Cross-relaxation and phonon bottleneck effects on magnetization dynamics in LiYF4:Ho3+

Frequency and dc magnetic field dependences of dynamic susceptibility in diluted paramagnets LiYF$_4$:Ho$^{3+}$ have been measured at liquid helium temperatures in the ac and dc magnetic fields parallel to the symmetry axis of a tetragonal crystal lattice. Experimental data are analyzed in the framework of microscopic theory of relaxation rates in the manifold of 24 electron-nuclear sublevels of the lowest non-Kramers doublet and the first excited singlet in the Ho$^{3+}$ ground multiplet $^5I_8$ split by the crystal field of S$_4$ symmetry. The one-phonon transition probabilities were computed using electron-phonon coupling constants calculated in the framework of exchange charge model and were checked by optical piezospectroscopic measurements. The specific features observed in field dependences of the in- and out-of-phase susceptibilities (humps and dips, respectively) at the crossings (anti-crossings) of the electron-nuclear sublevels are well reproduced by simulations when the phonon bottleneck effect and the cross-spin relaxation are taken into account

Electrical load forecasting

Some long-term design activities are based on electrical load forecasting. Forecasting errors result in the wrong decisions being made in the future. At present there are three widely used methods of forecasting: the method based on enlarged specific indexes (ESI), the econometric method and the self-sufficient method. All of these methods have their own disadvantages and errors in estimation. The main reasons for errors in areas such as objective reasoning, changes in production technology, the lack of reliable long-term forecasting for economy development and consumer infraction of load schedule are determined in this paper and an objective estimation for the forecasted error of different spheres of application is made. This work aims to determine a sphere of application for each of these methods and to develop a principal of combined application, so that they may decrease forecasting error. The purpose of this work consists of the creation of an electrical load forecasting method to obtain more reliable data for the different time periods and territory. A new method is presented, based on calculations carried out. Recommendations for all existing methods are given with reference to the calculations and the way that the combined application of several methods was introduced to increase the reliability of a forecast. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen

High energy inelastic electron hadron scattering, in peripheral kinematics. Sum rules for hadron form factors

Relations between differential cross section for inelastic scattering of electrons on hadrons and hadron form factors (sum rules) are derived on the basis of analytical properties of heavy photon forward Compton scattering on hadrons. Sum rules relating the slope of form-factors at zero momentum transfer and anomalous magnetic moments of hadrons with some integrals on photo-production on a hadrons is obtained as well. To provide the convergence of these integrals we construct differences of individual sum rules for different hadrons. Universal interaction of Pomeron with nucleons is assumed. We derive the explicit formulae for processes of electro-production on proton and light isobar nuclei. Sudakov's parametrization of momenta, for peripheral kinematics relevant here, is used. The light-cone form of differential cross sections is also discussed. The accuracy of sum rules estimated in frames of point-like hadrons and it is shown to be at the level of precision achievable by experiments. Suggestions and predictions for future experiments are also given.Comment: 18 pages, 5 figure

In situ X-ray diffraction investigation of nitride coatings at high-temperature oxidation

Structural and phase researches of the multicomponent nanocrystalline coatings synthesized by plasma-assisted vacuum arc method at high-temperature influence by method of X-ray diffraction with the use of synchrotron radiation in situ have been carried out. The main features of these coatings are the superhardness (39 - 45 GPa) and nanocrystalline structure (5 - 20 nm). The analysis of results of structural and phase researches, physical and mechanical characteristics after oxidation of multicomponent nitride coatings at high-temperature heating in open air is presented

The Transient Ultra-luminous X-ray Source, ULX-4, in M51

We present the results of a temporal and spectral analysis of the transient source ULX-4 in the galaxy M51. The data used were drawn from Chandra, XMM-Newton and Swift-XRT archives, spanning the years 2000-2019. The X-ray flux of the source is seen to vary by two orders of magnitudes within a month but a short-term variability was not observed over the time intervals of 100-2000 second in the 0.3-10 keV energy band. We find some evidence for the existence of bi-modality feature in the flux distribution of ULX-4. We identified two optical sources as possible counterparts within an error radius of 0."18 at 95% confidence level for ULX-4 based on the archival HST/ACS and HST/WFC3 data. Blackbody fits of the spectral energy distributions (SEDs) indicate the spectral type to be B-type stars. One of these counterparts exhibits a low-amplitude optical periodicity of 264 days in the F606W filter; if we assume this apparent periodicity is associated with the orbital motion of the donor, then it is more likely that the donor is a red supergiant satisfying the long periodicity and accretion via Roche-lobe overflow. Consequently, the SED would then have to be interpreted as a superposition of emissions from a cold donor and a hot flow component, most likely from an accretion disk. If, on the other hand, the periodicity is super orbital in nature i.e., due to possible interactions of the compact object with a circumstellar disk, the donor could then be a Be/X star hosting a neutron star.Comment: Accepted for publication in MNRAS. 16 pages, 12 figures, 6 table