let h be a separable hilbert space and let b be the set of bessel sequences in h. by using several interesting results in operator theory we study some topological properties of frames and riesz bases by constructing a banach space structure on b. the convergence of a sequence of elements in b is de_ned and we determine whether important properties of the sequence is preserved under the con...

heteropoly acids (hpa) and their salts have advantages as catalysts which make them both economically and environmentally attractive, strong br?nsted acidity, exhibiting fast reversible multi-electron redox transformations under rather mild conditions, very high solubility in polar solvents, fairly high thermal stability in the solid states, and efficient oxidizing ability, so that they are imp...

Characterization of structural woods in historical buildings has a great importance in technological study of applied details. Herein, seven historical buildings located in Alborz, Isfahan and eastern Azerbaijan provinces related to Safavid and Qajar periods have been assessed. Samplings were done from structural woods of the buildings. Samples were prepared, sectioned and evaluated by transiti...

In this paper, we study the phonon and thermal properties of a nanocrystal by using transfer matrix method in the harmonic approximation. The considered system is a mass-spring nanocrystal with a square cross section. At first, for the ideal case, we obtain the phonon spectrum with free boundary conditions. Then we calculate some phonon transport properties of this system, namely, the phonon de...

In this research, the effect of temperature and concentration of bismuth nitrate mole on structural, magnetic and photocatalytic properties of the bismuth ferrite nanoparticles prepared by nitrate-citrate method have been investigated. The structural and magnetic properties were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and vibrating-sample magneto...