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  • Comparative Studies. Non-European Languages/Literatures  (8)
  • 1
    Online Resource
    Online Resource
    Dosimetry measurement of HIFU field using a fiber-optical probe hydrophone
    Acoustical Society of America (ASA) ; 2004
    In:  The Journal of the Acoustical Society of America Vol. 115, No. 5_Supplement ( 2004-05-01), p. 2491-2491
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 115, No. 5_Supplement ( 2004-05-01), p. 2491-2491
    Abstract: Characterization of the acoustic field of high-intensity focused ultrasound (HIFU) transducers by conventional PVDF membrane and needle hydrophones is problematic due to limited bandwidth, spatial averaging, and damage to the hydrophone. Here, we report the use of a self-calibrated fiber-optical probe hydrophone (FOPH-500) for HIFU dosimetry measure- ment. The hydrophone (0.1-mm sensing element) was scanned in the focal volume of a 1.1-MHz HIFU transducer (F=63 mm, f number=0.9) at 0.2-mm steps using a computer-controlled 3D positioning system. When the input voltage Vp−p applied to the transducer was increased from 28 to 225 volts, the peak compressive and tensile pressure values at the transducer focus were found to be P+=1.7–18.9 MPa and P−=−1.33–−8.14 MPa, respectively. The corresponding spatial peak intensities were calculated to be ISP=69–3968 W/cm2. Nonlinear propagation with harmonics generation was dominant at high intensity levels, leading to a reduced −6-dB beamwidth of the compressive wave from 1.8 to 1.3 mm and an increased −6-dB beamwidth of the tensile wave from 1.6 to 1.8 mm. Overall, FOPH-500 was found to be a reliable tool for characterizing the acoustic field of HIFU transducers.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4782861
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2004
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Understanding the relationship between acoustics and articulation of nasal and oral vowels
    Acoustical Society of America (ASA) ; 2016
    In:  Journal of the Acoustical Society of America Vol. 140, No. 4_Supplement ( 2016-10-01), p. 3219-3219
    Details
    In: Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 140, No. 4_Supplement ( 2016-10-01), p. 3219-3219
    Abstract: While real-time magnetic resonance imaging (rt-MRI) provides high spatiotemporal resolution for speech research, the associated audio is noisy, presenting a challenge for research on the relationship between articulation and the acoustic signal and solving the articulatory inversion problem. Using state-of-the-art denoising methods, the current study denoised rt-MRI audio associated with nasal and oral French vowels produced by one speaker, and extracted F1-3 from the midpoints of each vowel for /a, o, e/ and their nasal counterparts. Oblique images were taken of the velopharyngeal port at 25 frames/second, and average pixel intensity (API) in the velopharyngeal region was taken from images corresponding to the vowel midpoint. General additive models showed a significant relationship between API and F1 for oral and nasal vowels. (Lower API indicates a wider velopharyngeal opening.) F1 of /ã/ was lower than /a/, while F1 was higher in the nasal /õ/ and /ẽ/ than their oral counterparts, all of which are expected effects of naso-pharyngeal coupling. These results show that the acoustic recordings produced during rt-MR imaging can be used to explore the relationship between articulation and acoustics, and can give insight into the articulatory effects of nasality, something difficult to understand through acoustics alone.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4970150
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2016
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Using partially separable functions to image spatiotemporal aspects of Arabic pharyngealization
    Acoustical Society of America (ASA) ; 2012
    In:  The Journal of the Acoustical Society of America Vol. 132, No. 3_Supplement ( 2012-09-01), p. 2091-2091
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 132, No. 3_Supplement ( 2012-09-01), p. 2091-2091
    Abstract: It has been challenging to estimate the temporal domain of pharyngealization in Arabic. Conventional MRI has limited assessment of dynamic pharyngeal shape during speech. In this study, fast spiral sequences, combined with partially separable functions, were used to achieve a relatively high spatiotemporal resolution (2.2 mm × 2.2 mm × 8.0 mm, at a frame rate of 86 fps) during dynamic speech imaging of a single midsagittal slice. One male speaker of Levantine Arabic produced pairs of words that differed minimally by one speech sound: pharyngeal fricative /ħ/ or non-pharnyngeal /b/. Each word was produced 23 times. The temporal extent of pharyngeal tissue displacement associated with /ħ/ was investigated. Sounds were segmented with reference to a simultaneous, noise-canceled acoustic recording. Spatiotemporal maps of differential pixel intensity (interpreted as tissue displacement) were generated for each segment preceding the pharyngeal / non-pharyngeal test segment. Average differential pixel intensity in the pharyngeal area was then sampled during these preceding segments. T-tests revealed significant differences (p  & lt; 0.01) up to two segments away from the pharyngeal / non-pharyngeal test segment. This technique should permit investigation of spatiotemporal aspects of pharyngealization across different varieties of Arabic, where distance and direction of pharyngealization are said to vary systematically.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.4755732
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2012
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Variations of stress field and stone fracture produced at different lateral locations in a shockwave lithotripter field
    Acoustical Society of America (ASA) ; 2021
    In:  The Journal of the Acoustical Society of America Vol. 150, No. 2 ( 2021-08-01), p. 1013-1029
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 150, No. 2 ( 2021-08-01), p. 1013-1029
    Abstract: During clinical procedures, the lithotripter shock wave (LSW) that is incident on the stone and resultant stress field is often asymmetric due to the respiratory motion of the patient. The variations of the LSW-stone interaction and associated fracture pattern were investigated by photoelastic imaging, phantom experiments, and three-dimensional fluid-solid interaction modeling at different lateral locations in a lithotripter field. In contrast to a T-shaped fracture pattern often observed in the posterior region of the disk-shaped stone under symmetric loading, the fracture pattern gradually transitioned to a tilted L-shape under asymmetric loading conditions. Moreover, the model simulations revealed the generation of surface acoustic waves (SAWs), i.e., a leaky Rayleigh wave on the anterior boundary and Scholte wave on the posterior boundary of the stone. The propagation of SAWs on the stone boundary is accompanied by a progressive transition of the LSW reflection pattern from regular to von Neumann and to weak von Neumann reflection near the glancing incidence and, concomitantly, the development and growth of a Mach stem, swirling around the stone boundary. The maximum tensile stress and stress integral were produced by SAWs on the stone boundary under asymmetric loading conditions, which drove the initiation and extension of surface cracks into the bulk of the stone that is confirmed by micro–computed tomography analysis.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/10.0005823
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2021
    detail.hit.zdb_id: 1461063-2
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  • 5
    Online Resource
    Online Resource
    Measurement of high intensity focused ultrasound fields by a fiber optic probe hydrophone
    Acoustical Society of America (ASA) ; 2006
    In:  The Journal of the Acoustical Society of America Vol. 120, No. 2 ( 2006-08-01), p. 676-685
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 120, No. 2 ( 2006-08-01), p. 676-685
    Abstract: The acoustic fields of a high intensity focused ultrasound (HIFU) transducer operating either at its fundamental (1.1MHz) or third harmonic (3.3MHz) frequency were measured by a fiber optic probe hydrophone (FOPH). At 1.1MHz when the electric power applied to the transducer was increased from 1.6to125W, the peak positive∕negative pressures at the focus were measured to be p+=1.7–23.3MPa and p−=−1.2–−10.0MPa. The corresponding spatial-peak pulse-average (ISPPA) and spatial-average pulse-average (ISAPA) intensities were ISPPA=77–6000W∕cm2 and ISAPA=35–4365W∕cm2. Nonlinear propagation with harmonics generation was dominant at high intensities, leading to a reduced −6dB beam size (L×W) of the compressional wave (11.5×1.8–8.8×1.04mm) but an increased beam size of the rarefactional wave (12.5×1.6–13.2×2.0mm). Enhancement ratio of absorbed power density in water increased from 1.0 to 3.0. In comparison, the HIFU transducer working at 3.3MHz produced higher peak pressures (p+=3.0–35.1MPa and p−=−2.5–−13.8MPa) with smaller beam size (0.5×4mm). Overall, FOPH was found to be a convenient and reliable tool for HIFU exposimetry measurement.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.2214131
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2006
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Articulatory correlates of phonemic and coarticulatory nasalization
    Acoustical Society of America (ASA) ; 2017
    In:  The Journal of the Acoustical Society of America Vol. 142, No. 4_Supplement ( 2017-10-01), p. 2552-2552
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 142, No. 4_Supplement ( 2017-10-01), p. 2552-2552
    Abstract: Phonological theory distinguishes nasal and oral vowel counterparts by velopharyngeal port opening, neglecting other phonetic differences between phonemic and coarticulatory nasalization. Recent articulatory work provides evidence of oropharyngeal distinctions, in addition to velic lowering. This study (12 Brazilian Portuguese speakers) uses real-time MRI to investigate oropharyngeal differences between oral, phonemically nasal, and phonetically nasalized vowels /a, i, u/. Tissue boundaries in midsagittal vocal tract images were automatically detected to reveal each vowel repetition’s aperture function. Principal Components Analysis determined vocal tract regions responsible for the greatest variance in the data. Time-dynamic analyses of vocal tract area in these regions used smoothing spline ANOVA. Results show the tongue body and/or hyperpharynx as the most important articulators. For /a/, nasal vowels demonstrate wider hyperpharyngeal and narrower tongue body regions compared to oral vowels. For /u/, oral vowels show wider hyperpharyngeal and narrower tongue body regions. For /i/, nasal vowels demonstrate wider tongue body and narrower hyperpharyngeal regions. Nasalized vowels manifest apertures intermediate between oral and nasal vowels for /a/ and /u/, and similar to oral vowels for /i/. Results are largely in line with expected acoustic effects of nasalization, and demonstrate that phonetic differences exist between phonemic and coarticulatory nasalization.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5014329
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2017
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    A real-time MRI investigation of the role of lingual and pharyngeal articulation in the production of the nasal vowel system of French
    Elsevier BV ; 2015
    In:  Journal of Phonetics Vol. 50 ( 2015-05), p. 34-51
    Details
    In: Journal of Phonetics, Elsevier BV, Vol. 50 ( 2015-05), p. 34-51
    Type of Medium: Online Resource
    ISSN: 0095-4470
    URL: Article
    DOI: 10.1016/j.wocn.2015.01.001
    RVK:
    EQ 1000
    RVK:
    EQ 2688
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2015
    detail.hit.zdb_id: 1469783-X
    SSG: 7,11
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  • 8
    Online Resource
    Online Resource
    Spontaneous nasalization after glottal consonants in Thai: An rt-MRI investigation of rhinoglottophilia
    Acoustical Society of America (ASA) ; 2017
    In:  The Journal of the Acoustical Society of America Vol. 142, No. 4_Supplement ( 2017-10-01), p. 2552-2552
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 142, No. 4_Supplement ( 2017-10-01), p. 2552-2552
    Abstract: The affinity between glottal and nasal articulations (“rhinoglottophilia”) facilitates spontaneous nasalization. In Thai, low vowels nasalize after /h/ and to a lesser degree after glottal stop. Nasalization after /h/ may occur because breathiness and nasalization share high energy at low frequencies and a raised first harmonic. Glottal consonants generally may cause nasalization because aerodynamically they do not require a closed velopharyngeal port. We investigated whether Thai vowels after /h/ and glottal stop exhibit similar degrees of velopharyngeal opening (VPO) and compared these results with acoustic measures of nasalization / breathiness. We calculated nasalization / breathiness by the energy ratio of low and high harmonics; we measured VPO by processing oblique real-time magnetic resonance images of the velopharyngeal port. Four Thai speakers (two females, two males) produced relatively large VPO and high acoustic nasalization / breathiness after /h/. Female speakers nasalized vowels after glottal stop, though they produced overall less VPO and lower acoustic nasalization / breathiness when compared to vowels after /h/. In Thai, vowels after /h/ exhibit more physiological nasalization than vowels after glottal stop; furthermore, low VPO is associated with low acoustic nasalization / breathiness. We conclude VPO is primarily responsible for impressions of nasalization in this context.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.5014330
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2017
    detail.hit.zdb_id: 1461063-2
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