Mathematical model of an ionospheric communication channel with polarization-sensitive transmission coefficients

We describe a mathematical model for the ionospheric communication channel. The method of selective excitation of characteristic waves and the result of mathematical simulation of the channel operation on the basis of this model are shown.     

Sapphire needle capillaries for laser medicine

New devices for laser photochemical and thermal methods of treatment of tumors of the prostate, liver, thyroid gland, and brain are developed on the basis of sapphire needle capillaries. These needles allow one to increase the irradiation volume substantially, to obtain an optimal temperature distribution, to simplify the design, and to eliminate a system for cooling the device.     

Atom-sparing synthesis of tertiary diphosphine dichalcogenides from acetylenes and secondary phosphine chalcogenides

Secondary phosphine oxides and phosphine sulfides react with acetylene, methylacetylene, and phenylacetylene in the presence of strong bases (KOH-DMSO, KOH-THF) by the mechanism of double nucleophilic α,β-addition to form tertiary diphosphine dioxides and diphosphine disulfides in high yield (up to 97%).     

Continuous time vertex-reinforced jump processes

 We study the continuous time integer valued process , which jumps to each of its two nearest neighbors at the rate of one plus the total time the process has previously spent at that neighbor. We show that the proportion of the time before t which this process spends at integers j converges to positive random variables V _j , which sum to one, and whose joint distribution is explicitly described. We also show Received: 19 December 2000 / Revised version: 1 November 2001 / Published online: 17 May 2002     

Schrödinger equation for quasiparticles with variable effective mass

Feynman's method of quantization is extended to nonlinear systems with nonadditive Hamiltonian that is quadratic in the momenta. The Schrödinger equation for a quasiparticle whose effective mass depends on the coordinates and the time is derived as an example. The equations obtained can be used to study the dynamics of quasiparticles in inhomogeneous solid structures.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 126–129, September, 1977.     

Fragmentation,autoionization, and charge-decrease reactions of doubly and triply charged anthracene ions in the first field-free region of the mass spectrometer

Theoretical and Experimental Chemistry -