By the method of green synthesis, silver nanoparticles were obtained in colloidal solutions. The solutions were modified with thulium ions. Using the method of electron microscopy and optical method, the properties of silver nanoparticles obtained are studied. The influence of change in concentration of the solution of mint and thulium ions on the properties of colloidal silver nanoparticles was studied.
Recently, research has been developing on nanoscale objects (a group of atoms) for which the concept of dielectric constant has a conventional meaning and therefore requires refinement and even analysis. In this paper we analyze the change in the intensity of Raman scattering of nanoobjects placed on a flat substrate. Some variants were shown for which the scattering can vary by more than an order of magnitude. In particular, on an ideal metal substrate, the region of antinode of a standing light wave upon reflection does not extend to the near-surface layer in which the nanoobject is located. And for this reason the Raman scattering decreases by more than an order of magnitude. Conditions are shown under which a decrease in Raman scattering from nanoobjects can be compensated and even increased.
The main approximations for calculation of effective parameters of inhomogeneous media are Bruggeman effective medium approximation and Maxwell Garnett model, which are currently widely used in the description of composites containing various nanostructured objects. In this paper we consider a simple approach to these approximations, allowing to embrace the most general case of statistically anisotropic media with particles of arbitrary internal structure, and also to clarify their physical meaning. The type of result essentially depends on the choice of "effective cells" used in estimating the field and induction values averaged over the volume.
The effect of sediment flotation was observed in dispersion of graphene oxide flakes with Ag-particles deposited thereon in the aqueous-organic (containing dimethylformamide) under the visible light action, with subsequent stabilization of the dispersion, which does not occur in the absence of Ag-particles. The main reason for this laser light induced movement of sediment graphene oxide flakes may be associated with the appearance of small bubbles. The further development of this approach seem to be able to estimate the of graphene flakes photoactivity with different activating particles.
The influence of thermolysis time on the absorption spectra of partially thermally dehydrochlorinated polyvinyl chloride in acetophenone solution is studied. Strong increase in the optical density Dλ of the dehydrochlorinated PVC samples is caused by the increasing amount N-C=С- and the length of chains of conjugated double bonds of carbon -C = C-. It is noted that the optical density Dλ first increases linearly with dehydrochlorination time and then reaches saturation. The estimation of amount of double conjugated carbon bonds in 1ml versus thermolysis time t is given, which varies between N-С=С- = 4·1017 – 7.4·1018 for t from 40 to 420 minutes. The effective capture cross section of a photon on conjugated double bonds of carbon for dehydrochlorinated PVC solution in acetophenone is estimated, which was about 10-17 cm2 . The analysis is done of the absorption curves «red» shift to longer wavelengths with growth of N-С=С- upon increase of thermolysis time. It is noted that the dependence of the optical density on the wavelength in this range is well described by a simple exponential function.
The generalization of classic Lorentz -Lorenz formula (LLF) is obtained for
effective perrnittivity of a medium with non -point correlated particles. It follows from
the regular procedure developed, and takes into account particle correlations. Instead
of polarizability of point dipole it contains the T -operator of scattering on non -point
scatterer. When this operator is taken in dipole approximation and all correlation are
neglected, it reduces to LLF. In the case of rarefied media it gives known results,
described by van de Hulst formula.
New small angle equations are derived for polarized wave propagation in media with turbulence and precipitations (i.e. continuous fluctuations and discrete inclusions). These equations generalize the usual scalar parabolic equation and enable one to investigate simultaneously effects due to both discrete and continuous fluctuations.
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