We present an observational and theoretical study of the spiral structure in galaxy NGC 1566. A digitized image of NGC 1566 in I-band, obtained with the Australian National University 30in telescope, was used for measurements of the radial dependence of amplitude variations in the spiral arms. The azimuthal variations of the surface brightness in the I-band are about ±7 % at 50 radius and incre...

graphite oxide constitutes carbon network with oxygen atoms both on hexagonal arrangement and the edge sites. structural and electronic properties for graphite-oxygen complexes have been explored using first-principles total-energy calculations within the local density approximation (lda). band structures and density of states for the propose carbon 3d models are reported. a finite energy gap and...

In this paper, we report our experimental study on two-dimensional photonic crystal slabs embedded inside parallel-plate metal waveguides, using terahertz time-domain spectroscopy. We observe that the temporal response of the photonic crystal slabs is significantly dispersed, indicative of strong dispersion near the edges of the photonic band gap. In the frequency domain, we observe several gap...

by employing the theoretical method based on tight-binding, we study electronic band structure of single-wall carbon nanotube (cnt) superlattices, which the system is the made of the junction between the zigzag and armchair carbon nanotubes. exactly at the place of connection, it is appeared the pentagon–heptagon pairs as topological defect in carbon hexagonal network. the calculations are base...