نتایج جستجو برای: acoustic dispersion

تعداد نتایج: 146662  

حکیمی‌پژوه, حسین, روحانی, محمودرضا, کارگریان, آمنه,

In this paper with use of Particle in Cell (PIC) simulation method in one dimension the dynamic of ion acoustic soliton is studied. in this method the ions are monitored as particles and the electrons are assumed to be in thermal equilibrium. The dispersion relation of ion acoustic waves is investigated. The results are in good agreement with analytical results showing that in linear regime our...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشکده علوم پایه 1389

چکیده ندارد.

عبداله, امیر, ملکی, مسعود,

Propagation and dispersion of acoustic waves is one of the important phenomena in physics. Acoustic-waves are nowadays widely used in a variety of applications ranging from underwater communications, identification and specification of the internal defects of materials to extracorporeal shock wave lithotripsy. Apart from application and utilization of such phenomena, study on production and pro...

In this research, the dispersion properties of magneto-acoustic waves in a plasma in the presence of quantum effects are studied. For this purpose, we employ a system of quantum fluid equations and Maxwell equations to derive a generalized dispersion relation. Our analytical results show that the wave frequency is modified by quantum corrections. Also, numerical estimations reveal that the effe...

Journal: :Journal of physics. Condensed matter : an Institute of Physics journal 2012
Taras Bryk J-F Wax

The spectra of longitudinal and transverse collective excitations in liquid binary metallic Na(c)K(1-c) alloys are studied for pure components and four different concentrations. A theoretical generalized collective modes approach is used to analyze the concentration dependence of the dispersion of acoustic and optic branches in a wide region of wavenumbers. The dispersion of longitudinal collec...

Journal: :پژوهش های زبانی 0
وحید صادقی استادیار دانشگاه بین المللی امام خمینی (ره) نیلوفر منصوری هره دشت استادیار دانشگاه پیام نور

this paper addresses the validity of two hypotheses concerning changes of vowel quality in persian. the theory of centralization claims that there is a strong correlation between vowel duration and vowel quality. as vowel duration is shortened in unstressed contexts, the size of the vowel inventory reduces toward the center, leading to considerable overlap between different categories and a red...

2009
Guillaume A. Brès Franck Pérot David Freed

Numerical simulations are performed to investigate the fundamental acoustics properties of the Lattice–Boltzmann method. The propagation of planar acoustic waves is studied to determine the resolution dependence of numerical dissipation and dispersion. The two setups considered correspond to the temporal decay of a standing plane wave in a periodic domain, and the spatial decay of a propagating...

2016
Louis F.M. ten Bosch

The 'vowel dispersion theory' states that the acoustic structure of the vowel inventory in a language can be explained by optimizing the acoustic inter-vowel contrast, under the constraint of articulatory conditions. In this paper, the primacy of the acoustic principles of contrast and effort is questioned by considering the possible effect of the lexicon on vowel dispersion. As an extreme poin...

2016
T. Chartier E. Jorge P. Boch

Ultrasonic agitation is a very efficient method for deagglomeration and dispersion of ceramic slurries (alumina and barium titanate). The influence of parameters such as acoustic power, temperature, and treatment duration on the dispersion efficiency has been studied. For

1996
René Carré

A deductive approach is developed to predict vocalic systems. First, vowels are proposed from an efficient and simple use of an acoustic tube. Then, a maximum acoustic dispersion criterion is applied to classify the obtained vowels.

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