A wavelength-division-multiplexing (WDM) visible light communiction (VLC) system employing red and green laser pointer lasers (LPLs) with directly modulating data signals is proposed and experimentally demonstrated. With the assistance of preamplifier and adaptive filter at the receiving sites, low bit error rate (BER) at 10 m/500 Mbps operation is obtained for each wavelength. The use of preamplifier and adaptive filter offer significant improvements for free-space transmission performance. Improved performance of BER of <10(-9), as well as better and clear eye diagram were achieved in our proposed WDM VLC systems. LPL features create a new category of good performance with high-speed data rate, long transmission length (>5m), as well as easy handling and installation. This proposed WDM VLC system reveals a prominent one to present its advancement in simplicity and convenience to be installed.

In this study, graphitic carbon nitride (g-C 3 N 4 ) nanosheets (CNns) were modified using polyaniline (PANI) codoped with an inorganic (hydrochloric acid, HCl) and an organic (phytic acid, PA) acid. Our results revealed that these samples exhibited extended visiblelight absorption and a three-dimensional (3D) hierarchical structure with a large specific surface area. They also inhibited photoluminescence emission, reduced electrical resistance, and provided abundant free radicals, resulting in high photocatalytic performance. The PANI/g-C 3 N 4 sample demonstrated outstanding photocatalytic activity of a Cr(VI) removal capacity of 4.76 mg•min −1 •g c −1 , which is the best record for the reduction of a 100 ppm K 2 Cr 2 O 7 solution. Moreover, g-C 3 N 4 coupled with PANI monotonically doped with HCl or PA did not demonstrate increased activity, suggesting that the codoping of HCl and PA plays a significant role in enhancing the performance. The improved photocatalytic activity of PANI/g-C 3 N 4 can be attributed to the interchain and intrachain doping of PA and HCl over PANI, respectively, to create a 3D connected network and synergistically increase the electrical conductivity. Therefore, new insights into g-C 3 N 4 coupled with PANI and codoped by HCl and PA may have excellent potential for the design of g-C 3 N 4 -based compounds for efficient photocatalytic reactions.

A dynamic bandwidth assignment protocol is proposed that demonstrates impartial and highly efficient bandwidth arrangement for gigabit-capable passive optical networks. In particular the novel algorithm automatically modifies the assigned bandwidth per optical network unit to support quality of service and service level agreement according to maximum network capacity and users' queuing status. Network simulation results have demonstrated superior mean packet delay performance achieving a tenfold reduction of packet delay at high network load when compared to other dynamic bandwidth assignment algorithms.

Graphene supports long spin lifetimes and long diffusion lengths at room temperature, making it highly promising for spintronics. However, making graphene magnetic remains a principal challenge despite the many proposed solutions. Among these, graphene with zig-zag edges and ripples are the most promising candidates, as zig-zag edges are predicted to host spin-polarized electronic states, and spin–orbit coupling can be induced by ripples. Here we investigate the magnetoresistance of graphene grown on technologically relevant SiC/Si(001) wafers, where inherent nanodomain boundaries sandwich zig-zag structures between adjacent ripples of large curvature. Localized states at the nanodomain boundaries result in an unprecedented positive in-plane magnetoresistance with a strong temperature dependence. Our work may offer a tantalizing way to add the spin degree of freedom to graphene.

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Summary Entanglement properties of IBM Q 53‐qubit quantum computer are carefully examined with the noisy intermediate‐scale quantum technology. We study Greenberger‐Horne‐Zeilinger‐like states with multiple qubits (N = 2 to N = 7) on IBM Rochester and compare their maximal violation values of Mermin's polynomials with analytic results. A rule of N‐qubits orthogonal measurements is taken to further justify the entanglement less than maximal values of local realism. The orthogonality of measurements is another reliable criterion for entanglement except the maximal values of LR. Our results indicate that the entanglement of IBM 53 qubits is reasonably good when N ≤ 4, while for the longer entangle chains, the entanglement is only valid for some special connectivity.

We report a facile, fast, and one-step approach to prepare N-doped graphene quantum dots (GQDs) using pulsed laser ablation with diethylenetriamine (DETA). The synthesized N-doped GQDs with an average size of about 3.4 nm and an N/C atomic ratio of 26% have been demonstrated. Compared to pristine GQDs, the N-doped GQDs emit enhanced photoluminescence (PL) with a factor as high as 66, originated from the enhanced densities of pyridinic and graphitic N. The temperature-dependent PL of the N-doped GQDs was studied from cryogenic to room temperature. An anomalous temperature dependence of PL intensity was observed for the N-doped GQDs, which was ascribed to a carrier transfer mechanism from a dopant-induced state to the quantum-dot emitting state.

Lanthanum-modified zeolitic imidazolate framework (La/ZIF-8) was developed to produce glycerol carbonate using CO2 and glycerol as raw materials. La/ZIF-8 provides a high catalytic glycerol conversion efficiency owing to its surface-attached...