Controlling of reactive species in atmospheric Ar bubble discharge by adding N 2 /O 2 a

et al. 2019

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Transitions between the streamer and spark modes affect the stability of gas–liquid discharges, limiting their practical applications, while the nature of such transitions is poorly understood. Here we clarify the often neglected effect of a dielectric on the gas–liquid discharge stability, using direct and indirect grounding configurations. Discharge modes and plasma characteristics in these two configurations are investigated. The discharge appears in a transient spark mode in the direct grounding while in a streamer mode in the indirect case. It is shown that the dielectric significantly improves the discharge stability. The gas temperature and electron density in the transient spark are 380 K and 1017/cm3 with a 30 kV pulse voltage, respectively, which are higher than those in the streamer mode.

Section: Resultsmentioning

confidence: 99%

Mode transition and plasma characteristics of nanosecond pulse gas–liquid discharge: Effect of grounding configuration

Wang

Yang

et al. 2019

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“…When a small amount of O 2 is added, O 2 mixed in plasma is dissociated O 2 and emitted O level from 3p 5 P to 3s 5 S by high‐energy free electrons. If O 2 is beyond a certain level, O 2 as an electronegative gas would strongly attract electrons in plasma, making more electrons attached by oxygen‐related species and trapped into the bulk area instead of forming the conductive current . As a result, the N 2 + (B) decreases with the increase of O 2 proportion due to quenching of electrons and metastable He atoms.…”

Section: Resultsmentioning

confidence: 99%

Investigation of mode interconversion for interfacial pattern formation through plasma–surface interaction

Liu

et al. 2019

The appropriate understanding of the plasma-surface interaction is crucial in optimizing the atmospheric pressure plasma jet (APPJ) to suit a particular application. In this study, we mainly focus on the behavior of mode interconversion for interfacial patterns regarding APPJ interacting with a indium tin oxide (ITO) glass substrate. By regulating the pulse voltage, annular interfacial pattern formation on ITO surface displays two types of modes, that is, the diffuse pattern and the streamer pattern. Furthermore, these two modes are not independent and are trans-2017BSHYDZZ11), the Natural Science Foundation of Shaanxi Province (Grant No. 2019JQ220), and the State F I G U R E 8 A schematic map for the pattern mode interconversion between diffuse and streamer by controlling the voltage and introducing N 2 and O 2 . The time-integrated images of interfacial pattern are taken with 100 µs gating time and 20 accumulations LIU ET AL.

“…For pH measurement of liquid, a basic pH meter is used (PB‐10, Sartorius, Germany), and the initial pH values of deionized water and d ‐mannitol solution are 5.67 and 5.76, respectively. In previous works, we have investigated the variation of the concentrations of H 2 O 2 ,

{NO}_{3}^{-}

, and

{NO}_{2}^{-}

measured in time with Ar bubble discharge, and found that all above concentrations increase almost linearly. In this study, most of data are for a plasma treatment of 8 min, because the RONS concentrations are moderate for measurement in such condition.…”

Section: Methodsmentioning

confidence: 98%

“…Figure a shows the schematic diagram of the experiment setup of underwater bubble discharge. This setup is identical to that used in the experiments described previously . The discharge reactor consists of a quartz reaction vessel, a stainless steel high voltage (HV) needle electrode, and a copper coil ground electrode.…”

Section: Methodsmentioning

confidence: 99%

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Measurement of reactive species in different solutions of bubble discharge with varying O₂/N₂ proportion in Ar: Analysis of reaction pathways

Zhao

Liang

et al. 2019

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The generation of species in gas phase and long-lived species in deionized water and D-mannitol solution of a bubble discharge in dependence on bubbled gas atmosphere with different O 2 /N 2 proportion are studied. Argon is mixed to enhance the discharge. The optical emission spectra and Fouriertransform infrared spectroscopy are used to diagnose gaseous species and exhaust gas components, and study the effects of O 2 /N 2 proportion on the species intensities. The aqueous species and OH radical are measured by chemical probes to reveal the role of OH radical on the formation of long-lived species. The liquid species and exhaust gas are also analyzed varying with O 2 /N 2 proportion to demonstrate the effect of O 2 -based radicals on the formation of long-lived species.