نتایج جستجو برای: acoustic impedance volume
تعداد نتایج: 430710 فیلتر نتایج به سال:
A previous study [J. Acoust. Soc. Am. 111, 1102-1109 (2002)] showed that the occurrence of ultrasonically induced lung hemorrhage in rats was directly correlated to the level of lung inflation. In that study, it was hypothesized that the lung could be modeled as two components consisting of air and parenchyma (contiguous tissue [pleura and septa]). The speed of sound and lung impedance would th...
Identifying the scatterers and obtaining accurate estimates of ultrasonic scatterer sizes are beneficial adjuncts to characterize (diagnose) disease from ultrasonic backscatterer measurements. A new scatterer size estimation technique has been developed that is based on a 3D acoustic impedance map. Ultrasonic scatterer estimation techniques rely extensively on form factor functions to obtain es...
Density and Ultrasonic velocity Sucrose in 1M NaCl at 298.15K, 303.15K, 308.15K and 313.15K have been measured. Various ultrasonic and solution parameters such as adiabatic compressibility, change and relative change in adiabatic compressibility, acoustic impedance, available volume and free length have been calculated using these data. The present investigation has been used to exploit the pos...
The process by which sound is propagated in the head of a toothed whale is still a subject of discussion. Investigating the distribution of acoustic impedance calculated by density and Young's modulus is effective for quantitative comprehension because acoustic impedance determines the reflection coefficient of a sound wave. However, the sound propagation process of the toothed whale has been m...
Ultrasonic backscattered signals contain frequency-dependent information that is usually discarded to produce conventional B-mode images. It is hypothesized that parametrization of the quantitative ultrasound frequency-dependent information (i.e., estimating scatterer size and acoustic concentration) may be related to discrete scattering anatomic structures in tissues. Thus, an estimation techn...
Noise pollution has become one of the most serious problems of our society. Considerable part of unpleasant noise is transmitted into the interior of buildings through large vibrating planar structures windows with poor noise-isolation properties caused by their low flexural rigidity. In this Paper, we demonstrate and analyze a noise shielding using an active acoustic metamaterial (AAMM) with e...
The theory of acoustic wave scattering by many small bodies is developed for bodies with impedance boundary condition. It is shown that if one embeds many small particles in a bounded domain, filled with a known material, then one can create a new material with the properties very different from the properties of the original material. Moreover, these very different properties occur although th...
The density (ρ) and ultrasonic velocity (U) for ternary mixture of dimethyl acetamide, isobutyl methyl ketone and diethyl ether at different frequencies (2MHZ, 4MHz, 6MHZ, 8MHZ) have been measured at 308K. These data have been used to compute adiabatic compressibility (Ks), intermolecular free length (Lf), acoustic Impedance (Z), molar volume (Vm), molar sound velocity(R), molar compressibility...
The acoustic impedance at the diaphragm of an electroacoustic transducer can be modified using a range of active control strategies, amongst which is “direct impedance control”. This technique employs a combination of feedbacks, one on the acoustic pressure and the other on the diaphragm velocity, to the loudspeaker electric terminals, allowing significant modifications of the acoustic resonato...
In this work we present a new hybrid imaging technique that combines electrical impedance tomography (EIT) with acoustic tomography. The novel technique makes use of the fact that the absorbed electrical energy inside the body raises its temperature, thus leading to expansion effects. The expansion then induces an acoustic wave which can be recorded outside the body and consequently be used to ...
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