Hydrophobicity and thermal stability of fluorinated pentaerythritol esters

Wetting angles and limits of thermal stability of esters derived from pentaerythritol and perfluoro-, ω-chloropolyfluoro-, and perfluoropolyethercarboxylic acids were studied.     

On the moment characteristics of distributions

We study different moment characteristics of (mostly discrete) distributions: general, central, binomial, and factorial moments, and also ordinary and factorial semi-invariants. We establish the relations that connect various kinds of “moments” of arbitrary order, and we derive recursion formulas. Translated fromMetody Matematicheskogo Modelirovaniya, pp. 34–41, 1998.     

Determination of the thermal stresses in anisotropic shells of revolution

Using the relations of the improved model of layered anisotropic shells based on the straight line assumption taking account of the thermal compression over the thickness we obtain a resolvent system of equations for shells whose properties depend on temperature. We carry out a study of the stresses in a two-layer cylindrical shell formed by winding as a function of the winding angle. Translated fromMatematicheskie Metody i Fiziko-Mekhanicheskie Polya, Issue 35, 1992, pp. 82–85.     

Stationary and periodic solutions of the operator Riccati equation under a random perturbation

Sufficient conditions are presented for the existence of stationary and periodic solutions of the operator Riccati equation under a random perturbation.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 45, No. 5, pp. 609–615, May, 1993.     

Finite-element calculation of the influence of interdiffusion on eigenstates in a GaAs/Al x Ga1-x As single-quantum-well structure

The influence of interdiffusion on eigenstates in an interdiffusion-induced GaAs/Al_xGa_1-xAs single-quantum-well structure is analysed numerically by the finite element method. In this approach, the confinement potential profile of the interdiffused quantum well structure is nonlinear and is modelled by an error function and, in particular, the nature of the effective mass of an electron is considered. The results show that the number of eigenstates and energy levels varies with the extent of the interdiffusion. Numerical results for the quasi-bound states in the quantum well structure with an applied electric field are also presented.     

Varieties whose countable embeddability skeletons are semilattices

Translated fromAlgebra i Logika, Vol. 32, No. 3, pp. 288–307, May–June, 1993.     

On some methods of descent over groups of variables

Translated fromIssledovaniya po Prikladnoi Matematike, No. 19, 1992, pp. 24–33.     

Micron-image transfer system with brightness amplifier in gold-vapor laser

A gas-discharge gold-vapor laser on self-terminating transitions with operating wavelength λ=312.2 nm has been used to develop a highly efficient system for image transfer. An optical scheme and all its parameters have been chosen optimal for image quality. It has been found both theoretically and experimentally that the best results on micron-structure image transfer are obtained with 2–5-times image reduction. Various types of masks have been used. A 1-µm structure has been resolved due to the choice of optimal exposure time of 10 ms under a period of pulse repetition (0.6 – 0.8) ms; in this case, the minimal fringe dimension was ≈2 µm with an image dimension of 2 mm for a laser tube 1.8 cm in diameter.