307 research outputs found
Scientific, institutional and personal rivalries among Soviet geographers in the late Stalin era
Scientific, institutional and personal rivalries between three key centres of geographical research and scholarship (the Academy of Sciences Institute of Geography and the Faculties of Geography at Moscow and Leningrad State Universities) are surveyed for the period from 1945 to the early 1950s. It is argued that the debates and rivalries between members of the three institutions appear to have been motivated by a variety of scientific, ideological, institutional and personal factors, but that genuine scientific disagreements were at least as important as political and ideological factors in influencing the course of the debates and in determining their final outcome
Dynamics of pH-sensitive nitroxide radicals in water adsorbed in ordered mesoporous molecular sieves by EPR Spectroscopy
A spin pH probe technique was used to study the influence of the channel diameter on the EPR spectra of pH-sensitive nitroxide radicals (NR) located in the channels of the mesoporous molecular sieves MCM-41 and SBA-15 with diameters ranging from 2.3 to 8.1 nm. From EPR spectra analysis and the results of the NR retention by the mesoporous molecular sieves upon washing with an aqueous KCl solution, the regularities of NR molecular location inside the channels were studied. The obtained dependence of the fraction of the radical molecules in the fast motional regime (with the rotational correlation times, τc = 2 × 10-11 s-9 × 10-11s) in the channels of the mesoporous molecular sieves as a function of pH indicates that both NR in the fast and slow motional regime (with τc = 8 × 10 -9s-7 × 10-10s) may be used for estimation of the solution acidity inside the channels and of the near-surface electrical potential. © 2013 Elsevier Inc. All rights reserved
Inhomogeneous ground state and the coexistence of two length scales near phase transitions in real solids
Real crystals almost unavoidably contain a finite density of dislocations. We
show that this generic type of long--range correlated disorder leads to a
breakdown of the conventional scenario of critical behavior and standard
renormalization group techniques based on the existence of a simple,
homogeneous ground state. This breakdown is due to the appearance of an
inhomogeneous ground state that changes the character of the phase transition
to that of a percolative phenomenon. This scenario leads to a natural
explanation for the appearance of two length scales in recent high resolution
small-angle scattering experiments near magnetic and structural phase
transitions.Comment: 4 pages, RevTex, no figures; also available from
http://www.tp3.ruhr-uni-bochum.de/archive/tpiii_archive.htm
Solid 4He and the Supersolid Phase: from Theoretical Speculation to the Discovery of a New State of Matter? A Review of the Past and Present Status of Research
The possibility of a supersolid state of matter, i.e., a crystalline solid
exhibiting superfluid properties, first appeared in theoretical studies about
forty years ago. After a long period of little interest due to the lack of
experimental evidence, it has attracted strong experimental and theoretical
attention in the last few years since Kim and Chan (Penn State, USA) reported
evidence for nonclassical rotational inertia effects, a typical signature of
superfluidity, in samples of solid 4He. Since this "first observation", other
experimental groups have observed such effects in the response to the rotation
of samples of crystalline helium, and it has become clear that the response of
the solid is extremely sensitive to growth conditions, annealing processes, and
3He impurities. A peak in the specific heat in the same range of temperatures
has been reported as well as anomalies in the elastic behaviour of solid 4He
with a strong resemblance to the phenomena revealed by torsional oscillator
experiments. Very recently, the observation of unusual mass transport in hcp
solid 4He has also been reported, suggesting superflow. From the theoretical
point of view, powerful simulation methods have been used to study solid 4He,
but the interpretation of the data is still rather difficult; dealing with the
question of supersolidity means that one has to face not only the problem of
the coexistence of quantum coherence phenomena and crystalline order, exploring
the realm of spontaneous symmetry breaking and quantum field theory, but also
the problem of the role of disorder, i.e., how defects, such as vacancies,
impurities, dislocations, and grain boundaries, participate in the phase
transition mechanism.Comment: Published on J. Phys. Soc. Jpn., Vol.77, No.11, p.11101
Modern Conception of the Control over the Abundance of Carriers and Vectors of Plague in the Territory of the Russian Federation
Disinfestation and deratization remain the main ways of non-specific disease prophylaxis in natural plague foci. Modern strategies, tactics, methods and means of control over carriers and vectors of plague and associated infectious diseases are selected with due consideration to epidemiological potential of territories, epizootic activity of a foci, peculiarities of population ecology of animals that are of a medical significance, preservation of biodiversity in natural ecosystems, and the requirements for human and natural environments protection from pollutants
Observation of a new excitation in bcc solid 4He by inelastic neutron scattering
We report neutron scattering measurements of the phonons in bcc solid 4He. In
general, only 3 accoustic phonon branches should exist in a monoatomic cubic
crystal. In addition to these phonon branches, we found a new ''optic-like''
mode along the [110] direction. One possible interpretation of this new mode is
in terms of localized excitations unique to a quantum solid.Comment: Text and 4 figures, to appear in Phys. Rev. Let
Amplified spontaneous emission induced peculiarities of the passively Q-switched diode pumped erbium laser dynamics
Foreign Investment in Russia: Problems and Solutions
Russia, like any country embarking on the path of radical market reform, must define its strategy regarding foreign capital. Practically all developing and rapidly developing countries, especially in the last forty years, have actively encouraged foreign investment in their economies in the form of direct private investment and loans. Naturally, it is not easy to accept the experience of outsiders. Every country resolves this problem in its own way. Foreign investment is a critical question for the "postcommunist" states of Eastern Europe and the former USSR which are in the process of forming market relations and are searching for a way out of the grave economic crisis confronting them. It is not just a question of the lack of internal savings for the speedy modernization of their economies.
- …