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  • Comparative Studies. Non-European Languages/Literatures  (23)
  • 1
    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. 3485-3485
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3485-3485
    Abstract: To resolve the detection and orientation problem of autonomous underwater vehicle which platform is limited, single vector sensor with orientation ability is selected. The method of detection and bearing estimation based on vector sensor and its performance are researched in this paper. Vector sonar synthetical copy correlator and vector sonar synthetical adaptive correlator are put forward here, which use both pressure and velocity information. The composing principle and realizing method of the two processors above are studied and the processing gain, detecting probability and bearing estimation ability of the two are analyzed in acoustic multi-path condition. The theoretical results simulation and experiments show that all methods studied above have better performance than common copy correlation, and in multipath condition, the vector sonar synthetical adaptive correlation does better than vector sonar synthetical copy correlation in the aspect of processing gain and bearing estimation. Keywords: active detection; direction finding; autonomous underwater vehicle; vector sensor; synthetical copy correlator; synthetical adaptive correlator
    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
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  • 2
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2014
    In:  The Journal of the Acoustical Society of America Vol. 135, No. 4_Supplement ( 2014-04-01), p. 2380-2380
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 135, No. 4_Supplement ( 2014-04-01), p. 2380-2380
    Abstract: Different kinds of acoustic materials are used in a concert hall design, which has different functions such as diffusing, reflecting, or absorbing. The cushion of chairs in concert halls usually uses porous sound-absorbing material, whose absorbing attributes are mainly determined by its flow resistance. In the design of Concert Hall at Gulangyu Music School in Xiamen, we measured the flow resistance of materials, trying to acquire the best sound-absorbing attributes by adjusting the flow resistance, and also tested the material samples’ absorbing coefficients in reverberation room. In a nutshell, measuring and analyzing flow resistance is an advanced method in acoustic design, which could help acousticians decide the most suitable absorbing attributes of chairs, and acquire the best sound quality.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2014
    detail.hit.zdb_id: 1461063-2
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  • 3
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2014
    In:  The Journal of the Acoustical Society of America Vol. 135, No. 4_Supplement ( 2014-04-01), p. 2170-2170
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 135, No. 4_Supplement ( 2014-04-01), p. 2170-2170
    Abstract: The surface diffusivity is an important acoustical attribute of material, which is highly correlated with the sound quality of a concert hall. This paper introduces the theory and practical method to measure the surface diffusivity in laboratory, which is more precise and objective than traditional Surface Diffusivity Index (SDI), and then takes the design of the concert hall at Gulangyu Music School in Xiamen as an example, shows the diffusivity features of its six-sided-cylinder shaped GRG ceiling material, demonstrates the design method and significance of using diffusive material in room acoustic design.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2014
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  • 4
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 1996
    In:  The Journal of the Acoustical Society of America Vol. 100, No. 3 ( 1996-09-01), p. 1432-1446
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 100, No. 3 ( 1996-09-01), p. 1432-1446
    Abstract: The operator Riccati equation for the Dirichlet-to-Neumann map is derived from the exact operator factorization of the two-dimensional variable coefficient Helmholtz equation. Numerical schemes are developed for the operator Riccati equation and its variant using a local eigenfunction expansion. This leads to a practical computational method for acoustic wave propagation over large range distances, since the boundary value problem of the Helmholtz equation is reduced to ‘‘initial’’ value problems that are solved by marching in the range. The efficiency and accuracy of the method is demonstrated by numerical experiments including the plane-parallel range-dependent waveguide benchmark problem proposed by the Acoustical Society of America.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    RVK:
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 1996
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  • 5
    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. 3350-3350
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3350-3350
    Abstract: Minimum variance distortionless response (MVDR) algorithm has broken through the Rayleigh limit restrictions and makes higher resolutions possible. However, they are easily affected by complex underwater acoustic environments and are not sufficiently robust, so it is difficult to use them in real underwater systems. Time reversal mirror technology is a new method of localization, which may be effectively applied to target detection and localization. To improve its robustness, the MVDR algorithm is combined with time reversal mirroring for passive detection and location. This method makes full use of underwater multipath channel information and reduces the effects of complex underwater environments. The performance of time-reversal MVDR that is based on fixed diagonal loading and robust capon beamforming (RCB) was also studied. Simulations, water tank experiment and sea trial proved it is feasible and practical Keywords: MVDR; time reversal mirror; robust capon beamforming; passive location
    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
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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. 66, No. S1 ( 1979-11-01), p. S7-S7
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 66, No. S1 ( 1979-11-01), p. S7-S7
    Abstract: The magnitude of temperature structure coefficient is computed by sounder echo data. The results showed that the magnitude of CT2 has an obvious fluctuation with time. It has a character of positive bias distribution, and fits the logarithmic normal distribution. The analysis of the spectra CT2 showed that, the spectrum F(k) of CT2 usually fits the k−4 rule in stable and unstable stratifications. There exists a peak range of energy on the frequency range 10−1 − 3 × 10−4 s−1. The analysis of CT2 on time-height counter section indicates that the distribution of Cr CT2 has horizontal stratum structure in stable stratification and it fits the rule CT2 ∝ z−4/3 in unstable stratification. These results measured by acoustic radar agree with earlier direct observations by airplanes [L. R. Tsvang, Radio Sci. 4(12) (1962)].
    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) ; 2001
    In:  The Journal of the Acoustical Society of America Vol. 110, No. 5_Supplement ( 2001-11-01), p. 2619-2619
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 110, No. 5_Supplement ( 2001-11-01), p. 2619-2619
    Abstract: The parabolic equation method typically uses rational approximations to the square root operator. The split-step Padé method of Collins is more efficient and it uses rational approximations of the propagator—the exponential of the square root operator, say P=exp & lt;th & gt;is√1+X. Previously, only approximants of the type [p/p] are used. In order to damp the evanescent modes (and avoid instabilities), these [p/p] approximants are not the simple [p/p] Padé approximant of P. In this talk, we demonstrate that [p/(p+1)] Padé approximant of P can be used in the split-step Padé method. It is simple to construct and it has a good accuracy for approximating the propagating modes, yet it is guaranteed to suppress the evanescent modes. This approach will be compared with other variants of the split-step Padé method in numerical examples for acoustical waveguides.
    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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  • 8
    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. 3351-3351
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3351-3351
    Abstract: This paper explores the small-vocabulary speaker-independent isolated-word speech recognition technology. A recognition system based on a hybrid model of Hidden Markov Model and BP Neural Network is constructed. The HMM is used for computing the Viterbi output score which is inputted into the BP network to acquire the classification information. A corpus with more than 2500 speech samples is created, which includes three dialects (mandarin, shannxi dialect, English), and each kind of dialect contains four alarm word (“help”, “hijack”, “murder”, fire”). Recognition experiments are carried out using the corpus. The results show that the hybrid model has higher performance than the hidden Markov model.
    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
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  • 9
    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. 3366-3366
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 131, No. 4_Supplement ( 2012-04-01), p. 3366-3366
    Abstract: Multidrug resistance (MDR) in cancer cells is a significant obstacle to successful cancer therapy. Doxorubicin (DOX) is very active chemotherapeutic agent for the treatment of breast cancer and the efficacy of DOX is also restricted by multidrug resistance.Ultrasound (US) targeted destruction of drug loaded microbubbles (MBs) is gaining more and more attention as a promising strategy for locally drug delivery. In this article, through avidin–biotin binding of DOX-containing liposomes to the microbubbles, we developed DOX-liposome-containing microbubbles in order to investigate its effect of enhancing cellular uptake and cytotoxicity of DOX against drug-resistant cancer cells. The results demonstrated that treatment of cells with ultrasound and DOX-liposome-containing microbubbles caused a significant higher drug uptake in DOX-resistant MCF-7 cells, compared with control (DOX-liposome). More importantly, a significant enhancement of tumor growth inhibition against DOX-resistant MCF-7 cells was found when using the drug-liposome-containing microbubbles combined with ultrasound.Compared with DOX-liposome treatment, the cytotoxicity effect was greatly enhanced from 21% to 60%. By further mechanism study, DOX-loaded microbubbles plus ultrasound induced significant apoptosis in MDR line of MCF-7 cells.
    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
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  • 10
    Online Resource
    Online Resource
    Acoustical Society of America (ASA) ; 2020
    In:  The Journal of the Acoustical Society of America Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2560-2560
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 148, No. 4_Supplement ( 2020-10-01), p. 2560-2560
    Abstract: Cavitation is widely existing in focused ultrasound (FUS)-mediated therapies in the brain, such as FUS in combination with microbubble-induced blood-brain barrier disruption, nonthermal ablation, as well as transcranial histotripsy therapy. Accurately knowing the 3-D location of cavitation in real time can improve the treatment targeting accuracy and avoid off-target tissue damage. However, the skull induces strong phase and amplitude aberration to the cavitation signals and presents a significant challenge to the transcranial cavitation localization. Existing techniques for 3-D cavitation localization use hemispherical multi-element arrays combined with passive beamforming and adaptive skull-specific correction algorithm. However, these techniques require expensive equipment and treatment planning. Their time-consuming computations limit applications in real-time cavitation monitoring, which is critically needed to ensure the safety and efficacy of the FUS treatment. The object of this study was to investigate the feasibility of using a four-sensor network to transcranially locate the cavitation source in 3-D by time difference of arrival algorithm. The positional error of transcranial cavitation localization with the human skull along x, y, and z axes were 1.7 ± 1.2 mm, 1.6 ± 1.7 mm, and 4.1 ± 1.5 mm, respectively. For comparison, the positional error of without the human skull were 1.2 ± 1.8 mm, 0.9 ± 1.6 mm, and 3.1 ± 2.3 mm, respectively.
    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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