Search

In the field of electric aircraft, the axial force of the conical motor is used to offset propeller thrust and reduce bearing wear. For the problem of accurate calculation of the no‐load axial force of the conical motor, combined with the characteristics that the rotor magnetic bridge of the hybrid conical inner‐mounted permanent magnet synchronous motor (HC‐IPMSM) is easy to be saturated and difficult to be calculated analytically, an equivalent analytical calculation method is proposed. According to the principle of constant air‐gap magnetic flux, the HC‐IPMSM is equivalent to many cylindrical surface‐mounted permanent magnet synchronous motors (CY‐SPMSM), and an analytical model is gained. Combining with the scalar magnetic potential Laplace equation and Poisson equation, the air‐gap flux density distribution on the rotor surface is calculated. And finally, the no‐load axial force of the motor is obtained by using the cone angle and the Maxwell stress method. Simulation and experiments verify the correctness and validity of the analytical model. [ABSTRACT FROM AUTHOR]

The in-depth understanding of the functions and interactions of multiple transition metal-based species in non-noble metal electrocatalysts is still obscure and challenges the oxygen reduction reaction (ORR). Herein, we rationally developed a Hm/Cy@C-900 electrocatalyst comprising multiple iron active sites of FeSx and Fe3C clusters and FeNx sites, which was characterized using XRD, S/TEM, and Mössbauer analyses. Hm/Cy@C-900 exhibited a high ORR performance (E1/2 0.845 V vs. RHE) in an O2-saturated KOH electrolyte, which outperformed the Hm/TCA@C-900 counterpart and commercial Pt–C electrocatalysts. Furthermore, the equipped zinc–air battery (ZAB) of Hm/Cy@C-900 could reach a power density of 192 mW cm−2@260.7 mA cm−2, which is much more efficient than that of Hm/TCA@C-900 (131 mW cm−2@201.2 mA cm−2) and a 20 wt% Pt–C catalyst (109 mW cm−2@221.3 mA cm−2). The superior ORR performance of Hm/Cy@C-900 was attributed to the promotional effect of FeSx and Fe3C clusters with FeNx active sites. Our work provides a rational design for and in-depth synthesis of FeNSC electrocatalysts for promoting the ZAB activity. [ABSTRACT FROM AUTHOR]

Doping of β-Ga2O3 with Al atoms provides an effective approach for further enlargement of the energy bandgap, and enhanced detection in the deep ultraviolet region. Although Al-doped β-Ga2O3 films have been prepared with various methods, challenges remain in the adjustment of crystal quality to obtain superior properties. In this paper, (AlxGa1–x)2O3 (denoted as AGO) films were deposited by magnetron co-sputtering at different bias voltages and annealed at 900°C in air. The dependence of the crystal structure, morphology, and optical properties of the films on bias voltage was investigated. The AGO films exhibit a preferred orientation in the ( 2 ¯ 01) plane at various biases, as evidenced by the x-ray diffraction measurements. The films with various bias voltages yield higher crystal quality with optical bandgap of about 5.0 eV. In addition, the AGO films demonstrate 95% absolute average transmittance in the UV-Vis wavelength range. This method thus opens a new way for controlling the quality and properties of AGO films with bias. [ABSTRACT FROM AUTHOR]

Stable isotope technique is important for understanding the structure and function of soil food web, which is considered as a belowground black box. We reviewed typical application cases of stable isotope techniques in the research of soil food webs, including to determine food sources and feeding preferences of soil fauna by using isotopes, and to analyze the trophic structure of soil food webs through isotope fractionation effects during the process of feeding and nutrient sequestration by soil fauna. Additionally, stable isotope techniques could reveal the role of soil biota at different trophic levels within soil food web in ecosystem matter and energy flow, which favored to carry out accurate and efficient research on the contribution of soil food webs to soil carbon and nitrogen cycling process and the corresponding influence mechanism. We further put forward the limitations of current stable isotope techniques and the future development directions. [ABSTRACT FROM AUTHOR]

To understand the health status of aquatic ecosystem in Lake Erhai, the community structure of benthic animals was investigated based on 27 samples from 11 typical monitoring sections in March, June, September and December 2021, and the benthic index of biotic integrity (B-IBI) assessment system was also established. The results showed that Lake Erhai contains 56 genera and species of benthic animals, which refers to 4 phyla, 6 classes, 28 families and 54 genera. The assessment system of B-IBI for Lake Erhai consists mainly of the total number of classification units, proportion of chironomid individuals, and BMWP index, which obtained by range test, discriminatory power and Pearson correlation screen. The health status of aquatic ecosystem in Lake Erhai can divide into five grades according to ratio scoring method, i.e., >2.61, 2.10~2.61, 1.82~2.10, 1.42~1.82 and <1.42, representing health, sub-health, fair, poor and very poor health status, respectively. Based on above method and standard, the health of aquatic ecosystem for Lake Erhai in 2021 is fair status. Specifically, five, six, five, nine and two sampling sites were in health, sub-health, fair, poor and very poor health status, accounting for 18.5%, 22.2%, 18.5%, 33.3% and 7.4% of the total sites, respectively. [ABSTRACT FROM AUTHOR]