Pulsed microwave plasma

Deilmann, M. Thei6, S. Awakowicz, P. (2008). Pulsed microwave plasma polymerization of silicon oxide films Application of efficient permeation barriers on polyethylene terephthalate. Surf Coat Technol, Vol. 202, pp. 1911-1917 Deilmann, M. Halfmann, H. Steves, S. Bibinov, N. Awakowicz, P. (2009). Silicon oxide permeation barrier coating and plasma sterilization of PET bottles and foils. Plasma Process, Polym., Vol. 6, pp. S695-S699... 

Baeva, M., Gier, H., Pott, A. et al. (2002) Pulsed microwave discharge at atmospheric pressure for NOx decomposition, Plasma Sources Sci. Technol. 11, 1-9. 

Selective synthesis of acetylene (>90%) from methane was accomplished by microwave plasma reactions.568 Conversion of methane to acetylene by using direct current pulse discharge was performed under conditions of ambient temperature and atmospheric pressure.569 The selectivity of acetylene was >95% at methane conversion levels ranging from 16 to 52%. In this case oxygen was used to effectively remove deposited carbon and stabilize the state of discharge. Similar high... 

As mentioned before, two interlaboratory studies were organised prior to certification, involving ca. 15 laboratories using techniques such as cold vapour atomic absorption spectrometry, direct current plasma atomic emission spectrometry (DCP-AES), differential pulse anodic stripping voltammetry (DPASV), microwave plasma atomic emission spectrometry (MIP-AES), electrothermal atomic absorption spectrometry (ETAAS) and neutron activation analysis with radiochemical separation (RNAA). 

An afterglow microwave plasma with stabilized pulse power was applied to the activation of zeolite catalysts for isobutane alkylation with butenes. It was found that the pretreatment of zeolite catalysts in a microwave plasma discharge affected their properties. The catalysts exhibited higher activity, stability in operation, and selectivity (the fraction of trimethylpentanes in the alkylate increased). The properties of catalysts after plasma activation depend on the treatment conditions such as plasma temperature and nonequilibrium character and depend only slightly on the initial activity of catalysts, which is primarily controlled by the catalyst preparation conditions. 

Figure 9-35. Permeability of the lestosil polymer membrane with respect to He, H2, CO2, and CH4 as function of microwave plasma treatment time o, Hne A, Hhj , Hcch +, ncH< microwave pulse power2 kW pulsing period 2 ms pulse duration 100 fis gas pressure in the microwave discharge chamber2 Torr nitrogen/oxygen ratio in the plasma gas N2 02 = 4 1 flow rate of the plasma gas 40 cm /s.

In the cross modulation experiments (Mentzoni and Row, 1963 Mentzoni and Rao, 1965), an electron plasma is briefly heated by a microwave pulse while a weak microwave signal probes the mean electron energy. Assuming no electron loss and insignificant ambient gas heating, these authors derived the following equation for the relaxation of electron Maxwellian temperature T.toward the ambient temperature T ... 

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