RESUMEN
Photocatalytic ozonation, which combines the effects of lighting and ozonation, has been shown to enhance the decolorization and degradation of organic pollutants in wastewater. Dye solutions with concentrations of 10 ppm for both methylene blue and methyl orange dyes were used. The influence of ozoneation on the performance of photocatalytic activity of TiO2 and ZnO nanoparticles for the removal of organic dyes from aqueous solutions was investigated. To evaluate their efficacy for the removal of methylene blue and methyl orange dyes from aqueous solutions, the photocatalysts were exposed to UV light for 90 min, with ozone supplied either intermittently or continuously by an SDBD cold plasma reactor. The photocatalysts utilized in this study were characterized using SEM and XRD techniques. The degree of color degradation was determined using UV-Vis spectroscopy. The results demonstrate that TiO2 and ZnO nanoparticles exhibit different degrees of photocatalytic activity for the two dyes. The addition of ozone was found to enhance both the color degradation and mineralization rates of the pollutants, with intermittent ozonation proving more effective than continuous ozonation. The most significant color degradation results were obtained using TiO2 nanoparticles with intermittent ozonation for methylene blue dye (97 %) and ZnO nanoparticles with intermittent ozonation for methyl orange dye (40 %). Overall, this study provides evidence that photocatalytic ozonation represents a promising technique for water treatment.
RESUMEN
In this study, three flexible metal-semiconductor-metal ultraviolet photodetectors are fabricated on the FR4 fiberglass substrate based on the porous zinc oxide by radiofrequency sputtering. Their copper electrodes were created by printed circuit board, a simple and cheap method. Here, the effect of porosity on the photodetector parameters is discussed. The results show that the difference in the finger size in the photodetectors leads to differences in the parameters. In these photodetectors, as the fingers increase in length, dark current increases from 0.25 to 67.3 µA, photocurrent from 1.98 to 208 µA, and response time from 430 to 570 ms. Also, with expanding finger width, these parameters changed 18.48 µA, 26.8 µA, and 440 ms, respectively.
RESUMEN
In this study, the effect of electrode shape difference on the height of the Schottky barrier and the electric field in flexible photodiodes (PDs) has been investigated. For this purpose, three different electrode designs were prepared on three flexible FR4 layers that were coated with Zinc Oxide (ZnO). The printing circuit board (PCB) method was used to create these copper electrodes. The asymmetry of the PD electrodes and the difference in the height of the Schottky barrier has led to the creation of self-powered PDs. The effect of the amount and shape of the distribution of internal electric fields generated in the PDs and its effect on the parameters of the PDs has been investigated with the help of simulations performed in COMSOL software. The photocurrent of the sample with circular and rectangular electrodes was equal to 470 µA in 15 V bias, which was twice as good as a sample with an interdigitated MSM structure. Also, this sample had the best response time among these three samples, which was equal to 440 ms.
RESUMEN
III-Nitride bandgap and refractive index data are of direct relevance for the design of (In, Ga, Al)N-based photonic and electronic devices. The bandgaps and bandgap bowing parameters of III-nitrides across the full composition range are reviewed with a special emphasis on InxAl1-xN, where less consensus was reached in the literature previously. Considering the available InAlN data, including those recently reported for low indium contents, empirical formulae for InAlN bandgap and bandgap bowing parameter are proposed. Applying the generalised bandgap data, the refractive index dispersion data available in the literature for III-N alloys is fitted using the Adachi model. For this purpose, a formalism involving a parabolic dependence of the Adachi parameters on the dimensionless bandgap [Formula: see text] of the corresponding ternary alloys is used rather than one directly invoking the alloy composition.
RESUMEN
In this paper, on the basis of the extended Huygens-Fresnel principle, a semi-analytical expression for describing the on-axis scintillation index of a partially coherent flat-topped laser beam through non-Kolmogorov maritime and terrestrial atmospheric environments on a slant path is derived. Consequently, by using the log-normal intensity probability density function, the bit error rate (BER) is evaluated. The effects of source factors (such as wavelength, order of flatness, and beam width) and the non-Kolmogorov turbulent atmosphere parameters (such as the Kolmogorov inner scale, the spectral power-law exponent, and the turbulence structure constant) on propagation behavior of the scintillation index, and hence on the BER, are studied in detail. Results indicate that an increase in the average SNR causes a greater influence of the power-law exponent on the BER. Also, it can be deduced that the mean BER increases while the power-law exponent decreases. In addition, the scintillation index and BER as communication link parameters represent the fact that increasing the atmospheric refractive-index structure parameter on the ground and decreasing the inner scale of turbulence eddies causes an increase in these parameters.