X-ray spectral and diffraction studies of germanides of iron-group metals in the amorphous and crystalline states

This article examines results of x-ray emission spectroscopy and x-ray diffractometry of amorphous and crystalline layers of certain germanides of iron-group transition metals. Combined analysis of the K- and L-bands of Me and Ge in Me₂ (Fe, Co, Ni)Ge and data from model interpretation of radial distribution functions of atoms in amorphous layers are used to make conclusions on the character of the chemical bond and the structure of the short-range order in the materials studied. It was established that there is no significant change in the character of the chemical bond in germanides Me₂(Fe, Co, Ni)Ge in the transition from the crystalline to the amorphous state. It was also found that short-range order in the investigated amorphous layers can be described by a complex poly-structural atom distribution, i.e. it is characterized by a complex, microscopically nonuniform model of the type Me₂Ge+Me.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 39–43, January, 1986.     

Gallium arsenide avalanche-type S-diode based on a n+-π-ν-n structure

The results are presented of an investigation of the electrical characteristics of avalanche S-diodes based on a new type of structure (⁺---n), which is obtained by diffusing iron in GaAs with n = 1.10¹⁷ cm^–3. The diodes have regions of S-type negative differential resistance (NDR), for both bias polarities and have a number of other features by comparison with diodes based on the --n structures with fused contacts. We discuss the mechanism for the formation of the NDR region of the voltage-current characteristics of the diode.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 54–58, April, 1986.     

Separation and determination of volatile compounds in synthetic wine samples by gas chromatography using UV-visible molecular absorption spectrometry as detector

This paper shows the separation and determination of eight compounds containing the OH group (ethanol, pentanol, 3-methyl-1-butanol, hexanol, phenol, benzyl-alcohol, phenylethanol and geraniol) in synthetic wine by gas chromatography using UV-Vis molecular absorption spectrometry as detection system. All the parameters affecting the separation and determination were optimised using some methods of experiment design. The analytical characteristics of each compound were calculated and detection limits ranging from 2.3 to 74 mg l(-1) have been obtained.     

Parametric Excitation of the Electron-Acoustic Wave in a Multiply Ionized Plasma

Parametric excitation of the electron-acoustic wave (EAW) has been analysed using a hydrodynamical model. The plasma has been assumed to consist of multiply charged ions. The ratio (α) of the hotter ion concentration to that of the electrons is a sensitive parameter. The condition for the occurrence of the EAW is well satisfied for the smaller values of α. The growth rate of the instability gets enhanced by increasing α and the charge state of the hotter ions. The values of α can be varied within short range only.     

Polyene chains in molecular electronics

Current ideas of soliton switching as a possible route towards molecular electronics are reviewed. The relation between photoinduced dipole moments in dye molecules and soliton motion is pointed out. Derivates of -carotene are presented as candidates for components of molecular electronic devices.Dedicated to K. Dransfeld on the occasion of his 60th birthday     

Synthesis in the 2-mercaptobenzothiazole series

The reduction of some dihydrothiazolobenzothiazolium salts with sodium borohydride may take place in two directions: with the formation of thiazolidino[2, 3-b]benzathiazolines and with the cleavage of the C-S bond to give N-(-mercaptoethyl)benzothiazolines. The behavior of thiazolidino[2, 3-b]benzothiazoline under the conditions of acid and alkaline hydrolysis has been studied.For communication VI, see [1].     

2.6 Foods

Abstracts2 Particular products and fields of application

2.6 Foods     

THE PHOTOSENSITIZED OXIDATION OF SULPHIDES

Abstract— The rates of photosensitized oxidation of a number of sulphides were determined under standard conditions in 1, 1, 2,2-tetrachloroethane and in methanol. It was found that the ratio of the rates of reaction in the two solvents was not constant for different sulphides and that t -butyl sulphide does not react in methanol. It is inferred that the presence of an H atom in the α position is essential for reaction in polar solvents and an appropriate mechanism is suggested. The results indicate that reaction in chlorinated solvents may take place by a different mechanism which possibly involves H-abstraction by triplet sensitizer.     

Spin-spin coupling of77Se and31P nuclei in cyclic organophosphorous compounds

We have established that direct phosphorus-selenium spin-spin coupling constants in cyclic compounds with P=Se exocyclic and P-C endocyclic bonds are found in the range¹J_PSe=–708 to –859 Hz; in this case, it is greater for the axial orientation of P=Se than for the equatorial orientation.Deceased.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 776–780, April, 1990.