Fabrication of high-efficiency Yb:Y2O3 laser ceramics without photodarkening

High-efficiency Yb:Y₂O₃ laser ceramics were fabricated using the vacuum-sintering plus hot isostatic pressing (HIP) without sintering additives. High-purity well-dispersed nanocrystalline Yb:Y₂O₃ powder was synthesized using a modified co-precipitation method in-house. The green bodies were first vacuum sintered at a temperature as low as 1430°C and then HIPed at 1450°C. Finally, the samples were air annealed at 800°C for 10 h. Although no sintering aids were used, full density of the samples with excellent optical homogeneity and an inline transmission of 80% at 400 nm could be obtained. Moreover, photodarkening phenomenon was not detected in the ceramics. Preliminary laser experiment with the fabricated ceramics in a two-mirror cavity has demonstrated 32 W continuous-wave (CW) output at ∼1077 nm with an optical-to-optical conversion efficiency of 58.2%. To the best of our knowledge, this is so far the highest CW output power and optical-to-optical conversion efficiency achieved with the Yb³⁺-doped sesquioxide ceramics in a simple two-mirror cavity.     

Acid–base transport model depicting the dynamic pH response of interfacial reactions

Acid–base transport is integral to many important interfacial reactions in various fields of chemistry, but its theoretical foundation is lacked. Herein, a common acid–base transport model is established owing to the success in deriving buffer transport equations. This model is applicable to most buffer systems by flexibly integrating the transport equations in terms of buffer components, and is verified through the model relationships of buffer transport limiting current by using hydrogen evolution reaction experiments. Based on model calculations, two diagram approaches are proposed to depict the dynamic pH response and aid buffer operation optimizations. The model and methods allow us to quantify the rate-limiting effect of acid–base transport on interfacial reactions and to precisely control the effect through medium regulations. Furthermore, the model has laid the foundation of dynamic pH effect on species transformation and process mechanism, which can be of wide interest in the chemistry encompassing interfacial reactions.     

Metal modified (Ni,Ce, Ta) Ti/SnO2–Sb2O5–RuO2 electrodes for enhanced electrochemical degradation of Orange G

Journal of Applied Electrochemistry - Ni, Ce, and Ta modified Ti/SnO2–Sb2O5–RuO2 anodes were first prepared by thermal decomposition strategy and applied for Orange G degradation to...     

磁齿轮复合永磁电机拓扑及应用综述

磁齿轮复合电机（MGM）是一种自带减速效应的新型多气隙磁场调制型永磁电机，因其转矩密度大、功率因数高，近年来在混动/电动汽车、低速大转矩直驱、航空航天等领域的应用前景获得了业界的广泛关注；MGM非接触传动的特点使其在医药食品、新能源发电、石油化工等方面具有发展潜力。该文首先介绍磁力齿轮及多种磁齿轮复合电机的工作原理，介绍和比较磁齿轮与电机常见的复合方式及其特点；按照单元排布方式、调制结构、电机及磁齿轮类型等分类梳理近年来MGM在拓扑结构上的研究和创新，介绍各类磁通方向及运行方式MGM的研究。然后介绍MGM近年来在高减速比、低成本、无级变速等一些关键问题上的进展。最后总结磁齿轮复合电机的业界应用现状，并对其应用前景进行展望。