Ultrasonic Viscoelasticity and Excess Absorption in Polymer Solution
نویسندگان
چکیده
منابع مشابه
Ultrasonic measurements of breast viscoelasticity.
In vivo measurements of the viscoelastic properties of breast tissue are described. Ultrasonic echo frames were recorded from volunteers at 5 fps while applying a uniaxial compressive force (1-20 N) within a 1 s ramp time and holding the force constant for up to 200 s. A time series of strain images was formed from the echo data, spatially averaged viscous creep curves were computed, and viscoe...
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The dynamic shape relaxation of the two-layer vesicle is calculated. In addition to the undulation relaxation where the two bilayers move in the same direction, the squeezing mode appears when the gap between the two bilayers is small. At a large gap, the inner vesicle relaxes much faster, whereas the slow mode is mainly due to the outer-layer relaxation. We have calculated the viscoelasticity ...
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This paper constitutes a progress rersort on the develol•ment of an ultrasonic instrument for detecting microstructure. The principle of operation of the device (designated by the term "ultrasonic microscope") is as follows: The specimen is imbedded in a liquid, which closely matches it in acoustic impedance, and is irradiated with sho•t pulses of highdreqnency hound. Some of the ultrasonic ene...
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-The ultrasonic absorption was determined, by the transient thermoelectric method, for brain, heart, kidney, liver, tendon, and testis from cat, mouse, pig and beef. Comparison of these absorption {a) values with published values of attenuation (A) shows: (1) that the a and A coefficients have nearly the same frequency dependencies in the range 0.5-7 MHz, (2) that the magnitudes of a and A diff...
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RATIONALE AND OBJECTIVES Improvements in the diagnosis of early breast cancers depend on a physician's ability to obtain the information necessary to distinguish nonpalpable malignant and benign tumors. Viscoelastic features that describe mechanical properties of tissues may help to distinguish these types of lesions. MATERIALS AND METHODS Twenty-one patients with nonpalpable, pathology-confi...
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ژورنال
عنوان ژورنال: Polymer Journal
سال: 1989
ISSN: 0032-3896,1349-0540
DOI: 10.1295/polymj.21.905