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  • Comparative Studies. Non-European Languages/Literatures  (5)
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  • Comparative Studies. Non-European Languages/Literatures  (5)
RVK
  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2016
    In:  The Journal of the Acoustical Society of America Vol. 140, No. 3 ( 2016-09-01), p. 1739-1748
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 140, No. 3 ( 2016-09-01), p. 1739-1748
    Abstract: Identification and measurement of moving sound sources are the bases for vehicle noise control. Acoustic holography has been applied in successfully identifying the moving sound source since the 1990s. However, due to the high demand for the accuracy of holographic data, currently the maximum velocity achieved by acoustic holography is just above 100 km/h. The objective of this study was to establish a method based on the complete Morse acoustic model to restore the measured signal in high-speed situations, and to propose a far-field acoustic holography method applicable for high-speed moving sound sources. Simulated comparisons of the proposed far-field acoustic holography with complete Morse model, the acoustic holography with simplified Morse model and traditional delay-and-sum beamforming were conducted. Experiments with a high-speed train running at the speed of 278 km/h validated the proposed far-field acoustic holography. This study extended the applications of acoustic holography to high-speed situations and established the basis for quantitative measurements of far-field acoustic holography.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2016
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3362-3362
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3362-3362
    Abstract: Around 300 bat species are known to emit their ultrasonic biosonar pulses through the nostrils. This nasal emission coincides with the presence of intricately shaped baffle structures surrounding the nostrils. Some prior experimental evidence indicates that these “noseleaves” have an effect on the shape of the animals' radiation patterns. Here, a numerical acoustical analysis of the noseleaf of a slit-faced bat species is presented to show that all three distinctive parts of its noseleaf (“pit”, “upper leaf”, “lower leaf”) have an effect on the acoustic near field as well as on the directivity pattern. In their effects on the near field, the noseleaf parts showed a tendency toward spatial partitioning with the effects due to each part dominating a certain region. However, interactions between the acoustic effects of the parts were also evident, most notably, a synergism between the frequency-dependent effects of two parts of the noseleaf (“pit”, “lower leaf”) to produce an even stronger frequency selectivity. supported by the Natural Science Foundation of China (Project No. 10974222), and the China Postdoctoral Science Foundation funded project (No. 20090450599). Bat specimen provided by the School of Physics, Shandong University, China.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3463-3463
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3463-3463
    Abstract: Ultrasonic echoes contain ample flaw information in nondestructive testing. However, bad coupling or small flaw often leads to low SNR (signal-to-noise ratio), so the result provided by conventional amplitude detection may not be accurate enough. To solve this problem, the finite element method is used to investigate the frequency domain characteristics of flaw echoes. Furthermore, a target-matching method based on the maximum output SNR criteria is proposed. The transducer is excited by a certain electrical signal obtained by adaptive filtering deconvolution algorithm for each flaw, so we get a maximum SNR when the excitation signal and flaw match. This is further verified in ultrasonic test for a series of samples containing different sizes of flat-bottom holes. This work is supported by the National Natural Science Foundation of China (Grant Nos. 10834009, 11074272)
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3462-3462
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3462-3462
    Abstract: The boundary conditions for an interface between two solids are analyzed to model second harmonic generation in a thin elastic adhesive layer. The approximate boundary condition models termed as “nonlinear spring models” are rigorously developed using an asymptotic expansion of the exact solutions in the limit of small ratio of interface layer thickness to wavelength. The applicability of such boundary conditions is analyzed by comparison with exact solutions for ultrasonic wave transmission. Numerical calculation indicate that as the acoustic nonlinearity increases, the model tends to be more accurate, meanwhile the second-harmonic amplitude increases in direct ratio. The present nonlinear spring models may provide a potential to evaluate the nonlinear mechanical behavior of bonding interface. Acknowledgment: This work is supported by the National Natural Science Foundation of China (Grant No.10834009)
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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  • 5
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2008
    In:  The Journal of the Acoustical Society of America Vol. 123, No. 5_Supplement ( 2008-05-01), p. 3407-3407
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 123, No. 5_Supplement ( 2008-05-01), p. 3407-3407
    Abstract: This paper is focusing on the relationship between the natural frequencies of a multilayered system of different isotropic elastic materials and the thickness of each layer. A relevant ultrasonic method for thickness determination of a multilayered system by natural frequencies has been developed. The natural frequencies are numerically calculated from the normally incident reflection coefficient of a "steel-epoxy resin-aluminum-thin polymer" structured lamination. Some natural frequencies are sensitive to one layer thickness in certain range while the others are invariable. This phenomenon is explained by the defined strain energy ratio, and used for our thickness inversion. The measured natural frequencies of a specimen show good agreement with the theoretical ones. All the natural frequencies are taken into account, and the simulated annealing method is employed for the thickness inverse calculation of the multilayered structure. The average relative errors of calculated thickness of the each layer are -0.7%, 35%, -1.3% and -6.1%, corresponding to the real values: 1957μm, 16μm, 1913μm and 54μm.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2008
    detail.hit.zdb_id: 1461063-2
    Location Call Number Limitation Availability
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