Magnetic and specific heat properties of YFe3(BO3)4 and ErFe3(BO3)4
The present paper reports on the specific heat and magnetization of the YFe3(BO3)4 and ErFe3(BO3)4 single crystals. In both compounds, antiferromagnetic order of the iron spins evolves at TN = 38 K. The experimental data suggest that the magnetic moments are in the basal plane of the trigonal crystal for both compounds. In the magnetically ordered state the crystal is subdivided into three types of domains, the magnetic moments of the Fe3+ ions being aligned along the a axis within each domain. For ErFe3(BO3)4, two non-equivalent magnetic positions of the Er3+ ions in each domain are observed.
We present the thermodynamic properties and the magnetic phase diagram of Gd2BaNiO5 investigated by means of specific heat and magnetization measurements performed along the main crystallographic axes of the single crystal. Our data imply antiferromagnetic ordering at TN = 55 K and a spontaneous spin-reorientation transition at TSR = 24 K. Upon application of external magnetic fields, a spin-flop transition is observed at T < TSR in magnetic fields B || b-axis and at TSR < T < TN in magnetic fields B || a-axis. The magnetic phase diagram in Gd2BaNiO5 is established from these data. Considering Gd-Gd and Gd-Ni interactions allows estimating the magnetic contribution of the gadolinium subsystem to the magnetization and the specific heat. The analysis of the experimental data shows that the behavior of the nickel subsystem differs from that of a classical antiferromagnet.
The dynamics of a two-component Davydov-Scott (DS) soliton with a small mismatch of the initial location or velocity of the high-frequency (HF) component was investigated within the framework of the Zakharov-type system of two coupled equations for the HF and low-frequency (LF) fields. In this system, the HF field is described by the linear Schrödinger equation with the potential generated by the LF component varying in time and space. The LF component in this system is described by the Korteweg-de Vries equation with a term of quadratic influence of the HF field on the LF field. The frequency of the DS soliton`s component oscillation was found analytically using the balance equation. The perturbed DS soliton was shown to be stable. The analytical results were confirmed by numerical simulations.
Radiation conditions are described for various space regions, radiation-induced effects in spacecraft materials and equipment components are considered and information on theoretical, computational, and experimental methods for studying radiation effects are presented. The peculiarities of radiation effects on nanostructures and some problems related to modeling and radiation testing of such structures are considered.
This volume presents new results in the study and optimization of information transmission models in telecommunication networks using different approaches, mainly based on theiries of queueing systems and queueing networks .
The paper provides a number of proposed draft operational guidelines for technology measurement and includes a number of tentative technology definitions to be used for statistical purposes, principles for identification and classification of potentially growing technology areas, suggestions on the survey strategies and indicators. These are the key components of an internationally harmonized framework for collecting and interpreting technology data that would need to be further developed through a broader consultation process. A summary of definitions of technology already available in OECD manuals and the stocktaking results are provided in the Annex section.