Sr 99% RE 1% TiO 3 crystals were prepared by Verneuil method and their dielectric properties were studied. The simultaneous substitution of Sr 2+ and Ti 4+ may be able to obtain superior dielectric properties compared to the substitution of Sr 2+ only.
Patchy vegetation is a very common phenomenon due to long-term overgrazing in degraded steppe grasslands, which results in substantial uncertainty associated with soil carbon (C) and nitrogen (N) dynamics because of changes in the amount of litter accumulation and nutrition input into soil.We investigated soil C and N stocks beneath three types of monodominant species patches according to community dominance. Stipa krylovii patches, Artemisia frigida patches, and Potentilla acaulis patches represent better to worse vegetation conditions in a grassland in northern China.The results revealed that the soil C stock (0-40 cm) changed significantly, from 84.7 to 95.7 Mg ha-1, and that the soil organic carbon content (0-10 cm) and microbial biomass carbon (0-10 and 10-20 cm) varied remarkably among the different monodominant species communities (P < 0.05). However, soil total nitrogen and microbial biomass nitrogen showed no significant differences among different plant patches in the top 0-20 cm of topsoil. The soil C stocks under the P. acaulis and S. krylovii patches were greater than that under the A. frigida patch. Our study implies that accurate estimates of soil C and N storage in degenerated grassland require integrated analyses of the concurrent effects of differences in plant community composition.
In response to the practical demands for data sharing and exchange in the field of rack railway systems engineering, as well as to address the gaps in the rack railway domain within the framework of the IFC4 standard, we extend and define the rack railway domain through entity extension and custom attribute sets. By utilizing the ongoing construction of the Dujiangyan to Mount Siguniang Railway as a case study, we validate the utility of this IFC extension and modeling approach. Leveraging IfcOpenShell, we incorporate the extended data content into the generated IFC file. We present a process for extension tailored to the characteristics of rack railway engineering. This study aims to provide broader information support for the digital construction of track structures in the design phase of rack railway engineering and to facilitate more efficient data exchange and sharing.
Particulate matter (PM) emitted from livestock and poultry production contributes to atmospheric aerosol loading, affecting animal health and the surrounding atmospheric environment. However, developing and optimizing remediation technologies require a better understanding of air pollutant concentrations, the emission plumes, and the mechanism of emission. Previous studies have primarily focused on indoor air pollution research, while outdoor research is relatively rare. Field test research is not only costly but also consumes extensive amounts of time. The application of computational fluid dynamics (CFD) technology can save a lot of measurement time and repetitive labor, in order to better understand the diffusion fundamentals and spatial and temporal distribution differences of PM. This study monitored the PM concentrations of different particle sizes inside and outside a layer house with negative pressure ventilation in Northeast China during the summer of 2021. These data were also used to validate the three-dimensional simulation of the PM concentrations inside and outside of the layer house in various scenarios of wind directions at different times by CFD technology. Through correlation analysis, it is found that temperature was positively correlated with PM1 and PM2.5, and relative humidity and wind speed were negatively correlated with PM, which has a greater impact on PM10 and total suspended particulate (TSP). The particle size was proportional to the diffusion distance and diffusion height, time, and wind direction both have an impact on the spread of PM. Considering the environmental conditions in Northeast China, increasing the height of the fan by 1 m was suggested to reduce the diffusion of PM concentration. In addition, the diffusion patterns and transport paths in this study provide valuable information for improving control measures to minimize the influence of PM on both animal health and air quality.
A high-performance solid-state electrolyte was obtained based on hydroxypolybenzimidazole grafting with the anion exchange silica precursor (AESP). The introduction of rigid polymer chains and quaternary ammonium groups not only increases mechanical strength but also greatly improves electrical conductivity. The obtained membranes maintain excellent mechanical properties about 23.1 MPa even after doping with 3.5 M KOH for 72 h and high hydroxide conductivity of about 0.077 S/cm (remaining above 0.043 S/cm after 216 h). There are few studies on the application of AEMs as electrolytes for all-solid-state supercapacitors (ASCs) currently. Therefore, the attempt was made to assemble the ASCs by using the PBIOH-AESP X membranes and activated carbon (AC) electrodes. The supercapacitor exhibits remarkable cycle stability (the capacitance retention rate is 87% and the Coulomb efficiency is 94.2% after 6000 GCD cycles) and a very high power density (82.32 kW/kg). In addition, three series connected supercapacitors illuminated a 3 V LED for more than 20 s. These results indicate that the polymer membranes are promising electrolytes for supercapacitors.
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