Hannemann M.,Leibniz Institute for Plasma Science and Technology
Contributions to Plasma Physics | Year: 2013
The energy distribution, the mean energy and the density of the electrons of low pressure plasmas may be obtained from the 2nd derivative of a Langmuir probe characteristic. Often numerical methods are used for differentiation. A simple numerical technique is the non-recursive digital or FIR filtering. Because of noise this process has to comprise also smoothing elements. The best way to achieve this is the successive use of a weakly smoothing interpolation based twofold differentiating filter and a strong smoothing filter. None of the usual smoothing filters exhibits all properties needed in the evaluation of probe characteristics. Window function based FIR filters represent a class of smoothing filters which is especially suited in this context because of its increasing stop band attenuation. A new smoothing filter based on a new parameterized window function is introduced. The testing of this new filter is performed and hints for finding of the filter parameters are given © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Wendt M.,Leibniz Institute for Plasma Science and Technology
Journal of Physics D: Applied Physics | Year: 2011
The net emission coefficient of plasmas containing argon and iron at atmospheric pressure is calculated and analysed for the case of cylindrical geometry. Its values are obtained by integrating the monochromatic net emission coefficient taking into account continuous and line radiation. The width of the spectral lines is determined by Doppler broadening, natural, resonance, van der Waals, electron and ion Stark broadening. As Stark broadening is the most important broadening mechanism in the considered pressure and temperature range, the electron Stark widths are calculated following the semi-empirical Stark broadening theory. Additionally, the electron Stark widths of Ar, Ar +, Fe and Fe + are multiplied by scaling factors in order to reproduce experimental electron Stark widths. The scaling factor is determined for each species separately. For small plasma radii the net emission coefficient determined here shows good agreement with literature values where spherical geometry is considered while they decrease faster with increasing plasma radius. This behaviour is caused by the increase of the irradiation of the symmetry axis when cylindrical instead of spherical geometry is considered. For radii and temperatures typical of the metal filled core of arcs occurring in gas metal arc welding processes, i.e. radii between 1 and 2 × 10 -3 m and temperatures between 5000 and 10 000 K, the scaling of the Stark widths increases the net emission coefficient of iron plasmas by between 2% and 23%. In this parameter range the net emission coefficient of iron plasmas for cylindrical geometry is between 30% and 37% smaller than values calculated for spherical geometry. © 2011 IOP Publishing Ltd.
Leibniz Institute for Plasma Science and Technology | Date: 2010-08-12
A method and device for treatment of living cells with cold atmospheric pressure plasma while simultaneously applying selective electroporation of the cells are provided. The method is useful for the local selective killing of cancer cells, improvement of wound treatment and sterilization or decontamination of objects.
Leibniz Institute for Plasma Science, Technology and Neoplas Gmbh | Date: 2015-06-05
The invention relates to a device, preferably a collar, for treating areas of human or animal skin or mucous membrane with a cold atmospheric pressure plasma by creating a dielectrically hindered surface discharge, comprising at least one flexible insulating material (
Leibniz Institute for Plasma Science and Technology | Date: 2011-05-09
The invention relates to a method and to a device for quickly decontaminating and sterilizing preferably thermolabile goods using a plasma gas that is preferably generated from air as a process gas, with the subsequent humidification of said plasma gas with water. The method comprises the following steps: generating a plasma from air as the process gas, which forms reactive nitrogen and oxygen species; oxidizing NO to form NO