Peculiarities of structure formation of epoxy-amine polymers upon curing of diglycidyl ester of diphenylolpropane with adamantane diamines

The peculiarities of structure formation of epoxy-amine polymers upon curing of diglycidyl ester of diphenylolpropane with adamantane diamines are discussed. It is shown that, at the initial stage of polycondensation, deceleration of the curing process takes place that is caused by glass transition of the polycondensation products. It is found that complete consumption of all functional groups is impossible without additional postcuring.     

A possible combinatorial point for the XYZ spin chain

We formulate and discuss several conjectures related to the ground state vectors of odd-length XYZ spin chains with periodic boundary conditions and a special choice of the Hamiltonian parameters. In particular, we argue for the validity of a sum rule for the vector components that in a sense describes the degree of antiferromagneticity of the chain.     

Image recording in doped crystals of lithium niobate

In lithium niobate crystals doped with iron, copper, rhodium, and ruthenium ions, the optical image recording is feasible when the illumination gradient is directed parallel to the polar axis of the crystal. Depending on the dopant type, the doping level, and external conditions (for instance, the recording time), the storage time of the image can reach 60 days. The effect of polarization of recording radiation on the contrast of the recorded image is investigated.     

<Emphasis Type="Italic">O</Emphasis>(1) loop model with different boundary conditions and symmetry classes of alternating-sign matrices

This work is a continuation of our recent paper where we discussed numerical evidence that the numbers of the states of the fully packed loop model with fixed pairing patterns coincide with the components of the ground state vector of the O(1) loop model with periodic boundary conditions and an even number of sites. We give two new conjectures related to different boundary conditions: we suggest and numerically verify that the numbers of the half-turn symmetric states of the fully packed loop model with fixed pairing patterns coincide with the components of the ground state vector of the O(1) loop model with periodic boundary conditions and an odd number of sites and that the corresponding numbers of the vertically symmetric states describe the case of open boundary conditions and an even number of sites.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 142, No. 2, pp. 284–292, February, 2005.     

Optical system aberration effect on the second harmonic generation

The results of observation of the aberration effect representation by the focusing optical system in the angular structure of the frequency-transformed radiation are presented. The experiments have been performed on lithium iodate crystals.     

Problems of adhesion strength in epoxy-allylic polymer-polymer systems

The main aspects of the problems associated with adhesion and adhesion strength, as well as the factors causing formation of boundary layers (BLs), are discussed. The results of studying the effect of various factors (the ratio between EA polymer components, the chemical structure of curing agents, and curing modes) on the formation of BLs and adhesion strength of adhesive substances are reported by the example of epoxy-allylic (EA) polymer-polymer systems are reported.     

Gyration Waves in Optical Crystals

The optical activity of crystals can be explained by energy transfer from radiation incident on the crystal into the radiation mode (gyration wave) propagating in the incident wave direction but having the polarization plane perpendicular to that of incident radiation.__________Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 6–10, January, 2005.