Spin relaxation and combined resonance in two-dimensional electron systems with spin-orbit disorder

Disorder in spin-orbit (SO) coupling is an important feature of real low-dimensional electron structures. We study spin relaxation due to such a disorder as well as resulting abilities of spin manipulation. The spin relaxation reveals quantum effects when the spatial scale of the randomness is smaller than the electron wavelength. Due to the disorder in SO coupling, a time-dependent external electric field generates a spatially random spin-dependent perturbation. The resulting electric dipole spin resonance in a two-dimensional electron gas leads to spin injection in a frequency range of the order of the Fermi energy. These effects can be important for possible applications in spintronics.Comment: 4 pages, 3 figure

Ultrastructure of meristem and root cap of pea seedlings under spaceflight conditions

Data of electron microscopic analysis of meristem and root cap of pea seedlings grown aboard the Salyut-6 orbital research station in the Oazis apparatus and in the laboratory are presented. The main morphological and anatomical characteristics of the test and control plants are shown to be similar. At the same time, some differences are found in the structural and functional organization of the experimental cells as compared to the controls. They concern first of all the plastic apparatus, mitochondria and Golgi apparatus. It is assumed that cell function for certain periods of weightlessness on the whole ensures execution of the cytodifferentiation programs genetically determined on the Earth. Biochemical and physiological processes vary rather markedly due to lack of initially rigorous determination

Spin dephasing and pumping in graphene due to random spin-orbit interaction

We consider spin effects related to the random spin-orbit interaction in graphene. Such a random interaction can result from the presence of ripples and/or other inhomogeneities at the graphene surface. We show that the random spin-orbit interaction generally reduces the spin dephasing (relaxation) time, even if the interaction vanishes on average. Moreover, the random spin-orbit coupling also allows for spin manipulation with an external electric field. Due to the spin-flip interband as well as intraband optical transitions, the spin density can be effectively generated by periodic electric field in a relatively broad range of frequencies.Comment: 9 pages, 7 figure

Surface hardening of stainless steel by runaway electronspreionized diffuse discharge in air atmosphere

In this paper we present microhardness measurements of stainless steel surface treated by diffuse discharge in air atmosphere. The cleaning from carbon in comparison to the initial sample was observed at a depth exceeding 20 nm. The oxygen concentration was also increased in comparison to that in the initial sample at a depth of up to about 50 nm. Comparative analysis shows that after treatment the microhardness of stainless steel surface increased in 2 times due to interaction of near-surface layers with product of plasma chemical reactions produced in diffuse discharge

Robust to impurity-scattering spin Hall effect in two-dimensional electron gas

We propose a mechanism of spin Hall effect in two-dimensional electron gas with spatially random Rashba spin-orbit interaction. The calculations based on the Kubo formalism and kinetic equation show that in contrast to the constant spin-orbit coupling, spin Hall conductivity in the random spin-orbit field is not totally suppressed by the potential impurity scattering. Even if the regular contribution is removed by the vertex corrections, the terms we consider, remain. Therefore, the intrinsic spin-Hall effect exists being, however, non-universal.Comment: 4+ pages, 2 figure

Cyclotron Resonance Assisted Photocurrents in Surface States of a 3D Topological Insulator Based on a Strained High Mobility HgTe Film

We report on the observation of cyclotron resonance induced photocurrents, excited by continuous wave terahertz radiation, in a 3D topological insulator (TI) based on an 80 nm strained HgTe film. The analysis of the photocurrent formation is supported by complimentary measurements of magneto-transport and radiation transmission. We demonstrate that the photocurrent is generated in the topologically protected surface states. Studying the resonance response in a gated sample we examined the behavior of the photocurrent, which enables us to extract the mobility and the cyclotron mass as a function of the Fermi energy. For high gate voltages we also detected cyclotron resonance (CR) of bulk carriers, with a mass about two times larger than that obtained for the surface states. The origin of the CR assisted photocurrent is discussed in terms of asymmetric scattering of TI surface carriers in the momentum space. Furthermore, we show that studying the photocurrent in gated samples provides a sensitive method to probe the effective masses and the mobility of 2D Dirac surface states, when the Fermi level lies in the bulk energy gap or even in the conduction band

Комбіноване лікування хворої з ендометріоїдною пухлиною передньої черевної стінки

Комбіноване лікування хворої з ендометріоїдною пухлиною передньої черевної стінк

The changes of kortizol/insulin balance in pregnant women with obesity

The changes of kortizol / insulin balance were probed in pregnant women with obesity. The level of insulin grows and correlation a kortizol / insulin is diminished in pregnant women with different degree of obesity. It is indication of metabolic misbalance and progress of insulin resistention (stability to insulin) pregnenetrioldione. ; Цель работы – исследовать изменение баланса кортизол/инсулин у беременных женщин с ожирением. Рост гиперинсулинемии на фоне снижения соотношения кортизол/инсулин в направлении контроль→ожирение отображает дисбаланс регуляции метаболизма и прогрессирования инсулинорезистентности у беременных женщин с ожирением разной степени

Endothelial dysfunction of the fetoplacental complex in women with obesity

Гістохімічним методом з використанням непрямої імунопероксидазної реакції з моноклональними антитілами досліджена активність ендотеліальної та індуцибельної ізоформ синтази оксида азоту (еNOS та іNOS) в стінці судин тканин плаценти жінок з фізіологічною масою тіла та з ожирінням ІІ ступеня. В групі вагітних з ожирінням про розвиток ендотеліальної дисфункції плацент свідчить зменшення активності еNOS, збільшення активності іNOS, а також зростання в 5,8 раз співвідношення іNOS / еNOS порівняно з показником у вагітних з фізіологічною масою тіла. Activities of endothelial and inducible isoforms of nitric oxide synthase (еNOS and іNOS) in blood vessel walls of placental tissues in women with class II obesity and women with physiologic body mass were studied histochemically using an indirect immunoperoxidase reaction with monoclonal antibodies. We found a decrease of eNOS activity, an increase of iNOS activity and an increase of іNOS / еNOS ratio in pregnant women with obesity compared to pregnant women with physiologic body mass