jet/bullet ignition point in the plasma pencil, the formation time and the formation criteria from a dielectric barrier configured plasma pencil were investigated in this study. The results were confirmed by comparing these results with the plasma jet ignition process in the plasma pencil without a dielectric barrier. Electrical, optical, and imaging techniques were used to study the formation of the plasma jet from the ignition of discharge in a double dielectric barrier configured plasma pencil. The investigation results show that the plasma jet forms at the outlet of the plasma pencil as a donut shaped discharge front because of the electric field line along the outlet’s surface. It is shown that the required time for the formation of the plasma jet changes with the input voltage of the discharge. The input power calculation for the gap discharge and for the whole system shows that 56% of the average input power is used by the first gap discharge. The estimated electron density inside the gap discharge is in the order of 1011cm-3 . If helium is used as a feeding gas, a minimum 1.48×10-8C charge is required per pulse in the gap discharge to generate a plasma jet. 相似文献
18.
In this study, the effects of the fluid cooling and electric field line deformation were investigatedin a dielectric barrier discharge (DBD) plasma source. The DBD plasma jet is improved bycovering the ground electrode and a power electrode with insulating oil. We obtained positiveresults as insulating oil prevents arc formation, while it improved the supplied power and plasmajet length, and increased radical production. Radical production of this nonthermal plasma jet isstudied with polyvinyl alcohol–potassium iodide liquid. 相似文献
19.
This paper is aimed to show the influence of initial chemical pretreatment prior to subsequent plasma activation of aluminum surfaces.The results of our study showed that the state of the topmost surface layer（i.e.the surface morphology and chemical groups）of plasma modified aluminum significantly depends on the chemical precleaning.Commonly used chemicals（isopropanol,trichlorethane,solution of Na OH in deionized water）were used as precleaning agents.The plasma treatments were done using a radio frequency driven atmospheric pressure plasma pencil developed at Masaryk University,which operates in Ar,Ar/O2 gas mixtures.The effectiveness of the plasma treatment was estimated by the wettability measurements,showing high wettability improvement already after 0.3 s treatment.The effects of surface cleaning（hydrocarbon removal）,surface oxidation and activation（generation of OH groups）were estimated using infrared spectroscopy.The changes in the surface morphology were measured using scanning electron microscopy.Optical emission spectroscopy measurements in the near-to-surface region with temperature calculations showed that plasma itself depends on the sample precleaning procedure. 相似文献
20.
Yuyang WANG Cheng CHENG Peng GAO Shaopeng LI Jie SHEN Yan LAN Yongqiang YU 《等离子体科学和技术》2017,19(2):25503
An atmospheric-pressure air plasma is employed to treat C6 glioma cells in vitro.To elucidate on the mechanism causing cell death and role of reactive species(RS) in the medium produced by the plasma,the concentration of the long-lived RS such as hydrogen peroxide,nitrate,and ozone in the plasma-treated liquid(phosphate-buffered saline solution) is measured.When vitamin C is added to the medium as a ROS quencher,the viability of C6 glioma cells after the plasma treatment is different from that without vitamin C.The results demonstrate that reactive oxygen species(ROS) such as H_2O_2,and O_3 constitute the main factors for inactivation of C6 glioma cells and the reactive nitrogen species(RNS) may only play an auxiliary role in cell death. 相似文献
