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The monitoring of acetone in exhaled breath is expected to provide a noninvasive and painless method for dynamic monitoring of summarized physiological metabolic status during obesity treatment. Although the commonly used Mass Spectrometry (MS) technology has high accuracy, the long detection time and large equipment size limit the application of daily bedside detection. As for the real-time and accurate detection of acetone, the gas sensor has become the best choice of gas detection technology, but it is easy to be disturbed by water vapor in breath gas. An integrated breath gas detection system based on cavity ring-down spectroscopy (CRDS) is reported in this paper, which is a laser absorption spectroscopy technique with high-sensitivity detection and absolute quantitative analysis. The system uses a 266 nm single-wavelength ultraviolet laser combined with a breath gas pretreatment unit to effectively remove the influence of water vapor. The ring-down time of this system was 1.068 μs, the detection sensitivity was 1 ppb, and the stability of the system was 0.13%. The detection principle of the integrated breath gas detection system follows Lambert–Beer’s law, which is an absolute measurement with very high detection accuracy, and was further validated by Gas Chromatography–Mass Spectrometer (GC-MS) testing. Significant differences in the response of the integrated breath gas detection system to simulated gases containing different concentrations of acetone indicate the potential of the system for the detection of trace amounts of acetone. Meanwhile, the monitoring of acetone during obesity treatment also signifies the feasibility of this system in the dynamic monitoring of physiological indicators, which is not only important for the optimization of the obesity treatment process but also promises to shed further light on the interaction between obesity treatment and physiological metabolism in medicine.

All-inorganic perovskites are rapidly emerging as novel optoelectronic functional materials owing to their fluorescence properties. However, the stability of these materials has always been the biggest challenge for their applications in photoelectric devices. Therefore, this study focuses on developing phosphor-aluminosilicate-based CsPbX3 (X = Cl, Br, and I) glass with a low reaction temperature by adding CsCO3, PbX2, and NaX to the raw materials in order to improve the stabilities. The glass network intermediates of SiO2 and Al2O3 doping in the raw material enhanced the stability of the pure phosphate glass network structure and devitrification while decreasing the melting temperature. Full chromatographic CsPbX3 quantum dots (QDs) encapsulated in phosphate-based glass were found to increase the fluorescence properties and quantum efficiency (>59%). Notably, the high water stability of CsPbX3 QDs glasses, with the maintenance of 90% luminous intensity, emerged when soaked in water. In addition, the excellent thermal stability and anti-ion exchange properties of the CsPbX3 QDs glasses were revealed. Benefiting from the above, multicolor light-emitting diode (LED) devices were assembled with a mixture of phosphors of CsPbX3 QDs glasses and commercial red-emission K2SiF6:Mn4+ phosphor spread on an InGaN chip, demonstrating bright light with superior luminous properties. Phosphor-aluminosilicate-based CsPbX3 QDs glass with high stability and low formation temperature would provide new methods for applications in lighting and displays.

Incorporating graphene as ceramic additives can significantly enhance both the toughness and self-lubricating characteristics of ceramic matrices. However, due to the difficult dispersion and easy agglomeration of graphene, the preparation process of composite ceramics still faces many problems. In this study, a laminated laser-induced reduced graphene oxide/hexagonal boron nitride (L-rGO/h-BN) was introduced as an additive into a silicon nitride matrix, then a silicon nitride/reduced graphene oxide/hexagonal boron nitride (Si3N4/L-rGO/h-BN) ceramic composite was successfully synthesized using Spark Plasma Sintering technology. This approach led to enhancements in both the mechanical and self-lubricating properties of silicon nitride ceramics. This is due to the good monodispersity of the incorporating graphene in the silicon nitride matrix. The flexural strength and fracture toughness of the ceramic composite experienced notable increases of 30.4% and 34.4%, respectively. Tribological experiments demonstrate a significant enhancement in the self-lubricating performance of ceramic composites upon the incorporation of L-rGO/h-BN. The coefficient of friction and wear spot diameter experienced reductions of 26.6% and 21%, respectively. These improvements extend the potential industrial applications of Si3N4/L-rGO/h-BN ceramic composites. Throughout the friction process, the evenly exposed rGO and h-BN demonstrate an effective self-lubricating effect on the wear surface. This research paves the way for a novel approach to fabricating high-performance self-lubricating structural ceramics.

The key challenges in aqueous zinc-manganese dioxide batteries (MnO2//Zn) are their poor electrochemical kinetics and stability, which are mainly due to low conductivity and the inevitable dissolution of MnO2. A synergistic combination of a Co-doped σ-MnO2 electrode (Co-MnO2) and a Co(CH3COO)2•4H2O (CoAc) electrolyte additive is here developed to design a high-performance aqueous MnO2//Zn battery (denoted as a Co-MnO2//Zn battery with CoAc). The introduction of Co ions (Co3+/Co2+) into the σ-MnO2 electrode is achieved via a facile one-step electrodeposition method. Benefitting from the synergistic coupling effect of the Co-MnO2 electrode and the CoAc electrolyte additive, the fabricated Co-MnO2//Zn battery with CoAc shows a commendable discharge capacity of 313.8 mAh g−1 at 0.5 A g−1, excellent rate performance, excellent durability over 1000 cycles (∼ 92% capacity retention at 1.0 A g−1) and admirable energy density (439.3 Wh kg−1), which is a significant improvement compared with an un-doped σ-MnO2//Zn battery.

Hexagonal boron nitride, as a layered material with a graphite-like structure, exhibits good mechanical, lubricating and oxidation resistance properties, and is thus expected to become one of the top choices for green lubricating oil additives. However, its poor dispersibility in oil and difficulties in preparing spherical particles when constructing hexagonal boron nitride limit its application. In this paper, spherical hexagonal boron nitride nanoparticles are constructed via a simple laser irradiation method. Under laser irradiation, raw irregular hexagonal boron nitride particles were reshaped into nanospheres via a laser-induced photothermal process and rapid cooling in a liquid-phase environment. Under the optimal concentration, the coefficient of friction and wear spot diameter decreased by 26.1% and 23.2%, and the surface roughness and wear volume decreased by 29.2% and 23.8%, respectively. The enhanced tribological performance is mainly due to the ball bearing, depositional absorption and repair effect of the spherical particles. This simple laser irradiation method provides a new method by which to prepare spherical hexagonal boron nitride lubricating oil additives.

To regulate the optical and electrical properties of the crystals and films of the intrinsic methylammonium lead iodide (CH3NH3PbI3), we dope them with sodium (Na) by selecting sodium iodide (NaI) as a dopant source. The highly conductive p-type sodium-doped CH3NH3PbI3 (MAPbI3: Na) perovskite single crystals and thin films are successfully grown using the inverse temperature crystallization (ITC) method and antisolvent spin-coating (ASC) method, respectively. With the increase of Na+ doping concentration, the grain size of the film increases, the surface becomes smoother, and the crystallinity improves. Hall effect results demonstrate that both the MAPbI3: Na thin films and single crystals change their quasi-insulating intrinsic conductivity to a highly conductive p-type conductivity. The room-temperature photoluminescence (PL) peaks of doped MAPbI3 films slightly blue shift, while the photocarriers' lifetime becomes longer. The optical fingerprints of the doped levels in MAPbI3: Na perovskites can be identified by temperature-dependent PL. Obvious fingerprints of Na-related acceptor (A0X) levels in the doped MAPbI3: Na were observed at 10 K. These results suggest that sodium doping is an effective way to grow highly conductive p-type MAPbI3 perovskites.

Supercapacitors (SCs) have attracted widespread attention due to their short charging/discharging time, long cycle life, and good temperature characteristics. Electrolytes have been considered as a key factor affecting the performance of SCs. They largely determine the energy density based on their decomposition voltage and the power density from their ionic conductivity. In recent years, redox electrolytes obtained a growing interest due to an additional redox activity from electrolytes, which offers an increased charge storage capacity in SCs. This article summarizes the latest progress in the research of redox electrolytes, and focuses on their properties, mechanisms, and applications based on different solvent types available. It also proposes potential solutions for how to effectively increase the energy density of the SCs while maintaining their high power and long life.