Precession and motional slowing of spin evolution in a high mobility two-dimensional electron gas

Optical spin-dynamic measurements in a high-mobility n-doped GaAs/AlGaAs quantum well show oscillatory evolution at 1.8 K consistent with a quasi-collision-free D'yakonov-Perel'-Kachorovskii regime. Above 5 K evolution becomes exponential as expected for collision-dominated spin dynamics. Momentum scattering times extracted from Hall mobility and Monte Carlo simulation of spin polarization agree at 1.8 K but diverge at higher temperatures, indicating the importance of electron-electron scattering and an intrinsic upper limit for the spin-relaxation rate.     

Effect of neutron irradiation on the lifetime of polycaprolactam

On the basis of a study of the temperature-time dependence of polycaprolactam irradiated with thermal neutrons, it has been shown that strength and lifetime and the parameters which determine lifetime vary as functions of the radiation dose.     

Estimate of the pressure distribution for the nonlinear verigin problem in the two-dimensional radial case

A study is made of the problem of two-dimensional radial displacement by gas of liquid from an unbounded uniform stratum. A comparison theorem is used to obtain lower and upper bounds for the pressure distribution. Calculations made using the obtained expressions showed that the difference between the upper and lower bounds is a fraction of a percent. Thus, in a calculation of the pressure a high degree of accuracy is achieved by using the lower bound for it.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 153–155, May–June, 1983.     

Berberis alkaloids. XXVI. An investigation of the alkaloids ofBerberis amurensis

In addition to alkaloids isolated previously, young shoots of Berberis amurensis Rupr. have yielded berberrubine, oxyacanthine, and pseudopalmatine, and the new amorphous base amurenine. It's structure has been established on the basis of spectral characteristics and chemical transformations.     

Calculation of the concentration fields of solid and fluid phases in the flow of a chemically active fluid through a porous medium

The flow of a chemically active fluid through a porous medium is considered. Under certain assumptions, an analytical solution is obtained which describes the distribution of the concentration of the chemically active component and the variation of the solidphase porosity. On the basis of the results obtained, the optimization of the hydrochloric acid treatment of wells is considered.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 78–81, March–April, 1985.