Electrical properties of p-type ZnGeP2 irradiated by H+ ions

The properties of p-type ZnGeP₂ [p₀=(5–10)·10¹⁰ cm^–3, ₀=(2–5)·10^–7 (·cm)^–1], irradiated with H⁺ ions [E=5 MeV, T_irr=300 K, D=(1·10¹²–1.7·10¹⁶) cm^–2] are studied. An increase in the resistivity (to gr_max - 5·10¹¹ ·cm) and subsequent reduction in for large currents of H⁺ ions ( - 9·10⁸ ·cm for D - 1.7·10¹⁶ cm^–2), is observed in irradiated crystals. The resistivity of irradiated p-type ZnGeP₂ is found to be very sensitive to hydrostatic pressure [(4–5)·10^–5 bar^–1]. The annealing of radiation defects in the temperature interval (20–600) °C is examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 91–93, October, 1991.     

Condensation of 2, 2 -dinitro-1, 3-peopanediol with hydrazineacetic acid esters

Conclusions The condensation of 2, 2-dinitro-1, 3-propanediol with pyrazineacetic acid esters leads to the formation of the esters of 4, 4-dinitropyrazolidine-2-acetic acid, which are spontaneously converted to the esters of 4-nitropyrazole-1-acetic acid.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2333–2334, October, 1972.     

An improved method for preparing α,ω-dinitroalkanes

Summary We have suggested an improved method for preparing , -dinitroalkanes which consists in the action of silver nitrite on , -dibromoalkanes in petrofeum ether medium with heating.     

η4-endo-(17α,21-dihydroxypregna-1,4-diene-3,11,20-trione)-(η5-cyclopentadienyl)rhodium(I)

η⁴-endo-(17α,21-dihydroxypregna-1,4-diene-3,11,20-trione)-(η⁵-cyclopentadienyl)rhodium(I) was synthesized by successive treatment of 17α,21-dihydroxypregna-1,4-diene-3,11,20-trione with [(C₂H₄)₂RhCl]₂ and CpT1 in a yield of 54%.¹H NMR studies demonstrated that coordination of the organometallic moiety occurs from the side opposite to the 19-CH₃ group. Upon coordination, ringA of the prednisone ligand is fixed to adopt a boat conformation, and the basicity of the 3-CO group increases substantially.     

New possibilities in nitration with a mixture of nitric acid and acetic anhydride

Summary A mixture of nitric acid and acetic anhydride with a nitric acid content of 80 moles per cent has a considerably more powerful nitrating action than a mixture with 35–50 moles per cent of nitric acid. It is desirable to use this mixture for the nitration of furans with low sensitivity to electrophilic attack.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 103–110, January, 1965     

A sesquiterpene lactone ofCyclachaena xanthifolia-anhydrocoronopilin

Chemistry of Natural Compounds - It has been shown that the dehydration of the sesquiterpene lactone coronopilin with SOCl2 forms Δ1(2)-anhydrocoronopilin. The configuration of the methyl...     

Numerical solution of direct kinetic problems

An algorithm is proposed to construct the righthand sides and the Jacobian matrix for a set of differential equations and a heat balance equation in terms of a given kinetic mechanism of a chemical reaction in a non-isothermal, constant-volume reactor. Its application is illustrated by the calculation of the dependence of the carbon monoxide explosion limit on the concentration of hydrogen added.

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Condensation of gem-dinitroalkanes with aliphatic aldehydes and amines

Summary Gem-dinitroalkanes condense readily with acetaldehyde, propionaldehyde, butyraldehyde, and amines. The use of these aldehydes instead of formaldehyde extends the field of application of the Mannich reaction with nitro compounds.     

Rate constant of free electron-hole recombination in thin cadmium sulfide films

The transient decay kinetics of electrons generated in thin cadmium sulfide films by short laser pulses was studied by the microwave photoconductivity method (9 and 36 GHz) at 295 K. The films were prepared by the pulverization method from thiocarbamide coordination compounds. At the high light intensity I ₀ > 10¹⁴ photon cm^–2 per pulse, the decay kinetics of photoelectrons corresponded to a reaction of the second order. Analysis of the kinetic data made it possible to determine the rate constant of recombination of free electrons and holes: k ₃ 2(±1)·10^–13 cm³ s^–1.     

Reaction of difluorocarbene with 2H-azirines: generation and transformations of strained azomethine ylides -- aziriniodifluoromethanides

The reaction of difluorocarbene with azirines affords a new type of azomethine ylides, viz., strained aziriniodifluoromethanides. 1,3-Dipolar cycloadditions of ylides derived from 2-unsubstituted 3-arylazirines to dimethyl acetylenedicarboxylate and aldehydes give derivatives of 2,2-difluoro-1-azabicyclo[3.1.0]hex-3-ene-3,4-dicarboxylic acids and 1,4-oxazin-3(4H)-ones, respectively. Ylides derived from 2-mono- and 2,2-disubstituted azirines undergo isomerization to 2-aza-1,3-diene derivatives. 2,2-Difluoro-1-azabicyclo[3.1.0]hex-3-enes are transformed into 2-fluoropyridine derivatives in high yields and react with amines to give 2,4-diamino-1-azabicyclo[3.1.0]hex-2-ene derivatives.