Electron-withdrawing effect of α-substituents in acyl nitrates on the polarization of the O–NO2 bond

1. Download high-res image (94KB)
2. Download full-size image

     

Interaction of deep impurities with radiation defects in n-Si at γ-irradiation

This work presents the results of research on peculiarities of radiation defect formation in single crystal n-Si, doped by deep level impurities (Cu, Ni, Ir, Rh, Pt and Au), at irradiation by γ-quanta of ⁶⁰Co. A property of γ-irradiation to create only vacancies and self-interstitial atoms is used to understand the nature of deep levels with participation of these impurities and primary elemental radiation defects. The role of covalence radii and diffusion coefficients in efficiency of radiation defect formation is discussed.     

Pulp depitching in the bisulfite pulping step

OS-20 nonionic surfactant produced in Russia was used as a depitching additive in bisulfite pulping. OS-20 ensures efficient depitching of bisulfite pulp produced from various kinds of wood (spruce, aspen, birch wood or their blends). The strongest decrease in the total and “harmful” pitch content in pulping in the presence of the surfactant was reached for spruce and aspen wood and for the blend of spruce and birch wood.     

Crystal structure simulation and estimation of the cocrystallization energy for [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine-4,6-dioxide with nitrobenzenes

Russian Chemical Bulletin - The structure of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine-4,6-dioxide (FTDO) cocrystals with nitrobenzenes at the ratio of components 1:1 was simulated using the...     

Effect of a mobile load on a nonlinearly compressed strip with a rigid foundation

The two-dimensional stationery problem of the effect of a mobile load on a nonlinear compressed strip with a rigid foundation is studied. The case of linear loading and unloading of the medium was analysed in [1, 2]. In this work, unlike [1, 2], the wave process is studied taking into account the nonlinear loading of the strip material, the effect of the inelastic properties of the medium on the distribution of kinematic parameters and stresses in it is studied, and the form of the surface of the front of the wave reflected from the rigid foundation is determined.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 129–133, May–June, 1986.     

Vibrational spectra and the structure of long-chain aliphatic compounds

Polymorphism and the structure of mesomorphous states of long-chain aliphatic compounds (LAC) have been studied by vibrational spectroscopy (theory, experiment) using calorimetry, polarizing microscopy (PM), and X-ray diffraction (XRD) analysis as auxiliary methods. LAC are represented by homologous series of alkyl- and alkoxybenzoic acids, alkylcyclohexanecarboxylic acids, their completely or partially fluoroalkyl-substituted analogs, and 4-cyano-4′-(n-alkoxy)biphenyls. The studies were performed at 77–500 K. IR absorption and Raman spectra were measured at 30–4000 cm⁻¹. The compounds are characterized by conformational polymorphism. The molecules and their H-complexes undergo structural rearrangements during phase and conformational transitions. In the course of the rearrangements, alkyl and fluoroalkyl radicals (AR and FAR) are twisted, and carboxyl groups are disordered. The rearrangements dictate the structure of mesophases, which are mostly formed of H-complexes consisting of dimers, monomers, and open associates. N. G. Chernyshevskii Saratov State University. Institute of Physics, Ukrainian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 36, No. 2, pp. 338–344, March–April, 1995. Translated by L. Smolina     

On the relaxation of volume and shear viscosities in vegetable oils

Longitudinal and shear ultrasonic measurements were performed on castor, tung, soyabean and cottonseed oils in the frequency ranges 50 kHz–30 MHz and 10–150 MHz using reverberation, pulse and impedance techniques respectively. In castor and tung oils relaxation spectra for both volume and shear viscosities are broad and identical in shape. In soyabean and cottonseed oils both volume and shear viscosities undergo single relaxation but the volume relaxation time is about 10 times larger than the shear. It is suggested that shear relaxation results from molecular orientation and volume relaxation from rearrangement of molecular packing.