The effect of thermal treatment on the charge-carrier lifetime in nickel-doped silicon

This work is aimed at studying the electrophysical and recombination properties of slowly and rapidly cooled n-and p-type silicon doped by nickel during thermal treatment. It is shown that the changes in the lifetime in slowly and rapidly cooled n-Si<P, Ni> under isochronous thermal treatment depend on the “nickel + trace impurity” complexes. An increase in the lifetime observed in p-Si<B, Ni> as compared with the reference silicon is caused by the presence of a carrier-capture level. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 57–61, February, 2006.     

A study of the lifetime of impact-resistant polystyrene as a function of the action of external factors

The effect of temperature, oils, and domestic washing agents on the lifetime of type 475-K high-impact polystyrene has been studied. An intermittent character of the temperature-time dependence of strength has been observed. It has been discovered that household fats and cleaning media significantly affect the strength characteristics of high-impact polystyrene; the greatest action is exterted by the simultaneous action of an oily medium, temperature, and stress.V. I. Lenin Tadzhik State University, Dushanbe. Translated from Mekhanika Polimerov, No. 6, pp. 1121–1123, November–December, 1972.     

Berberis alkaloids 2’-N-methylberbamine fromBerberis oblonga

Summary A new alkaloid has been isolated from the roots ofBerberis oblonga. On the basis of spectral characteristics and chemical transformations, its structure has been determined as 2-N-methylberbamine.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. M. I. Kalinin Andizhan State Medical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 227–231, March–April, 1978.     

Mechanochemical Modification of 5-Nitro-8-hydroxyquinoline with Cellulose, Pectin, and β-Cyclodextrin

The physicochemical consequences of mechanical treatment of 5-nitro-8-hydroxyquinoline with natural polymers cellulose, pectin, and -cyclodextrin were studied in order to improve its properties. It was found that particle sizes of the medicinal compound in the agglomerated mechanical-composite materials increased. The particle-size increase of the medicinal compound was avoided by adding a third component differing from 5-nitro-8-hydroxyquinoline by the acid-base properties and containing calcium carbonate.     

High temperature gate control of quantum well spin memory

Time-resolved optical measurements in (110)-oriented GaAs/AlGaAs quantum wells show a tenfold increase of the spin-relaxation rate as a function of applied electric field from 20 to 80 kV cm(-1) at 170 K and indicate a similar variation at 300 K, in agreement with calculations based on the Rashba effect. Spin relaxation is almost field independent below 20 kV cm(-1) reflecting quantum well interface asymmetry. The results indicate the achievability of a voltage-gateable spin-memory time longer than 3 ns simultaneously with a high electron mobility.     

Synthetic analogs ofPeganum alkaloids. I. Synthesis of methoxy- and hydroxy-substituted deoxyvasicinones and deoxypeganines

6-Methoxy-, 7-methoxy-, and ′8-methoxydeoxyvasicinones have been synthesized by the reaction of substituted (3-methoxy-, 4-methoxy-, and 5-methoxy-) anthranilic acids with α-pyrrolidone. The demethylation of these compounds has given the corre-sponding hydroxy-substituted analogs of deoxyvasicinone, and the reduction of the products obtained with zinc in hydrochloric acid has given the hydroxy- and methoxy- analogs of deoxypeganine. 8-Hydrooxydeoxypeganine dimethyl-, ethyl-, and butylcarbamates have been obtained by the carbamoylation of 8-hydroxydeoxypeganine.