An yttrium Mξ source for ESCA

A new source for producing YMξ radiation in an ESCA spectrometer is described. The system makes use of continuous evaporation of yttrium on a rotating anode. It is demonstrated that this scheme allows YMξ-excited electron spectra to be recorded without gradual loss of resolution and intensity due to anode oxidation. Electron spectra of Ar, Hg and N₂ excited by YMξ radiation are studied. Relative photoelectric cross-sections of the 5d_{$\text{5}\text{2}$}, 5d_{$\text{5}\text{2}$} and 6s orbitals in Hg and the four valence orbitals in N₂ are measured. The valence electron shake-up spectrum of N₂ is discussed.     

Die zerstörungsfreie Bestimmung der Seltenen Erdelemente nach der Neutronenaktivierung

The technique of INAA for the determination of the rare earth elements with respect to prospecting and production testing of polishing powders on the basis of rare earth element oxides as well as quality testing of ultragrade rare earth compounds is discussed.In order to count -radiation of the radioactive nuclei a Ge-Li-detector as well as a planar Ge-Li-detector have been used. The latter enables the evaluation of the low energetic side of the -spectrum without complicated corrections due to -line interferences. Therefore an efficient working procedure with respect to the determination of the distribution pattern of the rare earth elements is possible.A simple correction program however is necessary with respect to the use of the planar detector type, allowing for effects of self-absorption geometry of the sample as well as distance sample-detector. This program is also given in the paper.

     

Indications about the shape of the universe from the Wilkinson microwave anisotropy probe data

It is shown that the recent observations of NASA's Explorer mission, "Wilkinson Microwave Anisotropy Probe," hint that our Universe may possess a nontrivial topology. As an example we discuss the Picard space which is stretched out into an infinitely long horn but with finite volume.     

Review of the book <Emphasis Type="Italic">Optics of Microstructured Fibers</Emphasis> by A.M. Zheltikov (Nauka,Moscow, 2004)

Chronicle

Review of the book Optics of Microstructured Fibers by A.M. Zheltikov (Nauka, Moscow, 2004)     

Dynamical zero-temperature phase transitions and cosmic inflation or deflation

For a rather general class of scenarios, sweeping through a zero-temperature phase transition by means of a time-dependent external parameter entails universal behavior: In the vicinity of the critical point, excitations behave as quantum fields in an expanding or contracting universe. The resulting effects such as the amplification or suppression of quantum fluctuations (due to horizon crossing, freezing, and squeezing) including the induced spectrum can be derived using the curved space-time analogy. The observed similarity entices the question of whether cosmic inflation itself might perhaps have been such a phase transition.     

Quasiregular concentric waves in heterogeneous lattices of coupled oscillators

We study the pattern formation in a lattice of locally coupled phase oscillators with quenched disorder. In the synchronized regime quasiregular concentric waves can arise which are induced by the disorder of the system. Maximal regularity is found at the edge of the synchronization regime. The emergence of the concentric waves is related to the symmetry breaking of the interaction function. An explanation of the numerically observed phenomena is given in a one-dimensional chain of coupled phase oscillators. Scaling properties, describing the target patterns are obtained.     

Vacuum Cerenkov radiation

Within the classical Maxwell-Chern-Simons limit of the standard-model extension, the emission of light by uniformly moving charges is studied confirming the possibility of a Cerenkov-type effect. In this context, the exact radiation rate for charged magnetic point dipoles is determined and found in agreement with a phase-space estimate under certain assumptions.