Spectral photoresistive effect of the field in CdS crystals at low temperatures

The influence of the surface electric field on the low-temperature (T=77 K) photoconductivity spectra of CdS crystals in the region of exciton and interband transitions is experimentally studied by the field-effect method. The photoconductivity spectra of a semiconductor are numerically calculated in the framework of a model allowing for the dependence of the surface recombination rate of nonequilibrium charge carriers on the surface electric field. It is demonstrated that the surface electric field plays a decisive role in the formation of the fine spectral structure associated with the excitons. A correlation between the type of fine structure and the surface bending of the energy bands is revealed. It is shown that the surface electric field can be evaluated from the shape of the low-temperature photoconductivity spectrum of the semiconductor.     

Polycrystalline material diagnostics based on the peak of polarization bremsstrahlung radiation propagation against the velocity of emitting electrons

We discuss the possibility of using an anomalous peak of polarization bremsstrahlung radiation from relativistic electrons for the diagnostics of polycrystalline materials.     

On the Applicability of the Relations of the Cubic Timoshenko-Type Theory of Shells to the Study of the Postcritical Behavior of Rods

The question of whether the nonlinear Timoshenko-type theory of shells can be applied to the study of the initial postcritical behavior of a rod under compression is considered. The Koiter asymptotic theory in the Budyanskii form is used. The exact solution of the problem is obtained and a formula for the coefficient of postcritical behavior allowing for the effect of lateral-shear strains is derived. It is shown that the expressions (specified to within cubic terms) for lateral-shear strains and curvature permit us to use the nonlinear theory of shells to analyze the initial supercritical behavior of rods     

Copper Tetra-4-Carboxyphthalocyanine as a Chemical Additive and Dye for Composites and Polycaproamide

Copper tetra-4-carboxyphthalocyanine was studied as a chemical additive and dye for a polymeric binder of fibrous composites and polycaproamide.     

Probability Characteristics of Passive-Tracer Clusters in a Two-Dimensional Turbulent Medium

We study the evolution of a passive-tracer cluster on the surface of a turbulent medium. Stochastic equations for geometric characteristics of the density distribution of a passive tracer are derived and analyzed. We show that the cluster can be localized in such a way that cluster particles can stay near one another for a long time not obeying the molecular-diffusion law. The conditions of existence of a localization phenomenon in the case of significant anisotropy of the cluster are found along with the probability distributions of geometric properties of the cluster.