Analysis of research trends on hydrogen explosion by bibliometric approach.

As a carbon-free clean energy source and energy carrier, the risk of hydrogen explosion is one of the major problems in industrial production processes and has attracted a lot of attention from research scholars. According to the records in the Web of Science Core Collection database, a total of 1043 articles or reviews related to hydrogen explosion were published from 2001 to 2021. In this study, the collected literature information was visually analyzed using VOSviewer and CiteSpace. The results show that China, USA, Germany, and Japan are major contributors to hydrogen explosion research; the International Journal of Hydrogen Energy has the highest publications among all source journals. The research theme of hydrogen explosion has developed into two main directions: hydrogen mixture explosion characteristics and suppression methods, hydrogen explosion characteristics and suppression methods. Compared to traditional suppression methods, fine water mist is more efficient and environmentally friendly for the explosion of hydrogen and its mixtures. New research hotspots have appeared related to hydrogen fuel cells, the mechanism and prediction method of hydrogen VCE and DDT, explosive suppressants with engineering practicality and economy, and numerical methods that can accurately simulate the turbulence of hydrogen combustion. The results of the study can be used to help researchers quickly understand the current status and research frontiers of hydrogen explosion research and contribute to further research in the field.

HS-SPME/GC×GC-TOFMS-Based Flavoromics and Antimicrobial Properties of the Aroma Components of Zanthoxylum motuoense.

Zanthoxylum motuoense Huang, native to Tibet, China, is a newly discovered Chinese prickly ash, which, recently, has increasingly attracted the attention of researchers. In order to understand its volatile oil compositions and flavor characteristics, and to explore the flavor difference between Z. motuoense and the common Chinese prickly ash sold in the market, we analyzed the essential oils of Z. motuoense pericarp (MEO) using HS-SPME/GC×GC-TOFMS coupled with multivariate data and flavoromics analyses. The common commercial Chinese prickly ash in Asia, Zanthoxylum bungeanum (BEO), was used as a reference. A total of 212 aroma compounds from the 2 species were identified, among which alcohols, terpenoids, esters, aldehydes, and ketones were the major compounds. The predominant components detected from MEO were citronellal, (+)-citronellal, and ß-phellandrene. Six components-citronellal, (E,Z)-3,6-nonadien-1-ol, allyl methallyl ether, isopulegol, 3,7-dimethyl-6-octen-1-ol acetate, and 3,7-dimethyl-(R)-6-octen-1-ol-could be used as the potential biomarkers of MEO. The flavoromics analysis showed that MEO and BEO were significantly different in aroma note types. Furthermore, the content differences of several numb taste components in two kinds of prickly ash were quantitatively analyzed using RP-HPLC. The antimicrobial activities of MEO and BEO against four bacterial strains and nine plant pathogenic fungi were determined in vitro. The results indicated that MEO had significantly higher inhibitory activities against most microbial strains than BEO. This study has revealed the fundamental data in respect of the volatile compound properties and antimicrobial activity of Z. motuoense, offering basic information on valuable natural sources that can be utilized in the condiment, perfume, and antimicrobial sectors.

The role of atmospheric conditions in the nonradiative recombination in individual CH3NH3PbI3 perovskite crystals.

Organic-inorganic metal halide perovskites have been emerging as potential candidates for lightweight photovoltaic applications in space. However, fundamental physics concerning the effect of atmosphere on the radiative and nonradiative recombination in perovskites remains far from well understood. Here, we investigate the creation and annihilation of nonradiative recombination centers in individual CH3NH3PbI3 perovskite crystals by controlling the atmospheric conditions. We find that the photoluminescence (PL) of individual perovskite crystals can be quenched upon exposure from air to vacuum, while the subsequent PL enhancement in air shows a pressure dependence. Further analysis attributes the PL decline in vacuum to the activation of nonradiative trap sites, which is likely due to the lattice distortion caused by the variation of local strain on perovskites. With a gradual increase of the air pressure, the light-assisted chemisorption of oxygen on perovskite will passivate these nonradiative trap sites while simultaneously restoring the lattice imperfection, leading to PL enhancement. The present findings suggest that placing the perovskite in an environment with moderate oxygen content can protect the material from photophysical losses that can be pronounced under inert conditions.

Underestimated effect of the polymer encapsulation process on the photoluminescence of perovskite revealed by in situ single-particle detection.

Photostability has always been an important issue that limits the performance of organo-metal halide perovskites in optoelectronic devices. Although the photostability can be partially improved by polymer coating/encapsulation, one rising question that needs to be considered is whether the improvement of photostability is accessed at the expense of intangible loss in photoluminescence (PL) properties. By in situ analyzing the evolution of PL properties of individual perovskite crystals during the polymer encapsulation procedure, we demonstrate here that poly(methyl methacrylate), a common polymeric encapsulant, would passivate the surface defects of perovskite crystals, leading to the suppress of PL blinking. However, somewhat counterintuitive, the toluene solvent will induce the PL decline of individual perovskite crystals via accumulation of the number of quenchers that, most probably, are related to the ion migration in perovskite. The findings at the single-particle level emphasize the often-neglected role of the polymer matrix and the solvent in the optical properties of perovskite material during the polymer encapsulation process, and will guide the further design of more stable and high-performance devices based on perovskite.

Extraction optimization of Bruguiera gymnorrhiza polysaccharides with radical scavenging activities.

Box-Behnken design including independent variables such as extraction temperature (60-80°C), extraction time (20-40 min) and ratio of water to raw material (30-50 mL/g) was used to optimize the extraction process of Bruguiera gymnorrhiza polysaccharides (BGPs). The experimental data were fitted to a second-order polynomial equation using multiple regression analysis. The optimum conditions were predicted as follows: extraction temperature 71°C, extracting time 31.4 min, and ratio of water to raw material 42. Under these conditions, the yield of BGPs obtained was (16.43 ± 0.08)%, which was in good agreement with the predicted value 16.47%. Additionally, characterization of BGPs was obtained by FT-IR analysis. The antioxidant activities of BGPs were evaluated in vitro. BGPs demonstrated appreciable antioxidant potential on superoxide anion radical, ABTS radical, and hydroxyl radical scavenging. These may provide theoretical basis for further system research and rational development and utilization of mangrove resources.