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71.
Yu. D. Chashechkin V. E. Prokhorov 《Journal of Experimental and Theoretical Physics》2016,122(4):748-758
Consistent optical and acoustic techniques have been used to study the structure of hydrodynamic disturbances and acoustic signals generated as a free falling drop penetrates water. The relationship between the structures of hydrodynamic and acoustic perturbations arising as a result of a falling drop contacting with the water surface and subsequent immersion into water is traced. The primary acoustic signal is characterized, in addition to stably reproduced features (steep leading edge followed by long decay with local pressure maxima), by irregular high-frequency packets, which are studied for the first time. Reproducible experimental data are used to recognize constant and variable components of the primary acoustic signal. 相似文献
72.
In this paper, problems related to the approximation of a holomorphic function f on a compact subset E of the complex plane C by rational functions from the class of all rational functions of order (n,m) are considered. Let ρ
n,m
= ρ
n,m
(f;E) be the distance of f in the uniform metric on E from the class . We obtain results characterizing the rate of convergence to zero of the sequence of the best rational approximation { ρ
n,m(n)
}
n=0
∞
, m(n)/n
→
θ
∈ (0,1] as n
→
∞ . In particular, we give an upper estimate for the liminf
n →∞
ρ
n,m(n)
1/(n+m(n))
in terms of the solution to a certain minimum energy problem with respect to the logarithmic potential. The proofs of the
results obtained are based on the methods of the theory of Hankel operators.
June 16, 1997. Date revised: December 1, 1997. Date accepted: December 1, 1997. Communicated by Ronald A. DeVore. 相似文献
73.
Korobov A. I. Shirgina N. V. Kokshaiskii A. I. Prokhorov V. M. 《Acoustical Physics》2019,65(2):151-157
Acoustical Physics - Results of experimental investigation into the effect of reversible mechanical loading–unloading on linear and nonlinear properties of n?AMg6/C60 nanostructured... 相似文献
74.
Physics of the Solid State - Objective factors that allow the experiment on growing crystals of a Ge–Si–Sb solid solution on the Soyuz–Apollo spacecraft to take a special place... 相似文献
75.
Shigefumi Mori Yuri Prokhorov 《Proceedings of the Steklov Institute of Mathematics》2009,264(1):131-145
We prove that a terminal three-dimensional del Pezzo fibration has no fibers of multiplicity >6. We also obtain a rough classification
of possible configurations of singular points on multiple fibers and give some examples.
To the memory of Professor Vasily Alekseevich Iskovskikh 相似文献
76.
V.Yu. Ivanov A.A. Mukhin V.D. Travkin A.S. Prokhorov A.M. Kadomtseva Yu.F. Popov G.P. Vorob’ev K.I. Kamilov A.M. Balbashov 《Journal of magnetism and magnetic materials》2006
Multiferroic ground states with a spatially modulated antiferromagnetic structure and electric polarization have been revealed in Eu1−xYxMnO3 (0.2?x?0.5) single crystals. While the slightly substituted (x?0.1) compounds exhibited a transition from the incommensurate (IC) to the canted antiferromagnetic (CAF) state at TCA<TN, the transitions from IC to commensurate ferroelectric (C/FE) phase were observed at Tlock<TN for x>0.2. Various phase transitions were observed in the magnetic fields up to 250 kOe along a, b, c axes by magnetization, magnetostriction and electric polarization measurements which show an existence of a spontaneous electric polarization below Tlock. 相似文献
77.
High-resolution shadow visualization and high-frequency sonar detection are applied to separate out the density wake and a fine streaky structure in the vicinity of a vertical plate in motion in salt-stratified water. The length of the sounding acoustic wave is taken to be approximately equal to the universal microscale $\delta _N^v = \sqrt {{v \mathord{\left/ {\vphantom {v N}} \right. \kern-0em} N}}$ , where ν and N are the kinematic viscosity and the buoyance frequency. In the spectra of the vertical oscillations of the acoustic contrast some characteristic frequencies ω are separated out and used to calculate the local Stokes microscales $\delta _\omega ^v = \sqrt {{v \mathord{\left/ {\vphantom {v \omega }} \right. \kern-0em} \omega }}$ in the density wake region. The scales determined from the data of independent optical and acoustic measurements are in agreement with each other. 相似文献
78.
A. S. Mikheykin A. S. Anokhin V. I. Torgashev E. S. Zhukova B. P. Gorshunov A. S. Prokhorov A. A. Bush 《Bulletin of the Russian Academy of Sciences: Physics》2018,82(3):266-268
The structure of an M-type lead hexaferrite (magnetoplumbite) crystal is studied via the diffraction of synchrotron radiation. The crystal model contains two iron ions positions with dynamic disorder. The dynamics of the crystal lattice in the temperature range of 80 to 775 K is studied by Raman scattering. Particular attention is given to the discussing the nature of the local disorder of iron ions in the trigonal bipyramidal environment of oxygen ions. 相似文献
79.
A. I. Korobov N. V. Shirgina A. I. Kokshaiskii V. M. Prokhorov 《Acoustical Physics》2018,64(4):415-421
The paper presents results from experimental studies on the influence of loading–unloading processes on the mechanical, linear, and nonlinear properties of the strain-hardening polycrystalline aluminum alloy AMg6 (Rus). The stress–strain curve is measured for AMg6 samples under high-cycle loading–unloading up to fracture of a sample. The microhardness of the sample is measured before and after its fracture. It has been found that the loading–unloading process leads to strain hardening of the AMg6 alloy. The influence of strain hardening of AMg6 on its linear and nonlinear elastic properties is studied by an ultrasonic method. To study the nonlinear elastic properties for different domains of the loading curve, we used the Thurston–Brugger method and spectral method by studying the efficiency of second acoustic harmonic generation. The experimental results are discussed. 相似文献
80.
L.G. Prokhorov D.V. Koptsov M.S. Matiushechkina V.P. Mitrofanov K. Haughian J. Hough S. Rowan A.A. van Veggel P.G. Murray G.D. Hammond K. Tokmakov 《Physics letters. A》2018,382(33):2186-2191
Silicon optics suspended by silicon ribbons or silicon fibers and kept at low temperature are being considered, because of promising optical and mechanical properties, for the test masses of third generation interferometric gravitational-wave detectors. To interconnect the suspension elements the technique of hydroxide catalysis (or silicate) bonding can be used. In order to estimate the bond loss a tuning fork was fabricated from silicon ribbons, which were then silicate bonded. The temperature dependence of mechanical loss of this tuning fork was measured in the temperature range of 95–295 K. The ratio of the energy stored in the bond layer to the total energy of the tuning fork was calculated by numerical simulation. This provided an upper limit of the bond loss as a function of the temperature. It is at 123 K, a proposed operating temperature of cryogenically operating ground based interferometric gravitational-wave detectors. 相似文献