Pairwise nonlinear interactions of tollmien-schlichting waves in flows of the boundary-layer type

For a flow of the boundary-layer type, the method of a phase plane is used to investigate the joint evolution of a pair of Tollmien–Schlichting waves as a function of the R numbers and the frequencies.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 33–37, March–April, 1977.     

A note on the rates of convergence for weighted sums of ρ * -mixing random variables

We discuss the rates of convergence for weighted sums of ρ ^? -mixing random variables. We solve an open problem posed by Sung [S.H. Sung, On the strong convergence for weighted sums of ρ ^? -mixing random variables, Stat. Pap., 54:773–781, 2013]. In addition, the two obtained lemmas in this paper improve the corresponding ones of Sung in the above-mentioned paper and [S.H. Sung, On the strong convergence for weighted sums of random variables, Stat. Pap., 52:447–454, 2011].     

Controllable growth of individual, uniform carbon nanotubes by thermal chemical vapor deposition

We report on the controllable growth of individual, uniform carbon nanotubes using thermal chemical vapor deposition (CVD). We performed a detailed study of the various factors influencing the growth of single nanotubes. In particular, we investigated the role played by catalyst layer thickness, catalyst dot size, deposition temperature, and gas source pressure on the growth process of straight, single nanotubes. Straight, individual nanotubes with uniform diameter can be obtained by decomposition of 0.1 mbar of acetylene at a temperature of 800 °C over a 5 nm thick nickel film that is patterned into square dots with dimensions below 500 nm. We compare the performance of thermal CVD and of plasma enhanced CVD for growing individual nanotubes.     

Dichroism in transmission of light by an array of self-assembled GaAs quantum wires on a nanofaceted A(311) surface

Dichroism in the transmission of light (the dependence of the transmittance on the direction of polarization of light) is revealed in corrugated GaAs/AlAs superlattices grown on a nanofaceted A(311) surface. It is assumed that the observed effect is associated with the structural anisotropy, i.e., with the formation of an array of GaAs quantum wires. This inference is confirmed by high-resolution electron microscopy. The GaAs/AlAs superlattices containing quantum wires also exhibit polarization anisotropy of the photoluminescence observed in the yellow-red spectral range.     

Creep of polyolefins

Conclusions 1. In their deformation properties the polyolefins studied are substances of a single class even under creep conditions. The principal factor which distinguishes the behavior of one polyolefin from another is the critical values of the specific volume V_o. At an identical value of V-V_o (at corresponding temperatures) the creep process is identical in polyolefins of different density.2. Change in the specific volume of polyolefins takes place upon the action, not only of temperature, but also of stress, and also as a result of thermooxidative processes, which exert a strong effect on the creep of these substances.A report presented at the Third All-Union Conference on Polymer Mechanics, Riga, 1976.M. I. Kalinin Leningrad Polytechnic Institute. Translated from Mekhanika Polymerov, No. 1, pp. 22–26, January–February, 1978.     

Saturated vapor pressure in the thallium-cadmium system

Component vapor pressures in the thallium-cadmium system determined by the method of boiling points (isothermal variant) and the flow method were used to calculate the thermodynamic characteristics of the vapor and condensed phases in the region of the existence of liquid solutions. The temperature-concentration dependences of the thermodynamic values were determined. The phase diagram was augmented by liquid-vapor phase transitions at atmospheric pressure and in a vacuum (100 and 10 Pa) with the determination of the boundaries for the coexistence region of the liquid and vapor phases.     

Melt–vapor phase transition in the lead–selenium system at atmospheric and low pressure

The boiling temperature and the corresponding vapor phase composition in the existence domain of liquid solutions were calculated from the partial pressures of saturated vapor of the components and lead selenide over liquid melts in the lead–selenium system. The phase diagram was complemented with the liquid–vapor phase transition at atmospheric pressure and in vacuum of 100 Pa, which allowed us to judge the behavior of the components during the distillation separation.     

Structure of С@Al<Subscript>2</Subscript>O by multinuclear solid-state NMR spectroscopy

The ²⁷Al, ¹H MAS NMR method is used to study initial nanosized metastable aluminum oxides of a pseudoboehmite series (γ- and δ-Al₂O₃) after being coated with graphene (С@Al₂O₃) and annealed in the air (С@Al₂O₃-Т). It is demonstrated that aluminum nanoparticles coated with graphene and annealed at high temperatures (to 750°C for γ and 1180°C for δ) preserve their phase composition but differ from initial oxides by a very low concentration of defects (ОН groups). After the annealing of the graphene coating the hydroxyl cover of oxides is reduced, however, the set of ОН groups differs greatly from that of the initial oxides. Only one type of terminal ОН groups with a ~0.2 ppm shift and one type of bridging μ²-ОН groups with a 1.8 ppm shift for γ-Al₂O₃ from OH-μ²-AlVAl_n and 2.1 ppm for δ-Al₂O₃ OH-μ²-AlIVAl_n are observed. The data obtained make it possible to characterize in detail the δ-Al₂O₃ pure phase.