Influence of the Rotation Frequency of a Disk Substrate Holder on the Crystal Structure Characteristics of MOCVD-Grown GaAs Layers

The influence of the rotation frequency of a disk substrate holder on the growth mechanism and crystal structure characteristics of MOCVD-grown GaAs layers has been studied. In the frequency range of 0–400 rpm, variations have been observed in the growth mechanism and rate, as well as of crystal perfection.     

Simulation of the superlinearity of dose characteristics of thermoluminescence of anion-defective aluminum oxide

The specific features revealed in the superlinearity of dose dependences of thermoluminescence of anion-defective aluminum oxide single crystals have been considered theoretically in terms of the model of an interactive trap system. The model explains the decrease in the degree of superlinearity at a low heating rate, as well as with an increase in the dose increment, the occupancy of deep traps, and the sensitivity of the crystals to radiation due to the increase in the concentration of luminescence centers. The obtained results indicate a widening of the possibilities of the model for interpreting experimental data in the investigation of the dose characteristics of thermoluminescence of the studied crystals.     

P–C Bond Cleavage by Hydroxyl Function during the Addition of Tris(2‐pyridyl)phosphine to Cyanopropargylic Alcohols in Water

The addition of tris(2‐pyridyl)phosphine to tertiary cyanopropargylic alсоhols in water (room temperature, no catalyst, 5 h) is accompanied by elimination of pyridine to give cyanoallyldipyridylphosphinates of E‐configuration in 60–73% yield, thus indicating the oxygen insertion of the hydroxyl group into the P C bond of the intermediate (Z)‐alkenyldipyridylphosphine oxide.     

Reaction of secondary phosphine chalcogenides with diallylamine

Diphenyl- or bis(2-phenylethyl)phosphine sulfides and -phosphine selenides react with diallylamine under radical initiation (UV or AIBN) to afford the corresponding diadducts and tetrahydropyrrolylmethyl phosphine chalcogenides. The yield and the ratio of the products depend on the structure of the starting secondary phosphine chalcogenides.     

Synthesis and biological activity of N-benzyl derivatives of cytisine

The reductive alkylation of cytisine by various aromatic aldehydes was studied. Preliminary pharmacological investigations of the synthesized compounds were performed. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 373–378, July–August, 2006.     

Fe-Mn-C alloys with anomalous volume of crystal lattice

The structure of intergranular interlayers in the 110G13L steel have been investigated. An increase in the lattice volume and occurrence of magnetization under dynamic load of samples quenched to austenite have been revealed.     

Reactions of azinium cations. 7. 13C NMR spectra and electron structure of neutral σ-adducts of 1,4-diazinium cations and methylate anion

The ¹³C NMR spectra have been recorded of a number of -adducts formed by pyrazinium, quinoxalinium, and pteridinium cations with methylate anion. The experimental data were compared with CNDO/2 calculations of adduct electron structure.For Communication 6, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1385–1391, October, 1987.