Anomalous splitting in microwave mode-beating spectra of semiconductor ring lasers

Mode-beating spectra are investigated in long-perimeter (1.028 cm) monolithically integrated multiple-quantum-well semiconductor ring lasers. The beating line near 8 GHz is found to be split into two components. With increasing pumping current, a normal component shifts to lower frequencies, while an anomalous higher-frequency component shifts in the opposite direction. It is suggested the anomalous blue-shifting line results from power-induced perturbation of the refractive index in the vicinity of a strong mode.     

Conservation of water resources problems of small rivers in Russia

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 8, pp. 1–5, August, 1994.     

Molecular dynamics-based refinement of nanodiamond size measurements obtained with dynamic light scattering

The determination of particle size by dynamic light scattering uses the Stokes–Einstein relation, which can break down for nanoscale objects. Here, we employ a molecular dynamics simulation of fully solvated 1–5 nm carbon nanoparticles for the refinement of the experimental data obtained for nanodiamonds in water by using dynamic light scattering. We performed molecular dynamics simulations in differently sized boxes and calculated nanoparticles diffusion coefficients using the velocity autocorrelation function and mean-square displacement. We found that the predictions of the Stokes–Einstein relation are accurate for nanoparticles larger than 3 nm while for smaller nanoparticles the diffusion coefficient should be corrected and different boundary conditions should be taken into account.     

Estimation of fault-tolerance of the parallel control computing systems: A new approach

A new approach to estimating the fault-tolerance of the parallel control computing systems relies on the mathematical model-based determination of the probability of successful completion in a given schedule time of an arbitrary set of interdependent jobs (tasks) with random times of job execution and asynchronous job redundancy. The estimates were determined both for the standard execution of a set of tasks and for the case of single malfunction (fault or failure) of any computing system processor detected at execution of any job from the set. The basic distinction of this approach lies in that here the numerical values of the reliability parameters (probabilities or intensities of faults or failures) of the computing resources are neither given nor used.     

Characteristics of the numerical solution of the heat-conduction equation at early times

A criterion is presented for choosing time steps t and space steps x in an implicit scheme for obtaining a numerical solution of the unsteady heat-conduction equation at early times.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 33, No. 3, pp. 519–521, September, 1977.     

The structure of nanocomposite 1D cationic conductor crystal@SWNT

Nanocomposites consisting of one-dimensional (1D) crystals of the cationic conductors CuI, CuBr and AgBr inside single-walled carbon nanotubes, mainly (n, 0), were obtained using the capillary technique. 1D crystal structure models were proposed based on the high resolution transmission electron microscopy performed on a FEI Titan 80-300 at 80 kV with aberration correction. According to the models and image simulations there are two modifications of 1D crystal: hexagonal close-packed bromine (iodine) anion sublattice (growth direction <001>) and 1D crystal cubic structure (growth direction <112>) compressed transversely to the nanotube (D(m) ～1.33 nm) axis. Tentatively this kind of 1D crystal can be considered as monoclinic. One modification of the anion sublattice reversibly transforms into the other inside the nanotube, probably initiated by electron beam heating. As demonstrated by micrographs, copper or silver cations can occupy octahedral positions or are statistically distributed across two tetrahedral positions. A 1DAgBr@SWNT (18, 0; 19, 0) pseudoperiodic 'lattice distortion' is revealed resulting from convolution of the nanotube wall function image with 1D cubic crystal function image.     

Stability of xanthates in sulfite media

Journal of Mining Science -