Intense Internal Waves and Their Manifestation in the Interference Patterns of Received Signals on Oceanic Shelf. Part II

Physics of Wave Phenomena - Data of the SWARM-95 experiment, where intense internal waves on a stationary path led to coupling of acoustic source field modes, have been processed. The...     

Bottom Reverberation in the Presence of Intense Internal Waves

Acoustical Physics - The problem of modeling the broadband coherent field of low-frequency bottom reverberation under conditions of hydrodynamic variability associated with the motion of intense...     

Acoustic Diagnosis of Internal Waves on the Black Sea Shelf According to Tomographic Experiment Data

Acoustical Physics - On the northeastern shelf of the Black Sea in 2010, a tomographic experiment was carried out on the counterpropagation of phase-shift keyed acoustic signals. During the day,...     

Numerical Simulation of Hydro- and Seismoacoustic Waves on the Shelf

Acoustical Physics - A finite element method is used for three-dimensional numerical simulation of hydro- and seismoacoustic waves in shallow water, generated by harmonically oscillating sources....     

Space-Frequency Interference Structure of Acoustic Fields in Oceanic Waveguides

Laws manifesting themselves in the formation of the space-frequency distribution of the intensity of the acoustic field generated by a point source of wide-band radiation are considered. Most attention is concentrated on the study of the effect of diffraction focusing on the formation of the interference structure of the acoustic field.     

Reflections of Nonstationary Signals in Media with Intense Fluctuations of Irregularities

With the help of the invariant embedding method, we obtain an equation for the kernel of the backscattering operator and find numerically its solutions corresponding to the response of the medium to an incident delta-impulse. The statistical characteristics of reflections of such impulses are determined in the case of intense fluctuations of irregularities given the logarithmic derivative of the medium impedance is a continuous stationary centered Gaussian process with the unit variance and a finite correlation radius. We study the temporal evolution of the statistical distribution of reflected signals. Examples of reflections for various shapes of incident impulses are discussed.     

On Mechanism of Influence of Low Intense Millimeter Waves on Air Content in Water

The two-stage mechanism is offered, on which the millimeter waves rises concentration of free air in water. At first, millimeter waves localize heating in a volume of the sample, creating supersaturated concentration of the dissolved air in a fluid. Then superfluous air diffuses in embryonic microbubbles present in a fluid. The experimental data confirm the mechanism suggested.     

Nonlinear Damping and Nonlinear Phase Shift of Intense Spin Waves in Screened Ferrite Films

Technical Physics - We analyze for the first time nonlinear damping and nonlinear phase shift of intense surface spin waves in screened yttrium–iron garnet films. Nonlinear damping...     

Interference of Spin Waves in Arrays of Microwaveguides Based on Yttrium-Iron Garnet Films

Technical Physics - Effects of propagation and interference of spin waves in an eight-port magnonic structure in the form of a 2 × 2 array of microwaveguides based on yttrium-iron garnet films...     

两相干平面波照射球体的远场干涉及直径测量

提出一种球远场干涉理论模型,即两相干平面波以任意夹角照射表面光滑球体,其反射波在远场发生干涉.推出两反射波在远场的光程差公式,并用远场干涉准确测量球直径,给出了测量球直径的公式.用分光仪、CCD照相机、氦氖激光器、光学平台和电脑等组成测量系统,给出使用原始激光束测量球直径的方法.将远场干涉法测量结果与阿贝比较仪测量结果进行比较,相对差为0.2%;使用高斯光束所产生的测量误差为5×10-5 mm且可略.此测量方法还可对相机镜头畸变实现自校正.结果表明理论和测量方法正确,用高斯激光束测量球直径可行.     

机械波的衍射和干涉现象的MATLAB数值模拟

运用MATLAB模拟了机械波的衍射和干涉现象,通过形象直观的图形演示能够加深学生对波的衍射和干涉现象的理解,激发学生的学习兴趣,提高教学质量。     

The Interference of Magnetoelastic Waves in an Yttrium Iron Garnet Film

Physics of the Solid State - The interference of excited and received by current antennae magnetoelastic waves counterpropagating in an yttrium iron garnet film is experimentally studied. It is...     

Analysis of the Influence of Long-Wavelength Surface Waves on the Formation of the Wind-Wave-Scattered Acoustic Field in Oceanic Waveguides

Acoustical Physics - The paper considers the interference structure during underwater pulsed sounding in the ocean associated with acoustic field diffraction by wind waves. When calculating the...     

Tomographic Maps of Typical Radio Signals and Their Superpositions

Following the procedure of noncommutative tomography of analytic signals, some typical radio signals are analyzed. Tomograms of rectangular pulses, delta-pulses, and Gaussian signals are presented. Properties of the noncommutative tomography method are discussed.     

Characterization of Labyrinthine Patterns and Their Evolution

An invariant measure δ is introduced to quantify the disorder in extended locally striped patterns. It is invariant under Euclidean motions of the pattern, and vanishes for a uniform array of stripes. Irregularities such as point defects and domain walls make nonzero contributions to the measure. The evolution of random initial states to labyrinthine patterns is analyzed through the time evolution of δ. This behavior is configuration independent, and exhibits two phases each with a logarithmic decay in δ.