“Yennisei” space nuclear power system

March 1, 2000 is the 25th anniversary of the power start-up of a prototype of the “Yenisei” space nuclear power watem, which is to supply power to the spacecraft for a direct television roadcasting system, on the stand “1” at the Russian Science Center “Kurchatov Institute.” During the nuclear power tests, which continued for 5000 hours, the, subsequent finishing work, and a study of the state of individual components, it was demonstrated that the unit functions, properly under standard conditions. and the technology for preparing the unit for power tests and a procedure for starting up the unit and for performing power tests and the subsequent final adjustments together with an investigation of the critical component that determine the service life were developed. The results of the final adjustments and the investigations pointed the way to making the required improvements to the power-generating chanels in order to quarantee a service life of at least 15 years and then to increase it to 3 years at subsequent stages of the development work. The history of the development of the “Yenisei” nuclear power system is presented, the basic parameters and the results of comprehensive tests are described, and the international collaboration with the US is discussed. 7 figures, 1 table. Translated from Atomnaya énergiya, Vol. 88, No. 2, pp. 95–108, February, 2000.     

A crystal-chemical approach in the development of phosphate materials as environmentally safe chemical forms of utilization of spent Cs-containing ferrocyanide sorbents

Crystalline materials are developed as environmentally safe forms of chemical binding of components of spent cesium-containing ferrocyanide sorbents. Data on cationic compositions of ferrocyanides are summarized. Using structural-chemical modeling, compositions based on orthophosphates of framework structure, crystallizing in the structural type of langbeinite mineral, are chosen for the immobilization of cesium and ferrocyanide cations. The cationic composition includes cesium, some bivalent d elements, iron (molar ratio 2: 3: 2), and the cations added. The substances synthesized are characterized by X-ray phase analysis, DSC, and IR spectroscopy. Upon heat treatment of the samples for 5 h at 800°C, cesium does not pass to the gas phase. The leaching rate on the fifth day at 90°C in the dynamic mode was R = 3 × 10⁻⁵ g cm⁻² day⁻¹. The results of thermal and hydrolytic tests show that the crystalline forms chosen enhance the safety barrier for the incorporated cesium in the course of prolonged storage with isolation from the biosphere.     

Complex analysis and evaluation of the condition of reinforced-concrete components in power-generating structures

A procedure is proposed for analysis of reinforced-concrete slabs and shells.     

On the self-structuring of single-crystal silicon wafers under inductive heating in vacuum

The self-organized structuring of the surface of single-crystal silicon wafers under high-frequency annealing in a carbon-containing atmosphere is reported. The effect can be used to develop new maskless methods for the fabrication of structured materials for different functional purposes.     

Electrochemistry of galena oxidation as the basis for optimization of agent modes in flotation of polymetallic ores

The authors studied electrochemical oxidation of a galena electrode in aqueous alkaline solutions and established the limiting stage of galena oxidation and its kinetic characteristics. IR-spectroscopy analysis of oxidation products showed that complex chemical compounds were formed on the surface of the galena electrode under controllable oxidation.     

Effect of Inlet Window Deflectors on the Performance of a Natural-Draft Cooling Tower Subjected to Crosswinds

The effect of inlet window deflectors on the performance of a natural draft cooling tower subjected to a crosswind was studied numerically. Three patterns of the inlet window deflectors with different setting angles (62, 72, and 82 degrees) were tested under various crosswind velocities. The assumption of heat and mass transfer equivalence was adopted for simulation. A numerical model was developed and verified by comparison with experimental data. The simulations show that the 72-degree inlet window deflectors are efficient in a wide range of crosswind velocities. The effect of the number of deflectors was also investigated and the link between the velocity profile and the critical wind velocity was clarified. It was shown that the use of deflectors in the inlet window increases the thermal efficiency of a cooling tower up to 8.6% at wind velocities greater than 2 m/s and does not exhibit any effect at the wind velocities close to critical wind velocity. The investigation may be helpful in optimal design of natural draft and “hybrid” cooling towers.     

Synthesis of spatially ordered ensemble of Co nanocylinders in porous alumina matrix on surface of GaAs structures

A method for producing quasi-regular ensembles of Co nanocylinders with controllable height in anodic alumina pores on the surface of GaAs structures is improved. Alumina pores are filled by galvanic deposition of cobalt from CoCl₂ solution, which ensures uniform growth of Co in pores. It is established that, even at a small ratio of length of Co nanocylinders to their diameter l/d ≈ 2, the preferred direction of magnetic anisotropy coincides with the axis of nanocylinders.     

Normal and Superconducting Properties of Cuprates in Multielectron Theory

We consider the doping dependence of the normal and superconducting properties of La_2?x Sr _x CuO₄ in the low energy effective model based on the ab initio LDA+GTB calculations. We have found that two quantum phase transitions (QPT) of the Lifshitz type correspond well to the experimental phase diagram. For superconducting state, we have considered both magnetic and phonon mechanisms of pairing. Finally, we compare the true Fermi surface and the spectral intensity map seen in ARPES within a new norm conserving cluster perturbation theory (NC-CPT).     

The effect of heat flux on the rate of iron and copper corrosion product deposition in boilers

This publication is concerned with experimental data on the effect of heat flowrate (50–300 kW/m²) and iron concentration (10–40 µg/dm³) in water on the rate of corrosion-product deposition on a carbon steel surface under two (ammonia and metered-ammonia oxygenated) water-chemistry conditions.     

Electrical properties, photoconductivity, and photoluminescence of coarse-grained p-ZnTe

Electrical and photoelectric properties and also low-temperature photoluminescence of coarsegrained p-ZnTe with a resistivity of 3.3 × 10¹⁰Ω cm at 77 K have been studied. The coarse-grained ZnTe sample in the shape of a pipe was synthesized at 730°C from vapor phase in cocurrent flows of components. X-ray structure analysis showed that there are single-crystalline grains in both the [111] and [100] directions. In spite of nonequilibrium conditions of rapid crystallization, X-ray diffractometry measurements showed that the ZnTe crystallinity is good. The results of low-temperature photoluminescence confirm that there is an ordered distribution of impurities in the lattice. The set of impurities is limited to Cu, Ag, Li, and O. The photoconductivity and photoluminescence spectra indicate that there are poorly studied centers with levels deep m the band gap. In the regions with a low density of twins, there is observed a high quantum yield of photoluminescence, the absence of transitions related to complex defects, the presence of intrinsic emission with pronounced polaritonic structure, and manifestation of an ample structure of two-hole transitions that are absent in the crystals obtained under conditions of slow growth.