Estimating long-term time-resolved indoor PM2.5 of outdoor and indoor origin using easily obtainable inputs

To evaluate the separate impacts on human health and establish effective control strategies, it is crucial to estimate the contribution of outdoor infiltration and indoor emission to indoor PM_2.5 in buildings. This study used an algorithm to automatically estimate the long-term time-resolved indoor PM_2.5 of outdoor and indoor origin in real apartments with natural ventilation. The inputs for the algorithm were only the time-resolved indoor/outdoor PM_2.5 concentrations and occupants’ window actions, which were easily obtained from the low-cost sensors. This study first applied the algorithm in an apartment in Tianjin, China. The indoor/outdoor contribution to the gross indoor exposure and time-resolved infiltration factor were automatically estimated using the algorithm. The influence of outdoor PM_2.5 data source and algorithm parameters on the estimated results was analyzed. The algorithm was then applied in four other apartments located in Chongqing, Shenyang, Xi'an, and Urumqi to further demonstrate its feasibility. The results provided indirect evidence, such as the plausible explanations for seasonal and spatial variation, to partially support the success of the algorithm used in real apartments. Through the analysis, this study also identified several further development directions to facilitate the practical applications of the algorithm, such as robust long-term outdoor PM_2.5 monitoring using low-cost light-scattering sensors.     

Lithiation MXene Derivative Skeletons for Wide-Temperature Lithium Metal Anodes

Lithium (Li) metal, as an appealing candidate for the next-generation of high-energy-density batteries, is plagued by its safety issue mainly caused by uncontrolled dendrite growth and infinite volume expansion. Developing new materials that can improve the performance of Li-metal anode is one of the urgent tasks. Herein, a new MXene derivative containing pure rutile TiO₂ and N-doped carbon prepared by heat-treating MXene under a mixing gas, exhibiting high chemical activity in molten Li, is reported. The lithiation MXene derivative with a hybrid of LiTiO₂-Li₃N-C and Li offers outstanding electrochemical properties. The symmetrical cell assembling lithiation MXene derivative hybrid anode exhibits an ultra-long cycle lifespan of 2000 h with an overpotential of ≈30 mV at 1 mA cm⁻², which overwhelms Li-based anodes reported so far. Additionally, long-term operations of 34, 350, and 500 h at 10 mA cm⁻² can be achieved in symmetrical cells at temperatures of −10, 25, and 50 °C, respectively. Both experimental tests and density functional theory calculations confirm that the LiTiO₂-Li₃N-C skeleton serves as a promising host for Li infusion by alleviating volume variation. Simultaneously, the superlithiophilic interphase of Li₃N guides Li deposition along the LiTiO₂-Li₃N-C skeleton to avoid dendrite growth.     

Freeze-drying and mechanical redispersion of aqueous PEDOT:PSS

Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films are attracting famous applications in antistatic coating, energy storage and conversion, printed electronics, and biomedical fields due to their conductivity, optical transparency and flexibility. However, PEDOT:PSS has poor dispersion stability during long-term storage and transport. Moreover, the dried PEDOT:PSS films are insoluble in any solvent and cannot be redispersed again. In comparison to bake drying, here, a feasible strategy to achieve mechanically redispersed PEDOT:PSS with the help of freeze-drying process was reported. The redispersed PEDOT:PSS can recover not only the initial characters such as pH, chemical composition, viscosity, and particle size under similar solid contents, but also conductivity and surface morphology of treated films. In addition, the treated film exhibits self-healing properties similar to pristine film in terms of mechanical and electrical properties. This technology enables reuse and overcomes the technical problems of PEDOT:PSS dispersion, realizing real-time processing to meet variable applications.     

Facile synthesis of MgO–Mg2SiO4 composite ceramics with high strength and low thermal conductivity

The recycling of solid waste is a win-win solution for humans and nature. For this purpose, magnesite tailings and silicon kerf waste were employed to prepare MgO–Mg₂SiO₄ composite ceramics by solid-state reaction synthesis in the present work. Then, effects of sintering temperature and raw material ratio on as-prepared ceramics were systematically studied. As-prepared ceramics showed improvement in their relative density (from 47.55%–68.12% to 90.96%–95.25%) and cold compressive strength (from 7.34–118.66 MPa to 303.39–546.65 MPa) with the increase in sintering temperature from 1300 to 1600 °C. In addition, it was found that Si promoted synthesis process of Mg₂SiO₄ phase through transient liquid phase sintering and Fe₂O₃ accelerated sintering process through activation sintering. Consequently, the presence of Mg₂SiO₄ phase effectively improved the density and strength of MgO–Mg₂SiO₄ composite ceramic, while reducing its thermal conductivity. This work provides a potential reutilization strategy for magnesite tailings, and as-prepared products are expected to be applied in fields of construction, metallurgy, and chemical industry.     

Ratiometric Detection of Glutathione Based on Disulfide Linkage Rupture between a FRET Coumarin Donor and a Rhodamine Acceptor

Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor. Under the excitation of the coumarin donor at 405 nm, the probe shows weak visible fluorescence of the coumarin donor at 470 nm and strong near-infrared fluorescence of the rhodamine acceptor at 652 nm due to efficient Forster resonance energy transfer (FRET) from the donor to the acceptor. Glutathione breaks the disulfide bond through reduction, which results in a dramatic increase in coumarin fluorescence and a corresponding decrease in rhodamine fluorescence. The probe possesses excellent cell permeability, biocompatibility, and good ratiometric fluorescence responses to glutathione and cysteine with a self-calibration capability. The probe was utilized to ratiometrically visualize glutathione concentration alterations in HeLa cells and Drosophila melanogaster larvae.     

5G-oriented Virtual Augmented Reality Scene Construction and Business Information Flow Demonstration

Mobile Networks and Applications - Aiming at the problems of large data volume, long calculation time, and information feedback speed in traditional virtual augmented reality-based scenes, this...     

Strong tribocatalytic dye degradation by tungsten bronze Ba4Nd2Fe2Nb8O30

The triboelectric effect has recently demonstrated its great potential in environmental remediation and even new energy applications for triggering a number of catalytic reactions by utilizing trivial mechanical energy. In this study, Ba₄Nd₂Fe₂Nb₈O₃₀ (BNFN) submicron powders were used to degrade organic dyes via the tribocatalytic effect. Under the frictional excitation of three PTFE stirring rods in a 5 mg/L RhB dye solution, BNFN demonstrates a high tribocatalytic degradation efficiency of 97% in 2 h. Hydroxyl radicals (?OH) and superoxide radicals (?O₂－) were also detected during the catalysis process, which proves that triboelectric energy stimulates BNFN to generate electron-hole pairs. The tribocatalysis of tungsten bronze BNFN submicron powders provides a novel and efficient method for the degradation of wastewater dye by utilizing trivial mechanical energy.