RESUMEN
The time-dependent transport through a nanoscale device consisting of a single spin-degenerate orbital with on-site Coulomb interaction, coupled to two leads, is investigated. Various gate and bias voltage time dependences are considered. The key and new point lies in the proposed way to avoid the difficulties of the usual heavy computation when dealing with two-time Green's functions within the Keldysh formalism. The time-dependent retarded dot Green's functions are evaluated, in an efficient manner within a non-canonical Hubbard I approximation. Calculations of the time-dependent current are then presented in the wide-band limit for different parameter sets. A comparison between the method and the Hartree-Fock approximation is performed as well. It is shown that the latter cannot account reliably for dynamical aspects of transport phenomena.
Asunto(s)
Transporte de Electrón , Electrones , Nanocables/química , Puntos Cuánticos , Teoría Cuántica , Simulación por Computador , Modelos Químicos , Factores de TiempoRESUMEN
We present a control system, which allows an automatic optimization of the pulse train stability in a mode-locked laser cavity. In order to obtain real-time corrections, we chose a closed loop approach. The control variable is the cavity length, mechanically adjusted by gear system acting on the rear cavity mirror, and the controlled variable is the envelope modulation of the mode-locked pulse train. Such automatic control system maintains the amplitude of the mode-locking pulse train stable within a few percent rms during the working time of the laser. Full implementation of the system on an Nd:yttrium lithium fluoride actively mode-locked laser is presented.
Asunto(s)
Fluoruros , Rayos Láser , Litio , Neodimio , Itrio , Factores de TiempoRESUMEN
In this paper we present Hugoniot data for plastic foams obtained with laser-driven shocks. Relative equation-of-state data for foams were obtained using Al as a reference material. The diagnostics consisted in the detection of shock breakout from double layer Al/foam targets. The foams [poly(4-methyl-1-pentene) with density 130 > rho > 60 mg/cm3] were produced at the Institute of Laser Engineering of Osaka University. The experiment was performed using the Prague PALS iodine laser working at 0.44 microm wavelength and irradiances up to a few 10(14) W/cm2. Pressures as high as 3.6 Mbar (previously unreached for such low-density materials) where generated in the foams. Samples with four different values of initial density were used, in order to explore a wider region of the phase diagram. Shock acceleration when the shock crosses the Al/foam interface was also measured.
Asunto(s)
Actinomicosis/diagnóstico , Enfermedades Renales/diagnóstico , Absceso/diagnóstico , Absceso/patología , Absceso/cirugía , Actinomicosis/patología , Actinomicosis/cirugía , Adulto , Femenino , Humanos , Riñón/patología , Enfermedades Renales/patología , Enfermedades Renales/cirugía , Nefrectomía , Espacio RetroperitonealRESUMEN
Experimental studies in 60 rabbits with defects of the radius have shown that exposure to oxygenobarotherapy results in the greatest activization of osteoreparation in the early period after trauma with the formation of osseous matrix. The intensity of OBT sessions should be reduced along with the "maturation" of the osseous regenerate. The clinical application of OBT in 33 patients with defects of long tubular bones contributed to shortening the terms of rehabilitation of such patients.