Glassy Dynamics Under Superhigh Pressure

Nearly all glass-forming liquids feature, along with the structural alpha-relaxation process, a faster secondary process (beta-relaxation), whose nature belongs to the great mysteries of glass physics. However, for some of these liquids, no well-pronounced secondary relaxation is observed. A prominent example is the archetypical glass-forming liquid glycerol. In the present work, by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we show that in glycerol a significant secondary relaxation peak appears in the dielectric loss at P > 3 GPa. We identify this beta-relaxation to be of Johari-Goldstein type and discuss its relation to the excess wing. We provide evidence for a smooth but significant increase of glass-transition temperature and fragility on increasing pressure.Comment: 5 pages, 5 figures, final version with minor changes according to referee demands and corrected Figs 1 and

Two liquid states of matter: A new dynamic line on a phase diagram

It is generally agreed that the supercritical region of a liquid consists of one single state (supercritical fluid). On the other hand, we show here that liquids in this region exist in two qualitatively different states: "rigid" and "non-rigid" liquid. Rigid to non-rigid transition corresponds to the condition {\tau} ~ {\tau}0, where {\tau}is liquid relaxation time and {\tau}0 is the minimal period of transverse quasi-harmonic waves. This condition defines a new dynamic line on the phase diagram, and corresponds to the loss of shear stiffness of a liquid at all available frequencies, and consequently to the qualitative change of many important liquid properties. We analyze the dynamic line theoretically as well as in real and model liquids, and show that the transition corresponds to the disappearance of high-frequency sound, qualitative changes of diffusion and viscous flow, increase of particle thermal speed to half of the speed of sound and reduction of the constant volume specific heat to 2kB per particle. In contrast to the Widom line that exists near the critical point only, the new dynamic line is universal: it separates two liquid states at arbitrarily high pressure and temperature, and exists in systems where liquid - gas transition and the critical point are absent overall.Comment: 21 pages, 8 figure

Electrotransport and magnetic properies of Cr-GaSb spintronic materials synthesized under high pressure

Electrotarnsport and magnetic properties of new phases in the system Cr-GaSb were studied. The samples were prepared by high-pressure (P=6-8 GPa) high-temperature treatment and identified by x-ray diffraction and scanning electron microscopy (SEM). One of the CrGa$_2$Sb$_2$ phases with an orthorhombic structure $Iba2$ has a combination of ferromagnetic and semiconductor properties and is potentially promising for spintronic applications. Another high-temperature phase is paramagnetic and identified as tetragonal $I4/mcm$

Observation of non-local dielectric relaxation in glycerol

Since its introduction, liquid viscosity and relaxation time $\tau$ have been considered to be an intrinsic property of the system that is essentially local in nature and therefore independent of system size. We perform dielectric relaxation experiments in glycerol, and find that this is the case at high temperature only. At low temperature, $\tau$ increases with system size and becomes non-local. We discuss the origin of this effect in a picture based on liquid elasticity length, the length over which local relaxation events in a liquid interact via induced elastic waves, and find good agreement between experiment and theory

Development of Instruction and Methodical Data Basis of the Institution as an Element of Biosafety Provision as Regards Works with Pathogenic Biological Agents

A set of documents concerning biological safety at the institutional level is prepared and put in to practice. Three levels of specialists` admission for works with pathogenic biological agents of the I-IV groups have been developed, substantiated and introduced. Considered are the variants of execution of coupled (simultaneous) work with PBA of different groups. The statement on control of disinfectants received by the institution defines the order of control execution as regards newly received disinfectants and correspondence of disinfectants` working solutions in the laboratories to the requirements of sanitary regulations. Demonstrated is practicability of the assessment of protective efficacy of air-cleaning filters in the exhaust ventilation systems of “contaminated” area rooms in the laboratories carrying out the works with PBA using bacterial aerosol and physical method

Application of Risk Assessment Methodology for Substantiation of Measures Complex on Provision of Safe Functioning of Mobile Laboratories of Specialized Anti-Epidemic Teams

A set of risk assessment methods was used for substantiation of safe functioning of mobile laboratories (ML) of specialized anti-epidemic teams (SAET). The utilized methods were borrowed from diverse spheres of activity and recommended for evaluation of biological hazard and risk associated with work with pathogenic biological agents. The obtained data represent the basis for biorisk management in SAET` ML functioning

Diode-pumped LiY<inf>0.3</inf>Lu<inf>0.7</inf>F<inf>4</inf>:Pr and LiYF<inf>4</inf>:Pr red lasers

© 2016 Astro Ltd.The laser quality LiY0.3Lu0.7F4:Pr and LiYF4:Pr fluoride single crystals were grown in Kazan University by the Bridgeman technique. Spectral-kinetic properties of LiY0.3Lu0.7F4:Pr and LiYF4:Pr crystals have been investigated. For the first time, laser oscillations of LiY0.3Lu0.7F4:Pr crystal have been obtained on 3P0 → 3F2 transitions (λ = 640 nm) under multimode diode pumping at 442 nm, with a slope efficiency of 9 %. Also, continuous-wave lasing has been obtained for LiYF4:Pr crystal at 640 nm under the same pumping condition with a slope efficiency of 8.5%. The maximum output power of 340 mW has been achieved for both crystals