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991.
Myocardial infarction results from the rupture of an atherosclerotic plaque, which occurs in response to both mechanical stress
and inflammatory processes. In order experimentally observe flow into atherosclerotic coronary artery morphologies, a novel
technique for molding realistic compliant phantom featuring injection-molded inclusions and multiple layers has been developed.
This transparent phantom allows for particle image velocimetry (PIV) flow analysis and can supply experimental data to validate
computational fluid dynamics algorithms and hypothesis. 相似文献
992.
A new optical technique based on real time holographic interferometry in true colors has been implemented around the transonic
wind tunnel of the ONERA-Lille center to analyze 2D unsteady wake flows. Tests realized in color interferometry, real time
and double exposure, use simultaneously three wavelengths of a continuous waves laser (argon and krypton mixed) and holograms
are recorded on silver-halide single-layer panchromatic Slavich PFG03c plates. The very principle of real-time true color
holographic interferometry uses three primary wavelengths (red, green and blue) to record, under no-flow conditions, the interference
among the three measurement beams and the three reference beams simultaneously on a single reference hologram. After the holographic
plate is developed, it is placed on the test setup again in the position it occupied during exposure and the hologram is illuminated
again by the three reference beams and three measurement beams. A flat, uniform color can then be observed behind the hologram.
So a horizontal, vertical, or even circular fringe pattern can be formed and the achromatic central fringe can be made out
very clearly. The single color is used to determine the path difference zero on the interferograms. The flow studied was the
unsteady flow downstream of a cylinder placed crosswise in the test section. A sequence of hundred interferograms was recorded
on the flow around the cylinder at Mach 0.37. The vortex formation and dissipation phases can be seen very clearly, along
with the fringe beat to either side of the cylinder. 相似文献
993.
994.
995.
H. Akimune T. Yamagata S. Nakayama M. Fujiwara K. Fushimi K. Hara K. Y. Hara K. Ichihara K. Kawase K. Matsui K. Nakanishi A. Shiokawa M. Tanaka H. Utsunomiya M. Yosoi 《Physics of Atomic Nuclei》2004,67(9):1721-1725
Trinucleon molecular structures in 6He and 6Be were investigated by using the 6Li(7Li, 7Be)6He reaction at 455 MeV and 6Li(3He, t)6Be reaction at 450 MeV, respectively. Binary decays into t + t from a broad state at E x =18.0±1.0 MeV in 6He and into 3He + 3He from one at E x =18.0±1.2 MeV in 6Be, respectively, were observed by measuring trinucleon cluster decays in coincidence with reaction particles. The branching ratios for binary decay were estimated to be about 0.7 for 6He and 6Be. These large branching ratios show that a trinucleon cluster state exists as an isobaric partner around E x =18 MeV in 6He and 6Be. 相似文献
996.
V. F. Agekyan N. N. Vasil’ev A. Yu. Serov N. G. Filosofov G. Karczewski 《Physics of the Solid State》2004,46(9):1776-1780
Emission spectra of three Cd0.6Mn0.4Te/Cd0.5Mg0.5Te superlattices with Cd0.6Mn0.4Te quantum-well (QW) widths of 7, 13, and 26 monolayers, respectively, and the same thickness (46 monolayers) of the Cd0.5Mg0.5Te barriers have been studied. The QW width affects the shape and spectral position of the Mn2+ intracenter luminescence (IL) band as a result of the crystal field being dependent on the position of the manganese ion with respect to the interface. Measured in identical experimental conditions, the exciton luminescence as compared to the IL is substantially higher in intensity in a QW than in a bulk CdMnTe crystal. Some samples of superlattices and bulk crystals exhibit, in addition to the conventional IL band near 2.0 eV, a weaker band at about 1.45 eV. This band apparently derives from intracenter transitions in the Mn2+ ions in the regions where the crystal lattice has the rock-salt rather than the conventional zinc blende structure. 相似文献
997.
A. G. Milekhin A. I. Nikiforov M. Yu. Ladanov O. P. Pchelyakov S. Schulze D. R. T. Zahn 《Physics of the Solid State》2004,46(1):92-96
This paper reports on the results of resonant Raman scattering investigations of the fundamental vibrations in Ge/Si structures with strained and relaxed germanium quantum dots. Self-assembled strained Ge/Si quantum dots are grown by molecular-beam epitaxy on Si(001) substrates. An ultrathin SiO2 layer is grown prior to the deposition of a germanium layer with the aim of forming relaxed germanium quantum dots. The use of resonant Raman scattering (selective with respect to quantum dot size) made it possible to assign unambiguously the line observed in the vicinity of 300 cm?1 to optical phonons confined in relaxed germanium quantum dots. The influence of confinement effects and mechanical stresses on the vibrational spectra of the structures with germanium quantum dots is analyzed. 相似文献
998.
The incubation-period-based criterion for fracture is considered in terms of the Zhurkov kinetic model of fracture. Within the kinetic model, fracture is treated as a continuously developing process, which starts immediately after the application of a tensile load to a sample and consists in breaking of the interatomic bonds and gradual accumulation of broken bonds in the material in the course of a fracture test. For certain materials, the inclusion of the thermal-fluctuation mechanism for fracture in the incubation-period-based criterion significantly affects the position of the static branch of the time dependence of strength. Time dependences of strength are calculated for a number of materials. The experimental data are analyzed using the structural-time criterion for fracture, which allows one to obtain a unified time dependence of strength for quasi-static and high-rate short-term loadings. The temperature dependence of the incubation period (latent time) is calculated analytically, and a relation is found between the latent fracture time and the thermal vibration frequency of atoms. 相似文献
999.
S. A. Reshetnyak 《Physics of the Solid State》2004,46(6):1061-1067
The refractive index of surface spin waves propagating in a ferromagnetic medium with a nonuniform distribution of the parameters of uniaxial and orthorhombic magnetic anisotropies and exchange coupling is determined within the spin-density formalism. The coefficients of reflection and transmission of spin waves at the interface between two homogeneous magnets with different constants of uniaxial and orthorhombic magnetic anisotropies, exchange coupling, and saturation magnetization are calculated. The dependences of the intensity of a reflected wave and the refractive index on the wave frequency and the strength of an external dc homogeneous magnetic field are determined. 相似文献
1000.
A. V. Turik A. I. Chernobabov G. S. Radchenko S. A. Turik 《Physics of the Solid State》2004,46(12):2213-2216
Effective complex piezoelectric and dielectric constants of disordered heterogeneous systems, such as statistical mixtures consisting of spheroidal particles of the same orientation but with random distribution in space, are studied. It is found for the first time that, in such systems, there exists giant piezoelectric enhancement accompanied by giant relaxation of piezoelectric coefficients and permittivity. The piezoelectric and dielectric spectra differ considerably from the Debye spectra and have a Cole-Cole character. The dependence of the effects considered on the aspect ratios of the spheroids is investigated. The physical mechanisms responsible for the anomalous behavior of the piezoelectric coefficients and permittivity are considered. 相似文献