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  • English  (28)
  • Comparative Studies. Non-European Languages/Literatures  (28)
  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2019
    In:  The Journal of the Acoustical Society of America Vol. 145, No. 1 ( 2019-01-01), p. EL25-EL29
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 145, No. 1 ( 2019-01-01), p. EL25-EL29
    Abstract: The thickness dependences of acoustic bandgaps were theoretically and experimentally investigated in two-dimensional phononic crystals (PCs) immersed in water. The acoustic pressure transmission coefficients were measured as a function of the PC thickness in order to understand the characteristics of the transmission loss through the PCs. The acoustic bandgaps can be classified into two types of generation mechanisms from the perspective of acoustic diffraction modes: Bragg bandgap and non-zeroth order diffraction (NZOD) bandgap. The NZOD bandgaps show larger transmission losses and shorter decay lengths with increasing PC thickness than the Bragg bandgaps.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2019
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2017
    In:  The Journal of the Acoustical Society of America Vol. 142, No. 4 ( 2017-10-01), p. 2298-2310
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 142, No. 4 ( 2017-10-01), p. 2298-2310
    Abstract: This study proposes an acoustic theory that describes the resonance phenomena in a resonator made of acoustic composite right/left-handed (CRLH) metamaterials, and verifies it through numerical simulation. The established theory for a microwave CRLH metamaterial resonator is adapted to explain the resonance phenomena in an acoustic CRLH metamaterial resonator. In particular, attention is focused on the zeroth-order resonance phenomenon which has several interesting properties. When a resonator is composed of a CRLH metamaterial, a resonance with a flat acoustic field distribution may occur at one of the frequencies where the wavenumber becomes zero. This resonance is called zeroth-order resonance. Through numerical simulation, such unusual resonance phenomenon in acoustics is observed in more detail and the proposed theory is verified. The results of the theory and the numerical simulation clearly show that zeroth-order resonance can exist at those frequencies where the acoustic field distribution is flat due to infinite wavelength. It is also shown that the resonance frequency and the Q factor of this resonance depend on the boundary condition at both ends of the resonator, and they basically do not change even when the number of units is reduced or increased.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2017
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2015
    In:  The Journal of the Acoustical Society of America Vol. 138, No. 5 ( 2015-11-01), p. 2860-2870
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 138, No. 5 ( 2015-11-01), p. 2860-2870
    Abstract: Soundscape is a sound environment that emphasizes the awareness of auditory perception and social or cultural understandings. The case of spatial perception is significant to soundscape. However, previous studies on the auditory spatial perception of the soundscape environment have been limited. Based on 21 native binaural-recorded soundscape samples and a set of auditory experiments for subjective spatial perception (SSP), a study of the analysis among semantic parameters, the inter-aural-cross-correlation coefficient (IACC), A-weighted-equal sound-pressure-level (Leq), dynamic (D), and SSP is introduced to verify the independent effect of each parameter and to re-determine some of their possible relationships. The results show that the more noisiness the audience perceived, the worse spatial awareness they received, while the closer and more directional the sound source image variations, dynamics, and numbers of sound sources in the soundscape are, the better the spatial awareness would be. Thus, the sensations of roughness, sound intensity, transient dynamic, and the values of Leq and IACC have a suitable range for better spatial perception. A better spatial awareness seems to promote the preference slightly for the audience. Finally, setting SSPs as functions of the semantic parameters and Leq-D-IACC, two linear multivariate evaluation models of subjective spatial perception are proposed.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2015
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2023
    In:  The Journal of the Acoustical Society of America Vol. 154, No. 4 ( 2023-10-01), p. 2112-2123
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 154, No. 4 ( 2023-10-01), p. 2112-2123
    Abstract: Acoustic spectroscopy and neural networks (NNs) are applied to on-line real-time measurement of particle size distribution (PSD) during wet milling of pharmaceutical nanocrystals. A method for modeling the relationship between acoustic attenuation spectra and PSD is proposed that is based on NNs and principal component analysis (PCA). PCA reduces the dimensions of both the spectra and the PSD; then, a neural network model of 2 × 2 × 2 (input, hidden, output layer nodes) with only eight connection weights is built. Compared with previous instrument models that could require as many as 14 physical properties, the current approach does not need any prior knowledge of the system's properties. In addition, the time taken to complete a PSD measurement is reduced from minutes to seconds and it always generates a single solution, rather than possible multiple PSD solutions as in early methods. Application to hydrotalcite nanomilling found good agreement between the on-line measurements and off-line analysis.
    Type of Medium: Online Resource
    ISSN: 0001-4966
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2023
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  • 5
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2019
    In:  The Journal of the Acoustical Society of America Vol. 145, No. 3_Supplement ( 2019-03-01), p. 1667-1667
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 145, No. 3_Supplement ( 2019-03-01), p. 1667-1667
    Abstract: High-precision absolute determinations of gravitational acceleration g provide important data for many fields such as metrology, geophysics, and geological exploration. In absolute gravimetry, vibrational noise from seismic and other environmental disturbances is one of the limiting factors. Several types of ultra-low vertical vibration isolators have been developed in Tsinghua University. The first one is a passive isolator based on LaCoste spring linkage and can achieve a natural period up to 32 s. The second one is an active isolator employing a two-stage beam structure. The upper beam is suspended from the frame with a hex spring, and the lower beam is suspended from the upper one using a zero-length spring. A feedback circuit is equipped to keep the angle between the two beams at a fixed value. The isolator can achieve a natural period of 100 s. The last one is an active isolator based on a two-stage structure, in which geometric anti-springs are used to support the proof mass. The volume of the isolator is greatly decreased, and the allowable load is increased while maintaining a natural period more than 15 s.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2019
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2007
    In:  The Journal of the Acoustical Society of America Vol. 121, No. 4 ( 2007-04-01), p. EL137-EL144
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 121, No. 4 ( 2007-04-01), p. EL137-EL144
    Abstract: Experimental observations of the subharmonic and ultraharmonic acoustic waves in water-saturated sandy sediment are reported in this paper. Acoustic pressures of both nonlinear acoustic waves strongly depend on the driving acoustic pressure at a transducer. The first ultraharmonic wave reaches a saturation value as the driving acoustic pressure increases. The acoustic pressure levels of both nonlinear acoustic waves exhibit some fluctuations in comparison with that of the primary acoustic wave as the receiving distance of hydrophone increases in sediment. The subharmonic and the ultraharmonic phenomena in this study show close resemblance to those produced in bubbly water.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2007
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2005
    In:  The Journal of the Acoustical Society of America Vol. 117, No. 4_Supplement ( 2005-04-01), p. 2381-2381
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 117, No. 4_Supplement ( 2005-04-01), p. 2381-2381
    Abstract: Bubble density was estimated with a subharmonic acoustic wave generated in bubbly water. The subharmonic acoustic wave can be easily generated due to the nonlinearity of bubbly water if the frequency of primary acoustic wave is double of the bubble resonance frequency and the driving acoustic pressure amplitude exceeds a certain threshold value. The frequency of primary acoustic wave was varied from 200 kHz to 500 kHz while the bubble resonance radius at subharmonic frequency was from 12 um to 28 um. The pressure level of the subharmonic acoustic wave linearly increased as the driving acoustic pressure amplitude increased. With the subharmonic pressure level, the bubble density was estimated from nonlinear bubble oscillation equation [Yu. A. Ilinskii and E. A. Zabolotskaya, J. Acoust. Soc. Am. 92, 2837–2841 (1992)]. The estimated bubble densities were also compared with those from a linear conventional acoustic bubble sizing method. Bubble sizing with subharmonic acoustic wave seems to be easily utilized for the diagnosis of sandy sediment with bubbles.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2005
    detail.hit.zdb_id: 1461063-2
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  • 8
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2020
    In:  The Journal of the Acoustical Society of America Vol. 147, No. 1 ( 2020-01-01), p. 206-217
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 147, No. 1 ( 2020-01-01), p. 206-217
    Abstract: Noise acceptance is an aspect of indoor soundscape research. While staying or walking in a transport hub, sequential sounds form sequence sounds sessions, which are referred to as an acoustic sequence. The basic phenomenon and effects of acoustic sequences on acceptance evaluations have been explored. A total of 209 sections of 30 s acoustic units were extracted before performing acceptance evaluations. The acoustic units were divided into strong, medium, and weak levels, and compiled into 37 pieces of acoustic sequences, which were then subjected to four tests for acceptance evaluation: sound content, acceptance level, and effects of weak and strong acceptance units. One piece of an acoustic sequence consists of 20 acoustic units. The results show that all acoustic sequences exhibit “attenuation effects”—as for any acoustic unit that makes up the sequence, general acceptance decreases with time. The lower the acceptance, the faster the decay in score. High acceptance units have an “enhancement effect,” and the acceptance increases after a high acceptance unit. Low acceptance units have a “boost effect,” and the acceptance increases after a low-level acceptance. Both enhancement and boost effects could improve the acceptance evaluation of acoustic sequences and sound experiences in transport hubs.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2020
    detail.hit.zdb_id: 1461063-2
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  • 9
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2003
    In:  The Journal of the Acoustical Society of America Vol. 114, No. 4 ( 2003-10-01), p. 2284-2293
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 114, No. 4 ( 2003-10-01), p. 2284-2293
    Abstract: Acoustic wave propagation in bovine cancellous bone is experimentally and theoretically investigated in the frequency range of 0.5–1 MHz. The phase velocity, attenuation coefficient, and broadband ultrasonic attenuation (BUA) of bovine cancellous bone are measured as functions of frequency and porosity. For theoretical estimation, the Modified Biot–Attenborough (MBA) model is employed with three new phenomenological parameters: the boundary condition, phase velocity, and impedance parameters. The MBA model is based on the idealization of cancellous bone as a nonrigid porous medium with circular cylindrical pores oriented normal to the surface. It is experimentally observed that the phase velocity is approximately nondispersive and the attenuation coefficient linearly increases with frequency. The MBA model predicts a slightly negative dispersion of phase velocity linearly with frequency and the nonlinear relationships of attenuation and BUA with porosity. The experimental results are in good agreement with the theoretical results estimated with the MBA model. It is expected that the MBA model can be usefully employed in the field of clinical bone assessment for the diagnosis of osteoporosis.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2003
    detail.hit.zdb_id: 1461063-2
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  • 10
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2007
    In:  The Journal of the Acoustical Society of America Vol. 121, No. 5 ( 2007-05-01), p. 2553-2558
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 121, No. 5 ( 2007-05-01), p. 2553-2558
    Abstract: The frequency-dependent phase velocity and attenuation coefficient for the fast longitudinal wave in a water-saturated sandy sediment were measured over the frequency range from 0.3to1.0MHz. The experimental data of phase velocity exhibited the significant negative dispersion, with the mean rate of decline of 120±20m∕s∕MHz. The Biot model predicted the approximately nondispersive phase velocity and the grain-shearing (GS) model exhibited the slightly positive dispersion. In contrast, the predictions of the multiple scattering models for the negative dispersion in the glass-grain composite were in general agreement with the experimental data for the water-saturated sandy sediment measured here. The experimental data of attenuation coefficient was found to increase nonlinearly with frequency from 0.3to1.0MHz. However, both the Biot and the GS models yielded the attenuation coefficient increasing almost linearly with frequency. The total attenuation coefficient given by the algebraic sum of absorption and scattering components showed a reasonable agreement with the experimental data for overall frequencies. This study suggests that the scattering is the principal mechanism responsible for the variations of phase velocity and attenuation coefficient with frequency in water-saturated sandy sediments at high frequencies.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2007
    detail.hit.zdb_id: 1461063-2
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