The article considers the question of auditory perception of speech and piano sounds, which have a relatively weak fundamental tone level against the background of high harmonics (formants of the vocal cords and string overtones, respectively). It is shown that the audible spectrum of these sounds is the spectrum of the interference envelope of the corresponding harmonics. This spectrum contains the fundamental tone as the dominant sound, which is clearly heard in speech and music, while the formants and overtones, initially dominant in the sound spectrum of speech and music, primarily influence the timbre of the fundamental tone. At the level of hypothesis, it is suggested that the interference envelope is detected as a result of the sound propagation in the nonlinear fluid medium of the cochlea of the inner ear.

The issue of auditory perception of speech and piano sounds, which have a relatively weak fundamental tone level against the background of high harmonics (formants of the vocal cords and string overtones, respectively), is considered. It is shown that the audible spectrum of these sounds is the spectrum of the interference envelope of oscillations of the corresponding harmonics. This spectrum contains the fundamental tone as the dominant sound, which is clearly heard in speech and music, while the formants and overtones, initially dominant in the sound spectrum of speech and music, primarily affect the timbre of the fundamental tone. At the hypothesis level, it is indicated that the vibration interference envelope is isolated (detected) as a result of the propagation of sound waves in the nonlinear fluid medium of the cochlea of the inner ear.

The book considers the riverine paleostructures of the coastal marine zone from the point of view of marine bottom seismoacoustics

For a better understanding of the peculiarities of the fluvial paleo-structures of the shelf zone, let us briefly dwell on the structure of the terrestrial river structures.

Let us briefly consider the main properties of the seafloor in the shelf zone.

As follows from the above, in terms of structural geomorphology, bathymetry and seismic-stratigraphy, paleo-channels have characteristic features that distinguish them from other shelf seabed structures.

Let us consider in more detail the seismic-acoustic profiles of land river beds.

Curves of equal loudness for sounds of different frequencies and auditory frequency responses are discussed. It is shown that curves of equal loudness do not describe the auditory frequency response and are applicable only to tonal signals. The auditory frequency response can adapt to the sound spectrum. For music, a broadband frequency response is formed; for speech, a frequency response with low-frequency suppression is used.

Let us briefly consider the design of a bottom seismic-acoustic profiler.

The effect of a significant (up to 20 dB) decrease in the audibility level of low-frequency piano sounds (accompaniment in the bass register) against a background of high-frequency sounds (melody) when music is played at a fast tempo was discovered and investigated. This indicates that the performance tempo of a piece significantly affects a listener’s perception of the sound sequence of a piece of music. The effect is explained based on an analysis of the physical characteristics of sound formation in a grand piano depending on the performance tempo and perception of sounds by the human ear. The effect is clearly demonstrated by the example of performance of the first movement (allegro di molto e con brio) of Beethoven’s Sonata No. 8 in C minor (Pathetique).

Abstract—Design and fabrication of photosensitive array elements in the 384 × 288 element format with a step of 25 μm with a long wavelength limit of sensitivity at 0.5 to approximately 9.5 μm were performed. The circuit and topology were developed, according to which matrix high-speed multiplexers are manufactured in the form of 384 × 288 elements with a step of 25 microns, which provide operating modes at a clock frequency of up to 20 MHz. The 384 × 288 element hybrid photodetector (PD) format in 25 μm increments has an average Noise Equivalent Temperature Difference (NETD) of less than 30 mK, while the number of working elements was more than 97%. Examples are given of using the microscanning system to reduce defective pixels in an image frame and/or increase the frame format to 768 × 576. It is shown that as a result of the use of microscans in a thermal imaging channel based on the developed PD during the transition to the 768 × 576 format, an improvement in spatial resolution of 1.4 times was obtained for the same minimum resolved temperature difference (MRTD), while the MRTD at a frequency of 0.44 mrad-1 decreased from 1.6 to 0.9 K compared to the original 384 × 288 format.

Для ряда приборов, особенно оптико-электронных, работа которых основана на применении современных, прежде всего матричных, приемников излучения, чувствительных в видимой и в ИК-области спектра, задача анализа влияния изменения температуры на параметры оптических систем, а следовательно и на выходные параметры этих приборов, представляется вполне актуальной.Приведены соотношения, определяющие положение и размер изображения при термобарическом изменении показателей преломления материала линз оптической системы.Показано, что на положение линзы при опоре ее преломляющей поверхности на базовую поверхность торца оправы или корпуса существенно большее влияние оказывают вызванные колебаниями температуры изменения диаметра окружности соприкосновения контактирующих деталей, чем изменения формы поверхности оптической детали

Recent processing of earlier obtained experimental data has revealed two phenomena making it possible to obtain necessary and sufficient conditions for detecting a forward scattering signal with the best efficiency. The location object should intersect one of the rays connecting the emitter and the receiver without touching the water surface. This is the basis of the first phenomenon: significant (more than 100-fold) compression of the detected signal. The second phenomenon is that the noise background surrounding the detected signal is a type of noise formed by an uneven bottom relief. This noise does not generate false alarms and is physically similar to speckle noise in optics. It is demonstrated that additive noise is primarily formed by signals scattered by a rough lake surface and that this noise is weakly suppressed when detecting the useful signal; however, it can be eliminated by imparting directivity to the illuminating signal source. All other noise is completely suppressed.

A way of using forward scattering to form images of a moving scatterer (MS) along its entire motion path is proposed and achieved in a full-scale experiment. Previously, this was done at the point where the MS signal was maximum, since the signal level during the MS’s movement decreased in accordance with its radiation directivity at a constant interference level. In the proposed MS signal detection method, a horizontal array is used in a different way, so that interference also decreases in accordance with the directivity of the horizontal array. This creates conditions for the formation of the signal of a passing MS, the form of which the interference can neither receive nor mask. The method was successfully applied in a full-scale experiment in 1998.

The aberration requirements for refractive compensators in autocollimator systems used to monitor second-order concave aspherical surfaces are determined from the underlying principles of optical system design. The aberration properties of the refractive elements were taken into account in determining the functional contribution of each element to achieve the desired results. The results of this paper can be used as a scientific foundation for optimization of prefocal and postfocal optical compensation systems for a variety of specific applications.

It is shown that supplementing an afocal aberration-free Mersenne system with interchangeable mirror objectives and mirror-lens objectives makes it possible to obtain a number of optical systems for a compact objective of a high-aperture telescope that form an image that possesses aplanatic, anastigmatic, and plananastigmatic correction of aberrations with the required relative aperture. The length of the system in this case is about a factor of four less than the diameter of its entrance pupil. (C) 2017 Optical Society of America

The results of the analysis of dimensions and aberration properties of an optical system with three thin components, which is equivalent to an optical system consisting of three reflecting surfaces without an intermediate image, are presented. An engineering method for designing optical systems of a three-mirror flat-field anastigmat (plananastigmat) optical system was developed and described. (c) 2018 Optical Society of America

Using the example of an ellipsoid of revolution, a mathematical analysis of a scheme used to shape second-order non-spherical surfaces by the method of linear contact was performed. It is shown that the method of linear contact does not make it possible to lap along a line when processing a number of non-spherical surfaces. In particular, the method is only applicable within the limits of permissible changes in the eccentricity of the generatrix. (C) 2017 Optical Society of America