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81.
V. P. Germogenov O. M. Ivleva Ya. I. Otman L. E. Épiktetova 《Russian Physics Journal》1988,31(1):73-77
Studies have been carried out on the perfection of then-AlxGa1–xSb1–yAsy (0.12x0.26) layer grown on GaSb substrates under different conditions of lattice matching. During the relaxation of the mechanical stresses at first a system of tilt dislocations with a density of up to 5 · 105 cm–2 is formed while in thick layers (h 20 m) a network of misfit dislocations parallel to the heteroboundary is formed. The time required to dissolve a weighed amount of GaAs in the melt is shown to be of major importance for obtaining layers of a solid solution that are isoperiodic with the substrate. The entry of arsenic only in the initial portion of the epitaxial layer can reduce the dislocation density in the layer without decreasing the measured value of Aa. Dissolution of a weighed amount of GaAs in a Ga + Sb melt for two hours at T=730–750°C is sufficient to obtain layers of AlxGa1–xSb1–yAsy solid solution that are isoperiodic with the substrate.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 84–89, January, 1988.In conclusion, we thank L. V. Druzhinina for useful discussions as well as Z. V. Korotchenko, L. S. Khludkova, and F. S. Kim for assistance in the performance of the experiments. 相似文献
82.
Emőke-Ágnes Horvát Ferenc Járai-Szabó Yves Brechet Zoltán Néda 《Central European Journal of Physics》2012,10(4):926-935
Fracture patterns resulting from point-like impact acting perpendicularly on the plane of a commercial sodalime glass plate is modelled by a spring-block system. The characteristic patterns consist of crack lines that are spreading radially from the impact point and concentric arcs intersecting these radial lines. Experimental results suggest that the number of radial crack lines is scaling linearly with the energy dissipated during the crack formation process. The elaborated spring-block model reproduces with success the observed fracture patterns and scaling law. 相似文献
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86.
Diana B. Muñiz-Márquez Guillermo C. Martínez-Ávila Jorge E. Wong-Paz Ruth Belmares-Cerda Raúl Rodríguez-Herrera Cristóbal N. Aguilar 《Ultrasonics sonochemistry》2013,20(5):1149-1154
Bay leaves (BL) (Laurus nobilis L., Family: Laureceae) are traditionally used to treat some symptoms of gastrointestinal problems, such as epigastric bloating, impaired digestion, eructing and flatulence. These biological properties are mainly attributed to its phenolic compounds. In this paper, ultrasound-assisted extraction of phenolic compounds from Laurus nobilis L. (Laureceae) was studied.Effects of several experimental factors, such as sonication time, solid/liquid ratio and concentration of solvent on extraction of phenolic compounds were evaluated through a randomized complete block design with factorial treatment arrangement (33). The best extraction conditions were: 1 g plant sample with 12 mL of 35% ethanol, for 40 min, obtaining a yield of phenolic compounds of 17.32 ± 1.52 mg g?1 of plant. In addition, free radical-scavenging potential of DPPH and lipid oxidation inhibition, by linoleic acid peroxidation of the selected extract was measured in order to evidence their antioxidant properties. Results indicated that high amounts of phenolic compounds can be extracted from L. nobilis by ultrasound-assisted extraction technology. 相似文献
87.
A. A. Kamnev R. L. Dykman K. Kovács E. Kuzmann 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(6):722-725
Mössbauer spectroscopy is used for a comparative study of the rate of iron(III) reduction by 4-n-hexylresorcinol (4-n-HR, a chemical analog of microbial autoregulators excreted by cells into the environment that allow intercellular communication) in aqueous media in the pH range of 1.5–4.5 simulating acidic soil conditions. The concomitant process of 4-n-HR oxidation is monitored using UV spectrophotometry. 相似文献
88.
B. M. Abramov L. Álvarez-Ruso Yu. A. Borodin S. A. Bulychjov I. A. Dukhovskoy A. I. Khanov A. P. Krutenkova V. V. Kulikov M. A. Matsuk I. A. Radkevich A. I. Sutormin E. N. Turdakina M. J. Vicente Vacas 《Physics of Atomic Nuclei》2002,65(2):229-235
The spectra of fast π + mesons from the π ? A → π + X reaction on A=6Li, 7Li, and 16O nuclei at a primary momentum of p 0=0.72 GeV/c (T 0=0.59 GeV) are measured at emission-angle values in the range ?=0°–14°. The results obtained in this way are compared with experimental data taken in other studies at lower energies and with the results of model calculations. The energy dependence of the cross sections and of shadowing effects is analyzed for the reactions in question that occur on lithium isotopes. 相似文献
89.
Angular dispersion of femtosecond pulses in a Gaussian beam 总被引:2,自引:0,他引:2
The angular dispersion of spatially Gaussian laser pulses, unlike for plane waves, changes with the distance between the disperser and the observer and between the beam waist and the disperser. The formula that is derived is experimentally verified by use of a high-precision measurement technique. Because the angular dispersion of a Gaussian beam is substantially different from that of a plane wave after the same disperser, the phenomenon may be of special interest for short-pulsed laser systems, for which alignment of the stretcher-compressor system for zero residual angular dispersion is essential. 相似文献
90.
GERHARD NÄGELE ADOLFO J. BANCHIO MARKUS KOLLMANN RAPHAËL PESCHÉ 《Molecular physics》2013,111(18):2921-2933
The static and dynamic properties of 2- and 3-dimensional dispersions of strongly interacting colloidal spheres are examined. Quasi-2-dimensional dispersions of particles interacting by long range electrostatic and dipolar magnetic forces, respectively, are investigated using Brownian dynamics computer simulations with hydrodynamic interactions included. The dynamics of 3-dimensional bulk dispersions of charge-stabilized and neutral colloidal spheres is determined from a fully self-consistent mode-coupling scheme. For systems with long range repulsive interactions the dynamic correlation functions are shown to obey dynamic scaling in terms of a characteristic relaxation time related to the mean particle distance. Hydrodynamic interactions introduce a second characteristic length scale, and they lead to more restricted scaling behaviour with an enhancement of self-diffusion and, for 2-dimensional systems, to the divergence of the short-time collective diffusion coefficient. As a consequence of dynamic scaling, a dynamic criterion for the onset of colloidal freezing related to long-time self-diffusion is shown to be equivalent to a static freezing criterion related to the 2- and 3-dimensional static structure factors. Alternative freezing criteria are given in terms of the long-time and the mean collective diffusion coefficients. 相似文献