Graphene oxide (GO) and its reduced form, reduced graphene oxide (rGO), are among the most predominant graphene derivatives because their unique properties make them efficient adsorbent nanomaterials for water treatment. Although extra-functionalized GO and rGO are customarily employed for the removal of pollutants from aqueous solutions, the adsorption of heavy metals on non-extra-functionalized oxidized graphenes has not been thoroughly studied. Herein, the adsorption of mercury(II) (Hg(II)) on eco-friendly-prepared oxidized graphenes is reported. The work covers the preparation of GO and rGO as well as their characterization. In a further stage, the description of the adsorption mechanism is developed in terms of the kinetics, the associated isotherms, and the thermodynamics of the process. The interaction between Hg(II) and different positions of the oxidized graphene surface is explored by DFT calculations. The study outcomes particularly demonstrate that pristine rGO has better adsorbent properties compared to pristine GO and even other extra-functionalized ones.

Graphene is a thin-film carbon material that has immense potential as a key ingredient in new nanoelectronic and nanophotonic devices due to its unique characteristics. In particular, plasmons in graphene appear as a practical tool for the manipulation of light with potential applications from cancer treatment to solar cells. A motivating tunability of graphene properties has been observed in graphene nanoribbons (GNRs) due to their geometrically controllable bandgaps that, in turn, influence the plasmonic properties. The formidable effort made over recent years in developing GNR-based technologies is, however, weakened by a lack of predictive approaches that draw upon available semi-analytical electromagnetic models. An example of such a framework is used here, focusing on experimentally realized GNRs from 155 to 480 nm wide and organized as two-dimensional (2D) GNR arrays. The results show that the plasmon frequency behavior is highly affected by the experimental setup or geometrical factors. In particular, the bandgap of the analyzed systems is of the order of a few meV with a density of states opening around zero energy (Fermi level) in contrast to what is observed in graphene. From the plasmonic part, it is observed in all 2D GNR arrays that the frequency–momentum trend follows a -like plasmon dispersion whose plasmon frequency can be increased substantially by increasing the ribbon width or charge density concentration. Forbidden plasmon regions are observed for high values of plasmon excitation angle or electron relaxation rate. From a sensing point of view, the important finding is the fact that 2D GNR arrays of 155 nm wide with high values of electron relaxation rate have plasmon responses similar to those observed for thrombin in water. Our predictions are projected to be of fast support for detecting plasmons in more complex designs of ribbon nanodevices with potential applications in molecular sensing of aqueous molecules.

Multibeam antenna (MBA) systems operating in the millimeter-wave frequency bands have drawn significant attention from researchers and are being effectively studied due to the demanding system needs for the fifth-generation (5G) wireless communication systems and the drastic spectrum scarcity at the existing cellular frequency range. To enable a greater transmission speed, an enhanced signal-to-interference-plus-noise ratio, an enhanced spectral and energy performance, and flexible beam shaping, they serve as the primary antenna technology. They offer tremendous potential for serving as the crucial infrastructure for facilitating beamforming and massive multiple-input multiple-output (MIMO) which uplift the 5G. To achieve this, a novel beamforming design and optimization approach based on the Convex Time Modulated Particle Swarm Optimization (CTM-PSO) algorithm is suggested for 5G communication networks, offering multiple concurrent transceivers to support efficient beamformed interactions whereas a second beam concurrently detects the atmosphere around the base-station. The suggested beamforming method combines the optimization of the transmitter and receiver beamforming weights to increase sensor performance, reduce potential intervention resulting from the communication beams, and ensure the communications link's target beamforming gains. Comprehensive numerical assessments are used to evaluate the effectiveness of the recommended method, showing that it may provide significant improvements over more conventional beamforming methods.

Data transmission is the process of transmitting digital information from one device to another over a network. With the increasing demand for high-speed data transmission and the proliferation of connected devices, the development of advanced data transmission technologies and networks has become crucial. This paper reviews the most commonly used data transmission technologies and networks, including wired and wireless technologies, and highlights their advantages and limitations.