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We report on an observation of bi-directional 656 nm lasing action of atomic hydrogen in a premixed CH4∕air flame induced by resonant femtosecond 205 nm two-photon excitation. In particular, the backward-propagating lasing pulse is characterized in the spatial and temporal domains for the sake of a single-ended diagnostic. Its picosecond-scale duration and smooth temporal profile enable spatially
We suggest two methods for simulating from a multivariate copula in an arbitrary dimension. Although our main emphasis in this paper is on multivariate extreme value distributions, the proposed methods can be applied to any copula. The basic idea is to approximate the (unknown) density of the copula by a distribution that has a piece‐wise constant (histogram) density. This is achieved by partition
Consider the process which starts with N ≥ 3 distinct points on ℝd, and fix a positive integer K < N. Of the total N points keep those N - K which minimize the energy amongst all the possible subsets of size N - K, and then replace the removed points by K independent and identically distributed points sampled according to some fixed distribution ζ. Repeat this process ad infinitum. We obtain vario
This paper contains a study of the extent to which aggregate losses due to severe wind storms can be explained by wind measurements. The analysis is based on 12 years of data for a region, Ska § ne, in southern Sweden. A previous investigation indicated that wind measurements from six recording stations in Ska § ne was insufficient to obtain accurate prediction. The present study instead uses geos
”Vd har ordet” är det avsnitt i årsredovisningen som många anser vara allra viktigast och mest läst. Men vilken berättelse, eller snarare vilka berättelser, om företaget är det som lämnas under rubriken ”Vd har ordet”? I en studie av 30 årsredovisningar har olika berättelser identifierats, såsom exempelvis den kamerala berättelsen och den strategiska berättelsen. I denna artikel beskrivs och utvec
By means of the beam-foil method, 74 new lines have been identified as combinations between the core-excited 2p5 3s3p, 3s3d and 3p2 configurations in Na-like sulphur, chlorine, argon and titanium. Relative energies have been determined for most of the quartet levels in S, Cl and Ar with an internal uncertainty of less than 25 cm−1. We also report the first observation in the isoelectronic sequence
The spectrum of Ti XFV has been observed in the wavelength region 80-550 Å using the fast ion beam spectroscopy method. 47 lines have been identified as transitions between the 2p4 3s, 3p, and 3d configurations in the 360-540 Å interval. The level identifications are supported by comparisons between observations and Hartree-Fock calculations along the F I isoelectronic sequence.
Using the beam-foil excitation technique and the ANDC method for cascade corrections, we have determined lifetimes of the 2s2p22S, 2s2ns2S (n = 3, 4, 5), 2s2p22P, 2s2p2P° (n = 3, 4), and 2p32P° terms in CII and the 2s2p1P0 level in C III. The new experimental lifetimes are in very good agreement with the results of recent theoretical calculations.
Using the method of beam-foil spectroscopy we have measured the decay times of several n = 3 terms in Mg-like Ni XVII. By applying an effective method for correction of cascades (ANDC) we obtained reliable lifetimes for the terms 3s3p1P, 3s3p3P, 3p21D and 3p2 3P. The experimental data are in good agreement with recent theoretically predicted values.
Intensity decays of the 3s3p2 S2,2P,2D, 3p3 P2,2D, 3s3p(3P)3d D2, 3s3p(1P)3d F2, 3s23d D2, 4s S2, 4p P2, 5p P2, 4d2D, and 4f 2F states in S S IV have been recorded using the beam-foil technique. The arbitrarily normalized decay curves method for cascade corrections has been applied to obtain accurate lifetimes for 11 of the 18 levels studied. Theoretical lifetimes for these levels, obtained in a s
In the EUV spectrum of foil-excited 24 MeV Ni ions the decays of the 3 s 3 p3 and 3 s2 3 p 3 d levels to the 3 s2 3 p2 levels of the ground configuration have been observed. For most of the levels decay curves have been obtained. The lifetime results compare well with predictions from semi-empirically scaled HXR calculations. Some problems with cascade repopulations will be discussed.
An experimental and theoretical study has been made of the 3s-3p and 3p-d transitions in Ni XIX. The method of beam-foil spectroscopy, using 30-64 MeV Ni ions from a tandem accelerator, has been combined with theoretical calculations using the multiconfiguration Dirac-Fock (MCDF) program.
Lifetime measurements, based on the method of beam-foil spectroscopy, together with careful corrections for cascade effects, have in recent years yielded the line strength of the 2s2 1S-2s2p 1P°transition in Be-like ions with uncertainties ranging from 3.4% to 8.1% in Bei-O. By applying a method of isoelectronic smoothing of line strengths, similar to those earlier used for excitation energies and
The intensity ratio of the two fine structure components in the 3s23p 2PJ–3s3p 2S1/2 and 2P1/2 resonance transitions has been measured in Al-like S IV, Cl V, Ar VI and Ti X, using the beam-foil technique. Unexpectedly large deviations from the LS ratios are found, particularly in the 2P–2S case. Although these deviations can be understood qualitatively from theoretical calculations (also reported)
Experimental lifetimes of several levels in the 2p5 3p and 3d configurations in Ne-like sulphur, S VII, and argon, Ar IX, have been determined by the beam-foil technique. The ANDC method for cascade correction has been applied in the analyses of the 3p decay curves. The results are generally in good agreement with recent theoretical values except for the 3p 3D levels for which significant deviatio
Experimental lifetimes of seven 2p53p and six 2p53d levels in Ne-like chlorine, Cl VIII, have been measured using the beam-foil technique. For the first time in the Ne-sequence, the ANDC method of cascade correction has been applied in the lifetime determination of the 3p levels. This procedure lowered the values by 10 to 30% compared to the results from multiexponential curve-fitting. For all lev
The n = 0 transition multiplet connecting the lowest quartet states of doubly excited C IV has been studied by beam-foil spectroscopy. The fine structure splittings obtained for the 1s2s2p 4p0and 1s2p2 4p terms confirm previous experimental results with an improved accuracy. The average transition wavelength = (1344.49 0.04)A is now more precisely determined by about a factor of eight. At the new
