Simulations are conducted on capacitively coupled Ar/O_(2)mixed gas discharges employing a one-dimensional fluid coupled with an electron Monte Carlo(MC)model.The research explores the impact of different O_(2)ratio a...Simulations are conducted on capacitively coupled Ar/O_(2)mixed gas discharges employing a one-dimensional fluid coupled with an electron Monte Carlo(MC)model.The research explores the impact of different O_(2)ratio and pressures on the discharge characteristics of Ar/O_(2)plasma.At a fixed Ar/O_(2)gas ratio,with the increasing pressure,higher ion densities,as well as a slight increase in electron density in the bulk region can be observed.The discharge remains dominated by the drift-ambipolar(DA)mode,and the flux of O(3P)at the electrode increases with the increasing pressure due to higher background gas density,while the fluxes of O(1D)and Ardecrease due to the pronounced loss rate.With the increasing proportion of O_(2),a change in the dominant discharge mode from a mode to DA mode can be detected,and the O_(2)-associated charged particle densities are significantly increased.However,Ar+density shows a trend of increasing and then decreasing,while for neutral fluxes at the electrode,Arflux decreases,and O(3P)flux increases with the reduced Ar gas proportion,while trends in O(1D)flux show slight differences.The evolution of the densities of the charged particle and the neutral fluxes under different discharge parameters are discussed in detail using the ionization characteristics as well as the transport properties.Hopefully,more comprehensive understanding of Ar/O_(2)discharge characteristics in this work will provide a valuable reference for the industry.展开更多
Radio frequency capacitively coupled plasmas(RF CCPs)play a pivotal role in various applications in etching and deposition processes on a microscopic scale in semiconductor manufacturing.In the discharge process,the p...Radio frequency capacitively coupled plasmas(RF CCPs)play a pivotal role in various applications in etching and deposition processes on a microscopic scale in semiconductor manufacturing.In the discharge process,the plasma series resonance(PSR)effect is easily observed in electrically asymmetric and geometrically asymmetric discharges,which could largely influence the power absorption,ionization rate,etc.In this work,the PSR effect arising from geometrically and electrically asymmetric discharge in argon-oxygen mixture gas is mainly investigated by using a plasma equivalent circuit model coupled with a global model.At relatively low pressures,as Ar content(α)increases,the inductance of the bulk is weakened,which leads to a more obvious PSR phenomenon and a higher resonance frequency(ω_(psr)).When the Ar content is fixed,varying the pressure and gap distance could also have different effects on the PSR effect.With the increase of the pressure,the PSR frequency shifts towards the higher order,but in the case of much higher pressure,the PSR oscillation would be strongly damped by frequent electron-neutral collisions.With the increase of the gap distance,the PSR frequency becomes lower.In addition,electrically asymmetric waveforms applied to a geometrically asymmetric chamber may weaken or enhance the asymmetry of the discharge and regulate the PSR effect.In this work,the Ar/O_(2) electronegative mixture gas is introduced in a capacitive discharge to study the PSR effect under geometric asymmetry effect and electrical asymmetry effect,which can provide necessary guidance in laboratory research and current applications.展开更多
Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transfo...Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous catalysts in the presence of H2O2. The experimental result indicated that the synthetic materials had a high catalytic activity and good reusability.展开更多
A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The resul...A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The results showed that the Fe3O4 nanoparticles existed steadily on the surface of coke,with better dispersing and smaller particle size.The catalytic ability of Fe3O4/Coke were investigatied by degrading p-nitrophenol（P-NP）.The results showed that the apparent rate constant for the P-NP at 1.0 g·L^-1 catalyst,30 mmol·L^-1 H2O2,pH=3.0,30 ℃ and the best ratio of Coke/Fe3O4 0.6,was evaluated to be 0.027 min^-1,the removalrate of CODCr was 75.47%,and the dissolubility of Fe was 2.42 mg·L^-1.Compared with pure Fe3O4,the catalytic ability of Fe3O4/Coke in the presence of H2O2 was greatly enhanced.And Fe3O4/Coke was a green and environmentalcatalyst with high catalytic activity,showing a good chemicalstability and reusability.展开更多
基金the National Natural Science Foun-dation of China(Grant Nos.12020101005,11975067,and 12347131)the Fundamental Research Funds for the Cen-tral Universities(Grant No.DUT24BS069).
文摘Simulations are conducted on capacitively coupled Ar/O_(2)mixed gas discharges employing a one-dimensional fluid coupled with an electron Monte Carlo(MC)model.The research explores the impact of different O_(2)ratio and pressures on the discharge characteristics of Ar/O_(2)plasma.At a fixed Ar/O_(2)gas ratio,with the increasing pressure,higher ion densities,as well as a slight increase in electron density in the bulk region can be observed.The discharge remains dominated by the drift-ambipolar(DA)mode,and the flux of O(3P)at the electrode increases with the increasing pressure due to higher background gas density,while the fluxes of O(1D)and Ardecrease due to the pronounced loss rate.With the increasing proportion of O_(2),a change in the dominant discharge mode from a mode to DA mode can be detected,and the O_(2)-associated charged particle densities are significantly increased.However,Ar+density shows a trend of increasing and then decreasing,while for neutral fluxes at the electrode,Arflux decreases,and O(3P)flux increases with the reduced Ar gas proportion,while trends in O(1D)flux show slight differences.The evolution of the densities of the charged particle and the neutral fluxes under different discharge parameters are discussed in detail using the ionization characteristics as well as the transport properties.Hopefully,more comprehensive understanding of Ar/O_(2)discharge characteristics in this work will provide a valuable reference for the industry.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.12020101005 and 11975067)。
文摘Radio frequency capacitively coupled plasmas(RF CCPs)play a pivotal role in various applications in etching and deposition processes on a microscopic scale in semiconductor manufacturing.In the discharge process,the plasma series resonance(PSR)effect is easily observed in electrically asymmetric and geometrically asymmetric discharges,which could largely influence the power absorption,ionization rate,etc.In this work,the PSR effect arising from geometrically and electrically asymmetric discharge in argon-oxygen mixture gas is mainly investigated by using a plasma equivalent circuit model coupled with a global model.At relatively low pressures,as Ar content(α)increases,the inductance of the bulk is weakened,which leads to a more obvious PSR phenomenon and a higher resonance frequency(ω_(psr)).When the Ar content is fixed,varying the pressure and gap distance could also have different effects on the PSR effect.With the increase of the pressure,the PSR frequency shifts towards the higher order,but in the case of much higher pressure,the PSR oscillation would be strongly damped by frequent electron-neutral collisions.With the increase of the gap distance,the PSR frequency becomes lower.In addition,electrically asymmetric waveforms applied to a geometrically asymmetric chamber may weaken or enhance the asymmetry of the discharge and regulate the PSR effect.In this work,the Ar/O_(2) electronegative mixture gas is introduced in a capacitive discharge to study the PSR effect under geometric asymmetry effect and electrical asymmetry effect,which can provide necessary guidance in laboratory research and current applications.
基金Funded by the Specialized Research Fund for the Doctoral Program of Higher Education of China(20114219110002)the Natural Science Foundation of Hubei Province(Nos.2014CFB810&2014CFB812)
文摘Magnetically modified Fe-Al pillared bentonite（Fe3O4/ Fe-Al-Bent） was prepared via chemical co-precipitation method and characterized by powder X-ray diffraction（XRD）, Brunauer-EmmettTeller（BET）, Fourier transform infrared spectroscopy（FTIR） and scanning electron microscopy（SEM）. A series of experiments were carried out to investigate the degradation of Orange II by the obtained heterogeneous catalysts in the presence of H2O2. The experimental result indicated that the synthetic materials had a high catalytic activity and good reusability.
基金Funded by the Specialized Research Fund for Doctoral Program of Higher Education of China(No.20114219110002)the Educational Department of Hubei Province of China(No.D20131107)the Natural Science Fundation of Hubei Provice(No.2014CFB810)
文摘A composite material（Fe3O4/Coke）using coke supported Fe3O4 magnetic nanoparticles was successfully prepared via an in-situ chemicaloxidation precipitation method and characterized by SEM,XRD,Raman,and FTIR.The results showed that the Fe3O4 nanoparticles existed steadily on the surface of coke,with better dispersing and smaller particle size.The catalytic ability of Fe3O4/Coke were investigatied by degrading p-nitrophenol（P-NP）.The results showed that the apparent rate constant for the P-NP at 1.0 g·L^-1 catalyst,30 mmol·L^-1 H2O2,pH=3.0,30 ℃ and the best ratio of Coke/Fe3O4 0.6,was evaluated to be 0.027 min^-1,the removalrate of CODCr was 75.47%,and the dissolubility of Fe was 2.42 mg·L^-1.Compared with pure Fe3O4,the catalytic ability of Fe3O4/Coke in the presence of H2O2 was greatly enhanced.And Fe3O4/Coke was a green and environmentalcatalyst with high catalytic activity,showing a good chemicalstability and reusability.
