RESUMO
The McMurry coupling is a facile, gentle and low-cost chemical reaction for synthesizing. Here, for the first time, we employed the McMurry coupling reaction to prepare π-conjugated anion exchange membranes (AEMs). The inter-chain π-π stacking between adjacent benzene rings induces directional self-assembly aggregation and enables highly ordered ion-conductive channels. The resulting structure was characterized through UV/VIS spectrum, X-ray diffraction (XRD) pattern, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and density functional theory (DFT) calculations, leading to high OH- conductivity of 135.5â mS cm-1 at 80 °C. Furthermore, the double bonds in the π-conjugated system also trigger in situ self-crosslinking of the AEMs to enhance dimensional and alkaline stability. Benefiting from this advantage, the as-obtained Cr-QPPV-2.51 AEM exhibits superior alkaline stability (95 % conductivity retention after 3000â hrs in 1â M KOH at 80 °C) and high mechanical strength of 34.8â MPa. Moreover, the fuel cell using Cr-QPPV-2.51 shows a maximum peak power density of 1.27â W cm-2 at 80 °C.
RESUMO
This paper thoroughly examines the time distribution, author collaboration, research institutions, research hotspots, theme clustering, and research changes and trends based on 345 CNKI literatures in the field of blended learning for Business English majors in China from 2012 to 2022. It reveals that: Research on blended learning for Business English majors in China from 2012 to 2022 can be divided into Steady Start Stage (2012-2017), Rapid Growth Stage (2018-2020) and Stable Development Stage (2021-2022). High-frequency keywords such as blended teaching mode, MOOC, flipped classroom, SPOC, etc. are hotspots of current scholars' attention. The themes of research on blended learning of business English majors in China mainly include Teaching Reform of Business English Majors, Exploration of Blended Teaching Mode and Design, and Application of Internet Teaching Platform. "Teaching Reform", "Online and Offline", "Application of Smart Platform" are the current research frontier issues in the development of blended learning for Business English majors in China. In general, China's research on blended learning for business English majors has achieved fruitful results under China's policies. Future research should concentrate on the construction of a technology environment for blended learning between learners, a variety of intelligent learning tools and mobile devices, and should be steadily bolstered in the field of blended learning for business English majors, particularly in practical application, effectiveness analysis, distance education, training and continuing education, innovation education, etc.
RESUMO
As a central component for anion exchange membrane fuel cells (AEMFCs), the anion exchange membrane is now facing the challenge of further improving its conductivity and alkali stability. Herein, a twisted all-carbon backbone is designed by introducing stereo-contorted units with piperidinium groups dangled at the twisted sites. The rigid and twisted backbone improves the conduction of hydroxide and brings down the squeezing effect of the backbone on piperidine rings. Accordingly, an anion exchange membrane prepared through this method exhibits adapted OH- conductivity, low swelling ratio and excellent alkali stability, even in high alkali concentrations. Further, a fuel cell assembled with a such-prepared membrane can reach a power density of 904.2 mW/cm2 and be capable of continuous operation for over 50 h. These results demonstrate that the designed membrane has good potential for applications in AEMFCs.
RESUMO
Amidst the COVID-19, which has necessitated the widespread use of distant learning, there has been a notable increase in the recognition and utilization of inventive pedagogical methods and technological tools in the field of language teaching. The primary objective of this research is to assess the effects of DingTalk-based PBL on the business vocabulary growth of Chinese undergraduates during the pandemic, with a particular focus on remote learning environments. This mixed-methods research employed a sample of 58 participants. The study involved both quantitative vocabulary assessments and qualitative interviews. The quantitative assessments aimed to measure the impact on vocabulary scores, while qualitative interviews were conducted to gather insights into participants' experiences and perceptions regarding DingTalk-based PBL. The quantitative assessment revealed a significant improvement in business vocabulary scores among the participants who underwent DingTalk-based PBL. This result indicates the platform's potential to enhance language acquisition. The qualitative interviews provided further insights, with participants expressing positive attitudes toward DingTalk-based PBL. They emphasized its capacity to sustain engagement, foster collaboration, and bridge the gap between remote learning and effective language acquisition. These findings underscore the transformative potential of DingTalk-based PBL in language education, especially in the context of challenges posed by the pandemic. While recognizing the constraints of this study, such as its limited duration and restricted contextual applicability, the research encourages further investigation into sustainable vocabulary expansion, the development of multifaceted language abilities, and the integration of these platforms into emerging hybrid educational frameworks. This study makes a valuable contribution to the ongoing discourse regarding novel technology-based methods in language instruction, providing relevant insights applicable to both present and future educational contexts.