The effect of food products on the endogenous formation of N-nitrosamines in rats

Data have been presented on carcinogenic N-nitrosoamines (NA) synthesis from precursors in the gastric juice and in the stomach of rats. It is shown that vegetable juices and milk produce an inhibitory effect with respect to NA synthesis in vitro and in vivo, however, food products with high content of fat intensify amine nitrosation.     

Study of a diffusion pump with thin-film evaporation of oil in the boiling tank

Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 5, pp. 5–6, May, 1990.     

Basic causes of deformation of buildings constructed on permaforst

Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 25–27, July–August, 1990.     

Preparation of Porous Ceramics from Nanocrystalline Zirconia and Their Microstructure

Data are presented on the compaction behavior of nanocrystalline yttria partially stabilized zirconia powder and the effects of compaction pressure, sintering temperature, and sintering time on the microstructure of the resultant ceramics. It is shown that even relatively low (50 MPa) compaction pressures lead to the disintegration of powder particles and aggregates. The compaction behavior of the powder points to changes in the densification mechanism: from quasi-liquid sliding of powder particles at the beginning of the process to the breakdown of large microstructural constituents at the end. In the initial stages of sintering, a robust skeleton forms, which plays a key role in determining the pore structure of the ceramic.     

Injection heterolaser based on an array of vertically aligned InGaAs quantum dots in a AlGaAs matrix

Arrays of vertically aligned InGaAs quantum dots in a AlGaAs matrix have been investigated. It is shown that increasing the band gap of the matrix material makes it possible to increase the localization energy of quantum dots relative to the edge of the matrix band, as well as the states of the wetting layer. The use of an injection laser as the active region makes it possible to decrease the thermal filling of higher-lying states, and thereby decrease the threshold current density to 63 A/cm² at room temperature. A model explaining the negative characteristic temperature section observed at low temperatures is proposed. The model is based on the assumption that a transition occurs from nonequilibrium to equilibrium filling of the states of the quantum dots. Fiz. Tekh. Poluprovodn. 31, 483–487 (April 1997)     

Modulation of a quantum well potential by a quantum-dot array

The possibility of locally varying the potential energy of the electrons and holes localized in a quantum well by a quantum-dot array deposited in the immediate vicinity of the quantum well is demonstrated. These changes in the potential energy are induced when a strain arises in the quantum-dot region. Fiz. Tekh. Poluprovodn. 31, 109–113 (January 1997)     

Test model of fast reactor with hexagonal lattice

Power-Physics Institute. Romanian Institute of Nuclear Power, Pitesh, Romania. Translated from Atomnaya Énergiya, Vol. 70, No. 6, pp. 403–405, June, 1991.