Избранные проблемы современной механики
The continuum model of radial mass transfer in plant roots we developed previously is used for processing the nonstationary experiments aimed at the determination of the root hydraulic conductivity. It is shown that in contrast to compartmental models our model allows to describe the observed shape of the relaxation curve and to obtain segments with different relaxation times. It is found that for correctly determining the hydraulic conductivity the data processing method should be modified. A method is also proposed for estimating the extracellular to intracellular conductivity ratio.
Let G be a reductive group and let ·G be its Langlands dual. We give an interpretation of the dynamical Weyl group of ·G de¯ned in  in terms of the geometry of the a±ne Grassmannian Gr of G. In this interpretation the dynamical parameters of  correspond to equivariant parameters with respect to certain natural torus acting on Gr. We also present a conjectural generalization of our results to the case of a±ne Kac-Moody groups.
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.