نتایج جستجو برای: Baryonic Acoustic Waves
تعداد نتایج: 194964 فیلتر نتایج به سال:
in the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. for this purpose, we used both wmap9 and planck data to study how the radius changes with redshift in these mod-els. we used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. the mechanism of structure formation f...
In the current paper, we have studied the effect of dark energy on for-mation where dark energy exists in the background. For this purpose, we used both WMAP9 and Planck data to study how the radius changes with redshift in these mod-els. We used different data sets to fix the cosmological parameters to obtain a solution for a spherical region under collapse. The mechanism of structure formation f...
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...
Investigating waves propagation’s equation in the atmosphere is one of the important and widely used issues in various sciences, which has attracted many researchers. A type of propagating waves is an acoustic-gravity wave. These type of waves have a lot of stationarity properties and can be propagate to a high altitude in the atmosphere. The equation of acoustic-gravity wave propagation is a h...
Propagation of dust ion acoustic waves in plasmas composed of nonthermal distributed electrons and stationary dust particles is investigated. Nonlinear Schrdinger equation is derived to describe small amplitude waves, using the reduction perturbation technique. Modulation instability of dust ion acoustic waves is analysed for this system. Parametric investigation indicates that growth rate of...
the use of acoustic waves in researches related to sea water is of most importance among scientistsrecently. since these waves are the only waves, transmitted in water with lowest attenuation and high speed, they canbe used in many scientific fields. the main goal of this research is to better understand the physics and mechanismsof sound-seabed interaction, including acoustic penetration, prop...
Slow magneto-acoustic waves are often observed in polar plumes and active region fan loops. The observed periodicities of these waves are in the range of 1- 40 minutes. Mainly, the ratio of damping time to the oscillation period is less than 2 (equal to the ratio damping length to the wave length), which corresponds to the strong damping regime. In general, slow magneto-acoustic waves can be da...
Underwater Acoustic Tomography (AT) system transmits acoustic waves into the water. The AT systems continuously measure the physical characteristics of the flow in rivers, seas and the oceans. The AT systems are synchronized via a GPS clock connectied to the satellites. Hence, the systems transmit the acoustic waves at the same time. The systems record the arrival time of acoustic waves. After ...
The behavior of linear and nonlinear dust acoustic waves (DAWs) in an unmagnetized plasma including inertialess electrons and positrons, ions, and mobile positive/negative dust grains are studied. Reductive perturbation method is employed for small and finite amplitude DAWs. To investigate the solitary waves, the Korteweg–de Vries (KdV) equation is derived and the solution is presented. B...
Received ; accepted – 2 – ABSTRACT Numerical simulations of galaxy clusters including two species – baryonic gas and dark matter particles – are presented. Cold Dark Matter spectrum, Gaussian statistics and flat universe are assumed. The dark matter component is evolved numerically by means of a standard particle mesh method. The evolution of the baryonic component has been studied numerically ...
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