Thermodesorption of samarium from oxidized tungsten surface

Thermodesorption of samarium (Sm) atoms and samarium oxide (SmO) molecules from samarium films deposited in vacuum onto tungsten substrates covered with thin (<1 nm thick) layers of tungsten oxides has been studied. It is established that samarium reduces tungsten from its oxides. The parameters of Sm and SmO desorption from an oxidized tungsten surface are determined.     

Certain regularities of the kinetics of drying of moist materials

A method for calculating the kinetics of drying under the conditions of continuous variation in the Rehbinder number in the period of decreasing drying rate is considered. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 80, No. 4, pp. 143–146, July–August, 2007.     

Forming n-p junctions based on p-CdHgTe with low charge carrier density

The first results on the formation of n ⁺-p photodiodes with a long-wavelength boundary at λ_0.5 = 10.6 μm based on p-CdHgTe epilayers with a hole density of 3.3 × 10¹⁴ cm^?3 are presented. The CdHgTe layers were obtained by molecular beam epitaxy and exhibited p-type conduction in the as-grown state. The hole density and mobility were determined by means of the mobility spectrum technique. The photodiode structures were prepared by B⁺ ion implantation into as-grown p-CdHgTe epilayers without additional annealing. The R ₀ A product for the n ⁺-p photodiodes obtained is about 20 Θ cm² at 77 K.     

Reflection of electrons during tunneling and an intersubband polaron in the 2D electron system of a delta-layer in GaAs

Al-δ-GaAs structures are studied where tunneling to one or more subbands of the 2D electron system of a near-surface delta-doped layer is observed. Reflection of electrons at the threshold of the emission of an LO-phonon is observed. This phenomenon occurs when a new subband is involved in the tunneling process and when intersubband transitions of the electrons in a 2D-system with the emission of an LO-phonon are added to the inelastic tunneling within a single subband. It is shown that, under the conditions of an intersubband polaron resonance, the reflection processes dominate during tunneling into the delta-layer. If, however, tunneling from the delta-layer occurs, the reflection processes are observed when two subbands are occupied.     

Assessment of the adequacy of a mathematical model for the Fischer-Tropsch synthesis in a fixed-bed tube reactor with a cobalt catalyst

The adequacy of a model developed for the synthesis of hydrocarbons from CO and H₂ was assessed. It was found that the results calculated based on this model correspond to experimentally obtained data with a high degree of accuracy (the squared coefficient of correlation was higher than 0.97).     

Using biochemically purified water at coke plants

The use of biochemically purified water in place of industrial-grade water for the exhaust-gas scrubbers in the drying department of the coal-enrichment shop and for irrigation of the cyclone washers in the coke shops at OAO ZSMK is considered. It is found that biochemically purified water may be used for 100% of the water needs in coke production. Using biochemically purified water in the dust-trapping equipment, the coaland coke-dust content of the atmospheric emissions may be reduced by 24.5%. Additional purification of wastewater by adsorption on coke and coal dust is possible.     

Diesel fuel oxidation in storage

Diesel fuel should satisfy the European standards of quality even after long-term storage. The oxidation of diesel fuel, factors affecting this process, and their interaction mechanisms were studied in this work. Based on the results, conditions for the long-term storage of diesel fuel, including the type of storage tanks, can be determined.     

Effects of initial powder vibrogrinding on the properties of AlN - BN composites

A study has been made on the effects of initial vibroground powders with various grain sizes on the properties of AlN - BN composites. As the specific surface of these powders increases, so do the density, mechanical strength, and thermal resistance of the composites.     

Temperature dependence of the effective coefficient of Auger recombination in 1.3 μm InAs/GaAs QD lasers

Semiconductor laser heterostructures containing five and ten sheets of InAs/GaAs QDs on GaAs substrates, with an emission wavelength of ～1.3 μm, have been studied. Dependences of the nonradiative lifetime and effective Auger coefficient in QDs are obtained from an analysis of temperature and current dependences of the efficiency of spontaneous radiative recombination. The zero-threshold Auger recombination channel in QDs is shown to dominate at low (below 200 K) temperature, whereas at higher temperatures the quasithreshold channel becomes dominant. The effective 3D Auger coefficient is estimated in the approximation of a spherical QD, and a good agreement with the experimental data is obtained.