Due to the inertness of the SiC material to the chemical impact, creating a porous layer on the SiC thin films and especially on non-doped amorphous SiC (aSiC) thin films is a very difficult task. To overcome this difficulty, one solution is using surface activation substances. In this report we present a study of the role of the Triton X-100 (TX100) added to the HF/H2O electrolyte in fabricating a porous layer with the size of pores in the nanometer region on the aSiC thin films by the electrochemical etching method. The results showed that, in general TX100 is effective for porous etching. However, for differently doped aSiC materials (non-doped, n-doped and p-doped), TX100 has different levels of effect. TX100 reveals a prominent role in porous etching of n-doped aSiC, with higher concentration of TX100 giving greater porosity. Meanwhile, although TX100 also acts as a support to the porous etching of non-doped aSiC, its various concentrations in the region of 0.05-1% give the same porosity. At last, TX100 has no effect in porous etching of p-doped aSiC.
In this paper, we have investigated tilted cosmological models with the scalar-tensor theory of gravitation proposed by Wesson. The Kantowski-Sachs metric with a time-dependent gauge function is described by considering the tilted cosmological models. Some geometric aspects of the model are also discussed.
A theoretical investigation has been made to study the cylindrical and spherical electron-acoustic shock waves (EASWs) in an unmagnetized, collisionless degenerate quantum plasma system containing two distinct groups of electrons (one inertial non-relativistic cold electrons and other inertialess ultra-relativistic hot electrons) and positively charged static ions. By employing well known reductive perturbation method the modified Burgers (mB) equation has been derived. It is seen that only rarefactive shock waves can propagate in such a quantum plasma system. The effects of degenerate plasma pressure and number density of hot and cold electron fluids, nonplanar geometry, and positively charged static ions are responsible to modify the fundamental properties of EASWs. It is also observed that the properties of planar mB shocks are quite different from those of nonplanar mB shocks. The findings of the present investigation should be useful in understanding the nonlinear phenomena associated with nonplanar EAWs in both space and laboratory plasmas.
In this paper, we have studied the optical properties of the poly(methylmethacrylate) (PMMA) polymer doped with Solochrome Dark Blue dye as solid films. The nonlinear optical properties of these films were measured by using the z-scan technique with continuous wave (CW) solid-state laser operating at wavelength 532 nm. The nonlinear refractive index (n2), the nonlinear absorption coefficient (β), and the real and imaginary parts of the third-order nonlinear optical susceptibility (χ (3)) were investigated at different dye concentrations. The optical power limiting behavior was also investigated for different dye concentrations. Our experimental results showed that the Solochrome Dark Blue dye-doped polymer films exhibit large optical nonlinearities, hence are suitable for applications on photonic devices and optical limiters.
In this paper, we studied the efficiency of defining the subspace of the slow protein motion for describing long time scale dynamics. To address the problem of the correlations between the slow and the fast modes, we investigated the separation of time scales provided by the Principal Component Analysis (PCA) method. In our study, two systems have been discussed, the C2 fragment of the G protein (56 amino acids) and the Fc domain of IgG protein (206 amino acids). Our results indicated that only little convergence is obtained at a sub nanosecond time scale for large proteins, whereas pronounced convergence sets in for small proteins at the 5 ns time scale. This finding, together with the demonstrated separation of time scales, suggests that PCA provides indeed suitable subspaces for a dimension reduced description of protein dynamics in long time scales.