SenSafe: A Smartphone-Based Traffic Safety Framework by Sensing Vehicle and Pedestrian Behaviors

Traffic accident involving vehicles is one of the most serious problems in the transportation system nowadays. How to detect dangerous steering and then alarm drivers in real time is a problem. What is more, walking while using smartphones makes pedestrian more susceptible to various risks. Although dedicated short range communication (DSRC) provides the way for safety communications, most of vehicles have not been deployed with DSRC components. Even worse, DSRC is not supported by the smartphones for vehicle-to-pedestrian (V2P) communication. In this paper, a smartphone-based framework named SenSafe is developed to improve the traffic safety. SenSafe is a framework which only utilizes the smartphone to sense the surrounding events and provides alerts to drivers. Smartphone-based driving behaviors detection mechanism is developed inside the framework to discover various steering behaviors. Besides, the Wi-Fi association and authentication overhead is reduced to broadcast the compressed sensing data using the Wi-Fi beacon to inform the drivers of the surroundings. Furthermore, a collision estimation algorithm is designed to issue appropriate warnings. Finally, an Android-based implementation of SenSafe framework has been achieved to demonstrate the application reliability in real environments

The hybridization of Ag2CO3 rods with g-C3N4 sheets with improved photocatalytic activity

A series of graphitic carbon nitride/silver carbonate (g-C3N4/Ag2CO3) rod-like composites with different weight contents of g-C3N4 have been prepared by a facile precipitation method. The g-C3N4/Ag2CO3 rod-like composites exhibited higher photocatalytic activity than pure Ag2CO3 toward degradation of rhodamine B (RhB) and methylene blue (MB) under visible-light irradiation. The photocatalytic reaction follows a pseudo-first-order reaction and the rate constants for the degradation of RhB and MB by 3.5% g-C3N4/Ag2CO3 are about 2 times and 1.7 times that of pure Ag2CO3, respectively. A possible photocatalytic mechanism was proposed based on the photoluminescence (PL) spectra and a series of radical trapping experimental analyses. The remarkably improved photocatalytic performance should be ascribed to the heterostructure between Ag2CO3 and g-C3N4, which greatly promoted the photoinduced charge transfer and inhibited the recombination of electrons and holes

Spatio-Temporal Variations of Zooplankton and Correlations with Environmental Parameters around Tiaowei Island, Fujian, China

The present study illustrates zooplankton dynamics in relation to environmental factors from the surrounding area of Tiaowei Island based on ten seasonal sampling cruises over three years. A total of 116 species of zooplankton were collected with a predominance of Copepoda (mainly consisting of Centropagidae, Oithonidae, Acartia, Labidocera and Paracalanus), accounting for 31.6 % of the total number of species. The diversity indices indicated a relatively high richness, abundance and evenness of zooplankton ranging from 2.794 to 4.012 on the Shannon–Wiener index for each cruise. More than 20 species of Cnidaria medusae are found as gelatinous organisms, which not only compete with fish but also potentially cause disasters. Significant seasonal variations were detected in both the zooplankton structure and environmental variables. NMDS illustrated a highly overlapping community structure in spring, autumn and winter, while the zooplankton composition in the summer was different from that of the other three seasons with a higher diversity index. Meanwhile, out of thirteen environmental parameters, eight varied significantly among seasons but there were no significant variations among stations. The biota–environmental relationship following a redundancy analysis revealed that water temperature, pH, salinity, dissolved oxygen and suspended particulate composition were the main environmental parameters, seasonally impacting the zooplankton communities. Planktonic larvae (such as nauplius larvae and branchyura zoea) and some zooplankton (including Corophium sinensis and Oithonasimilis) were significantly vulnerable to the dynamics of suspended particulate composition and water temperature

Copper single-atom catalysts with photothermal performance and enhanced nanozyme activity for bacteria‐infected wound therapy

Nanozymes have become a new generation of antibiotics with exciting broad-spectrum antibacterial properties and negligible biological toxicity. However, their inherent low catalytic activity limits their antibacterial properties. Herein, Cu single-atom sites/N doped porous carbon (Cu SASs/NPC) is successfully constructed for photothermal-catalytic antibacterial treatment by a pyrolysis-etching-adsorption-pyrolysis (PEAP) strategy. Cu SASs/NPC have stronger peroxidase-like catalytic activity, glutathione (GSH)-depleting function, and photothermal property compared with non-Cu-doped NPC, indicating that Cu doping significantly improves the catalytic performance of nanozymes. Cu SASs/NPC can effectively induce peroxidase-like activity in the presence of H2O2, thereby generating a large amount of hydroxyl radicals (•OH), which have a certain killing effect on bacteria and make bacteria more susceptible to temperature. The introduction of near-infrared (NIR) light can generate hyperthermia to fight bacteria, and enhance the peroxidase-like catalytic activity, thereby generating additional •OH to destroy bacteria. Interestingly, Cu SASs/NPC can act as GSH peroxidase (GSH-Px)-like nanozymes, which can deplete GSH in bacteria, thereby significantly improving the sterilization effect. PTT-catalytic synergistic antibacterial strategy produces almost 100% antibacterial efficiency against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). In vivo experiments show a better PTT-catalytic synergistic therapeutic performance on MRSA-infected mouse wounds. Overall, our work highlights the wide antibacterial and anti-infective bio-applications of Cu single-atom-containing catalysts

Quantitative Study of Charge Carrier Dynamics in Well-Defined WO3 Nanowires and Nanosheets: Insight into the Crystal Facet Effect in Photocatalysis

Photocatalysts with different morphologies and specific exposed facets usually exhibit distinguished activities. Previous researches have focused on revealing the essence of the facet effect in photocatalysis; however, quantitative analyses on the differences of carrier dynamic between different facets are scarce. Herein, we successfully synthesized WO3 nanosheets and nanowires with dominant exposed facets of {001} and {110}, respectively. The lower hole effective mass on {110} (0.94m(0)) than on {001} (1.28m(0)) calculated by density functional theory leads to the higher hole mobility on {110} (4.92 cm(2) V-1 s(-1)) than on {001} (3.14 cm(2) V-1 s(-1)). Combined with the Einstein equation and the lifetime of the hole, the calculated hole diffusion length on {110} (74.8 nm) is larger than on {001} (53.4 nm). Overall, the lower hole effective mass, higher hole mobility, and greater hole diffusion length on {110} collectively result in a photocatalytic activity on benzyl alcohol oxidation 2.46 times as high as that on {001}.</p

Interfacial π–p Electron Coupling Prompts Hydrogen Evolution Reaction Activity in Acidic Electrolyte

The thermodynamically stable 2H-phase MoS2 is a brilliant material toward hydrogen evolution reaction (HER) owing to its excellent Gibbs free energy of hydrogen adsorption. Nevertheless, the poor intrinsic properties of 2H-MoS2 limit its electrocatalytic performances toward HER. In this work, graphitic carbon nitride covalently bridging 2H-MoS2 (MoS2/GCN) is proposed to construct robust HER electrocatalysts. The strong π–p electron coupling between the delocalized π electrons of GCN and the localized p electrons of S atoms sufficiently expose active sites and accelerate the reaction kinetics. To be specific, MoS2/GCN exhibits remarkable HER activity (160 mV at 10 mA·cm–2) and long-term durability. Importantly, MoS2/GCN also provides great potential for industrial application. Density functional theory (DFT) calculations disclose that the π–p electron coupling at the MoS2/GCN interface regulates the electronic structure of S atoms, consequently providing enhanced HER performance. This work presents a feasible pathway to develop advanced electrocatalysts for energy conversions

Interfacial π–p Electron Coupling Prompts Hydrogen Evolution Reaction Activity in Acidic Electrolyte

The thermodynamically stable 2H-phase MoS2 is a brilliant material toward hydrogen evolution reaction (HER) owing to its excellent Gibbs free energy of hydrogen adsorption. Nevertheless, the poor intrinsic properties of 2H-MoS2 limit its electrocatalytic performances toward HER. In this work, graphitic carbon nitride covalently bridging 2H-MoS2 (MoS2/GCN) is proposed to construct robust HER electrocatalysts. The strong π–p electron coupling between the delocalized π electrons of GCN and the localized p electrons of S atoms sufficiently expose active sites and accelerate the reaction kinetics. To be specific, MoS2/GCN exhibits remarkable HER activity (160 mV at 10 mA·cm–2) and long-term durability. Importantly, MoS2/GCN also provides great potential for industrial application. Density functional theory (DFT) calculations disclose that the π–p electron coupling at the MoS2/GCN interface regulates the electronic structure of S atoms, consequently providing enhanced HER performance. This work presents a feasible pathway to develop advanced electrocatalysts for energy conversions

Quantitative Study of Charge Carrier Dynamics in Well-Defined WO₃ Nanowires and Nanosheets: Insight into the Crystal Facet Effect in Photocatalysis

Photocatalysts with different morphologies and specific exposed facets usually exhibit distinguished activities. Previous researches have focused on revealing the essence of the facet effect in photocatalysis; however, quantitative analyses on the differences of carrier dynamic between different facets are scarce. Herein, we successfully synthesized WO₃ nanosheets and nanowires with dominant exposed facets of {001} and {110}, respectively. The lower hole effective mass on {110} (0.94<i>m</i>₀) than on {001} (1.28<i>m</i>₀) calculated by density functional theory leads to the higher hole mobility on {110} (4.92 cm² V^–1 s^–1) than on {001} (3.14 cm² V^–1 s^–1). Combined with the Einstein equation and the lifetime of the hole, the calculated hole diffusion length on {110} (74.8 nm) is larger than on {001} (53.4 nm). Overall, the lower hole effective mass, higher hole mobility, and greater hole diffusion length on {110} collectively result in a photocatalytic activity on benzyl alcohol oxidation 2.46 times as high as that on {001}

Core–Shell ZIF-8@ZIF-67-Derived CoP Nanoparticle-Embedded N‑Doped Carbon Nanotube Hollow Polyhedron for Efficient Overall Water Splitting

The construction of highly active and stable non-noble-metal electrocatalysts for hydrogen and oxygen evolution reactions is a major challenge for overall water splitting. Herein, we report a novel hybrid nanostructure with CoP nanoparticles (NPs) embedded in a N-doped carbon nanotube hollow polyhedron (NCNHP) through a pyrolysis–oxidation–phosphidation strategy derived from core–shell ZIF-8@ZIF-67. Benefiting from the synergistic effects between highly active CoP NPs and NCNHP, the CoP/NCNHP hybrid exhibited outstanding bifunctional electrocatalytic performances. When the CoP/NCNHP was employed as both the anode and cathode for overall water splitting, a potential as low as 1.64 V was needed to achieve the current density of 10 mA·cm^–2, and it still exhibited superior activity after continuously working for 36 h with nearly negligible decay in potential. Density functional theory calculations indicated that the electron transfer from NCNHP to CoP could increase the electronic states of the Co <i>d</i>-orbital around the Fermi level, which could increase the binding strength with H and therefore improve the electrocatalytic performance. The strong stability is attributed to high oxidation resistance of the CoP surface protected by the NCNHP