A practical graphitic carbon nitride (g-C₃N₄)based fluorescence sensor for the competitive detection of trithiocyanuric acid and mercury ions

[EN] A fluorescent sensor for the detection of trithiocyanuric acid (TCA) and Hg was developed based on competitive interactions: non-covalent stacking between g-CN and TCA vs coordinative interaction between TCA and Hg. Electrostatic simulations were used to evaluate the interactions and help describe the detection mechanism. Moreover, normalized 2D fluorescence contour plots have been used to understand the fluorescence phenomenon. When TCA was added into a g-CN nanosheet solution free of Hg, TCA interacted with g-CN nanosheets via hydrogen bonding and π-π interactions, resulting in fluorescence quenching of the g-CN nanosheets. However, upon the addition of Hg, the fluorescence of the TCA-g-CN nanosheet hybrid system was restored, due to coordination of Hg with TCA through the S atoms, breaking the TCA-g-CN stacking interaction. Our results provide a new approach for the design of multifunctional nanosensors suitable for the detection of environmental pollutants.The present work is supported by the National Natural Science Foundation of China (No. 21607044), the Natural Science Foundation of Hebei Province (No. B2017502069) and the Fundamental Research Funds for the Central Universities (No. 2018MS113). All data sup-porting this study are provided as supplementary information accom-panying this paper. T.D.J. wishes to thank the Royal Society for a Wolfson Research Merit Award

BlindDate: A neighbor discovery protocol

Many wireless applications urgently demand an efficient neighbor discovery protocol to build up a bridge connecting users to service providers or to other users. However, due to intrinsic constraints of wireless devices, e.g., limited energy and error of clock synchronization, there is still absence of effective and efficient neighbor discovery protocols in the literature. In this work, we propose neighbor discovery protocols for the following two problems. We first study Asynchronous Symmetry Neighbor Discovery problem, in which potential neighbor devices with asynchronous time clock but the same duty cycle aim to find each other. We further propose an efficient protocol (using Bouncing strategy) named BlindDate with guaranteed worst-case performance 9 10 (1 + δ)2x2 where δ is a small fraction of the length of time slot unit and 1 x is the duty cycle. Next, we extend this design to address Asynchronous Asymmetry Neighbor Discovery problem, in which both time clock and the duty cycles of potential neighbors are considered to be heterogeneous. We conduct extensive simulations to examine the feasibility and efficiency of the proposed protocols. Results show that BlindDate protocol outperforms existing approaches in average-case. We conclude that, compared with known protocols, BlindDate achieves a better worstcase discovery latency bound (e.g., 10% performance gain comparing with Searchlight [1]). © 2013 IEEE