Binaural unmasking of the periodic component in the envelope of an amplitude-modulated signal

A binaural unmasking of a tone component that is present in an amplitude-time noise envelope of a high-frequency signal is studied. The signal has the form of a sinusoidal carrier of frequency 2000–5000 Hz amplitude modulated by a low-frequency signal. The modulating function is a mixture of a 300-Hz tone (interaurally inphase or antiphase) and a dichotic masking noise within 0–400 Hz, this mixture being subjected to a half-wave linear rectification. The listener has to detect the rhythmic component in the modulating noise function. It is shown that, under the aforementioned conditions, the binaural difference in masking levels grows up to 25 dB with increasing carrier frequency but drastically decreases in the case of a masking of the low-frequency part of the basilar membrane in the vicinity of 300 Hz. The lateralization based on the interaural phase of a 100% amplitude modulation by a 300-Hz tone at a carrier frequency within 2000 to 5000 Hz also drastically decreases (in our experiments) when the low-frequency part of the basilar membrane is masked.     

Effective equation of nonlinear pulse evolution in a randomly anisotropic medium

Propagation of a light pulse through a weakly inhomogeneous optical fiber is analyzed. The non-linear envelope equation describing the evolution of polarized pulses is determined by statistical properties of inhomogeneities in the optical fiber. The isotropic Manakov system of equations is shown to be applicable in the presence of high-frequency small-scale defects in the fiber. In the presence of only large-scale inhomogeneities, the signal dynamics are described by an anisotropic system of equations.     

Nonlinear cyclotron-impurity resonance in semiconductors

The nonlinear absorption of electromagnetic radiation by electrons in a quantizing magnetic field is investigated. The inclusion of multiphoton processes is shown to result in additional peaks in the absorption curve. The shape and arrangement of these peaks were found. The absorption is shown to depend on the electric field strength in the electromagnetic wave nonlinearly and nonmonotonically. The results obtained are in good agreement with experimental data.     

Electroacoustic oscillations of aluminum oxide particles in the thermal plasma

The frequencies of natural electroacoustic oscillations of aluminum oxide particles in a laminar disperse aluminum flame are determined experimentally using the capacitive method. A computational model is proposed for estimating the natural frequency of oscillations of charged particles in the smoky plasma taking into account the Doppler effect. It is shown that, for a natural frequency of oscillations of 51 kHz, two measured maxima at frequencies of 30 and 60 kHz in the oscillation spectrum correspond to the Doppler frequencies.     

Isotopic effect in the width of a giant dipole resonance in light nuclei

An isotopic effect in the widths of giant dipole resonances is established on the basis of an analysis of the latest systematics of photoabsorption cross sections for nuclei containing 12 to 65 nucleons. This effect arises owing to isospin splitting of a giant resonance and is enhanced by its configuration splitting.     

Dielectric properties of liquid crystals of the cyano derivative compounds with different fragments in the molecular core

This paper reports on the results of investigations into the influence of variations in the chemical composition of the aromatic core of cyano-containing molecules of liquid crystals on their dielectric properties in the frequency range 1–2000 MHz. It is shown that the dispersion of the longitudinal permittivity is adequately described by the sum of two Debye processes with different weighting factors and relaxation times. The frequency dependence of the transverse permittivity is well approximated by the Debye process with a continuous distribution of relaxation times in a specified range. It is established that the replacement of one benzene ring in the biphenyl core of the 5CB liquid-crystal molecule by a cyclohexane (or bicyclooctane) fragment leads to a considerable decrease in both relaxation times for the longitudinal permittivity, a change in the low-frequency limit of the relaxation time range for the transverse permittivity, and the evolution of the frequency dependence of the dielectric anisotropy.     

Elasticity and inelasticity of biomorphic silicon carbide ceramics

The effect of the vibration strain amplitude on the Young modulus and ultrasonic absorption (internal friction) in biomorphic SiC ceramics is investigated in the temperature range 116–296 K. The biomorphic SiC ceramics is prepared through pyrolysis of eucalyptus with subsequent infiltration of silicon. It is demonstrated that the vibration loading of samples in air and under vacuum is accompanied by a number of unexpected effects. The behavior of the studied ceramics is governed by at least two mechanisms, which, to a large extent, are responsible for the elastic and inelastic properties of the material. One mechanism is associated with the adsorption-desorption of environmental molecules (hypothetically, owing to the presence of pores and residual carbon), and the other mechanism involves microplastic deformation due to the motion of dislocations or other (similar) structural units.     

Hysteretic galvano-mechanical effect on charging and discharging ionistor structures

The size of an ionistor capacitor structure is found to change during its charging and discharging. The specific feature of this effect that distinguishes it from other known effects of changing sizes under electric and magnetic fields (the piezoelectric effect and striction) is the complete hysteresis; i.e., the size reached under the exposure remains unchanged after the field is turned off.     

Formation of an icosahedral structure during crystallization of nickel nanoclusters

The crystallization of nickel nanoclusters is investigated using a molecular dynamics simulation with tight-binding potentials. The formation of a cluster structure depends on the cooling conditions. Slow cooling results in the formation of a face-centered cubic structure, whereas fast cooling, according to the data obtained in 40% of the simulation experiments, leads to the formation of an icosahedral structure. The molecular dynamics simulation experiments demonstrate the possibility of controlling the formation of a structure of nickel nanoclusters during crystallization.