Aiming at the acoustic attenuation in salt-cavern environment, this paper established a theoretical relationship of ultrasonic gas storage, based on wave equation propagating non-ideal medium, and considering specific environment analyzes how wall roughness storage affects attenuation. The results show that inner has an effect surface is solid-liquid interface, where change medium will affect w...

In this paper, we have reported the fabrication of two-dimensional photonic crystals, using a direct writing method in azo polymers. Periodic structures have been fabricated using the interference patterns of two coherent laser beams. The frequency response of the initial one-dimensional structure shows an attenuation of 19.3dB at 1554nm. The twodimensional structure shows 8.3dB and 11.3dB of a...

introduction: monte carlo (mc) is the most common method for simulating virtual spect projections. it is useful for optimizing procedures, evaluating correction algorithms and more recently image reconstruction as a forward projector in iterative algorithms; however, the main drawback of mc is its long run time. we introduced a model based method considering the effect of body attenuation and i...

introduction: the photoelectric attenuation coefficient of substances is known to depend upon the energy e of the photon and the effective atomic number of substances (zeff) as (zeff x /e y ).  no definitive values about these indices x, y are given in the literature. the index x is said to lie between, 3.0 and 4.0, while for ‘y’ different values have been assigned, between 3.0 and 4.0. methodo...

background: radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. materials and methods: the measurement has been performed using gamma spectrometer contains nai (tl) detector at the photon energies of 662, 1173 and 1332 ke...

the sporozoites of theileria annulata invade bovine mhc ii cells, where they differentiate into schizonts. the later can immortalize and induce fundamental changes in their host cells. live attenuated vaccine is an important way of controlling t. annulata infection of cattle. production is by prolonged cultivation of macroschizont-infected cells. the mechanisms underlying this transformation ar...