The results of introduction of East Asian origin flowering plants in the southwest of Central Russian upland

The article is devoted to the study of the results of introduction of East Asian origin flowering plants, growing in the dendrological collection of Belgorod Botanical Garden. The most important ecological and biological characteristics of the plants were studied. The estimation of the growth and development nature of introduced species, according to their resistance to the complex of unfavorable factors, was carried ou

Coexistence or Separation of the Superconducting, Antiferromagnetic, and Paramagnetic Phases in Quasi One-Dimensional (TMTSF)2PF6 ?

We report on experimental studies of the character of phase transitions in the quasi-1D organic compound (TMTSF)2PF6 in the close vicinity of the borders between the paramagnetic metal PM, antiferromagnetic insulator AF, and superconducting SC states. In order to drive the system through the phase border P_0(T_0), the sample was maintained at fixed temperature T and pressure P, whereas the critical pressure P_0 was tuned by applying the magnetic field B. In this approach, the magnetic field was used (i) for tuning (P-P_0), and (ii) for identifying the phase composition (due to qualitatively different magnetoresistance behavior in different phases). Experimentally, we measured R(B) and its temperature dependence R(B,T) in the pressure range (0 - 1)GPa. Our studies focus on the features of the magnetoresistance at the phase transition between the PM and AF phases, in the close vicinity to the superconducting transition at T~1K. We found pronounced history effects arising when the AF/PM phase border is crossed by sweeping the magnetic field: the resistance depends on a trajectory which the system arrives at a given point of the P-B-T phase space. In the transition from the PM to AF phase, the features of the PM phase extends well into the AF phase. At the opposite transition from the AF to PM phase, the features of the AF phase are observed in the PM phase. These results evidence for a macroscopically inhomogeneous state, which contains macroscopic inclusions of the minority phase. When the system is driven away from the transition, the homogeneous state is restored; upon a return motion to the phase boundary, no signatures of the minority phase are observed up to the very phase boundary.Comment: 10 figures, 23 page

Photoemission of Bi2_2Se3_3 with Circularly Polarized Light: Probe of Spin Polarization or Means for Spin Manipulation?

Topological insulators are characterized by Dirac cone surface states with electron spins aligned in the surface plane and perpendicular to their momenta. Recent theoretical and experimental work implied that this specific spin texture should enable control of photoelectron spins by circularly polarized light. However, these reports questioned the so far accepted interpretation of spin-resolved photoelectron spectroscopy. We solve this puzzle and show that vacuum ultraviolet photons (50-70 eV) with linear or circular polarization probe indeed the initial state spin texture of Bi$_2$Se$_3$ while circularly polarized 6 eV low energy photons flip the electron spins out of plane and reverse their spin polarization. Our photoemission calculations, considering the interplay between the varying probing depth, dipole selection rules and spin-dependent scattering effects involving initial and final states explain these findings, and reveal proper conditions for light-induced spin manipulation. This paves the way for future applications of topological insulators in opto-spintronic devices.Comment: Submitted for publication (2013

Forming information competency of future teachers in the frame of professional pedagogical activities

In article results of the scientific research devoted to studying of a problem of training of future teachers in the conditions of education informatization are stated. Using a method of the analysis of theoretical sources, the author focuses attention to relevance of informatization of education, vocational training of future teachers of chemistry, formation of their information competence of professional activity

Non-invasive diagnostics of extrahepatic portal hypertension at the proliferative processes in the pancreas

The study of hemodynamics in 199 patients with chronic pancreatitis and pancreatic cancer was performed with use of radiological diagnostics methods: ultrasound research, CT and. portal scintigraphy. Ultrasound examination with color and. power Doppler, CT with 3D-reconstruction give an idea of the local hemodynamic changes in extrahepatic portal hypertension and. can identify preoperative anatomic and. topographic relationship of great vessels in their involvement in mass lesion of the pancreas. Portal scintigraphy with accuracy 83 %, sensitivity 62 % and. specificity 100 % functional condition evaluates collateral flow in extrahepatic portal hypertensio