ABOUT DYNAMICS OF THE GEOPOLITICAL POSITION OF THE NORTH-EAST OF RUSSIA IN THE 17-TH-21-ST CENTURIES

Purpose: In the article, the changes in the geopolitical situation on the North-East for four preceding, partial centuries are considered. Methodology: Up to the inclusion in the structure of Russia, this extensive region (2.3 million km2) with the considerable natural-resources potential has actually existed out of the world geopolitical processes, basically, because of the extremeness of the natural climatic conditions, remoteness from the centers of world civilization and limited technical and technological capabilities in those times. Result: The different stages in the state of the geopolitical position of the region in prior centuries are identified and their repeatedly and multidirectional varying characteristics during the period in question are reported. It is also emphasized that the measures attempted by Russia for strengthening of the geopolitical position on the North-East gave rise abroad to the negative response consonant with the current ones practically at all considered stages. The current stage is considered as a period of the drastically varying external geopolitical conditions and increased technical capabilities when the geopolitical significance of the North-East for Russia increases by a factor of many times. Applications: This research can be used for universities, teachers, and students. Novelty/Originality: In this research, the model of About Dynamics of the Geopolitical Position of the North-East of Russia in the 17-th-21-st Centuries is presented in a comprehensive and complete manner

Negative high-frequency differential conductivity in semiconductor superlattices

We examine the high-frequency differential conductivity response properties of semiconductor superlattices having various miniband dispersion laws. Our analysis shows that the anharmonicity of Bloch oscillations (beyond tight-binding approximation) leads to the occurrence of negative high-frequency differential conductivity at frequency multiples of the Bloch frequency. This effect can arise even in regions of positive static differential conductivity. The influence of strong electron scattering by optic phonons is analyzed. We propose an optimal superlattice miniband dispersion law to achieve high-frequency field amplification

Stable Spin Precession at one Half of Equilibrium Magnetization in Superfluid 3He-B

New stable modes of spin precession have been observed in superfluid 3He-B. These dynamical order parameter states include precession with a magnetization S=pS_{eq} which is different from the equilibrium value S_{eq}. We have identified modes with p=1, 1/2 and \approx 0. The p=1/2 mode is the second member of phase correlated states of a spin superfluid. The new states can be excited in the temperature range 1-T/T_c \lesssim 0.02 where the energy barriers between the different local minima of the spin-orbit energy are small. They are stable in CW NMR due to low dissipation close to T_c.Comment: submitted to Physical Review Letters, 4 pages, revtex, 4 Figures in ftp://boojum.hut.fi/pub/publications/lowtemp/LTL-96005.p