Predicting the deformation characteristics of polymer materials

Theoretical methods of predicting the deformation characteristics of polymers are considered. The principles of reduced variables are examined. The relation between characteristics functions of polymers is analyzed. A prediction method is considered for polymers; the method is based upon the use of macroscopical mechanical models having a basis in terms of physics.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 147–152, March–April, 1973.     

Critical Dynamics of the Phase Transition to the Superfluid State

Theoretical and Mathematical Physics - In papers devoted to superfluidity, the generally accepted statement that the dynamics of the corresponding phase transition is described by the stochastic...     

Anomalous heating of a system of dust particles in a gas-discharge plasma

The coexistence of regions of negatively charged macroparticles with substantially different kinetic temperatures in a highly nonideal dusty plasma in a dc glow discharge has been observed experimentally. An explanation of the observed anomalous heating of the system of dust particles in a gas-discharge plasma is proposed on the basis of a molecular-dynamics model. Pis’ma Zh. éksp. Teor. Fiz. 66, No. 6, 392–397 (25 September 1997)     

Stationary wave beams in strongly nonlinear three-dimensional inhomogeneous media

We derive an asymptotic expression for the evolution of stationary beams in strongly nonlinear three-dimensional media. Formulas are obtained for the distribution of the beam amplitude and phase velocity, and effectively solvable equations are constructed for the beam axial line. It is shown that with power-function nonlinearity, the determination of the beam axial line is separated from the determination of the field concentrated near this line.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 148, pp. 52–60, 1985.     

Experimental scheme of quantum cryptography on the nonorthogonal states with time shift and a minimum number of optical components

A new scheme of experimental quantum cryptography on the nonorthogonal states is described. Nonorthogonality is achieved by the time shift of states in different messages. For this scheme to be efficient, it is sufficient to balance the arms of an interferometer at the receiver and transmitter ends to an accuracy of 1–2 cm. This is a fundamental advantage of this scheme over, e.g., the most developed cryptosystem based on phase coding, where the maximum transmission distance has been achieved. In the latter system, the arms of the interferometer need to be balanced with an accuracy of fractions of a micron for a distance of several tens of kilometers.     

Equations for the vibrations of a plate with general anisotropy

The exact form of the displacement field for an elastic layer with general anisotropy and nonuniform thickness is constructed. The low-frequency part of the solution, which satisfies the equations for the vibrations of a plate, is found.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 165, pp. 122–135, 1987.     

Simple delay scheme for quantum cryptography based on a Mach-Zehnder optic fiber interferometer

A simple experimental scheme is proposed for a relativistic quantum cryptosystem based on a Mach-Zehnder optic fiber interferometer. In this scheme, quantum mechanical laws, along with the restrictions imposed by the Special Relativity, ensure the detection of any eavesdropping attempt.     

Quantum cryptography based on the energy-time uncertainty relation

A new quantum cryptosystem based on the energy-time uncertainty relation is proposed. This cryptosystem can be implemented with both biphotonic states and single photons. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 11, 882–887 (10 June 1996)     

Nonstationary normal waves in a thin,curved waveguide of variable cross section

The propagation of nonstationary normal waves in a thin waveguide with variable properties along its course is considered. Along space-time rays the eikonal and transport equations are integrated, and asymptotic formulas for these waves are obtained. It is observed that for some types of initial data the effect of overturning of a wave packet of a normal wave is possible.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 89, pp. 210–218, 1979.