Yurasov

The analysis of modifications of artificial crystals, having natural analogies, is interesting to nanophotonics. Carbon can be adsorbed in the opal. Carbon can change optical characteristics of crystallized opal. Reflection coefficient and spectrum of optical radiation can be changed. The goal of our article is assessment of influence of carbon concentration on optical characteristics. We used the original method of calculation using computer simulation. We obtained spectral dependence between reflection coefficient in different spectrum areas (near-infrared, visible, near ultraviolet) and different concentrations of carbon in opal. We justified our calculation method theoretically and experimentally.

 It is of great interest to analyze the limit of specific resistance of disordered alloys both for massive models and for thin films and small particles in porous medium, and also to examine its influence on high-frequency conductivity. This work is dedicated to solution of these problems. All calculations are carried out for the model of metal as a model of Fermi gas of electrons o condition that the free path is equal to the average bond radius. The authors obtained formulas for static and dynamic conductivity of thin films and small particles in porous medium which can be applied both for nonmagnetic and magnetic alloys. The authors stated the field of applicability of the obtained formulas. They proposed and justified a hypothesis about reasons of the quantum limit existence for conductivity of alloys which is independent of magnetic order.