Chandra Galactic Center Survey detected nearly 1000 X-ray point-like sources in the 2×0.8 sky region around the Galactic Center. The corresponding area is about 280 × 110 pc at a distance of 8 kpc. In this paper, we study the spatial and luminosity distributions of these sources according to their spectral properties. Eighteen bright sources detected are used to fit jointly an absorbed power-la...

Compton scattering by a locally plane parallel atmosphere is analyzed within the Kompaneets approximation. In contrast to almost all previous analytic calculations of inverse Compton scattering, we assume neither homogeneity nor isotropy of the photon distribution. However, we do adopt an assumed angular distribution of the photons. For any specified energy dependence of the flux entering the b...

We argue that an experimental search for an η ′ c , the first radial excitation of the η c (2980), may be carried out using the two photon process e + e − → e + e − γγ → e + e − η ′ c. We estimate the partial width Γ γγ (η ′ c) and the branching fraction B(η ′ c → h), where h is an exclusive hadronic channel, and find that for h = K o s K ± π ∓ it may be possible to observe this state in two ph...

We calculate the statistical distribution P2(I2) of the speckle pattern produced by a photon pair current I2 transmitted through a random medium, and compare it with the single-photon speckle distribution P1(I1). We show that the purity of a two-photon density matrix can be directly extracted from the first two moments of P1 and P2. A one-to-one relationship is derived between P1 and P2 if the ...

the hydration of biomolecules is vitally important in molecular biology, so in this paper thesolvation energy and radial distribution function of dna bases have been calculated by themonte carlo simulation.the geometries of isolated adenine, guanine, cytosine, and thyminehave been optimized using 6-31+g(d,p) basis function sets. these geometries then will be used inthe monte carlo calculation o...

This research develops thermo-elastic analysis of a functionally graded cylinder under thermo-mechanical loadings. Heat conduction equation in cylindrical coordinate system is solved. Thermal conductivity coefficient is graded along the radial direction. By considering a symmetric distribution of temperature, loading and boundary conditions, strain-displacement and stress-strain relations can b...

We demonstrate that cylindrical vector beams with radial and azimuthal polarization states can be generated by leaky emission from photoexcited molecules embedded in slab-optical-waveguides which are formed on thin metal films on glass. Mirrorless lasing action in the optical waveguide leads to an order-of-magnitude collapse of the emission energy bandwidth and an emission directionality enhanc...