Jurkonis R., Sakalauskas A., Lukoševičius A., Maciulevičius M., Tamoši~-unas M., Šatkauskas S. «Mapping Microbubble and Ultrasound Spatio-temporal Interaction by M-mode Imaging: The Study of Feasibility» Акустический журнал, 65, № 2, с. pp. 216-225 (2019)

Ultrasound (US) and microbubble (MB) interaction is an important factor in the research of bioacoustics, as well as targeted drug and gene delivery. In this study, we demonstrate the feasibility of pulse–echo M-mode imaging system to be used for the visualization and quantification of US–MB interaction in both spatial and temporal dimensions. The system incorporates an exposure chamber with the cell–MB suspension, a 2.7 MHz focused US transducer, a US pulser–receiver and the customized LabView software. The results of cell and MB interaction obtained after M-mode image analysis have showed the US–MB interaction to be non-uniform in space and non-stationary in time. In order to quantify the spatio-temporal US–MB interaction, we have introduced the time function of spatial homogeneity dynamics. We have observed that the effective duration of interaction can be characterized at the predefined threshold of spatial homogeneity. For example, at the US excitation of 360 kPa peak negative pressure (15 bursts transmitted at 80 Hz pulse repetition frequency), the US–MB interaction persists for more than 5 seconds in the range at 4 mm depth of the exposure chamber with more than 50% of homogeneity. The system proposed in this assay is feasible for the characterization of US–MB interaction and can be exploited to optimize the MB concentration and/or the US excitation parameters.

Sahin Timur, Dervisoglu Ahmet «High resolution optical spectroscopy of a B-type abundance standard candidate in Ori OB1 – HD 35039» Письма в Астрономический журнал: Астрономия и космическая физика, 45, № 8, с. 585 (2019)

We present LTE analysis of high resolution optical spectra for the B-type abundance standard candidate HD 35039 (HR 1765, 22 Ori) with an ambigous binary nature. The spectra were obtained with the 3.9-m Anglo-Australian Telescope (AAT) and the UCLES spectrograph.

Jurkonis R., Sakalauskas A., Lukoševičius A., Maciulevičius M., Tamoši~-unas M., Šatkauskas S. «Mapping Microbubble and Ultrasound Spatio-temporal Interaction by M-mode Imaging: The Study of Feasibility» Акустический журнал, 65, № 2, с. pp. 216-225 (2019)

Ultrasound (US) and microbubble (MB) interaction is an important factor in the research of bioacoustics, as well as targeted drug and gene delivery. In this study, we demonstrate the feasibility of pulse–echo M-mode imaging system to be used for the visualization and quantification of US–MB interaction in both spatial and temporal dimensions. The system incorporates an exposure chamber with the cell–MB suspension, a 2.7 MHz focused US transducer, a US pulser–receiver and the customized LabView software. The results of cell and MB interaction obtained after M-mode image analysis have showed the US–MB interaction to be non-uniform in space and non-stationary in time. In order to quantify the spatio-temporal US–MB interaction, we have introduced the time function of spatial homogeneity dynamics. We have observed that the effective duration of interaction can be characterized at the predefined threshold of spatial homogeneity. For example, at the US excitation of 360 kPa peak negative pressure (15 bursts transmitted at 80 Hz pulse repetition frequency), the US–MB interaction persists for more than 5 seconds in the range at 4 mm depth of the exposure chamber with more than 50% of homogeneity. The system proposed in this assay is feasible for the characterization of US–MB interaction and can be exploited to optimize the MB concentration and/or the US excitation parameters.

Semenenko V.P. «A brief history of the department of cosmoecology and cosmic mineralogy (to 50-anniversary of M. P. Semenenko institute of geochemistry, mineralogy and ore formation NAS of Ukraine)» Геофизический журнал, 41, № 2, с. 182-193 (2019)

Рассмотрена история зарождения и развития в Украине минералогических исследований космических образцов, главным образом, метеоритов, а также основные этапы становления отдела космоэкологии и космической минералогии в Институте геохимии, минералогии и рудообразования им. Н.П. Семененко и Институте геохимии окружающей среды НАН Украины. Показано, что основы минералогических и химических исследований метеоритов, а также их сбора и коллекционирования в Украине еще в 1930-х годах заложил академик В.И. Вернадский. С 1969 г. минералогические исследования метеоритов проводились во Львовском университете, а космохимические – в Институте геохимии и физики минералов АН Украины. Организаторами и идеологами этих исследований были академики Н.П. Семененко, Е.К. Лазаренко, Э.В. Соботович, доцент А.А. Ясинская. В 1987 г. Э.В. Соботович реализовал идею Е.К. Лазаренко и создал в отделе ядерной геохимии и космохимии лабораторию космической минералогии, которая со временем была трансформирована в отдел космоэкологии и космической минералогии. Приведены данные о главных этапах развития отдела, его основных научных направлениях, важнейших результатах изучения космического вещества. Отмечена важность поддержки отдела известными научными центрами Запада, а также проведения совместных с ними научно-исследовательских проектов, реализованных на современной инструментальной базе. Отдельно акцентировано внимание на экспедиционных работах отдела по сбору метеоритов, перспективах их изучения, обозначены современные проблемы, связанные с ограниченными возможностями коллекционирования космических образцов прецизионным уровнем исследования и влиянием политико-социальных катастроф на развитие фундаментальной науки.

Sharma Gaurav, Kumar Sushil, Singh Vivek «Design of Si–SiO₂ phoxonic crystal having defect layer for simultaneous sensing of biodiesel in a binary mixture of diesel through optical and acoustic waves» Акустический журнал, 63, № 2, с. pp. 158-167 (2017)

The potentiality of a phoxonic crystal for sensing of biodiesel in a binary mixture of diesel and biodiesel is theoretically investigated. Using the transfer matrix method, the transmission of acoustic and optical waves through a periodic one-dimensional crystal of Si–SiO₂ layers is studied. A pass band is created in the band gap region by introducing a cavity in the considered one-dimensional crystal structure. This pass band can also be considered as a defect mode, and it is found that its position is highly dependent on mole concentration of binary mixture of biodiesel and diesel present in the cavity. The sensitivity of the sensor for a binary mixture of biodiesel and diesel in the cavity with various mole concentrations is estimated. Simulated results provide a valuable guidance for designing a phoxonic crystal sensor consisting of a defect layer.

Li H.X., Tao C.H., Goloshubin G., Liu C., Shi S.H., Huang G.N., Zhang H., Zhang J., Zhang X.F. «A Modified Biot/Squirt Model of Sound Propagation in Water-Saturated Sedment» Акустический журнал, 64, № 4, с. pp. 453-458 (2018)

A modified Biot/Squirt flow model was developed. The difference between MBISQ and BISQ models is the expression for the porosity differential. Numerical analysis shows that the acoustic dispersion predicted by MBISQ is much higher than by BISQ. Investigations of the effects of permeability, viscosity, and squirt flow length on velocity and attenuation indicate that the behavior of MBISQ agrees with that of the BISQ model. The result of sediment acoustic inversion based on MBISQ was more reasonable than the result of BISQ model.

Li Jiake, Chen Xiaodong, Wang Yi, Shi Yifeng, Yu Daoyin «Generalized sidelobe canceler beamforming applied to medical ultrasound imaging» Акустический журнал, 63, № 2, с. pp. 229-236 (2017)

A generalized sidelobe canceler (GSC) approach is proposed for medical ultrasound imaging. The approach uses a set of adaptive weights instead of traditional non-adaptive weights, thus suppressing the interference and noise signal of echo data. In order to verify the validity of the proposed approach, Field II is applied to obtain the echo data of synthetic aperture (SA) for 13 scattering points and circular cysts. The performance of GSC is compared with SA using boxcar weights and Hamming weights, and is quantified by the full width at half maximum (FWHM) and peak signal-to-noise ratio (PSNR). Imaging of scattering point utilizing SA, SA (hamming), GSC provides FWHMs of 1.13411, 1.68910, 0.36195 mm and PSNRs of 60.65, 57.51, 66.72 dB, respectively. The simulation results of circular cyst also show that GSC can perform better lateral resolution than non-adaptive beamformers. Finally, an experiment is conducted on the basis of actual echo data of an ultrasound system, the imaging result after SA, SA (hamming), GSC provides PWHMs of 2.55778, 3.66776, 1.01346 mm at z=75.6 mm, and 2.65430, 3.76428, 1.27889 mm at z=77.3 mm, respectively.

Wang Ping, Shi Yizhe, Jiang Jinyang, Kong Lu, Gong Zhihui «Generalized Sidelobe Canceller for Ultrasound Imaging based on Eigenvalue Decomposition» Акустический журнал, 65, № 1, с. pp. 123-131 (2019)

The improved generalized sidelobe canceller (GSC) based on eigenvalue decomposition beamforming technique for ultrasound imaging is proposed. Firstly, the signal subspace is obtained by performing eigenvalue decomposition on the covariance matrix of received data. Secondly, the weighting vector of GSC is divided into adaptive and non-adaptive two parts. Then the non-adaptive part is projected into the signal subspace to obtain a new steer vector. Subsequently, based on the orthogonal complementary space of the new steer vector, the blocking matrix is constructed. Finally, the weighting vector is updated by projecting the final weighting vector into the signal subspace. In order to verify the proposed algorithm, the simulations of the point targets and the cyst phantom were conducted in Field II. The experimental results indicate that the proposed method has better resolution and contrast ratio than the conventional algorithms. In addition, the algorithm is robust to noises. Furthermore, combining with coherence factor, the contrast ratio of the proposed algorithm can be further improved in comparison with a conventional GSC with coherence factor.

Tyagi Kapil Dev, Kumar Arun, Bahl Rajendar, Singh Karmjeet «Experimental measurement of acoustic properties in snow» Акустический журнал, 63, № 3, с. 297-301 (2017)

This paper presents the results of field experiments done for the measurement of attenuation constant and speed of sound in the snow medium. The field experiments were conducted at two locations corresponding to relatively dry and wet snow. The main objective of our method is to overcome the potential limitations of the other methods. There are two major concerns: one is sound signal leakage and the other is the measurement need to be done within a same layer of snowpack. The ref lections from the boundaries will affect the measurements. In our experiments the transducers are kept far from the snowpack boundaries, so that there will be no likelihood of strong ref lected signals from the boundaries. These issues have not been addressed by the other researchers. This work adds to the measurement results of the attenuation constant and speed of sound in snow that are available in the research literature. It is found that sound signal attenuation greatly depends on the frequency of sound signal and wetness of snow.

Sharma Gaurav, Kumar Sushil, Singh Vivek «Design of Si–SiO₂ phoxonic crystal having defect layer for simultaneous sensing of biodiesel in a binary mixture of diesel through optical and acoustic waves» Акустический журнал, 63, № 2, с. pp. 158-167 (2017)

The potentiality of a phoxonic crystal for sensing of biodiesel in a binary mixture of diesel and biodiesel is theoretically investigated. Using the transfer matrix method, the transmission of acoustic and optical waves through a periodic one-dimensional crystal of Si–SiO₂ layers is studied. A pass band is created in the band gap region by introducing a cavity in the considered one-dimensional crystal structure. This pass band can also be considered as a defect mode, and it is found that its position is highly dependent on mole concentration of binary mixture of biodiesel and diesel present in the cavity. The sensitivity of the sensor for a binary mixture of biodiesel and diesel in the cavity with various mole concentrations is estimated. Simulated results provide a valuable guidance for designing a phoxonic crystal sensor consisting of a defect layer.

Naserabadi M.J.Ranjbar, Sodagar S. «Ultrasonic high frequency lamb waves for evaluation of plate structures» Акустический журнал, 63, № 4, с. pp. 402-409 (2017)

The potentials of high frequency Lamb wave modes are investigated in the inspection of plate-like structures. The wave propagation characteristics of higher order wave modes and the corresponding sensitivity and detectability are studied. Finite element simulations are carried out using infinite elements to model the ultrasonic wedge transducer and the inspection system. Experimental pulse–echo measurements are conducted to verify the influence of different modes characteristics predicted from the finite element simulations. The experimental measurements show a good agreement with the obtained numerical results for the fundamental modes, S₀ and A₀, and the higher order modes, S₁ and A₁, at 4 MHz mm of frequency–thickness.

Huo Shao-Yong, Chen Jiu-Jiu, Song Guang-Huang, Han Xu «Asymmetric propagation of the first order antisymmetric lamb wave in a tapered plate based on time domain analysis» Акустический журнал, 63, № 4, с. pp. 393-401 (2017)

The asymmetric propagation of the first order antisymmetric (A₁) Lamb wave in a tapered plate respectively carved with sharp bottom corner and round bottom corner is theoretically investigated. Through numerical simulation of A₁ Lamb wave in time domain, we find that when the thickness of the waveguide abruptly decreases to below the cut-off thickness, about half of the A₁ mode is converted into the fundamental symmetrical S₀ and antisymmetrical A₀ modes to pass through the defected region. Furthermore, the transmitted modes A₀ and S₀ are completely apart from each other and can be quantitatively evaluated. Conversely, when the thickness change is very smooth, most of the energy of A₁ Lamb wave is reflected back. It is the unique mode conversion behavior that leads to great transmission difference value of A₁ Lamb wave along the opposite directions. Finally, the influence of geometrical parameters on the transmission coefficient is also studied. The higher efficiency and proper working frequency range can be realized by adjusting the slope angle τ, height h₁ and h₂. The simple asymmetric systems will be potentially significant in applications of ultrasound diagnosis and therapy.

Soumya Roy, Prasad A., Panja S.Ch., Ghosh K., Patra S.N. «A search for periodicities in F10.7 solar radio flux data» Астрономический вестник. Исследования Солнечной системы, 53, № 3, с. 240 (2019)

The radio frequency emission at 10.7 cm (or 2800 MHz) wavelength (considered as solar flux density) out of different possible wavelengths is usually selected to identify periodicities because of its high correlation with solar extreme ultraviolet radiation as well as its complete and long observational record other than sunspot related indices. The solar radio flux at 10.7 cm wavelength plays a very valuable role for forecasting the space weather because it is originated from lower corona and chromospheres region of the Sun. Also, solar radio flux is a magnificent indicator of major solar activity. Here in the present work the solar radio flux data from 1965 to 2014 observed at the Domimion Radio Astrophysical Observatory in Penticton, British Columbia has been processed using Date Compensated Discrete Fourier Transform (DCDFT) to identify predominant periods within the data along with their confidence levels. Also, the multi-taper method (MTM) for periodicity analysis is used to validate the observed periods. Present investigation exhibits multi-periodicity of the time series F10.7 solar radio flux data around 27, 57, 78, 127, 157, 4096 days etc. The observed periods are also compared with the periods of MgII Index data using same algorithm as MgII Index data has 99.9% correlation with F10.7 Solar Radio Flux data. It can be observed that the MgII index data exhibits similar periodicities with very high confidence levels. Present investigation also clearly indicates that the computed results are very much confining with the results obtained in different communications for the similar data of 10.7 cm Solar Radio Flux as well as for the other solar activities.

Guan Shane, Southall Brandon L., Vignola Joseph F., Judge John A., Turo Diego «Sonar inter-ping noise field characterization during cetacean behavioral response studies off Southern California» Акустический журнал, 63, № 2, с. 204-215 (2017)

The potential negative effects of sound, particularly active sonar, on marine mammals has received considerable attention in the past decade. Numerous behavioral response studies are ongoing around the world to examine such direct exposures. However, detailed aspects of the acoustic field (beyond simply exposure level) in the vicinity of sonar operations both during real operations and experimental exposures have not been regularly measured. For instance, while exposures are typically repeated and intermittent, there is likely a gradual decay of the intense sonar ping due to reverberation that has not been well described. However, it is expected that the sound field between successive sonar pings would exceed natural ambient noise within the sonar frequency band if there were no sonar activity. Such elevated sound field between the pings may provide cues to nearby marine mammals on source distances, thus influencing potential behavioral response. Therefore, a good understanding of the noise field in these contexts is important to address marine mammal behavioral response to MFAS exposure. Here we investigate characteristics of the sound field during a behavioral response study off California using drifting acoustic recording buoys. Acoustic data were collected before, during, and after playbacks of simulated mid-frequency active sonar (MFAS). An incremental computational method was developed to quantify the inter-ping sound field during MFAS transmissions. Additionally, comparisons were made between inter-ping sound field and natural background in three distinctive frequency bands: low-frequency (<3 kHz), MFA-frequency (3–4.5 kHz), and high-frequency (>4.5 kHz) bands. Results indicate significantly elevated sound pressure levels (SPLs) in the inter-ping interval of the MFA-frequency band compared to natural background levels before and after playbacks. No difference was observed between inter-ping SPLs and natural background levels in the low- and high-frequency bands. In addition, the duration of elevated inter-ping sound field depends on the MFAS source distance. At a distance of 900–1300 m from the source, inter-ping sound field at the exposure frequency is observed to remain 5 dB above natural background levels for approximately 15 s, or 65%, of the entire inter-ping interval. However, at a distance of 2000 m, the 5 dB elevation of the inter-ping SPLs lasted for just 7 s, or 30% of the inter-ping interval. The prolonged elevation of sound field beyond the brief sonar ping at such large distances is most likely due to volume reverberation of the marine environment, although multipath propagation may also contribute to this.

Khalatnikov I.M., Kamenshchik A.Yu., Starobinsky A.A. «Quasi-isotropic expansion for a two-fluid cosmological model containing radiation and string gas» Журнал экспериментальной и теоретической физики, 156, № 4, с. 581-584 (2019)

Extended Abstract. The full text of this paper is published in the English version of JETP.

Su Ting, Zhang Shi, Li Dayu, Yao Dingjie «Combined Sign Coherent Factor and Delay Multiply and Sum Beamformer for Plane Wave Imaging» Акустический журнал, 64, № 3, с. pp. 379-386 (2018)

Plane wave imaging is a relatively new technique in ultrasound imaging. However, in traditional methods, the coherent information of different emissions and different elements are not considered. In fact, the sign coherent factor (SCF) can improve the lateral resolution of the imaging greatly. In addition, the delay multiply and sum (DMAS) beamformer is mainly based on the spatial correlation of background scattering signals, it has higher contrast and resolution, but suffers from energy loss at great depths. In this paper, combining the advantages of SCF and DMAS, the sign coherent factor delay multiply and sum (SCF-DMAS) beamformer for plane wave imaging is proposed. Unlike the traditional plane wave imaging, the proposed SCF-DMAS beamformer is based on the 2-D echo data set, which improves the imaging speed greatly. Finally, we simulated the point targets and the cyst phantom to evaluate the performance of proposed method. Compared with the traditional plane wave imaging, the lateral resolution of SCF-DMAS beamformer improves greatly for the point targets, and for the cyst phantom the contrast ratio (CR) and contrast-to-noise ratio (CNR) increased by 96.97 and by 79.98% respectively without reducing the frame rate.

Sun Fei, Guo Shuwei, Li Borui, Liu Yichao, He Sailing «An Acoustic Metamaterial Lens for Acoustic Point-to-Point Communication in Air» Акустический журнал, 65, № 1, с. pp. 1-6 (2019)

Acoustic metamaterials have become a novel and effective way to control sound waves and design acoustic devices. In this study, we design a 3D acoustic metamaterial lens (AML) to achieve point-to-point acoustic communication in air: any acoustic source (a speaker) in air enclosed by such an AML can produce an acoustic image where the acoustic wave is focused (the field intensity is at a maximum, and the listener can receive the information), while the acoustic field at other spatial positions is low enough that listeners can hear almost nothing. Unlike a conventional elliptical reflective mirror, the acoustic source can be moved around inside our proposed AML. Numerical simulations are given to verify the performance of the proposed AML.

Milekhina O.N., Nechaev D.I., Supin A.Ya. «Frequency Range of Compression for Discrimination of Acoustic Signals with Complex Spectra» Акустический журнал, 65, № 1, с. pp. 96-102 (2019)

Psychophysical experiments on listeners with normal hearing were conducted to discriminate the rippled spectra of an acoustic signal against maskers with different positions of the spectral band relative to the signal band. As the signal level changed from 50 to 80 dB SPL, the on-frequency masker level changed by 29 dB, whereas the low-frequency masker level (the position of the center of the spectral band was from –1.25 to –1 octave relative to the signal) changed by 8.7–9.8 dB. These results are interpreted as 0.3 dB/dB compression of responses to the signal and no compression of the effect of low-frequency maskers. If the spectral bands of the signal and masker partially overlap, discrimination of the spectral structure occurs predominantly in the part of the spectrum that does not overlap the masker spectrum and is subjected to low-frequency masking that is not compressed.