نتایج جستجو برای: acoustic impedance

تعداد نتایج: 120231  

Stochastic seismic inversion is a family of inversion algorithms in which the inverse solution was carried out using geostatistical simulation. In this work, a new 3D stochastic seismic inversion was developed in the MATLAB programming software. The proposed inversion algorithm is an iterative procedure that uses the principle of cross-over genetic algorithms as the global optimization techniqu...

2008
Marguerite Brown

To better understand the unique tone of both a plastic and wooden clarinet, an analysis of sound production was taken by several methods. The sound output from the clarinet was recorded and run through a phase-sensitive wave analysis program to determine the phase relations, frequencies, and intensities of the most prominent harmonics. Using a piezoelectric transducer, phase-sensitive measureme...

Journal: :The Journal of the Acoustical Society of America 2015

2007
Gabriel Pablo Nava Yoichi Sato Shinichi Sakamoto Yosuke Yasuda

In situ measurement of acoustic impedance is traditionally performed using pairs of microphones located close to the test surface. However, this method becomes troublesome if inaccessible complex-shaped surfaces, such as those in a real room, are considered. To overcome this problem a method to estimate the normal acoustic impedance on the interior surfaces of a room is proposed. As input data,...

Journal: :The Journal of clinical investigation 1985
S A Wickline L J Thomas J G Miller B E Sobel J E Perez

We have shown previously that the physiologic, mechanical cardiac cycle is associated with a parallel, cardiac cycle-dependent variation of integrated backscatter (IB). However, the mechanisms responsible are not known. The mathematical and physiological considerations explored in the present study suggest that the relationship between backscatter and myocardial contractile function reflects cy...

Journal: :Physics in medicine and biology 2011
Kazumichi Kobayashi Tetsuya Kodama Hiroyuki Takahira

In the case of extracorporeal shock wave lithotripsy (ESWL), a shock wave-bubble interaction inevitably occurs near the focusing point of stones, resulting in stone fragmentation and subsequent tissue damage. Because shock wave-bubble interactions are high-speed phenomena occurring in tissue consisting of various media with different acoustic impedance values, numerical analysis is an effective...

2015
Jont B. Allen Judi Lapsley Miller Patricia S. Jeng Harry Levitt

Measurements of middle ear (ME) acoustic power flow and related measures (e.g., reflectance, absorbance, impedance, resistance, and reactance) have several important advantages over other measures of acoustic impedance, such as the clinical “gold standard” measure, tympanometry. In addition to its wide bandwidth and ease of use, the absorbance curve, on a dB scale, has a shape that is similar t...

2016
You-Lin Tu Shih-Jui Chen Yean-Ren Hwang

In this paper, acoustic tweezers which use beam forming performed by a Fresnel zone plate are proposed. The performance has been demonstrated by finite element analysis, including the acoustic intensity, acoustic pressure, acoustic potential energy, gradient force, and particle distribution. The acoustic tweezers use an ultrasound beam produced by a lead zirconate titanate (PZT) transducer oper...

2014
Md AYUB Anthony C. ZANDER Carl Q. HOWARD Benjamin S. CAZZOLATO Vesselin N. SHANOV Noe T. ALVAREZ David M. HUANG

Advances in nanotechnology have provided acoustic researchers with a number of new materials with nano-fibres and nano-pores that can potentially be implemented as an acoustic porous absorber. This paper investigates the acoustic absorption behaviour of carbon nanotube (CNT) arrays, in order to quantify the acoustic characteristics and absorption performance of nanoscopic fibres in comparison w...

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