A mathematical model of electron and proton transport in oxygenic photosynthetic systems

Results of simulation of electron and proton transport in higher plant chloroplasts, taking into account the lateral heterogeneity of their lamellar system, were summarized. The existence of heterogeneous lateral profiles of pH inside thylakoids and in gaps between the thylakoids of grana was predicted. The basic kinetic relationships were simulated for photoinduced redox transformations of P₇₀₀, the primary electron donor for PS1. It was shown that, along with changes in pH inside thylakoids, an essential role in controlling the electron transport in chloroplasts can belong to alkalinization of the gap between thylakoids of grana, caused by deceleration of diffusion of hydrogen ions from the stroma to the PS2 complexes in thylakoids of grana.     

Modeling VHF emissivity of snow cover with account of its stratigraphy

In this paper, we discuss a model of emissivity of snow cover taking into account its structure. We assume that upward and downward radiation inside a snow layer are diffuse and apply the two-flux theory of Kubelka and Munk. Snow cover is modelled by a medium comprising discrete scatterers. In the case of dry snow, the scatterers are ice grains. Wet snow is modelled by a mixture of ice grains (with or without water envelopes) and water drops. We assume that the scatterers are spherical particles that have lognormal distribution over size. The brightness temperature of radio emission from snow cover on the soil is calculated using the data of glaciological measurements of physical parameters and microstructure of snow. Results of calculations are compared to measurements of the brightness temperature of radio emission from various types of snow covers. Space Research Institute of Russian Academy of Sciences, Moscow, Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 9, pp. 845–857, August 1999.     

Spin squeezing and quantum correlations

We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among the spinors in the coupled state.     

2,2,5,5-Tetramethyl-2,5-dihydropyrazine 1,4-dioxide —A new spin trap

Conclusions 2,2,5,5-Tetramethyl-2,5-dihyrodropyrazine 1,4-dioxide may be used as a spin trap for short-lived free radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1203–1204, May, 1985.     

Calculation of shrinkage stresses in fibrous composites with regular structure

The effect of the chemical and thermal shrinkage of the epoxy matrix on the structural residual stresses in plastics reinforced with anisotropic fibers has been investigated. The process of residual stress formation in all stages of a given curing regime is examined with reference to a regular triangular fiber distribution. The model of a hardening hypoviscoelastic medium [8] is used to describe the variation of the rheological properties of the matrix. The effect of the cooling rate on the residual stresses is investigated with reference to a single inclusion.Moscow Power Engineering Institute. Translated from Mekhanika Polimerov, No. 3, pp. 409–415, May–June, 1976.     

Temperature-time dependence of the adhesion strength for polymer — Polymer systems

The temperature — time dependence of the adhesion strength has been studied for polymer systems differing in the thermodynamic compatibility of the substrate and adhesive and in the rate of polymerization of the latter. The fracture-activation energies of these systems have been calculated. It is shown that the temperature — time dependence of the adhesion strength varies depending on whether chemical intermolecular forces are responsible for the strength of the joint.Perm Scientific-Research Institute of Polymer Materials. A. M. Gor'kii Ural State University. Translated from Mekhanika Polimerov, Vol. 4, No. 4, pp. 665–671, July–August, 1968.