نتایج جستجو برای: acoustic barriers

تعداد نتایج: 166440  

The acoustic wave velocity depends on elasticity and density at most materials, but because of anisotropy and especially piezoelectric coupling effect, the acoustic wave propagation at piezoelectric based crystalloacoustic materials, is an applied and challenging problem. In this paper, using modified Christoffel's equation based on group velocity concept, the effect of anisotropy and piezoelec...

Journal: :acta medica iranica 0
m. pourissa s. refahi m. javid majd a. mardi

biophysical profile (bpp) test is the most commonly used antenatal test of fetal well-being. purpose of this study is determining the influence of acoustic stimulation (as) on bpp testing time. about 55 pregnant women at 35 to 42 weeks who referred to department of obstetric & gynecology at university of medical sciences, tabriz, iran, were selected randomly. we used abdominal ultrasound guidan...

Journal: :Evolution; international journal of organic evolution 2007
Sean P Mullen Tamra C Mendelson Coby Schal Kerry L Shaw

Understanding the origin and maintenance of barriers to gene exchange is a central goal of speciation research. Hawaiian swordtail crickets (genus Laupala) represent one of the most rapidly speciating animal groups yet identified. Extensive acoustic diversity, strong premating isolation, and female preference for conspecific acoustic signals in laboratory phonotaxis trials have strongly support...

Journal: :iranian journal of cancer prevention 0
a agrawal s.j vagh s.n gosavi b pachpande g ubeja

abstract   a cystic acoustic neurinoma almost entirely consists of a cystic component and is a well recognized subtype of acoustic schwannoma. we report a case of a 40-year- old male patient who presented with clinical features of a left cerebello-pontine angle mass lesion and ct scan findings mimicking the diagnosis of an epidermoid cyst. however intraoperative and histopathological findings w...

2017
Helmut G. Kratochvil Michael Pollirer

Measurements of photosynthetic processes in hydrophytes mostly involve photosynthometers, which capture the escaping gas for subsequent analysis The most common method to detect changes in the rate of photosynthetic processes is to count the series of escaping gas bubbles. The emerging bubbles are either simply counted or they are recorded using light barriers, which is very difficult because o...

2006
M. G. Shats H. Xia H. Punzmann

The ubiquity of zonal flows in toroidal plasma is now well recognized (see [1] for review on zonal flow theory and a special March issue of Plasma Physics and Controlled Nuclear Fusion 87 (2006) for the latest experimental papers). Two main branches of zonal flows have been identified. Both have zero poloidal and toroidal mode numbers, m = n = 0. One of them is a zero-frequency, finitebandwidth...

2013
S N Chandler-Wilde

Acoustic wave scattering problems arise in application areas as diverse as the modelling of sonar, acoustic noise barriers, and ultrasound. In many practical applications the characteristic length scale L of the domain is large compared to the wavelength  . In such cases the small dimensionless wavelength L /  leads to oscillatory solutions. In order to resolve these solutions, standard numer...

2014
Nicolas COTE Jérôme VASSEUR Quentin SOURON Anne-Christine HLADKY-HENNION

Several noise barriers made of phononic crystals (i.e. manmade composite materials with a periodic structure) have been designed over the last decade. The periodic structure of phononic crystal avoids sound propagation in a defined frequency range called Bragg band gap (i.e. waves are evanescent). This study aims at quantifying the perceptual impact of a noise barrier based on a phononic crysta...

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