Procedure of practical exercise with students on the pathogenic effect of accelerations on the organism

The effects of acceleration alone and coupled with administration of either aminazine (chlorpromazine- a sedative) or caffeine (a stimulant) on the development of kinetoses in mice were studied. The problem is presented as a method to teach students and to demonstrate the role of the nervous factor in the development of kinetosis

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

APPLICATION OF INNOVATIVE TECHNOLOGIES IN THE DEVELOPMENT OF FREIGHT AIRCRAFT FLEET

 According to Boeing World Air Cargo Forecast, international air freight will drive overall world air cargo growth through 2029, and world air cargo traffic will represent an average of 5.6 % for the following 20 years

Direct current driven by ac electric field in quantum wells

It is shown that the excitation of charge carriers by ac electric field with zero average driving leads to a direct electric current in quantum well structures. The current emerges for both linear and circular polarization of the ac electric field and depends on the field polarization and frequency. We present a micoscopic model and an analytical theory of such a nonlinear electron transport in quantum wells with structure inversion asymmetry. In such systems, dc current is induced by ac electric field which has both the in-plane and out-of-plane components. The ac field polarized in the interface plane gives rise to a direct current if the quantum well is subjected to an in-plane static magnetic field.Comment: 6 pages, 3 figure

Чотири листи М. П. Ковальського (Four letters of M. P. Kovalsky)

У статті наведено тексти листів видатного українського історика М. П. Ковальського до відомого українського історика о. Юрія Мицика, написаних у 1971–2006 рр., котрі є важливими джерелами до творчої біографії обох істориків, розвитку сучасної історичної науки. Подано також вступну статтю і коментар, котрі прояснюють обставини створення листів, згадувані в них події і персоналії

Direct detection of the relative strength of Rashba and Dresselhaus spin-orbit interaction: Utilizing the SU(2) symmetry

We propose a simple method to detect the relative strength of Rashba and Dresselhaus spin-obit interactions in quantum wells (QWs) without relying on the directional-dependent physical quantities. This method utilize the asymmetry of critical gate voltages that leading to the remarkable signals of SU(2) symmetry, which happens to reflect the intrinsic structure inversion asymmetry of the QW. We support our proposal by the numerical calculation of in-plane relaxation times based on the self-consistent eight-band Kane model. We find that the two different critical gate voltages leading to the maximum spin relaxation times [one effect of the SU(2) symmetry] can simply determine the ratio of the coefficients of Rashba and Dresselhaus terms. Our proposal can also be generalized to extract the relative strengths of the spin-orbit interactions in quantum wire and quantum dot structures.Comment: 5 pages, 4 figure

Spin-orbit Hanle effect in high-mobility quantum wells

We study the depolarization of optically oriented electrons in quantum wells subjected to an in-plane magnetic field and show that the Hanle curve drastically depends on the carrier mobility. In low-mobility structures, the Hanle curve is described by a Lorentzian with the width determined by the effective g-factor and the spin lifetime. In contrast, the magnetic field dependence of spin polarization in high-mobility quantum wells is nonmonotonic: The spin polarization rises with the magnetic field induction at small fields, reaches maximum and then decreases. We show that the position of the Hanle curve maximum can be used to directly measure the spin-orbit Rashba/Dresselhaus magnetic field.Comment: 4 pages, 3 figure

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