Crystal Structure of Bis -(2,2′-bipyridine-N,N′)-(dicyanamide-N)-copper(II) Tricyanomethanide. Electronic and Structural Parameters Describing the Shape of Coordination Polyhedra in Five-Coordinated Copper(II) Compounds

 The structure of the new compound [Cu(bpy)₂N(CN)₂]C(CN)₃ (6) is compared with thestructures of six copper(II) coordination compounds with phenanthroline or bipyridine ligands and N-donor pseudohalide anions: [Cu(phen)₂NCS]C(CN)₃ (1), [Cu(bpy)₂NCS]C(CN)₃ (2), [Cu(phen)₂NCS]ONC(CN)₂ (3), [Cu(phen)₂N(CN)₂]C(CN)₃ (4), [Cu(bpy)₂C(CN)₃]C(CN)₃ (5), and [Cu(bpy)₂NCO]C(CN)₃ (7). The Cu(II) atoms in all above compounds are five-coordinated with an N-donor atom of the pseudohalide anion located in the equatorial plane of a deformed trigonal bipyramid. The shape of the coordination polyhedra and the degree of trigonal bipyramidal distortion towards a tetragonal pyramid are discussed and described using one electronic and several structural criteria which are discussed and compared.     

Mössbauer study of magnetic anisotropy in electrochemically deposited Fe−Ni−P amorphous alloys

In a previous work [1], a large magnetic anisotropy was found as a preliminary result of the formation of electrochemically deposited Fe₉₃P₇ alloy. Mössbauer spectroscopy was used in order to get information about the magnetic anisotropy of electrochemically prepared Fe?P and Fe?Ni?P amorphous alloys. The Mössbauer spectra and the hyperfine field distributions of the samples show that Fe?Ni?P and Fe?P electrodeposited amorphous materials can be prepared in a reproducible way from a point of view of short range ordering which is strongly dependent on the chemical composition determined by preparation conditions. The average magnetization directions in the samples were determined from the transmission spectra measured in a normal and two tilted geometries by two types of evaluation methods [2,3]. We have found that the small spread model of the domain structure better describes the experimental results. The obtained data reflect the prevailing anomalous magnetization orientation in these electrodeposited amorphous alloys.     

Relaxation effects in the Mössbauer hyperfine structure of amorphous Fe70Co10B20 at 125°C

A new approach was attempted in following the irreversible relaxation effects in the hyperfine structure of amorphous Fe₇₀Co₁₀B₂₀. Room temperature transmission⁵⁷Fe Mössbauer spectra were measured in the course of interrupted isothermal annealing. For the data fitting, a model of pseudo-three-dimensional distribution of correlated hyperfine parameters was adopted and the corresponding spectrum modelled by a FFT-based procedure. In addition to commonly used hyperfine parameters, the second order quadrupole splitting was also considered. The time dependences of the average magnetic and the second order quadrupole splittings show two relaxation stages interpreted as the relief of quenched-in stresses and the free volume shrinking.     

On multiplicative maps

No abstract. November 15, 1999     

On pseudolinear functions

In this paper the structure of a smooth pseudolinear function is investigated and the general form of the gradient is given explicitly.     

Bradyon-luxon symmetry

We propose a spacetime scheme representing the union of the real and non-real spacetime as a possible geometrical framework for Caldirola’s idea, that the bradyonic motion can be regarded as a light-like motion in an additional extra space. The playground of all physical processes is the union space. However, the physical processes in union space are differently projected on the real and non-real spacetime. The waves linked with luxons in union space are projected on the real spacetime so that they propagate here always with the velocity of light. The waves linked with bradyons in union space are projected on the non-real spacetime so that they propagate here with the velocity of light. The wave linked with a bradyon in union space, which is projected on the real spacetime, is here described by the Schroedinger and Dirac equations. There is proposed a symmetry which demands that the physical world is in its law the same whether it is seen from real or non-real spacetime. We discuss some consequences of this symmetry in the theory of elementary particles.     

The modified k·p method to investigate polarization effects in nitride quantum-well devices

The modified k·p method (which includes both stress and polarization effects) has been used to investigate recombination phenomena in nitride quantum-well (QW) devices. Within their volumes, both spontaneous and piezoelectric polarization have been found to have an essential influence on carriers behaviour. In particular, as a result of the quantum-confined Stark effect, energy of radiation emitted within the AlGaN/GaN/AlGaN QW has been found to decrease rapidly with an increase in the AlN mole fraction of the barrier material, which means—with an increase in mechanical stresses at the GaN/AlGaN heterojunctions. It should also be stressed that screening of polarization effects induced by free carriers at least partly reduced the above stress influence. So both effects, polarization and its screening, are equally important in exact modelling of an operation of nitride QW devices.