Luminescence and lifetime characteristics of microphases in KCl:KI:Pb mixed crystals

Absorption and luminiscence measurements were performed on lead-doped KCl:KI mixed single crystals. Strong differences were found between as-grown and quenched samples. New bands were observed in the absorption spectra of unquenched samples in the spectral region between the limit positions of the A bands, corresponding to chloride or iodide lattices. The strong band at 449 nm dominates the luminescence of these samples at low temperatures. Its kinetics have a complicated form and the decay time is in the interval from ns to ms. Quenched samples have a well-known luminescence spectrum caused by octahedral lead impurity centres in KCl single crystals. The kinetics, however, also indicate mixed chlorine and iodine coordination of lead in the investigated crystals.     

Negative luminescence from mid-wave infrared HgCdTe diode arrays

A self-referencing, optical modulation technique was used to measure the negative luminescence efficiencies of an array of mid-wave infrared HgCdTe photodiodes with cutoff wavelength 4.6 μm as a function of sample temperature. The internal efficiency at a wavelength of 4 μm was 93% at 295 K, and nearly independent of temperature in the 240–300 K range. This corresponds to an apparent temperature reduction >50 K at room temperature and >30 K at 240 K. Moreover, the reverse-bias saturation current density was only 0.13 A/cm². The measured transmission and emission spectra were simulated using empirical HgCdTe absorption formulas from the literature.     

Particle correlations in e + e − → W + W − events

Preliminary results are reported on the two-particle correlation function R(Q) in hadronic Z decays, fully hadronic WW decays, and mixed hadronic-leptonic WW decays using data collected by the DELPHI detector at LEP at energies between 189 and 206 GeV. Evidence for Bose-Einstein correlations was observed in all three cases. The event mixing technique was used to determine correlations between particles arisingfrom different W bosons in fully hadronic WW decays. An excess of like-sign particle pairs with low four-momentum difference in fully hadronic WW events is observed, consistent with the effect expected from correlations between identical particles from different W bosons.     

Relict Neutralinos in the Hot Universe

Russian Physics Journal -     

On the Efficiency of Nonchain Electric-Discharge HF (DF) Lasers

Russian Physics Journal -     

Nongravitational Fields and Space-Time Curvature

The problem of dimensionality of time is considered. The space-time curvature is shown to result not only from the presence of the gravitational field but also from a certain other field whose potential is a positive value.     

Magnetic Properties of Iron-Based Amorphous Metal Wires

It has been studied how the conditions of machining and the elastic tensile stresses affect the magnetic properties of amorphous metal wires of composition Fe₇₅Si₁₀B₁₅ produced by drawing from a melt. The magnetic characteristics of wires subjected to both thermal treatment and treatment with a continuous electric current of different magnitude have been investigated. The residual induction of wires is their magnetic parameter most sensitive to the conditions of treatment. The dependences of the residual induction on temperature and on the magnitude of the treating electric current are qualitatively similar. The greatest changes in residual induction are observed in the range of treating electric currents from 0.5 to 0.8 A, which can be associated with the processes of structural relaxation and crystallization occurring in the wires. The run of the dependence of the residual induction on the magnitude of tensile stresses is nonmonotonic in character and is determined by the level of internal hardening stresses of the test wires.     

The Kapitza Effect in Charge-Ordered Layered Crystals

It is shown that the Kapitza effect in charge-ordered layered crystals can be explained for the case of a parallelism of magnetic field and measuring current when the Landau quantization and its effect on the charge-carrier scattering are considered. There is a linear correlation between the magnetic field and longitudinal resistance under the assumption that the scattering of charge carriers by acoustic phonons is dominant, and the band-to-band transitions are suppressed. The relations for the Kapitza coefficient are derived for different degrees of electron gas degeneracy and different values of interaction resulting in layered charge ordering.