Observations of extreme ultraviolet emission from plasma produced by capillary discharges

This study reports the results of a pilot experiment concerning observations of extreme ultraviolet emission from plasma produced by the capillary discharges. A few kA current was applied across the gas-filled alumina capillary (1 mm diameter and 8 mm long) to generate radiation in the EUV region (12–63 nm). Spectroscopic studies were carried out by means of a XEUV spectrometer which was upgraded for special lithography purposes. The results obtained from the EUV spectroscopic measurements provided information about the radiation processes from xenon and argon plasma and testifies that given capillary is an effective source of EUV emission. Additionally we showed a simulation which describes plasma dynamics parameters and dynamics of various ionization stages in capillary discharge. Our computer simulation confirmed the presence of ions, which spectra was registered in the experiment.     

Extended analysis of the six-times ionized xenon, Xe VII

The spectrum of six-times ionized xenon, Xe VII, has been studied in the 270–6,500 ? using a pulsed discharge. 110 new classified lines are reported. Ten levels belonging to the odd parity configurations and four belonging to the even configurations have been determined. To obtain the energy parameters Hartree-Fock relativistic calculations were used. Least-squares parametric calculation has been carried out to study the fit between experimental and theoretical values. Received 11 December 2000     

Experimental transition probabilities and improved level energies in Yb III

Radiative lifetimes of nine out of the twelve 4f¹³6p levels in Yb III have been measured, seven of these for the first time. A Penning discharge lamp is introduced as a continuous plasma source, in which the lifetimes are determined with the time-resolved laser-induced fluorescence technique by pumping from metastable 5d and 6s levels. Spectra of the same source are recorded with a Fourier-transform spectrometer, which are used to derive branching fractions of the 6p and 7s levels. Combined with the lifetimes, the branching fractions are used to determine 81 experimental transition probabilities. Wavelengths of 142 Yb III transitions are measured and the uncertainties of corresponding Ritz wavenumbers are improved by an order of magnitude from the prior values. The energy of the 5d (5/2,5/2)^○ ₀ level has been shifted 144.20 cm^-1 to the higher value 45421.045 cm^-1. Much emphasis is put on data treatment and error analysis. Electronic supplementary material Supplementary Online Material     

Supercapacitive operational mode in microbial fuel cell

Supercapacitive microbial fuel cells (SC-MFCs) are an emerging and promising field that has captured the attention of scientists in the past few years. This hybridization consists in the integration of supercapacitive features in the MFC electrodes to boost the performance output. The MFC anaerobic and aerobic enviroments induce self-polarization of the electrodes. The electrodes can be discharged galvanostatically and then self-recharged by the biotic/abiotic environments. During the discharge, two main phenomena named electrostatic and faradaic take place but the separation and quantification of the two contributes seems to be challenging. Galvanostatic discharges of SC-MFC produce at least one order of magnitude higher current/power compared with continuous operations, making it promising for pulsed type applications.     

Millimeter-wave spectrum of BrCN produced by dc discharge

Ground state (v=0) and first excited state (v=1) millimeter-wave rotational absorption spectra of cyanogen bromide (BrCN) and some of its isotopic species, have been investigated in the frequency region: 40.0-75.0 GHz using a source-modulated millimeter-wave spectrometer. Millimeter-wave radiation has been produced using a frequency multiplier, the fundamental radiation source being klystrons. BrCN has been produced by applying a dc glow discharge through a mixture of 3-bromobenzonitrile and trifluoromethylbromide (CF₃Br) at low pressure. The quadrupole hyperfine structure of ⁸¹Br and ⁷⁹Br have been resolved, measured, and analyzed. Finally, internuclear distances of BrCN have been determined.     

A spectroscopic investigation of stabilized dc argon arc at atmospheric pressure by power modulation technique

Spatial distribution of delayed responses of argon and hydrogen spectral line and continuum intensity to square power modulation was investigated in order to get better insight into the processes occurring in argon dc arc plasma. The power was abruptly changed between stationary values, 9 and 3.5 A. For these currents steady state radial distributions of electron number density, temperature and emission intensity were measured. On part of the discharge radial profiles the power drop and the power jump are both accompanied by intensity peaks which may be explained by displacement of the arc core axis and change in the arc core diameter during the power modulation.