NMR line width with allowance for the distribution of correlation times

Mathematical expressions have been derived for NMR line width on the basis of the general theory of magnetic resonance absorption described by Kubo-Tomita. Allowance is made for the distribution of correlation times of molecular motion in polymers described by the curves of Fuoss-Kirkwood, Cole-Cole, Cole-Davidson and Gavrilyaka-Negami. © 1974

Free nuclear induction in amorphous polymers and viscous liquids above the glass temperature

An experimental and theoretical study has been made of the temperature dependence of the form of the free induction signal (FIS) using PS and a low molecular viscous liquid, dioctylphthalate, as examples. A relationship for the form of the FIS is obtained on the basis of a hypothesis about the existence, in any viscous system, of random magnetic fields which, over a wide temperature range, are not averaged to zero by movement. © 1978

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

Comparison of seismic signatures of flares obtained by SOHO/MDI and GONG instruments

The first observations of seismic responses to solar flares were carried out using time-distance (TD) and holography techniques applied to SOHO/MDI Dopplergrams obtained from space and un-affected by terrestrial atmospheric disturbances. However, the ground-based network GONG is potentially a very valuable source of sunquake observations, especially in cases where space observations are unavailable. In this paper we present updated technique for pre-processing of GONG observations for application of subjacent vantage holography. Using this method and TD diagrams we investigate several sunquakes observed in association with M and X-class solar flares and compare the outcomes with those reported earlier using MDI data. In both GONG and MDI datasets, for the first time, we also detect the TD ridge associated with the September 9, 2001 flare. Our results show reassuringly positive identification of sunquakes from GONG data that can provide further information about the physics of seismic processes associated with solar flares.Comment: 19 pages, 6 figures, accepted to Astrophysical Journa

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

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

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

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