Российский фонд
фундаментальных
исследований

Физический факультет
МГУ им. М.В.Ломоносова
 

J

Ji Xiaojun

 

Fan Yanping, Ji Xiaojun «A Novel Rotation Speed Measurement Method Based on Surface Acoustic Wave» Акустический журнал, 64, № 1, с. pp. 122-128 (2018)

This paper presents an original passive wireless rotation speed measurement method based on surface acoustic wave (SAW) technology. A theoretical analysis was conducted on the principle of SAW rotation speed measurement and a numerical analysis on the SAW response energy pulses with different rotation angles and resonance frequencies was performed. Numerical calculation results showed that when the distance and the effective length of the antenna connected to SAWR vary with the rotation angle, the energy of acquired SAW response varies periodically. The rotation speed was estimated by searching the crossing points of the SAW response energy pulses and its mean value line. The SAW rotation speed measurement system was set up and the high performance SAW resonators were fabricated on a quartz substrate. The proposed measurement system was tested with a maximum error of 0.6 rpm, indicating that the system is capable of measuring rotation speeds from 10 to 100 rpm. Experimental results verified the validity and feasibility of presented rotation speed measurement method.

Акустический журнал, 64, № 1, с. pp. 122-128 (2018) | Рубрика: 06.13

Jia Bing

 

Jia Bing, Wei Jian-Ping, Wen Zhi-Hui, Wang Yun-Gang, Jia Lin-Xing «The experimental research on response characteristics of coal samples under the uniaxial loading process» Акустический журнал, 63, № 6, с. pp. 716-722 (2017)

In order to study the response characteristics of infrasound in coal samples under the uniaxial loading process, coal samples were collected from GengCun mine. Coal rock stress loading device, acoustic emission tested system and infrasound tested system were used to test the infrasonic signal and acoustic emission signal under uniaxial loading process. The tested results were analyzed by the methods of wavelet filter, threshold denoise, time–frequency analysis and so on. The results showed that in the loading process, the change of the infrasonic wave displayed the characteristics of stage, and it could be divided into three stages: initial stage with a certain amount infrasound events, middle stage with few infrasound events, and late stage gradual decrease. It had a good consistency with changing characteristics of acoustic emission. At the same time, the frequency of infrasound was very low. It can propagate over a very long distance with little attenuation, and the characteristics of the infrasound before the destruction of the coal samples were obvious. A method of using the infrasound characteristics to predict the destruction of coal samples was proposed. This is of great significance to guide the prediction of geological hazards in coal mines.

Акустический журнал, 63, № 6, с. pp. 716-722 (2017) | Рубрика: 09.01

Jia Lin-Xing

 

Jia Bing, Wei Jian-Ping, Wen Zhi-Hui, Wang Yun-Gang, Jia Lin-Xing «The experimental research on response characteristics of coal samples under the uniaxial loading process» Акустический журнал, 63, № 6, с. pp. 716-722 (2017)

In order to study the response characteristics of infrasound in coal samples under the uniaxial loading process, coal samples were collected from GengCun mine. Coal rock stress loading device, acoustic emission tested system and infrasound tested system were used to test the infrasonic signal and acoustic emission signal under uniaxial loading process. The tested results were analyzed by the methods of wavelet filter, threshold denoise, time–frequency analysis and so on. The results showed that in the loading process, the change of the infrasonic wave displayed the characteristics of stage, and it could be divided into three stages: initial stage with a certain amount infrasound events, middle stage with few infrasound events, and late stage gradual decrease. It had a good consistency with changing characteristics of acoustic emission. At the same time, the frequency of infrasound was very low. It can propagate over a very long distance with little attenuation, and the characteristics of the infrasound before the destruction of the coal samples were obvious. A method of using the infrasound characteristics to predict the destruction of coal samples was proposed. This is of great significance to guide the prediction of geological hazards in coal mines.

Акустический журнал, 63, № 6, с. pp. 716-722 (2017) | Рубрика: 09.01

Jiang Jinyang

 

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.

Акустический журнал, 65, № 1, с. pp. 123-131 (2019) | Рубрика: 12.05

Jin S.J.

 

Ding S.S., Jin S.J., Luo Z.B., Chen J., Lin L. «Researches on the ultrasonic scattering attenuation of carbon fibre reinforced plastics with 2D real morphology void model» Акустический журнал, 63, № 4, с. pp. 490-495 (2017)

In order to investigate the ultrasonic propagation in carbon fibre reinforced plastics with complex void morphology, the effective mathematical model needs to be established. The current models are oversimplified on void morphology, leading to the significant inconsistency of theoretical calculation with experimental results. In view of the problem, a real morphology void model (RMVM) was established with the idea of image-based modeling. The void morphology was extracted by digital image processing technology, and the material properties were assigned subsequently. As a result of the complex and random void morphology in RMVMs, a non-unique corresponding relationship was verified between porosity P and ultrasonic attenuation coefficient α. In the scatterplot of simulation, about 66 percent of points were plotted within the ±10% error band of fitting line, while almost all the data located at the ±20% error zone. The simulation results showed good consistency with experiments, and it proved the validity of RMVM. The investigation provides a novel model to explore the ultrasonic scattering mechanism for the composite materials containing random voids.

Акустический журнал, 63, № 4, с. pp. 490-495 (2017) | Рубрика: 06.02

Ju Luyan

 

Li Suobin, Dou Yihua, Chen Tianning, Wan Zhiguo, Ju Luyan, Zhang Fan, Cui Xiao Xiao «Forming Low-Frequency Complete Vibration Bandgaps in a thin Nonmetallic Elastic Metamaterial Plate» Акустический журнал, 65, № 3, с. pp. 322-333 (2019)

Low-frequency vibration-bandgaps in elastic metamaterials open new possibilities to minimize low-frequency vibration and noise. Unfortunately, fabricating a complete vibration bandgap for low frequencies still represents a challenging engineering task. In this paper, a new type of a low-frequency complete vibration bandgap in a thin non-metal elastic metamaterial plate is introduced and investigated numerically. The proposed elastic metamaterial plate consists of decoupling-resonators, which are deposited on a 2D, locally resonant phononic-crystal plate, made of an array of rubber fillers, which are embedded in a nonmetallic plate. The dispersion relationship, the power-transmission spectrum, and the displacement fields for the eigenmode are calculated using the finite element method. It is shown that coupling between the local resonance mode of the decoupling-resonators and the Lamb-wave mode of the epoxy plate, consistent with the modal superposition principle, is responsible for the formation of vibration bandgaps. Moreover, the equivalent spring-mass system for the coupling-resonators can be decoupled by introducing a rubber filler. In addition, both longitudinal and the transverse elastic wave bandgaps can be tuned to the same low-frequency range. As a result, a novel kind of low-frequency complete vibration bandgap, which can damp a low-frequency elastic wave, is produced. Furthermore, the effects of the decoupling-resonators on the vibration bandgap are investigated. It is now possible that an elastic metamaterial plate can be dampen with complete low-frequency vibration bandgaps, which can potentially be used for commercial noise and vibration reduction.

Акустический журнал, 65, № 3, с. pp. 322-333 (2019) | Рубрика: 06.15

Judge John A.

 

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.

Акустический журнал, 63, № 2, с. 204-215 (2017) | Рубрика: 13.01

Jurkonis R.

 

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.

Акустический журнал, 65, № 2, с. pp. 216-225 (2019) | Рубрика: 13.04