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  • 1
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2018
    In:  The Journal of the Acoustical Society of America Vol. 144, No. 6 ( 2018-12-01), p. 3563-3574
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 144, No. 6 ( 2018-12-01), p. 3563-3574
    Abstract: A method is developed for compensating absolute pressure measurements made by a calibrated passive cavitation detector (PCD) to estimate the average acoustic power radiated from a region of interest (ROI) defined to encompass all cavitating bubbles. A diffraction correction factor for conversion of PCD-measured pressures to cavitation-radiated acoustic power per unit area or volume is derived as a simple analytic expression, accounting for position- and frequency-dependent PCD sensitivity. This approach can be applied to measurements made by any PCD without precise knowledge of the number, spatial, or temporal distribution of cavitating bubbles. The diffraction correction factor is validated in simulation for a wide range of ROI dimensions and frequencies. The correction factor is also applied to emission measurements obtained during in vitro ultrasound-enhanced sonophoresis experiments, allowing comparison of stable cavitation levels between therapeutic configurations with different source center frequencies. Results incorporating sonication at both 0.41 and 2.0 MHz indicate that increases in skin permeability correlate strongly with the acoustic power of subharmonic emissions radiated per unit skin area.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2018
    detail.hit.zdb_id: 1461063-2
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  • 2
    Online Resource
    Online Resource
    Springer Science and Business Media LLC ; 1974
    In:  Computers and the Humanities Vol. 8, No. 3 ( 1974-5), p. 183-190
    In: Computers and the Humanities, Springer Science and Business Media LLC, Vol. 8, No. 3 ( 1974-5), p. 183-190
    Type of Medium: Online Resource
    ISSN: 0010-4817 , 1572-8412
    RVK:
    RVK:
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 1974
    detail.hit.zdb_id: 2195235-8
    detail.hit.zdb_id: 215905-3
    detail.hit.zdb_id: 1475520-8
    SSG: 24
    SSG: 5,1
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1954
    In:  The Journal of the Acoustical Society of America Vol. 26, No. 5_Supplement ( 1954-09-01), p. 950-951
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 26, No. 5_Supplement ( 1954-09-01), p. 950-951
    Abstract: The ultrasonic resonator interferometer has been used to measure the ultrasonic velocity at 30°C in ethylidene chloride (1,1 dichioroethane CH3CHCl2), and ethylene chloride (1,2 dichlorocthane CH2Cl CH2Cl) vapors, as a function of frequency over pressure. The ranges of f/p employed are 0.9 to 104 Mc sec−1 atmos−1 in the case of the former vapor, and 1.0 to 100 in the latter. There is an indication of double relaxation in both the cases, the principal frequency/pressure ratios being in the neighborhood of 58 ± 5 in ethylidene chloride and 98 ± 5 in ethylene chloride, which are estimated by a superposition of the experimental curves (velocity vs f/p) with the theoretical curves obtained by using the spectroscopic data along with Kneser's formula. There is good agreement between the experimental and theoretical curves, thereby showing that the observed dispersion in ultrasonic velocity is due to the slow rate of energy exchange between translational and vibrational states.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1954
    detail.hit.zdb_id: 1461063-2
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1974
    In:  The Journal of the Acoustical Society of America Vol. 55, No. 2_Supplement ( 1974-02-01), p. 426-426
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 55, No. 2_Supplement ( 1974-02-01), p. 426-426
    Abstract: Rotor blade loading fluctuations have been recognized to be the dominant source of noise in subsonic fan rotors. Since the blade section drag force is of a lower order of magnitude than the lift force, the farfield sound is examined in terms of dipole radiation from the lift fluctuations on the rotor blades. These dipole sources can be classified into two catagories: (a) ordered sources arising from the effect of the deterministic component of the inflow distortion, and (b) random sources due to turbulence in the inflow. Theoretical analyses of both types of dipole radiation are presented. It is shown that even a small magnitude of steady-state inflow distortion can generate high levels of tone noise at blade passing frequency harmonics. For sufficiently large length scale of turbulence, the random lift force on the blades also gives rise to such discrete tone levels. [This work was supported by NASA Ames Research Center under Contract No. NAS2-6401.]
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1974
    detail.hit.zdb_id: 1461063-2
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  • 5
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2001
    In:  The Journal of the Acoustical Society of America Vol. 109, No. 5_Supplement ( 2001-05-01), p. 2457-2457
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 109, No. 5_Supplement ( 2001-05-01), p. 2457-2457
    Abstract: A laparoscopic ultrasound probe was developed for image-guided high-intensity focused ultrasound (HIFU) ablation of renal tissue. The probe expands the application of a commercially available HIFU system (SonablateTM) to laparascopic operations. It consists of a 4-MHz focused rectangular HIFU piezoceramic transducer (30×10 mm, FL=30 mm) confocally coupled with a circular central element (8 mm in diameter) used for real-time pulse-echo imaging during treatment. Precise mechanical movements of the transducer enable it to treat targeted tissue volumes. The probe was fully characterized by measuring its electrical impedance, acoustic field, and total acoustic power output. Moreover, the acoustic field was simulated using an analytical model. The laparoscopic probe was able to generate acoustic power levels up to 35 W that correspond to focal intensities over 2200 W/cm2 in tissue, sufficient for tissue ablation through rapid temperature rise ( & gt;90 & lt;th & gt;°C) and cavitation mechanisms. The probe was tested in an in vivo animal study in which 15 pigs were treated through a sterile laparoscopic procedure. A lesion with dimensions of 23×17×11 mm ±1 mm was successfully generated in the left kidney of each pig during a treatment time of less than 30 min. Histology results demonstrated homogeneous well-delineated lesions generated in the target region.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2001
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1979
    In:  The Journal of the Acoustical Society of America Vol. 65, No. 1 ( 1979-01-01), p. 223-228
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 65, No. 1 ( 1979-01-01), p. 223-228
    Abstract: Unlike most frequency domain methods for pitch extraction, here the pitch is computed from a few selected high quality peaks in the spectrum, achieving greater reliability. A new approximate greatest common devisor (AGCD) algorithm is proposed to compute the fundamental frequency of a given set of corrupted harmonics. Authentic harmonic peaks ar4e obtained by logical filtering of the spectrum and the computed fundamental frequency is subjected to an error test using the best of the harmonic peaks. Thus the algorithm provides a voiced–unvoiced decision, as well as the pitch for voiced regions. The results are uniformly good for male and female voices, and error rates are comparable to those for the best algorithms reported in the literature.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1979
    detail.hit.zdb_id: 1461063-2
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  • 7
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1982
    In:  The Journal of the Acoustical Society of America Vol. 72, No. S1 ( 1982-11-01), p. S78-S78
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 72, No. S1 ( 1982-11-01), p. S78-S78
    Abstract: There are a number of LPC-based speech synthesis integrated circuits available on the market today. For many practical applications of these chips, it is advantageous to utilize a real-time code generation system. Traditional LPC analysis techniques, such as covariance, autocorrelation, and PARCOR, process blocks of speech samples yielding one set of LPC parameters for each block. Autocorrelation and covariance techniques require matrix inversion and are too complex for hardware implementation. PARCOR-type lattice techniques require a large amount of data storage at each stage of the lattice. In this study we have evaluated a fast and efficient LPC analysis technique suitable for hardware implementation for real-time operation. Unlike the traditional LPC analysis techniques, the real-time technique processes individual samples of speech. The LPC parameters are first initialized and then updated as each sample is processed. Computer simulation has shown that the real-time technique yields reasonable spectra. Computer generated synthetic sounds from the real-time technique have almost the same quality as those generated from the block-data techniques. Sounds synthesized using the real-time technique on our SP0256 chip are indistinguishable from those synthesized using traditional techniques.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1982
    detail.hit.zdb_id: 1461063-2
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  • 8
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2023
    In:  The Journal of the Acoustical Society of America Vol. 153, No. 3_supplement ( 2023-03-01), p. A350-A350
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 153, No. 3_supplement ( 2023-03-01), p. A350-A350
    Abstract: Monitoring of radiofrequency ablation (RFA) is desirable to improve safety and efficacy of liver tumor treatment. Three-dimensional ultrasound echo decorrelation imaging can successfully predict local ablation effects but has had limited success in mapping ablation zone margins and local tissue temperature. Here, a supervised deep learning approach is investigated to improve prediction of ablation zones and tissue temperature from 3D echo decorrelation images. RFA was performed on ex vivo human liver tissue, including normal, fibrotic, and cirrhotic liver (N  & gt; 30). During ablation, pairs of echo volumes were acquired with a 4.5 MHz transesophageal matrix array, 3D echo decorrelation images were computed for each volume pair, and temperatures measured by fourthermocouples integrated into the RFA probe were recorded. Tissue was then frozen, sectioned, scanned, and ablation zones were manually segmented. For prediction of ablation zones, B-mode and echo decorrelation images were input to a U-net convolutional neural network to segment ablation margins, with histology serving as ground truth for training and cross-validation. For prediction of temperature, echo decorrelation values at the thermocouple locations were used as input to train a dense network, minimizing mean-squared-error versus measured temperatures. The results indicate promise for improved mapping of tissue ablation and temperature.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2023
    detail.hit.zdb_id: 1461063-2
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  • 9
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1955
    In:  The Journal of the Acoustical Society of America Vol. 27, No. 2 ( 1955-03-01), p. 321-325
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 27, No. 2 ( 1955-03-01), p. 321-325
    Abstract: The ultrasonic resonator interferometer has been used to measure the ultrasonic velocity at 30°C in 1,1-dichloroethane (ethylidene chloride, CH3CHCl2) and 1,2-dichloroethane (ethylene chloride,CH2Cl-CH2Cl) vapors as a function of frequency over pressure. The ranges f/p employed are 0.8 to 100 Mc sec−1 atmos−1 in the case of ethylidene chloride and 1.0 to 100 Mc sec−1 atmos−1 in the case of ethylene chloride. The velocities have been corrected for nonideality of the two vapors. Dispersion of ultrasonic velocity occurs in both the cases and this is ascribed to the slow rate of energy exchange between translational and vibrational states. There is evidence of double relaxation in the two cases, the principal f/p ratios at 30°C being 76.5 Mc sec−1 atmos−1 for the former and 102 Mc sec−1 atmos−1 for the latter.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1955
    detail.hit.zdb_id: 1461063-2
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  • 10
    Online Resource
    Online Resource
    JSTOR ; 1969
    In:  Journal of the American Oriental Society Vol. 89, No. 4 ( 1969-10), p. 816-
    In: Journal of the American Oriental Society, JSTOR, Vol. 89, No. 4 ( 1969-10), p. 816-
    Type of Medium: Online Resource
    ISSN: 0003-0279
    RVK:
    RVK:
    Language: Unknown
    Publisher: JSTOR
    Publication Date: 1969
    detail.hit.zdb_id: 2065887-4
    SSG: 6,24
    SSG: 1
    SSG: 6,23
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