A two-stream description of the interaction of radiation with vegetation and soil is tested with experimental data for a corn canopy. The results indicate that the two parameters of the theory (reflectance of a dense canopy and the attenuation coe~cient for radiation in the canopy) can be estimated for the Thematic Mapper spectral bands. A collection of soil reflectance data is used to develop ...

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 benefit of finding particular exact and asymptotic solutions of non-integrable non-linear partial differential equations is considered. It is shown how explicit analytical solutions predict important features of the waves behavior even outside their formal applicability. In particular, an arbitrary initial pulse splits in a numerical solution into the train of localized waves each described...