RESUMEN
In the present research work, we employed the transfer matrix method (TMM) in addition to MATLAB software to examine the transmission properties of various organic-based one-dimensional (1D) magnetic cold-plasma photonic crystals (MCPPhCs). The proposed structures were found to be made up of periodic layers of organic materials and magnetic cold-plasma (MCP) at normal incidence. An external magnetic field (B) polarized in right-hand (RH) and left-hand (LH) configurations was applied on 1D MCPPhCs. In this study, four organic materials, namely pentane, hexane, heptane, and octane, were chosen to design four 1D photonic crystals (PCs), named as PC1 (pentane-MCP), PC2 (hexane-MCP), PC3 (heptane-MCP), and PC4 (octane-MCP). Our results indicated that the central frequency of the resonant peaks of unit transmission inside the photonic band-gap (PBG) of the respective organic PCs could be tuned towards the higher or lower frequency side by applying B polarized in RH and LH configurations, respectively. We also studied the effect of the period number N to produce closely spaced N-1 transmission channels of unit transmission inside the PBG of all four organic PCs. By increasing the period number N we could increase the number of transmission channels inside the PBG as per our desire. These multiple resonant peaks of unit transmission inside PBG could be easily modulated inside the PBG to accommodate new frequencies by applying B polarized in either RH or LH configurations, respectively. Moreover, our results showed that under the RH configuration, increasing B resulted in a shifting of the resonant peak towards the higher frequency side with a reduction in its full width half maximum (FWHM), whereas the findings were the opposite in the case of increasing B under the LH configuration. These findings may be beneficial for designing externally tuneable organic chemical sensors in the microwave frequency region.
RESUMEN
Organic-compound-based sensors have important applications, such as applications in geothermal power stations, the shoe industry, the extraction of vegetable oil, azeotropic calibration and medical science. Herein, a 1D photonic crystal (PC) with a defect has been used to develop a photonic-technology-based organic compound sensor with optimum performance. The structure of the proposed organic compound sensor consists of a water cavity sandwiched between two symmetric sub-PCs, which are composed of alternate layers of SiO2 and ZnO. The proposed air/(SiO2/ZnO)5/cavity/(SiO2/ZnO)5/glass structure with the optimized structural parameters achieves a quality factor that varies between a minimum value of 4968.2 and a maximum value of 6418.5. The FOM and sensitivity values of the proposed sensing design are on the order of 102 and 103, respectively. The LOD value of the proposed sensor is on the order of 10-5, which is very low, as is always expected for chemical sensing designs. Thus, the simple design and excellent performance make our design highly efficient and suitable for sensing applications in the industrial and biomedical fields.
RESUMEN
This study focuses on spatiotemporal variations in the type of dissolved organic matter (DOM) and copper binding ability both upstream and downstream of Paris. It also compares the relative influence of both natural DOM upstream of Paris and effluent dissolved organic matter (EfDOM) output from a wastewater treatment plant (WWTP) on trace metal speciation and bioavailability in aquatic systems. In addition to the typical high- and low-affinity binding sites, a third family of very high-affinity binding sites has been highlighted for EfDOM. In receiving waters downstream of Paris during low-flow periods, the percentage of high- and very high-affinity sites originating from EfDOM reaches nearly 60 %. According to the speciation computation, the free copper concentration upstream of Paris exceeds the downstream Paris concentration by a factor of 2 to 4. As regards copper bioavailability, the highest EC50tot values were observed for EfDOM and downstream DOM, with a very low aromaticity and low UV absorbance. This finding suggests that specific ultraviolet absorbance (SUVA) is unlikely to be useful in assessing metal speciation and toxicity in aquatic systems subject to strong urban pressures. These results also highlight that the copper speciation computation for surface water exposed to considerable human pressures should include not only the humic and/or fulvic part of dissolved organic carbon but more hydrophilic fractions as well, originating for example from EfDOM.
