The soil conditions of the oak stand in the south-west part of Belarus

In the soil and climatic conditions of the oak stands (Quercus robur L.) grown installed: features of the state land-ground-water conditions on the water phy sical properties and moisture capacity; the regu-larities of distribution and content of nutrients were revealed; the granulometric composition of soil were established and the group and factional composition of humus were determined. The studies found that in the Bi alowieza Forest oak-woods grow on sod-podzolic and brown forest sandy and sabulous soils underlain by moraine loam. Oak-woods in the floodplains of Pripyat grow on floodplain sod gley sabulous soils with content of physical clay in humus horizons up to 20%. Soil conditions of oaks by water-physical characteristics, moisture reserves and agrochemical indicators are better in floodplain forests, while by density and granulometric texture – in upland types of oak-woods

Features of collection of spicy-aromatic plants in the botanical garden

The article presents the results of studying the coll ection material of spice and aromatic plants in the Botanical Garden of Belarusian State Agricultural Academy based on morphological, morphometrical and phenological characteristics. It also presents data on yield in a phase of technological maturity, seed productivity as well as specifies basic quality indicators. Collection of spicy-aromatic plants in the Botani cal Garden of BSAA is represented by 58 species that belong to 14 tribes and 40 genera. Collection of spicy-aromatic pl ants is divided into three sections: the most common, rarely used and advanced culture. Research new varieties of spicy-aromatic plants ( Ocimum basilicum L. (Volodar, Nastena, Magiya), Ocimum tenuiflorum L. (Istochnik), Allium × proliferum (Allium cepa × Allium fistulosum) (Uzgorak), Allium odorum L. (Vodar), Borago officinalis L. (Blakit), Geranium macrorrhizum L. (Tanyusha)) that are included in the State Re gister of varieties of the Republic of Belarus. Varieties has a complex of economically valuable sings and are used as a vegetable and decor plants

Anharmonicity due to Electron-Phonon Coupling in Magnetite

We present the results of inelastic x-ray scattering for magnetite and analyze the energies and spectral widths of the phonon modes with different symmetries in a broad range of temperature 125<T<293 K. The phonon modes with X_4 and Delta_5 symmetries broaden in a nonlinear way with decreasing temperature when the Verwey transition is approached. It is found that the maxima of phonon widths occur away from high-symmetry points which indicates the incommensurate character of critical fluctuations. Strong phonon anharmonicity induced by electron-phonon coupling is discovered within ab initio calculations which take into account local Coulomb interactions at Fe ions. It (i) explains observed anomalous phonon broadening, and (ii) demonstrates that the Verwey transition is a cooperative phenomenon which involves a wide spectrum of phonons coupled to charge fluctuations condensing in the low-symmetry phase.Comment: 5 pages, 5 figures, accepted in Physical Review Letter

Inelastic X-ray scattering studies of phonon dispersions in superconductors at high pressures

Electron-phonon interaction is of central importance for the electrical and heat transport properties of metals, and is directly responsible for charge-density-waves or (conventional) superconducting instabilities. The direct observation of phonon dispersion anomalies across electronic phase transitions can provide insightful information regarding the mechanisms underlying their formation. Here, we review the current status of phonon dispersion studies in superconductors under hydrostatic and uniaxial pressure. Advances in the instrumentation of high resolution inelastic X-ray scattering beamlines and pressure generating devices allow these measurements to be performed routinely at synchrotron beamlines worldwide.Comment: 8 pages, 6 figures. Invited review submitted to Superconductor Science and Technology, Focus issue on Hydride & High-Pressure Superconductors. References in figure caption fixed. Hyperlinks adde

Short-Range Correlations in Magnetite above the Verwey Temperature

Magnetite, Fe$_3$O$_4$, is the first magnetic material discovered and utilized by mankind in Ancient Greece, yet it still attracts attention due to its puzzling properties. This is largely due to the quest for a full and coherent understanding of the Verwey transition that occurs at $T_V=124$ K and is associated with a drop of electric conductivity and a complex structural phase transition. A recent detailed analysis of the structure, based on single crystal diffraction, suggests that the electron localization pattern contains linear three-Fe-site units, the so-called trimerons. Here we show that whatever the electron localization pattern is, it partially survives up to room temperature as short-range correlations in the high-temperature cubic phase, easily discernible by diffuse scattering. Additionally, {\it ab initio} electronic structure calculations reveal that characteristic features in these diffuse scattering patterns can be correlated with the Fermi surface topology.Comment: 7 pages, 6 figure

Phonon surface mapping of graphite: disentangling quasi--degenerate phonon dispersions

The two-dimensional mapping of the phonon dispersions around the $K$ point of graphite by inelastic x-ray scattering is provided. The present work resolves the longstanding issue related to the correct assignment of transverse and longitudinal phonon branches at $K$. We observe an almost degeneracy of the three TO, LA and LO derived phonon branches and a strong phonon trigonal warping. Correlation effects renormalize the Kohn anomaly of the TO mode, which exhibits a trigonal warping effect opposite to that of the electronic band structure. We determined the electron--phonon coupling constant to be 166$\rm(eV/\AA)^2$ in excellent agreement to $GW$ calculations. These results are fundamental for understanding angle-resolved photoemission, double--resonance Raman and transport measurements of graphene based systems

Changing energy accelerated turbulent fluid flow in the pipeline according to spectral analysis

За результатами теоретичних і експериментальних досліджень пришвидшеної течії рідини в циліндричному напірному трубопроводі проведено якісну оцінку спектрального складу енергії турбулентного потоку. Отримані густини спектрів нарізних відстанях від стінки труби. Згідно оцінок, передача енергії між низькими і високими частотами в нестаціонарному потоці суттєво відрізняються від передачі енергії в стаціонарному потоці.According to the results of theoretical and experimental studies of accelerated fluid flow in a cylindrical pressure pipe made a qualitative assessment of the spectral composition of the energy of turbulent flow. Density spectra obtained at different distances from the pipe wall. According to estimates, the transfer of energy between the low and high frequencies in unsteady flow significantly different from the energy transfer in a steady stream. In the transition to the low-frequency components of turbulent currents of the spectra in the near-wall local rate of flow with a relatively large part of the total energy than in the core flow. In steady flow relative share of low-energy component decreases with the increase of average flow velocity (number Re). Transient currents reverse process occurs after the turbulence of flow turbulence is a small-scale and large-scale development of the current portion of the increase.По результатам теоретических и экспериментальных исследований ускоренного течения жидкости в цилиндрическом напорном трубопроводе проведена качественная оценка спектрального состава энергии турбулентного потока. Полученные плотности спектров на разных расстояниях от стенки трубы. По оценкам, передача энергии между низкими и высокими частотами в нестационарном потоке существенно отличаются от передачи энергии в стационарном потоке