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51.
Ostrovsky LA 《The Journal of the Acoustical Society of America》2004,116(6):3348-3353
Nonlinear interaction of counterpropagating waves in solids is considered by using a general approach taking into account only the cumulative (resonant) nonlinear perturbations giving a nonzero contribution over the period and, consecutively, potentially able to significantly modify the linear solution. Different stress-strain relations are addressed, including those with hysteresis which serve as basic models for the recent acoustic experiments with rock and metals. An important case of the interaction of counterpropagating waves with close amplitudes in a high-Q resonator (bar) with hysteresis is specially addressed and compared with the case of a ring resonator. 相似文献
52.
The HeH2 van der Waals complex has been identified in a molecular beam produced by a cryogenic (T0=24.7 K) free jet expansion of a 1% H2 mixture in 99% 4He gas. The weakly bound HeH2 complexes in the beam are identified via their first order diffraction angles after passing through a 100 nm period transmission grating. An electron impact mass spectrometer analysis of the diffraction patterns is used to discriminate against ion fragments of the constituent gas clusters. 相似文献
53.
Ultrasound-modulated light tomography is a new technique that combines laser light and ultrasound to provide a representation of the light density inside turbid media. We present a method that can produce two- or three-dimensional light density representations with standard ultrasonic pulses. This technique should allow simple, direct fusion of ultrasonic images with optical tomography. 相似文献
54.
Chevillard L Roux SG Levêque E Mordant N Pinton JF Arneodo A 《Physical review letters》2003,91(21):214502
We use the multifractal formalism to describe the effects of dissipation on Lagrangian velocity statistics in turbulent flows. We analyze high Reynolds number experiments and direct numerical simulation data. We show that this approach reproduces the shape evolution of velocity increment probability density functions from Gaussian to stretched exponentials as the time lag decreases from integral to dissipative time scales. A quantitative understanding of the departure from scaling exhibited by the magnitude cumulants, early in the inertial range, is obtained with a free parameter function D(h) which plays the role of the singularity spectrum in the asymptotic limit of infinite Reynolds number. We observe that numerical and experimental data are accurately described by a unique quadratic D(h) spectrum which is found to extend from h(min) approximately 0.18 to h(max) approximately 1. 相似文献
55.
We describe the experimental observation of a crystal structure formed by glycerol droplets suspended in a nematic liquid crystal. The structure exhibits a high density hexagonal ordering. We have experimentally observed a noticeable interaction between droplets with tangential boundary conditions. Within the scope of known models we discuss the nature of appropriate mechanisms of the interaction. 相似文献
56.
Multidimensional analogues of Bohr's theorem on power series 总被引:2,自引:0,他引:2
Lev Aizenberg 《Proceedings of the American Mathematical Society》2000,128(4):1147-1155
Generalizing the classical result of Bohr, we show that if an -variable power series converges in -circular bounded complete domain and its sum has modulus less than 1, then the sum of the maximum of the modulii of the terms is less than 1 in the homothetic domain , where . This constant is near to the best one for the domain
57.
A combination of light and focused ultrasound waves provides a unique way to obtain directly three-dimensional absorption data in a turbid medium. We present the combination of an ultrasound wave and light in which both the input and the output optodes are on the same side of the sample (reflectance geometry). This technique permits local detection in depth of the presence of a purely absorbing object, without further mathematical processing. It is a promising technique for medical imaging and monitoring of tissues. 相似文献
58.
We have synthesized bulk RuSr2RECu2O8 (RE=Eu, Gd and Ho) compounds using the ammonium nitrate melt technique. The phase purity of the samples decreases as the ionic radii of the RE element decreases. For RE=Ho, magnetic Sr2HoRuO6 and CuO were formed instead of the 1212 phase. The magnetization vs. temperature curves of the samples are similar to those of the samples prepared using the solid-state reaction method. The magnetic anomalies observed in M-T curves are discussed. 相似文献
59.
60.
Olga N. Kazheva Andrey V. Kravchenko Irina A. Lobanova Vladimir I. Bregadze Lev I. Buravov 《Journal of organometallic chemistry》2009,694(15):2336-450
New molecular conductors on the base of 8,8′-diiodo cobalt bis(dicarbollide) anion (TTF)[8,8′-I2-3,3′-Co(1,2-C2B9H10)2] (1), (BMDT-TTF)4[8,8′-I2-3,3′-Co(1,2-C2B9H10)2] (2) and (BEDT-TTF)2[8,8′-I2-3,3′-Co(1,2-C2B9H10)2] (3) were synthesized and their crystal structures and electrical conductivities were determined. All the radical cation salts prepared were found to be semiconductors. Some regularities in the crystal structures of the TTF-based radical cation salts with bis(dicarbollide) complexes of transition metals are discussed. 相似文献