[en] A novel mechanism of electron-nuclear cross relaxation due to nuclear spin-spin flips is proposed. Equations are derived which relate the polarization of spin packets in a nonuniformly broadened EPR line with the inverse temperature of the nuclear dipole-dipole pool (NDDP). A method is described for identification of the mechanism with is based on the variation of the EPR line shape cooling of the NDDP

[en] Frequency oscillations are reported in the time-resolved ESR spectra from radicals produced by flash photolysis and shown to be consistent with theoretical predictions. They are manifest as additional peaks in the ESR spectra obtained at short times after the flash and could easily be misinterpreted as due to hyperfine coupling. Methods for their suppression are suggested. Resolution limitation at periods <= μs after the flash is also discussed. (orig.)

[en] An analysis of the effect of B₁ inhomogeneity on spin density and T₁ contrasted images is here given. Distorsions both in saturation recovery and inversion recovery sequences are found. The impact of these distorsion on in vivo spectroscopy, where quantitative data are required, is also discussed. In general, these aspects are found to be reduced at shorter-time parameters of the pulse sequences

No abstract available

[en] The basic principles of NMR ad NMR imaging are explained. Contrast devices in NMR images like spin-echo with enhanced T₂ and partial saturation images with enhanced T₁ contrast, are treated briefly. Techniques for improving image quality, spatial resolution and decreasing measuring time are discussed briefly. 6 refs.; 9 figs

No abstract available

[en] The basic principles that must be known to interpret NMR images, are exposed. After an analysis of the fundamental parameters (T1 and T2 relaxation time particularly), the main elements necessary to analyse a Spin Echo image are presented

[en] The author traces the encounter of μSR physicists with the Kubo-Toyabe theory and the subsequent development of zero-field μSR by mutual communication between experiment and theory

[en] The massless field perturbations of the accelerating Minkowski and Schwarzschild spacetimes are studied. The results are extended to the propagation of the Proca field in Rindler spacetime. We examine critically the possibility of existence of a general spin-acceleration coupling in complete analogy with the well-known spin-rotation coupling. We argue that such a direct coupling between spin and linear acceleration does not exist

[en] The analysis of the effects identified in the area of the EPR transitions resonance positions coincidence in the exchange-bound dimers of copper, iron high-spin centers in the lithium germanate and the Tl²⁺ noncentral ions in the potassium sulfate, is carried out. The study is accomplished on the basis of the model of the relaxation averaging of the part of the heterogeneously widened initial lines. It is shown that additional signals observed in these materials in the area of coincidence of the resonance positions of two transitions, may be qualitatively explained by averaging the part of the spin packages of the initial transitions