Condensation of the atomic relaxation vibrations in lead-magnesium-niobate at T=T∗T=T^*

We present neutron diffraction, dielectric permittivity and photoconductivity measurements, evidencing that lead-magnesium niobate experiences a diffuse phase transformation between the spherical glass and quadrupole glass phases, in the temperature interval between 400 K and 500 K, with the quadrupole phase possessing extremely high magnitudes of dielectric permittivity. Our analysis shows that the integral diffuse scattering intensity may serve as an order parameter for this transformation. Our experimental dielectric permittivity data support this choice. These data are important for the aplications desiring giant dielectric responses, in a wide temperature intervals and not related to electron's excitations.Comment: 6 figure

SPANISH-SPEAKING COMMUNITY: SEARCHING FOR STANDARD SPANISH

The article deals with the current issue of standard language, looking into the situation in the Spanish-speaking community where the language they share is to ensure comfortable interaction in everyday communication. A common language norm has been seen as vital for the Spanish language area if it is to preserve its linguistic and cultural identity in the globalized world. The study analyzes the history of emerging Standard Spanish concept and its recognition by the linguistic community. The author addresses the interpretations of the Spanish pluricentric norm based on the standardized literary language that, in its turn, shapes the so-called Pan-Hispanic language norm. The Spanish language norms are explored not only from the traditional academic prescriptive point of view, but in the current Pan-Hispanic context as well

Cestovne cementno betonske modificirane strukture

This paper describes the experimental investigations of various mixtures for preparation of road coatings. Modern additives are as additives used - Sika Mix Plus and Sika Visco Crete 20NE. The results of research show the cost influence of cement and additives on the strength of cement-concrete especially depending on the time of solidification. The properties of concrete mixtures and cement concrete in the final result are characterized by durability developed compositions pavements.U ovom radu opisana su eksperimentalna ispitivanja raznih smjesa za izradu cestovnih premaza. Kao aditivi korišteni su moderni aditivi; Sika Mix Plus i Sika Visco Crete 20НЕ. Prikazani su rezultati istraživanja utjecaja troškova cementa i aditiva na čvrstoću cement-betona ovisno i o vremenu skrućivanja. Svojstva betonskih mješavina i cement-betona u konačnici su karakterizirana trajnošću razvijene smjese (pripravka)

New data on acritarchs from the Upper Ordovician of the Tungus basin, Siberian platform

© 2014, Estonian Academy Publishers. All rights reserved. Distinctive late Ordovician acritarch assemblages have been discovered for the first time from about a 100 m sedimentary succession exposed along the Bol′shaya Nirunda River in Siberia. The studied stratigraphic interval includes the uppermost Baksian, Dolborian, Nirundian and Burian regional stages, which correspond to the Katian-?lowermost Hirnantian global stages. Acritarch assemblages from the Dolbor Regional Stage are exceptionally diverse and include aside from the longranging taxa several unique (endemic) morphotypes and a number of distinctive stratigraphically valuable species, well known outside Siberia. The occurrence of the acritarchs widespread outside Siberia is potentially important for interregional biostratigraphic correlations and might also play a significant role in biogeographic reconstructions. Having in mind that the Siberian palaeocontinent was located in a low-latitude tropical area during the entire Ordovician, the presence of taxa typical of cold-water settings along the Peri-Gondwana margin can be regarded as an additional evidence for penetration of cool-water currents into the epicontinental Tungus basin in the Upper Ordovician

Cluster superconductivity in the magnetoelectric Pb(Fe1/2Sb1/2)O3 ceramics

We report the observation of cluster (local) superconductivity in the magnetoelectric Pb(Fe1/2Sb1/2)O3 ceramics prepared at a hydrostatic pressure of 6 GPa and temperatures 1200-1800 K to stabilize the perovskite phase. The superconductivity is manifested by an abrupt drop of the magnetic susceptibility at the critical temperature TC 7 K. Both the magnitude of this drop and TC decrease with magnetic field increase. Similarly, the low-field paramagnetic absorption measured by EPR spectrometer drops significantly below TC as well. The observed effects and their critical magnetic field dependence are interpreted as manifestation of the superconductivity and Meissner effect in metallic Pb nanoclusters existing in the ceramics. Their volume fraction and average size were estimated as 0.1-0.2% and 140-150 nm, respectively. The superconductivity related effects disappear after oxidizing annealing of the ceramics.Comment: 9 pages, 5 figure