Glass forming ability and the electrical properties of semiconducting AsxTe1−x glasses

In the binary system of As-Te semiconducting glasses the glass forming ability is evaluated using the DTA data and the conditions of glass formation are discussed. A comparison of the thermophysical parameters with the electrical activation energy is made and the linear dependence between the atomization enthalpy and the activation energy is discussed.     

External inversion,internal inversion,and reflection invariance

Having in mind that physical systems have different levels of structure we develop the concept of external, internal and total improper Lorentz transformation (space inversion and time reversal). A particle obtained from the ordinary one by the application of internal space inversion or time reversal is generally a different particle. From this point of view the intrinsic parity of a nuclear particle (elementary particle) is in fact the external intrinsic parity, if we take into account the internal structure of a particle. We show that non-conservation of the external parity does not necessarily imply noninvariance of nature under space inversion. The conventional theory of beta-decay can be corrected by including the internal degrees of freedom to become invariant under total space inversion, though not under the external one.     

Kinetics of the fluorescence of poly(N-vinylcarbazole) and poly(N-vinylcarbazole) with 2,4,7-trinitrofluorenone in the solid state

The fluorescence decay time measurements by the stroboscopic method have been made on films of amorphous poly(N-vinylcarbazole) (PVCA) and PVCA doped with 2,4,7-trinitrofluorenone (TNF). The obtained lifetimes of two excimer species have at 77 K and at 300 K values of about 43 ns and 9 ns, which are similar to other measurements. The kinetics of excimer fluorescence and energy transfer in PVCA films are described by a simple model of the Stern-Volmer type. It assumes the fast migration of localized singlet excitons and their trapping in two species of excimer traps.We propose a modified kinetic model for films of PVCA with TNF. In this model we assume besides the exciton migration and trapping on excimer and impurity traps also the direct energy transfer from two excimer species to charge transfer complexes of PVCA with TNF by the Förster dipole-dipole mechanism. The estimated critical distance of this transfer are about 10 Å.     

Continuum eigenmodes of an inhomogeneous plasma

The van Kampen-Case treatment of the linearized Vlasov equation is generalized to cases of non-uniform plasmas in non-uniform equilibrium fields. This is done by transforming the Vlasov operator into the representation of the eigenfunctions of the streaming operator. The Vlasov operator is thus reduced to the form of a multiplication operator perturbed by an integral operator so that the continuum eigenfunctions may be constructed by adapting a method originally devised in neutron transport theory. The calculation leads to solving a non-singular Fredholm-type integral equation. Various kinds of degeneracy of the continuous spectrum are discussed and an example is given.Nademlýnská 600, Praha 9, Czechoslovakia.     

Some properties of ionization waves of varietyR in a neon glow discharge

The parameters of ther-ionization waves in a neon discharge were measured at two neutral gas temperatures (298°K and 77°K). The experimental results of the measurements of the artificially excitedr-ionization waves over the region of the homogeneous positive column in discharge tubes with different radius (from 0·5 cm to 1·2 cm) are reported. The results are arranged as simple functions of pressure, electric field and discharge tube radius. The product of the wave-length and the electric field and the ratio of the group and phase velocities are independent of the temperature. The temperature changes of the dependences of the frequency and phase and group velocities are connected with the temperature changes of the atomic ion life-time in neon discharge. The validity of the dependences for wave parameters is confined to the artificially excited waves in a homogeneous positive column.Authors express their gratitude to M. Novák, L. Láska, K. Rohlena and V. Krejí for helpful discussions and valuable remarks on this work.