The microwave （MW） transmission method is employed to measure both the plasma density and the plasma decay time in the hollow cathode discharge （HCD） in argon at low pressure. The plasma density in DC-driven or pu...The microwave （MW） transmission method is employed to measure both the plasma density and the plasma decay time in the hollow cathode discharge （HCD） in argon at low pressure. The plasma density in DC-driven or pulsed HCD is on the order of 1012 cm-3, which can block the X-band MW effectively. In the case of pulsed HCD, the MW transmittance shows the same waveform as the pulsed current during the rising edge if the driving frequency is low, but with a longer delay during the falling edge. The MW transmittance reaches a constant low level when the driving frequency is high enough. The plasma decay time in the HCD system is measured to be about 100 μs around a pressure of 120 Pa. The ambipolar diffusion is considered to be the major mechanism in the decay process.展开更多
Transmission measurements of warm dense iron plasma are reported over the photon energy range of 400-1200 e V, including the strong 2p-3d structures. One-dimensional hydrodynamic simulation is performed to estimate th...Transmission measurements of warm dense iron plasma are reported over the photon energy range of 400-1200 e V, including the strong 2p-3d structures. One-dimensional hydrodynamic simulation is performed to estimate the plasma conditions： temperatures of several eV and densities of about O. 1 g/cm3. By using the simulated tempera- ture and density, the calculations of the transmission spectra are performed and compared with the time-resolved experimental results.展开更多
in this paper, an experimental research the effect of ablating material on the reflection and the transmission of microwaves in arc-heated plasma flow is presented by using the C band microwave measuring system. The ...in this paper, an experimental research the effect of ablating material on the reflection and the transmission of microwaves in arc-heated plasma flow is presented by using the C band microwave measuring system. The results show that the ablating material with accidented surface and its high temperature have remarkably affected the reflection and the transmission of microwaves. The experiment proves that the system has outstanding precision and reliability.展开更多
Synthesis of silicon carbide has been carried out using thermal plasma processing technique using SiO2 as the solid feed and CH4 as the gaseous reducing agent. Thermochemical calculations have been performed varying t...Synthesis of silicon carbide has been carried out using thermal plasma processing technique using SiO2 as the solid feed and CH4 as the gaseous reducing agent. Thermochemical calculations have been performed varying the molar ratio of silicon dioxide and methane to determine the feasibility of the reaction. Experiments using a molar ratio of SiO2：CH4 equal to 1：2 produced maximum yield of SiC of about 65 mol % at a solid feed rate of 5 g/min. Mostly spherical morphology with some nanorods has been observed. The presence of Si had been observed and was quantified using XRD, HRTEM, Raman spectroscopy and X-ray photoelectron microscopy （XPS）. Si acts as a nucleating agent for SiC nanorods to grow.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11005009)
文摘The microwave （MW） transmission method is employed to measure both the plasma density and the plasma decay time in the hollow cathode discharge （HCD） in argon at low pressure. The plasma density in DC-driven or pulsed HCD is on the order of 1012 cm-3, which can block the X-band MW effectively. In the case of pulsed HCD, the MW transmittance shows the same waveform as the pulsed current during the rising edge if the driving frequency is low, but with a longer delay during the falling edge. The MW transmittance reaches a constant low level when the driving frequency is high enough. The plasma decay time in the HCD system is measured to be about 100 μs around a pressure of 120 Pa. The ambipolar diffusion is considered to be the major mechanism in the decay process.
基金Supported by the National Natural Science Foundation of China under Grant No 11304292the Foundation of China Academy of Engineering Physics under Grant No 2013A0102002
文摘Transmission measurements of warm dense iron plasma are reported over the photon energy range of 400-1200 e V, including the strong 2p-3d structures. One-dimensional hydrodynamic simulation is performed to estimate the plasma conditions： temperatures of several eV and densities of about O. 1 g/cm3. By using the simulated tempera- ture and density, the calculations of the transmission spectra are performed and compared with the time-resolved experimental results.
文摘in this paper, an experimental research the effect of ablating material on the reflection and the transmission of microwaves in arc-heated plasma flow is presented by using the C band microwave measuring system. The results show that the ablating material with accidented surface and its high temperature have remarkably affected the reflection and the transmission of microwaves. The experiment proves that the system has outstanding precision and reliability.
文摘Synthesis of silicon carbide has been carried out using thermal plasma processing technique using SiO2 as the solid feed and CH4 as the gaseous reducing agent. Thermochemical calculations have been performed varying the molar ratio of silicon dioxide and methane to determine the feasibility of the reaction. Experiments using a molar ratio of SiO2：CH4 equal to 1：2 produced maximum yield of SiC of about 65 mol % at a solid feed rate of 5 g/min. Mostly spherical morphology with some nanorods has been observed. The presence of Si had been observed and was quantified using XRD, HRTEM, Raman spectroscopy and X-ray photoelectron microscopy （XPS）. Si acts as a nucleating agent for SiC nanorods to grow.
