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The stability of ferroelectric domain patterns at the nanoscale has been a topic of much interest for many years. We investigated the relaxation of the polarized state created by application of a local electric field using a conductive tip of a scanning probe microscope for the model uniaxial relaxor system Sr x Ba 1−x Nb 2 O 6 (SBN) in its pure and Ce-doped form. The temporal relaxation of the induced PFM contrast was measured at various temperatures. The average value of the induced contrast decreases during heating for all investigated crystals. Below the freezing temperature the induced state remains stable after an initial relaxation. Above the freezing temperature the induced state is unstable and gradually decays with time. The stability of the induced state is strongly affected by the measuring conditions, so continuous scanning results in a faster decay of the poled domain. The obtained effects are attributed to a decrease of the induced polarization and backswitching of the polarized area under the action of the depolarization field.

The paper presents systematized and synthesized data on the parameters and evolutionary sequence of metasomatic processes that accompanied interaction between Permian–Triassic trap complex and rocks of the sedimentary cover of the Siberian Platform at the large skarn iron deposits. Relations of the textural–compositional, morphological, and genetic diversity of the skarns and ores with the phases and stages of the origin of ore-bearing volcano-tectonic edifices are demonstrated with reference to the Korshunovskoe and Rudnogorskoe deposits. The genetic reconstructions are based on survey materials and data on the mineralogy of the rocks and ores (obtained by optical and scanning electron microscopy, microprobe analysis, EPR, Raman and IR spectroscopy, and by studying inclusions in minerals). A principally important feature of the volcano-tectonic edifices of the large mineral deposits is their multistage evolution and combinations of fluid-conducting zones, which are related to (1) volcanic apparatuses, (2) shallow-depth magmatic chambers (laccoliths) hosted in carbonate–salt rocks, and (3) multistage fracture structures produced by the collapse of the leached space. The major ore-bearing structures were formed simultaneously with the development of an intermediate magmatic chamber hosted in Cambrian carbonate–salt rocks beneath a seal of terrigenous sedimentary rocks. Magmatic-stage magnesian skarns with disseminated ores in them and in the calciphyres were produced during the prograde stage in the apical parts of the laccoliths, at contacts between the dolerites and dolomites. During the early prograde stage, skarn–ore bodies developed around injection bodies of globulated dolerites, laccoliths, and sills; stockworks and steep bodies of fragmentary magnesian and calcic skarns and ores were formed within the diatremes; and conformable bodies and veins were produced in the splay fracture zones. The later reactivation of faults and fractures and the involvement of connate brines and solutions from the evaporite complex triggered the redeposition of the ore masses, crystallization of the mineral assemblages of hydrated skarns, development of large domains of serpentine–chlorite–epidote–amphibole rocks, calcic skarns, and ores. Data on multiphase fluid inclusions in the forsterite, apatite, and halite indicate that the mineral-forming fluid initially was a highly concentrated solution–melt (total salinity of 60%) with high-density reduced gases. The magnesian skarns were formed during the following stages: (1) forsterite + fassaite + spinel + first-population magnetite (820–740°C); (2) phlogopite + titanite + pargasite + second-population magnetite (600–500°C), and (3) clinochlore + serpentine + tremolite + pyrrhotite + chalcopyrite (≥450°C).

The local switching by conductive tip of scanning probe microscope was studied in the non-polar cuts of Ce-doped Sr0.61Ba0.39Nb2O6 single crystals after creation of the single-domain state. The switched domains possessed the egg-shaped heads and wedge-like tails. The dependences of lengths of the domain head and tail and width of the domain head on the voltage and pulse duration were derived. The start voltage for growth of the domain tail was revealed. The fast relaxation of the domain head and slow relaxation of the domain tail were observed. The model of the forward domain growth by step generation and kink motion was used for explanation of the experimental results. The obtained knowledge can be used for the domain engineering in ferroelectrics.

We have studied the influence of initial domain structure on piezoelectric and dielectric properties of Sr0.61Ba0.39Nb2O6 single crystals slightly doped with Ce and Ni. Initial domain structure was created by zero-field cooling, in-field cooling, and partial switching. The difference in the frequency dependences of macroscopic piezoelectric response and temperature dependences of dielectric permittivity for various initial domain structures was revealed.

Ore mineral assemblages associated with various types of intrusive traps from the western sector of the Siberian Platform are reviewed. It was shown that various types of mineralization (Norilsk magmatic copper-nickel, Angaro-Ilim skarn-magnetite, and hydrothermal with Zn, Pb, Ag, and other metals) appear during the evolution of the fluid-magmatic systems. A suggestion about the high potential perspectives of this area for the revealing of large accumulation of various ore types was postulated.

The genesis of the soils having second humus horizon in the North-East of the European part of Russia was considered in the paper. The theory of the relict origin of the second humus horizon in sod-podzolic soils was confirmed on the basis of paleopalynological analysis. Data of paleopalinological study of sod-podzolic soils with complex organic profile are presented. In these soils, the remains of the relict humus horizon, which formed in the warmer Atlantic period of the Holocene under broad-leaved forests, have been preserved. It was revealed that despite the significant degree of destruction of the relict horizon, paleomorphs (pollen and plant spores) were preserved in it, which formed phytocenoses of broad-leaved forests. During the optimal period of the Holocene, the northern boundary of the spread of phytocenoses of coniferous-deciduous forests within the borders of the modern Kirov region of Russia presumably passed north of 58 degrees north latitude. Currently, in the region, broad-leaved forests in natural conditions have been preserved south of 56 degrees north latitude. The results will clarify the species composition of vegetation and the history of landscape development in the Kirov region of Russia in the Holocene.

—Using a mathematical statistics approach, we review the procedure for type classification of acoustic emission (AE) events into shear, tension, and collapse, proposed by Zang et al. (1998). The procedure is based on counting the signs of first pulses of waves arriving at acoustic sensors and is widely used in rock physics experiments. Under the assumption that the determination errors of first-pulse signs at sensors have uniform and independent distribution , the statistical significance and power of the type separation test are evaluated for a given number of sensors used. We consider and compare three methods of the construction of a statistical test based on the P -value approach and symmetric and asymmetric statistical hypothesis tests. Considering the results of the statistical study, we propose some practical recommendations for selecting a threshold to classify AE event types in experimental studies.

Long-term dynamics of the electric field of the midlatitude near-surface atmosphere in a wide range of temporal scales is analyzed according to multiyear observatory and seasonal field observations. It is found that the daily dynamics of the aeroelectric field at mid-latitudes most authentically repeats a diurnal variation for the winter months. It is stated that short-period pulsations of the electric field have a self-similar power-law spectrum. Spatio-temporal scales of the self-similarity interval are estimated and the nature of the generalized diffusive process of the aeroelectric pulsation generation is defined. Characteristics of the turbulent ΔE pulsations are analyzed. Estimates of interrelation between the dynamic (fractal dimensions, intermittency indices) and power (degrees of spectral index and structure function) ΔE characteristics are obtained. Mutual correlations between atmospheric electric field variations, vertical atmospheric electrical current density, space charge density, and atmospheric electrical conductivity are studied. It is shown that variations of the light atmospheric ion number density and space charge density are related with variations of the Radon-222 emanations. Spectral analysis of the space charge density variations is carried out. It is shown that the electrodynamic state of the surface atmosphere depends on the convective state of the atmospheric boundary layer.

An algorithm is developed for automated detection of the short-period Pc1 geomagnetic pulsations (frequency band f = 0.2–3 Hz) from the continuous time series of digital recording during 1998–2014 at the midlatitude Borok station. A digital catalog with the indication of time intervals of the presence and main morphological characteristics of Pc1 pulsations is created. Based on this catalog, the annual, seasonal, and diurnal dynamics of the midlatitude Pc1 pulsation activity is studied for 1998–2014. It is shown that the annual variation of the Pc1 occurrence has a maximum in 2005, i.e., at the end of the solar cycle decay phase, just as in the previous cycles. It is found that the minimum of the cases of Pc1 occurrence is observed in 2009, i.e., not at the maximum, just was the case in the previous cycles, but during the deep minimum of solar activity, which testifies to the untypical conditions in the magnetosphere during the unusually long minimum of the 23rd cycle. The seasonal variation of the Pc1 occurrence has a summer minimum when the series of Pc1 pulsations occur almost thrice as rarely as in winter. Besides, there are relatively small maxima at equinox. The diurnal behavior of Pc1 pulsations has the maxima in the morning and midnight sectors of the magnetosphere. By the superposed epoch analysis technique it is established that the maximal number of the cases of occurrence of Pc1 pulsations at the Borok observatory is observed on the fourth day after the global geomagnetic disturbances. The statistical distributions of pulsations amplitude and duration are obtained.

The results of in situ ground-based observations of radon volumetric activity carried out at the Borok Geophysical Observatory of Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences (58°04′ N; 38°14′ E) are presented. Modeling the characteristic diurnal variation in the ion production rate in the undisturbed midlatitude lower atmosphere above land is carried out. The Lagrangian stochastic model of turbulent transport is developed in application to determining the vertical profiles of radon activity for 222Rn and 220Rn isotopes and their radioactive decay products. The results calculated by the Lagrangian stochastic model are matched with the analytical solution for the free atmosphere. Based on the model, the estimate is obtained for the rate of radon outflow from the convective boundary layer to the free clear sky atmosphere. The implications of temperature stratification of the atmosphere for the vertical distribution of the ion production rate at the different radon emission rate are explored.