Energy and Acid-Base Characteristics of the Surface of Nitramine Fillers for Polymeric Composites

Single crystals of nitramine fillers for special-purpose polymeric composites are characterized by the surface energy and its constituents and also by the acidity of their surface.     

Numerical simulation of achromatic deflecting systems

A deflecting system formed by two parallel-plate capacitors on opposite sides of an optoelectronic element that alters the energy of a beam of charged particles, is calculated numerically. The conditions for correcting the chromatic beam spreading in the plane of the target are found. Good agreement with the results of an approximate analytical calculation is demonstrated. Zh. Tekh. Fiz. 67, 86–88 (December 1997)     

Reactions of cyclammonium cations

The reaction of 1,2-diaminopyridinium salts with -dicarbonyl compounds or -halogeno ketones forms pyrido[1,2-b][1,2,4]triazinium salts. A methyl group present in position 2 of one of these salts condenses with aldehydes, giving styryl derivatives and reacts with orthoesters to give cyanines.For Communication XXII, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1266–1270, September, 1973.     

Dielectric properties of liquid crystals of the cyano derivative compounds with different fragments in the molecular core

This paper reports on the results of investigations into the influence of variations in the chemical composition of the aromatic core of cyano-containing molecules of liquid crystals on their dielectric properties in the frequency range 1–2000 MHz. It is shown that the dispersion of the longitudinal permittivity is adequately described by the sum of two Debye processes with different weighting factors and relaxation times. The frequency dependence of the transverse permittivity is well approximated by the Debye process with a continuous distribution of relaxation times in a specified range. It is established that the replacement of one benzene ring in the biphenyl core of the 5CB liquid-crystal molecule by a cyclohexane (or bicyclooctane) fragment leads to a considerable decrease in both relaxation times for the longitudinal permittivity, a change in the low-frequency limit of the relaxation time range for the transverse permittivity, and the evolution of the frequency dependence of the dielectric anisotropy.     

Experimental value of G A/GV from a measurement of both P-odd correlations in free-neutron decay

A new experimental value of the fundamental weak-interaction parameter λ=G _A/G_V (?1.2686±0.0046) is obtained for the first time by an original method that consists in measuring both P-odd correlations in free-neutron decay.     

Dissociation of alkane ionized molecules

The subject of investigation is the fragmentation of variously charged molecular ions arising in col-lisions of several kiloelectronvolt H⁺, He²⁺, and Ar⁶⁺ ions with molecules of the simplest alkanes (from methane to butane). Using the method of time-of-flight mass spectrometry, the formation cross sections of dissociation-induced fragment ions are measured. The dissociation takes place when an incident ion captures an electron from a methane, ethane, or propane molecule. The role of additional ionization of the molecule, which accompanies the electron capture by the incident ion, is elucidated. The kinetic energy spectrum for protons resulting from the fragmentation of multiply charged alkane ions is determined. The most plausible kinetic energies of protons depending on the degree of ionization and molecule size fall into the range 1–25 eV. It is shown that, when the molecule loses several electrons, the kinetic energies of protons are governed by Coulomb interaction between all fragment ions and are determined by their flying apart from the relative spatial arrangement of corresponding atoms in a parent molecule.     

Visual investigation of the intermediate state in the region of metamagnetic phase transition in ErFeO3

We carried out the first observation of the intermediate state (IS) in the region of metamagnetic phase transition (MPT) in ErFeO₃: an external magnetic field H∥c (H=0–4 kOe), the temperature range 2.15–1.6 K. The ranges of the IS existence and the domain structure (DS) features were determined. Likely mechanisms of the IS thermodynamic stabilization and conditions for its visualization in ErFeO₃-plates with various crystallographic orientations were analyzed. The thermodynamic model of IS was offered: the intermediate state was stabilized by the mechanical stress that accompanies MPT. Excellent agreement with experiment was achieved.     

A new method for the synthesis of the marine alkaloid fascaplysin

A new method for the synthesis of the marine alkaloid fascaplysin has been developed via a simple and practical approach to pyrido[1,2-a:3,4-b′]diindole ring system formation. Conversion of the marine alkaloid homofascaplysin C into fascaplysin is also described.